Merge remote-tracking branch 'refs/remotes/ppy/master' into sidebar

osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/Components/PathControlPointVisualiser.cs

@@ -243,7 +243,7 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components
             int totalCount = Pieces.Count(p => p.IsSelected.Value);
             int countOfState = Pieces.Where(p => p.IsSelected.Value).Count(p => p.ControlPoint.Type.Value == type);
 
-            var item = new PathTypeMenuItem(type, () =>
+            var item = new TernaryStateRadioMenuItem(type == null ? "Inherit" : type.ToString().Humanize(), MenuItemType.Standard, _ =>
             {
                 foreach (var p in Pieces.Where(p => p.IsSelected.Value))
                     updatePathType(p, type);
@@ -258,15 +258,5 @@ namespace osu.Game.Rulesets.Osu.Edit.Blueprints.Sliders.Components
 
             return item;
         }
-
-        private class PathTypeMenuItem : TernaryStateMenuItem
-        {
-            public PathTypeMenuItem(PathType? type, Action action)
-                : base(type == null ? "Inherit" : type.ToString().Humanize(), changeState, MenuItemType.Standard, _ => action?.Invoke())
-            {
-            }
-
-            private static TernaryState changeState(TernaryState state) => TernaryState.True;
-        }
     }
 }

osu.Game.Rulesets.Taiko/Edit/TaikoSelectionHandler.cs

@@ -76,10 +76,10 @@ namespace osu.Game.Rulesets.Taiko.Edit
         protected override IEnumerable<MenuItem> GetContextMenuItemsForSelection(IEnumerable<SelectionBlueprint<HitObject>> selection)
         {
             if (selection.All(s => s.Item is Hit))
-                yield return new TernaryStateMenuItem("Rim") { State = { BindTarget = selectionRimState } };
+                yield return new TernaryStateToggleMenuItem("Rim") { State = { BindTarget = selectionRimState } };
 
             if (selection.All(s => s.Item is TaikoHitObject))
-                yield return new TernaryStateMenuItem("Strong") { State = { BindTarget = selectionStrongState } };
+                yield return new TernaryStateToggleMenuItem("Strong") { State = { BindTarget = selectionStrongState } };
 
             foreach (var item in base.GetContextMenuItemsForSelection(selection))
                 yield return item;

osu.Game.Tests/Visual/Gameplay/TestSceneHitErrorMeter.cs

@@ -1,6 +1,9 @@
 // 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;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
@@ -11,29 +14,35 @@ using osu.Game.Graphics.Sprites;
 using osu.Game.Rulesets.Catch.Scoring;
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Mania.Scoring;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Rulesets.Objects;
+using osu.Game.Rulesets.Osu;
 using osu.Game.Rulesets.Osu.Objects;
 using osu.Game.Rulesets.Osu.Scoring;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Rulesets.Taiko.Scoring;
+using osu.Game.Rulesets.UI;
+using osu.Game.Scoring;
 using osu.Game.Screens.Play.HUD.HitErrorMeters;
 
 namespace osu.Game.Tests.Visual.Gameplay
 {
     public class TestSceneHitErrorMeter : OsuTestScene
     {
-        private HitWindows hitWindows;
-
         [Cached]
         private ScoreProcessor scoreProcessor = new ScoreProcessor();
 
+        [Cached(typeof(DrawableRuleset))]
+        private TestDrawableRuleset drawableRuleset = new TestDrawableRuleset();
+
         public TestSceneHitErrorMeter()
         {
             recreateDisplay(new OsuHitWindows(), 5);
 
             AddRepeatStep("New random judgement", () => newJudgement(), 40);
 
-            AddRepeatStep("New max negative", () => newJudgement(-hitWindows.WindowFor(HitResult.Meh)), 20);
+            AddRepeatStep("New max negative", () => newJudgement(-drawableRuleset.HitWindows.WindowFor(HitResult.Meh)), 20);
-            AddRepeatStep("New max positive", () => newJudgement(hitWindows.WindowFor(HitResult.Meh)), 20);
+            AddRepeatStep("New max positive", () => newJudgement(drawableRuleset.HitWindows.WindowFor(HitResult.Meh)), 20);
             AddStep("New fixed judgement (50ms)", () => newJudgement(50));
 
             AddStep("Judgement barrage", () =>
@@ -83,10 +92,10 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         private void recreateDisplay(HitWindows hitWindows, float overallDifficulty)
         {
-            this.hitWindows = hitWindows;
-
             hitWindows?.SetDifficulty(overallDifficulty);
 
+            drawableRuleset.HitWindows = hitWindows;
+
             Clear();
 
             Add(new FillFlowContainer
@@ -103,40 +112,40 @@ namespace osu.Game.Tests.Visual.Gameplay
                 }
             });
 
-            Add(new BarHitErrorMeter(hitWindows, true)
+            Add(new BarHitErrorMeter
             {
                 Anchor = Anchor.CentreRight,
                 Origin = Anchor.CentreRight,
             });
 
-            Add(new BarHitErrorMeter(hitWindows, false)
+            Add(new BarHitErrorMeter
             {
                 Anchor = Anchor.CentreLeft,
                 Origin = Anchor.CentreLeft,
             });
 
-            Add(new BarHitErrorMeter(hitWindows, true)
+            Add(new BarHitErrorMeter
             {
                 Anchor = Anchor.BottomCentre,
                 Origin = Anchor.CentreLeft,
                 Rotation = 270,
             });
 
-            Add(new ColourHitErrorMeter(hitWindows)
+            Add(new ColourHitErrorMeter
             {
                 Anchor = Anchor.CentreRight,
                 Origin = Anchor.CentreRight,
                 Margin = new MarginPadding { Right = 50 }
             });
 
-            Add(new ColourHitErrorMeter(hitWindows)
+            Add(new ColourHitErrorMeter
             {
                 Anchor = Anchor.CentreLeft,
                 Origin = Anchor.CentreLeft,
                 Margin = new MarginPadding { Left = 50 }
             });
 
