OneCAD-Draft/src/app/command_driver.rs

use super::{Message, OpenCADStudio};
use crate::command::{CmdResult, SelectionEntity, StepInput};
use acadrust::Handle;
use iced::Task;

impl OpenCADStudio {
    pub(super) fn reject_locked_edit(&mut self, i: usize, handle: Handle) -> bool {
        let Some(layer) = self.tabs[i].scene.locked_layer_name(handle) else {
            return false;
        };
        self.command_line.push_info(crate::tf!(
            "Object is on locked layer \"{layer}\" — unlock the layer to edit it."
        ).as_ref());
        true
    }

    pub(super) fn refresh_area_preview(&mut self, i: usize) {
        let hatches = self.tabs[i]
            .active_cmd
            .as_ref()
            .and_then(|command| command.hatch_preview_models());
        if let Some(hatches) = hatches {
            self.tabs[i].scene.set_command_preview_hatches(hatches);
            return;
        }
        let regions = self.tabs[i]
            .active_cmd
            .as_ref()
            .and_then(|command| command.area_preview_regions());
        if let Some(regions) = regions {
            self.tabs[i].scene.set_area_preview_regions(&regions);
        }
    }

    /// Point supplied by a bare Enter before LINE/PLINE's first click. Prefer
    /// the current endpoint of the most recently created path drawable in the
    /// active space. A loaded drawing has no runtime anchor, so recover its
    /// newest line/arc/polyline endpoint. An empty space starts at the active
    /// UCS origin (0,0,0 in user coordinates).
    fn default_draw_start(&self, i: usize) -> glam::DVec3 {
        let tab = &self.tabs[i];
        let endpoint = |entity: &acadrust::EntityType| {
            let last_grip = match entity {
                acadrust::EntityType::Line(line) => {
                    return Some(glam::DVec3::new(
                        line.end.x,
                        line.end.y,
                        line.end.z,
                    ));
                }
                acadrust::EntityType::Arc(_) => Some(2),
                acadrust::EntityType::LwPolyline(polyline) => {
                    polyline.vertices.len().checked_sub(1)
                }
                acadrust::EntityType::Polyline(polyline) => {
                    polyline.vertices.len().checked_sub(1)
                }
                acadrust::EntityType::Polyline2D(polyline) => {
                    polyline.vertices.len().checked_sub(1)
                }
                acadrust::EntityType::Polyline3D(polyline) => {
                    polyline.vertices.len().checked_sub(1)
                }
                _ => None,
            }?;
            crate::scene::view::dispatch::grips(entity)
                .into_iter()
                .find(|grip| grip.id == last_grip)
                .map(|grip| grip.world)
        };

        if let Some(handle) = tab.last_draw_anchor {
            if tab.scene.entity_belongs_to_active_space(handle) {
                if let Some(point) = tab.scene.document.get_entity(handle).and_then(endpoint) {
                    return point;
                }
            }
        }

        let recovered = tab
            .scene
            .document
            .entities()
            .filter_map(|entity| {
                let handle = entity.common().handle;
                tab.scene
                    .entity_belongs_to_active_space(handle)
                    .then(|| endpoint(entity).map(|point| (handle, point)))
                    .flatten()
            })
            .max_by_key(|(handle, _)| handle.value())
            .map(|(_, point)| point);

        recovered.unwrap_or_else(|| tab.ucs_origin_world())
    }

    /// Drop cursor-relative state that was computed in the drawing space being
    /// left. This is also used by MVIEW, whose command object survives its
    /// intentional paper/model round-trip while its old-space overlays cannot.
    pub(super) fn reset_space_interaction_state(&mut self) {
        let i = self.active_tab;
        self.tabs[i].scene.clear_preview_wire();
        self.tabs[i].snap_result = None;
        self.last_point = None;
        // Points collected in the space being left are meaningless in the new
        // one (PR1).
        self.clear_accepted_snaps();
        self.pending_click_snap = None;
        self.snapper.from_point = None;
        self.snapper.clear_tracking();
        self.otrack_active = None;
        self.otrack_kind = None;
        self.axis_lock_dir = None;
        self.dyn_user_reshaped = false;
        self.dyn_coord_absolute = false;
        self.grip_hover = None;
        self.grip_popup = None;
        self.grip_pending = None;
        self.visibility_popup = None;
        self.hover_dwell = None;
        self.ucs_grip_drag = None;
        self.ucs_icon_selected = false;
        self.ucs_icon_hover = false;
        self.tabs[i].pan_mode = false;
        self.tabs[i].orbit_mode = false;
        self.tabs[i].zoom_dynamic_mode = false;
        let _ = self.on_viewport_exit();
    }

    /// Roll a hot grip back to its pre-drag image and remove every grip-owned
    /// overlay. Shared by Escape and drawing-space transitions.
    pub(super) fn capture_grip_history_originals(&mut self, i: usize, handles: &[Handle]) {
        if !self.grip_history_originals.is_empty() {
            return;
        }
        self.grip_history_originals = handles
            .iter()
            .filter_map(|&handle| {
                let objects = self.tabs[i].scene.solid_history_objects(handle);
                (!objects.is_empty()).then_some((handle, objects))
            })
            .collect();
    }

    pub(super) fn cancel_active_grip_edit(&mut self) -> bool {
        let i = self.active_tab;
        let had_grip = self.tabs[i].active_grip.take().is_some()
            || self.grip_add_provisional.is_some()
            || !self.grip_preview_handles.is_empty()
            || !self.grip_history_originals.is_empty();
        if !had_grip {
            return false;
        }

        // An Add-Leader arrow being placed is still provisional.
        if let Some((handle, grip_id)) = self.grip_add_provisional.take() {
            use crate::entities::traits::EntityTypeOps;
            if let Some(entity) = self.tabs[i].scene.document.get_entity_mut(handle) {
                entity.apply_grip_menu(
                    grip_id,
                    crate::scene::model::object::GripMenuAction::RemoveLeader,
                );
            }
            self.tabs[i]
                .scene
                .bump_entities(&[(handle, crate::scene::ChangeKind::Modified)]);
        }

        let handles = std::mem::take(&mut self.grip_preview_handles);
        let originals = std::mem::take(&mut self.grip_originals);
        let history_originals = std::mem::take(&mut self.grip_history_originals);
        let history_handles: rustc_hash::FxHashSet<_> = history_originals
            .iter()
            .map(|(handle, _)| *handle)
            .collect();
        for (_, objects) in history_originals {
            for (object_handle, object) in objects {
                self.tabs[i]
                    .scene
                    .document
                    .objects
                    .insert(object_handle, object);
            }
        }
        let mut changed_handles: rustc_hash::FxHashSet<_> = handles.iter().copied().collect();
        for (handle, original) in originals {
            changed_handles.insert(handle);
            if !history_handles.contains(&handle) {
                let current = self.tabs[i]
                    .scene
                    .document
                    .get_entity(handle)
                    .and_then(crate::entities::solid3d::point_of_reference)
                    .map(|point| [point.x, point.y, point.z]);
                let target = crate::entities::solid3d::point_of_reference(&original)
                    .map(|point| [point.x, point.y, point.z]);
                if let (Some(current), Some(target)) = (current, target) {
                    self.tabs[i].scene.translate_solid_geometry(
                        handle,
                        [
                            target[0] - current[0],
                            target[1] - current[1],
                            target[2] - current[2],
                        ],
                    );
                }
            }
            if let Some(entity) = self.tabs[i].scene.document.get_entity_mut(handle) {
                *entity = original;
            }
        }
        for handle in history_handles {
            let restored = self.tabs[i]
                .scene
                .document
                .solid_history_operation(handle)
                .cloned()
                .is_some_and(|operation| {
                    self.tabs[i]
                        .scene
                        .rebuild_solid_history(handle, operation)
                });
            if !restored {
                self.tabs[i].scene.reseed_derived_caches(handle);
            }
        }
        for &handle in &handles {
            self.tabs[i].scene.preview_hidden.remove(&handle);
        }
        let changes: Vec<_> = changed_handles
            .into_iter()
            .map(|handle| (handle, crate::scene::ChangeKind::Modified))
            .collect();
        self.tabs[i].scene.bump_entities(&changes);
        if let Some(dirty_before) = self.grip_dirty_before.take() {
            self.tabs[i].dirty = dirty_before;
        }

        self.grip_reference_wires.clear();
        self.grip_text_verts.clear();
        self.grip_text_slide = false;
        self.tabs[i].scene.clear_preview_wire();
        self.tabs[i].snap_result = None;
        self.refresh_selected_grips();
        self.refresh_properties();
        true
    }

    /// End an interactive command before its drawing coordinate context
    /// changes. This is a full interaction boundary, not only an `active_cmd`
    /// check: grip drags, suspended editor commands, snaps, tracking, dynamic
    /// input and pointer gestures all carry coordinates from the old space.
    pub(super) fn cancel_active_command_for_space_change(&mut self) -> Task<Message> {
        let i = self.active_tab;
        let mut tasks = Vec::new();
        let mut cancellation_reported = false;

        if let Some(result) = self.tabs[i]
            .active_cmd
            .as_mut()
            .map(|command| command.on_space_change())
        {
            let (result, message_pending) = match result {
                CmdResult::Cancel => (CmdResult::CancelForSpaceChange, false),
                other => (other, true),
            };
            tasks.push(self.apply_cmd_result(result));

            // `on_space_change` must be terminal. Force a plain cancellation
            // if an external/plugin command violates that contract.
            if self.tabs[i].active_cmd.is_some() {
                tasks.push(self.apply_cmd_result(CmdResult::CancelForSpaceChange));
            } else if message_pending {
                self.command_line
                    .push_info(crate::t!("Command cancelled because the active drawing space changed.").as_ref());
            }
            cancellation_reported = true;
        }

        let grip_cancelled = self.cancel_active_grip_edit();
        let suspended_cancelled = self.tabs[i].suspended_cmd.take().is_some();
        let editor_cancelled = self.text_inline.is_some() || self.mtext_editor.is_some();
        if editor_cancelled {
            self.text_inline_cancel();
            self.mtext_cancel();
        }
        if !cancellation_reported && (grip_cancelled || suspended_cancelled || editor_cancelled) {
            self.command_line
                .push_info(crate::t!("Command cancelled because the active drawing space changed.").as_ref());
        }

        self.command_line.input.clear();
        self.command_line.autocomplete_cursor = None;
        self.command_line.close_history();
        self.reset_space_interaction_state();
        if tasks.is_empty() {
            Task::none()
        } else {
            Task::batch(tasks)
        }
    }

    /// Apply LIMCHECK/PLIMCHECK to a point before an interactive command
    /// consumes it. LIMITS itself must be able to redefine a rectangle beyond
    /// the old boundary, so it is the sole bypass.
    pub(super) fn command_point_allowed(&mut self, i: usize, point: glam::DVec3) -> bool {
        let checks_limits = self.tabs[i]
            .active_cmd
            .as_ref()
            .is_some_and(|command| command.name() != "LIMITS")
            && self.tabs[i].scene.drawing_limit_check_enabled();
        if checks_limits && !self.tabs[i].scene.point_inside_drawing_limits(point) {
            self.command_line.push_error(crate::t!("Outside limits.").as_ref());
            return false;
        }
        true
    }

    /// Refresh screen-space feature picking immediately before point dispatch.
    pub(super) fn refresh_command_point_pick_context(&mut self, i: usize) {
        if self.tabs[i].active_cmd.as_ref()
            .is_some_and(|command| command.wants_point_pick_context())
        {
            let scene = &self.tabs[i].scene;
            let size = scene.selection.borrow().vp_size;
            let edit = scene.viewport_edit_frame(size);
            let tile = edit.as_ref().map(|(_, rect)| *rect)
                .unwrap_or_else(|| scene.active_model_tile_bounds(size.0, size.1));
            let bounds = iced::Rectangle { x: 0.0, y: 0.0, width: tile.width, height: tile.height };
            let context = if bounds.width > 0.0 && bounds.height > 0.0 {
                let (view, eye) = if let Some((camera, _)) = edit {
                    (camera.view_proj_rte(bounds), camera.eye())
                } else {
                    let camera = scene.camera.borrow();
                    (camera.view_proj_rte(bounds), camera.eye())
                };
                Some(crate::command::PointPickContext { view, eye, bounds,
                    aperture_px: crate::ui::overlay::pick_box_aperture_px(self.pick_box) })
            } else { None };
            if let Some(command) = self.tabs[i].active_cmd.as_mut() {
                command.set_point_pick_context(context);
            }
        }
    }

    /// Drive the active command's step machine with one [`StepInput`], then
    /// apply the result. This is the single entry point every input source
    /// (command line, headless, dynamic input, plugin API, viewport) funnels
    /// through, so the routing from input → `on_*` method → `apply_cmd_result`
    /// lives in exactly one place. No-op when no command is active.
    pub(super) fn feed_command(&mut self, input: StepInput) -> Task<Message> {
        // Selection keywords (P / PREVIOUS, L / LAST) consume the token
        // before it reaches the command (#426).
        if let StepInput::Text(s) = &input {
            let kw_input = s.clone();
            if let Some(task) = self.try_selection_keyword(&kw_input) {
                return task;
            }
        }
        let i = self.active_tab;
        let default_start = matches!(&input, StepInput::Enter)
            && self.tabs[i]
                .active_cmd
                .as_ref()
                .is_some_and(|command| command.enter_accepts_default_start());
        let input = if default_start {
            StepInput::Point(self.default_draw_start(i))
        } else {
            input
        };
        if let StepInput::Point(point) = &input {
            if !self.command_point_allowed(i, *point) {
                return Task::none();
            }
            // Typed / dynamic-input / headless points carry no snap, but the
            // accepted-snap list must stay index-parallel with the points the
            // command collects (PR1). Interactive picks record themselves in
            // the click handler and never reach here.
            self.record_accepted_snap(i, None, None, *point);
        }
        if default_start {
            let StepInput::Point(point) = &input else {
                unreachable!("default command start must be a point");
            };
            self.last_point = Some(*point);
            self.dyn_user_reshaped = false;
            self.dyn_coord_absolute = false;
            self.sync_dyn_fields();
            self.reset_tracking_after_point();
            self.push_ucs_to_cmd(i);
        }
        if let StepInput::EntityPick(handle, point) = &input {
            let solid_pick = matches!(
                self.tabs[i].scene.document.get_entity(*handle),
                Some(
                    acadrust::EntityType::Solid3D(_)
                        | acadrust::EntityType::Surface(_)
                        | acadrust::EntityType::Region(_)
                        | acadrust::EntityType::Body(_)
                )
            );
            let direction = if solid_pick {
                self.tabs[i]
                    .scene
                    .solid_planar_face_normal_at(*handle, *point)
            } else {
                self.tabs[i]
                    .scene
                    .document
                    .get_entity(*handle)
                    .and_then(crate::entities::curve::entity_curve)
                    .and_then(|curve| curve.plane.normal())
                    .map(glam::DVec3::from_array)
            };
            if let Some(command) = self.tabs[i].active_cmd.as_mut() {
                command.set_entity_pick_direction(direction);
            }
            if self.tabs[i].active_cmd.as_ref()
                .is_some_and(|command| command.inject_before_entity_pick())
            {
                if let Some(entity) = self.tabs[i].scene.document.get_entity(*handle).cloned() {
                    if let Some(command) = self.tabs[i].active_cmd.as_mut() {
                        command.inject_picked_entity(entity);
                    }
                }
            }
        }
        if let StepInput::SelectionComplete(handles) = &input {
            let exclude_locked = self.tabs[i].active_cmd.as_ref()
                .is_some_and(|command| command.selection_entities_exclude_locked());
            let entities = {
                let scene = &self.tabs[i].scene;
                handles
                    .iter()
                    .filter(|handle| !exclude_locked || !scene.is_layer_locked(**handle))
                    .filter_map(|handle| {
                        scene.document.get_entity(*handle).cloned().map(|entity| {
                            let surface_area = scene
                                .meshes
                                .get(handle)
                                .or_else(|| scene.block_meshes.get(handle))
                                .map(|mesh| mesh.metrics.surface_area);
                            SelectionEntity {
                                handle: *handle,
                                entity,
                                surface_area,
                            }
                        })
                    })
                    .collect()
            };
            if let Some(command) = self.tabs[i].active_cmd.as_mut() {
                command.inject_selection_entities(entities);
            }
        }
        if matches!(&input, StepInput::Point(_)) { self.refresh_command_point_pick_context(i); }
        let ctrl = self.ctrl_down;
        let shift = self.shift_down;
        let result: Option<CmdResult> = {
            let Some(cmd) = self.tabs[i].active_cmd.as_mut() else {
                return Task::none();
            };
            cmd.set_ctrl(ctrl);
            cmd.set_shift(shift);
            match input {
                StepInput::Point(p) => Some(cmd.on_point(p)),
                StepInput::Text(s) => cmd.on_text_input(&s),
                StepInput::EntityPick(h, p) => Some(cmd.on_entity_pick(h, p)),
                StepInput::StructurePick(h, p) => Some(cmd.on_structure_pick(h, p)),
                StepInput::SelectionComplete(hs) => Some(cmd.on_selection_complete(hs)),
                StepInput::Tangent(o, p) => Some(cmd.on_tangent_point(o, p)),
                StepInput::EditorClosed(c) => Some(cmd.on_editor_closed(c)),
                StepInput::Enter => Some(cmd.on_enter()),
                StepInput::Escape => Some(cmd.on_escape()),
            }
        };
        match result {
            Some(r) => self.apply_cmd_result(r),
            None => Task::none(),
        }
    }

    /// Run one whole command-line string. A single word or an inline-argument
    /// command (`PDMODE 3`, `LAYER Walls`, `UCS Z 90` pasted as one line)
    /// dispatches as-is; for a multi-token line whose first word starts an
    /// interactive tool (`LINE 0,0 10,10`) the first word starts the tool and the
    /// remaining tokens are fed as points / option keywords, then the command is
    /// terminated as if Enter were pressed. Shared by the GUI command line and
    /// the headless automation feeder so both behave identically.
    pub(super) fn run_command_line(&mut self, cmd: &str) -> Task<Message> {
        let i = self.active_tab;
        let tokens: Vec<&str> = cmd.split_whitespace().collect();
        if tokens.len() <= 1 {
            return self.dispatch_command(cmd);
        }
        // Plugin commands parse their own inline arguments from the whole line
        // (e.g. `HC_PIPE 2B 2C 1.25 0.013`), so offer the full command to plugin
        // dispatch first. A built-in interactive tool matches only its bare name
        // (`LINE`), so the full line is not a plugin command and falls through to
        // the first-word + fed-tokens path below. (#162)
        if crate::plugin::try_dispatch(self, i, cmd) {
            let toks: Vec<String> = tokens.iter().map(|s| s.to_string()).collect();
            return self.finish_active_command(&toks);
        }
        if tokens[0].eq_ignore_ascii_case("BACKGROUND")
            || tokens[0].eq_ignore_ascii_case("COLORSCHEME")
        {
            return self.dispatch_command(cmd);
        }
        let start_task = self.dispatch_command(tokens[0]);
        if self.tabs[i].active_cmd.is_none() {
            // Not an interactive tool — an inline-argument command (`PDMODE 3`).
            return self.dispatch_command(cmd);
        }
        let toks: Vec<String> = tokens.iter().map(|s| s.to_string()).collect();
        let finish_task = self.finish_active_command(&toks);
        Task::batch([start_task, finish_task])
    }

    /// Feed `tokens[1..]` to the active interactive command as points / option
    /// keywords, then terminate it as if Enter were pressed. No-op when no
    /// command is active.
    pub(super) fn finish_active_command(&mut self, tokens: &[String]) -> Task<Message> {
        let i = self.active_tab;
        if self.tabs[i].active_cmd.is_none() {
            return Task::none();
        }
        self.last_point = None;
        let mut tasks = Vec::new();
        for tok in &tokens[1..] {
            if self.tabs[i].active_cmd.is_none() {
                break;
            }
            tasks.push(self.feed_active_cmd(tok));
        }
        tasks.push(self.feed_command(StepInput::Enter));
        Task::batch(tasks)
    }

    /// Classify one typed token into a [`StepInput`] and route it through the
    /// shared [`Self::feed_command`]. An object-pick step takes a hex handle; a
    /// coordinate is parsed (and, like the GUI command line, interpreted in the
    /// active UCS); anything else is an option keyword / value. Used by both the
    /// GUI command line and headless automation.
    /// Standard selection keywords at a "Select objects:" prompt (#426):
    /// P / PREVIOUS re-selects the set the last command worked on, and
    /// L / LAST selects the most recently created object in the current
    /// space. Returns `Some` when the token was consumed as a keyword.
    /// Handled centrally so every gathering command gets them for free.
    pub(super) fn try_selection_keyword(&mut self, text: &str) -> Option<Task<Message>> {
        let i = self.active_tab;
        let gathering = self.tabs[i]
            .active_cmd
            .as_ref()
            .map_or(false, |c| c.is_selection_gathering());
        if !gathering {
            return None;
        }
        let kw = text.trim().to_ascii_uppercase();

        // Modes that arm the next gesture rather than selecting anything now.
        // Dragging normally decides window-vs-crossing from the direction the
        // corner travels; asking for one by name has to override that, and hold
        // the override until the box is finished. (#596)
        if let "W" | "WINDOW" | "C" | "CROSSING" = kw.as_str() {
            let crossing = matches!(kw.as_str(), "C" | "CROSSING");
            {
                let mut selection = self.tabs[i].scene.selection.borrow_mut();
                selection.box_crossing = crossing;
                selection.box_crossing_locked = true;
            }
            let hint = if crossing {
                crate::t!("Crossing: specify first corner.")
            } else {
                crate::t!("Window: specify first corner.")
            };
            self.command_line.push_info(hint.as_ref());
            return Some(Task::none());
        }

        // Whether a pick adds to the set or takes away from it, for the rest of
        // this selection. Mirrors PICKADD, which the pick paths already read.
        if let "R" | "REMOVE" | "A" | "ADD" = kw.as_str() {
            let adding = matches!(kw.as_str(), "A" | "ADD");
            self.select_remove_mode = !adding;
            let hint = if adding {
                crate::t!("Add mode: picks join the selection.")
            } else {
                crate::t!("Remove mode: picks leave the selection.")
            };
            self.command_line.push_info(hint.as_ref());
            return Some(Task::none());
        }

        let add: Vec<Handle> = match kw.as_str() {
            // Every selectable object of the current space.
            "ALL" => self.tabs[i]
                .scene
                .entity_wires()
                .iter()
                .filter_map(|w| crate::scene::Scene::handle_from_wire_name(&w.name))
                .collect(),
            "P" | "PREVIOUS" => self.tabs[i]
                .prev_selection
                .iter()
                .copied()
                .filter(|&h| self.tabs[i].scene.document.get_entity(h).is_some())
                .collect(),
            // Highest handle among the selectable wires of the current space —
            // handles are handed out monotonically, so that is the most
            // recently created object.
            "L" | "LAST" => self.tabs[i]
                .scene
                .entity_wires()
                .iter()
                .filter_map(|w| crate::scene::Scene::handle_from_wire_name(&w.name))
                .max_by_key(|h| h.value())
                .into_iter()
                .collect(),
            _ => return None,
        };
        if add.is_empty() {
            self.command_line.push_info(crate::t!(match kw.as_str() {
                "P" | "PREVIOUS" => "No previous selection set.",
                "ALL" => "Nothing to select.",
                _ => "No last object.",
            }).as_ref());
            return Some(Task::none());
        }
        let count = add.len();
        for h in add {
            self.tabs[i].scene.select_entity(h, false);
        }
        self.command_line
            .push_info(crate::tf!("{count} object(s) added to selection.").as_ref());
        self.refresh_properties();
        let handles: Vec<Handle> = self.tabs[i]
            .scene
            .selected_entities()
            .into_iter()
            .map(|(h, _)| h)
            .collect();
        Some(self.feed_command(StepInput::SelectionComplete(handles)))
    }

    pub(super) fn feed_active_cmd(&mut self, token: &str) -> Task<Message> {
        let i = self.active_tab;
        // Object-pick step: the token is a handle (as returned by `query`).
        if self.tabs[i]
            .active_cmd
            .as_ref()
            .is_some_and(|c| c.needs_entity_pick())
        {
            // Option keywords take precedence over the handle reading —
            // "F"/"C"/"E" are valid hex, but during TRIM/EXTEND they are the
            // Fence/Crossing/Edge options (#336). Only an unconsumed token
            // falls through to the handle interpretation.
            let consumed = self.tabs[i]
                .active_cmd
                .as_mut()
                .and_then(|c| c.on_text_input(token));
            if let Some(r) = consumed {
                return self.apply_cmd_result(r);
            }
            let accepts_points = self.tabs[i]
                .active_cmd
                .as_ref()
                .is_some_and(|command| command.entity_pick_accepts_points());
            if accepts_points {
                if let Some((coord, kind)) = super::helpers::parse_coord(token) {
                    let ucs = self.tabs[i].active_ucs.clone();
                    let wcs = match (
                        matches!(kind, super::helpers::CoordKind::Relative),
                        self.last_point,
                    ) {
                        (true, Some(base)) => {
                            base + match &ucs {
                                Some(value) => super::helpers::ucs_rotate_vec(coord, value),
                                None => coord,
                            }
                        }
                        _ => match &ucs {
                            Some(value) => super::helpers::ucs_to_wcs(coord, value),
                            None => coord,
                        },
                    };
                    if self.command_point_allowed(i, wcs) {
                        self.last_point = Some(wcs);
                        self.push_ucs_to_cmd(i);
                        return self.feed_command(StepInput::Point(wcs));
                    }
                    return Task::none();
                }
            }
            if let Ok(v) = u64::from_str_radix(token.trim_start_matches("0x"), 16) {
                let handle = Handle::new(v);
                let pt = self.tabs[i]
                    .scene
                    .document
                    .get_entity(handle)
                    .map(|e| {
                        let bb = e.as_entity().bounding_box();
                        glam::Vec3::new(
                            ((bb.min.x + bb.max.x) * 0.5) as f32,
                            ((bb.min.y + bb.max.y) * 0.5) as f32,
                            0.0,
                        )
                    })
                    .unwrap_or(glam::Vec3::ZERO);
                return self.feed_command(StepInput::EntityPick(handle, pt.as_dvec3()));
            }
            return Task::none();
        }
        let is_mtp = token.trim_start_matches('_').eq_ignore_ascii_case("MTP")
            || token.trim_start_matches('_').eq_ignore_ascii_case("M2P");
        if is_mtp {
            let is_point_step = !self.tabs[i]
                .active_cmd
                .as_ref()
                .map(|c| c.input_kind().wants_text())
                .unwrap_or(true)
                || self.tabs[i]
                    .active_cmd
                    .as_ref()
                    .map(|c| c.point_step_accepts_keywords())
                    .unwrap_or(false);
            let not_entity_pick = !self.tabs[i]
                .active_cmd
                .as_ref()
                .map(|c| c.needs_entity_pick())
                .unwrap_or(false);
            if is_point_step && not_entity_pick {
                self.start_mtp_modifier(i);
                return Task::none();
            }
        }
        if let Some((coord, kind)) = super::helpers::parse_coord(token) {
            // Match the GUI command line: typed coordinates are in the active
            // UCS (relative offsets are rotated by the UCS axes), so a multi-
            // token `LINE 0,0 10,10` under a rotated UCS lands correctly.
            let ucs = self.tabs[i].active_ucs.clone();
            let wcs = match (
                matches!(kind, super::helpers::CoordKind::Relative),
                self.last_point,
            ) {
                (true, Some(base)) => {
                    base + match &ucs {
                        Some(u) => super::helpers::ucs_rotate_vec(coord, u),
                        None => coord,
                    }
                }
                _ => match &ucs {
                    Some(u) => super::helpers::ucs_to_wcs(coord, u),
                    None => coord,
                },
            };
            if !self.command_point_allowed(i, wcs) {
                return Task::none();
            }
            self.last_point = Some(wcs);
            self.push_ucs_to_cmd(i);
            return self.feed_command(StepInput::Point(wcs));
        } else {
            return self.feed_command(StepInput::Text(token.to_string()));
        }
    }

    /// Applies one command result, then — when that result ended the active
    /// command — drops the selection. Editing tools (MOVE, COPY, ROTATE, …) and
    /// every other interactive command leave nothing selected once they finish,
    /// so a follow-up edit doesn't silently reuse the previous working set.
    ///
    /// `Relaunch`/`Dispatch` are excepted: they end the front-end command only
    /// to immediately start another and hand it a deliberate selection (the
    /// pick-first selector relaunching MOVE on the picked set works this way).
    /// Pure-selection commands (SELECTALL, QSELECT, …) run without an active
    /// command, so `was_active` is false and their selection is preserved.
    pub(super) fn apply_cmd_result(&mut self, mut result: CmdResult) -> Task<Message> {
        let i = self.active_tab;
        if let CmdResult::ReturnPoint(pt) = result {
            self.tabs[i].scene.clear_preview_wire();
            if let Some(mut suspended) = self.tabs[i].suspended_cmd.take() {
                self.last_point = Some(pt);
                let next_res = suspended.on_point(pt);
                self.tabs[i].active_cmd = Some(suspended);
                result = next_res;
            } else {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                return Task::none();
            }
        }
        let settings = self.tabs[self.active_tab]
            .active_cmd
            .as_ref()
            .and_then(|command| command.sketch_settings());
        if let Some((sketch_type, increment, tolerance)) = settings {
            let tab = &mut self.tabs[self.active_tab];
            let changed = tab.scene.document.header.sketch_type != sketch_type
                || (tab.scene.document.header.sketch_increment - increment).abs() > f64::EPSILON
                || (tab.scene.document.header.sketch_tolerance - tolerance).abs()
                    > f64::EPSILON;
            if changed {
                crate::io::set_sketch_settings(
                    &mut tab.scene.document,
                    sketch_type,
                    increment,
                    tolerance,
                );
                tab.dirty = true;
            }
        }
        let mline_settings = self.tabs[self.active_tab]
            .active_cmd
            .as_ref()
            .and_then(|command| command.mline_settings());
        if let Some((scale, justification, style_name, style_handle)) = mline_settings {
            let tab = &mut self.tabs[self.active_tab];
            let header = &mut tab.scene.document.header;
            let style_handle = style_handle.unwrap_or(acadrust::Handle::NULL);
            let changed = (header.multiline_scale - scale).abs() > f64::EPSILON
                || header.multiline_justification != justification
                || !header.multiline_style.eq_ignore_ascii_case(&style_name)
                || header.current_multiline_style_handle != style_handle;
            if changed {
                header.multiline_scale = scale;
                header.multiline_justification = justification;
                header.multiline_style = style_name;
                header.current_multiline_style_handle = style_handle;
                tab.dirty = true;
            }
        }
        let was_active = self.tabs[self.active_tab].active_cmd.is_some();
        let preserve_selection = matches!(
            &result,
            CmdResult::Relaunch(..)
                | CmdResult::Dispatch(..)
                | CmdResult::SolidEdgeBlend { .. }
                | CmdResult::SolidSubtract { .. }
                | CmdResult::SliceEntities { .. }
                | CmdResult::SliceSurfaceEntities { .. }
        );
        let task = self.apply_cmd_result_inner(result);
        let i = self.active_tab;
        let preview_hidden = self.tabs[i]
            .active_cmd
            .as_ref()
            .map(|command| command.preview_hidden_handles().to_vec())
            .unwrap_or_default();
        self.tabs[i]
            .scene
            .set_command_preview_hidden(&preview_hidden);
        if was_active
            && !preserve_selection
            && self.tabs[i].active_cmd.is_none()
            && !self.tabs[i].scene.selected.is_empty()
        {
            // Remember the working set for the "Previous" selection keyword
            // (#426) before dropping it.
            self.tabs[i].prev_selection = self.tabs[i].scene.selected.iter().copied().collect();
            self.tabs[i].scene.deselect_all();
            self.refresh_properties();
        }
        // A command just ended (any terminal result) — if it was the draw
        // command an ADDSELECTED launched, revert the template-property override
        // so CLAYER / CECOLOR / … are left unchanged (#239). No-op otherwise.
        if was_active && self.tabs[i].active_cmd.is_none() {
            self.tabs[i].scene.set_hover_highlight(None);
            self.command_line.set_step_options(Vec::new());
            self.restore_add_selected_defaults();
        }
        task
    }

    /// Resolve the cell under `click` on table `handle` (or any table in the drawing
    /// if `handle` is `Handle::NULL`), arm the cell indicator, and launch the cell
    /// editor unless the cell's content is locked. Shared by the double-click shortcut
    /// and the TABLEDIT point pick so both agree on grid coordinates and editor setup.
    pub(crate) fn begin_table_cell_edit(
        &mut self,
        i: usize,
        handle: acadrust::Handle,
        click: glam::DVec3,
    ) -> crate::modules::annotate::table_cmd::TableCellEditStart {
        use crate::modules::annotate::table_cmd::{table_cell_at, TableCellEditStart};
        let target = if handle != acadrust::Handle::NULL {
            self.tabs[i]
                .scene
                .document
                .get_entity(handle)
                .and_then(|entity| match entity {
                    acadrust::EntityType::Table(table) => Some((handle, table.clone())),
                    _ => None,
                })
        } else {
            // Find all tables whose grid contains `click`.
            // Iterating document.entities() visits entities in draw order;
            // taking the last match selects the table on top if they overlap.
            let mut matched = None;
            for entity in self.tabs[i].scene.document.entities() {
                if let acadrust::EntityType::Table(table) = entity {
                    let h = table.common.handle;
                    let style = table.table_style_handle.and_then(|style_handle| {
                        self.tabs[i]
                            .scene
                            .document
                            .objects
                            .get(&style_handle)
                            .and_then(|object| match object {
                                acadrust::objects::ObjectType::TableStyle(style) => Some(style),
                                _ => None,
                            })
                    });
                    if table_cell_at(table, style, click).is_some() {
                        matched = Some((h, table.clone()));
                    }
                }
            }
            matched
        };
        let Some((handle, table)) = target else {
            return TableCellEditStart::NoCell;
        };
        let style = table.table_style_handle.and_then(|style_handle| {
            self.tabs[i]
                .scene
                .document
                .objects
                .get(&style_handle)
                .and_then(|object| match object {
                    acadrust::objects::ObjectType::TableStyle(style) => Some(style),
                    _ => None,
                })
        });
        let Some(hit) = table_cell_at(&table, style, click) else {
            return TableCellEditStart::NoCell;
        };
        // Arm the Properties cell indicator whether or not the cell turns
        // out to be editable (matches the double-click behavior).
        let index = hit.index(&table);
        self.tabs[i].properties.prop_vertex = index;
        self.tabs[i].properties.prop_vertex_indicator_active = true;
        crate::entities::table::set_prop_current_cell(index);
        self.refresh_properties();
        if hit.locked {
            return TableCellEditStart::LockedCell;
        }
        let command = crate::modules::annotate::table_cmd::TableCellEditCommand::new(
            handle, &table, hit.row, hit.column,
        );
        self.command_line
            .push_info(&crate::command::CadCommand::prompt(&command));
        self.tabs[i].active_cmd = Some(Box::new(command));
        TableCellEditStart::Started
    }

