From ec02e16c8196f08f5b7c63ca1cedd94a40de629c Mon Sep 17 00:00:00 2001
From: smoogipoo <smoogipoo@smgi.me>
Date: Fri, 22 Oct 2021 20:53:45 +0900
Subject: [PATCH] Add playlist item change event

---
 .../Online/Multiplayer/IMultiplayerClient.cs  |  6 ++
 .../Online/Multiplayer/MultiplayerClient.cs   | 62 +++++++++++++------
 2 files changed, 50 insertions(+), 18 deletions(-)

diff --git a/osu.Game/Online/Multiplayer/IMultiplayerClient.cs b/osu.Game/Online/Multiplayer/IMultiplayerClient.cs
index 3eafb31510..81979c146c 100644
--- a/osu.Game/Online/Multiplayer/IMultiplayerClient.cs
+++ b/osu.Game/Online/Multiplayer/IMultiplayerClient.cs
@@ -118,5 +118,11 @@ namespace osu.Game.Online.Multiplayer
         /// </summary>
         /// <param name="item">The removed item.</param>
         Task PlaylistItemRemoved(APIPlaylistItem item);
+
+        /// <summary>
+        /// Signals that an item has been changed in the playlist.
+        /// </summary>
+        /// <param name="item">The changed item.</param>
+        Task PlaylistItemChanged(APIPlaylistItem item);
     }
 }
diff --git a/osu.Game/Online/Multiplayer/MultiplayerClient.cs b/osu.Game/Online/Multiplayer/MultiplayerClient.cs
index 72ac13c2f2..1b321421e3 100644
--- a/osu.Game/Online/Multiplayer/MultiplayerClient.cs
+++ b/osu.Game/Online/Multiplayer/MultiplayerClient.cs
@@ -577,12 +577,7 @@ namespace osu.Game.Online.Multiplayer
             if (Room == null)
                 return;
 
-            var set = await GetOnlineBeatmapSet(item.BeatmapID).ConfigureAwait(false);
-
-            var beatmap = set.Beatmaps.Single(b => b.OnlineBeatmapID == item.BeatmapID);
-            beatmap.MD5Hash = item.BeatmapChecksum;
-
-            var ruleset = Rulesets.GetRuleset(item.RulesetID);
+            var playlistItem = await createPlaylistItem(item).ConfigureAwait(false);
 
             await scheduleAsync(() =>
             {
@@ -591,18 +586,6 @@ namespace osu.Game.Online.Multiplayer
 
                 Debug.Assert(APIRoom != null);
 
-                var playlistItem = new PlaylistItem
-                {
-                    ID = item.ID,
-                    Beatmap = { Value = beatmap },
-                    Ruleset = { Value = ruleset },
-                };
-
-                var rulesetInstance = ruleset.CreateInstance();
-
-                playlistItem.RequiredMods.AddRange(item.RequiredMods.Select(m => m.ToMod(rulesetInstance)));
-                playlistItem.AllowedMods.AddRange(item.AllowedMods.Select(m => m.ToMod(rulesetInstance)));
-
                 APIRoom.Playlist.Add(playlistItem);
                 RoomUpdated?.Invoke();
             }).ConfigureAwait(false);
@@ -625,6 +608,26 @@ namespace osu.Game.Online.Multiplayer
             });
         }
 
+        public async Task PlaylistItemChanged(APIPlaylistItem item)
+        {
+            if (Room == null)
+                return;
+
+            var playlistItem = await createPlaylistItem(item).ConfigureAwait(false);
+
+            await scheduleAsync(() =>
+            {
+                if (Room == null)
+                    return;
+
+                Debug.Assert(APIRoom != null);
+
+                int index = APIRoom.Playlist.Where(p => p.ID == item.ID).Select((_, i) => i).Single();
+                APIRoom.Playlist.RemoveAt(index);
+                APIRoom.Playlist.Insert(index, playlistItem);
+            }).ConfigureAwait(false);
+        }
+
         /// <summary>
         /// Populates the <see cref="User"/> for a given <see cref="MultiplayerRoomUser"/>.
         /// </summary>
@@ -663,6 +666,29 @@ namespace osu.Game.Online.Multiplayer
         /// <returns>The <see cref="BeatmapSetInfo"/> retrieval task.</returns>
         protected abstract Task<BeatmapSetInfo> GetOnlineBeatmapSet(int beatmapId, CancellationToken cancellationToken = default);
 
+        private async Task<PlaylistItem> createPlaylistItem(APIPlaylistItem item)
+        {
+            var set = await GetOnlineBeatmapSet(item.BeatmapID).ConfigureAwait(false);
+
+            var beatmap = set.Beatmaps.Single(b => b.OnlineBeatmapID == item.BeatmapID);
+            beatmap.MD5Hash = item.BeatmapChecksum;
+
+            var ruleset = Rulesets.GetRuleset(item.RulesetID);
+            var rulesetInstance = ruleset.CreateInstance();
+
+            var playlistItem = new PlaylistItem
+            {
+                ID = item.ID,
+                Beatmap = { Value = beatmap },
+                Ruleset = { Value = ruleset },
+            };
+
+            playlistItem.RequiredMods.AddRange(item.RequiredMods.Select(m => m.ToMod(rulesetInstance)));
+            playlistItem.AllowedMods.AddRange(item.AllowedMods.Select(m => m.ToMod(rulesetInstance)));
+
+            return playlistItem;
+        }
+
         /// <summary>
         /// For the provided user ID, update whether the user is included in <see cref="CurrentMatchPlayingUserIds"/>.
         /// </summary>