-            Add(new ColourHitErrorMeter(hitWindows)
+            Add(new ColourHitErrorMeter
             {
                 Anchor = Anchor.BottomCentre,
                 Origin = Anchor.CentreLeft,
@@ -147,11 +156,47 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         private void newJudgement(double offset = 0)
         {
-            scoreProcessor.ApplyResult(new JudgementResult(new HitCircle { HitWindows = hitWindows }, new Judgement())
+            scoreProcessor.ApplyResult(new JudgementResult(new HitCircle { HitWindows = drawableRuleset.HitWindows }, new Judgement())
             {
                 TimeOffset = offset == 0 ? RNG.Next(-150, 150) : offset,
                 Type = HitResult.Perfect,
             });
         }
+
+        [SuppressMessage("ReSharper", "UnassignedGetOnlyAutoProperty")]
+        private class TestDrawableRuleset : DrawableRuleset
+        {
+            public HitWindows HitWindows;
+
+            public override IEnumerable<HitObject> Objects => new[] { new HitCircle { HitWindows = HitWindows } };
+
+            public override event Action<JudgementResult> NewResult;
+            public override event Action<JudgementResult> RevertResult;
+
+            public override Playfield Playfield { get; }
+            public override Container Overlays { get; }
+            public override Container FrameStableComponents { get; }
+            public override IFrameStableClock FrameStableClock { get; }
+            public override IReadOnlyList<Mod> Mods { get; }
+
+            public override double GameplayStartTime { get; }
+            public override GameplayCursorContainer Cursor { get; }
+
+            public TestDrawableRuleset()
+                : base(new OsuRuleset())
+            {
+                // won't compile without this.
+                NewResult?.Invoke(null);
+                RevertResult?.Invoke(null);
+            }
+
+            public override void SetReplayScore(Score replayScore) => throw new NotImplementedException();
+
+            public override void SetRecordTarget(Score score) => throw new NotImplementedException();
+
+            public override void RequestResume(Action continueResume) => throw new NotImplementedException();
+
+            public override void CancelResume() => throw new NotImplementedException();
+        }
     }
 }

osu.Game.Tests/Visual/Gameplay/TestSceneSpectator.cs

@@ -27,8 +27,8 @@ namespace osu.Game.Tests.Visual.Gameplay
     {
         private readonly User streamingUser = new User { Id = MultiplayerTestScene.PLAYER_1_ID, Username = "Test user" };
 
-        [Cached(typeof(SpectatorStreamingClient))]
+        [Cached(typeof(SpectatorClient))]
-        private TestSpectatorStreamingClient testSpectatorStreamingClient = new TestSpectatorStreamingClient();
+        private TestSpectatorClient testSpectatorClient = new TestSpectatorClient();
 
         [Cached(typeof(UserLookupCache))]
         private UserLookupCache lookupCache = new TestUserLookupCache();
@@ -61,8 +61,8 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             AddStep("add streaming client", () =>
             {
-                Remove(testSpectatorStreamingClient);
+                Remove(testSpectatorClient);
-                Add(testSpectatorStreamingClient);
+                Add(testSpectatorClient);
             });
 
             finish();
@@ -212,9 +212,9 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         private void waitForPlayer() => AddUntilStep("wait for player", () => Stack.CurrentScreen is Player);
 
-        private void start(int? beatmapId = null) => AddStep("start play", () => testSpectatorStreamingClient.StartPlay(streamingUser.Id, beatmapId ?? importedBeatmapId));
+        private void start(int? beatmapId = null) => AddStep("start play", () => testSpectatorClient.StartPlay(streamingUser.Id, beatmapId ?? importedBeatmapId));
 
-        private void finish(int? beatmapId = null) => AddStep("end play", () => testSpectatorStreamingClient.EndPlay(streamingUser.Id, beatmapId ?? importedBeatmapId));
+        private void finish() => AddStep("end play", () => testSpectatorClient.EndPlay(streamingUser.Id));
 
         private void checkPaused(bool state) =>
             AddUntilStep($"game is {(state ? "paused" : "playing")}", () => player.ChildrenOfType<DrawableRuleset>().First().IsPaused.Value == state);
@@ -223,7 +223,7 @@ namespace osu.Game.Tests.Visual.Gameplay
         {
             AddStep("send frames", () =>
             {
-                testSpectatorStreamingClient.SendFrames(streamingUser.Id, nextFrame, count);
+                testSpectatorClient.SendFrames(streamingUser.Id, nextFrame, count);
                 nextFrame += count;
             });
         }

osu.Game.Tests/Visual/Gameplay/TestSceneSpectatorPlayback.cs

@@ -59,7 +59,7 @@ namespace osu.Game.Tests.Visual.Gameplay
         private IAPIProvider api { get; set; }
 
         [Resolved]
-        private SpectatorStreamingClient streamingClient { get; set; }
+        private SpectatorClient spectatorClient { get; set; }
 
         [Cached]
         private GameplayBeatmap gameplayBeatmap = new GameplayBeatmap(new Beatmap());
@@ -69,7 +69,7 @@ namespace osu.Game.Tests.Visual.Gameplay
         {
             replay = new Replay();
 
-            users.BindTo(streamingClient.PlayingUsers);
+            users.BindTo(spectatorClient.PlayingUsers);
             users.BindCollectionChanged((obj, args) =>
             {
                 switch (args.Action)
@@ -80,7 +80,7 @@ namespace osu.Game.Tests.Visual.Gameplay
                         foreach (int user in args.NewItems)
                         {
                             if (user == api.LocalUser.Value.Id)
-                                streamingClient.WatchUser(user);
+                                spectatorClient.WatchUser(user);
                         }
 
                         break;
@@ -91,14 +91,14 @@ namespace osu.Game.Tests.Visual.Gameplay
                         foreach (int user in args.OldItems)
                         {
                             if (user == api.LocalUser.Value.Id)
-                                streamingClient.StopWatchingUser(user);
+                                spectatorClient.StopWatchingUser(user);
                         }
 
                         break;
                 }
             }, true);
 
-            streamingClient.OnNewFrames += onNewFrames;
+            spectatorClient.OnNewFrames += onNewFrames;
 
             Add(new GridContainer
             {
@@ -189,7 +189,7 @@ namespace osu.Game.Tests.Visual.Gameplay
         {
         }
 
-        private double latency = SpectatorStreamingClient.TIME_BETWEEN_SENDS;
+        private double latency = SpectatorClient.TIME_BETWEEN_SENDS;
 
         protected override void Update()
         {
@@ -233,7 +233,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             AddStep("stop recorder", () =>
             {
                 recorder.Expire();
-                streamingClient.OnNewFrames -= onNewFrames;
+                spectatorClient.OnNewFrames -= onNewFrames;
             });
         }
 

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorLeaderboard.cs

@@ -23,8 +23,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public class TestSceneMultiSpectatorLeaderboard : MultiplayerTestScene
     {
-        [Cached(typeof(SpectatorStreamingClient))]
+        [Cached(typeof(SpectatorClient))]
-        private TestSpectatorStreamingClient streamingClient = new TestSpectatorStreamingClient();
+        private TestSpectatorClient spectatorClient = new TestSpectatorClient();
 
