feat(clipboard): PASTESPEC pastes in a chosen format

PASTESPEC offers the formats on the clipboard: Objects and Block for
objects copied in the application (the PASTECLIP and PASTEBLOCK paths),
and Text for the system clipboard's text, placed as multi-line text in
the current text style with its lines as paragraphs.

Refs #645

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/modules/draw/clipboard/mod.rs

@@ -2,3 +2,4 @@ pub mod copy_base;
 pub mod copy_clip;
 pub mod cut;
 pub mod paste;
+pub mod pastespec;

src/modules/draw/clipboard/pastespec.rs

@@ -0,0 +1,136 @@
+// PASTESPEC — paste the clipboard in a chosen format: the copied objects, the
+// copied objects as a block, or the system clipboard's text as multi-line text.
+
+use crate::t;
+use codec::entities::mtext::AttachmentPoint;
+use codec::entities::MText;
+use codec::types::Vector3;
+use codec::EntityType;
+use glam::DVec3;
+
+use crate::command::{CadCommand, CmdOption, CmdResult, WorkingPlane};
+
+pub struct PasteSpecCommand {
+    /// Objects copied inside the application are waiting on the clipboard.
+    objects: bool,
+    /// The system clipboard's text, already escaped for MTEXT.
+    text: Option<String>,
+    style: String,
+    height: f64,
+    placing_text: bool,
+    plane: WorkingPlane,
+}
+
+impl PasteSpecCommand {
+    pub fn new(objects: bool, text: Option<&str>, style: String, height: f64) -> Self {
+        Self {
+            objects,
+            text: text.map(mtext_value),
+            style,
+            height,
+            placing_text: false,
+            plane: WorkingPlane::default(),
+        }
+    }
+}
+
+/// Plain text as an MTEXT value: control characters escaped, lines as
+/// paragraphs.
+fn mtext_value(text: &str) -> String {
+    text.trim_end_matches(['\r', '\n'])
+        .replace('\\', "\\\\")
+        .replace('{', "\\{")
+        .replace('}', "\\}")
+        .replace("\r\n", "\\P")
+        .replace(['\r', '\n'], "\\P")
+}
+
+impl CadCommand for PasteSpecCommand {
+    fn name(&self) -> &'static str {
+        "PASTESPEC"
+    }
+
+    fn set_working_plane(&mut self, plane: WorkingPlane) {
+        self.plane = plane;
+    }
+
+    fn prompt(&self) -> String {
+        if self.placing_text {
+            t!("PASTESPEC  Specify insertion point:").into_owned()
+        } else {
+            t!("PASTESPEC  Paste as [Objects/Block/Text]:").into_owned()
+        }
+    }
+
+    fn options(&self) -> Vec<CmdOption> {
+        if self.placing_text {
+            return Vec::new();
+        }
+        let mut options = Vec::new();
+        if self.objects {
+            options.push(CmdOption::new("Objects", "O"));
+            options.push(CmdOption::new("Block", "B"));
+        }
+        if self.text.is_some() {
+            options.push(CmdOption::new("Text", "T"));
+        }
+        options
+    }
+
+    fn wants_text_input(&self) -> bool {
+        !self.placing_text
+    }
+
+    fn on_text_input(&mut self, text: &str) -> Option<CmdResult> {
+        if self.placing_text {
+            return None;
+        }
+        match text.trim().trim_start_matches('_').to_ascii_uppercase().as_str() {
+            "O" | "OBJECTS" if self.objects => Some(CmdResult::Dispatch("PASTECLIP".into())),
+            "B" | "BLOCK" if self.objects => Some(CmdResult::Dispatch("PASTEBLOCK".into())),
+            "T" | "TEXT" if self.text.is_some() => {
+                self.placing_text = true;
+                Some(CmdResult::NeedPoint)
+            }
+            _ => None,
+        }
+    }
+
+    fn on_point(&mut self, pt: DVec3) -> CmdResult {
+        let Some(value) = self.text.clone().filter(|_| self.placing_text) else {
+            return CmdResult::NeedPoint;
+        };
+        let p = self.plane.to_local(pt);
+        let mut mtext = MText::new();
+        mtext.value = value;
+        mtext.insertion_point = Vector3::new(p.x, p.y, p.z);
+        mtext.height = self.height;
+        mtext.style = self.style.clone();
+        mtext.attachment_point = AttachmentPoint::TopLeft;
+        mtext.rectangle_width = 0.0;
+        CmdResult::CommitAndExit(self.plane.place_entity(EntityType::MText(mtext)))
+    }
+
+    fn on_enter(&mut self) -> CmdResult {
+        if self.placing_text {
+            return CmdResult::NeedPoint;
+        }
+        // Enter takes the first format offered.
+        let first = self.options().first().map(|o| o.keyword.clone());
+        first
+            .and_then(|keyword| self.on_text_input(&keyword))
+            .unwrap_or(CmdResult::Cancel)
+    }
+}
+
+inventory::submit!(crate::command::CommandRegistration { names: &["PASTESPEC"] });
+
+#[cfg(test)]
+mod tests {
+    use super::mtext_value;
+
+    #[test]
+    fn plain_text_becomes_escaped_paragraphs() {
+        assert_eq!(mtext_value("a{b}\\c\r\nline 2\n"), "a\\{b\\}\\\\c\\Pline 2");
+    }
+}