    /// Removes and re-solves the first conflicting constraint in the active scope.
    pub(super) fn resolve_one_sketch_conflict(&mut self) {
        let i = self.active_tab;
        let scope = self.tabs[i].current_sketch_scope();
        let Some(set) = self.tabs[i].scene.sketch_constraint_set(scope) else { return };
        let Some(&(id, _kind)) = set.conflicts.first() else { return };
        let Some(constraint) = set.get(id) else { return };
        let touched: Vec<Handle> = constraint.refs.iter().map(|r| r.entity).collect();
        let label = "Remove conflicting constraint";

        let constraints_before = set.clone();
        let pending = self.begin_undo(i, label, touched.len(), true);
        self.tabs[i]
            .scene
            .record_undo_sketch_constraints_before(scope, constraints_before);
        self.tabs[i].scene.sketch_constraint_set_mut(scope).remove(id);
        let changes: Vec<(Handle, crate::scene::ChangeKind)> =
            touched.into_iter().map(|h| (h, crate::scene::ChangeKind::Modified)).collect();
        self.tabs[i].scene.bump_entities(&changes);
        if let Some(pd) = pending {
            self.commit_undo_delta(i, pd);
        }
    }

    /// Rebuilds the active tab's `Scene::named_parameters` from the
    /// editor's working buffer and re-solves dependent constraints.
    pub(super) fn apply_named_parameter_editor_rows(&mut self) {
        let i = self.active_tab;
        // A name shared by more than one row can't be resolved by picking
        // one arbitrarily (`ParameterTable::set` would just let the last
        // one silently win) -- refuse every row sharing that name up front,
        // same as `named_parameters::preview`'s live check.
        let duplicates = crate::ui::window::named_parameters::duplicate_name_rows(&self.named_parameter_editor_rows);
        let mut table = crate::scene::named_parameters::ParameterTable::new();
        let mut failed = 0usize;
        for (idx, row) in self.named_parameter_editor_rows.iter().enumerate() {
            let name = row.name.trim();
            if name.is_empty() || duplicates.contains(&idx) {
                continue;
            }
            if let Err(e) = table.set(name, row.formula.trim()) {
                self.command_line.push_error(crate::tf!("Parameter '{}': {}", name, e).as_ref());
                failed += 1;
            }
        }
        if !duplicates.is_empty() {
            self.command_line.push_error(crate::tf!("{} row(s) skipped: duplicate parameter name.", duplicates.len()).as_ref());
            failed += duplicates.len();
        }
        let param_count = table.len();

        // The whole table just changed, not one isolated value, so there is
        // no cheaper "which handles actually moved" test worth doing here —
        // re-solve every scope with a constraint driven by *any* named
        // parameter (mirrors `solve_scope`'s own "full rebuild, not
        // incremental" philosophy).
        let touched: Vec<Handle> = self.tabs[i]
            .scene
            .sketch_constraints
            .iter()
            .flat_map(|set| set.constraints.iter())
            .filter(|c| c.enabled && matches!(c.driving_param, Some(crate::scene::named_parameters::DrivingValue::Named(_))))
            .flat_map(|c| c.refs.iter().map(|r| r.entity))
            .collect();

        let pending = self.begin_undo(i, "Apply named parameters", touched.len(), true);
        self.tabs[i].scene.record_undo_named_parameters_before();
        self.tabs[i].scene.named_parameters = table;
        self.tabs[i].dirty = true;
        if !touched.is_empty() {
            let changes: Vec<(Handle, crate::scene::ChangeKind)> =
                touched.into_iter().map(|h| (h, crate::scene::ChangeKind::Modified)).collect();
            self.tabs[i].scene.bump_entities(&changes);
        }
        if let Some(pd) = pending {
            self.commit_undo_delta(i, pd);
        }
        if failed == 0 {
            self.command_line.push_info(crate::tf!("{} parameter(s) applied.", param_count).as_ref());
        }
    }

    /// Re-solves every entity touched by an enabled constraint driven by
    /// `name` — the targeted, single-row counterpart to
    /// `apply_named_parameter_editor_rows`'s "re-solve what it affects": an
    /// inline Properties-panel edit changes one parameter, not the whole
    /// table, so unlike that whole-table Apply this can cheaply scope the
    /// re-solve to just the entities that actually reference it.
    fn resolve_named_parameter_edit(&mut self, i: usize, name: &str) {
        let touched: Vec<Handle> = self.tabs[i]
            .scene
            .sketch_constraints
            .iter()
            .flat_map(|set| set.constraints.iter())
            .filter(|c| {
                c.enabled
                    && matches!(&c.driving_param, Some(crate::scene::named_parameters::DrivingValue::Named(n)) if n == name)
            })
            .flat_map(|c| c.refs.iter().map(|r| r.entity))
            .collect();
        self.tabs[i].dirty = true;
        if touched.is_empty() {
            return;
        }
        let changes: Vec<(Handle, crate::scene::ChangeKind)> =
            touched.into_iter().map(|h| (h, crate::scene::ChangeKind::Modified)).collect();
        self.tabs[i].scene.bump_entities(&changes);
    }

    /// Commits one field of one Parameters-section row (Properties panel) —
    /// the per-row, commit-on-submit counterpart to
    /// `apply_named_parameter_editor_rows`'s whole-table Apply. A Formula
    /// edit is a plain redefine (`ParameterTable::set` on the existing
    /// name); a Name edit is a remove-then-set (there's no rename primitive
    /// — `ParameterTable` upserts by name), restoring the old name if the
    /// new one fails to validate so nothing is silently lost. Either way
    /// this only re-solves what actually depends on this one parameter —
    /// no "duplicate name" scan across the whole table is needed the way
    /// the buffered modal Apply needs one, since every row here is always
    /// already a real, distinct table entry.
    pub(super) fn on_prop_param_commit(
        &mut self,
        index: usize,
        field: crate::ui::window::named_parameters::ParamField,
    ) -> Task<Message> {
        use crate::ui::properties::FieldKey;
        use crate::ui::window::named_parameters::ParamField;
        let i = self.active_tab;
        let key = FieldKey::Param(index, field);
        self.tabs[i].properties.active_field = None;
        let Some(typed) = self.tabs[i].properties.edit_buf.remove(&key) else {
            return Task::none();
        };
        let typed = typed.trim().to_string();
        let Some(current) = self.tabs[i].scene.named_parameters().iter().nth(index).cloned() else {
            self.refresh_properties();
            return Task::none();
        };

        match field {
            ParamField::Formula if typed.is_empty() || typed == current.source => {
                self.refresh_properties();
                return Task::none();
            }
            ParamField::Name if typed.is_empty() || typed == current.name => {
                self.refresh_properties();
                return Task::none();
            }
            ParamField::Name if self.tabs[i].scene.named_parameters().contains(&typed) => {
                self.command_line.push_error(crate::tf!("Parameter '{}' already exists.", typed).as_ref());
                self.refresh_properties();
                return Task::none();
            }
            _ => {}
        }

        let pending = self.begin_undo(i, "Edit named parameter", 0, true);
        self.tabs[i].scene.record_undo_named_parameters_before();

        let (result, resolve_name) = match field {
            ParamField::Formula =>
                (self.tabs[i].scene.named_parameters_mut().set(&current.name, &typed), current.name.clone()),
            ParamField::Name => {
                self.tabs[i].scene.named_parameters_mut().remove(&current.name);
                let outcome = self.tabs[i].scene.named_parameters_mut().set(&typed, &current.source);
                if outcome.is_err() {
                    let _ = self.tabs[i].scene.named_parameters_mut().set(&current.name, &current.source);
                }
                (outcome, typed.clone())
            }
        };

        if let Err(e) = result {
            self.tabs[i].scene.take_undo_recording();
            self.command_line.push_error(crate::tf!("Parameter '{}': {}", current.name, e).as_ref());
            self.refresh_properties();
            return Task::none();
        }

        if field == ParamField::Name {
            let affected: Vec<usize> = self.tabs[i]
                .scene
                .sketch_constraints
                .iter()
                .enumerate()
                .filter_map(|(index, set)| {
                    set.constraints
                        .iter()
                        .any(|constraint| {
                            matches!(&constraint.driving_param, Some(crate::scene::named_parameters::DrivingValue::Named(name)) if name == &current.name)
                        })
                        .then_some(index)
                })
                .collect();
            for set_index in affected {
                let scope = self.tabs[i].scene.sketch_constraints[set_index].scope;
                let before = self.tabs[i].scene.sketch_constraints[set_index].clone();
                self.tabs[i].scene.record_undo_sketch_constraints_before(scope, before);
                for constraint in &mut self.tabs[i].scene.sketch_constraints[set_index].constraints {
                    if let Some(crate::scene::named_parameters::DrivingValue::Named(name)) = &mut constraint.driving_param {
                        if name == &current.name {
                            *name = typed.clone();
                        }
                    }
                }
            }
        }
        self.resolve_named_parameter_edit(i, &resolve_name);
        if let Some(pd) = pending {
            self.commit_undo_delta(i, pd);
        }
        self.refresh_properties();
        Task::none()
    }

    /// Removes Parameters-section row `index` immediately. Any
    /// constraint that referenced it gets the same "undefined reference"
    /// resolve-failure treatment a formula's own bad reference already gets
    /// (`build_constraint`) — re-solving surfaces that rather than needing
    /// special-case handling here.
    pub(super) fn on_prop_param_delete(&mut self, index: usize) -> Task<Message> {
        let i = self.active_tab;
        let Some(name) = self.tabs[i].scene.named_parameters().iter().nth(index).map(|p| p.name.clone()) else {
            return Task::none();
        };
        let pending = self.begin_undo(i, "Delete named parameter", 0, true);
        self.tabs[i].scene.record_undo_named_parameters_before();
        self.tabs[i].scene.named_parameters_mut().remove(&name);
        self.resolve_named_parameter_edit(i, &name);
        if let Some(pd) = pending {
            self.commit_undo_delta(i, pd);
        }
        self.refresh_properties();
        Task::none()
    }

    /// The Parameters section's "+ Add parameter" row: appends a fresh,
    /// uniquely-named parameter (`param1`, `param2`, …) the user then
    /// renames/redefines inline via `on_prop_param_commit`. Defaults to `1`,
    /// not `0`: renaming this onto a name an existing Distance/Radius
    /// constraint already references (unusual, but reachable — define
    /// first, wire up the constraint's reference later) would otherwise
    /// briefly collapse that geometry to a zero-length/zero-radius
    /// degenerate state, which is a genuine numerical singularity for a
    /// point-to-point distance constraint to grow back out of (no defined
    /// direction to separate two exactly-coincident points from). `1` never
    /// hits that.
    pub(super) fn on_prop_param_add_new(&mut self) -> Task<Message> {
        let i = self.active_tab;
        let mut n = 1usize;
        let name = loop {
            let candidate = format!("param{n}");
            if !self.tabs[i].scene.named_parameters().contains(&candidate) {
                break candidate;
            }
            n += 1;
        };
        let pending = self.begin_undo(i, "Add named parameter", 0, true);
        self.tabs[i].scene.record_undo_named_parameters_before();
        let _ = self.tabs[i].scene.named_parameters_mut().set(&name, "1");
        self.tabs[i].dirty = true;
        if let Some(pd) = pending {
            self.commit_undo_delta(i, pd);
        }
        self.refresh_properties();
        Task::none()
    }

    pub(in crate::app) fn start_mtp_modifier(&mut self, i: usize) {
        let parent = self.tabs[i].active_cmd.take();
        self.tabs[i].suspended_cmd = parent;
        self.tabs[i].scene.clear_preview_wire();
        let cmd = crate::command::Mid2PointCommand::new();
        let prompt = crate::command::CadCommand::prompt(&cmd);
        self.tabs[i].active_cmd = Some(Box::new(cmd));
        self.command_line.push_info(&prompt);
        self.command_line.set_step_options(Vec::new());
        self.refresh_active_cmd_preview(i);
    }

    /// Apply a command replacement without deleting a one-to-one entity edit.
    /// Splits and entity-type conversions still allocate replacement identities.
    fn replace_command_entity(
        &mut self,
        tab: usize,
        handle: Handle,
        mut entities: Vec<acadrust::EntityType>,
    ) -> Vec<Handle> {
        let same_type = entities.len() == 1 && self.tabs[tab].scene.document.get_entity(handle)
            .is_some_and(|original| std::mem::discriminant(original) == std::mem::discriminant(&entities[0]));
        let handles = if same_type {
            let mut entity = entities.pop().expect("one replacement");
            entity.common_mut().handle = handle;
            // Scene::update_entity also retains the live owning block and
            // refreshes dependent render caches without erase notifications.
            if self.tabs[tab].scene.update_entity(entity) { vec![handle] } else { Vec::new() }
        } else {
            let owner = self.tabs[tab].scene.document.get_entity(handle).map(|entity| entity.common().owner_handle);
            self.tabs[tab].scene.erase_entities(&[handle]);
            entities.into_iter().map(|mut entity| {
                entity.common_mut().handle = Handle::NULL;
                if let Some(owner) = owner { entity.common_mut().owner_handle = owner; }
                self.tabs[tab].scene.add_entity(entity)
            }).collect()
        };
        for &updated in &handles {
            if matches!(self.tabs[tab].scene.document.get_entity(updated), Some(acadrust::EntityType::Dimension(_))) {
                self.tabs[tab].scene.invalidate_dim_block_recorded(updated);
            }
        }
        handles
    }

    fn apply_pedit_result(
        &mut self,
        tab: usize,
        handle: Handle,
        op: crate::modules::draw::modify::pedit::PeditOp,
    ) -> Task<Message> {
        use crate::modules::draw::modify::pedit::{apply_pedit, convert_to_polyline, PeditOp};

        if !matches!(
            &op,
            PeditOp::Multiple(_, _) | PeditOp::JoinSelection(_, _, _)
        )
            && self.reject_locked_edit(tab, handle)
        {
            return Task::none();
        }
        match &op {
            PeditOp::JoinSelection(handles, fuzz, kind) => {
                let mut available = handles
                    .iter()
                    .filter_map(|handle| {
                        if self.tabs[tab].scene.is_layer_locked(*handle) {
                            return None;
                        }
                        self.tabs[tab]
                            .scene
                            .document
                            .get_entity(*handle)
                            .cloned()
                            .map(|entity| (*handle, entity))
                    })
                    .collect::<Vec<_>>();
                let connector_distance = crate::modules::draw::modify::pedit::selection_connector_distance(&available, *fuzz);
                let mut changes = Vec::new();
                while !available.is_empty() {
                    let (source_handle, source) = available.remove(0);
                    let candidates = available
                        .iter()
                        .map(|(handle, entity)| (*handle, entity))
                        .collect::<Vec<_>>();
                    if let Some((mut result, consumed)) =
                        crate::modules::draw::modify::pedit::join_selection_extend(
                            &source,
                            &candidates,
                            *fuzz,
                            *kind,
                            connector_distance,
                        )
                    {
                        *result.common_mut() = source.common().clone();
                        available.retain(|(handle, _)| !consumed.contains(handle));
                        changes.push((source_handle, result, consumed));
                    }
                }
                if !changes.is_empty() {
                    self.push_undo_snapshot(tab, "PEDIT");
                    for (source, replacement, consumed) in changes {
                        self.tabs[tab].scene.erase_entities(&consumed);
                        self.tabs[tab].scene.update_entity(replacement.clone());
                        if let Some(command) = self.tabs[tab].active_cmd.as_mut() {
                            for old in consumed {
                                command.on_entity_replaced(old, &[source]);
                            }
                            command.inject_picked_entity(replacement);
                        }
                    }
                    if let Some(command) = self.tabs[tab].active_cmd.as_mut() {
                        command.on_pedit_applied();
                    }
                    self.tabs[tab].dirty = true;
                    self.refresh_properties();
                }
            }
            PeditOp::Multiple(handles, operation) => {
                let replacements: Vec<_> = handles
                    .iter()
                    .filter(|handle| !self.tabs[tab].scene.is_layer_locked(**handle))
                    .filter_map(|handle| {
                        let original = self.tabs[tab].scene.document.get_entity(*handle)?;
                        if matches!(operation.as_ref(), PeditOp::ConvertToPolyline) {
                            convert_to_polyline(original)
                                .map(|replacement| (*handle, replacement, true))
                        } else {
                            let mut replacement = original.clone();
                            apply_pedit(&mut replacement, operation)
                                .then_some((*handle, replacement, false))
                        }
                    })
                    .collect();
                if replacements.is_empty() {
                    return Task::none();
                }
                self.push_undo_snapshot(tab, "PEDIT");
                for (handle, replacement, converted) in replacements {
                    let updated_handle = if converted {
                        self.tabs[tab].scene.erase_entities(&[handle]);
                        let new_handle = self.tabs[tab].scene.add_entity(replacement);
                        if let Some(command) = self.tabs[tab].active_cmd.as_mut() {
                            command.on_entity_replaced(handle, &[new_handle]);
                        }
                        new_handle
                    } else {
                        if let Some(entity) = self.tabs[tab].scene.document.get_entity_mut(handle) {
                            *entity = replacement;
                        }
                        self.tabs[tab].scene.refresh_fill_model(handle);
                        self.tabs[tab]
                            .scene
                            .bump_entities(&[(handle, crate::scene::ChangeKind::Modified)]);
                        handle
                    };
                    let updated = self.tabs[tab]
                        .scene
                        .document
                        .get_entity(updated_handle)
                        .cloned();
                    if let (Some(command), Some(entity)) =
                        (self.tabs[tab].active_cmd.as_mut(), updated)
                    {
                        command.inject_picked_entity(entity);
                    }
                }
                if let Some(command) = self.tabs[tab].active_cmd.as_mut() {
                    command.on_pedit_applied();
                }
                self.tabs[tab].dirty = true;
                self.refresh_properties();
            }
            PeditOp::VertexRange { first, last, split } => {
                let pieces = self.tabs[tab]
                    .scene
                    .document
                    .get_entity(handle)
                    .and_then(|entity| {
                        crate::modules::draw::modify::pedit::edit_vertex_range(
                            entity, *first, *last, *split,
                        )
                    });
                if let Some(mut pieces) = pieces {
                    self.push_undo_snapshot(tab, "PEDIT");
                    let source = pieces.remove(0);
                    self.tabs[tab].scene.update_entity(source);
                    for mut piece in pieces {
                        piece.common_mut().handle = Handle::NULL;
                        self.tabs[tab].scene.add_entity(piece);
                    }
                    let updated = self.tabs[tab].scene.document.get_entity(handle).cloned();
                    if let Some(command) = self.tabs[tab].active_cmd.as_mut() {
                        if let Some(entity) = updated {
                            command.inject_picked_entity(entity);
                        }
                        command.on_pedit_applied();
                    }
                    self.tabs[tab].dirty = true;
                    self.refresh_properties();
                } else {
                    self.command_line.push_error("PEDIT: invalid vertex range.");
                }
            }
            PeditOp::ConvertToPolyline => {
                let converted = self.tabs[tab]
                    .scene
                    .document
                    .get_entity(handle)
                    .and_then(convert_to_polyline);
                match converted {
                    Some(polyline) => {
                        return self.apply_cmd_result(CmdResult::ReplaceEntity(
                            handle,
                            vec![polyline],
                        ));
                    }
                    None => self.command_line.push_error(
                        crate::t!("PEDIT: cannot convert this entity.").as_ref(),
                    ),
                }
            }
            _ => {
                self.push_undo_snapshot(tab, "PEDIT");
                let changed = self.tabs[tab]
                    .scene
                    .document
                    .get_entity_mut(handle)
                    .map(|entity| apply_pedit(entity, &op))
                    .unwrap_or(false);
                if changed {
                    let updated = self.tabs[tab].scene.document.get_entity(handle).cloned();
                    if let Some(command) = self.tabs[tab].active_cmd.as_mut() {
                        if let Some(entity) = updated {
                            command.inject_picked_entity(entity);
                        }
                        command.on_pedit_applied();
                    }
                    self.tabs[tab].dirty = true;
                    self.tabs[tab].scene.refresh_fill_model(handle);
                    self.tabs[tab]
                        .scene
                        .bump_entities(&[(handle, crate::scene::ChangeKind::Modified)]);
                    self.command_line
                        .push_output(crate::t!("PEDIT: applied.").as_ref());
                    self.refresh_properties();
                } else {
                    self.discard_last_undo_entry(tab);
                    self.command_line.push_error(
                        crate::t!("PEDIT: operation not applicable to this entity.").as_ref(),
                    );
                }
            }
        }
        if let Some(prompt) = self.tabs[tab].active_cmd.as_ref().map(|command| command.prompt()) {
            self.command_line.push_info(&prompt);
        }
        Task::none()
    }

    fn apply_cmd_result_inner(&mut self, result: CmdResult) -> Task<Message> {
        let i = self.active_tab;
        if let Some(bind) = self.tabs[i].active_cmd.as_ref().and_then(|command| command.nested_copy_bind_setting()) {
            if self.ncopy_bind != bind {
                self.ncopy_bind = bind;
                self.persist_settings_if_changed();
            }
        }
        let preserve_commit_style = self.tabs[i].active_cmd.as_ref()
            .is_some_and(|command| command.preserve_commit_style());
        let preserve_commit_layer = self.tabs[i]
        .active_cmd
        .as_ref()
        .is_some_and(|command| command.preserve_commit_layer());
        match result {
            CmdResult::NeedPoint => {
                // ATTEDIT finished its entity pick: hand the chosen block off to
                // the attribute editor dialog and end the command (open_attribute
                // _editor reports "no attributes" / "select a block" as needed).
                let attedit_handle = self.tabs[i]
                    .active_cmd
                    .as_ref()
                    .and_then(|c| c.attedit_pending_handle());
                if let Some(ins_handle) = attedit_handle {
                    self.tabs[i].active_cmd = None;
                    self.command_line.set_step_options(Vec::new());
                    self.open_attribute_editor(ins_handle);
                    return Task::none();
                }
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
                let opts = self.tabs[i]
                    .active_cmd
                    .as_ref()
                    .map(|c| c.options())
                    .unwrap_or_default();
                self.command_line.set_step_options(opts);
                if !self.tabs[i]
                    .active_cmd
                    .as_ref()
                    .is_some_and(|c| c.entity_pick_highlights_hover())
                {
                    self.tabs[i].scene.set_hover_highlight(None);
                }
                // The command may have advanced to a step with a different
                // dynamic-input shape (e.g. FILLET object-pick → radius entry).
                // Rebuild the fields now so the matching box appears immediately
                // and typed digits land in it rather than the command line,
                // instead of waiting for the next cursor move to resync.
                self.sync_dyn_fields();
                self.refresh_area_preview(i);
            }
            CmdResult::Preview(wire) => {
                self.tabs[i].scene.set_preview_wires(vec![wire]);
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
            }
            CmdResult::InterimWire(wire) => {
                self.tabs[i].scene.set_interim_wire(wire);
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
            }
            CmdResult::CommitEntity(entity) => {
                let source_handle = entity.common().handle;
                if !source_handle.is_null()
                    && self.tabs[i]
                        .scene
                        .document
                        .get_entity(source_handle)
                        .is_some()
                    && self.reject_locked_edit(i, source_handle)
                {
                    return Task::none();
                }
                // A line/arc drawn by a repeating command advances the ARC_CONT
                // continuation anchor, so ending one run and launching another
                // keeps continuing from the last segment (mirrors the
                // CommitAndExit arm). Non-continuable repeats (point/ray)
                // leave the anchor untouched. (#327)
                if matches!(
                    entity,
                    acadrust::EntityType::Line(_)
                        | acadrust::EntityType::Arc(_)
                        | acadrust::EntityType::LwPolyline(_)
                        | acadrust::EntityType::Polyline2D(_)
                ) {
                    self.update_cont_anchor(&entity);
                }
                let label = self.history_label_from_active_cmd(i, "ENTITY");
                // Ordinary drawables, viewports and raster images use targeted
                // entity/object deltas. Block sentinels and novel layers retain
                // the structure snapshot fallback.
                let delta_safe = self.delta_add_safe(i, &entity);
                let pending = self.begin_undo(i, label, 1, delta_safe);
                let is_associative_dimension = matches!(
                    entity,
                    acadrust::EntityType::Dimension(
                        acadrust::entities::Dimension::Linear(_)
                            | acadrust::entities::Dimension::Aligned(_)
                    )
                );
                let association_enabled =
                    self.tabs[i].scene.document.header.dimension_associativity == 2;
                let committed = if preserve_commit_layer {
                    self.commit_entity_handle_preserve_layer(entity)
                } else {
                    self.commit_entity_handle(entity)
                };
                if is_associative_dimension && association_enabled {
                    if let Some(handle) = committed {
                        let sources = self.infer_dimension_sources_guarded(i, handle);
                        self.tabs[i]
                            .scene
                            .attach_dimension_association(handle, sources);
                    }
                }
                self.tabs[i].dirty = true;
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::CommitEntities(mut entities) => {
                let locked_source = entities.iter().find_map(|entity| {
                    let handle = entity.common().handle;
                    (!handle.is_null()
                        && self.tabs[i].scene.document.get_entity(handle).is_some()
                        && self.tabs[i].scene.is_layer_locked(handle))
                    .then_some(handle)
                });
                if let Some(handle) = locked_source {
                    self.reject_locked_edit(i, handle);
                    return Task::none();
                }
                let label = self.history_label_from_active_cmd(i, "ENTITY");
                let symbol_names = self.tabs[i].active_cmd.as_ref()
                    .and_then(|command| command.nested_copy_symbol_names()).cloned();
                let delta_safe = symbol_names.is_none() && entities
                    .iter()
                    .all(|entity| self.delta_add_safe(i, entity));
                let pending = self.begin_undo(i, label, entities.len(), delta_safe);
                if let Some(names) = symbol_names {
                    let retained = self.tabs[i].scene.document.localize_nested_copy_symbols(&mut entities, &names);
                    if retained > 0 {
                        self.command_line.push_info(&format!("{} copied object(s) retain imported style references whose dependencies cannot be localized.", retained));
                    }
                    self.refresh_layer_panel();
                }
                for entity in entities {
                    if preserve_commit_style {
                        let _ = self.commit_entity_handle_preserve_style(entity);
                    } else if preserve_commit_layer {
                        let _ = self.commit_entity_handle_preserve_layer(entity);
                    } else {
                        self.commit_entity(entity);
                    }
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::CommitEntitiesAndExit(mut entities) => {
                let label = self.history_label_from_active_cmd(i, "ENTITY");
                let symbol_names = self.tabs[i].active_cmd.as_ref()
                    .and_then(|command| command.nested_copy_symbol_names()).cloned();
                let delta_safe = symbol_names.is_none() && entities
                    .iter()
                    .all(|entity| self.delta_add_safe(i, entity));
                let pending = self.begin_undo(i, label, entities.len(), delta_safe);
                if let Some(names) = symbol_names {
                    let retained = self.tabs[i].scene.document.localize_nested_copy_symbols(&mut entities, &names);
                    if retained > 0 {
                        self.command_line.push_info(&format!("{} copied object(s) retain imported style references whose dependencies cannot be localized.", retained));
                    }
                    self.refresh_layer_panel();
                }
                for entity in entities {
                    if preserve_commit_style {
                        let _ = self.commit_entity_handle_preserve_style(entity);
                    } else if preserve_commit_layer {
                        let _ = self.commit_entity_handle_preserve_layer(entity);
                    } else {
                        self.commit_entity(entity);
                    }
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::MviewCreate {
                viewport,
                preserve_view,
            } => {
                let saved_view = preserve_view.then(|| {
                    (
                        viewport.view_target.clone(),
                        viewport.view_direction.clone(),
                        viewport.view_center.clone(),
                        viewport.view_height,
                        viewport.custom_scale,
                        viewport.lens_length,
                        viewport.twist_angle,
                        viewport.status.perspective,
                    )
                });
                let label = self.history_label_from_active_cmd(i, "MVIEW");
                let pending = self.begin_undo(i, label, 1, true);
                let handle = self.commit_entity_handle(
                    acadrust::EntityType::Viewport(viewport),
                );
                if let (Some(handle), Some(saved)) = (handle, saved_view) {
                    if let Some(acadrust::EntityType::Viewport(viewport)) =
                        self.tabs[i].scene.document.get_entity_mut(handle)
                    {
                        viewport.view_target = saved.0;
                        viewport.view_direction = saved.1;
                        viewport.view_center = saved.2;
                        viewport.view_height = saved.3;
                        viewport.custom_scale = saved.4;
                        viewport.lens_length = saved.5;
                        viewport.twist_angle = saved.6;
                        viewport.status.perspective = saved.7;
                    }
                    self.tabs[i].scene.camera_generation += 1;
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                if let Some(pending) = pending {
                    self.commit_undo_delta(i, pending);
                }
            }
            CmdResult::MviewCreateClipped {
                boundary,
                boundary_handle,
            } => {
                if boundary.is_none() {
                    let scene = &self.tabs[i].scene;
                    let valid = scene
                        .entity_belongs_to_current_layout(boundary_handle)
                        && scene
                        .document
                        .get_entity(boundary_handle)
                        .is_some_and(|entity| {
                            match entity {
                                acadrust::EntityType::Circle(_) => true,
                                acadrust::EntityType::Ellipse(ellipse) => ellipse.is_full(),
                                acadrust::EntityType::LwPolyline(polyline) => {
                                    polyline.is_closed
                                }
                                acadrust::EntityType::Polyline(polyline) => {
                                    polyline.is_closed()
                                }
                                acadrust::EntityType::Polyline2D(polyline) => {
                                    polyline.is_closed()
                                }
                                acadrust::EntityType::Polyline3D(polyline) => {
                                    polyline.flags.closed
                                }
                                _ => false,
                            }
                        });
                    if !valid {
                        self.command_line.push_error(
                            crate::t!("MVIEW Object: select a closed paper-space circle, ellipse, or polyline.").as_ref(),
                        );
                        if let Some(prompt) =
                            self.tabs[i].active_cmd.as_ref().map(|command| command.prompt())
                        {
                            self.command_line.push_info(&prompt);
                        }
                        return Task::none();
                    }
                }

                let created_boundary = boundary.is_some();
                let touched = 2;
                let label = self.history_label_from_active_cmd(i, "MVIEW");
                let pending = self.begin_undo(i, label, touched, true);
                let clip_handle = match boundary {
                    Some(mut boundary) => {
                        // A non-rectangular viewport owns a helper boundary
                        // entity through `clip_boundary_handle`. Keep that
                        // helper in the document for DWG compatibility and
                        // stencil clipping, but do not expose it as a separate
                        // selectable polyline.
                        boundary.common_mut().invisible = true;
                        match self.commit_entity_handle(boundary) {
                            Some(handle) => handle,
                            None => {
                                self.tabs[i].active_cmd = None;
                                if let Some(pending) = pending {
                                    self.commit_undo_delta(i, pending);
                                }
                                return Task::none();
                            }
                        }
                    }
                    None => boundary_handle,
                };
                let polygon = self.tabs[i]
                    .scene
                    .clip_boundary_polygon(clip_handle, 0.0);
                let bounds: Option<(f64, f64, f64, f64)> =
                    polygon.iter().fold(None, |bounds, point| {
                        if !point[0].is_finite() || !point[1].is_finite() {
                            return bounds;
                        }
                        Some(match bounds {
                            Some((min_x, min_y, max_x, max_y)) => (
                                min_x.min(point[0] as f64),
                                min_y.min(point[1] as f64),
                                max_x.max(point[0] as f64),
                                max_y.max(point[1] as f64),
                            ),
                            None => (
                                point[0] as f64,
                                point[1] as f64,
                                point[0] as f64,
                                point[1] as f64,
                            ),
                        })
                    });
                let Some((min_x, min_y, max_x, max_y)) = bounds else {
                    self.command_line
                        .push_error(crate::t!("MVIEW: the clipping boundary has no usable area.").as_ref());
                    self.tabs[i].active_cmd = None;
                    if let Some(pending) = pending {
                        self.commit_undo_delta(i, pending);
                    }
                    return Task::none();
                };
                if max_x - min_x < 1e-6 || max_y - min_y < 1e-6 {
                    self.command_line
                        .push_error(crate::t!("MVIEW: the clipping boundary has no usable area.").as_ref());
                    self.tabs[i].active_cmd = None;
                    if let Some(pending) = pending {
                        self.commit_undo_delta(i, pending);
                    }
                    return Task::none();
                }