         [Cached(typeof(UserLookupCache))]
         private UserLookupCache lookupCache = new TestUserLookupCache();
@@ -42,7 +42,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             base.Content.AddRange(new Drawable[]
             {
-                streamingClient,
+                spectatorClient,
                 lookupCache,
                 content = new Container { RelativeSizeAxes = Axes.Both }
             });
@@ -59,7 +59,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
                 foreach (var (userId, clock) in clocks)
                 {
-                    streamingClient.EndPlay(userId, 0);
+                    spectatorClient.EndPlay(userId);
                     clock.CurrentTime = 0;
                 }
             });
@@ -67,7 +67,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddStep("create leaderboard", () =>
             {
                 foreach (var (userId, _) in clocks)
-                    streamingClient.StartPlay(userId, 0);
+                    spectatorClient.StartPlay(userId, 0);
 
                 Beatmap.Value = CreateWorkingBeatmap(Ruleset.Value);
 
@@ -96,10 +96,10 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 // For player 2, send frames in sets of 10.
                 for (int i = 0; i < 100; i++)
                 {
-                    streamingClient.SendFrames(PLAYER_1_ID, i, 1);
+                    spectatorClient.SendFrames(PLAYER_1_ID, i, 1);
 
                     if (i % 10 == 0)
-                        streamingClient.SendFrames(PLAYER_2_ID, i, 10);
+                        spectatorClient.SendFrames(PLAYER_2_ID, i, 10);
                 }
             });
 

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorScreen.cs

@@ -22,8 +22,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
 {
     public class TestSceneMultiSpectatorScreen : MultiplayerTestScene
     {
-        [Cached(typeof(SpectatorStreamingClient))]
+        [Cached(typeof(SpectatorClient))]
-        private TestSpectatorStreamingClient streamingClient = new TestSpectatorStreamingClient();
+        private TestSpectatorClient spectatorClient = new TestSpectatorClient();
 
         [Cached(typeof(UserLookupCache))]
         private UserLookupCache lookupCache = new TestUserLookupCache();
@@ -59,14 +59,14 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             AddStep("add streaming client", () =>
             {
-                Remove(streamingClient);
+                Remove(spectatorClient);
-                Add(streamingClient);
+                Add(spectatorClient);
             });
 
             AddStep("finish previous gameplay", () =>
             {
                 foreach (var id in playingUserIds)
-                    streamingClient.EndPlay(id, importedBeatmapId);
+                    spectatorClient.EndPlay(id);
                 playingUserIds.Clear();
             });
         }
@@ -87,11 +87,11 @@ namespace osu.Game.Tests.Visual.Multiplayer
             loadSpectateScreen(false);
 
             AddWaitStep("wait a bit", 10);
-            AddStep("load player first_player_id", () => streamingClient.StartPlay(PLAYER_1_ID, importedBeatmapId));
+            AddStep("load player first_player_id", () => spectatorClient.StartPlay(PLAYER_1_ID, importedBeatmapId));
             AddUntilStep("one player added", () => spectatorScreen.ChildrenOfType<Player>().Count() == 1);
 
             AddWaitStep("wait a bit", 10);
-            AddStep("load player second_player_id", () => streamingClient.StartPlay(PLAYER_2_ID, importedBeatmapId));
+            AddStep("load player second_player_id", () => spectatorClient.StartPlay(PLAYER_2_ID, importedBeatmapId));
             AddUntilStep("two players added", () => spectatorScreen.ChildrenOfType<Player>().Count() == 2);
         }
 
@@ -251,18 +251,18 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 foreach (int id in userIds)
                 {
                     Client.CurrentMatchPlayingUserIds.Add(id);
-                    streamingClient.StartPlay(id, beatmapId ?? importedBeatmapId);
+                    spectatorClient.StartPlay(id, beatmapId ?? importedBeatmapId);
                     playingUserIds.Add(id);
                     nextFrame[id] = 0;
                 }
             });
         }
 
-        private void finish(int userId, int? beatmapId = null)
+        private void finish(int userId)
         {
             AddStep("end play", () =>
             {
-                streamingClient.EndPlay(userId, beatmapId ?? importedBeatmapId);
+                spectatorClient.EndPlay(userId);
                 playingUserIds.Remove(userId);
                 nextFrame.Remove(userId);
             });
@@ -276,7 +276,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             {
                 foreach (int id in userIds)
                 {
-                    streamingClient.SendFrames(id, nextFrame[id], count);
+                    spectatorClient.SendFrames(id, nextFrame[id], count);
                     nextFrame[id] += count;
                 }
             });

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayer.cs

@@ -195,7 +195,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
         private class TestMultiplayer : Screens.OnlinePlay.Multiplayer.Multiplayer
         {
-            [Cached(typeof(StatefulMultiplayerClient))]
+            [Cached(typeof(MultiplayerClient))]
             public readonly TestMultiplayerClient Client;
 
             public TestMultiplayer()

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboard.cs

@@ -28,8 +28,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
     {
         private const int users = 16;
 
-        [Cached(typeof(SpectatorStreamingClient))]
+        [Cached(typeof(SpectatorClient))]
-        private TestMultiplayerStreaming streamingClient = new TestMultiplayerStreaming();
+        private TestMultiplayerSpectatorClient spectatorClient = new TestMultiplayerSpectatorClient();
 
         [Cached(typeof(UserLookupCache))]
         private UserLookupCache lookupCache = new TestSceneCurrentlyPlayingDisplay.TestUserLookupCache();
@@ -44,7 +44,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             base.Content.Children = new Drawable[]
             {
-                streamingClient,
+                spectatorClient,
                 lookupCache,
                 Content
             };
@@ -71,10 +71,10 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 var playable = Beatmap.Value.GetPlayableBeatmap(Ruleset.Value);
 
                 for (int i = 0; i < users; i++)
-                    streamingClient.StartPlay(i, Beatmap.Value.BeatmapInfo.OnlineBeatmapID ?? 0);
+                    spectatorClient.StartPlay(i, Beatmap.Value.BeatmapInfo.OnlineBeatmapID ?? 0);
 
                 Client.CurrentMatchPlayingUserIds.Clear();
-                Client.CurrentMatchPlayingUserIds.AddRange(streamingClient.PlayingUsers);
+                Client.CurrentMatchPlayingUserIds.AddRange(spectatorClient.PlayingUsers);
 
                 Children = new Drawable[]
                 {
@@ -83,7 +83,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
                 scoreProcessor.ApplyBeatmap(playable);
 
-                LoadComponentAsync(leaderboard = new MultiplayerGameplayLeaderboard(scoreProcessor, streamingClient.PlayingUsers.ToArray())
+                LoadComponentAsync(leaderboard = new MultiplayerGameplayLeaderboard(scoreProcessor, spectatorClient.PlayingUsers.ToArray())
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
@@ -96,7 +96,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestScoreUpdates()
         {
-            AddRepeatStep("update state", () => streamingClient.RandomlyUpdateState(), 100);
+            AddRepeatStep("update state", () => spectatorClient.RandomlyUpdateState(), 100);
             AddToggleStep("switch compact mode", expanded => leaderboard.Expanded.Value = expanded);
         }
 
