From 2dbfdc3d2c0276e431b4b45bc4dabbb4f480b5b0 Mon Sep 17 00:00:00 2001
From: Dan Balasescu <smoogipoo@smgi.me>
Date: Mon, 20 Oct 2025 17:02:35 +0900
Subject: [PATCH] Preview next song in quick play

---
 .../Matchmaking/Match/ScreenMatchmaking.cs    | 60 ++++++++++++++++++-
 1 file changed, 59 insertions(+), 1 deletion(-)

diff --git a/osu.Game/Screens/OnlinePlay/Matchmaking/Match/ScreenMatchmaking.cs b/osu.Game/Screens/OnlinePlay/Matchmaking/Match/ScreenMatchmaking.cs
index 590d84f310..a40510aab5 100644
--- a/osu.Game/Screens/OnlinePlay/Matchmaking/Match/ScreenMatchmaking.cs
+++ b/osu.Game/Screens/OnlinePlay/Matchmaking/Match/ScreenMatchmaking.cs
@@ -16,6 +16,7 @@ using osu.Framework.Graphics.Shapes;
 using osu.Framework.Input.Events;
 using osu.Framework.Logging;
 using osu.Framework.Screens;
+using osu.Game.Audio;
 using osu.Game.Beatmaps;
 using osu.Game.Database;
 using osu.Game.Graphics.Cursor;
@@ -37,7 +38,7 @@ namespace osu.Game.Screens.OnlinePlay.Matchmaking.Match
     /// <summary>
     /// The main matchmaking screen which houses a custom <see cref="ScreenStack"/> through the life cycle of a single session.
     /// </summary>
-    public partial class ScreenMatchmaking : OsuScreen
+    public partial class ScreenMatchmaking : OsuScreen, IPreviewTrackOwner
     {
         /// <summary>
         /// Padding between rows of the content.
@@ -74,6 +75,12 @@ namespace osu.Game.Screens.OnlinePlay.Matchmaking.Match
         [Resolved]
         private AudioManager audio { get; set; } = null!;
 
+        [Resolved]
+        private PreviewTrackManager previewTrackManager { get; set; } = null!;
+
+        [Resolved]
+        private MusicController music { get; set; } = null!;
+
         private readonly MultiplayerRoom room;
 
         private Sample? sampleStart;
@@ -308,6 +315,18 @@ namespace osu.Game.Screens.OnlinePlay.Matchmaking.Match
             return false;
         }
 
+        public override void OnEntering(ScreenTransitionEvent e)
+        {
+            base.OnEntering(e);
+            beginHandlingTrack();
+        }
+
+        public override void OnSuspending(ScreenTransitionEvent e)
+        {
+            onLeaving();
+            base.OnSuspending(e);
+        }
+
         private bool exitConfirmed;
 
         public override bool OnExiting(ScreenExitEvent e)
@@ -320,6 +339,7 @@ namespace osu.Game.Screens.OnlinePlay.Matchmaking.Match
                     return true;
                 }
 
+                onLeaving();
                 client.LeaveRoom().FireAndForget();
                 return false;
             }
@@ -342,6 +362,7 @@ namespace osu.Game.Screens.OnlinePlay.Matchmaking.Match
         public override void OnResuming(ScreenTransitionEvent e)
         {
             base.OnResuming(e);
+            beginHandlingTrack();
 
             if (e.Last is not MultiplayerPlayerLoader playerLoader)
                 return;
@@ -355,6 +376,43 @@ namespace osu.Game.Screens.OnlinePlay.Matchmaking.Match
             client.ChangeState(MultiplayerUserState.Idle);
         }
 
+        private void onLeaving()
+        {
+            endHandlingTrack();
+        }
+
+        /// <summary>
+        /// Handles changes in the track to keep it looping while active.
+        /// </summary>
+        private void beginHandlingTrack()
+        {
+            Beatmap.BindValueChanged(applyLoopingToTrack, true);
+        }
+
+        /// <summary>
+        /// Stops looping the current track and stops handling further changes to the track.
+        /// </summary>
+        private void endHandlingTrack()
+        {
+            Beatmap.ValueChanged -= applyLoopingToTrack;
+            Beatmap.Value.Track.Looping = false;
+
+            previewTrackManager.StopAnyPlaying(this);
+        }
+
+        /// <summary>
+        /// Invoked on changes to the beatmap to loop the track. See: <see cref="beginHandlingTrack"/>.
+        /// </summary>
+        /// <param name="beatmap">The beatmap change event.</param>
+        private void applyLoopingToTrack(ValueChangedEvent<WorkingBeatmap> beatmap)
+        {
+            if (!this.IsCurrentScreen())
+                return;
+
+            beatmap.NewValue.PrepareTrackForPreview(true);
+            music.EnsurePlayingSomething();
+        }
+
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);