                let mut viewport = acadrust::entities::Viewport::new();
                viewport.center = acadrust::types::Vector3::new(
                    (min_x + max_x) / 2.0,
                    (min_y + max_y) / 2.0,
                    0.0,
                );
                viewport.width = max_x - min_x;
                viewport.height = max_y - min_y;
                viewport.id = 2;
                viewport.clip_boundary_handle = clip_handle;
                let viewport_handle = self.commit_entity_handle(
                    acadrust::EntityType::Viewport(viewport),
                );
                if let Some(viewport_handle) = viewport_handle {
                    if !created_boundary {
                        let before = self.tabs[i]
                            .scene
                            .document
                            .get_entity(clip_handle)
                            .cloned()
                            .map(std::sync::Arc::new);
                        self.tabs[i]
                            .scene
                            .record_undo_before(clip_handle, before);
                    }
                    if let Some(boundary) =
                        self.tabs[i].scene.document.get_entity_mut(clip_handle)
                    {
                        let common = boundary.common_mut();
                        common.invisible = true;
                        if !common.reactors.contains(&viewport_handle) {
                            common.reactors.push(viewport_handle);
                        }
                    }
                    self.tabs[i].scene.bump_entities(&[(
                        clip_handle,
                        crate::scene::ChangeKind::Modified,
                    )]);
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                if let Some(pending) = pending {
                    self.commit_undo_delta(i, pending);
                }
            }
            CmdResult::WipeoutFromPolyline {
                handle,
                erase_source,
            } => {
                let wipeout = {
                    let scene = &self.tabs[i].scene;
                    scene
                        .entity_belongs_to_active_space(handle)
                        .then(|| scene.document.get_entity(handle))
                        .flatten()
                        .and_then(
                            crate::modules::draw::draw::wipeout::wipeout_from_polyline,
                        )
                };
                if let Some(wipeout) = wipeout {
                    if erase_source {
                        return self.apply_cmd_result(CmdResult::ReplaceMany(
                            vec![(handle, Vec::new())],
                            vec![wipeout],
                        ));
                    }
                    return self.apply_cmd_result(CmdResult::CommitAndExit(wipeout));
                }
                self.command_line.push_error(
                    crate::t!("WIPEOUT Polyline: select a straight, closed, planar 2D polyline with at least 3 non-intersecting vertices.").as_ref(),
                );
                let command =
                    crate::modules::draw::draw::wipeout::WipeoutCommand::new_polyline();
                self.command_line.push_info(
                    &crate::command::CadCommand::prompt(&command),
                );
                self.tabs[i].active_cmd = Some(Box::new(command));
            }
            CmdResult::MviewSwitchLayout(layout) => {
                let task = self.on_layout_switch_preserving_command(layout);
                if let Some(prompt) =
                    self.tabs[i].active_cmd.as_ref().map(|command| command.prompt())
                {
                    self.command_line.push_info(&prompt);
                }
                return task;
            }
            CmdResult::MviewCancelToLayout(layout) => {
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                return self.on_layout_switch(layout);
            }
            CmdResult::TransformSelected(mut handles, transform) => {
                handles.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                if handles.is_empty() {
                    self.tabs[i].active_cmd = None;
                    return Task::none();
                }
                let label = self.history_label_from_active_cmd(i, "MOVE");
                // A move/rotate/scale/mirror mutates only the selected entities
                // (and their baked dimension sub-entities) through
                // transform_entities — always delta-safe.
                let pending = self.begin_undo(i, label, handles.len(), true);
                self.tabs[i].scene.transform_entities(&handles, &transform);
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
                if let Some(p) = pending {
                    self.commit_undo_delta(i, p);
                }
            }
            CmdResult::CopySelected(mut handles, transform) => {
                handles.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                if handles.is_empty() {
                    return Task::none();
                }
                let label = self.history_label_from_active_cmd(i, "COPY");
                // Copying a dimension clones a *D block record, so gate delta on
                // the selection being dimension-free.
                let delta_safe = self.delta_copy_safe(i, &handles);
                let pending = self.begin_undo(i, label, handles.len(), delta_safe);
                let new_handles = self.tabs[i].scene.copy_entities(&handles, &transform);
                self.tabs[i].dirty = true;
                self.tabs[i].scene.deselect_all();
                for h in new_handles {
                    self.tabs[i].scene.select_entity(h, false);
                }
                self.tabs[i].scene.clear_preview_wire();
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
                self.refresh_properties();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::CopyToClipboard { handles, base } => {
                let count = self.copy_entities_to_clipboard(i, &handles, base);
                self.command_line.push_info(crate::tf!(
                    "{} object(s) copied to clipboard.",
                    count
                ).as_ref());
                let prompt = self.tabs[i]
                    .active_cmd
                    .as_ref()
                    .map(|command| command.prompt());
                if let Some(prompt) = prompt {
                    self.command_line.push_info(&prompt);
                }
                self.command_line.set_step_options(
                    self.tabs[i]
                        .active_cmd
                        .as_ref()
                        .map(|command| command.options())
                        .unwrap_or_default(),
                );
                if !self.tabs[i]
                    .active_cmd
                    .as_ref()
                    .is_some_and(|command| command.entity_pick_highlights_hover())
                {
                    self.tabs[i].scene.set_hover_highlight(None);
                }
                self.sync_dyn_fields();
                self.refresh_area_preview(i);
            }
            CmdResult::CommitAndExit(entity) => {
                // For XATTACH: ensure the xref block definition exists before
                // committing the INSERT entity that references it.
                // Extract path early to avoid borrow conflicts.
                let xattach_path: Option<String> = {
                    let tab = &self.tabs[i];
                    if let Some(cmd) = tab.active_cmd.as_ref() {
                        if cmd.name() == "XATTACH" {
                            cmd.xattach_path()
                        } else {
                            None
                        }
                    } else {
                        None
                    }
                };
                if let Some(path) = xattach_path {
                    crate::modules::insert::xattach::prepare_xref_block(
                        &mut self.tabs[i].scene,
                        &path,
                    );
                    // Resolving the xref merged its layer / linetype tables
                    // into the document — mirror them into the Layers panel
                    // and ribbon dropdowns now, not on the next reopen (#407).
                    self.refresh_layer_panel();
                }
                let insert_block_name = match &entity {
                    acadrust::EntityType::Insert(ins) => Some(ins.block_name.clone()),
                    _ => None,
                };
                // Record where this draw ended so ARC_CONT can continue from it
                // (before `entity` is moved into commit_entity).
                self.update_cont_anchor(&entity);
                let label = self.history_label_from_active_cmd(i, "ENTITY");
                let delta_safe = self.delta_add_safe(i, &entity);
                let pending = self.begin_undo(i, label, 1, delta_safe);
                let is_associative_dimension = matches!(
                    entity,
                    acadrust::EntityType::Dimension(
                        acadrust::entities::Dimension::Linear(_)
                            | acadrust::entities::Dimension::Aligned(_)
                    )
                );
                let association_enabled =
                    self.tabs[i].scene.document.header.dimension_associativity == 2;
                let committed = self.commit_entity_handle(entity);
                if is_associative_dimension && association_enabled {
                    if let Some(handle) = committed {
                        let sources = self.infer_dimension_sources_guarded(i, handle);
                        self.tabs[i]
                            .scene
                            .attach_dimension_association(handle, sources);
                    }
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                if let Some(name) = insert_block_name {
                    self.record_block_insert(&name);
                }
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::CommitDimension {
                mut entity,
                association,
                preserve_base_style,
                continue_command,
            } => {
                let label = self.history_label_from_active_cmd(i, "DIMENSION");
                let association_mode = self.tabs[i]
                    .scene
                    .document
                    .header
                    .dimension_associativity;
                let single_source_dimension = matches!(
                    &entity,
                    acadrust::EntityType::Dimension(
                        acadrust::entities::Dimension::Ordinate(_)
                    )
                );
                // A dimension placed on the sheet but measuring model geometry
                // through a viewport carries the compensation as a negative
                // DIMLFAC override.
                self.apply_viewport_dimension_measurement(i, &mut entity);
                // ...and is deliberately *not* associated in paper space: its
                // definition points are projected paper coordinates, so a
                // paper-space association would bind it to geometry that is
                // not there. PR3 records the real dimension -> viewport ->
                // entity chain instead. One gate, shared with
                // `infer_dimension_sources_guarded`.
                let association_allowed = self.dimension_association_allowed(i);
                let inherited_dimension = if preserve_base_style {
                    match &entity {
                        acadrust::EntityType::Dimension(dimension) => Some((
                            dimension.base().common.layer.clone(),
                            dimension.base().style_name.clone(),
                        )),
                        _ => None,
                    }
                } else {
                    None
                };
                let pending = if association_mode == 0 {
                    let layer = self.tabs[i].active_layer.clone();
                    if layer != "0" || entity.as_entity().layer().is_empty() {
                        entity.as_entity_mut().set_layer(layer);
                    }
                    crate::scene::view::dispatch::apply_color(
                        &mut entity,
                        self.ribbon.active_color,
                    );
                    crate::scene::view::dispatch::apply_common_prop(
                        &mut entity,
                        "linetype",
                        &self.ribbon.active_linetype.clone(),
                    );
                    crate::scene::view::dispatch::apply_line_weight(
                        &mut entity,
                        self.ribbon.active_lineweight,
                    );
                    let celtscale = self.tabs[i]
                        .scene
                        .document
                        .header
                        .current_entity_linetype_scale;
                    if (celtscale - 1.0).abs() > 1e-9 && celtscale.abs() > 1e-9 {
                        entity.common_mut().linetype_scale = celtscale;
                    }
                    crate::scene::creation_style::apply_current_creation_styles(
                        &self.tabs[i].scene.document,
                        &mut entity,
                    );
                    if let (Some((layer, style_name)), acadrust::EntityType::Dimension(dimension)) =
                        (inherited_dimension, &mut entity)
                    {
                        dimension.base_mut().common.layer = layer;
                        dimension.base_mut().style_name = style_name;
                    }
                    let pieces = crate::modules::draw::modify::explode::explode_entity(
                        &entity,
                        &self.tabs[i].scene.document,
                    );
                    let delta_safe = pieces
                        .iter()
                        .all(|piece| self.delta_add_safe(i, piece));
                    let pending = self.begin_undo(i, label, pieces.len(), delta_safe);
                    for piece in pieces {
                        self.tabs[i].scene.add_entity(piece);
                    }
                    pending
                } else {
                    let delta_safe = self.delta_add_safe(i, &entity);
                    let pending = self.begin_undo(i, label, 1, delta_safe);
                    if let Some(handle) = self.commit_entity_handle_with_dimension_policy(
                        entity,
                        preserve_base_style,
                    ) {
                        if association_mode == 2 && association_allowed {
                            let mut changes = vec![
                                (handle, crate::scene::ChangeKind::Modified),
                            ];
                            match association {
                                crate::command::DimensionAssociationInput::Infer(source) => {
                                    let sources: Vec<_> = source.map_or_else(
                                        || {
                                            self.infer_dimension_sources_guarded(i, handle)
                                        },
                                        |source| {
                                            if single_source_dimension {
                                                vec![Some(source)]
                                            } else {
                                                vec![Some(source), Some(source)]
                                            }
                                        },
                                    );
                                    self.tabs[i]
                                        .scene
                                        .attach_dimension_association(handle, sources.clone());
                                    changes.extend(sources.into_iter().flatten().map(|source| {
                                        (source, crate::scene::ChangeKind::Modified)
                                    }));
                                }
                                crate::command::DimensionAssociationInput::Explicit(sources) => {
                                    self.tabs[i]
                                        .scene
                                        .attach_dimension_association_sources(handle, sources.clone());
                                    changes.extend(sources.into_iter().flatten().map(|source| {
                                        (source.handle, crate::scene::ChangeKind::Modified)
                                    }));
                                }
                            }
                            changes.sort_by_key(|(handle, _)| handle.value());
                            changes.dedup_by_key(|(handle, _)| handle.value());
                            self.tabs[i].scene.bump_entities(&changes);
                        } else if association_mode == 2 {
                            // Measured through a layout viewport: a paper-space
                            // association would bind projected coordinates to
                            // geometry that is not on the sheet. Record the real
                            // chain instead — dimension -> viewport -> block
                            // path -> entity -> feature — from the AcceptedSnaps
                            // PR1 captured, in definition-point slot order.
                            self.attach_viewport_dimension_association(i, handle);
                        }
                    }
                    pending
                };
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].snap_result = None;
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
                if continue_command {
                    if let Some(prompt) = self.tabs[i]
                        .active_cmd
                        .as_ref()
                        .map(|cmd| cmd.prompt())
                    {
                        self.command_line.push_info(&prompt);
                    }
                } else {
                    self.tabs[i].active_cmd = None;
                    self.restore_pre_cmd_tangent();
                }
            }
            CmdResult::CommitDimensionsAndExit(dimensions) => {
                let association_mode = self.tabs[i]
                    .scene
                    .document
                    .header
                    .dimension_associativity;
                let mut made = 0;
                let pending = if association_mode == 0 {
                    let mut pieces = Vec::new();
                    for (mut entity, _) in dimensions {
                        let layer = self.tabs[i].active_layer.clone();
                        if layer != "0" || entity.as_entity().layer().is_empty() {
                            entity.as_entity_mut().set_layer(layer);
                        }
                        crate::scene::view::dispatch::apply_color(
                            &mut entity,
                            self.ribbon.active_color,
                        );
                        crate::scene::view::dispatch::apply_common_prop(
                            &mut entity,
                            "linetype",
                            &self.ribbon.active_linetype.clone(),
                        );
                        crate::scene::view::dispatch::apply_line_weight(
                            &mut entity,
                            self.ribbon.active_lineweight,
                        );
                        let celtscale = self.tabs[i]
                            .scene
                            .document
                            .header
                            .current_entity_linetype_scale;
                        if (celtscale - 1.0).abs() > 1e-9 && celtscale.abs() > 1e-9 {
                            entity.common_mut().linetype_scale = celtscale;
                        }
                        crate::scene::creation_style::apply_current_creation_styles(
                            &self.tabs[i].scene.document,
                            &mut entity,
                        );
                        let exploded = crate::modules::draw::modify::explode::explode_entity(
                            &entity,
                            &self.tabs[i].scene.document,
                        );
                        if !exploded.is_empty() {
                            made += 1;
                        }
                        pieces.extend(exploded);
                    }
                    let delta_safe = pieces
                        .iter()
                        .all(|piece| self.delta_add_safe(i, piece));
                    let pending = self.begin_undo(i, "QDIM", pieces.len(), delta_safe);
                    for piece in pieces {
                        self.tabs[i].scene.add_entity(piece);
                    }
                    pending
                } else {
                    let delta_safe = dimensions
                        .iter()
                        .all(|(entity, _)| self.delta_add_safe(i, entity));
                    let pending = self.begin_undo(i, "QDIM", dimensions.len(), delta_safe);
                    for (entity, association) in dimensions {
                        let Some(handle) = self.commit_entity_handle(entity) else {
                            continue;
                        };
                        made += 1;
                        if association_mode != 2 {
                            continue;
                        }
                        let sources = match association {
                            crate::command::DimensionAssociationInput::Infer(source) => {
                                source.map_or_else(
                                    || {
                                        self.infer_dimension_sources_guarded(i, handle)
                                            .into_iter()
                                            .map(|source| {
                                                source.map(
                                                    crate::command::DimensionAssociationSource::inferred,
                                                )
                                            })
                                            .collect()
                                    },
                                    |source| {
                                        vec![Some(
                                            crate::command::DimensionAssociationSource::inferred(
                                                source,
                                            ),
                                        )]
                                    },
                                )
                            }
                            crate::command::DimensionAssociationInput::Explicit(sources) => {
                                sources
                            }
                        };
                        self.tabs[i]
                            .scene
                            .attach_dimension_association_sources(handle, sources.clone());
                        let mut changes = vec![(handle, crate::scene::ChangeKind::Modified)];
                        changes.extend(sources.into_iter().flatten().map(|source| {
                            (source.handle, crate::scene::ChangeKind::Modified)
                        }));
                        changes.sort_by_key(|(handle, _)| handle.value());
                        changes.dedup_by_key(|(handle, _)| handle.value());
                        self.tabs[i].scene.bump_entities(&changes);
                    }
                    pending
                };
                if made > 0 {
                    self.tabs[i].dirty = true;
                }
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                self.command_line
                    .push_output(crate::tf!("QDIM  {made} dimensions created.").as_ref());
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::SetQuickDimensionSnapPriority(priority) => {
                self.quick_dimension_snap_priority = priority.min(1);
                self.persist_settings_if_changed();
                let prompt = self.tabs[i].active_cmd.as_ref().map(|command| command.prompt());
                if let Some(prompt) = prompt {
                    self.command_line.push_info(&prompt);
                }
            }
            CmdResult::AlignMLeaders {
                mut handles,
                from,
                to,
            } => {
                handles.retain(|handle| {
                    !self.tabs[i].scene.is_layer_locked(*handle)
                        && matches!(
                            self.tabs[i].scene.document.get_entity(*handle),
                            Some(acadrust::EntityType::MultiLeader(_))
                        )
                });
                if !handles.is_empty() {
                    self.push_undo_snapshot(i, "MLEADERALIGN");
                    if apply_mleader_align(&mut self.tabs[i].scene, &handles, from, to) {
                        self.tabs[i].dirty = true;
                        self.command_line.push_output(
                            crate::t!("MLEADERALIGN  Leaders aligned.").as_ref(),
                        );
                    }
                }
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
            }
            CmdResult::CollectMLeaders { handles, point } => {
                let compatible = compatible_mleader_collect_handles(&self.tabs[i].scene, &handles);
                if compatible.len() >= 2 {
                    self.push_undo_snapshot(i, "MLEADERCOLLECT");
                    if apply_mleader_collect(&mut self.tabs[i].scene, &compatible, point) {
                        self.tabs[i].dirty = true;
                        self.command_line.push_output(
                            crate::t!("MLEADERCOLLECT  Leaders collected.").as_ref(),
                        );
                    }
                }
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
            }
            CmdResult::CommitSolid {
                entity,
                solid,
                history,
                erase_source,
            } => {
                let label = self.history_label_from_active_cmd(i, "SOLID");
                let erase_source = erase_source.filter(|handle| {
                    self.delete_objects != 0
                        && !self.tabs[i].scene.is_layer_locked(*handle)
                });
                let pending = self.begin_undo(
                    i,
                    label,
                    1 + usize::from(erase_source.is_some()),
                    true,
                );
                let handle = self.add_solid_model(entity, *solid, history);
                if !handle.is_null() {
                    if let Some(source) = erase_source {
                        self.tabs[i].scene.erase_entities(&[source]);
                    }
                    self.tabs[i].dirty = true;
                    if let Some(pd) = pending {
                        self.commit_undo_delta(i, pd);
                    }
                }
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
            }
            CmdResult::CommitAndEditText(entity) => {
                let annotative_mleader = matches!(
                    &entity,
                    acadrust::EntityType::MultiLeader(ml) if ml.enable_annotation_scale
                );
                let label = self.history_label_from_active_cmd(i, "ENTITY");
                let delta_safe = self.delta_add_safe(i, &entity) && !annotative_mleader;
                let pending = self.begin_undo(i, label, 1, delta_safe);
                let handle = self.commit_entity_handle(entity);

                if annotative_mleader {
                    let scale_handle = self.tabs[i].scene.creation_annotation_scale_handle();
                    if let (Some(handle), Some(scale_handle)) = (handle, scale_handle) {
                        crate::scene::annotative::create_annotation_context(
                            &mut self.tabs[i].scene.document,
                            handle,
                            scale_handle,
                        );
                        self.tabs[i]
                            .scene
                            .bump_entities(&[(handle, crate::scene::ChangeKind::Modified)]);
                    }
                }

                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                self.ribbon.deactivate_tool();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
                if let Some(h) = handle {
                    return self.begin_text_edit(h);
                }
            }
            CmdResult::CommitManyAndEditText {
                entities,
                edit_index,
                open_editor,
            } => {
                let label = self.history_label_from_active_cmd(i, "ENTITY");
                let delta_safe = entities
                    .iter()
                    .all(|entity| self.delta_add_safe(i, entity));
                let pending = self.begin_undo(i, label, entities.len(), delta_safe);
                let mut edit_handle = None;
                let mut leader_handle = None;
                for (idx, entity) in entities.into_iter().enumerate() {
                    let is_leader = matches!(entity, acadrust::EntityType::Leader(_));
                    let h = self.commit_entity_handle(entity);
                    if idx == edit_index {
                        edit_handle = h;
                    }
                    if is_leader {
                        leader_handle = h;
                    }
                }
                // Link the leader to its annotation so the pair edits as a unit
                // (double-click on the leader resolves to the text entity).
                if let (Some(lh), Some(ah)) = (leader_handle, edit_handle) {
                    let linked = if let Some(acadrust::EntityType::Leader(l)) =
                        self.tabs[i].scene.document.get_entity_mut(lh)
                    {
                        l.annotation_handle = ah;
                        true
                    } else {
                        false
                    };

                    if linked {
                        // The LEADER may already have received its annotation context while
                        // annotation_handle was still NULL. Refresh it now that the MTEXT link
                        // is known so the context represents the finished leader.
                        self.tabs[i]
                            .scene
                            .sync_displayed_annotation_context(lh);

                        self.tabs[i].scene.bump_entities(&[(
                            lh,
                            crate::scene::ChangeKind::Modified,
                        )]);
                    }
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                self.ribbon.deactivate_tool();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
                if open_editor {
                    if let Some(h) = edit_handle {
                        return self.begin_text_edit(h);
                    }
                }
            }
            CmdResult::CreateBlock {
                mut handles,
                name,
                base,
            } => {
                handles.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                if handles.is_empty() {
                    self.command_line
                        .push_info(crate::t!("No editable objects selected.").as_ref());
                    return Task::none();
                }
                self.push_undo_snapshot(i, "BLOCK");
                let ucs = self.tabs[i].ucs_xform();
                let world_to_block = ucs.to_ucs_transform_at(base);
                let block_to_world = ucs.to_wcs_transform_at(base);
                match self.tabs[i]
                    .scene
                    .create_block_from_entities(
                        &handles,
                        &name,
                        &world_to_block,
                        &block_to_world,
                    )
                {
                    Ok(insert_handle) => {
                        self.tabs[i].dirty = true;
                        self.tabs[i].scene.deselect_all();
                        if !insert_handle.is_null() {
                            self.tabs[i].scene.select_entity(insert_handle, false);
                        }
                        self.tabs[i].scene.clear_preview_wire();
                        self.tabs[i].active_cmd = None;
                        self.tabs[i].snap_result = None;
                        self.command_line
                            .push_output(crate::tf!("Block \"{name}\" created.").as_ref());
                        self.refresh_properties();
                    }
                    Err(err) => {
                        self.discard_last_undo_entry(i);
                        self.command_line.push_error(&err);
                        let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                        if let Some(p) = prompt {
                            self.command_line.push_info(&p);
                        }
                    }
                }
            }
            CmdResult::CommitHatch(hatch) => {
                let label = self.history_label_from_active_cmd(i, "HATCH");
                let pending = self.begin_undo(i, label, 1, true);
                let layer = self.tabs[i].active_layer.clone();
                let new_handle = self.tabs[i].scene.add_hatch(hatch, Some(&layer), None);
                if !new_handle.is_null() {
                    self.tabs[i].scene.select_entity(new_handle, true);
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::CommitStyledHatch {
                hatch,
                color,
                transparency,
            } => {
                let label = self.history_label_from_active_cmd(i, "HATCH");
                let pending = self.begin_undo(i, label, 1, true);
                let layer = self.tabs[i].active_layer.clone();
                let new_handle = self.tabs[i].scene.add_hatch(
                    hatch,
                    Some(&layer),
                    Some((color, transparency)),
                );
                if !new_handle.is_null() {
                    self.tabs[i].scene.select_entity(new_handle, true);
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::CommitHatchWithBoundaries {
                mut hatch,
                boundaries,
                entity_style,
            } => {
                let label = self.history_label_from_active_cmd(i, "HATCH");
                let pending = self.begin_undo(i, label, boundaries.len() + 1, true);
                let mut sources = Vec::with_capacity(boundaries.len());
                for boundary in boundaries {
                    let handles = self
                        .commit_entity_handle(boundary)
                        .into_iter()
                        .collect::<Vec<_>>();
                    sources.push(handles);
                }
                if let Some(paths) = hatch.boundary_paths.as_mut() {
                    for (path, handles) in std::sync::Arc::make_mut(paths).iter_mut().zip(&sources)
                    {
                        path.boundary_handles = handles.clone();
                        path.flags.set_external(!handles.is_empty());
                    }
                }
                hatch.boundary_sources = Some(std::sync::Arc::new(sources));
                let layer = self.tabs[i].active_layer.clone();
                let new_handle =
                    self.tabs[i]
                        .scene
                        .add_hatch(hatch, Some(&layer), entity_style);
                if !new_handle.is_null() {
                    self.tabs[i].scene.select_entity(new_handle, true);
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::CommitHatches {
                hatches,
                entity_style,
            } => {
                let label = self.history_label_from_active_cmd(i, "HATCH");
                let pending = self.begin_undo(i, label, hatches.len(), true);
                let layer = self.tabs[i].active_layer.clone();
                for hatch in hatches {
                    let new_handle = self.tabs[i].scene.add_hatch(
                        hatch,
                        Some(&layer),
                        entity_style.clone(),
                    );
                    if !new_handle.is_null() {
                        self.tabs[i].scene.select_entity(new_handle, true);
                    }
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::BatchCopy(mut handles, transforms) => {
                handles.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                if handles.is_empty() {
                    self.tabs[i].active_cmd = None;
                    return Task::none();
                }
                let label = self.history_label_from_active_cmd(i, "ARRAY");
                let count = transforms.len();
                // Same gate as COPY (dimension-free), sized by the total number
                // of copies the array will add.
                let delta_safe = self.delta_copy_safe(i, &handles);
                let pending = self.begin_undo(i, label.clone(), handles.len() * count, delta_safe);
                for t in &transforms {
                    self.tabs[i].scene.copy_entities(&handles, t);
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
                let noun = if count == 1 { "copy" } else { "copies" };
                self.command_line
                    .push_output(crate::tf!("{label}: {count} {noun} created.").as_ref());
                self.refresh_properties();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::ReplaceMany(replacements, additions) => {
                if let Some((handle, _)) = replacements
                    .iter()
                    .find(|(handle, _)| self.tabs[i].scene.is_layer_locked(*handle))
                {
                    self.reject_locked_edit(i, *handle);
                    self.tabs[i].active_cmd = None;
                    return Task::none();
                }
                let label = self.history_label_from_active_cmd(i, "FILLET");
                let was_catchment = self.tabs[i]
                    .active_cmd
                    .as_ref()
                    .is_some_and(|c| c.name() == "SS_CATCHMENT");
                self.push_undo_snapshot(i, label);
                for (handle, entities) in replacements {
                    self.replace_command_entity(i,handle,entities);
                }
                for entity in additions {
                    self.tabs[i].scene.add_entity(entity);
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                if was_catchment {
                    self.command_line
                        .push_info(crate::t!("Catchment tagged successfully.").as_ref());
                }
                self.refresh_properties();
            }
            CmdResult::ReplaceManyContinue(replacements) => {
                if let Some((handle, _)) = replacements
                    .iter()
                    .find(|(handle, _)| self.tabs[i].scene.is_layer_locked(*handle))
                {
                    self.reject_locked_edit(i, *handle);
                    return Task::none();
                }
                let label = self.history_label_from_active_cmd(i, "TRIM");
                self.push_undo_snapshot(i, label);
                for (handle, entities) in replacements {
                    let new_handles = self.replace_command_entity(i,handle,entities);
                    if let Some(command) = self.tabs[i].active_cmd.as_mut() {
                        command.on_entity_replaced(handle, &new_handles);
                    }
                }
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].snap_result = None;
                if let Some(prompt) = self.tabs[i]
                    .active_cmd
                    .as_ref()
                    .map(|command| command.prompt())
                {
                    self.command_line.push_info(&prompt);
                }
                self.refresh_properties();
            }
            CmdResult::UpdateEntityAndFinish { handle, entity } => {
                if self.reject_locked_edit(i, handle) {
                    self.tabs[i].active_cmd = None;
                    return Task::none();
                }
                let label = self.history_label_from_active_cmd(i, "EDIT");
                self.push_undo_snapshot(i, label);
                let is_dimension = matches!(entity, acadrust::EntityType::Dimension(_));
                if let Some(current) = self.tabs[i].scene.document.get_entity_mut(handle) {
                    *current = entity;
                    if is_dimension {
                        self.tabs[i].scene.invalidate_dim_block_recorded(handle);
                    }
                    self.tabs[i]
                        .scene
                        .bump_entities(&[(handle, crate::scene::ChangeKind::Modified)]);
                    self.tabs[i].dirty = true;
                } else {
                    self.command_line.push_error(
                        crate::t!("The selected object is no longer available.").as_ref(),
                    );
                }
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.refresh_properties();
            }
            CmdResult::AddSketchConstraint { kind, refs, driving_param, label } => {
                if let Err(message) = self.tabs[i]
                    .scene
                    .validate_sketch_constraint(kind, &refs, driving_param.as_ref())
                {
                    self.tabs[i].active_cmd = None;
                    self.tabs[i].snap_result = None;
                    self.command_line.push_error(message);
                    return Task::none();
                }
                let scope = self.tabs[i].current_sketch_scope();
                let constraints_before = self
                    .tabs[i]
                    .scene
                    .sketch_constraint_set(scope)
                    .cloned()
                    .unwrap_or_else(|| {
                        crate::scene::sketch_constraints::SketchConstraintSet::new(scope)
                    });
                let touched: Vec<Handle> = refs.iter().map(|r| r.entity).collect();
                let pending = self.begin_undo(i, label, touched.len(), true);
                self.tabs[i]
                    .scene
                    .record_undo_sketch_constraints_before(scope, constraints_before);
                self.tabs[i].scene.sketch_constraint_set_mut(scope).add(kind, refs, driving_param);
                let changes: Vec<(Handle, crate::scene::ChangeKind)> = touched
                    .into_iter()
                    .map(|h| (h, crate::scene::ChangeKind::Modified))
                    .collect();
                self.tabs[i].scene.bump_entities(&changes);
                self.tabs[i].dirty = true;
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.command_line.push_output("Constraint applied.");
                self.refresh_properties();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
            }
            CmdResult::AddCoincidentConstraint { point_a, point_b, label } => {
                let scope = self.tabs[i].current_sketch_scope();
                let to_world = |p: glam::DVec3| acadrust::types::Vector3::new(p.x, p.y, p.z);
                let resolved_a =
                    crate::scene::sketch_constraints::nearest_sketch_point(&self.tabs[i].scene.document, scope, to_world(point_a), None);
                let resolved_b = resolved_a.and_then(|ref_a| {
                    crate::scene::sketch_constraints::nearest_sketch_point(&self.tabs[i].scene.document, scope, to_world(point_b), None)
                        .filter(|ref_b| *ref_b != ref_a)
                });
                match (resolved_a, resolved_b) {
                    (Some(ref_a), Some(ref_b)) => {
                        return self.apply_cmd_result(CmdResult::AddSketchConstraint {
                            kind: crate::scene::sketch_constraints::ConstraintKind::Coincident,
                            refs: vec![ref_a, ref_b],
                            driving_param: None,
                            label,
                        });
                    }
                    _ => {
                        self.command_line.push_error(
                            "Coincident: pick didn't land on a point (endpoint, center, or vertex) — enable an Endpoint/Center object snap and try again.",
                        );
                        self.tabs[i].active_cmd = None;
                        self.tabs[i].snap_result = None;
                    }
                }
            }
            CmdResult::AddPointOnEntityConstraint { point, target, kind, label } => {
                let scope = self.tabs[i].current_sketch_scope();
                let to_world = |p: glam::DVec3| acadrust::types::Vector3::new(p.x, p.y, p.z);
                let resolved = crate::scene::sketch_constraints::nearest_sketch_point(&self.tabs[i].scene.document, scope, to_world(point), Some(target));
                match resolved {
                    Some(point_ref) => {
                        use crate::scene::sketch_constraints::{ConstraintKind, SketchRef};
                        // `CenterPoint` addresses its whole-entity side via
                        // the center marker (same solve as Coincident /
                        // Concentric — `ConstraintKind::CenterPoint`'s own
                        // doc comment); `Midpoint`/`PointOnCurve` address it
                        // as a whole entity.
                        let target_ref =
                            if kind == ConstraintKind::CenterPoint { SketchRef::center(target) } else { SketchRef::whole(target) };
                        return self.apply_cmd_result(CmdResult::AddSketchConstraint {
                            kind,
                            refs: vec![point_ref, target_ref],
                            driving_param: None,
                            label,
                        });
                    }
                    None => {
                        self.command_line.push_error(
                            "Pick didn't land on a point (endpoint, center, or vertex) — enable an Endpoint/Center object snap and try again.",
                        );
                        self.tabs[i].active_cmd = None;
                        self.tabs[i].snap_result = None;
                    }
                }
            }
            CmdResult::AddEqualDistanceConstraint { points, label } => {
                let scope = self.tabs[i].current_sketch_scope();
                let to_world = |p: glam::DVec3| acadrust::types::Vector3::new(p.x, p.y, p.z);
                let mut refs = Vec::with_capacity(4);
                for p in points {
                    let Some(r) = crate::scene::sketch_constraints::nearest_sketch_point(&self.tabs[i].scene.document, scope, to_world(p), None)
                    else {
                        refs.clear();
                        break;
                    };
                    refs.push(r);
                }
                if refs.len() == 4 {
                    return self.apply_cmd_result(CmdResult::AddSketchConstraint {
                        kind: crate::scene::sketch_constraints::ConstraintKind::EqualDistance,
                        refs,
                        driving_param: None,
                        label,
                    });
                }
                self.command_line.push_error(
                    "Equal Distance: a pick didn't land on a point (endpoint, center, or vertex) — enable an Endpoint/Center object snap and try again.",
                );
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
            }
            CmdResult::ReassociateCenterMark { target, source, point } => {
                if self.reject_locked_edit(i, target) {
                    return Task::none();
                }
                self.push_undo_snapshot(i, "CENTERREASSOCIATE");
                if self.tabs[i].scene.reassociate_center_mark(target, source, point) {
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(
                        crate::t!("CENTERREASSOCIATE: center mark associated.").as_ref(),
                    );
                } else {
                    self.command_line.push_error(
                        crate::t!("CENTERREASSOCIATE: the selected source is not circular.").as_ref(),
                    );
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.refresh_properties();
            }
            CmdResult::EditDimensionBreak {
                dimensions,
                operation,
            } => {
                self.push_undo_snapshot(i, "DIMBREAK");
                let result = apply_dimbreak(&mut self.tabs[i].scene, &dimensions, operation);
                if result.changed.is_empty() {
                    self.command_line.push_info(&result.message);
                } else {
                    for handle in &result.changed {
                        self.tabs[i].scene.invalidate_dim_block_recorded(*handle);
                    }
                    let changes = result
                        .changed
                        .iter()
                        .copied()
                        .map(|handle| (handle, crate::scene::ChangeKind::Modified))
                        .collect::<Vec<_>>();
                    self.tabs[i].scene.bump_entities(&changes);
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(&result.message);
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
            }
            CmdResult::EditDimensionJog { dimension, point } => {
                let valid = matches!(
                    self.tabs[i].scene.document.get_entity(dimension),
                    Some(acadrust::EntityType::Dimension(
                        acadrust::entities::Dimension::Linear(_)
                            | acadrust::entities::Dimension::Aligned(_)
                    ))
                );
                if !valid {
                    self.command_line.push_error(
                        crate::t!("DIMJOGLINE: select a linear or aligned dimension.").as_ref(),
                    );
                } else if !self.reject_locked_edit(i, dimension) {
                    self.push_undo_snapshot(i, "DIMJOGLINE");
                    let values = point.map(|point| {
                        use acadrust::xdata::XDataValue;
                        vec![
                            XDataValue::Integer16(387),
                            XDataValue::Integer16(3),
                            XDataValue::Integer16(389),
                            XDataValue::Point3D(acadrust::types::Vector3::new(
                                point.x, point.y, point.z,
                            )),
                        ]
                    });
                    crate::scene::view::dispatch::set_entity_xdata(
                        &mut self.tabs[i].scene.document,
                        dimension,
                        "ACAD_DSTYLE_DIMJAG_POSITION",
                        values,
                    );
                    self.tabs[i].scene.invalidate_dim_block_recorded(dimension);
                    self.tabs[i]
                        .scene
                        .bump_entities(&[(dimension, crate::scene::ChangeKind::Modified)]);
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(
                        if point.is_some() {
                            crate::t!("DIMJOGLINE: jog added.")
                        } else {
                            crate::t!("DIMJOGLINE: jog removed.")
                        }
                        .as_ref(),
                    );
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
            }
            CmdResult::SpaceDimensions {
                base,
                others,
                spacing,
            } => {
                self.push_undo_snapshot(i, "DIMSPACE");
                if apply_dimspace(&mut self.tabs[i].scene, base, &others, spacing) {
                    self.tabs[i].dirty = true;
                    self.command_line
                        .push_output(crate::t!("DIMSPACE  Spacing adjusted.").as_ref());
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
            }
            CmdResult::ReplaceEntity(handle, new_entities) => {
                if self.reject_locked_edit(i, handle) {
                    return Task::none();
                }
                // Detect SPLINEDIT sentinel: a single XLine with a magic layer name.
                if new_entities.len() == 1 {
                    if let acadrust::EntityType::XLine(ref xl) = new_entities[0] {
                        let op = xl.common.layer.clone();
                        if op.starts_with("__SPLINEDIT_") {
                            let label = self.history_label_from_active_cmd(i, "SPLINEDIT");
                            self.push_undo_snapshot(i, label);
                            crate::modules::draw::modify::splinedit::apply_spline_op(
                                &mut self.tabs[i].scene.document,
                                handle,
                                &op,
                            );
                            self.tabs[i].dirty = true;
                            let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                            if let Some(p) = prompt {
                                self.command_line.push_info(&p);
                            }
                            return Task::none();
                        }
                    }
                }
                let label = self.history_label_from_active_cmd(i, "TRIM");
                self.push_undo_snapshot(i, label);
                self.tabs[i].scene.erase_entities(&[handle]);
                let new_handles: Vec<acadrust::Handle> = new_entities
                    .into_iter()
                    .map(|e| self.tabs[i].scene.add_entity(e))
                    .collect();
                // Rebuild replaced dimensions from edited data.
                for &nh in &new_handles {
                    if matches!(
                        self.tabs[i].scene.document.get_entity(nh),
                        Some(acadrust::EntityType::Dimension(_))
                    ) {
                        self.tabs[i].scene.invalidate_dim_block_recorded(nh);
                    }
                }
                let pedit_entities = if self.tabs[i].active_cmd.as_ref().is_some_and(|command| command.name() == "PEDIT") {
                    new_handles.iter().filter_map(|new| self.tabs[i].scene.document.get_entity(*new).cloned()).collect::<Vec<_>>()
                } else { Vec::new() };
                if let Some(cmd) = &mut self.tabs[i].active_cmd {
                    cmd.on_entity_replaced(handle, &new_handles);
                    for entity in pedit_entities { cmd.inject_picked_entity(entity); }
                }
                self.tabs[i].dirty = true;
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
            }
            CmdResult::AttreqNeeded { block_name } => {
                // Collect the full AttributeDefinitions owned by this block
                // record so each created attribute keeps its geometry (#255).
                let attdefs: Vec<acadrust::entities::AttributeDefinition> = {
                    let doc = &self.tabs[i].scene.document;
                    if let Some(br) = doc.block_records.get(&block_name) {
                        br.entity_handles
                            .iter()
                            .filter_map(|&h| {
                                if let Some(acadrust::EntityType::AttributeDefinition(ad)) =
                                    doc.get_entity(h)
                                {
                                    Some(ad.clone())
                                } else {
                                    None
                                }
                            })
                            .collect()
                    } else {
                        vec![]
                    }
                };

