Feature history on the left side, with contiguous folders (#449)

The feature history can sit in a panel on the left, with folders that hold one unbroken run of features, drag and drop as one undo step, and a resizable divider. Timeline folders save under format 17.

crates/ui-egui/src/timeline.rs

@@ -7,7 +7,7 @@ use solidcraft_engine::doc::FeatureKind;
 use crate::theme::Tokens;
 use crate::{SolveApp, icons};
 
-fn icon_of(k: &FeatureKind) -> &'static str {
+pub(crate) fn icon_of(k: &FeatureKind) -> &'static str {
     match k {
         FeatureKind::Sketch { .. } => "sketch",
         FeatureKind::Extrude { .. } => "extrude",
@@ -37,8 +37,7 @@ fn icon_of(k: &FeatureKind) -> &'static str {
     }
 }
 
-/// What a drag in the timeline is moving.
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 enum Drag {
     Marker,
     Feature(u64),
@@ -57,16 +56,24 @@ fn slot_at(xs: &[f32], end: f32, x: f32) -> usize {
 }
 
 /// Ask before deleting a feature others depend on; delete right away otherwise.
-fn delete_feature(app: &mut SolveApp, id: u64) {
-    let deps = app.session.execute("timeline.dependents", &json!({ "feature": id })).unwrap_or_default();
-    let list = |k: &str| -> Vec<String> {
-        deps.get(k).and_then(|v| v.as_array()).into_iter().flatten().filter_map(|x| x.as_str().map(String::from)).collect()
-    };
-    let (with, fail) = (list("deleted_with_it"), list("would_fail"));
+pub(crate) fn delete_feature(app: &mut SolveApp, id: u64) {
+    delete_features(app, vec![id]);
+}
+
+pub(crate) fn delete_features(app: &mut SolveApp, ids: Vec<u64>) {
+    let mut with = std::collections::BTreeSet::new();
+    let mut fail = std::collections::BTreeSet::new();
+    for id in &ids {
+        let deps = app.session.execute("timeline.dependents", &json!({ "feature": id })).unwrap_or_default();
+        for (key, output) in [("deleted_with_it", &mut with), ("would_fail", &mut fail)] {
+            output
+                .extend(deps.get(key).and_then(|value| value.as_array()).into_iter().flatten().filter_map(|value| value.as_str().map(String::from)));
+        }
+    }
     if with.is_empty() && fail.is_empty() {
-        let _ = app.run("timeline.delete", json!({ "features": [id.to_string()] }));
+        let _ = app.run("timeline.delete", json!({ "features": ids }));
     } else {
-        app.dialog = Some(crate::dialogs::Dialog::confirm_delete(id, with, fail));
+        app.dialog = Some(crate::dialogs::Dialog::confirm_delete_many(ids, with.into_iter().collect(), fail.into_iter().collect()));
     }
 }
 
@@ -281,12 +288,12 @@ pub fn timeline(app: &mut SolveApp, ui: &mut egui::Ui) {
                 // The scroll range follows the drawn content (the buttons don't take layout space themselves).
                 ui.allocate_exact_size(vec2((content_end - origin).max(0.0), r.height()), Sense::hover());
                 // Drag feedback, and the drop.
-                if let (Some(dg), Some(pp)) = (drag, pointer) {
+                if let (Some(dg), Some(pp)) = (drag.as_ref(), pointer) {
                     let slot = slot_at(&xs, end, pp.x);
                     let sx = xs.get(slot).copied().unwrap_or(end) - 4.0;
                     p.line_segment(
                         [pos2(sx, r.top() + 3.0), pos2(sx, r.bottom() - 3.0)],
-                        Stroke::new(2.0, if dg == Drag::Marker { t.accent } else { t.sketch_accent }),
+                        Stroke::new(2.0, if matches!(dg, Drag::Marker) { t.accent } else { t.sketch_accent }),
                     );
                 }
                 let released = ui.input(|i| i.pointer.any_released());
@@ -312,7 +319,7 @@ pub fn timeline(app: &mut SolveApp, ui: &mut egui::Ui) {
                 }
                 ui.data_mut(|d| match drag {
                     Some(dg) => {
-                        d.insert_temp(drag_id, dg);
+                        d.insert_temp(drag_id, dg.clone());
                     }
                     None => d.remove::<Drag>(drag_id),
                 });
@@ -334,7 +341,7 @@ fn find_in_browser(app: &mut SolveApp, id: u64) {
 }
 
 /// Transport buttons drawn as shapes (the UI font has no media glyphs).
-fn transport_glyph(p: &egui::Painter, c: egui::Pos2, what: &str, col: Color32) {
+pub(crate) fn transport_glyph(p: &egui::Painter, c: egui::Pos2, what: &str, col: Color32) {
     let tri = |dir: f32, dx: f32| {
         let pts = vec![pos2(c.x + dx - 4.0 * dir, c.y - 5.0), pos2(c.x + dx + 4.0 * dir, c.y), pos2(c.x + dx - 4.0 * dir, c.y + 5.0)];
         p.add(egui::Shape::convex_polygon(pts, col, Stroke::NONE));