@@ -109,12 +109,12 @@ namespace osu.Game.Tests.Visual.Multiplayer
         [Test]
         public void TestChangeScoringMode()
         {
-            AddRepeatStep("update state", () => streamingClient.RandomlyUpdateState(), 5);
+            AddRepeatStep("update state", () => spectatorClient.RandomlyUpdateState(), 5);
             AddStep("change to classic", () => config.SetValue(OsuSetting.ScoreDisplayMode, ScoringMode.Classic));
             AddStep("change to standardised", () => config.SetValue(OsuSetting.ScoreDisplayMode, ScoringMode.Standardised));
         }
 
-        public class TestMultiplayerStreaming : TestSpectatorStreamingClient
+        public class TestMultiplayerSpectatorClient : TestSpectatorClient
         {
             private readonly Dictionary<int, FrameHeader> lastHeaders = new Dictionary<int, FrameHeader>();
 

osu.Game.Tests/Visual/Online/TestSceneAccountCreationOverlay.cs

@@ -1,12 +1,16 @@
 // 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 NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Framework.Testing;
 using osu.Game.Overlays;
+using osu.Game.Overlays.AccountCreation;
+using osu.Game.Overlays.Settings;
 using osu.Game.Users;
 
 namespace osu.Game.Tests.Visual.Online
@@ -36,8 +40,6 @@ namespace osu.Game.Tests.Visual.Online
         [BackgroundDependencyLoader]
         private void load()
         {
-            API.Logout();
-
             localUser = API.LocalUser.GetBoundCopy();
             localUser.BindValueChanged(user => { userPanelArea.Child = new UserGridPanel(user.NewValue) { Width = 200 }; }, true);
         }
@@ -46,11 +48,14 @@ namespace osu.Game.Tests.Visual.Online
         public void TestOverlayVisibility()
         {
             AddStep("start hidden", () => accountCreation.Hide());
-            AddStep("log out", API.Logout);
+            AddStep("log out", () => API.Logout());
 
             AddStep("show manually", () => accountCreation.Show());
             AddUntilStep("overlay is visible", () => accountCreation.State.Value == Visibility.Visible);
 
+            AddStep("click button", () => accountCreation.ChildrenOfType<SettingsButton>().Single().Click());
+            AddUntilStep("warning screen is present", () => accountCreation.ChildrenOfType<ScreenWarning>().SingleOrDefault()?.IsPresent == true);
+
             AddStep("log back in", () => API.Login("dummy", "password"));
             AddUntilStep("overlay is hidden", () => accountCreation.State.Value == Visibility.Hidden);
         }

osu.Game.Tests/Visual/Online/TestSceneCurrentlyPlayingDisplay.cs

@@ -19,8 +19,10 @@ namespace osu.Game.Tests.Visual.Online
 {
     public class TestSceneCurrentlyPlayingDisplay : OsuTestScene
     {
-        [Cached(typeof(SpectatorStreamingClient))]
+        private readonly User streamingUser = new User { Id = 2, Username = "Test user" };
-        private TestSpectatorStreamingClient testSpectatorStreamingClient = new TestSpectatorStreamingClient();
+
+        [Cached(typeof(SpectatorClient))]
+        private TestSpectatorClient testSpectatorClient = new TestSpectatorClient();
 
         private CurrentlyPlayingDisplay currentlyPlaying;
 
@@ -34,7 +36,7 @@ namespace osu.Game.Tests.Visual.Online
         {
             AddStep("add streaming client", () =>
             {
-                nestedContainer?.Remove(testSpectatorStreamingClient);
+                nestedContainer?.Remove(testSpectatorClient);
                 Remove(lookupCache);
 
                 Children = new Drawable[]
@@ -45,7 +47,7 @@ namespace osu.Game.Tests.Visual.Online
                         RelativeSizeAxes = Axes.Both,
                         Children = new Drawable[]
                         {
-                            testSpectatorStreamingClient,
+                            testSpectatorClient,
                             currentlyPlaying = new CurrentlyPlayingDisplay
                             {
                                 RelativeSizeAxes = Axes.Both,
@@ -55,15 +57,15 @@ namespace osu.Game.Tests.Visual.Online
                 };
             });
 
-            AddStep("Reset players", () => testSpectatorStreamingClient.PlayingUsers.Clear());
+            AddStep("Reset players", () => testSpectatorClient.EndPlay(streamingUser.Id));
         }
 
         [Test]
         public void TestBasicDisplay()
         {
-            AddStep("Add playing user", () => testSpectatorStreamingClient.PlayingUsers.Add(2));
+            AddStep("Add playing user", () => testSpectatorClient.StartPlay(streamingUser.Id, 0));
             AddUntilStep("Panel loaded", () => currentlyPlaying.ChildrenOfType<UserGridPanel>()?.FirstOrDefault()?.User.Id == 2);
-            AddStep("Remove playing user", () => testSpectatorStreamingClient.PlayingUsers.Remove(2));
+            AddStep("Remove playing user", () => testSpectatorClient.EndPlay(streamingUser.Id));
             AddUntilStep("Panel no longer present", () => !currentlyPlaying.ChildrenOfType<UserGridPanel>().Any());
         }
 

osu.Game.Tests/Visual/UserInterface/TestSceneStatefulMenuItem.cs

@@ -14,7 +14,7 @@ namespace osu.Game.Tests.Visual.UserInterface
     public class TestSceneStatefulMenuItem : OsuManualInputManagerTestScene
     {
         [Test]
-        public void TestTernaryMenuItem()
+        public void TestTernaryRadioMenuItem()
         {
             OsuMenu menu = null;
 
@@ -30,9 +30,57 @@ namespace osu.Game.Tests.Visual.UserInterface
                     Origin = Anchor.Centre,
                     Items = new[]
                     {
-                        new TernaryStateMenuItem("First"),
+                        new TernaryStateRadioMenuItem("First"),
-                        new TernaryStateMenuItem("Second") { State = { BindTarget = state } },
+                        new TernaryStateRadioMenuItem("Second") { State = { BindTarget = state } },
-                        new TernaryStateMenuItem("Third") { State = { Value = TernaryState.True } },
+                        new TernaryStateRadioMenuItem("Third") { State = { Value = TernaryState.True } },
+                    }
+                };
+            });
+
+            checkState(TernaryState.Indeterminate);
+
+            click();
+            checkState(TernaryState.True);
+
+            click();
+            checkState(TernaryState.True);
+
+            click();
+            checkState(TernaryState.True);
+
+            AddStep("change state via bindable", () => state.Value = TernaryState.True);
+
+            void click() =>
+                AddStep("click", () =>
+                {
+                    InputManager.MoveMouseTo(menu.ScreenSpaceDrawQuad.Centre);
+                    InputManager.Click(MouseButton.Left);
+                });
+
+            void checkState(TernaryState expected)
+                => AddAssert($"state is {expected}", () => state.Value == expected);
+        }
+
+        [Test]
+        public void TestTernaryToggleMenuItem()
+        {
+            OsuMenu menu = null;
+
+            Bindable<TernaryState> state = new Bindable<TernaryState>(TernaryState.Indeterminate);
+
+            AddStep("create menu", () =>
+            {
+                state.Value = TernaryState.Indeterminate;
+
+                Child = menu = new OsuMenu(Direction.Vertical, true)
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    Items = new[]
+                    {
+                        new TernaryStateToggleMenuItem("First"),
+                        new TernaryStateToggleMenuItem("Second") { State = { BindTarget = state } },
+                        new TernaryStateToggleMenuItem("Third") { State = { Value = TernaryState.True } },
                     }
                 };
             });