                if attdefs.is_empty() {
                    // No attribute definitions — commit the INSERT directly.
                    let entity = self.tabs[i]
                        .active_cmd
                        .as_mut()
                        .and_then(|c| c.attreq_take_insert());
                    if let Some(entity) = entity {
                        let insert_name = match &entity {
                            acadrust::EntityType::Insert(ins) => Some(ins.block_name.clone()),
                            _ => None,
                        };
                        let label = self.history_label_from_active_cmd(i, "INSERT");
                        let delta_safe = self.delta_add_safe(i, &entity);
                        let pending = self.begin_undo(i, label, 1, delta_safe);
                        self.commit_entity(entity);
                        self.tabs[i].dirty = true;
                        self.tabs[i].scene.clear_preview_wire();
                        self.tabs[i].active_cmd = None;
                        self.tabs[i].snap_result = None;
                        if let Some(n) = insert_name {
                            self.record_block_insert(&n);
                        }
                        self.restore_pre_cmd_tangent();
                        if let Some(pd) = pending {
                            self.commit_undo_delta(i, pd);
                        }
                    }
                } else {
                    let completed = self.tabs[i]
                        .active_cmd
                        .as_mut()
                        .and_then(|cmd| cmd.attreq_set_attdefs(attdefs));
                    if let Some(entity) = completed {
                        return self.apply_cmd_result(CmdResult::CommitAndExit(entity));
                    }
                    let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                    if let Some(p) = prompt {
                        self.command_line.push_info(&p);
                    }
                }
            }
            CmdResult::CommitLiveEntity(entity) => {
                let label = self.history_label_from_active_cmd(i, "ENTITY");
                let delta_safe = self.delta_add_safe(i, &entity);
                let pending = self.begin_undo(i, label, 1, delta_safe);
                let handle = self.commit_entity_handle(entity);
                self.tabs[i].dirty = true;
                self.tabs[i].scene.clear_preview_wire();
                if let Some(pd) = pending {
                    self.commit_undo_delta(i, pd);
                }
                if let Some(h) = handle {
                    // Keep the live document Arc unique while later vertices
                    // replace the geometry in place. The final Arc is captured
                    // by UpdateLiveEntity when the command completes.
                    self.defer_live_entity_history_after(i, h);
                    if let Some(cmd) = self.tabs[i].active_cmd.as_mut() {
                        cmd.set_live_handle(h);
                    }
                }
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
            }
            CmdResult::UpdateLiveEntity {
                handle,
                entity,
                finish,
            } => {
                let tracks_draw_anchor = matches!(
                    &entity,
                    acadrust::EntityType::Line(_)
                        | acadrust::EntityType::Arc(_)
                        | acadrust::EntityType::LwPolyline(_)
                        | acadrust::EntityType::Polyline(_)
                        | acadrust::EntityType::Polyline2D(_)
                        | acadrust::EntityType::Polyline3D(_)
                );
                // Replace the live entity's geometry in place, preserving its
                // handle and layer (the fresh entity from the command carries
                // defaults — a NULL handle would desync it from the document
                // map key and drop it from rendering / hit-test). No undo
                // snapshot — the create already pushed one, so the whole object
                // reverts as a unit.
                if let Some(old) = self.tabs[i].scene.document.get_entity_mut(handle) {
                    let old_handle = old.as_entity().handle();
                    let layer = old.as_entity().layer().to_string();
                    let mut new = entity;
                    new.as_entity_mut().set_handle(old_handle);
                    new.as_entity_mut().set_layer(layer);
                    *old = new;
                    self.tabs[i]
                        .scene
                        .bump_entities(&[(handle, crate::scene::ChangeKind::Modified)]);
                    self.tabs[i].dirty = true;
                }
                if tracks_draw_anchor {
                    self.tabs[i].last_draw_anchor = Some(handle);
                }
                if finish {
                    self.finish_live_entity_history(i, handle);
                    self.tabs[i].scene.clear_preview_wire();
                    self.tabs[i].active_cmd = None;
                    self.tabs[i].snap_result = None;
                    self.restore_pre_cmd_tangent();
                } else {
                    let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                    if let Some(p) = prompt {
                        self.command_line.push_info(&p);
                    }
                }
            }
            CmdResult::FinalizeLiveEntity(handle) => {
                // The live geometry already matches the command's committed
                // vertices. Close the deferred history image and UI state
                // without publishing a redundant Modified delta.
                self.finish_live_entity_history(i, handle);
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.restore_pre_cmd_tangent();
            }
            CmdResult::RemoveLiveEntity(handle) => {
                // The command backed off below a valid entity (PLINE Undo at
                // one remaining vertex): take the live entity out of the
                // document, drop its provisional history entry and keep
                // prompting. A later second point creates one fresh entry.
                self.tabs[i].scene.erase_entities(&[handle]);
                if self.tabs[i]
                    .last_draw_anchor
                    .is_some_and(|anchor_handle| anchor_handle == handle)
                {
                    self.tabs[i].last_draw_anchor = None;
                }
                self.discard_last_undo_entry(i);
                self.tabs[i].dirty = true;
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
            }
            cancel @ (CmdResult::Cancel | CmdResult::CancelForSpaceChange) => {
                let space_changed = matches!(cancel, CmdResult::CancelForSpaceChange);
                self.tabs[i].scene.clear_preview_wire();
                if !space_changed && self.tabs[i].suspended_cmd.is_some() {
                    self.tabs[i].active_cmd = self.tabs[i].suspended_cmd.take();
                    let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                    if let Some(p) = prompt {
                        self.command_line.push_info(&p);
                    }
                    let opts = self.tabs[i]
                        .active_cmd
                        .as_ref()
                        .map(|c| c.options())
                        .unwrap_or_default();
                    self.command_line.set_step_options(opts);
                    self.refresh_active_cmd_preview(i);
                } else {
                    self.tabs[i].suspended_cmd = None;
                    self.tabs[i].active_cmd = None;
                    self.tabs[i].snap_result = None;
                    self.restore_pre_cmd_tangent();
                    self.command_line.push_info(crate::t!(if space_changed {
                        "Command cancelled because the active drawing space changed."
                    } else {
                        "Command cancelled."
                    }).as_ref());
                }
            }
            CmdResult::SelectByPath {
                path,
                closed,
                crossing,
            } => {
                // The command picked the path; the hit test lives here, where
                // the camera and the drawing's geometry are. Everything after
                // matches what a lasso does, Remove included.
                let canvas = self.tabs[i].scene.selection.borrow().vp_size;
                let bounds = iced::Rectangle {
                    x: 0.0,
                    y: 0.0,
                    width: canvas.0,
                    height: canvas.1,
                };
                let edit_cam = self.tabs[i]
                    .scene
                    .viewport_edit_frame(canvas)
                    .map(|(cam, _)| cam);
                let (view_rot, eye, all_wires) = self.pick_view(i, &edit_cam, bounds);
                let screen: Vec<iced::Point> = path
                    .iter()
                    .map(|p| {
                        crate::scene::pick::hit_test::world_to_screen(
                            glam::DVec3::new(p[0], p[1], 0.0),
                            view_rot,
                            eye,
                            bounds,
                        )
                    })
                    .collect();
                let handles = self.tabs[i].scene.path_hit_handles(
                    &screen,
                    crossing,
                    !closed,
                    all_wires,
                    view_rot,
                    eye,
                    bounds,
                    |point| self.cursor_model_point(i, &edit_cam, point, bounds),
                );
                if self.select_remove_mode {
                    for h in &handles {
                        self.tabs[i].scene.deselect_entity(*h);
                    }
                } else {
                    for h in &handles {
                        self.tabs[i].scene.select_entity(*h, false);
                    }
                    self.tabs[i].scene.expand_selection_for_groups(&handles);
                }
                self.refresh_properties();
                let selected: Vec<Handle> = self.tabs[i]
                    .scene
                    .selected_entities()
                    .into_iter()
                    .map(|(h, _)| h)
                    .collect();
                let count = handles.len();
                self.command_line
                    .push_info(crate::tf!("{count} object(s) found.").as_ref());
                return self.feed_command(StepInput::SelectionComplete(selected));
            }
            CmdResult::Relaunch(cmd, handles) => {
                self.tabs[i].scene.deselect_all();
                for h in &handles {
                    self.tabs[i].scene.select_entity(*h, false);
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                let _ = self.dispatch_command(&cmd);
            }
            CmdResult::Dispatch(cmd) => {
                // End this interactive front-end, then run the assembled command
                // through the normal dispatcher. Selection is left untouched.
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                let _ = self.dispatch_command(&cmd);
            }
            CmdResult::EditTableCell { handle, point } => {
                // TABLEDIT's pick: end the pick phase and hand (table, point)
                // to the shared cell-edit launcher. A miss or a locked cell
                // re-prompts until a valid table cell is selected.
                use crate::modules::annotate::table_cmd::{table_cell_at, TableCellEditStart};
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();

                if handle == acadrust::Handle::NULL && self.selection_cycling {
                    let mut candidates = Vec::new();
                    for entity in self.tabs[i].scene.document.entities() {
                        if let acadrust::EntityType::Table(table) = entity {
                            let h = table.common.handle;
                            let style = table.table_style_handle.and_then(|style_handle| {
                                self.tabs[i]
                                    .scene
                                    .document
                                    .objects
                                    .get(&style_handle)
                                    .and_then(|object| match object {
                                        acadrust::objects::ObjectType::TableStyle(style) => Some(style),
                                        _ => None,
                                    })
                            });
                            if table_cell_at(table, style, point).is_some() {
                                candidates.push(h);
                            }
                        }
                    }
                    if candidates.len() >= 2 {
                        self.cycle_candidates = Some((self.quick_properties_anchor, candidates));
                        return Task::none();
                    }
                }

                match self.begin_table_cell_edit(i, handle, point) {
                    TableCellEditStart::Started => {}
                    TableCellEditStart::LockedCell => {
                        self.command_line.push_error(
                            crate::t!("The cell is content locked.").as_ref(),
                        );
                        let _ = self.dispatch_command("TABLEDIT");
                    }
                    TableCellEditStart::NoCell => {
                        self.command_line.push_error(
                            crate::t!("No editable table cell picked.").as_ref(),
                        );
                        let _ = self.dispatch_command("TABLEDIT");
                    }
                }
            }
            CmdResult::MatchEntityLayer { dest, src } => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                let src_layer = self.tabs[i]
                    .scene
                    .document
                    .get_entity(src)
                    .map(|e| e.common().layer.clone());
                let dest: Vec<_> = dest
                    .into_iter()
                    .filter(|handle| !self.tabs[i].scene.is_layer_locked(*handle))
                    .collect();
                if dest.is_empty() {
                    self.command_line
                        .push_info(crate::t!("No editable objects selected.").as_ref());
                } else if let Some(layer) = src_layer {
                    self.push_undo_snapshot(i, "LAYMATCH");
                    for h in &dest {
                        if let Some(e) = self.tabs[i].scene.document.get_entity_mut(*h) {
                            e.as_entity_mut().set_layer(layer.clone());
                        }
                    }
                    // New layer changes the baked by-layer colour/linetype/
                    // lineweight — re-tessellate the moved entities so they
                    // repaint immediately (issue #231 class).
                    self.invalidate_property_targets(i, &dest);
                    self.tabs[i].dirty = true;
                    self.command_line
                        .push_info(crate::tf!("Layer matched to \"{layer}\".").as_ref());
                    self.sync_ribbon_layers();
                } else {
                    self.command_line.push_error(crate::t!("Source object not found.").as_ref());
                }
            }
            CmdResult::MatchProperties { mut dest, src } => {
                dest.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                if dest.is_empty() {
                    return Task::none();
                }
                // The command stays active after each apply so more targets
                // can keep being picked; Enter / Esc ends it (#362).
                let src_clone = self.tabs[i].scene.document.get_entity(src).cloned();
                let src_common = src_clone.as_ref().map(|e| e.common().clone());
                let thickness = src_clone
                    .as_ref()
                    .and_then(crate::scene::view::dispatch::entity_thickness);
                // This application record is the hatch background colour.
                // Keep the outer Option to distinguish "source is not a
                // hatch" from "source hatch has no background".
                let hatch_background_xdata: Option<Option<Vec<acadrust::xdata::XDataValue>>> =
                    match src_clone.as_ref() {
                        Some(acadrust::EntityType::Hatch(h)) => Some(
                            h.common
                                .extended_data
                                .get_record("HATCHBACKGROUNDCOLOR")
                                .map(|r| r.values.clone()),
                        ),
                        _ => None,
                    };
                // Dimension-style overrides ride the ACAD record, identified
                // by a leading DSTYLE string. Matching replicates that payload
                // (or clears the destination when the source has none).
                let dstyle_xdata: Option<Vec<(i16, acadrust::xdata::XDataValue)>> = src_clone
                    .as_ref()
                    .filter(|e| {
                        matches!(
                            e,
                            acadrust::EntityType::Dimension(_) | acadrust::EntityType::Leader(_)
                        )
                    })
                    .map(|e| crate::entities::dim_override::pairs(&e.common().extended_data));

                if let Some(common) = src_common {
                    self.apply_property_op(i, "MATCHPROP", &dest, |app, handle| {
                        let mut is_dim = false;
                        let mut is_hatch = false;
                        if let Some(e) = app.tabs[i].scene.document.get_entity_mut(handle) {
                            e.as_entity_mut().set_layer(common.layer.clone());
                            crate::scene::view::dispatch::apply_color(e, common.color);
                            crate::scene::view::dispatch::apply_line_weight(e, common.line_weight);
                            {
                                let dst_common = e.common_mut();
                                dst_common.linetype = common.linetype.clone();
                                dst_common.linetype_handle = common.linetype_handle;
                                dst_common.linetype_scale = common.linetype_scale;
                                dst_common.transparency = common.transparency.clone();
                                dst_common.color_name = common.color_name.clone();
                                dst_common.color_book_handle = common.color_book_handle;
                                dst_common.full_visual_style_handle =
                                    common.full_visual_style_handle;
                                dst_common.face_visual_style_handle =
                                    common.face_visual_style_handle;
                                dst_common.edge_visual_style_handle =
                                    common.edge_visual_style_handle;
                                dst_common.material_flags = common.material_flags;
                                dst_common.material_handle = common.material_handle;
                                dst_common.shadow_flags = common.shadow_flags;
                                dst_common.plotstyle_flags = common.plotstyle_flags;
                                dst_common.plotstyle_handle = common.plotstyle_handle;
                            }
                            if let Some(value) = thickness {
                                crate::scene::view::dispatch::set_entity_thickness(e, value);
                            }
                            if let Some(se) = &src_clone {
                                is_dim = matches!(e, acadrust::EntityType::Dimension(_));
                                is_hatch = matches!(e, acadrust::EntityType::Hatch(_));
                                match_special_props(se, e);
                            }
                        }
                        if is_hatch {
                            if let Some(values) = &hatch_background_xdata {
                                crate::scene::view::dispatch::set_entity_xdata(
                                    &mut app.tabs[i].scene.document,
                                    handle,
                                    "HATCHBACKGROUNDCOLOR",
                                    values.clone(),
                                );
                            }
                        }
                        // Dim-style overrides follow the style for dimension /
                        // leader destinations — through set_entity_xdata so no
                        // stale raw record survives.
                        if dstyle_xdata.is_some()
                            || matches!(
                                app.tabs[i].scene.document.get_entity(handle),
                                Some(
                                    acadrust::EntityType::Dimension(_)
                                        | acadrust::EntityType::Leader(_)
                                )
                            )
                        {
                            if matches!(
                                app.tabs[i].scene.document.get_entity(handle),
                                Some(
                                    acadrust::EntityType::Dimension(_)
                                        | acadrust::EntityType::Leader(_)
                                )
                            ) && matches!(
                                src_clone,
                                Some(
                                    acadrust::EntityType::Dimension(_)
                                        | acadrust::EntityType::Leader(_)
                                )
                            ) {
                                crate::entities::dim_override::replace(
                                    &mut app.tabs[i].scene.document,
                                    handle,
                                    dstyle_xdata.clone().unwrap_or_default(),
                                );
                            }
                        }
                        // A restyled dimension renders from its baked *D block —
                        // drop the stale block so the new style shows (#398).
                        if is_dim {
                            app.tabs[i].scene.invalidate_dim_block_recorded(handle);
                        }
                        // Hatch fills render from a prebuilt model (#415).
                        app.tabs[i].scene.refresh_fill_model(handle);
                    });
                    // Color / linetype / lineweight are baked into the cached
                    // wires at tessellation time; re-tessellate only the matched
                    // objects instead of rebuilding a large drawing.
                    let changes: Vec<_> = dest
                        .iter()
                        .copied()
                        .map(|handle| (handle, crate::scene::ChangeKind::Modified))
                        .collect();
                    self.tabs[i].scene.bump_entities(&changes);
                    self.command_line
                        .push_info(crate::tf!("Properties matched to {} object(s).", dest.len()).as_ref());
                    // Clear the consumed target selection and keep prompting.
                    self.tabs[i].scene.deselect_all();
                    if let Some(cmd) = &self.tabs[i].active_cmd {
                        self.command_line.push_info(&cmd.prompt());
                    }
                } else {
                    self.command_line.push_error(crate::t!("Source object not found.").as_ref());
                    self.tabs[i].active_cmd = None;
                    self.tabs[i].snap_result = None;
                    self.tabs[i].scene.clear_preview_wire();
                }
            }
            CmdResult::PasteClipboard { base_pt } => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                if self.clipboard.is_empty() {
                    self.command_line.push_error(crate::t!("Clipboard is empty.").as_ref());
                } else {
                    let delta = base_pt - self.clipboard_base;
                    let translate = crate::command::EntityTransform::Translate(delta);
                    self.push_undo_snapshot(i, "PASTECLIP");
                    let count = self.clipboard.len();
                    let by_index = self.finalize_paste(i, Some(translate));
                    self.tabs[i].scene.deselect_all();
                    for h in by_index.iter().copied().filter(|h| !h.is_null()) {
                        self.tabs[i].scene.select_entity(h, false);
                    }
                    self.tabs[i].dirty = true;
                    // Surface any layers the paste brought in (cross-drawing)
                    // in the layer manager and the layer dropdown.
                    self.refresh_layer_panel();
                    self.refresh_properties();
                    self.command_line
                        .push_info(crate::tf!("{count} object(s) pasted.").as_ref());
                }
            }
            CmdResult::CreateGroup { mut handles, name } => {
                handles.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                if handles.is_empty() {
                    return Task::none();
                }
                let undo = self.begin_group_undo(i, "GROUP");
                self.tabs[i].scene.create_group(name.clone(), handles);
                self.tabs[i].dirty = true;
                self.commit_group_undo(i, undo);
                self.command_line
                    .push_info(crate::tf!("Group \"{}\" created.", name).as_ref());
            }
            CmdResult::DeleteGroups { mut handles } => {
                handles.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                if handles.is_empty() {
                    return Task::none();
                }
                let undo = self.begin_group_undo(i, "UNGROUP");
                let count = self.tabs[i].scene.delete_groups_containing(&handles);
                self.tabs[i].dirty = true;
                self.commit_group_undo(i, undo);
                if count > 0 {
                    self.command_line
                        .push_info(crate::tf!("{} group(s) dissolved.", count).as_ref());
                } else {
                    self.command_line
                        .push_info(crate::t!("No groups found for selected objects.").as_ref());
                }
            }
            CmdResult::VpLayerUpdate {
                vp_handle,
                freeze,
                thaw,
            } => {
                // Resolve layer names → handles, then update frozen_layers on the viewport(s).
                // vp_handle == Handle::NULL means "apply to all viewports in current layout".
                let freeze_handles: Vec<Handle> = freeze
                    .iter()
                    .filter_map(|name| {
                        self.tabs[i]
                            .scene
                            .document
                            .layers
                            .iter()
                            .find(|l| l.name.eq_ignore_ascii_case(name))
                            .map(|l| l.handle)
                    })
                    .collect();
                let thaw_handles: Vec<Handle> = thaw
                    .iter()
                    .filter_map(|name| {
                        self.tabs[i]
                            .scene
                            .document
                            .layers
                            .iter()
                            .find(|l| l.name.eq_ignore_ascii_case(name))
                            .map(|l| l.handle)
                    })
                    .collect();

                let mut frozen_count = 0usize;
                let mut thawed_count = 0usize;

                // Collect target viewport handles
                let target_handles: Vec<Handle> = if vp_handle == acadrust::Handle::NULL {
                    // All viewports in current layout block
                    let block_handle = self.tabs[i].scene.current_layout_block_handle_pub();
                    self.tabs[i]
                        .scene
                        .document
                        .entities()
                        .filter(|e| {
                            e.common().owner_handle == block_handle
                                && matches!(e, acadrust::EntityType::Viewport(_))
                        })
                        .map(|e| e.common().handle)
                        .collect()
                } else {
                    vec![vp_handle]
                };

                for &target_handle in &target_handles {
                    if let Some(acadrust::EntityType::Viewport(vp)) =
                        self.tabs[i].scene.document.get_entity_mut(target_handle)
                    {
                        for h in &freeze_handles {
                            if !vp.frozen_layers.contains(h) {
                                vp.frozen_layers.push(*h);
                                frozen_count += 1;
                            }
                        }
                        for h in &thaw_handles {
                            let before = vp.frozen_layers.len();
                            vp.frozen_layers.retain(|fh| fh != h);
                            if vp.frozen_layers.len() < before {
                                thawed_count += 1;
                            }
                        }
                    }
                }

                if frozen_count > 0 || thawed_count > 0 {
                    self.push_undo_snapshot(i, "VPLAYER");
                    self.tabs[i].dirty = true;
                    if frozen_count > 0 {
                        self.command_line.push_info(crate::tf!(
                            "VPLAYER: {frozen_count} layer(s) frozen in viewport."
                        ).as_ref());
                    }
                    if thawed_count > 0 {
                        self.command_line.push_info(crate::tf!(
                            "VPLAYER: {thawed_count} layer(s) thawed in viewport."
                        ).as_ref());
                    }
                    // Sync layer panel so VP freeze columns update immediately.
                    let doc_layers = self.tabs[i].scene.document.layers.clone();
                    let vp_info = self.tabs[i].scene.viewport_list();
                    self.tabs[i]
                        .layers
                        .sync_with_viewports(&doc_layers, vp_info);
                }

                // Show updated prompt (command stays active for more operations).
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
            }

            CmdResult::ZoomToWindow { p1, p2 } => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.tabs[i].scene.remember_current_view();
                self.tabs[i]
                    .scene
                    .zoom_to_window(p1.as_vec3(), p2.as_vec3());
                self.command_line.push_output(crate::t!("Zoom Window").as_ref());
            }
            CmdResult::Measurement(msg) => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.command_line.push_output(&msg);
            }
            CmdResult::ReportMeasurement(msg) => {
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.refresh_area_preview(i);
                self.command_line.push_output(&msg);
                if let Some(prompt) = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt()) {
                    self.command_line.push_info(&prompt);
                }
            }
            CmdResult::ReportError(msg) => {
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.command_line.push_error(&msg);
                if let Some(prompt) = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt()) {
                    self.command_line.push_info(&prompt);
                }
            }
            CmdResult::ReportMeasurementAndDeselect(msg) => {
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.deselect_all();
                self.tabs[i].scene.clear_preview_wire();
                self.refresh_area_preview(i);
                self.refresh_properties();
                self.command_line.push_output(&msg);
                if let Some(prompt) = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt()) {
                    self.command_line.push_info(&prompt);
                }
            }
            CmdResult::DeselectAndContinue => {
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.deselect_all();
                self.tabs[i].scene.clear_preview_wire();
                self.refresh_area_preview(i);
                self.refresh_properties();
                if let Some(prompt) = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt()) {
                    self.command_line.push_info(&prompt);
                }
            }
            CmdResult::AlignSelected {
                mut handles,
                src1,
                dst1,
                angle_rad,
                scale,
            } => {
                handles.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                if handles.is_empty() {
                    self.tabs[i].active_cmd = None;
                    self.tabs[i].snap_result = None;
                    self.tabs[i].scene.clear_preview_wire();
                    self.restore_pre_cmd_tangent();
                } else {
                    let label = self.history_label_from_active_cmd(i, "ALIGN");
                    // A chain of transform_entities on the same handles — the
                    // recording keeps each entity's first (pre-align) image, so
                    // it's delta-safe like a single transform.
                    let pending = self.begin_undo(i, label, handles.len(), true);
                    // Step 1: translate so src1 is at origin
                    self.tabs[i].scene.transform_entities(
                        &handles,
                        &crate::command::EntityTransform::Translate(-src1),
                    );
                    // Step 2: uniform scale (only when != 1)
                    if (scale - 1.0).abs() > 1e-4 {
                        self.tabs[i].scene.transform_entities(
                            &handles,
                            &crate::command::EntityTransform::Scale {
                                center: glam::DVec3::ZERO,
                                factor: scale,
                            },
                        );
                    }
                    // Step 3: rotate in the XY plane by angle_rad
                    if angle_rad.abs() > 1e-4 {
                        self.tabs[i].scene.transform_entities(
                            &handles,
                            &crate::command::EntityTransform::Rotate {
                                center: glam::DVec3::ZERO,
                                axis: glam::DVec3::Z,
                                angle_rad,
                            },
                        );
                    }
                    // Step 4: translate to dst1
                    self.tabs[i].scene.transform_entities(
                        &handles,
                        &crate::command::EntityTransform::Translate(dst1),
                    );
                    self.tabs[i].dirty = true;
                    self.tabs[i].scene.deselect_all();
                    for h in &handles {
                        self.tabs[i].scene.select_entity(*h, false);
                    }
                    self.tabs[i].scene.clear_preview_wire();
                    self.tabs[i].active_cmd = None;
                    self.tabs[i].snap_result = None;
                    self.restore_pre_cmd_tangent();
                    self.command_line.push_output(crate::t!("ALIGN: applied.").as_ref());
                    self.refresh_properties();
                    if let Some(pd) = pending {
                        self.commit_undo_delta(i, pd);
                    }
                }
            }
            CmdResult::LengthenEntity {
                handle,
                pick_pt,
                mode,
            } => {
                if self.reject_locked_edit(i, handle) {
                    return Task::none();
                }
                use crate::modules::draw::modify::lengthen::lengthen_entity;
                let result = self.tabs[i]
                    .scene
                    .document
                    .get_entity(handle)
                    .and_then(|e| lengthen_entity(e, pick_pt.as_vec3(), &mode));
                match result {
                    Some(new_entity) => {
                        let label = self.history_label_from_active_cmd(i, "LENGTHEN");
                        self.push_undo_snapshot(i, label);
                        self.tabs[i].scene.erase_entities(&[handle]);
                        self.tabs[i].scene.add_entity(new_entity);
                        self.tabs[i].dirty = true;
                        self.command_line.push_output(crate::t!("LENGTHEN: applied.").as_ref());
                        self.refresh_properties();
                    }
                    None => {
                        self.command_line
                            .push_error(crate::t!("LENGTHEN: entity type not supported.").as_ref());
                    }
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
            }
            CmdResult::DivideEntity { handle, n, marker } => {
                use crate::modules::draw::inquiry::divide::divide_entity;
                let pts = self.tabs[i]
                    .scene
                    .document
                    .get_entity(handle)
                    .map(|e| divide_entity(e, n, marker.as_ref()))
                    .unwrap_or_default();
                let count = pts.len();
                if count > 0 {
                    self.push_undo_snapshot(i, "DIVIDE");
                    let layer = self.tabs[i].active_layer.clone();
                    for mut p in pts {
                        p.as_entity_mut().set_layer(layer.clone());
                        self.tabs[i].scene.add_entity(p);
                    }
                    self.tabs[i].dirty = true;
                    self.command_line
                        .push_output(crate::tf!("DIVIDE: {count} marker(s) placed.").as_ref());
                } else {
                    self.command_line
                        .push_error(crate::t!("DIVIDE: entity type not supported or N < 2.").as_ref());
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
            }
            CmdResult::MeasureEntity {
                handle,
                segment_length,
                pick_point,
                marker,
            } => {
                use crate::modules::draw::inquiry::divide::measure_entity;
                let pts = self.tabs[i]
                    .scene
                    .document
                    .get_entity(handle)
                    .map(|e| measure_entity(e, segment_length, pick_point, marker.as_ref()))
                    .unwrap_or_default();
                let count = pts.len();
                if count > 0 {
                    self.push_undo_snapshot(i, "MEASURE");
                    let layer = self.tabs[i].active_layer.clone();
                    for mut p in pts {
                        p.as_entity_mut().set_layer(layer.clone());
                        self.tabs[i].scene.add_entity(p);
                    }
                    self.tabs[i].dirty = true;
                    self.command_line
                        .push_output(crate::tf!("MEASURE: {count} marker(s) placed.").as_ref());
                } else {
                    self.command_line
                        .push_output(crate::t!("MEASURE: 0 markers placed.").as_ref());
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
            }
            CmdResult::PeditOp { handle, op } => return self.apply_pedit_result(i, handle, op),
            CmdResult::JoinToSource { source, handles } => {
                if self.reject_locked_edit(i, source) { return Task::none(); }
                let joined = self.tabs[i].scene.document.get_entity(source).and_then(|entity| {
                    let candidates: Vec<_> = handles.iter().filter(|handle| **handle != source && !self.tabs[i].scene.is_layer_locked(**handle))
                        .filter_map(|handle| self.tabs[i].scene.document.get_entity(*handle).map(|entity| (*handle,entity))).collect();
                    crate::modules::draw::modify::join::join_to_source(entity,&candidates)
                });
                if let Some((replacement, consumed)) = joined {
                    self.push_undo_snapshot(i,"JOIN");
                    if let Some(entity) = self.tabs[i].scene.document.get_entity_mut(source) { *entity = replacement; }
                    self.tabs[i].scene.erase_entities(&consumed);
                    self.tabs[i].scene.refresh_fill_model(source);
                    self.tabs[i].scene.bump_entities(&[(source,crate::scene::ChangeKind::Modified)]);
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(&format!("JOIN: {} objects joined to source.",consumed.len()));
                    self.refresh_properties();
                } else { self.command_line.push_info("JOIN: no compatible objects joined to source."); }
                self.tabs[i].active_cmd = None; self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire(); self.restore_pre_cmd_tangent();
            }
            CmdResult::JoinEntities(handles) => {
                if let Some(handle) = handles
                    .iter()
                    .find(|handle| self.tabs[i].scene.is_layer_locked(**handle))
                {
                    self.reject_locked_edit(i, *handle);
                    return Task::none();
                }
                use crate::modules::draw::modify::join::join_entities;
                let pairs: Vec<_> = handles
                    .iter()
                    .filter_map(|&h| self.tabs[i].scene.document.get_entity(h).map(|e| (h, e)))
                    .collect();
                match join_entities(&pairs) {
                    Some((to_remove, merged)) => {
                        let label = self.history_label_from_active_cmd(i, "JOIN");
                        self.push_undo_snapshot(i, label);
                        self.tabs[i].scene.erase_entities(&to_remove);
                        let count_in = to_remove.len();
                        let count_out = merged.len();
                        for e in merged {
                            self.tabs[i].scene.add_entity(e);
                        }
                        self.tabs[i].dirty = true;
                        self.tabs[i].scene.clear_preview_wire();
                        self.tabs[i].active_cmd = None;
                        self.tabs[i].snap_result = None;
                        self.restore_pre_cmd_tangent();
                        self.command_line.push_output(crate::tf!(
                            "JOIN: {count_in} object(s) joined into {count_out}."
                        ).as_ref());
                        self.refresh_properties();
                    }
                    None => {
                        self.tabs[i].active_cmd = None;
                        self.tabs[i].snap_result = None;
                        self.tabs[i].scene.clear_preview_wire();
                        self.restore_pre_cmd_tangent();
                        self.command_line.push_error(
                            crate::t!("JOIN: objects don't form a single connected chain, or contain an unsupported type / tilted arc.").as_ref(),
                        );
                    }
                }
            }
            CmdResult::BreakEntity { handle, p1, p2 } => {
                if self.reject_locked_edit(i, handle) {
                    return Task::none();
                }
                use crate::modules::draw::modify::break_cmd::break_entity;
                let replacement = self.tabs[i]
                    .scene
                    .document
                    .get_entity(handle)
                    .and_then(|e| break_entity(e, p1, p2));
                match replacement {
                    Some(frags) => {
                        let unchanged = frags.len() == 1 && self.tabs[i].scene.document.get_entity(handle)
                            .is_some_and(|original| {
                                let mut fragment = frags[0].clone();
                                fragment.common_mut().handle = handle;
                                &fragment == original
                            });
                        if unchanged {
                            self.tabs[i].active_cmd = None;
                            self.tabs[i].snap_result = None;
                            self.tabs[i].scene.clear_preview_wire();
                            self.restore_pre_cmd_tangent();
                            self.command_line.push_output("BREAK: no geometry changed.");
                            return Task::none();
                        }
                        let label = self.history_label_from_active_cmd(i, "BREAK");
                        self.push_undo_snapshot(i, label);
                        let count = frags.len();
                        let owner = self.tabs[i].scene.document.get_entity(handle)
                            .map(|entity| entity.common().owner_handle);
                        let mut fragments = frags.into_iter();
                        if let Some(mut first) = fragments.next() {
                            first.common_mut().handle = handle;
                            self.tabs[i].scene.update_entity(first);
                            for mut fragment in fragments {
                                fragment.common_mut().handle = Handle::NULL;
                                if let Some(owner) = owner { fragment.common_mut().owner_handle = owner; }
                                self.tabs[i].scene.add_entity(fragment);
                            }
                        } else {
                            self.tabs[i].scene.erase_entities(&[handle]);
                        }
                        self.tabs[i].dirty = true;
                        self.tabs[i].scene.clear_preview_wire();
                        self.tabs[i].active_cmd = None;
                        self.tabs[i].snap_result = None;
                        self.restore_pre_cmd_tangent();
                        self.command_line
                            .push_output(crate::tf!("BREAK: {} fragment(s).", count).as_ref());
                        self.refresh_properties();
                    }
                    None => {
                        self.tabs[i].active_cmd = None;
                        self.tabs[i].snap_result = None;
                        self.tabs[i].scene.clear_preview_wire();
                        self.restore_pre_cmd_tangent();
                        self.command_line
                            .push_error(crate::t!("BREAK: entity type not supported.").as_ref());
                    }
                }
            }
            CmdResult::SetPlotWindow { p1, p2 } => {
                let layout_name = self.tabs[i].scene.current_layout.clone();
                if layout_name == "Model" {
                    // Model space: remember the window (world X/Y) for the plot dialog.
                    let x0 = p1.x.min(p2.x);
                    let y0 = p1.y.min(p2.y);
                    let x1 = p1.x.max(p2.x);
                    let y1 = p1.y.max(p2.y);
                    self.plot_window = Some((x0, y0, x1, y1));
                    self.command_line
                        .push_output(crate::tf!("Plot window: {x0:.2},{y0:.2} to {x1:.2},{y1:.2}").as_ref());
                    // Pick window closed the plot dialog so the viewport could
                    // receive the two clicks — bring the dialog back with the
                    // window now active.
                    self.plot_dialog.area = "Window".to_string();
                    self.active_modal = Some(super::ModalKind::Plot);
                } else {
                    // PLOTWINDOW always describes the plotted layout. In MSPACE
                    // the command points are model coordinates, so map them back
                    // through the active floating viewport first.
                    let p1 = self.tabs[i].scene.model_to_paper(p1);
                    let p2 = self.tabs[i].scene.model_to_paper(p2);
                    let x1 = p1.x.min(p2.x);
                    let y1 = p1.y.min(p2.y);
                    let x2 = p1.x.max(p2.x);
                    let y2 = p1.y.max(p2.y);
                    self.plot_window = Some((x1, y1, x2, y2));
                    self.command_line.push_output(crate::tf!(
                        "Plot window: {x1:.2},{y1:.2} to {x2:.2},{y2:.2}"
                    ).as_ref());
                    self.plot_dialog.area = "Window".to_string();
                    self.active_modal = Some(super::ModalKind::Plot);
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
            }
            CmdResult::QuickPrint(handles) => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                return self.on_quick_print_handles(handles);
            }
            CmdResult::StretchWindow {
                mut handles,
                windows,
            } => {
                // Accumulate every entity touched by any crossing window. Keep STRETCH
                // in its selection stage; Enter is what advances to the base point.
                {
                    let scene = &self.tabs[i].scene;

