From 694cfd0e259d2e5357a5692b4e05c8e680ddb49c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Dach?= <dach.bartlomiej@gmail.com>
Date: Tue, 11 Jun 2024 09:15:14 +0200
Subject: [PATCH] Expose singular coarse-grained change event on
 `ControlPointInfo`

---
 .../Beatmaps/ControlPoints/ControlPointGroup.cs    |  5 +++++
 .../Beatmaps/ControlPoints/ControlPointInfo.cs     | 14 ++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/osu.Game/Beatmaps/ControlPoints/ControlPointGroup.cs b/osu.Game/Beatmaps/ControlPoints/ControlPointGroup.cs
index 1f34f3777d..c9c87dc85d 100644
--- a/osu.Game/Beatmaps/ControlPoints/ControlPointGroup.cs
+++ b/osu.Game/Beatmaps/ControlPoints/ControlPointGroup.cs
@@ -10,8 +10,11 @@ namespace osu.Game.Beatmaps.ControlPoints
     public class ControlPointGroup : IComparable<ControlPointGroup>, IEquatable<ControlPointGroup>
     {
         public event Action<ControlPoint>? ItemAdded;
+        public event Action<ControlPoint>? ItemChanged;
         public event Action<ControlPoint>? ItemRemoved;
 
+        private void raiseItemChanged(ControlPoint controlPoint) => ItemChanged?.Invoke(controlPoint);
+
         /// <summary>
         /// The time at which the control point takes effect.
         /// </summary>
@@ -39,12 +42,14 @@ public void Add(ControlPoint point)
 
             controlPoints.Add(point);
             ItemAdded?.Invoke(point);
+            point.Changed += raiseItemChanged;
         }
 
         public void Remove(ControlPoint point)
         {
             controlPoints.Remove(point);
             ItemRemoved?.Invoke(point);
+            point.Changed -= raiseItemChanged;
         }
 
         public sealed override bool Equals(object? obj)
diff --git a/osu.Game/Beatmaps/ControlPoints/ControlPointInfo.cs b/osu.Game/Beatmaps/ControlPoints/ControlPointInfo.cs
index 1a15db98e4..cb7515b66c 100644
--- a/osu.Game/Beatmaps/ControlPoints/ControlPointInfo.cs
+++ b/osu.Game/Beatmaps/ControlPoints/ControlPointInfo.cs
@@ -19,6 +19,14 @@ namespace osu.Game.Beatmaps.ControlPoints
     [Serializable]
     public class ControlPointInfo : IDeepCloneable<ControlPointInfo>
     {
+        /// <summary>
+        /// Invoked on any change to the set of control points.
+        /// </summary>
+        [CanBeNull]
+        public event Action ControlPointsChanged;
+
+        private void raiseControlPointsChanged([CanBeNull] ControlPoint _ = null) => ControlPointsChanged?.Invoke();
+
         /// <summary>
         /// All control points grouped by time.
         /// </summary>
@@ -116,6 +124,7 @@ public ControlPointGroup GroupAt(double time, bool addIfNotExisting = false)
             if (addIfNotExisting)
             {
                 newGroup.ItemAdded += GroupItemAdded;
+                newGroup.ItemChanged += raiseControlPointsChanged;
                 newGroup.ItemRemoved += GroupItemRemoved;
 
                 groups.Insert(~i, newGroup);
@@ -131,6 +140,7 @@ public void RemoveGroup(ControlPointGroup group)
                 group.Remove(item);
 
             group.ItemAdded -= GroupItemAdded;
+            group.ItemChanged -= raiseControlPointsChanged;
             group.ItemRemoved -= GroupItemRemoved;
 
             groups.Remove(group);
@@ -287,6 +297,8 @@ protected virtual void GroupItemAdded(ControlPoint controlPoint)
                 default:
                     throw new ArgumentException($"A control point of unexpected type {controlPoint.GetType()} was added to this {nameof(ControlPointInfo)}");
             }
+
+            raiseControlPointsChanged();
         }
 
         protected virtual void GroupItemRemoved(ControlPoint controlPoint)
@@ -301,6 +313,8 @@ protected virtual void GroupItemRemoved(ControlPoint controlPoint)
                     effectPoints.Remove(typed);
                     break;
             }
+
+            raiseControlPointsChanged();
         }
 
         public ControlPointInfo DeepClone()