osu.Game/Configuration/OsuConfigManager.cs

@@ -104,7 +104,6 @@ namespace osu.Game.Configuration
             SetDefault(OsuSetting.KeyOverlay, false);
             SetDefault(OsuSetting.PositionalHitSounds, true);
             SetDefault(OsuSetting.AlwaysPlayFirstComboBreak, true);
-            SetDefault(OsuSetting.ScoreMeter, ScoreMeterType.HitErrorBoth);
 
             SetDefault(OsuSetting.FloatingComments, false);
 
@@ -213,7 +212,6 @@ namespace osu.Game.Configuration
         KeyOverlay,
         PositionalHitSounds,
         AlwaysPlayFirstComboBreak,
-        ScoreMeter,
         FloatingComments,
         HUDVisibilityMode,
         ShowProgressGraph,

osu.Game/Configuration/ScoreMeterType.cs

@@ -1,37 +0,0 @@
-// 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.ComponentModel;
-
-namespace osu.Game.Configuration
-{
-    public enum ScoreMeterType
-    {
-        [Description("None")]
-        None,
-
-        [Description("Hit Error (left)")]
-        HitErrorLeft,
-
-        [Description("Hit Error (right)")]
-        HitErrorRight,
-
-        [Description("Hit Error (left+right)")]
-        HitErrorBoth,
-
-        [Description("Hit Error (bottom)")]
-        HitErrorBottom,
-
-        [Description("Colour (left)")]
-        ColourLeft,
-
-        [Description("Colour (right)")]
-        ColourRight,
-
-        [Description("Colour (left+right)")]
-        ColourBoth,
-
-        [Description("Colour (bottom)")]
-        ColourBottom,
-    }
-}

osu.Game/Graphics/UserInterface/TernaryStateMenuItem.cs

@@ -9,28 +9,17 @@ namespace osu.Game.Graphics.UserInterface
     /// <summary>
     /// An <see cref="OsuMenuItem"/> with three possible states.
     /// </summary>
-    public class TernaryStateMenuItem : StatefulMenuItem<TernaryState>
+    public abstract class TernaryStateMenuItem : StatefulMenuItem<TernaryState>
     {
         /// <summary>
         /// Creates a new <see cref="TernaryStateMenuItem"/>.
         /// </summary>
         /// <param name="text">The text to display.</param>
+        /// <param name="nextStateFunction">A function to inform what the next state should be when this item is clicked.</param>
         /// <param name="type">The type of action which this <see cref="TernaryStateMenuItem"/> performs.</param>
         /// <param name="action">A delegate to be invoked when this <see cref="TernaryStateMenuItem"/> is pressed.</param>
-        public TernaryStateMenuItem(string text, MenuItemType type = MenuItemType.Standard, Action<TernaryState> action = null)
+        protected TernaryStateMenuItem(string text, Func<TernaryState, TernaryState> nextStateFunction, MenuItemType type = MenuItemType.Standard, Action<TernaryState> action = null)
-            : this(text, getNextState, type, action)
+            : base(text, nextStateFunction, type, action)
-        {
-        }
-
-        /// <summary>
-        /// Creates a new <see cref="TernaryStateMenuItem"/>.
-        /// </summary>
-        /// <param name="text">The text to display.</param>
-        /// <param name="changeStateFunc">A function that mutates a state to another state after this <see cref="TernaryStateMenuItem"/> is pressed.</param>
-        /// <param name="type">The type of action which this <see cref="TernaryStateMenuItem"/> performs.</param>
-        /// <param name="action">A delegate to be invoked when this <see cref="TernaryStateMenuItem"/> is pressed.</param>
-        protected TernaryStateMenuItem(string text, Func<TernaryState, TernaryState> changeStateFunc, MenuItemType type, Action<TernaryState> action)
-            : base(text, changeStateFunc, type, action)
         {
         }
 
@@ -47,23 +36,5 @@ namespace osu.Game.Graphics.UserInterface
 
             return null;
         }
-
-        private static TernaryState getNextState(TernaryState state)
-        {
-            switch (state)
-            {
-                case TernaryState.False:
-                    return TernaryState.True;
-
-                case TernaryState.Indeterminate:
-                    return TernaryState.True;
-
-                case TernaryState.True:
-                    return TernaryState.False;
-
-                default:
-                    throw new ArgumentOutOfRangeException(nameof(state), state, null);
-            }
-        }
     }
 }

osu.Game/Graphics/UserInterface/TernaryStateRadioMenuItem.cs

@@ -0,0 +1,26 @@
+// 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;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    /// <summary>
+    /// A ternary state menu item which will always set the item to <c>true</c> on click, even if already <c>true</c>.
+    /// </summary>
+    public class TernaryStateRadioMenuItem : TernaryStateMenuItem
+    {
+        /// <summary>
+        /// Creates a new <see cref="TernaryStateMenuItem"/>.
+        /// </summary>
+        /// <param name="text">The text to display.</param>
+        /// <param name="type">The type of action which this <see cref="TernaryStateMenuItem"/> performs.</param>
+        /// <param name="action">A delegate to be invoked when this <see cref="TernaryStateMenuItem"/> is pressed.</param>
+        public TernaryStateRadioMenuItem(string text, MenuItemType type = MenuItemType.Standard, Action<TernaryState> action = null)
+            : base(text, getNextState, type, action)
+        {
+        }
+
+        private static TernaryState getNextState(TernaryState state) => TernaryState.True;
+    }
+}