                    for (win_min, win_max) in &windows {
                        handles.extend(
                            scene
                                .interaction_handles_in_world_aabb([
                                    win_min.x,
                                    win_min.y,
                                    win_max.x,
                                    win_max.y,
                                ])
                                .into_iter()
                                .filter(|&handle| !scene.is_layer_locked(handle)),
                        );
                    }
                }

                handles.sort_unstable_by_key(|handle| handle.value());
                handles.dedup();

                if handles.is_empty() {
                    self.command_line.push_output(
                        crate::t!("STRETCH: nothing crosses the window.").as_ref(),
                    );
                } else {
                    // Visual feedback must only highlight entities that actually have a
                    // stretchable point inside one of the crossing windows. `handles` can
                    // contain the whole candidate/preselection set, while `windows` decides
                    // which vertices will really move.
                    let point_inside = |point: glam::DVec3| {
                        const EPS: f64 = 1.0e-9;

                        windows.iter().any(|(win_min, win_max)| {
                            point.x >= win_min.x - EPS
                                && point.x <= win_max.x + EPS
                                && point.y >= win_min.y - EPS
                                && point.y <= win_max.y + EPS
                                && point.z >= win_min.z - EPS
                                && point.z <= win_max.z + EPS
                        })
                    };

                    let mut visual_handles = Vec::new();

                    for &handle in &handles {
                        let wires = self.tabs[i].scene.wire_models_for(&[handle]);

                        let affected = wires.iter().any(|wire| {
                            // LINE / LWPOLYLINE / other vertex-based entities.
                            let vertex_hit = wire
                                .key_vertices
                                .iter()
                                .any(|point| point_inside(glam::DVec3::from_array(*point)));

                            if vertex_hit {
                                return true;
                            }

                            // Whole-object STRETCH cases such as circles/arcs/inserts/points:
                            // use only their meaningful anchor snap, not quadrants or
                            // tessellated display points.
                            wire.snap_pts.iter().any(|(point, hint)| {
                                matches!(
                                    hint,
                                    crate::scene::model::wire_model::SnapHint::Center
                                        | crate::scene::model::wire_model::SnapHint::Insertion
                                        | crate::scene::model::wire_model::SnapHint::Node
                                ) && point_inside(*point)
                            })
                        });

                        if affected {
                            visual_handles.push(handle);
                        }
                    }

                    self.tabs[i].scene.deselect_all();
                    self.tabs[i].scene.select_entities(&visual_handles);
                    self.refresh_selected_grips();
                    // STRETCH temporary grips: keep only the actual vertices/endpoints
                    // that lie inside one of the accumulated crossing windows.
                    //
                    // Mid-segment grips are deliberately excluded: STRETCH moves vertices,
                    // not the midpoint affordances used by normal grip editing.
                    let mut stretch_grips = Vec::new();
                    let mut stretch_grip_handles = Vec::new();

                    for (handle, grip) in std::mem::take(&mut self.tabs[i].selected_grip_handles)
                        .into_iter()
                        .zip(std::mem::take(&mut self.tabs[i].selected_grips))
                    {
                        if !grip.is_midpoint && point_inside(grip.world) {
                            stretch_grip_handles.push(handle);
                            stretch_grips.push(grip);
                        }
                    }

                    self.tabs[i].selected_grip_handles = stretch_grip_handles;
                    self.tabs[i].selected_grips = stretch_grips;
                }

                use crate::command::CadCommand;
                use crate::modules::draw::modify::stretch::StretchCommand;

                let wires = self.tabs[i].scene.wire_models_for(&handles);

                let cmd = StretchCommand::with_windows(
                    handles,
                    wires,
                    windows,
                );

                self.command_line.push_info(&CadCommand::prompt(&cmd));
                self.tabs[i].active_cmd = Some(Box::new(cmd));
            }
            CmdResult::StretchEntities {
                mut handles,
                windows,
                delta,
            } => {
                handles.retain(|handle| !self.tabs[i].scene.is_layer_locked(*handle));
                if handles.is_empty() {
                    self.tabs[i].active_cmd = None;
                    return Task::none();
                }
                let structural = handles.iter().any(|handle| {
                    matches!(
                        self.tabs[i].scene.document.get_entity(*handle),
                        Some(acadrust::EntityType::Dimension(_))
                    )
                });
                let pending = self.begin_undo(i, "STRETCH", handles.len(), !structural);
                let mut count = 0usize;
                let mut changed_handles = Vec::new();

                // Helper: is DXF point (x, y) inside the world-space window?
                // Drawing plane is world XY (= DXF XY).
                let in_win = |x: f64, y: f64| -> bool {
                    windows.iter().any(|(win_min, win_max)| {
                        x >= win_min.x
                            && x <= win_max.x
                            && y >= win_min.y
                            && y <= win_max.y
                    })
                };

                let dx = delta.x as f64;
                let dy = delta.y as f64; // drawing plane is world XY
                let dz = delta.z as f64;

                // Dimensions whose points moved — their baked *D block is
                // stale afterwards and must be dropped (see #398 / #372).
                let mut stretched_dims: Vec<acadrust::Handle> = Vec::new();
                for handle in &handles {
                    let before = self.tabs[i].scene.document.get_entity_arc(*handle);
                    let Some(entity) = self.tabs[i].scene.document.get_entity_mut(*handle) else {
                        continue;
                    };
                    let mut stretched = false;
                    match entity {
                        acadrust::EntityType::Line(l) => {
                            let s_in = in_win(l.start.x, l.start.y);
                            let e_in = in_win(l.end.x, l.end.y);
                            if s_in {
                                l.start.x += dx;
                                l.start.y += dy;
                                l.start.z += dz;
                                stretched = true;
                            }
                            if e_in {
                                l.end.x += dx;
                                l.end.y += dy;
                                l.end.z += dz;
                                stretched = true;
                            }
                        }
                        acadrust::EntityType::LwPolyline(p) => {
                            let Some(mut world) =
                                crate::entities::curve::lwpolyline_world_xy(p)
                            else {
                                continue;
                            };
                            for v in &mut world.vertices {
                                if in_win(v.location.x, v.location.y) {
                                    v.location.x += dx;
                                    v.location.y += dy;
                                    stretched = true;
                                }
                            }
                            if stretched {
                                *p = world;
                            }
                        }
                        acadrust::EntityType::Polyline2D(p) => {
                            for v in &mut p.vertices {
                                if in_win(v.location.x, v.location.y) {
                                    v.location.x += dx;
                                    v.location.y += dy;
                                    stretched = true;
                                }
                            }
                        }
                        acadrust::EntityType::Polyline(p) => {
                            for v in &mut p.vertices {
                                if in_win(v.location.x, v.location.z) {
                                    v.location.x += dx;
                                    v.location.z += dy;
                                    stretched = true;
                                }
                            }
                        }
                        acadrust::EntityType::Arc(a) => {
                            if in_win(a.center.x, a.center.y) {
                                a.center.x += dx;
                                a.center.y += dy;
                                a.center.z += dz;
                                stretched = true;
                            }
                        }
                        acadrust::EntityType::Circle(c) => {
                            if in_win(c.center.x, c.center.y) {
                                c.center.x += dx;
                                c.center.y += dy;
                                c.center.z += dz;
                                stretched = true;
                            }
                        }
                        acadrust::EntityType::Ellipse(e) => {
                            if in_win(e.center.x, e.center.y) {
                                e.center.x += dx;
                                e.center.y += dy;
                                e.center.z += dz;
                                stretched = true;
                            }
                        }
                        acadrust::EntityType::Insert(ins) => {
                            if in_win(ins.insert_point.x, ins.insert_point.y) {
                                ins.insert_point.x += dx;
                                ins.insert_point.y += dy;
                                ins.insert_point.z += dz;
                                stretched = true;
                            }
                        }
                        acadrust::EntityType::Text(t) => {
                            if in_win(t.insertion_point.x, t.insertion_point.y) {
                                t.insertion_point.x += dx;
                                t.insertion_point.y += dy;
                                t.insertion_point.z += dz;
                                stretched = true;
                            }
                        }
                        acadrust::EntityType::MText(t) => {
                            if in_win(t.insertion_point.x, t.insertion_point.y) {
                                t.insertion_point.x += dx;
                                t.insertion_point.y += dy;
                                t.insertion_point.z += dz;
                                stretched = true;
                            }
                        }
                        acadrust::EntityType::Viewport(vp) => {
                            stretched = windows.iter().any(|(win_min, win_max)| {
                                crate::entities::viewport::stretch(
                                    vp,
                                    *win_min,
                                    *win_max,
                                    delta,
                                )
                            });
                        }
                        acadrust::EntityType::Dimension(dim) => {
                            use acadrust::entities::Dimension;
                            // Move every definition point that falls inside the
                            // window — the same points the grips expose — then
                            // refresh the stored measurement so the value tracks
                            // the stretched geometry.
                            let mv = |p: &mut acadrust::types::Vector3| {
                                if in_win(p.x, p.y) {
                                    p.x += dx;
                                    p.y += dy;
                                    p.z += dz;
                                    true
                                } else {
                                    false
                                }
                            };
                            match dim {
                                Dimension::Linear(d) => {
                                    stretched |= mv(&mut d.first_point);
                                    stretched |= mv(&mut d.second_point);
                                    stretched |= mv(&mut d.definition_point);
                                }
                                Dimension::Aligned(d) => {
                                    stretched |= mv(&mut d.first_point);
                                    stretched |= mv(&mut d.second_point);
                                    stretched |= mv(&mut d.definition_point);
                                }
                                Dimension::Radius(d) => {
                                    stretched |= mv(&mut d.angle_vertex);
                                    stretched |= mv(&mut d.definition_point);
                                }
                                Dimension::Diameter(d) => {
                                    stretched |= mv(&mut d.angle_vertex);
                                    stretched |= mv(&mut d.definition_point);
                                }
                                Dimension::Angular2Ln(d) => {
                                    stretched |= mv(&mut d.angle_vertex);
                                    stretched |= mv(&mut d.first_point);
                                    stretched |= mv(&mut d.second_point);
                                    stretched |= mv(&mut d.definition_point);
                                }
                                Dimension::Angular3Pt(d) => {
                                    stretched |= mv(&mut d.angle_vertex);
                                    stretched |= mv(&mut d.first_point);
                                    stretched |= mv(&mut d.second_point);
                                    stretched |= mv(&mut d.definition_point);
                                }
                                Dimension::Ordinate(d) => {
                                    stretched |= mv(&mut d.feature_location);
                                    stretched |= mv(&mut d.leader_endpoint);
                                }
                                Dimension::Arc(d) => {
                                    stretched |= mv(&mut d.definition_point);
                                    stretched |= mv(&mut d.first_extension_point);
                                    stretched |= mv(&mut d.second_extension_point);
                                    stretched |= mv(&mut d.center_point);
                                    if d.has_leader {
                                        stretched |= mv(&mut d.first_leader_point);
                                        stretched |= mv(&mut d.second_leader_point);
                                    }
                                }
                                Dimension::LargeRadial(d) => {
                                    stretched |= mv(&mut d.definition_point);
                                    stretched |= mv(&mut d.chord_point);
                                    stretched |= mv(&mut d.override_center);
                                    stretched |= mv(&mut d.jog_point);
                                }
                            }
                            // Pinned text follows too; the zero sentinel means
                            // "auto placement" and must not be captured by a
                            // window that happens to cover the origin.
                            let t = dim.base().text_middle_point;
                            if t.x * t.x + t.y * t.y + t.z * t.z > 1e-16 {
                                let mut t = t;
                                if mv(&mut t) {
                                    dim.base_mut().text_middle_point = t;
                                    stretched = true;
                                }
                            }
                            if stretched {
                                dim.base_mut().actual_measurement = dim.measurement();
                                stretched_dims.push(*handle);
                            }
                        }
                        _ => {
                            // Generic: move entire entity (treat as block-level)
                            stretched = false; // skip generic types
                        }
                    }
                    if stretched {
                        if let Some(before) = before {
                            self.tabs[i].scene.record_undo_before(*handle, Some(before));
                        }
                        self.tabs[i].scene.mark_entity_dirty(*handle);
                        changed_handles.push(*handle);
                        count += 1;
                    }
                }
                // A stretched dimension renders through its baked *D block when
                // one exists (file roundtrip) — drop it so tessellation falls
                // back to the live points and the next save re-bakes. (#372)
                for h in stretched_dims {
                    self.tabs[i].scene.invalidate_dim_block_recorded(h);
                }

                // Geometry was edited in place via get_entity_mut, which the
                // scene's tessellation cache doesn't observe. Re-tessellate the
                // moved entities so the viewport reflects the stretch right away
                // instead of only on the next unrelated redraw. See #95.
                if count > 0 {
                    let changes: Vec<_> = changed_handles
                        .iter()
                        .map(|&handle| (handle, crate::scene::ChangeKind::Modified))
                        .collect();
                    self.tabs[i].scene.bump_entities(&changes);
                }
                self.tabs[i].dirty = true;
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.command_line
                    .push_output(crate::tf!("STRETCH: {count} entity(ies) stretched.").as_ref());
                self.refresh_properties();
                if let Some(pending) = pending {
                    self.commit_undo_delta(i, pending);
                }
            }
            // ── EXTRUDE ────────────────────────────────────────────────────
            CmdResult::ExtrudeEntities {
                handles,
                extent,
                mode,
                taper_angle,
                color: _,
            } => {
                let delete_sources = self.delete_objects != 0;
                if handles.is_empty()
                    || handles
                        .iter()
                        .any(|handle| self.reject_locked_edit(i, *handle))
                {
                    self.tabs[i].active_cmd = None;
                    return Task::none();
                }
                use crate::command::{ExtrudeExtent, ExtrudeMode};
                use crate::modules::insert::solid3d_cmds::{
                    empty_extruded_surface, empty_solid3d,
                };
                use crate::scene::model::sweep_model;
                let path = match extent {
                    ExtrudeExtent::Path(handle) => self.tabs[i]
                        .scene
                        .document
                        .get_entity(handle)
                        .cloned()
                        .map(|entity| (handle, entity)),
                    _ => None,
                };
                if matches!(extent, ExtrudeExtent::Path(_)) && path.is_none() {
                    self.command_line
                        .push_error(crate::t!("EXTRUDE: path entity not found.").as_ref());
                    self.tabs[i].active_cmd = None;
                    return Task::none();
                }
                let pending = self.begin_undo(i, "EXTRUDE", handles.len(), true);
                let mut created_handles = Vec::new();
                let mut consumed = Vec::new();
                let mut failed = 0usize;
                for handle in &handles {
                    let Some(entity) = self.tabs[i].scene.document.get_entity(*handle).cloned() else {
                        failed += 1;
                        continue;
                    };
                    let Some((profile, closed)) = sweep_model::extrusion_profile_of(&entity) else {
                        failed += 1;
                        continue;
                    };
                    let direction = match extent {
                        ExtrudeExtent::Height(height) => profile.plane.normal().map(|normal| {
                            glam::DVec3::new(
                                normal[0] * height,
                                normal[1] * height,
                                normal[2] * height,
                            )
                        }),
                        ExtrudeExtent::Direction(direction) => Some(direction),
                        ExtrudeExtent::Path(_) => None,
                    };
                    let path_direction = path
                        .as_ref()
                        .and_then(|(_, path)| sweep_model::straight_path_direction(path))
                        .map(glam::DVec3::from_array);
                    // The creation mode controls closed profiles. Open curves
                    // always create sheet surfaces.
                    let creates_surface = matches!(mode, ExtrudeMode::Surface) || !closed;
                    let body = match (creates_surface, &path, direction) {
                        (false, Some((_, path)), _) => {
                            sweep_model::extruded_along_path(&entity, path, taper_angle)
                        }
                        (false, None, Some(direction)) => {
                            sweep_model::extruded_direction(
                                &entity,
                                direction.to_array(),
                                taper_angle,
                            )
                        }
                        (true, None, Some(direction)) => {
                            sweep_model::extruded_surface(
                                &entity,
                                direction.to_array(),
                                taper_angle,
                            )
                        }
                        (true, Some(_), _) => path_direction.and_then(|direction| {
                            sweep_model::extruded_surface(
                                &entity,
                                direction.to_array(),
                                taper_angle,
                            )
                        }),
                        _ => None,
                    };
                    let Some(body) = body else {
                        failed += 1;
                        continue;
                    };
                    let created = if creates_surface {
                        let direction = direction
                            .or(path_direction)
                            .unwrap_or(glam::DVec3::ZERO);
                        let history = path
                            .is_none()
                            .then(|| {
                                sweep_model::extrusion_history(
                                    &entity,
                                    None,
                                    direction.to_array(),
                                    taper_angle,
                                    profile.plane.origin,
                                )
                            })
                            .flatten();
                        let mut surface = empty_extruded_surface(direction, taper_angle);
                        if let (
                            Some(acadrust::objects::SolidHistoryOperation::Extrusion(value)),
                            acadrust::EntityType::Surface(entity),
                        ) = (&history, &mut surface)
                        {
                            if let Some(data) =
                                crate::scene::model::solid_history::extrusion_surface_data(value)
                            {
                                entity.surface_data = data;
                            }
                        }
                        match history {
                            Some(history) => {
                                self.add_surface_model_with_history(surface, body, history)
                            }
                            None => self.add_surface_model(surface, body),
                        }
                    } else {
                            let direction = direction.unwrap_or(glam::DVec3::ZERO);
                            let history = path
                                .as_ref()
                                .and_then(|(_, path)| {
                                    sweep_model::sweep_history(
                                        &entity,
                                        path,
                                        taper_angle,
                                        profile.plane.origin,
                                    )
                                })
                                .or_else(|| {
                                    sweep_model::extrusion_history(
                                        &entity,
                                        None,
                                        direction.to_array(),
                                        taper_angle,
                                        profile.plane.origin,
                                    )
                                })
                            .unwrap_or_else(|| crate::scene::model::solid_history::brep_op(&body));
                            self.add_solid_model(empty_solid3d(), body, history)
                    };
                    if created.is_null() {
                        failed += 1;
                    } else {
                        created_handles.push(created);
                        if delete_sources {
                            consumed.push(*handle);
                        }
                    }
                }
                if delete_sources && !created_handles.is_empty() {
                    consumed.sort_unstable_by_key(|handle| handle.value());
                    consumed.dedup();
                    self.tabs[i].scene.erase_entities(&consumed);
                }
                if !created_handles.is_empty() {
                    self.tabs[i].scene.deselect_all();
                    for handle in &created_handles {
                        self.tabs[i].scene.select_entity(*handle, true);
                    }
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(
                        crate::tf!(
                            "EXTRUDE: created %{created} object(s); %{failed} source(s) could not be extruded.",
                            created = created_handles.len(),
                            failed = failed
                        )
                        .as_ref(),
                    );
                    if let Some(pending) = pending {
                        self.commit_undo_delta(i, pending);
                    }
                } else {
                    self.command_line.push_error(crate::t!("EXTRUDE: no selected object could be extruded with the requested options.").as_ref());
                    if let Some(pending) = pending {
                        self.commit_undo_delta(i, pending);
                    }
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
            }

            CmdResult::ThickenEntities { handles, distance } => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();

                if handles.is_empty() {
                    self.command_line
                        .push_output(crate::t!("No surfaces selected.").as_ref());
                    return Task::none();
                }
                if !distance.is_finite() {
                    self.command_line.push_error(
                        crate::t!("Requires numeric distance or two points.").as_ref(),
                    );
                    return Task::none();
                }
                if distance.abs() <= f64::EPSILON {
                    return Task::none();
                }

                use crate::modules::insert::solid3d_cmds::empty_solid3d;
                let pending = self.begin_undo(i, "THICKEN", handles.len(), true);
                let mut created = 0usize;
                let mut failed = 0usize;
                let mut self_intersections = 0usize;
                for handle in handles {
                    let Some(acadrust::EntityType::Surface(surface)) =
                        self.tabs[i].scene.document.get_entity(handle)
                    else {
                        failed += 1;
                        continue;
                    };
                    let kernel_distance = if surface.kind
                        == acadrust::entities::SurfaceKind::Revolved
                    {
                        -distance
                    } else {
                        distance
                    };
                    let body = self.tabs[i]
                        .scene
                        .solid_models
                        .get(&handle)
                        .cloned()
                        .or_else(|| {
                            crate::scene::convert::solid3d_tess::kernel_surface_body(surface)
                        });
                    let Some(body) = body else {
                        failed += 1;
                        continue;
                    };
                    let solid = match cadkernel::brep::thicken(&body, kernel_distance) {
                        Ok(solid) => solid,
                        Err(cadkernel::brep::ThickenError::SelfIntersection) => {
                            failed += 1;
                            self_intersections += 1;
                            continue;
                        }
                        Err(_) => {
                            failed += 1;
                            continue;
                        }
                    };
                    let history = crate::scene::model::solid_history::brep_op(&solid);
                    if self
                        .add_solid_model(empty_solid3d(), solid, history)
                        .is_null()
                    {
                        failed += 1;
                    } else {
                        created += 1;
                    }
                }

                if created > 0 {
                    self.tabs[i].dirty = true;
                }
                if self_intersections > 0 {
                    self.command_line.push_error(&crate::tf!(
                        "{} surface(s) cannot be thickened because the offset intersects itself.",
                        self_intersections
                    ));
                }
                if failed > 0 {
                    self.command_line.push_output(&crate::tf!(
                        "THICKEN: created {} solid(s); {} surface(s) could not be thickened exactly.",
                        created, failed
                    ));
                }
                if let Some(pending) = pending {
                    self.commit_undo_delta(i, pending);
                }
                self.refresh_properties();
            }

            CmdResult::PresspullPick { handle, point, offset, multiple: _ } => {
                self.presspull_pick(handle, point, offset);
            }
            CmdResult::PresspullApply { targets, distance, color: _ } => {
                self.presspull_apply(targets, distance);
            }

            // ── REVOLVE ────────────────────────────────────────────────────
            CmdResult::RevolveEntities {
                handles,
                axis_start,
                axis_end,
                angle,
                start_angle,
                mode,
                color: _,
            } => {
                if handles.is_empty() {
                    self.tabs[i].active_cmd = None;
                    self.tabs[i].snap_result = None;
                    self.tabs[i].scene.clear_preview_wire();
                    self.restore_pre_cmd_tangent();
                    return Task::none();
                }
                let delete_sources = self.delete_objects != 0;
                use crate::command::ExtrudeMode;
                use crate::modules::insert::solid3d_cmds::{
                    empty_revolved_surface, empty_solid3d,
                };
                use crate::scene::model::sweep_model;
                let from = axis_start.to_array();
                let to = axis_end.to_array();
                let mut editable_handles = Vec::with_capacity(handles.len());
                let mut failed = 0usize;
                for handle in handles {
                    if self.reject_locked_edit(i, handle) {
                        failed += 1;
                    } else {
                        editable_handles.push(handle);
                    }
                }
                let pending = if editable_handles.is_empty() {
                    None
                } else {
                    self.begin_undo(i, "REVOLVE", editable_handles.len(), true)
                };
                let mut created_handles = Vec::new();
                let mut consumed = Vec::new();
                for handle in &editable_handles {
                    let Some(entity) = self.tabs[i].scene.document.get_entity(*handle).cloned()
                    else {
                        failed += 1;
                        continue;
                    };
                    let Some((_, closed)) = sweep_model::extrusion_profile_of(&entity) else {
                        failed += 1;
                        continue;
                    };
                    let creates_surface = mode == ExtrudeMode::Surface || !closed;
                    let created = if creates_surface {
                        let Some(body) =
                            sweep_model::revolved_surface(&entity, from, to, angle, start_angle)
                        else {
                            failed += 1;
                            continue;
                        };
                        self.add_surface_model(
                            empty_revolved_surface(
                                &entity,
                                axis_start,
                                axis_end,
                                angle,
                                start_angle,
                            ),
                            body,
                        )
                    } else {
                        let result = sweep_model::revolve_history(
                            &entity,
                            from,
                            to,
                            angle,
                            start_angle,
                        )
                        .and_then(|history| {
                            cadkernel::acis::rebuild_body(&history)
                                .ok()
                                .map(|solid| (solid, history))
                        })
                        .or_else(|| {
                            sweep_model::revolved(&entity, from, to, angle, start_angle).map(
                                |solid| {
                                    let history =
                                        crate::scene::model::solid_history::brep_op(&solid);
                                    (solid, history)
                                },
                            )
                        });
                        let Some((solid, history)) = result else {
                            failed += 1;
                            continue;
                        };
                        self.add_solid_model(empty_solid3d(), solid, history)
                    };
                    if created.is_null() {
                        failed += 1;
                    } else {
                        created_handles.push(created);
                        if delete_sources {
                            consumed.push(*handle);
                        }
                    }
                }
                if delete_sources && !created_handles.is_empty() {
                    consumed.sort_unstable_by_key(|handle| handle.value());
                    consumed.dedup();
                    self.tabs[i].scene.erase_entities(&consumed);
                }
                if !created_handles.is_empty() {
                    self.tabs[i].scene.deselect_all();
                    for handle in &created_handles {
                        self.tabs[i].scene.select_entity(*handle, true);
                    }
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(
                        crate::tf!(
                            "REVOLVE: created %{created} object(s); %{failed} source(s) could not be revolved.",
                            created = created_handles.len(),
                            failed = failed
                        )
                        .as_ref(),
                    );
                } else {
                    self.command_line.push_error(
                        crate::t!("REVOLVE: no selected object could be revolved with the requested options.")
                            .as_ref(),
                    );
                }
                if let Some(pending) = pending {
                    self.commit_undo_delta(i, pending);
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
            }
            // ── SWEEP ─────────────────────────────────────────────────────
            CmdResult::SweepEntities {
                handles,
                path_handle,
                mode,
                options,
                color: _,
            } => {
                use crate::command::ExtrudeMode;
                use crate::modules::insert::solid3d_cmds::empty_solid3d;
                use crate::scene::model::sweep_model;
                let delete_objects = self.delete_objects;
                let delete_profiles = delete_objects != 0;
                let path = self.tabs[i].scene.document.get_entity(path_handle).cloned();
                let mut profiles = Vec::new();
                let mut failed = 0usize;
                for handle in handles {
                    if handle == path_handle || self.reject_locked_edit(i, handle) {
                        failed += 1;
                        continue;
                    }
                    if let Some(entity) = self.tabs[i].scene.document.get_entity(handle).cloned() {
                        profiles.push((handle, entity));
                    } else {
                        failed += 1;
                    }
                }
                let selection = profiles.iter().map(|(_, entity)| entity.clone()).collect::<Vec<_>>();
                let options = sweep_model::sweep_selection_options(&selection, options);
                let pending = if profiles.is_empty() {
                    None
                } else {
                    self.begin_undo(i, "SWEEP", profiles.len(), true)
                };
                let mut created_handles = Vec::new();
                let mut consumed = Vec::new();
                for (handle, profile) in profiles {
                    let result = path.as_ref().zip(options).and_then(|(path, options)| {
                        let record = sweep_model::sweep_record(&profile, path, options)?;
                        let (_, _, closed) = cadkernel::acis::sweep_profile_geometry(
                            record.sweep_entity.as_ref()?, record.sweep_entity_transform,
                        ).ok()?;
                        let surface = mode == ExtrudeMode::Surface || !closed;
                        let body = cadkernel::acis::rebuild_sweep_with_mode(&record, surface).ok()?;
                        Some((body, record, surface))
                    });
                    let Some((body, record, surface)) = result else {
                        failed += 1;
                        continue;
                    };
                    let deletes_path = crate::app::delobj_deletes_auxiliary(
                        delete_objects,
                        surface,
                    );
                    if deletes_path && self.tabs[i].scene.is_layer_locked(path_handle) {
                        failed += 1;
                        continue;
                    }
                    let created = if surface {
                        self.add_surface_model(sweep_model::swept_surface_entity(&record), body)
                    } else {
                        self.add_solid_model(
                            empty_solid3d(), body,
                            acadrust::objects::SolidHistoryOperation::Sweep(record),
                        )
                    };
                    if created.is_null() {
                        failed += 1;
                    } else {
                        created_handles.push(created);
                        if delete_profiles {
                            consumed.push(handle);
                        }
                        if deletes_path {
                            consumed.push(path_handle);
                        }
                    }
                }
                if !created_handles.is_empty() {
                    consumed.sort_unstable_by_key(|handle| handle.value());
                    consumed.dedup();
                    self.tabs[i].scene.erase_entities(&consumed);
                    self.tabs[i].scene.deselect_all();
                    for handle in &created_handles {
                        self.tabs[i].scene.select_entity(*handle, true);
                    }
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(crate::tf!(
                        "SWEEP: created {created} object(s); {failed} source(s) could not be swept.",
                        created = created_handles.len(), failed = failed
                    ).as_ref());
                } else {
                    self.command_line.push_error(crate::t!("SWEEP: could not sweep the profile along the path.").as_ref());
                }
                if let Some(pending) = pending {
                    self.commit_undo_delta(i, pending);
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
            }

