From cc01b9e639f3542fc5ed6633aa6f75d765c0e50e Mon Sep 17 00:00:00 2001
From: ekrctb <ekrctb@gmail.com>
Date: Thu, 22 Jul 2021 16:14:43 +0900
Subject: [PATCH] Extract `SliderPath` reverse logic to be used in other
 rulesets

---
 .../Edit/OsuSelectionHandler.cs               | 28 +----------
 .../Rulesets/Objects/SliderPathExtensions.cs  | 47 +++++++++++++++++++
 2 files changed, 49 insertions(+), 26 deletions(-)
 create mode 100644 osu.Game/Rulesets/Objects/SliderPathExtensions.cs

diff --git a/osu.Game.Rulesets.Osu/Edit/OsuSelectionHandler.cs b/osu.Game.Rulesets.Osu/Edit/OsuSelectionHandler.cs
index c2c2226af0..358a44e0e6 100644
--- a/osu.Game.Rulesets.Osu/Edit/OsuSelectionHandler.cs
+++ b/osu.Game.Rulesets.Osu/Edit/OsuSelectionHandler.cs
@@ -76,32 +76,8 @@ namespace osu.Game.Rulesets.Osu.Edit
 
                 if (h is Slider slider)
                 {
-                    var points = slider.Path.ControlPoints.ToArray();
-                    Vector2 endPos = points.Last().Position.Value;
-
-                    slider.Path.ControlPoints.Clear();
-
-                    slider.Position += endPos;
-
-                    PathType? lastType = null;
-
-                    for (var i = 0; i < points.Length; i++)
-                    {
-                        var p = points[i];
-                        p.Position.Value -= endPos;
-
-                        // propagate types forwards to last null type
-                        if (i == points.Length - 1)
-                            p.Type.Value = lastType;
-                        else if (p.Type.Value != null)
-                        {
-                            var newType = p.Type.Value;
-                            p.Type.Value = lastType;
-                            lastType = newType;
-                        }
-
-                        slider.Path.ControlPoints.Insert(0, p);
-                    }
+                    slider.Path.Reverse(out Vector2 offset);
+                    slider.Position += offset;
                 }
             }
 
diff --git a/osu.Game/Rulesets/Objects/SliderPathExtensions.cs b/osu.Game/Rulesets/Objects/SliderPathExtensions.cs
new file mode 100644
index 0000000000..1438c2f128
--- /dev/null
+++ b/osu.Game/Rulesets/Objects/SliderPathExtensions.cs
@@ -0,0 +1,47 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.Linq;
+using osu.Game.Rulesets.Objects.Types;
+using osuTK;
+
+#nullable enable
+
+namespace osu.Game.Rulesets.Objects
+{
+    public static class SliderPathExtensions
+    {
+        /// <summary>
+        /// Reverse the direction of this path.
+        /// </summary>
+        /// <param name="sliderPath">The <see cref="SliderPath"/>.</param>
+        /// <param name="positionalOffset">The positional offset of the resulting path. It should be added to the start position of this path.</param>
+        public static void Reverse(this SliderPath sliderPath, out Vector2 positionalOffset)
+        {
+            var points = sliderPath.ControlPoints.ToArray();
+            positionalOffset = points.Last().Position.Value;
+
+            sliderPath.ControlPoints.Clear();
+
+            PathType? lastType = null;
+
+            for (var i = 0; i < points.Length; i++)
+            {
+                var p = points[i];
+                p.Position.Value -= positionalOffset;
+
+                // propagate types forwards to last null type
+                if (i == points.Length - 1)
+                    p.Type.Value = lastType;
+                else if (p.Type.Value != null)
+                {
+                    var newType = p.Type.Value;
+                    p.Type.Value = lastType;
+                    lastType = newType;
+                }
+
+                sliderPath.ControlPoints.Insert(0, p);
+            }
+        }
+    }
+}