osu.Game/Graphics/UserInterface/TernaryStateToggleMenuItem.cs

@@ -0,0 +1,42 @@
+// 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;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    /// <summary>
+    /// A ternary state menu item which toggles the state of this item <c>false</c> if clicked when <c>true</c>.
+    /// </summary>
+    public class TernaryStateToggleMenuItem : TernaryStateMenuItem
+    {
+        /// <summary>
+        /// Creates a new <see cref="TernaryStateToggleMenuItem"/>.
+        /// </summary>
+        /// <param name="text">The text to display.</param>
+        /// <param name="type">The type of action which this <see cref="TernaryStateMenuItem"/> performs.</param>
+        /// <param name="action">A delegate to be invoked when this <see cref="TernaryStateMenuItem"/> is pressed.</param>
+        public TernaryStateToggleMenuItem(string text, MenuItemType type = MenuItemType.Standard, Action<TernaryState> action = null)
+            : base(text, getNextState, type, action)
+        {
+        }
+
+        private static TernaryState getNextState(TernaryState state)
+        {
+            switch (state)
+            {
+                case TernaryState.False:
+                    return TernaryState.True;
+
+                case TernaryState.Indeterminate:
+                    return TernaryState.True;
+
+                case TernaryState.True:
+                    return TernaryState.False;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(state), state, null);
+            }
+        }
+    }
+}

osu.Game/Online/Multiplayer/MultiplayerClient.cs

@@ -3,132 +3,621 @@
 
 #nullable enable
 
+using System;
 using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.SignalR.Client;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Framework.Graphics;
+using osu.Framework.Logging;
 using osu.Game.Beatmaps;
+using osu.Game.Database;
 using osu.Game.Online.API;
-using osu.Game.Online.API.Requests;
 using osu.Game.Online.Rooms;
+using osu.Game.Online.Rooms.RoomStatuses;
+using osu.Game.Rulesets;
+using osu.Game.Rulesets.Mods;
+using osu.Game.Users;
+using osu.Game.Utils;
 
 namespace osu.Game.Online.Multiplayer
 {
-    public class MultiplayerClient : StatefulMultiplayerClient
+    public abstract class MultiplayerClient : Component, IMultiplayerClient, IMultiplayerRoomServer
     {
-        private readonly string endpoint;
+        /// <summary>
+        /// Invoked when any change occurs to the multiplayer room.
+        /// </summary>
+        public event Action? RoomUpdated;
 
-        private IHubClientConnector? connector;
+        /// <summary>
+        /// Invoked when the multiplayer server requests the current beatmap to be loaded into play.
+        /// </summary>
+        public event Action? LoadRequested;
 
-        public override IBindable<bool> IsConnected { get; } = new BindableBool();
+        /// <summary>
+        /// Invoked when the multiplayer server requests gameplay to be started.
+        /// </summary>
+        public event Action? MatchStarted;
 
-        private HubConnection? connection => connector?.CurrentConnection;
+        /// <summary>
+        /// Invoked when the multiplayer server has finished collating results.
+        /// </summary>
+        public event Action? ResultsReady;
 
-        public MultiplayerClient(EndpointConfiguration endpoints)
+        /// <summary>
+        /// Whether the <see cref="MultiplayerClient"/> is currently connected.
+        /// This is NOT thread safe and usage should be scheduled.
+        /// </summary>
+        public abstract IBindable<bool> IsConnected { get; }
+
+        /// <summary>
+        /// The joined <see cref="MultiplayerRoom"/>.
+        /// </summary>
+        public MultiplayerRoom? Room { get; private set; }
+
+        /// <summary>
+        /// The users in the joined <see cref="Room"/> which are participating in the current gameplay loop.
+        /// </summary>
+        public readonly BindableList<int> CurrentMatchPlayingUserIds = new BindableList<int>();
+
+        public readonly Bindable<PlaylistItem?> CurrentMatchPlayingItem = new Bindable<PlaylistItem?>();
+
+        /// <summary>
+        /// The <see cref="MultiplayerRoomUser"/> corresponding to the local player, if available.
+        /// </summary>
+        public MultiplayerRoomUser? LocalUser => Room?.Users.SingleOrDefault(u => u.User?.Id == API.LocalUser.Value.Id);
+
+        /// <summary>
+        /// Whether the <see cref="LocalUser"/> is the host in <see cref="Room"/>.
+        /// </summary>
+        public bool IsHost
         {
-            endpoint = endpoints.MultiplayerEndpointUrl;
+            get
+            {
+                var localUser = LocalUser;
+                return localUser != null && Room?.Host != null && localUser.Equals(Room.Host);
             }
+        }
+
+        [Resolved]
+        protected IAPIProvider API { get; private set; } = null!;
+
+        [Resolved]
+        protected RulesetStore Rulesets { get; private set; } = null!;
+
+        [Resolved]
+        private UserLookupCache userLookupCache { get; set; } = null!;
+
+        private Room? apiRoom;
 
         [BackgroundDependencyLoader]
-        private void load(IAPIProvider api)
+        private void load()
         {
-            connector = api.GetHubConnector(nameof(MultiplayerClient), endpoint);
+            IsConnected.BindValueChanged(connected =>
+            {
+                // clean up local room state on server disconnect.
+                if (!connected.NewValue && Room != null)
+                {
+                    Logger.Log("Connection to multiplayer server was lost.", LoggingTarget.Runtime, LogLevel.Important);
+                    LeaveRoom();
+                }
+            });
+        }
 