            // ── LOFT ──────────────────────────────────────────────────────
            CmdResult::LoftEntities { sections, guides, path, mode, options, color: _ } => {
                use crate::command::LoftSectionSelection;
                use crate::modules::insert::solid3d_cmds::empty_solid3d;
                use crate::scene::model::loft_command_model;
                let mut sources = sections.iter().flat_map(|section| match section {
                    LoftSectionSelection::Entity(handle) => vec![*handle],
                    LoftSectionSelection::Join(handles) => handles.clone(),
                    LoftSectionSelection::Point(_) => Vec::new(),
                }).collect::<Vec<_>>();
                sources.sort_unstable_by_key(|handle| handle.value());
                sources.dedup();
                let delete_objects = self.delete_objects;
                let delete_sections = delete_objects != 0;
                let section_locked = delete_sections
                    && sources.iter().any(|handle| self.tabs[i].scene.is_layer_locked(*handle));
                let available = sources.iter().chain(guides.iter()).copied().chain(path)
                    .filter_map(|handle| self.tabs[i].scene.document.get_entity(handle)
                        .cloned().map(|entity| (handle, entity))).collect::<Vec<_>>();
                let result = if section_locked {
                    Err("LOFT: a source is on a locked layer; disable source deletion or unlock it.".to_string())
                } else {
                    loft_command_model::record(&sections, &guides, path, &available, mode, options)
                        .and_then(|record| cadkernel::acis::rebuild_loft_with_options(&record).map(|body| (body, record)))
                };
                match result {
                    Ok((body, record)) => {
                        let surface = record.parameters.as_ref().is_some_and(|settings| settings.surface);
                        let delete_auxiliary = crate::app::delobj_deletes_auxiliary(
                            delete_objects,
                            surface,
                        );
                        if delete_auxiliary
                            && guides.iter().copied().chain(path)
                                .any(|handle| self.tabs[i].scene.is_layer_locked(handle))
                        {
                            self.command_line.push_error(
                                "LOFT: a source is on a locked layer; disable source deletion or unlock it.",
                            );
                            return Task::none();
                        }
                        let dirty_before = self.tabs[i].dirty;
                        let pending = self.begin_undo(i, "LOFT", 1, true);
                        let created = if surface {
                            let handle = self.add_surface_model(loft_command_model::surface_entity(&record), body);
                            if !handle.is_null() {
                                self.tabs[i].scene.create_solid_history(handle,
                                    acadrust::objects::SolidHistoryOperation::Loft(record));
                            }
                            handle
                        } else {
                            self.add_solid_model(empty_solid3d(), body,
                                acadrust::objects::SolidHistoryOperation::Loft(record))
                        };
                        if created.is_null() {
                            // The creation helper already removed its provisional
                            // result. Discard its empty undo recording as well.
                            self.tabs[i].scene.take_undo_recording();
                            self.tabs[i].dirty = dirty_before;
                            self.command_line.push_error(crate::t!("LOFT could not create a complete display. The source sections were preserved.").as_ref());
                            return Task::none();
                        } else {
                            let mut consumed = if delete_sections {
                                sources.clone()
                            } else {
                                Vec::new()
                            };
                            if delete_auxiliary {
                                consumed.extend(guides.iter().copied());
                                consumed.extend(path);
                            }
                            consumed.sort_unstable_by_key(|handle| handle.value());
                            consumed.dedup();
                            self.tabs[i].scene.erase_entities(&consumed);
                            self.tabs[i].scene.deselect_all();
                            self.tabs[i].scene.select_entity(created, true);
                            self.tabs[i].dirty = true;
                            let message = if surface {
                                crate::t!("LOFT: surface created.")
                            } else { crate::t!("LOFT: solid created.") };
                            self.command_line.push_output(message.as_ref());
                        }
                        if let Some(pending) = pending { self.commit_undo_delta(i, pending); }
                    }
                    Err(error) => {
                        self.command_line.push_error(&error);
                        return Task::none();
                    }
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.refresh_properties();
            }

            CmdResult::SolidEdgeBlend {
                handle,
                edges,
                base_face,
                value,
                other_value,
                fillet,
            } => {
                let task = self.solid_edge_blend(
                    handle,
                    &edges,
                    base_face,
                    value,
                    other_value,
                    fillet,
                );
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                return task;
            }

            CmdResult::SolidShell {
                handle,
                actions,
                distance,
            } => {
                let task = self.solid_shell(handle, &actions, distance);
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                return task;
            }

            CmdResult::SolidSubtract {
                bases,
                cutters,
                convert_meshes,
            } => {
                let task = self.solid_subtract(&bases, &cutters, convert_meshes);
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                return task;
            }

            CmdResult::SliceEntities {
                targets,
                plane,
                keep_point,
            } => {
                let task = self.solid_slice(&targets, plane, keep_point);
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                return task;
            }

            CmdResult::SliceSurfaceEntities {
                targets,
                cutter,
                keep_point,
            } => {
                let task = self.solid_slice_surface(&targets, *cutter, keep_point);
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                return task;
            }

            CmdResult::HatcheditApply {
                handle,
                name,
                scale,
                angle,
                operation,
            } => {
                if self.reject_locked_edit(i, handle) {
                    return Task::none();
                }
                if !matches!(
                    self.tabs[i].scene.document.get_entity(handle),
                    Some(acadrust::EntityType::Hatch(_))
                ) {
                    self.command_line
                        .push_error(crate::t!("HATCHEDIT: hatch entity not found.").as_ref());
                } else {
                    use crate::command::{CadCommand, HatchEditOperation};
                    if matches!(&operation,HatchEditOperation::BeginAssociate) {
                        let associative=matches!(self.tabs[i].scene.document.get_entity(handle),Some(acadrust::EntityType::Hatch(h)) if h.is_associative);
                        if associative {
                            self.command_line.push_info("HATCHEDIT: hatch is already associative.");
                            self.tabs[i].active_cmd=None;
                        }else{
                            let plane=match self.tabs[i].scene.document.get_entity(handle) {
                                Some(acadrust::EntityType::Hatch(h))=>{
                                    let storage=crate::entities::curve::ocs_plane(h.normal,h.elevation);
                                    crate::command::WorkingPlane::new(glam::DVec3::from_array(storage.origin),glam::DVec3::from_array(storage.x_axis),glam::DVec3::from_array(storage.y_axis))
                                },
                                _=>self.tabs[i].ucs_xform().working_plane(),
                            };
                            let mut sources=self.tabs[i].scene.boundary_sources_on_plane(plane,1e-6);
                            sources.remove(&handle);
                            let command=crate::modules::draw::draw::hatchedit::HatcheditCommand::for_association(handle,name,scale,angle,plane,sources);
                            self.tabs[i].scene.deselect_all();
                            self.command_line.push_info(&command.prompt());
                            self.tabs[i].active_cmd=Some(Box::new(command));
                        }
                        return Task::none();
                    }
                    if let HatchEditOperation::DrawOrderBoundary{above}=&operation {
                        let references:Vec<_>=match self.tabs[i].scene.document.get_entity(handle) {
                            Some(acadrust::EntityType::Hatch(h))=>h.paths.iter().flat_map(|p|p.boundary_handles.iter())
                                .filter(|h|self.tabs[i].scene.document.get_entity(**h).is_some()).map(|h|format!("{:X}",h.value())).collect(),
                            _=>Vec::new(),
                        };
                        self.tabs[i].active_cmd=None;
                        if references.is_empty(){self.command_line.push_info("HATCHEDIT: no associated boundary objects.");return Task::none();}
                        self.tabs[i].scene.deselect_all();self.tabs[i].scene.select_entity(handle,false);
                        let command=format!("DRAWORDER {} {}",if *above{"ABOVE"}else{"UNDER"},references.join(" "));
                        return self.dispatch_view(&command,i).unwrap_or_else(Task::none);
                    }
                    if matches!(
                        &operation,
                        HatchEditOperation::DrawOrderFront | HatchEditOperation::DrawOrderBack
                    ) {
                        let command = if matches!(&operation, HatchEditOperation::DrawOrderFront) {
                            "DRAWORDER FRONT"
                        } else {
                            "DRAWORDER BACK"
                        };
                        self.tabs[i].scene.deselect_all();
                        self.tabs[i].scene.select_entity(handle, false);
                        self.tabs[i].active_cmd = None;
                        return self.dispatch_view(command, i).unwrap_or_else(Task::none);
                    }
                    self.push_undo_snapshot(i, "HATCHEDIT");
                    match operation {
                        HatchEditOperation::Appearance { color, layer, transparency } => {
                            let layer=layer.map(|name|if name=="."{self.tabs[i].active_layer.clone()}else{name});
                            if layer.as_ref().is_some_and(|name|self.tabs[i].scene.document.layers.get(name).is_none()) {
                                self.discard_last_undo_entry(i);
                                self.command_line.push_error("HATCHEDIT: layer not found.");
                                return Task::none();
                            }
                            if let Some(entity)=self.tabs[i].scene.document.get_entity_mut(handle) {
                                let common=entity.common_mut();
                                if let Some(value)=color {common.color=value;common.color_name=None;common.color_book_handle=None;}
                                if let Some(value)=layer {common.layer=value;}
                                if let Some(value)=transparency {common.transparency=value;}
                            }
                            self.tabs[i].scene.bump_entities(&[(handle,crate::scene::ChangeKind::Modified)]);
                            self.refresh_properties();
                        }
                        HatchEditOperation::Update {
                            origin,
                            store_origin,
                            disassociate,
                            style,
                            annotative,
                        } => {
                            if store_origin {
                                if let Some((x, y)) = origin {
                                    if !self.tabs[i].scene.document.set_hatch_origin([x, y]) {
                                        self.discard_last_undo_entry(i);
                                        self.command_line.push_error("HATCHEDIT: cannot store default origin.");
                                        return Task::none();
                                    }
                                }
                            }
                            if let Some(acadrust::EntityType::Hatch(hatch)) =
                                self.tabs[i].scene.document.get_entity_mut(handle)
                            {
                                if !name.is_empty() && name != hatch.pattern.name {
                                    if let Some(entry) =
                                        crate::scene::model::hatch_patterns::find(&name)
                                    {
                                        let mut pattern = crate::scene::model::hatch_patterns::build_dxf_pattern(entry);
                                        crate::entities::hatch::scale_pattern_geometry(
                                            &mut pattern,
                                            scale.max(1.0e-6) as f64,
                                        );
                                        crate::entities::hatch::rotate_pattern_geometry(
                                            &mut pattern,
                                            (angle as f64).to_radians(),
                                        );
                                        let origin = hatch.pattern_origin();
                                        crate::entities::hatch::translate_pattern_geometry(&mut pattern, origin.x, origin.y);
                                        hatch.pattern = pattern;
                                        hatch.is_solid = matches!(
                                            entry.gpu,
                                            crate::scene::model::hatch_model::HatchPattern::Solid
                                        );
                                        hatch.pattern_type =
                                            acadrust::entities::HatchPatternType::Predefined;
                                        hatch.gradient_color.enabled = false;
                                    }
                                } else {
                                    let requested_scale = scale.max(1.0e-6) as f64;
                                    if hatch.pattern_scale > 1.0e-12 {
                                        let factor = requested_scale / hatch.pattern_scale;
                                        hatch.scale_pattern_about_origin(factor);
                                    }
                                    let requested_angle = (angle as f64).to_radians();
                                    let delta = requested_angle - hatch.pattern_angle;
                                    hatch.rotate_pattern_about_origin(delta);
                                }
                                hatch.pattern_scale = scale.max(1.0e-6) as f64;
                                hatch.pattern_angle = (angle as f64).to_radians();
                                if let Some((x, y)) = origin {
                                    hatch.set_pattern_origin(acadrust::types::Vector2::new(x, y));
                                }
                                if disassociate {
                                    for path in &mut hatch.paths {
                                        path.boundary_handles.clear();
                                        path.flags.set_external(false);
                                    }
                                    hatch.is_associative = false;
                                }
                                if let Some(style) = style {
                                    hatch.style = style;
                                }
                            }
                            if let Some(value) = annotative {
                                crate::scene::annotative::set_entity_annotative(
                                    &mut self.tabs[i].scene.document,
                                    handle,
                                    value,
                                );
                                if value {
                                    if let Some(scale_handle) =
                                        self.tabs[i].scene.creation_annotation_scale_handle()
                                    {
                                        crate::scene::annotative::create_annotation_context(
                                            &mut self.tabs[i].scene.document,
                                            handle,
                                            scale_handle,
                                        );
                                    }
                                }
                            }
                            self.tabs[i].scene.bump_entities(&[(
                                handle,
                                crate::scene::ChangeKind::Modified,
                            )]);
                        }
                        HatchEditOperation::AddBoundaries(handles) => {
                            self.tabs[i]
                                .scene
                                .edit_hatch_boundary_handles(handle, &handles, true);
                        }
                        HatchEditOperation::RemoveBoundaries(handles) => {
                            self.tabs[i]
                                .scene
                                .edit_hatch_boundary_handles(handle, &handles, false);
                        }
                        HatchEditOperation::AssociatePaths(paths) => {
                            if paths.is_empty()||paths.iter().any(|path|path.boundary_handles.is_empty()||path.boundary_handles.iter().any(|source|self.tabs[i].scene.document.get_entity(*source).is_none())) {
                                self.discard_last_undo_entry(i);
                                self.command_line.push_error("HATCHEDIT: associated boundary is no longer available.");
                                return Task::none();
                            }
                            self.tabs[i].scene.replace_hatch_association(handle,paths);
                        }
                        HatchEditOperation::RecreateBoundary { associate, region } => {
                            let source = self.tabs[i].scene.document.get_entity(handle).cloned();
                            if let Some(acadrust::EntityType::Hatch(source)) = source {
                                let storage = crate::entities::curve::ocs_plane(
                                    source.normal,
                                    source.elevation,
                                );
                                let plane = crate::command::WorkingPlane::new(
                                    glam::DVec3::from_array(storage.origin),
                                    glam::DVec3::from_array(storage.x_axis),
                                    glam::DVec3::from_array(storage.y_axis),
                                );
                                let (entities, path_groups) = if region {
                                    let loops = source.paths.iter().map(|path| {
                                        path.edges.iter().map(crate::entities::hatch::edge_curve).collect::<Option<Vec<_>>>()
                                    }).collect::<Option<Vec<_>>>();
                                    let Some(loops) = loops.filter(|loops| !loops.is_empty() && loops.iter().all(|ring| !ring.is_empty())) else {
                                        self.discard_last_undo_entry(i);
                                        self.command_line.push_error("HATCHEDIT: boundary cannot form a region.");
                                        return Task::none();
                                    };
                                    let contained = loops.iter().enumerate().map(|(inner, ring)| {
                                        let seed = ring[0].point_at(0.0);
                                        loops.iter().enumerate().map(|(outer, boundary)| {
                                            inner != outer && cadkernel::geom2d::contains(boundary, seed, cadkernel::geom2d::Tolerance::new(1e-6))
                                        }).collect::<Vec<_>>()
                                    }).collect::<Vec<_>>();
                                    let depths = contained.iter().map(|row| row.iter().filter(|inside| **inside).count()).collect::<Vec<_>>();
                                    let groups = depths.iter().enumerate().filter(|(_, depth)| **depth % 2 == 0).map(|(outer, depth)| {
                                        let mut indices = vec![outer];
                                        indices.extend((0..loops.len()).filter(|inner| depths[*inner] == *depth + 1 && contained[*inner][outer]));
                                        indices
                                    }).collect::<Vec<_>>();
                                    let entities = groups.iter().map(|indices| {
                                        let profiles = indices.iter().map(|index| loops[*index].clone()).collect::<Vec<_>>();
                                        crate::scene::model::presspull_model::region_from_loops(&profiles, plane)
                                    }).collect::<Option<Vec<_>>>();
                                    let Some(entities) = entities else {
                                        self.discard_last_undo_entry(i);
                                        self.command_line.push_error("HATCHEDIT: boundary cannot form a region.");
                                        return Task::none();
                                    };
                                    (entities, groups)
                                } else {
                                    let rings = crate::scene::hatch_boundary_rings(&source);
                                    if rings.len() != source.paths.len() {
                                        self.discard_last_undo_entry(i);
                                        self.command_line.push_error(
                                            "HATCHEDIT: boundary cannot form a polyline.",
                                        );
                                        return Task::none();
                                    }
                                    let entities = crate::scene::boundary_entities(&rings, plane);
                                    if entities.len() != source.paths.len() {
                                        self.discard_last_undo_entry(i);
                                        self.command_line.push_error(
                                            "HATCHEDIT: boundary cannot form a polyline.",
                                        );
                                        return Task::none();
                                    }
                                    let groups = (0..entities.len()).map(|index| vec![index]).collect();
                                    (entities, groups)
                                };
                                let mut path_handles = vec![None; source.paths.len()];
                                for (entity, paths) in entities.into_iter().zip(path_groups) {
                                    if let Some(boundary) = self.commit_entity_handle(entity) {
                                        for path in paths { if let Some(slot) = path_handles.get_mut(path) { *slot = Some(boundary); } }
                                    }
                                }
                                if associate { if let Some(acadrust::EntityType::Hatch(hatch)) =
                                    self.tabs[i].scene.document.get_entity_mut(handle)
                                {
                                    for (path, boundary) in hatch.paths.iter_mut().zip(path_handles.iter().copied()) {
                                        if let Some(boundary) = boundary {
                                            path.boundary_handles = vec![boundary];
                                            path.flags.set_external(true);
                                        }
                                    }
                                    hatch.is_associative = path_handles.iter().all(Option::is_some);
                                } }
                                self.tabs[i].scene.bump_entities(&[(
                                    handle,
                                    crate::scene::ChangeKind::Modified,
                                )]);
                            }
                        }
                        HatchEditOperation::Separate => {
                            let source = self.tabs[i].scene.document.get_entity(handle).cloned();
                            if let Some(acadrust::EntityType::Hatch(hatch)) = source {
                                let groups = crate::scene::separated_hatch_path_groups(&hatch);
                                if groups.len() > 1 {
                                    for paths in groups {
                                        let mut separated = hatch.clone();
                                        separated.common.handle = acadrust::Handle::NULL;
                                        separated.paths = paths;
                                        separated.is_associative = separated
                                            .paths
                                            .iter()
                                            .any(|path| !path.boundary_handles.is_empty());
                                        self.tabs[i]
                                            .scene
                                            .add_entity(acadrust::EntityType::Hatch(separated));
                                    }
                                    self.tabs[i].scene.erase_entities(&[handle]);
                                }
                            }
                        }
                        HatchEditOperation::DrawOrderFront
                        | HatchEditOperation::DrawOrderBack
                        | HatchEditOperation::DrawOrderBoundary {..}
                        | HatchEditOperation::BeginAssociate => unreachable!(),
                    }
                    self.tabs[i].dirty = true;
                    self.command_line
                        .push_output(crate::t!("HATCHEDIT: hatch updated.").as_ref());
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
            }
            CmdResult::OpenMTextEditor {
                pos,
                handle,
                initial,
                height,
                template,
            } => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.open_mtext_editor(pos, handle, &initial, height, template.map(|m| *m));
            }
            CmdResult::SuspendForMTextInput {
                pos,
                initial,
                height,
            } => {
                self.tabs[i].suspended_cmd = self.tabs[i].active_cmd.take();
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.command_mtext_input = true;
                self.pending_command_editor_text = None;
                self.open_mtext_editor(pos, None, &initial, height, None);
            }
            CmdResult::OpenTextEditor {
                pos,
                handle,
                initial,
                height,
            } => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.open_text_inline(
                    pos,
                    handle,
                    &initial,
                    height,
                    super::text_inline::TextEntityField::Text,
                    None,
                );
            }
            CmdResult::SuspendForTextInput { pos, entity } => {
                self.tabs[i].suspended_cmd = self.tabs[i].active_cmd.take();
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                let height = entity.height;
                self.open_text_inline(
                    pos,
                    None,
                    "",
                    height,
                    super::text_inline::TextEntityField::Text,
                    Some(entity),
                );
            }
            CmdResult::EditTextEntity { handle } => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.ribbon.deactivate_tool();
                return self.begin_text_edit(handle);
            }
            CmdResult::SuspendForTextEdit { handle } => {
                let is_editable =
                    crate::app::text_inline::can_edit_text(handle, &self.tabs[i].scene.document);
                if !is_editable {
                    self.command_line
                        .push_error(crate::t!("TEXTEDIT: selected entity is not text.").as_ref());
                    let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                    if let Some(p) = prompt {
                        self.command_line.push_info(&p);
                    }
                    return Task::none();
                }
                let cmd = self.tabs[i].active_cmd.take();
                self.tabs[i].suspended_cmd = cmd;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
                self.ribbon.deactivate_tool();
                return self.begin_text_edit(handle);
            }
            CmdResult::UndoDocument => {
                let active = self.tabs[i].active_cmd.take();
                self.undo_active_tab();
                self.tabs[i].active_cmd = active;
                if self.tabs[i].active_cmd.as_ref().is_some_and(|command| command.name() == "PEDIT") {
                    let entities: Vec<_> = self.tabs[i].scene.document.entities().cloned().collect();
                    if let Some(command) = self.tabs[i].active_cmd.as_mut() {
                        for entity in entities { command.inject_picked_entity(entity); }
                    }
                }
                let prompt = self.tabs[i].active_cmd.as_ref().map(|c| c.prompt());
                if let Some(p) = prompt {
                    self.command_line.push_info(&p);
                }
            }
            CmdResult::SetTexteditMode(val) => {
                self.texteditmode = val;
                let display_val = if val { 1 } else { 0 };
                self.command_line
                    .push_output(crate::tf!("TEXTEDITMODE set to {display_val}").as_ref());
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
            }
            CmdResult::EditDimensions {
                mut handles,
                operation,
            } => {
                handles.retain(|handle| {
                    !self.tabs[i].scene.is_layer_locked(*handle)
                        && matches!(
                            self.tabs[i].scene.document.get_entity(*handle),
                            Some(acadrust::EntityType::Dimension(_))
                        )
                });
                if handles.is_empty() {
                    self.command_line
                        .push_error(crate::t!("DIMEDIT: no editable dimensions were selected.").as_ref());
                } else {
                    self.push_undo_snapshot(i, "DIMEDIT");
                    for handle in &handles {
                        if let Some(acadrust::EntityType::Dimension(dimension)) =
                            self.tabs[i].scene.document.get_entity_mut(*handle)
                        {
                            use crate::command::DimensionEditOperation as Operation;
                            match &operation {
                                Operation::Home => {
                                    let base = dimension.base_mut();
                                    base.text_middle_point = acadrust::types::Vector3::ZERO;
                                    base.insertion_point = acadrust::types::Vector3::ZERO;
                                    base.text_user_positioned = false;
                                    base.text_rotation = 0.0;
                                }
                                Operation::NewText(text) => {
                                    dimension.base_mut().set_text_override(
                                        (!text.is_empty()).then_some(text.clone()),
                                    );
                                }
                                Operation::Rotate(degrees) => {
                                    dimension.base_mut().text_rotation = degrees.to_radians();
                                }
                                Operation::Oblique(degrees) => match dimension {
                                    acadrust::entities::Dimension::Linear(value) => {
                                        value.ext_line_rotation = degrees.to_radians();
                                    }
                                    acadrust::entities::Dimension::Aligned(value) => {
                                        value.ext_line_rotation = degrees.to_radians();
                                    }
                                    _ => {}
                                },
                            }
                        }
                        self.tabs[i].scene.invalidate_dim_block_recorded(*handle);
                    }
                    let changes: Vec<_> = handles
                        .iter()
                        .copied()
                        .map(|handle| (handle, crate::scene::ChangeKind::Modified))
                        .collect();
                    self.tabs[i].scene.bump_entities(&changes);
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(
                        crate::tf!("DIMEDIT: updated {} dimension(s).", handles.len()).as_ref(),
                    );
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
            }
            CmdResult::DdeditEntity { handle, new_text } => {
                if self.reject_locked_edit(i, handle) {
                    self.tabs[i].active_cmd = None;
                    return Task::none();
                }
                self.push_undo_snapshot(i, "DDEDIT");
                let mut updated = false;
                let mut is_dim = false;
                if let Some(entity) = self.tabs[i].scene.document.get_entity_mut(handle) {
                    match entity {
                        acadrust::EntityType::Text(t) => {
                            t.value = new_text;
                            updated = true;
                        }
                        acadrust::EntityType::MText(t) => {
                            t.value = new_text;
                            updated = true;
                        }
                        acadrust::EntityType::AttributeDefinition(a) => {
                            a.default_value = new_text;
                            updated = true;
                        }
                        acadrust::EntityType::AttributeEntity(a) => {
                            a.set_value(new_text);
                            updated = true;
                        }
                        acadrust::EntityType::Dimension(d) => {
                            // Empty string resets to auto-measured value; otherwise set override.
                            let base = d.base_mut();
                            base.text = new_text;
                            updated = true;
                            is_dim = true;
                        }
                        _ => {}
                    }
                }
                if is_dim {
                    // The edited override changed the dimension text; drop its
                    // stale *D block so save re-bakes it. (#181)
                    self.tabs[i].scene.invalidate_dim_block_recorded(handle);
                }
                if updated {
                    self.tabs[i].dirty = true;
                    self.command_line.push_output(crate::t!("DDEDIT: text updated.").as_ref());
                } else {
                    self.discard_last_undo_entry(i);
                    self.command_line
                        .push_error(crate::t!("DDEDIT: entity type not supported.").as_ref());
                }
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
            }
            CmdResult::ReturnPoint(_) => {
                self.tabs[i].active_cmd = None;
                self.tabs[i].snap_result = None;
                self.tabs[i].scene.clear_preview_wire();
                self.restore_pre_cmd_tangent();
            }
        }
        // When no command is running the ribbon tool button still has to
        // visually deactivate. Keyboard focus is assigned below to whichever
        // editor currently owns typed input.
        if self.tabs[i].active_cmd.is_none() {
            self.ribbon.deactivate_tool();
        }
        // The rich text canvas owns keyboard editing itself. Leaving the
        // hidden command input focused would make it consume Left/Right before
        // the editor can handle them.
        if self.mtext_editor.is_some() {
            return self.unfocus_widgets();
        }
        // The in-place TEXT editor needs keyboard focus on its own field.
        if self.text_inline.is_some() {
            return iced::widget::operation::focus(iced::widget::Id::new(
                super::view::TEXT_INLINE_ID,
            ));
        }
        self.focus_cmd_input()
    }

    /// Restore the tangent-snap / ortho state that was in effect before the command started.
    /// Recreate clipboard-dependency records (layer / linetype / text + dim
    /// style) in tab `i`'s document for any the copied entities reference but
    /// this drawing doesn't already have. Each recreated record gets a fresh
    /// handle from the target document so it can't collide with an existing
    /// one. No-op for same-document pastes (the records already exist). (#129)
    pub(super) fn merge_dependencies(
        &mut self,
        i: usize,
        deps: &crate::app::ClipboardDeps,
    ) {
        use acadrust::TableEntry;
        if deps.is_empty() {
            return;
        }
        let doc = &mut self.tabs[i].scene.document;
        for rec in &deps.layers {
            if !doc.layers.contains(rec.name()) {
                let mut r = rec.clone();
                r.set_handle(doc.allocate_handle());
                let _ = doc.layers.add(r);
            }
        }
        for rec in &deps.linetypes {
            if !doc.line_types.contains(rec.name()) {
                let mut r = rec.clone();
                r.set_handle(doc.allocate_handle());
                let _ = doc.line_types.add(r);
            }
        }
        for rec in &deps.text_styles {
            if !doc.text_styles.contains(rec.name()) {
                let mut r = rec.clone();
                r.set_handle(doc.allocate_handle());
                let _ = doc.text_styles.add(r);
            }
        }
        for rec in &deps.dim_styles {
            if !doc.dim_styles.contains(rec.name()) {
                let mut r = rec.clone();
                r.set_handle(doc.allocate_handle());
                let _ = doc.dim_styles.add(r);
            }
        }
    }

    pub(super) fn merge_clipboard_deps(&mut self, i: usize) {
        let deps = self.clipboard_deps.clone();
        self.merge_dependencies(i, &deps);
    }

    /// Recreate any block definition the pasted INSERTs reference but tab
    /// `i`'s document lacks (cross-drawing paste), so the block reference
    /// renders its geometry instead of nothing. No-op for same-document
    /// pastes. (#135)
    pub(super) fn merge_clipboard_blocks(&mut self, i: usize) {
        if self.clipboard_deps.blocks.is_empty() {
            return;
        }
        let blocks = self.clipboard_deps.blocks.clone();
        for def in blocks {
            if self.tabs[i]
                .scene
                .document
                .block_records
                .get(&def.name)
                .is_some()
            {
                continue;
            }
            self.tabs[i]
                .scene
                .define_block_raw(&def.name, def.base_point, def.entities);
        }
    }

    /// Shared paste finalize for every paste path (PASTECLIP, PASTEORIG):
    /// recreate the clipboard's dependency records and block definitions, add
    /// each entity with fresh handles (optionally transformed), recreate each
    /// entity's xdictionary graph (XCLIP filters etc.), and tessellate pasted
    /// solids. Returns the new handles, index-aligned with the clipboard
    /// (NULL where an add failed). Keeping this in one place means a new
    /// cross-drawing concern is wired once, not re-implemented per command.
    pub(super) fn finalize_paste(
        &mut self,
        i: usize,
        translate: Option<crate::command::EntityTransform>,
    ) -> Vec<Handle> {
        self.merge_clipboard_deps(i);
        self.merge_clipboard_blocks(i);
        let by_index: Vec<Handle> = self
            .clipboard
            .clone()
            .into_iter()
            .map(|mut entity| {
                if let Some(t) = &translate {
                    crate::scene::view::dispatch::apply_transform(&mut entity, t);
                }
                // A dimension draws from its baked `*D` block (baked in WCS), so
                // give the paste its own transformed copy of that block and
                // re-point it — otherwise the pasted dimension renders at the
                // source location instead of the paste point. The block was
                // snapshotted into the clipboard at copy time, so this works
                // cross-drawing too. Mirrors the in-drawing copy. (#290, #161)
                if let acadrust::EntityType::Dimension(d) = &entity {
                    let bn = d.base().block_name.clone();
                    if !bn.trim().is_empty() {
                        let subs = self
                            .clipboard_deps
                            .dim_blocks
                            .iter()
                            .find(|b| b.name.eq_ignore_ascii_case(&bn))
                            .map(|def| def.entities.clone());
                        if let Some(subs) = subs {
                            let bt = translate.clone().unwrap_or(
                                crate::command::EntityTransform::Translate(glam::DVec3::ZERO),
                            );
                            if let Some(new_bn) =
                                self.tabs[i].scene.define_transformed_block(&subs, &bt)
                            {
                                if let acadrust::EntityType::Dimension(d) = &mut entity {
                                    d.base_mut().block_name = new_bn;
                                }
                            }
                        }
                    }
                }
                self.tabs[i].scene.add_entity_clone(entity)
            })
            .collect();
        let annotation_delta = match translate {
            Some(crate::command::EntityTransform::Translate(delta)) => delta,
            _ => glam::DVec3::ZERO,
        };
        self.merge_clipboard_ext_objects(i, &by_index, annotation_delta);
                // Source handles stored in the clipboard map one-to-one to the freshly
        // pasted handles. Use that map to reconnect LEADER -> copied annotation.
        let mut handle_map = rustc_hash::FxHashMap::default();

        for (source, &copied) in self.clipboard.iter().zip(by_index.iter()) {
            if !copied.is_null() {
                handle_map.insert(source.common().handle, copied);
            }
        }

        let leader_links: Vec<(Handle, Handle)> = self
            .clipboard
            .iter()
            .filter_map(|source| {
                let acadrust::EntityType::Leader(leader) = source else {
                    return None;
                };

                let copied_leader = handle_map.get(&source.common().handle).copied()?;
                let copied_annotation = handle_map
                    .get(&leader.annotation_handle)
                    .copied()
                    .unwrap_or(Handle::NULL);

