From f80e9f742c8aabef44ca9ed694b3841adf1e9aa5 Mon Sep 17 00:00:00 2001
From: ramox81 <184937705+ramox81@users.noreply.github.com>
Date: Fri, 11 Sep 2026 10:25:11 +0300
Subject: [PATCH] Reverse selected curves while preserving spline shape

---
 src/app/commands/draw.rs           | 20 +++++++++++++++++---
 src/modules/draw/modify/reverse.rs | 14 ++++++++------
 2 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/src/app/commands/draw.rs b/src/app/commands/draw.rs
index cf848ff7b..7c5ce76ce 100644
--- a/src/app/commands/draw.rs
+++ b/src/app/commands/draw.rs
@@ -596,9 +596,23 @@ impl OpenCADStudio {
 
             "REVERSE" => {
                 use crate::modules::draw::modify::reverse::ReverseCommand;
-                let new_cmd = ReverseCommand::new();
-                self.command_line.push_info(&new_cmd.prompt());
-                self.tabs[i].active_cmd = Some(Box::new(new_cmd));
+                if self.tabs[i].scene.selected.is_empty() {
+                    use crate::modules::draw::select::SelectObjectsCommand;
+                    let selection = SelectObjectsCommand::new("REVERSE");
+                    self.command_line.push_info(&selection.prompt());
+                    self.tabs[i].active_cmd = Some(Box::new(selection));
+                } else {
+                    let replacements = self.tabs[i].scene.selected_entities().into_iter()
+                        .filter(|(handle, _)| !self.tabs[i].scene.is_layer_locked(*handle))
+                        .filter_map(|(handle, entity)| ReverseCommand::reversed(entity)
+                            .map(|reversed| (handle, vec![reversed])))
+                        .collect::<Vec<_>>();
+                    if !replacements.is_empty() {
+                        return Some(self.apply_cmd_result(crate::command::CmdResult::ReplaceMany(
+                            replacements, Vec::new(),
+                        )));
+                    }
+                }
             }
 
             "MEASUREGEOM" => {
diff --git a/src/modules/draw/modify/reverse.rs b/src/modules/draw/modify/reverse.rs
index 3d7e3d51e..4e2cfdffd 100644
--- a/src/modules/draw/modify/reverse.rs
+++ b/src/modules/draw/modify/reverse.rs
@@ -54,7 +54,7 @@ impl ReverseCommand {
     }
 
     /// Build a reversed copy of `entity`, or `None` for an unsupported type.
-    fn reversed(entity: &EntityType) -> Option<EntityType> {
+    pub fn reversed(entity: &EntityType) -> Option<EntityType> {
         match entity {
             EntityType::Line(line) => {
                 let mut out = line.clone();
@@ -176,9 +176,8 @@ fn reverse_polyline2d(pl: &acadrust::entities::Polyline2D) -> acadrust::entities
     out
 }
 
-/// Reverse a Spline: flip control points and fit points, regenerate the
-/// clamped knot vector. Mirrors `splinedit::apply_spline_op`'s REVERSE branch.
-fn reverse_spline(sp: &Spline) -> Spline {
+/// Reverse stored coordinates in 3D and let the kernel mirror the knot domain.
+pub(super) fn reverse_spline(sp: &Spline) -> Spline {
     let mut out = sp.clone();
     out.control_points.reverse();
     out.fit_points.reverse();
@@ -186,8 +185,11 @@ fn reverse_spline(sp: &Spline) -> Spline {
     if out.weights.len() == out.control_points.len() {
         out.weights.reverse();
     }
-    out.knots =
-        Spline::generate_clamped_knots(out.degree as usize, out.control_points.len());
+    if let Some(curve) = super::spline_ops::spline_to_nurbs(sp) {
+        out.knots = curve.reversed().knots().to_vec();
+    }
+    out.begin_tangent = acadrust::types::Vector3::new(-sp.end_tangent.x, -sp.end_tangent.y, -sp.end_tangent.z);
+    out.end_tangent = acadrust::types::Vector3::new(-sp.begin_tangent.x, -sp.begin_tangent.y, -sp.begin_tangent.z);
     out
 }