-            if (connector != null)
+        private readonly TaskChain joinOrLeaveTaskChain = new TaskChain();
+        private CancellationTokenSource? joinCancellationSource;
+
+        /// <summary>
+        /// Joins the <see cref="MultiplayerRoom"/> for a given API <see cref="Room"/>.
+        /// </summary>
+        /// <param name="room">The API <see cref="Room"/>.</param>
+        public async Task JoinRoom(Room room)
         {
-                connector.ConfigureConnection = connection =>
+            var cancellationSource = joinCancellationSource = new CancellationTokenSource();
+
+            await joinOrLeaveTaskChain.Add(async () =>
             {
-                    // this is kind of SILLY
+                if (Room != null)
-                    // https://github.com/dotnet/aspnetcore/issues/15198
+                    throw new InvalidOperationException("Cannot join a multiplayer room while already in one.");
-                    connection.On<MultiplayerRoomState>(nameof(IMultiplayerClient.RoomStateChanged), ((IMultiplayerClient)this).RoomStateChanged);
+
-                    connection.On<MultiplayerRoomUser>(nameof(IMultiplayerClient.UserJoined), ((IMultiplayerClient)this).UserJoined);
+                Debug.Assert(room.RoomID.Value != null);
-                    connection.On<MultiplayerRoomUser>(nameof(IMultiplayerClient.UserLeft), ((IMultiplayerClient)this).UserLeft);
+
-                    connection.On<int>(nameof(IMultiplayerClient.HostChanged), ((IMultiplayerClient)this).HostChanged);
+                // Join the server-side room.
-                    connection.On<MultiplayerRoomSettings>(nameof(IMultiplayerClient.SettingsChanged), ((IMultiplayerClient)this).SettingsChanged);
+                var joinedRoom = await JoinRoom(room.RoomID.Value.Value).ConfigureAwait(false);
-                    connection.On<int, MultiplayerUserState>(nameof(IMultiplayerClient.UserStateChanged), ((IMultiplayerClient)this).UserStateChanged);
+                Debug.Assert(joinedRoom != null);
-                    connection.On(nameof(IMultiplayerClient.LoadRequested), ((IMultiplayerClient)this).LoadRequested);
+
-                    connection.On(nameof(IMultiplayerClient.MatchStarted), ((IMultiplayerClient)this).MatchStarted);
+                // Populate users.
-                    connection.On(nameof(IMultiplayerClient.ResultsReady), ((IMultiplayerClient)this).ResultsReady);
+                Debug.Assert(joinedRoom.Users != null);
-                    connection.On<int, IEnumerable<APIMod>>(nameof(IMultiplayerClient.UserModsChanged), ((IMultiplayerClient)this).UserModsChanged);
+                await Task.WhenAll(joinedRoom.Users.Select(PopulateUser)).ConfigureAwait(false);
-                    connection.On<int, BeatmapAvailability>(nameof(IMultiplayerClient.UserBeatmapAvailabilityChanged), ((IMultiplayerClient)this).UserBeatmapAvailabilityChanged);
+
+                // Update the stored room (must be done on update thread for thread-safety).
+                await scheduleAsync(() =>
+                {
+                    Room = joinedRoom;
+                    apiRoom = room;
+                    foreach (var user in joinedRoom.Users)
+                        updateUserPlayingState(user.UserID, user.State);
+                }, cancellationSource.Token).ConfigureAwait(false);
+
+                // Update room settings.
+                await updateLocalRoomSettings(joinedRoom.Settings, cancellationSource.Token).ConfigureAwait(false);
+            }, cancellationSource.Token).ConfigureAwait(false);
+        }
+
+        /// <summary>
+        /// Joins the <see cref="MultiplayerRoom"/> with a given ID.
+        /// </summary>
+        /// <param name="roomId">The room ID.</param>
+        /// <returns>The joined <see cref="MultiplayerRoom"/>.</returns>
+        protected abstract Task<MultiplayerRoom> JoinRoom(long roomId);
+
+        public Task LeaveRoom()
+        {
+            // The join may have not completed yet, so certain tasks that either update the room or reference the room should be cancelled.
+            // This includes the setting of Room itself along with the initial update of the room settings on join.
+            joinCancellationSource?.Cancel();
+
+            // Leaving rooms is expected to occur instantaneously whilst the operation is finalised in the background.
+            // However a few members need to be reset immediately to prevent other components from entering invalid states whilst the operation hasn't yet completed.
+            // For example, if a room was left and the user immediately pressed the "create room" button, then the user could be taken into the lobby if the value of Room is not reset in time.
+            var scheduledReset = scheduleAsync(() =>
+            {
+                apiRoom = null;
+                Room = null;
+                CurrentMatchPlayingUserIds.Clear();
+
+                RoomUpdated?.Invoke();
+            });
+
+            return joinOrLeaveTaskChain.Add(async () =>
+            {
+                await scheduledReset.ConfigureAwait(false);
+                await LeaveRoomInternal().ConfigureAwait(false);
+            });
+        }
+
+        protected abstract Task LeaveRoomInternal();
+
+        /// <summary>
+        /// Change the current <see cref="MultiplayerRoom"/> settings.
+        /// </summary>
+        /// <remarks>
+        /// A room must be joined for this to have any effect.
+        /// </remarks>
+        /// <param name="name">The new room name, if any.</param>
+        /// <param name="item">The new room playlist item, if any.</param>
+        public Task ChangeSettings(Optional<string> name = default, Optional<PlaylistItem> item = default)
+        {
+            if (Room == null)
+                throw new InvalidOperationException("Must be joined to a match to change settings.");
+
+            // A dummy playlist item filled with the current room settings (except mods).
+            var existingPlaylistItem = new PlaylistItem
+            {
+                Beatmap =
+                {
+                    Value = new BeatmapInfo
+                    {
+                        OnlineBeatmapID = Room.Settings.BeatmapID,
+                        MD5Hash = Room.Settings.BeatmapChecksum
+                    }
+                },
+                RulesetID = Room.Settings.RulesetID
             };
 
-                IsConnected.BindTo(connector.IsConnected);
+            return ChangeSettings(new MultiplayerRoomSettings
-            }
-        }
-
-        protected override Task<MultiplayerRoom> JoinRoom(long roomId)
             {
-            if (!IsConnected.Value)
+                Name = name.GetOr(Room.Settings.Name),
-                return Task.FromCanceled<MultiplayerRoom>(new CancellationToken(true));
+                BeatmapID = item.GetOr(existingPlaylistItem).BeatmapID,
-
+                BeatmapChecksum = item.GetOr(existingPlaylistItem).Beatmap.Value.MD5Hash,
-            return connection.InvokeAsync<MultiplayerRoom>(nameof(IMultiplayerServer.JoinRoom), roomId);
+                RulesetID = item.GetOr(existingPlaylistItem).RulesetID,
+                RequiredMods = item.HasValue ? item.Value.AsNonNull().RequiredMods.Select(m => new APIMod(m)).ToList() : Room.Settings.RequiredMods,
+                AllowedMods = item.HasValue ? item.Value.AsNonNull().AllowedMods.Select(m => new APIMod(m)).ToList() : Room.Settings.AllowedMods,
+            });
         }
 
-        protected override Task LeaveRoomInternal()
+        /// <summary>
+        /// Toggles the <see cref="LocalUser"/>'s ready state.
+        /// </summary>
+        /// <exception cref="InvalidOperationException">If a toggle of ready state is not valid at this time.</exception>
+        public async Task ToggleReady()
         {
-            if (!IsConnected.Value)
+            var localUser = LocalUser;
-                return Task.FromCanceled(new CancellationToken(true));
 
-            return connection.InvokeAsync(nameof(IMultiplayerServer.LeaveRoom));
+            if (localUser == null)
+                return;
+
+            switch (localUser.State)
+            {
+                case MultiplayerUserState.Idle:
+                    await ChangeState(MultiplayerUserState.Ready).ConfigureAwait(false);
+                    return;
+
+                case MultiplayerUserState.Ready:
+                    await ChangeState(MultiplayerUserState.Idle).ConfigureAwait(false);
+                    return;
+
+                default:
+                    throw new InvalidOperationException($"Cannot toggle ready when in {localUser.State}");
+            }
         }
 