                Some((copied_leader, copied_annotation))
            })
            .collect();

        for (leader_handle, annotation_handle) in leader_links {
            if let Some(acadrust::EntityType::Leader(leader)) =
                self.tabs[i].scene.document.get_entity_mut(leader_handle)
            {
                leader.annotation_handle = annotation_handle;
            }

            let _ = self.tabs[i]
                .scene
                .sync_displayed_annotation_context(leader_handle);
        }
        // Recreate any group whose whole membership was copied, so a pasted
        // group stays grouped — cross-drawing too, since the groups were
        // snapshotted into the clipboard at copy time. `by_index` is aligned
        // with `self.clipboard`, so the source handle of each pasted entity maps
        // its clipboard clone to its new handle. Same shared `recreate_groups`
        // the in-drawing COPY path uses. (#440)
        if !self.clipboard_deps.groups.is_empty() {
            let groups = self.clipboard_deps.groups.clone();
            self.tabs[i].scene.recreate_groups(groups, &handle_map);
        }
        // Constraints wholly within the pasted selection follow it.
        self.tabs[i].scene.duplicate_sketch_constraints_for(&handle_map);
        // Incremental: `add_entity` already tessellated every pasted top-level
        // solid, and existing document solids are still cached — so only newly
        // introduced block-definition solids need building. The full rebuild
        // would clear and re-tessellate the entire document (every solid in the
        // drawing) on each paste, which is what made a large paste stall.
        self.tabs[i].scene.populate_missing_meshes_from_document();
        by_index
    }

    /// Recreate the extension-dictionary object graph (XCLIP spatial filters,
    /// attached XRecords, …) captured for each copied entity, cloning every
    /// object into this document with fresh handles, remapping all internal
    /// references, and re-pointing the pasted entity's `xdictionary_handle` at
    /// the new root. `by_index` is the paste's new entity handles, aligned with
    /// the clipboard order (NULL where the add failed). No-op without captures.
    pub(super) fn merge_clipboard_ext_objects(
        &mut self,
        i: usize,
        by_index: &[Handle],
        annotation_delta: glam::DVec3,
    ) {
        if self.clipboard_deps.ext_objects.is_empty() {
            return;
        }
        let captures = self.clipboard_deps.ext_objects.clone();
        let doc = &mut self.tabs[i].scene.document;
        for cap in &captures {
            let Some(&new_entity) = by_index.get(cap.entity_index) else {
                continue;
            };
            if new_entity.is_null() {
                continue;
            }
            if let Some(new_root) = recreate_ext_subtree(doc, cap, Some(new_entity)) {
                if let Some(e) = doc.get_entity_mut(new_entity) {
                    e.common_mut().xdictionary_handle = Some(new_root);
                }
                crate::scene::annotative::translate_annotation_contexts(
                    doc,
                    new_entity,
                    annotation_delta,
                );
            }
        }
        // The wires were tessellated before the filters existed; refresh only
        // the freshly-pasted entities whose clip object graph was attached.
        let changes: Vec<_> = by_index
            .iter()
            .copied()
            .filter(|handle| !handle.is_null())
            .map(|handle| (handle, crate::scene::ChangeKind::Modified))
            .collect();
        self.tabs[i].scene.bump_entities(&changes);
    }

    /// Recreate the captured xdictionary subtrees in this document (fresh
    /// handles, remapped references) WITHOUT an added host entity, returning
    /// `entity_index → new xdictionary root`. Used by PASTEBLOCK, which folds
    /// the clipboard into a new block definition: the caller stamps each new
    /// root onto the matching entity's `xdictionary_handle` before defining the
    /// block, so the block's nested insert keeps its XCLIP filter.
    pub(super) fn recreate_clipboard_ext_roots(
        &mut self,
        i: usize,
    ) -> std::collections::HashMap<usize, Handle> {
        let mut out = std::collections::HashMap::new();
        if self.clipboard_deps.ext_objects.is_empty() {
            return out;
        }
        let captures = self.clipboard_deps.ext_objects.clone();
        let doc = &mut self.tabs[i].scene.document;
        for cap in &captures {
            if let Some(new_root) = recreate_ext_subtree(doc, cap, None) {
                out.insert(cap.entity_index, new_root);
            }
        }
        out
    }

    fn restore_pre_cmd_tangent(&mut self) {
        if let Some(was_on) = self.pre_cmd_tangent.take() {
            if !was_on {
                self.snapper.enabled.remove(&crate::snap::SnapType::Tangent);
            }
        }
        if self.rect_suppressed_ortho {
            self.rect_suppressed_ortho = false;
            self.ortho_mode = true;
            self.polar_mode = false;
        }
    }
}

/// Clone one captured xdictionary subtree into `doc` with fresh handles,
/// remapping every internal reference (and the owning entity, when known),
/// returning the new root handle. `allocate_handle` advances the document's
/// handle counter — `next_handle()` only peeks, so reusing it would hand every
/// object the same handle and collapse the dictionary chain.
fn recreate_ext_subtree(
    doc: &mut acadrust::CadDocument,
    cap: &crate::app::ClipExtObjects,
    entity_handle: Option<Handle>,
) -> Option<Handle> {
    use std::collections::HashMap;
    let mut remap: HashMap<Handle, Handle> = HashMap::new();
    if let Some(eh) = entity_handle {
        remap.insert(cap.src_entity_handle, eh);
    }
    for (old, scale) in &cap.annotation_scales {
        let target = crate::scene::annotative::ensure_scale_object(doc, scale);
        remap.insert(*old, target);
    }
    for (old, _) in &cap.objects {
        remap.insert(*old, doc.allocate_handle());
    }
    for (old, obj) in &cap.objects {
        let mut obj = obj.clone();
        let new_h = remap[old];
        remap_object(&mut obj, new_h, &remap);
        doc.objects.insert(new_h, obj);
    }
    remap.get(&cap.root).copied()
}

/// Replace references to a clipboard entity inside one recreated extension
/// dictionary graph after its final block-owned handle becomes known.
pub(crate) fn remap_ext_subtree_reference(
    doc: &mut acadrust::CadDocument,
    root: Handle,
    source_entity: Handle,
    target_entity: Handle,
) {
    use acadrust::objects::ObjectType;
    use rustc_hash::FxHashSet;
    use std::collections::HashMap;

    let remap = HashMap::from([(source_entity, target_entity)]);
    let mut seen = FxHashSet::default();
    let mut pending = vec![root];
    while let Some(handle) = pending.pop() {
        if handle.is_null() || !seen.insert(handle) {
            continue;
        }
        let children = match doc.objects.get(&handle) {
            Some(ObjectType::Dictionary(dictionary)) => {
                let mut children: Vec<_> =
                    dictionary.entries.iter().map(|(_, child)| *child).collect();
                if let Some(extension) = dictionary.xdictionary_handle {
                    children.push(extension);
                }
                children
            }
            Some(ObjectType::DictionaryWithDefault(dictionary)) => {
                let mut children: Vec<_> =
                    dictionary.entries.iter().map(|(_, child)| *child).collect();
                children.push(dictionary.default_handle);
                children
            }
            _ => Vec::new(),
        };
        pending.extend(children);
        if let Some(mut object) = doc.objects.remove(&handle) {
            remap_object(&mut object, handle, &remap);
            doc.objects.insert(handle, object);
        }
    }
}

/// Rewrite a cloned extension-dictionary object onto fresh handles: set its own
/// handle to `new_handle` and remap its owner and any handle references it holds
/// through `remap` (a handle still in the source space stays unchanged, which is
/// correct for cross-references that point outside the captured subtree).
fn remap_object(
    obj: &mut acadrust::objects::ObjectType,
    new_handle: acadrust::Handle,
    remap: &std::collections::HashMap<acadrust::Handle, acadrust::Handle>,
) {
    use acadrust::objects::ObjectType;
    let map = |h: acadrust::Handle| remap.get(&h).copied().unwrap_or(h);
    match obj {
        ObjectType::Dictionary(d) => {
            d.handle = new_handle;
            d.owner = map(d.owner);
            for (_, h) in d.entries.iter_mut() {
                *h = map(*h);
            }
            if let Some(x) = d.xdictionary_handle.as_mut() {
                *x = map(*x);
            }
            for r in d.reactors.iter_mut() {
                *r = map(*r);
            }
        }
        ObjectType::DictionaryWithDefault(d) => {
            d.handle = new_handle;
            d.owner = map(d.owner);
            for (_, h) in d.entries.iter_mut() {
                *h = map(*h);
            }
            d.default_handle = map(d.default_handle);
        }
        ObjectType::DictionaryVariable(v) => {
            v.handle = new_handle;
            v.owner_handle = map(v.owner_handle);
        }
        ObjectType::SpatialFilter(s) => {
            s.handle = new_handle;
            s.owner = map(s.owner);
        }
        ObjectType::XRecord(x) => {
            x.handle = new_handle;
            x.owner = map(x.owner);
            for entry in &mut x.entries {
                if let acadrust::objects::XRecordValue::Handle(handle) = &mut entry.value {
                    *handle = map(*handle);
                }
            }
        }
        ObjectType::Group(g) => {
            g.handle = new_handle;
            g.owner = map(g.owner);
            for h in g.entities.iter_mut() {
                *h = map(*h);
            }
        }
        ObjectType::ObjectContextData(context) => {
            context.handle = new_handle;
            context.owner_handle = map(context.owner_handle);
            for reactor in &mut context.reactors {
                *reactor = map(*reactor);
            }
            if let Some(dictionary) = &mut context.xdictionary_handle {
                *dictionary = map(*dictionary);
            }
            context.scale = map(context.scale);
            match &mut context.kind {
                acadrust::objects::ObjectContextKind::Dim(dimension) => {
                    dimension.block = map(dimension.block);
                }
                acadrust::objects::ObjectContextKind::HatchView(hatch) => {
                    hatch.view = map(hatch.view);
                }
                acadrust::objects::ObjectContextKind::MTextAttribute(attribute) => {
                    if let Some(embedded) = &mut attribute.context {
                        embedded.owner_handle = map(embedded.owner_handle);
                        for reactor in &mut embedded.reactors {
                            *reactor = map(*reactor);
                        }
                        if let Some(dictionary) = &mut embedded.xdictionary_handle {
                            *dictionary = map(*dictionary);
                        }
                        embedded.scale = map(embedded.scale);
                    }
                }
                acadrust::objects::ObjectContextKind::MLeader(mleader) => {
                    if let Some(handle) = &mut mleader.text_style_handle {
                        *handle = map(*handle);
                    }
                    if let Some(handle) = &mut mleader.block_content_handle {
                        *handle = map(*handle);
                    }
                    if let Some(handle) = &mut mleader.scale_handle {
                        *handle = map(*handle);
                    }
                    for root in &mut mleader.leader_roots {
                        for line in &mut root.lines {
                            if let Some(handle) = &mut line.line_type_handle {
                                *handle = map(*handle);
                            }
                            if let Some(handle) = &mut line.arrowhead_handle {
                                *handle = map(*handle);
                            }
                        }
                    }
                }
                _ => {}
            }
        }
        // Other leaf object kinds don't appear in an entity xdictionary; if one
        // does, it's inserted with the fresh handle below via the caller's key,
        // but its internal owner is left as-is (best effort).
        _ => {}
    }
}

// ── DIMSPACE helper ───────────────────────────────────────────────────────────

struct DimBreakResult {
    changed: Vec<Handle>,
    message: String,
}

fn wire_segments(
    models: &[crate::scene::model::wire_model::WireModel],
) -> Vec<(glam::DVec3, glam::DVec3)> {
    let mut output = Vec::new();
    for model in models {
        for run in model.points.split(|point| !point[0].is_finite()) {
            for pair in run.windows(2) {
                let first = glam::DVec3::new(
                    pair[0][0] as f64,
                    pair[0][1] as f64,
                    pair[0][2] as f64,
                );
                let second = glam::DVec3::new(
                    pair[1][0] as f64,
                    pair[1][1] as f64,
                    pair[1][2] as f64,
                );
                if first.is_finite()
                    && second.is_finite()
                    && first.distance_squared(second) > 1.0e-18
                {
                    output.push((first, second));
                }
            }
        }
    }
    output
}

fn segment_intersection_xy(
    first: (glam::DVec3, glam::DVec3),
    second: (glam::DVec3, glam::DVec3),
) -> Option<(glam::DVec3, glam::DVec3)> {
    let gap = cadkernel::space::segment_break_gap_xy(
        [first.0.to_array(), first.1.to_array()],
        [second.0.to_array(), second.1.to_array()],
        0.25,
    )?;
    Some((glam::DVec3::from_array(gap[0]), glam::DVec3::from_array(gap[1])))
}

fn break_object_handle(document: &acadrust::CadDocument, dimension: Handle) -> Option<Handle> {
    document.objects.iter().find_map(|(handle, object)| {
        let acadrust::objects::ObjectType::DataObject(object) = object else {
            return None;
        };
        let acadrust::objects::DataObjectData::BreakData(data) = &object.data else {
            return None;
        };
        (data.dimension_reference == dimension).then_some(*handle)
    })
}

fn remove_dimension_break_data(document: &mut acadrust::CadDocument, dimension: Handle) -> bool {
    let handles: Vec<_> = document
        .objects
        .iter()
        .filter_map(|(handle, object)| match object {
            acadrust::objects::ObjectType::DataObject(object) => match &object.data {
                acadrust::objects::DataObjectData::BreakData(data)
                    if data.dimension_reference == dimension => Some(*handle),
                _ => None,
            },
            _ => None,
        })
        .collect();
    if handles.is_empty() {
        return false;
    }
    for handle in &handles {
        document.objects.remove(handle);
    }
    if let Some(dictionary_handle) = document.extension_dictionary_handle(dimension) {
        if let Some(acadrust::objects::ObjectType::Dictionary(dictionary)) =
            document.objects.get_mut(&dictionary_handle)
        {
            dictionary.entries.retain(|(name, handle)| {
                !name.eq_ignore_ascii_case("ACAD_BREAKDATA") && !handles.contains(handle)
            });
            dictionary
                .hard_owner_entries
                .retain(|name| !name.eq_ignore_ascii_case("ACAD_BREAKDATA"));
        }
    }
    true
}

fn write_dimension_break_data(
    document: &mut acadrust::CadDocument,
    dimension: Handle,
    reserved_reference: Handle,
    references: Vec<acadrust::objects::BreakPointReference>,
) -> bool {
    use acadrust::objects::{BreakData, DataObject, DataObjectData, Dictionary, ObjectType};

    if references.is_empty() {
        return remove_dimension_break_data(document, dimension);
    }
    if let Some(handle) = break_object_handle(document, dimension) {
        if let Some(ObjectType::DataObject(object)) = document.objects.get_mut(&handle) {
            object.data = DataObjectData::BreakData(BreakData {
                version: 0,
                dimension_reference: dimension,
                reserved_reference,
                point_references: references,
            });
            return true;
        }
    }

    let dictionary_handle = match document.extension_dictionary_handle(dimension) {
        Some(handle) => handle,
        None => {
            let handle = document.allocate_handle();
            let mut dictionary = Dictionary::new();
            dictionary.handle = handle;
            dictionary.owner = dimension;
            dictionary.hard_owner = true;
            document
                .objects
                .insert(handle, ObjectType::Dictionary(dictionary));
            if let Some(entity) = document.get_entity_mut(dimension) {
                entity.common_mut().xdictionary_handle = Some(handle);
            }
            handle
        }
    };

    let object_handle = document.allocate_handle();
    let mut object = DataObject::new(DataObjectData::BreakData(BreakData {
        version: 0,
        dimension_reference: dimension,
        reserved_reference,
        point_references: references,
    }));
    object.handle = object_handle;
    object.owner = dictionary_handle;
    document
        .objects
        .insert(object_handle, ObjectType::DataObject(object));
    if let Some(ObjectType::Dictionary(dictionary)) =
        document.objects.get_mut(&dictionary_handle)
    {
        dictionary
            .entries
            .retain(|(name, _)| !name.eq_ignore_ascii_case("ACAD_BREAKDATA"));
        dictionary.add_entry("ACAD_BREAKDATA", object_handle);
        dictionary.set_entry_hard_owner("ACAD_BREAKDATA", true);
    }
    true
}

fn break_reference(
    identifier: i32,
    reference_type: i32,
    first: glam::DVec3,
    second: glam::DVec3,
) -> acadrust::objects::BreakPointReference {
    acadrust::objects::BreakPointReference {
        version: 0,
        reserved: 0,
        reference_type,
        flags: 0,
        identifier,
        first_point: acadrust::types::Vector3::new(first.x, first.y, first.z),
        second_point: acadrust::types::Vector3::new(second.x, second.y, second.z),
        trailing_version: 0,
    }
}

fn apply_dimbreak(
    scene: &mut crate::scene::Scene,
    requested: &[Handle],
    operation: crate::command::DimensionBreakOperation,
) -> DimBreakResult {
    use crate::command::DimensionBreakOperation;

    let dimensions: Vec<_> = requested
        .iter()
        .copied()
        .filter(|handle| {
            matches!(
                scene.document.get_entity(*handle),
                Some(acadrust::EntityType::Dimension(_))
            ) && scene.locked_layer_name(*handle).is_none()
        })
        .collect();
    if dimensions.is_empty() {
        return DimBreakResult {
            changed: Vec::new(),
            message: crate::t!("DIMBREAK: no editable dimensions were selected.").into_owned(),
        };
    }

    if matches!(operation, DimensionBreakOperation::Remove) {
        let changed: Vec<_> = dimensions
            .into_iter()
            .filter(|handle| remove_dimension_break_data(&mut scene.document, *handle))
            .collect();
        return DimBreakResult {
            message: crate::tf!("DIMBREAK: removed breaks from {} dimension(s).", changed.len())
                .into_owned(),
            changed,
        };
    }

    let crossing_handles: Vec<Handle> = match operation {
        DimensionBreakOperation::Object(handle) => vec![handle],
        DimensionBreakOperation::Auto => scene
            .document
            .entities()
            .map(|entity| entity.common().handle)
            .filter(|handle| {
                !dimensions.contains(handle) && scene.entity_belongs_to_active_space(*handle)
            })
            .collect(),
        DimensionBreakOperation::Manual(_, _) | DimensionBreakOperation::Remove => Vec::new(),
    };
    let crossing_segments: Vec<_> = crossing_handles
        .iter()
        .flat_map(|handle| wire_segments(&scene.wire_models_for(&[*handle])))
        .collect();

    let mut pending = Vec::new();
    for dimension in &dimensions {
        let existing: Vec<_> = break_object_handle(&scene.document, *dimension)
            .and_then(|handle| scene.document.objects.get(&handle))
            .and_then(|object| match object {
                acadrust::objects::ObjectType::DataObject(object) => match &object.data {
                    acadrust::objects::DataObjectData::BreakData(data) => {
                        Some(data.point_references.clone())
                    }
                    _ => None,
                },
                _ => None,
            })
            .unwrap_or_default();
        let mut references = if matches!(operation, DimensionBreakOperation::Manual(_, _)) {
            existing
        } else {
            existing
                .into_iter()
                .filter(|reference| reference.reference_type == 2)
                .collect()
        };
        match operation {
            DimensionBreakOperation::Manual(first, second) => {
                references.push(break_reference(references.len() as i32, 2, first, second));
            }
            DimensionBreakOperation::Auto | DimensionBreakOperation::Object(_) => {
                let dimension_segments = wire_segments(&scene.wire_models_for(&[*dimension]));
                let mut intersections = Vec::new();
                for dim_segment in &dimension_segments {
                    for crossing_segment in &crossing_segments {
                        if let Some(points) =
                            segment_intersection_xy(*dim_segment, *crossing_segment)
                        {
                            let center = (points.0 + points.1) * 0.5;
                            if intersections.iter().all(
                                |(first, second): &(glam::DVec3, glam::DVec3)| {
                                    center.distance_squared((*first + *second) * 0.5) > 1.0e-8
                                },
                            ) {
                                intersections.push(points);
                            }
                        }
                    }
                }
                let start = references.len() as i32;
                references.extend(intersections.into_iter().enumerate().map(
                    |(index, points)| {
                        break_reference(start + index as i32, 1, points.0, points.1)
                    },
                ));
            }
            DimensionBreakOperation::Remove => {}
        }
        pending.push((*dimension, references));
    }

    let reserved = match operation {
        DimensionBreakOperation::Object(handle) => handle,
        _ => Handle::NULL,
    };
    let changed: Vec<_> = pending
        .into_iter()
        .filter_map(|(dimension, references)| {
            write_dimension_break_data(&mut scene.document, dimension, reserved, references)
                .then_some(dimension)
        })
        .collect();
    DimBreakResult {
        message: if changed.is_empty() {
            crate::t!("DIMBREAK: no intersections were found.").into_owned()
        } else {
            crate::tf!("DIMBREAK: updated {} dimension(s).", changed.len()).into_owned()
        },
        changed,
    }
}

fn apply_dimspace(
    scene: &mut crate::scene::Scene,
    base_h: Handle,
    others: &[Handle],
    requested_spacing: Option<f64>,
) -> bool {
    use acadrust::entities::Dimension;
    let (axis, normal, definition, auto_spacing) = match scene.document.get_entity(base_h) {
        Some(acadrust::EntityType::Dimension(dimension @ Dimension::Linear(d))) => {
            let spacing = dimension_auto_spacing(&scene.document, dimension, scene.creation_annotation_multiplier());
            (
                [d.rotation.cos(), d.rotation.sin(), 0.0],
                [d.base.normal.x, d.base.normal.y, d.base.normal.z],
                [d.definition_point.x, d.definition_point.y, d.definition_point.z],
                spacing,
            )
        }
        Some(acadrust::EntityType::Dimension(dimension @ Dimension::Aligned(d))) => {
            let spacing = dimension_auto_spacing(&scene.document, dimension, scene.creation_annotation_multiplier());
            (
                [
                    d.second_point.x - d.first_point.x,
                    d.second_point.y - d.first_point.y,
                    d.second_point.z - d.first_point.z,
                ],
                [d.base.normal.x, d.base.normal.y, d.base.normal.z],
                [d.definition_point.x, d.definition_point.y, d.definition_point.z],
                spacing,
            )
        }
        _ => return false,
    };
    let Some(frame) = cadkernel::space::dimension_spacing_frame(axis, normal, definition) else {
        return false;
    };

    let effective_spacing = requested_spacing.unwrap_or(auto_spacing);
    let mut changes = Vec::new();
    for (idx, &h) in others.iter().enumerate() {
        let target = frame.coordinate + effective_spacing * (idx + 1) as f64;
        let mut changed = false;
        if let Some(acadrust::EntityType::Dimension(dim)) = scene.document.get_entity_mut(h) {
            let slide = |p: &mut acadrust::types::Vector3| {
                let point = cadkernel::space::move_to_dimension_spacing(
                    [p.x, p.y, p.z],
                    frame,
                    target,
                );
                *p = acadrust::types::Vector3::new(point[0], point[1], point[2]);
            };
            match dim {
                Dimension::Linear(d) => {
                    slide(&mut d.definition_point);
                    d.base.definition_point = d.definition_point;
                    changed = true;
                }
                Dimension::Aligned(d) => {
                    slide(&mut d.definition_point);
                    d.base.definition_point = d.definition_point;
                    changed = true;
                }
                _ => {}
            }
        }
        if changed {
            // The dimension line moved, so its baked *D block is stale — drop it
            // so the next save re-bakes it. (#181)
            scene.invalidate_dim_block_recorded(h);
            changes.push((h, crate::scene::ChangeKind::Modified));
        }
    }
    if !changes.is_empty() {
        scene.bump_entities(&changes);
    }
    !changes.is_empty()
}

fn dimension_auto_spacing(
    document: &acadrust::CadDocument,
    dimension: &acadrust::entities::Dimension,
    annotation_multiplier: f64,
) -> f64 {
    let style = document
        .dim_styles
        .iter()
        .find(|style| style.name.eq_ignore_ascii_case(&dimension.base().style_name))
        .map(|style| crate::entities::dimension::resolved_dimension_style(style, dimension, document));
    style
        .map(|style| {
            let scale = if style.dimscale > 1.0e-9 {
                style.dimscale
            } else {
                annotation_multiplier.max(1.0e-9)
            };
            (style.dimdli.abs() * scale).max(1.0e-6)
        })
        .unwrap_or(3.75)
}

fn apply_mleader_align(
    scene: &mut crate::scene::Scene,
    handles: &[acadrust::Handle],
    from: glam::DVec3,
    to: glam::DVec3,
) -> bool {
    use cadkernel::geom2d::{closest_point, Curve, Vec2, XLine};

    let Some(direction) = Vec2::new(to.x - from.x, to.y - from.y).normalize() else {
        return false;
    };
    let line = Curve::XLine(XLine {
        base: [from.x, from.y],
        direction: direction.into(),
    });
    let mut changed = Vec::new();
    for &handle in handles {
        if let Some(acadrust::EntityType::MultiLeader(ml)) =
            scene.document.get_entity_mut(handle)
        {
            let old = ml.context.content_base_point;
            let projected = closest_point(&line, [old.x, old.y]).point;
            let new_x = projected[0];
            let new_y = projected[1];
            let shift_x = new_x - old.x;
            let shift_y = new_y - old.y;
            if shift_x.abs() <= 1.0e-12 && shift_y.abs() <= 1.0e-12 {
                continue;
            }
            ml.context.content_base_point.x = new_x;
            ml.context.content_base_point.y = new_y;
            ml.context.text_location.x += shift_x;
            ml.context.text_location.y += shift_y;
            ml.context.block_content_location.x += shift_x;
            ml.context.block_content_location.y += shift_y;
            for root in &mut ml.context.leader_roots {
                root.connection_point.x += shift_x;
                root.connection_point.y += shift_y;
            }
            changed.push((handle, crate::scene::ChangeKind::Modified));
        }
    }
    if !changed.is_empty() {
        scene.bump_entities(&changed);
    }
    !changed.is_empty()
}

fn compatible_mleader_collect_handles(
    scene: &crate::scene::Scene,
    handles: &[acadrust::Handle],
) -> Vec<acadrust::Handle> {
    let Some((base_block, base_style)) = handles.iter().find_map(|handle| {
        if scene.is_layer_locked(*handle) {
            return None;
        }
        let acadrust::EntityType::MultiLeader(leader) =
            scene.document.get_entity(*handle)?
        else {
            return None;
        };
        (leader.content_type == acadrust::entities::LeaderContentType::Block)
            .then_some((leader.block_content_handle, leader.style_handle))
    }) else {
        return Vec::new();
    };
    let mut compatible = Vec::new();
    for handle in handles.iter().copied() {
        if compatible.contains(&handle) {
            continue;
        }
        if !scene.is_layer_locked(handle)
            && matches!(
                scene.document.get_entity(handle),
                Some(acadrust::EntityType::MultiLeader(leader))
                    if leader.content_type == acadrust::entities::LeaderContentType::Block
                        && leader.block_content_handle == base_block
                        && leader.style_handle == base_style
            )
        {
            compatible.push(handle);
        }
    }
    compatible
}

fn apply_mleader_collect(
    scene: &mut crate::scene::Scene,
    handles: &[acadrust::Handle],
    point: glam::DVec3,
) -> bool {
    if handles.len() < 2 {
        return false;
    }
    let px = point.x;
    let py = point.y;
    let Some(acadrust::EntityType::MultiLeader(base)) =
        scene.document.get_entity(handles[0])
    else {
        return false;
    };
    let base_block = base.block_content_handle;
    let base_style = base.style_handle;

    let mut extra_roots: Vec<acadrust::entities::LeaderRoot> = Vec::new();
    let mut merged_handles = Vec::new();
    for &h in &handles[1..] {
        if let Some(acadrust::EntityType::MultiLeader(ml)) = scene.document.get_entity(h) {
            if ml.content_type == acadrust::entities::LeaderContentType::Block
                && ml.block_content_handle == base_block
                && ml.style_handle == base_style
            {
                let shift_x = px - ml.context.content_base_point.x;
                let shift_y = py - ml.context.content_base_point.y;
                extra_roots.extend(ml.context.leader_roots.iter().cloned().map(|mut root| {
                    root.connection_point.x += shift_x;
                    root.connection_point.y += shift_y;
                    root
                }));
                merged_handles.push(h);
            }
        }
    }
    if merged_handles.is_empty() {
        return false;
    }

    if let Some(acadrust::EntityType::MultiLeader(ml)) = scene.document.get_entity_mut(handles[0]) {
        let shift_x = px - ml.context.content_base_point.x;
        let shift_y = py - ml.context.content_base_point.y;
        for root in &mut ml.context.leader_roots {
            root.connection_point.x += shift_x;
            root.connection_point.y += shift_y;
        }
        ml.context.content_base_point.x = px;
        ml.context.content_base_point.y = py;
        ml.context.block_content_location.x = px;
        ml.context.block_content_location.y = py;
        ml.context.text_location.x = px;
        ml.context.text_location.y = py;
        for root in extra_roots {
            ml.context.leader_roots.push(root);
        }
    }

    scene.erase_entities(&merged_handles);
    scene.bump_entities(&[(handles[0], crate::scene::ChangeKind::Modified)]);
    true
}

/// MATCHPROP special properties (#281): copy every STYLE-affecting field from
/// `src` to `dst` when the destination supports it — never content (text
/// strings, block names) or placement (positions, rotations of the object
/// itself). Text formatting crosses TEXT ↔ MTEXT; the dimension style crosses
/// Dimension / Leader / Tolerance.
fn match_special_props(src: &acadrust::EntityType, dst: &mut acadrust::EntityType) {
    use acadrust::EntityType as E;

    // Text-ish source formatting.
    let text_fmt = match src {
        E::Text(t) => Some((
            t.style.clone(),
            t.height,
            Some(t.width_factor),
            Some(t.oblique_angle),
        )),
        E::MText(m) => Some((m.style.clone(), m.height, None, None)),
        E::AttributeDefinition(a) => Some((
            a.text_style.clone(),
            a.height,
            Some(a.width_factor),
            Some(a.oblique_angle),
        )),
        E::AttributeEntity(a) => Some((
            a.text_style.clone(),
            a.height,
            Some(a.width_factor),
            Some(a.oblique_angle),
        )),
        _ => None,
    };
    if let Some((style, height, wf, ob)) = text_fmt {
        match dst {
            E::Text(t) => {
                t.style = style.clone();
                t.height = height;
                if let Some(value) = wf {
                    t.width_factor = value;
                }
                if let Some(value) = ob {
                    t.oblique_angle = value;
                }
            }
            E::MText(m) => {
                m.style = style.clone();
                m.height = height;
            }
            E::AttributeDefinition(a) => {
                a.text_style = style.clone();
                a.height = height;
                if let Some(value) = wf {
                    a.width_factor = value;
                }
                if let Some(value) = ob {
                    a.oblique_angle = value;
                }
            }
            E::AttributeEntity(a) => {
                a.text_style = style;
                a.height = height;
                if let Some(value) = wf {
                    a.width_factor = value;
                }
                if let Some(value) = ob {
                    a.oblique_angle = value;
                }
            }
            _ => {}
        }
    }
    // MText-only extras (line spacing, background fill).
    if let (E::MText(sm), E::MText(dm)) = (src, dst as &mut E) {
        dm.drawing_direction = sm.drawing_direction;
        dm.line_spacing_factor = sm.line_spacing_factor;
        dm.line_spacing_style = sm.line_spacing_style;
        dm.background_fill_flags = sm.background_fill_flags;
        dm.background_scale = sm.background_scale;
        dm.background_color = sm.background_color;
        dm.background_transparency = sm.background_transparency;
    }

    // Dimension style name crosses the three dim-styled families.
    let dim_style = match src {
        E::Dimension(d) => Some(d.base().style_name.clone()),
        E::Leader(l) => Some(l.dimension_style.clone()),
        E::Tolerance(t) => Some(t.dimension_style_name.clone()),
        _ => None,
    };
    if let Some(ds) = dim_style {
        match dst {
            E::Dimension(d) => d.base_mut().style_name = ds,
            E::Leader(l) => l.dimension_style = ds,
            E::Tolerance(t) => t.dimension_style_name = ds,
            _ => {}
        }
    }

    // Hatch pattern / gradient — everything but the boundary.
    if let (E::Hatch(sh), E::Hatch(dh)) = (src, dst as &mut E) {
        dh.pattern = sh.pattern.clone();
        dh.pattern_type = sh.pattern_type;
        dh.pattern_angle = sh.pattern_angle;
        dh.pattern_scale = sh.pattern_scale;
        dh.is_solid = sh.is_solid;
        dh.is_double = sh.is_double;
        dh.style = sh.style;
        dh.gradient_color = sh.gradient_color.clone();
    }

    // Polyline display style crosses lightweight and legacy 2D polylines.
    // Per-vertex/tapered widths are resampled over the destination vertices;
    // they must not be flattened into the source's constant-width field.
    if let Some(style) = PolylineMatchStyle::from_entity(src) {
        style.apply_to(dst);
    }

    if let (E::Leader(sl), E::Leader(dl)) = (src, dst as &mut E) {
        dl.arrow_enabled = sl.arrow_enabled;
        dl.path_type = sl.path_type;
        dl.hookline_direction = sl.hookline_direction;
        dl.hookline_enabled = sl.hookline_enabled;
        dl.override_color = sl.override_color;
        dl.dimension_gap = sl.dimension_gap;
        dl.arrowhead_type = sl.arrowhead_type;
        dl.arrow_size = sl.arrow_size;
        dl.byblock_color = sl.byblock_color;
    }
    if let (E::Tolerance(st), E::Tolerance(dt)) = (src, dst as &mut E) {
        dt.dimension_style_handle = st.dimension_style_handle;
        dt.text_height = st.text_height;
        dt.dimension_gap = st.dimension_gap;
    }

    // Paper-space geometry and view position stay; viewport display/plot
    // styling and effective scale follow the source.
    if let (E::Viewport(sv), E::Viewport(dv)) = (src, dst as &mut E) {
        let scale = crate::scene::vp_effective_scale(sv.custom_scale, sv.view_height, sv.height);
        dv.custom_scale = scale;
        if scale.abs() > 1e-9 {
            dv.view_height = dv.height / scale;
        }
        dv.status.locked = sv.status.locked;
        dv.status.hide_plot = sv.status.hide_plot;
        dv.render_mode = sv.render_mode;
        dv.style_sheet = sv.style_sheet.clone();
        dv.shade_plot_mode = sv.shade_plot_mode;
        dv.background_handle = sv.background_handle;
        dv.shade_plot_handle = sv.shade_plot_handle;
        dv.visual_style_handle = sv.visual_style_handle;
        dv.default_lighting = sv.default_lighting;
        dv.default_lighting_type = sv.default_lighting_type;
        dv.brightness = sv.brightness;
        dv.contrast = sv.contrast;
        dv.ambient_color = sv.ambient_color;
    }

    if let (E::Table(st), E::Table(dt)) = (src, dst as &mut E) {
        dt.table_style_handle = st.table_style_handle;
        dt.base_style = st.base_style.clone();
        dt.override_flag = st.override_flag;
        dt.override_border_color = st.override_border_color;
        dt.override_border_line_weight = st.override_border_line_weight;
        dt.override_border_visibility = st.override_border_visibility;
        dt.legacy_style_override = st.legacy_style_override.clone();
        dt.legacy_border_colors = st.legacy_border_colors.clone();
        dt.legacy_border_line_weights = st.legacy_border_line_weights.clone();
        dt.legacy_border_visibility = st.legacy_border_visibility.clone();
    }

    if let (E::MLine(sm), E::MLine(dm)) = (src, dst as &mut E) {
        dm.style_handle = sm.style_handle;
        dm.style_name = sm.style_name.clone();
        dm.style_element_count = sm.style_element_count;
        dm.justification = sm.justification;
        dm.scale_factor = sm.scale_factor;
        // Stored segment offsets bake the old style into each vertex. Empty
        // data deliberately selects the renderer's style-derived fallback.
        for vertex in &mut dm.vertices {
            vertex.segments.clear();
        }
    }

