Match Smooth connected-endpoint workflow

src/app/command_driver.rs

@@ -849,6 +849,36 @@ impl OpenCADStudio {
     /// 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::AddParametricConstraint {
+            kind,
+            refs,
+            ..
+        } = &mut result
+        {
+            if *kind == crate::scene::parametric_constraints::ConstraintKind::Smooth
+                && refs.len() == 1
+            {
+                let source = refs[0];
+                let scope = self.tabs[i].current_parametric_scope();
+                let Some(resolved) = self.tabs[i]
+                    .scene
+                    .smooth_refs_from_connected_spline(scope, source.entity, source.marker)
+                else {
+                    self.tabs[i].snap_result = None;
+                    self.command_line
+                        .push_error("No valid constraint point found.");
+                    if let Some(prompt) = self.tabs[i]
+                        .active_cmd
+                        .as_ref()
+                        .map(|command| command.prompt())
+                    {
+                        self.command_line.push_info(&prompt);
+                    }
+                    return Task::none();
+                };
+                *refs = resolved;
+            }
+        }
         if let CmdResult::ReturnPoint(pt) = result {
             self.tabs[i].scene.clear_preview_wire();
             if let Some(mut suspended) = self.tabs[i].suspended_cmd.take() {

src/app/commands/draw.rs

@@ -1213,41 +1213,32 @@ impl OpenCADStudio {
                     let command = SmoothConstraintCommand::new();
                     self.command_line.push_info(&command.prompt());
                     self.tabs[i].active_cmd = Some(Box::new(command));
-                } else if handles.len() != 2 {
-                    self.tabs[i].scene.deselect_all();
-                    self.command_line.push_error(
-                        "Smooth requires an open spline first and a target curve second.",
-                    );
-                    let command = SmoothConstraintCommand::new();
-                    self.command_line.push_info(&command.prompt());
-                    self.tabs[i].active_cmd = Some(Box::new(command));
                 } else {
-                    let first = self.tabs[i].scene.document.get_entity(handles[0]);
-                    let second = self.tabs[i].scene.document.get_entity(handles[1]);
-                    let refs = first.zip(second).and_then(|(first, second)| {
-                        SmoothConstraintCommand::preselected_refs(
-                            (first, handles[0]),
-                            (second, handles[1]),
-                        )
-                    });
-                    let Some(refs) = refs else {
+                    let scope = self.tabs[i].current_parametric_scope();
+                    let refs = (handles.len() == 1)
+                        .then(|| {
+                            self.tabs[i]
+                                .scene
+                                .smooth_refs_from_connected_spline(scope, handles[0], None)
+                        })
+                        .flatten();
+                    if let Some(refs) = refs {
+                        use crate::command::CmdResult;
+                        use crate::scene::parametric_constraints::ConstraintKind;
+                        return Some(self.apply_cmd_result(CmdResult::AddParametricConstraint {
+                            kind: ConstraintKind::Smooth,
+                            refs,
+                            driving_param: None,
+                            label: "Smooth constraint",
+                        }));
+                    } else {
                         self.tabs[i].scene.deselect_all();
-                        self.command_line.push_error(
-                            "Smooth requires an open spline first and a line, arc, polyline segment or open spline second.",
-                        );
+                        self.command_line
+                            .push_error("No valid constraint point found.");
                         let command = SmoothConstraintCommand::new();
                         self.command_line.push_info(&command.prompt());
                         self.tabs[i].active_cmd = Some(Box::new(command));
-                        return None;
-                    };
-                    use crate::command::CmdResult;
-                    use crate::scene::parametric_constraints::ConstraintKind;
-                    return Some(self.apply_cmd_result(CmdResult::AddParametricConstraint {
-                        kind: ConstraintKind::Smooth,
-                        refs,
-                        driving_param: None,
-                        label: "Smooth constraint",
-                    }));
+                    }
                 }
             }