    // MultiLeader style + every style-affecting override; content and
    // geometry (leader points, text, block handle) stay.
    if let (E::MultiLeader(sm), E::MultiLeader(dm)) = (src, dst as &mut E) {
        dm.style_handle = sm.style_handle;
        dm.path_type = sm.path_type;
        dm.line_color = sm.line_color;
        dm.line_type_handle = sm.line_type_handle;
        dm.line_weight = sm.line_weight;
        dm.enable_landing = sm.enable_landing;
        dm.enable_dogleg = sm.enable_dogleg;
        dm.dogleg_length = sm.dogleg_length;
        dm.arrowhead_handle = sm.arrowhead_handle;
        dm.arrowhead_size = sm.arrowhead_size;
        dm.text_style_handle = sm.text_style_handle;
        dm.text_color = sm.text_color;
        dm.text_frame = sm.text_frame;
        dm.text_height = sm.text_height;
        dm.text_left_attachment = sm.text_left_attachment;
        dm.text_right_attachment = sm.text_right_attachment;
        dm.text_top_attachment = sm.text_top_attachment;
        dm.text_bottom_attachment = sm.text_bottom_attachment;
        dm.text_attachment_direction = sm.text_attachment_direction;
        dm.text_attachment_point = sm.text_attachment_point;
        dm.text_alignment = sm.text_alignment;
        dm.text_angle_type = sm.text_angle_type;
        dm.text_direction_negative = sm.text_direction_negative;
        dm.text_align_in_ipe = sm.text_align_in_ipe;
        dm.block_content_color = sm.block_content_color;
        dm.block_connection_type = sm.block_connection_type;
        dm.block_scale = sm.block_scale;
        dm.scale_factor = sm.scale_factor;
        dm.property_override_flags = sm.property_override_flags;
        dm.enable_annotation_scale = sm.enable_annotation_scale;
        dm.extend_leader_to_text = sm.extend_leader_to_text;
        dm.arrowhead_overrides = sm.arrowhead_overrides.clone();

        let sc = &sm.context;
        let dc = &mut dm.context;
        dc.scale_factor = sc.scale_factor;
        dc.text_height = sc.text_height;
        dc.text_width = sc.text_width;
        dc.text_boundary_height = sc.text_boundary_height;
        dc.line_spacing_factor = sc.line_spacing_factor;
        dc.line_spacing_style = sc.line_spacing_style;
        dc.text_color = sc.text_color;
        dc.text_attachment_point = sc.text_attachment_point;
        dc.text_flow_direction = sc.text_flow_direction;
        dc.text_alignment = sc.text_alignment;
        dc.text_left_attachment = sc.text_left_attachment;
        dc.text_right_attachment = sc.text_right_attachment;
        dc.text_top_attachment = sc.text_top_attachment;
        dc.text_bottom_attachment = sc.text_bottom_attachment;
        dc.text_height_automatic = sc.text_height_automatic;
        dc.word_break = sc.word_break;
        dc.text_style_handle = sc.text_style_handle;
        dc.block_content_scale = sc.block_content_scale;
        dc.block_content_color = sc.block_content_color;
        dc.block_connection_type = sc.block_connection_type;
        dc.column_type = sc.column_type;
        dc.column_width = sc.column_width;
        dc.column_gutter = sc.column_gutter;
        dc.column_flow_reversed = sc.column_flow_reversed;
        dc.column_sizes = sc.column_sizes.clone();
        dc.background_fill_enabled = sc.background_fill_enabled;
        dc.background_mask_fill_on = sc.background_mask_fill_on;
        dc.background_fill_color = sc.background_fill_color;
        dc.background_scale_factor = sc.background_scale_factor;
        dc.background_transparency = sc.background_transparency;
        dc.arrowhead_size = sc.arrowhead_size;
        dc.landing_gap = sc.landing_gap;
        dc.scale_handle = sc.scale_handle;
    }

    // External-reference identity, placement and clip geometry stay. Only
    // display controls/appearance are matched.
    if let (E::RasterImage(si), E::RasterImage(di)) = (src, dst as &mut E) {
        di.flags = si.flags;
        di.clipping_enabled = si.clipping_enabled;
        di.brightness = si.brightness;
        di.contrast = si.contrast;
        di.fade = si.fade;
        di.clip_boundary.clip_mode = si.clip_boundary.clip_mode;
    }
    if let (E::Wipeout(sw), E::Wipeout(dw)) = (src, dst as &mut E) {
        dw.flags = sw.flags;
        dw.clipping_enabled = sw.clipping_enabled;
        dw.brightness = sw.brightness;
        dw.contrast = sw.contrast;
        dw.fade = sw.fade;
        dw.clip_mode = sw.clip_mode;
    }
    if let (E::Underlay(su), E::Underlay(du)) = (src, dst as &mut E) {
        du.flags = su.flags;
        du.contrast = su.contrast;
        du.fade = su.fade;
        du.clip_inverted = su.clip_inverted;
    }
}

struct PolylineMatchStyle {
    plinegen: bool,
    widths: Vec<(f64, f64)>,
}

impl PolylineMatchStyle {
    fn from_entity(entity: &acadrust::EntityType) -> Option<Self> {
        use acadrust::EntityType as E;

        match entity {
            E::LwPolyline(poly) => {
                let widths = if poly.vertices.is_empty() {
                    vec![(poly.constant_width, poly.constant_width)]
                } else {
                    poly.vertices
                        .iter()
                        .map(|v| {
                            (
                                width_or_default(v.start_width, poly.constant_width),
                                width_or_default(v.end_width, poly.constant_width),
                            )
                        })
                        .collect()
                };
                Some(Self {
                    plinegen: poly.plinegen,
                    widths,
                })
            }
            E::Polyline2D(poly) => {
                let widths = if poly.vertices.is_empty() {
                    vec![(poly.start_width, poly.end_width)]
                } else {
                    poly.vertices
                        .iter()
                        .map(|v| {
                            (
                                width_or_default(v.start_width, poly.start_width),
                                width_or_default(v.end_width, poly.end_width),
                            )
                        })
                        .collect()
                };
                Some(Self {
                    plinegen: poly.flags.bits()
                        & acadrust::entities::PolylineFlags::LINETYPE_CONTINUOUS.bits()
                        != 0,
                    widths,
                })
            }
            _ => None,
        }
    }

    fn apply_to(&self, entity: &mut acadrust::EntityType) {
        use acadrust::EntityType as E;

        match entity {
            E::LwPolyline(poly) => {
                poly.plinegen = self.plinegen;
                let sampled = resample_widths(&self.widths, poly.vertices.len());
                let first = sampled.first().copied().unwrap_or((0.0, 0.0));
                let can_use_constant = widths_are_same(&sampled) && nearly_equal(first.0, first.1);
                poly.constant_width = if can_use_constant { first.0 } else { 0.0 };
                for (vertex, (start, end)) in poly.vertices.iter_mut().zip(sampled) {
                    if can_use_constant {
                        vertex.start_width = 0.0;
                        vertex.end_width = 0.0;
                    } else {
                        vertex.start_width = start;
                        vertex.end_width = end;
                    }
                }
            }
            E::Polyline2D(poly) => {
                let mut bits = poly.flags.bits();
                let flag = acadrust::entities::PolylineFlags::LINETYPE_CONTINUOUS.bits();
                if self.plinegen {
                    bits |= flag;
                } else {
                    bits &= !flag;
                }
                poly.flags = acadrust::entities::PolylineFlags::from_bits(bits);
                let sampled = resample_widths(&self.widths, poly.vertices.len());
                let first = sampled.first().copied().unwrap_or((0.0, 0.0));
                let can_use_defaults = widths_are_same(&sampled);
                if can_use_defaults {
                    poly.start_width = first.0;
                    poly.end_width = first.1;
                } else {
                    poly.start_width = 0.0;
                    poly.end_width = 0.0;
                }
                for (vertex, (start, end)) in poly.vertices.iter_mut().zip(sampled) {
                    if can_use_defaults {
                        vertex.start_width = 0.0;
                        vertex.end_width = 0.0;
                    } else {
                        vertex.start_width = start;
                        vertex.end_width = end;
                    }
                }
            }
            _ => {}
        }
    }
}

fn width_or_default(value: f64, default: f64) -> f64 {
    if value.abs() <= 1e-12 {
        default
    } else {
        value
    }
}

fn nearly_equal(a: f64, b: f64) -> bool {
    (a - b).abs() <= 1e-9
}

fn widths_are_same(widths: &[(f64, f64)]) -> bool {
    let Some(first) = widths.first() else {
        return true;
    };
    widths
        .iter()
        .all(|value| nearly_equal(value.0, first.0) && nearly_equal(value.1, first.1))
}

fn resample_widths(source: &[(f64, f64)], count: usize) -> Vec<(f64, f64)> {
    if count == 0 || source.is_empty() {
        return Vec::new();
    }
    if count == 1 || source.len() == 1 {
        return vec![source[0]; count];
    }
    (0..count)
        .map(|index| {
            let source_index = index.saturating_mul(source.len() - 1) / count.saturating_sub(1);
            source[source_index]
        })
        .collect()
}

#[cfg(test)]
mod command_replacement_tests {
    use super::*;
    use acadrust::entities::{Circle, Line};
    use acadrust::types::Vector3;

    #[test]
    fn one_to_one_edits_keep_identity_but_type_changes_do_not() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let tab = app.active_tab;
        let handle = app.tabs[tab].scene.add_entity(acadrust::EntityType::Line(
            Line::from_points(Vector3::ZERO, Vector3::new(1.0, 0.0, 0.0)),
        ));
        let owner = app.tabs[tab].scene.document.get_entity(handle).unwrap().common().owner_handle;

        let kept = app.replace_command_entity(tab, handle, vec![acadrust::EntityType::Line(
            Line::from_points(Vector3::ZERO, Vector3::new(3.0, 0.0, 0.0)),
        )]);
        assert_eq!(kept, vec![handle]);
        let edited = app.tabs[tab].scene.document.get_entity(handle).unwrap();
        assert_eq!(edited.common().owner_handle, owner);
        assert!(matches!(edited, acadrust::EntityType::Line(line) if line.end.x == 3.0));

        let allocated = app.replace_command_entity(tab, handle,
            vec![acadrust::EntityType::Circle(Circle::from_coords(0.0, 0.0, 0.0, 2.0))]);
        assert_eq!(allocated.len(), 1);
        assert_ne!(allocated[0], handle);
        assert!(app.tabs[tab].scene.document.get_entity(handle).is_none());
    }
}

#[cfg(test)]
mod sketch_constraint_undo_tests {
    use super::*;
    use crate::scene::sketch_constraints::{ConstraintKind, SketchRef, SketchScope};

    fn add_line(app: &mut OpenCADStudio, x1: f64, y1: f64, x2: f64, y2: f64) -> Handle {
        app.tabs[app.active_tab]
            .scene
            .add_entity(acadrust::EntityType::Line(acadrust::entities::Line::from_points(
                acadrust::types::Vector3::new(x1, y1, 0.0),
                acadrust::types::Vector3::new(x2, y2, 0.0),
            )))
    }

    fn line_angle_deg(app: &OpenCADStudio, handle: Handle) -> f64 {
        match app.tabs[app.active_tab].scene.document.get_entity(handle) {
            Some(acadrust::EntityType::Line(l)) => (l.end.y - l.start.y).atan2(l.end.x - l.start.x).to_degrees(),
            other => panic!("expected a Line, got {other:?}"),
        }
    }

    /// Constraint state and solved geometry share one undo/redo transaction.
    #[test]
    fn adding_a_constraint_is_undoable_and_redoable_atomically() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let line = add_line(&mut app, 0.0, 0.0, 10.0, 3.0);
        let original_angle = line_angle_deg(&app, line);
        assert!((original_angle - 16.699244).abs() < 1e-3);

        let _ = app.apply_cmd_result(CmdResult::AddSketchConstraint {
            kind: ConstraintKind::Horizontal,
            refs: vec![SketchRef::whole(line)],
            driving_param: None,
            label: "Horizontal constraint",
        });
        assert!(line_angle_deg(&app, line).abs() < 1e-6, "constraint should have leveled the line");
        assert_eq!(
            app.tabs[app.active_tab].scene.sketch_constraint_set(SketchScope::ModelSpace).unwrap().constraints.len(),
            1
        );

        app.undo_steps(1);
        assert_eq!(
            app.tabs[app.active_tab]
                .scene
                .sketch_constraint_set(SketchScope::ModelSpace)
                .map(|s| s.constraints.len())
                .unwrap_or(0),
            0,
            "undo should remove the constraint record"
        );
        assert!(
            (line_angle_deg(&app, line) - original_angle).abs() < 1e-3,
            "undo should restore the pre-constraint angle"
        );

        app.redo_steps(1);
        assert!(line_angle_deg(&app, line).abs() < 1e-6, "redo should re-level the line");
        assert_eq!(
            app.tabs[app.active_tab].scene.sketch_constraint_set(SketchScope::ModelSpace).unwrap().constraints.len(),
            1,
            "redo should restore the constraint record"
        );
    }

    /// Drawing commands must not create sketch constraints implicitly.
    #[test]
    fn drawing_a_line_onto_an_existing_endpoint_does_not_add_a_constraint() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let _existing = add_line(&mut app, 0.0, 0.0, 5.0, 0.0);

        let new_line = acadrust::EntityType::Line(acadrust::entities::Line::from_points(
            acadrust::types::Vector3::new(5.0, 0.0, 0.0), // exactly on `existing`'s end point
            acadrust::types::Vector3::new(10.0, 0.0, 0.0),
        ));
        app.tabs[app.active_tab].active_cmd = Some(Box::new(crate::modules::draw::draw::line::LineCommand::new()));
        let _ = app.apply_cmd_result(CmdResult::CommitEntity(new_line));

        assert_eq!(
            app.tabs[app.active_tab]
                .scene
                .sketch_constraint_set(SketchScope::ModelSpace)
                .map(|s| s.constraints.len())
                .unwrap_or(0),
            0,
            "a drawing command must not add an implicit constraint"
        );
    }

    /// Conflict resolution removes one flagged constraint and is undoable.
    #[test]
    fn resolve_one_sketch_conflict_removes_a_flagged_constraint_and_is_undoable() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let line = add_line(&mut app, 0.0, 0.0, 10.0, 3.0);

        let _ = app.apply_cmd_result(CmdResult::AddSketchConstraint {
            kind: ConstraintKind::Horizontal,
            refs: vec![SketchRef::whole(line)],
            driving_param: None,
            label: "Horizontal constraint",
        });
        let _ = app.apply_cmd_result(CmdResult::AddSketchConstraint {
            kind: ConstraintKind::Horizontal,
            refs: vec![SketchRef::whole(line)],
            driving_param: None,
            label: "Horizontal constraint",
        }); // exact duplicate — flagged redundant once bumped
        app.tabs[app.active_tab].scene.bump_entities(&[(line, crate::scene::ChangeKind::Modified)]);

        let set = app.tabs[app.active_tab].scene.sketch_constraint_set(SketchScope::ModelSpace).unwrap();
        assert_eq!(set.constraints.len(), 2);
        assert_eq!(set.conflicts.len(), 1, "the duplicate should have been flagged");

        app.resolve_one_sketch_conflict();
        let set = app.tabs[app.active_tab].scene.sketch_constraint_set(SketchScope::ModelSpace).unwrap();
        assert_eq!(set.constraints.len(), 1, "one of the two duplicates should have been removed");

        app.undo_steps(1);
        let set = app.tabs[app.active_tab].scene.sketch_constraint_set(SketchScope::ModelSpace).unwrap();
        assert_eq!(set.constraints.len(), 2, "undo should restore the removed constraint");
    }

    /// `named_parameters_design.md` stage 4: applying the PARAMETERS editor's
    /// working buffer both defines the parameter and re-solves whatever
    /// constraint already references it by name — the entire point of a
    /// *named* parameter, not just data plumbing.
    #[test]
    fn applying_named_parameter_rows_defines_and_resolves_referencing_constraints() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let line = add_line(&mut app, 0.0, 0.0, 10.0, 0.0);

        // The constraint is added *before* the parameter exists -- allowed,
        // same as `ParameterTable::set`'s own forward-reference tolerance;
        // it just doesn't resolve to anything until the parameter is defined.
        let _ = app.apply_cmd_result(CmdResult::AddSketchConstraint {
            kind: ConstraintKind::Distance,
            refs: vec![SketchRef::point(line, 0), SketchRef::point(line, 1)],
            driving_param: Some(crate::scene::named_parameters::DrivingValue::Named("target_len".to_string())),
            label: "Distance constraint",
        });

        app.named_parameter_editor_rows =
            vec![crate::ui::window::named_parameters::ParamEditorRow { name: "target_len".to_string(), formula: "8".to_string() }];
        app.apply_named_parameter_editor_rows();

        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("target_len"), Ok(8.0));
        let (start, end) = match app.tabs[app.active_tab].scene.document.get_entity(line) {
            Some(acadrust::EntityType::Line(l)) => (l.start, l.end),
            other => panic!("expected a Line, got {other:?}"),
        };
        let len = ((end.x - start.x).powi(2) + (end.y - start.y).powi(2)).sqrt();
        assert!((len - 8.0).abs() < 1e-6, "length should track the applied parameter, got {len}");

        // Redefining the parameter and re-applying should ripple again.
        app.named_parameter_editor_rows[0].formula = "3".to_string();
        app.apply_named_parameter_editor_rows();
        let (start, end) = match app.tabs[app.active_tab].scene.document.get_entity(line) {
            Some(acadrust::EntityType::Line(l)) => (l.start, l.end),
            other => panic!("expected a Line, got {other:?}"),
        };
        let len = ((end.x - start.x).powi(2) + (end.y - start.y).powi(2)).sqrt();
        assert!((len - 3.0).abs() < 1e-6, "length should track the redefined parameter, got {len}");

        app.undo_steps(1);
        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("target_len"), Ok(8.0));
        let length_after_undo = match app.tabs[app.active_tab].scene.document.get_entity(line) {
            Some(acadrust::EntityType::Line(line)) => line.length(),
            other => panic!("expected a Line, got {other:?}"),
        };
        assert!((length_after_undo - 8.0).abs() < 1e-6);

        app.redo_steps(1);
        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("target_len"), Ok(3.0));
    }

    /// End-to-end through the actual `Message` handlers a Properties-panel
    /// click/keystroke would fire — not `apply_named_parameter_editor_rows`
    /// directly — covering the whole Parameters-section lifecycle: add,
    /// rename, redefine, and confirm a referencing constraint re-solves
    /// after each commit (not just after a whole-table Apply, since this
    /// path commits per field).
    #[test]
    fn properties_panel_parameter_row_add_rename_redefine_and_delete() {
        use crate::ui::window::named_parameters::ParamField;

        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let line = add_line(&mut app, 0.0, 0.0, 10.0, 0.0);
        let _ = app.apply_cmd_result(CmdResult::AddSketchConstraint {
            kind: ConstraintKind::Distance,
            refs: vec![SketchRef::point(line, 0), SketchRef::point(line, 1)],
            driving_param: Some(crate::scene::named_parameters::DrivingValue::Named("len".to_string())),
            label: "Distance constraint",
        });

        // Add: the first row is auto-named "param1".
        let _ = app.update(Message::PropParamAddNew);
        assert!(app.tabs[app.active_tab].scene.named_parameters().contains("param1"));
        let index = app.tabs[app.active_tab].scene.named_parameters().iter().position(|p| p.name == "param1").unwrap();

        // Rename param1 -> len (commit-on-submit, not per keystroke: input
        // alone must not touch the table yet).
        let _ = app.update(Message::PropParamInput { index, field: ParamField::Name, value: "len".to_string() });
        assert!(app.tabs[app.active_tab].scene.named_parameters().contains("param1"), "typing alone must not commit");
        let _ = app.update(Message::PropParamCommit { index, field: ParamField::Name });
        assert!(!app.tabs[app.active_tab].scene.named_parameters().contains("param1"));
        assert!(app.tabs[app.active_tab].scene.named_parameters().contains("len"));

        // Redefine its formula to 8 and confirm the Distance constraint
        // (already referencing "len" by name, defined before this) re-solves.
        let _ = app.update(Message::PropParamInput { index, field: ParamField::Formula, value: "8".to_string() });
        let _ = app.update(Message::PropParamCommit { index, field: ParamField::Formula });
        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("len"), Ok(8.0));
        let (start, end) = match app.tabs[app.active_tab].scene.document.get_entity(line) {
            Some(acadrust::EntityType::Line(l)) => (l.start, l.end),
            other => panic!("expected a Line, got {other:?}"),
        };
        let len = ((end.x - start.x).powi(2) + (end.y - start.y).powi(2)).sqrt();
        assert!((len - 8.0).abs() < 1e-6, "length should track the redefined parameter, got {len}");

        // Delete: the row is gone from the table.
        let _ = app.update(Message::PropParamDelete(index));
        assert!(!app.tabs[app.active_tab].scene.named_parameters().contains("len"));
    }

    /// A Constraints-section row click selects every entity the constraint
    /// references, replacing whatever was selected before.
    #[test]
    fn properties_panel_constraint_link_click_selects_its_entities() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let a = add_line(&mut app, 0.0, 0.0, 10.0, 0.0);
        let b = add_line(&mut app, 0.0, 5.0, 10.0, 5.0);
        let unrelated = add_line(&mut app, 20.0, 20.0, 30.0, 20.0);
        let _ = app.apply_cmd_result(CmdResult::AddSketchConstraint {
            kind: ConstraintKind::Parallel,
            refs: vec![SketchRef::whole(a), SketchRef::whole(b)],
            driving_param: None,
            label: "Parallel constraint",
        });
        app.tabs[app.active_tab].scene.select_entity(unrelated, true);

        let _ = app.update(Message::PropConstraintLinkClick(vec![a, b]));

        let selected: std::collections::HashSet<Handle> =
            app.tabs[app.active_tab].scene.selected_entities().into_iter().map(|(h, _)| h).collect();
        assert_eq!(selected, std::collections::HashSet::from([a, b]));
    }

    /// A row that fails to validate (here, a formula that doesn't parse)
    /// must not silently vanish or corrupt the table: it's reported as an
    /// error and simply isn't added, while a valid row alongside it still
    /// commits — the same isolate-the-failure treatment
    /// `ParameterTable::resolve_all` already gives a bad reference.
    #[test]
    fn applying_a_row_with_a_malformed_formula_reports_an_error_and_keeps_the_good_row() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);

        app.named_parameter_editor_rows = vec![
            crate::ui::window::named_parameters::ParamEditorRow { name: "good".to_string(), formula: "10".to_string() },
            crate::ui::window::named_parameters::ParamEditorRow { name: "bad".to_string(), formula: "1 +".to_string() },
        ];
        app.apply_named_parameter_editor_rows();

        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("good"), Ok(10.0));
        assert!(!app.tabs[app.active_tab].scene.named_parameters().contains("bad"), "a malformed row must not be added");
        assert!(
            app.command_line.history.iter().any(|e| e.kind == crate::ui::command_line::EntryKind::Error),
            "a malformed row must be reported as an error, not silently dropped"
        );
    }

    /// Two rows typed with the same name must not silently collapse into
    /// "whichever `set` call happens last wins" — both are refused, and an
    /// unrelated row still commits normally.
    #[test]
    fn applying_rows_with_a_duplicate_name_refuses_both_and_keeps_the_unrelated_row() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);

        app.named_parameter_editor_rows = vec![
            crate::ui::window::named_parameters::ParamEditorRow { name: "x".to_string(), formula: "1".to_string() },
            crate::ui::window::named_parameters::ParamEditorRow { name: "x".to_string(), formula: "2".to_string() },
            crate::ui::window::named_parameters::ParamEditorRow { name: "y".to_string(), formula: "3".to_string() },
        ];
        app.apply_named_parameter_editor_rows();

        assert!(!app.tabs[app.active_tab].scene.named_parameters().contains("x"), "a duplicated name must not be added at all");
        assert_eq!(app.tabs[app.active_tab].scene.named_parameters().resolve("y"), Ok(3.0));
        assert!(app.command_line.history.iter().any(|e| e.kind == crate::ui::command_line::EntryKind::Error));
    }

    /// Two endpoint picks resolve to a Coincident constraint.
    #[test]
    fn coincident_command_resolves_two_picked_points_into_a_constraint() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let a = add_line(&mut app, 0.0, 0.0, 5.0, 0.0);
        let b = add_line(&mut app, 20.0, 0.0, 20.0, 5.0); // deliberately far from `a`, so the two picks are unambiguous

        let _ = app.apply_cmd_result(CmdResult::AddCoincidentConstraint {
            point_a: glam::DVec3::new(5.0, 0.0, 0.0),  // a's end
            point_b: glam::DVec3::new(20.0, 0.0, 0.0), // b's start
            label: "Coincident constraint",
        });

        let set = app.tabs[app.active_tab].scene.sketch_constraint_set(SketchScope::ModelSpace).expect("a constraint set should exist");
        assert_eq!(set.constraints.len(), 1);
        let c = &set.constraints[0];
        assert_eq!(c.kind, ConstraintKind::Coincident);
        let entities: Vec<Handle> = c.refs.iter().map(|r| r.entity).collect();
        assert!(entities.contains(&a) && entities.contains(&b), "the constraint should reference both lines");
    }

    /// A pick that doesn't land near any real point (no object snap match)
    /// must not add a constraint — it should report an error and leave the
    /// scope untouched rather than silently constraining the wrong thing.
    #[test]
    fn coincident_command_reports_an_error_when_a_pick_misses() {
        let mut app = OpenCADStudio::new_for_test();
        let _ = app.automation_op(r#"{"op":"new"}"#);
        let _a = add_line(&mut app, 0.0, 0.0, 5.0, 0.0);

        let _ = app.apply_cmd_result(CmdResult::AddCoincidentConstraint {
            point_a: glam::DVec3::new(5.0, 0.0, 0.0), // a's end — a real point
            point_b: glam::DVec3::new(500.0, 500.0, 0.0), // nowhere near anything
            label: "Coincident constraint",
        });

        assert_eq!(
            app.tabs[app.active_tab]
                .scene
                .sketch_constraint_set(SketchScope::ModelSpace)
                .map(|s| s.constraints.len())
                .unwrap_or(0),
            0,
            "a missed pick must not add a constraint"
        );
    }
}

#[cfg(all(test, not(target_arch = "wasm32")))]
mod delobj_tests {
    use super::*;
    use acadrust::types::Vector3;

    fn sweep_source_presence(value: i16, mode: crate::command::ExtrudeMode) -> (bool, bool) {
        let mut app = OpenCADStudio::new_for_test();
        app.automation_op(r#"{"op":"new"}"#);
        let i = app.active_tab;
        let mut circle = acadrust::Circle::new();
        circle.radius = 2.0;
        let profile = app.tabs[i]
            .scene
            .add_entity(acadrust::EntityType::Circle(circle));
        let path = app.tabs[i].scene.add_entity(acadrust::EntityType::Line(
            acadrust::Line::from_points(
                Vector3::new(0.0, 0.0, 0.0),
                Vector3::new(0.0, 0.0, 5.0),
            ),
        ));
        app.delete_objects = value;

        let _ = app.apply_cmd_result(CmdResult::SweepEntities {
            handles: vec![profile],
            path_handle: path,
            mode,
            options: crate::command::SweepOptions::default(),
            color: [1.0; 4],
        });

        let created = app.tabs[i].scene.document.entities().any(|entity| match mode {
            crate::command::ExtrudeMode::Solid => {
                matches!(entity, acadrust::EntityType::Solid3D(_))
            }
            crate::command::ExtrudeMode::Surface => {
                matches!(entity, acadrust::EntityType::Surface(_))
            }
        });
        assert!(created, "SWEEP must produce the requested result");
        (
            app.tabs[i].scene.document.get_entity(profile).is_some(),
            app.tabs[i].scene.document.get_entity(path).is_some(),
        )
    }

    #[test]
    fn sweep_applies_all_four_source_deletion_modes() {
        let solid_expectations = [(true, true), (false, true), (false, false), (false, false)];
        for (value, expected) in solid_expectations.into_iter().enumerate() {
            assert_eq!(
                sweep_source_presence(value as i16, crate::command::ExtrudeMode::Solid),
                expected,
            );
        }
        assert_eq!(
            sweep_source_presence(2, crate::command::ExtrudeMode::Surface),
            (false, false),
        );
        assert_eq!(
            sweep_source_presence(3, crate::command::ExtrudeMode::Surface),
            (false, true),
        );
    }
}

#[cfg(all(test, not(target_arch = "wasm32")))]
mod thicken_tests {
    use super::*;
    use acadrust::entities::{Surface, SurfaceKind};
    use cadkernel::geom2d::{Circle, Curve, NurbsCurve};
    use cadkernel::space::{Parameterization, Plane};

    #[test]
    fn thicken_preserves_sources_and_round_trips_results_with_one_undo() {
        let mut app = OpenCADStudio::new_for_test();
        app.automation_op(r#"{"op":"new"}"#);
        let body = cadkernel::brep::planar_region(Plane::XY, &[
            vec![Curve::Circle(Circle { centre: [0.0; 2], radius: 3.0 })],
        ]).unwrap();
        let source = app.add_surface_model(acadrust::EntityType::Surface(Surface::new(SurfaceKind::Plane)), body);
        assert!(!source.is_null());
        let i = app.active_tab;
        let invalid = app.tabs[i].scene.add_entity(acadrust::EntityType::Surface(Surface::new(SurfaceKind::Generic)));
        let original = serde_json::to_value(app.tabs[i].scene.document.get_entity(source).unwrap()).unwrap();
        let before = app.tabs[i].history.undo_stack.len();
        let _ = app.apply_cmd_result(CmdResult::ThickenEntities { handles: vec![source], distance: 0.0 });
        assert_eq!(app.tabs[i].history.undo_stack.len(), before);
        let _ = app.apply_cmd_result(CmdResult::ThickenEntities { handles: vec![invalid, source], distance: 2.0 });
        assert_eq!(app.tabs[i].history.undo_stack.len(), before + 1);
        let result = app.tabs[i].scene.document.entities().find_map(|entity| {
            matches!(entity, acadrust::EntityType::Solid3D(_)).then_some(entity.common().handle)
        }).unwrap();
        assert!(app.tabs[i].scene.document.solid_history_operation(result).is_some());
        assert_eq!(serde_json::to_value(app.tabs[i].scene.document.get_entity(source).unwrap()).unwrap(), original);
        let expected = cadkernel::brep::analytic_mass_properties(&app.tabs[i].scene.solid_models[&result]).unwrap().volume;
        let bytes = crate::io::save_to_bytes(&app.tabs[i].scene.document, "dwg", app.tabs[i].scene.document.version).unwrap();
        let document = crate::io::load_bytes("thicken.dwg", bytes).unwrap();
        let mut restored = crate::scene::Scene::new();
        restored.document = document;
        restored.restore_solid_models(&[result]);
        let actual = cadkernel::brep::analytic_mass_properties(&restored.solid_models[&result]).unwrap().volume;
        assert!((expected - actual).abs() < 1e-8);
        app.undo_active_tab();
        assert!(app.tabs[i].scene.document.get_entity(result).is_none());
        assert!(app.tabs[i].scene.document.solid_history_operation(result).is_none());
        assert!(app.tabs[i].scene.document.get_entity(source).is_some());
        assert!(app.tabs[i].scene.document.get_entity(invalid).is_some());
        app.redo_active_tab();
        assert!(app.tabs[i].scene.document.get_entity(result).is_some());
        assert!(app.tabs[i].scene.document.solid_history_operation(result).is_some());
        assert_eq!(serde_json::to_value(app.tabs[i].scene.document.get_entity(source).unwrap()).unwrap(), original);
    }

    #[test]
    fn thicken_creates_a_solid_from_a_free_form_surface() {
        let mut app = OpenCADStudio::new_for_test();
        app.automation_op(r#"{"op":"new"}"#);
        let profile = NurbsCurve::interpolate(
            &[[0.0, 0.0], [0.7, 0.15], [1.3, -0.1], [2.0, 0.0]],
            None,
            None,
            Parameterization::Chord,
        )
        .unwrap();
        let body = cadkernel::brep::extrude_surface(
            Plane::XY,
            &[Curve::Nurbs(profile)],
            [0.0, 0.0, 2.0],
        )
        .unwrap();
        let source = app.add_surface_model(
            acadrust::EntityType::Surface(Surface::new(SurfaceKind::Generic)),
            body,
        );
        let i = app.active_tab;

        let _ = app.apply_cmd_result(CmdResult::ThickenEntities {
            handles: vec![source],
            distance: 0.15,
        });

        let solids = app.tabs[i]
            .scene
            .document
            .entities()
            .filter_map(|entity| {
                matches!(entity, acadrust::EntityType::Solid3D(_))
                    .then_some(entity.common().handle)
            })
            .collect::<Vec<_>>();
        assert_eq!(solids.len(), 1);
        let solid = &app.tabs[i].scene.solid_models[&solids[0]];
        assert!(solid.validate().is_empty());
        assert!(solid.edges.iter().all(|(_, edge)| edge.coedges.len() == 2));
        assert!(app.tabs[i]
            .scene
            .document
            .solid_history_operation(solids[0])
            .is_some());
        assert!(app.tabs[i].scene.document.get_entity(source).is_some());
    }
}