-        public override Task TransferHost(int userId)
+        /// <summary>
+        /// Toggles the <see cref="LocalUser"/>'s spectating state.
+        /// </summary>
+        /// <exception cref="InvalidOperationException">If a toggle of the spectating state is not valid at this time.</exception>
+        public async Task ToggleSpectate()
         {
-            if (!IsConnected.Value)
+            var localUser = LocalUser;
+
+            if (localUser == null)
+                return;
+
+            switch (localUser.State)
+            {
+                case MultiplayerUserState.Idle:
+                case MultiplayerUserState.Ready:
+                    await ChangeState(MultiplayerUserState.Spectating).ConfigureAwait(false);
+                    return;
+
+                case MultiplayerUserState.Spectating:
+                    await ChangeState(MultiplayerUserState.Idle).ConfigureAwait(false);
+                    return;
+
+                default:
+                    throw new InvalidOperationException($"Cannot toggle spectate when in {localUser.State}");
+            }
+        }
+
+        public abstract Task TransferHost(int userId);
+
+        public abstract Task ChangeSettings(MultiplayerRoomSettings settings);
+
+        public abstract Task ChangeState(MultiplayerUserState newState);
+
+        public abstract Task ChangeBeatmapAvailability(BeatmapAvailability newBeatmapAvailability);
+
+        /// <summary>
+        /// Change the local user's mods in the currently joined room.
+        /// </summary>
+        /// <param name="newMods">The proposed new mods, excluding any required by the room itself.</param>
+        public Task ChangeUserMods(IEnumerable<Mod> newMods) => ChangeUserMods(newMods.Select(m => new APIMod(m)).ToList());
+
+        public abstract Task ChangeUserMods(IEnumerable<APIMod> newMods);
+
+        public abstract Task StartMatch();
+
+        Task IMultiplayerClient.RoomStateChanged(MultiplayerRoomState state)
+        {
+            if (Room == null)
                 return Task.CompletedTask;
 
-            return connection.InvokeAsync(nameof(IMultiplayerServer.TransferHost), userId);
+            Scheduler.Add(() =>
+            {
+                if (Room == null)
+                    return;
+
+                Debug.Assert(apiRoom != null);
+
+                Room.State = state;
+
+                switch (state)
+                {
+                    case MultiplayerRoomState.Open:
+                        apiRoom.Status.Value = new RoomStatusOpen();
+                        break;
+
+                    case MultiplayerRoomState.Playing:
+                        apiRoom.Status.Value = new RoomStatusPlaying();
+                        break;
+
+                    case MultiplayerRoomState.Closed:
+                        apiRoom.Status.Value = new RoomStatusEnded();
+                        break;
                 }
 
-        public override Task ChangeSettings(MultiplayerRoomSettings settings)
+                RoomUpdated?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
+        }
+
+        async Task IMultiplayerClient.UserJoined(MultiplayerRoomUser user)
         {
-            if (!IsConnected.Value)
+            if (Room == null)
+                return;
+
+            await PopulateUser(user).ConfigureAwait(false);
+
+            Scheduler.Add(() =>
+            {
+                if (Room == null)
+                    return;
+
+                // for sanity, ensure that there can be no duplicate users in the room user list.
+                if (Room.Users.Any(existing => existing.UserID == user.UserID))
+                    return;
+
+                Room.Users.Add(user);
+
+                RoomUpdated?.Invoke();
+            }, false);
+        }
+
+        Task IMultiplayerClient.UserLeft(MultiplayerRoomUser user)
+        {
+            if (Room == null)
                 return Task.CompletedTask;
 
-            return connection.InvokeAsync(nameof(IMultiplayerServer.ChangeSettings), settings);
+            Scheduler.Add(() =>
+            {
+                if (Room == null)
+                    return;
+
+                Room.Users.Remove(user);
+                CurrentMatchPlayingUserIds.Remove(user.UserID);
+
+                RoomUpdated?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
         }
 
-        public override Task ChangeState(MultiplayerUserState newState)
+        Task IMultiplayerClient.HostChanged(int userId)
         {
-            if (!IsConnected.Value)
+            if (Room == null)
                 return Task.CompletedTask;
 
-            return connection.InvokeAsync(nameof(IMultiplayerServer.ChangeState), newState);
+            Scheduler.Add(() =>
+            {
+                if (Room == null)
+                    return;
+
+                Debug.Assert(apiRoom != null);
+
+                var user = Room.Users.FirstOrDefault(u => u.UserID == userId);
+
+                Room.Host = user;
+                apiRoom.Host.Value = user?.User;
+
+                RoomUpdated?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
         }
 
-        public override Task ChangeBeatmapAvailability(BeatmapAvailability newBeatmapAvailability)
+        Task IMultiplayerClient.SettingsChanged(MultiplayerRoomSettings newSettings)
         {
-            if (!IsConnected.Value)
+            updateLocalRoomSettings(newSettings);
+            return Task.CompletedTask;
+        }
+
+        Task IMultiplayerClient.UserStateChanged(int userId, MultiplayerUserState state)
+        {
+            if (Room == null)
                 return Task.CompletedTask;
 
-            return connection.InvokeAsync(nameof(IMultiplayerServer.ChangeBeatmapAvailability), newBeatmapAvailability);
+            Scheduler.Add(() =>
+            {
+                if (Room == null)
+                    return;
+
+                Room.Users.Single(u => u.UserID == userId).State = state;
+
+                updateUserPlayingState(userId, state);
+
+                RoomUpdated?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
         }
 
-        public override Task ChangeUserMods(IEnumerable<APIMod> newMods)
+        Task IMultiplayerClient.UserBeatmapAvailabilityChanged(int userId, BeatmapAvailability beatmapAvailability)
         {
-            if (!IsConnected.Value)
+            if (Room == null)
                 return Task.CompletedTask;
 
-            return connection.InvokeAsync(nameof(IMultiplayerServer.ChangeUserMods), newMods);
+            Scheduler.Add(() =>
+            {
+                var user = Room?.Users.SingleOrDefault(u => u.UserID == userId);
+
+                // errors here are not critical - beatmap availability state is mostly for display.
+                if (user == null)
+                    return;
+
+                user.BeatmapAvailability = beatmapAvailability;
+
+                RoomUpdated?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
         }
 
-        public override Task StartMatch()
+        public Task UserModsChanged(int userId, IEnumerable<APIMod> mods)
         {
-            if (!IsConnected.Value)
+            if (Room == null)
                 return Task.CompletedTask;
 
-            return connection.InvokeAsync(nameof(IMultiplayerServer.StartMatch));
+            Scheduler.Add(() =>
+            {
+                var user = Room?.Users.SingleOrDefault(u => u.UserID == userId);
+
+                // errors here are not critical - user mods are mostly for display.
+                if (user == null)
+                    return;
+
+                user.Mods = mods;
+
+                RoomUpdated?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
         }
 
-        protected override Task<BeatmapSetInfo> GetOnlineBeatmapSet(int beatmapId, CancellationToken cancellationToken = default)
+        Task IMultiplayerClient.LoadRequested()
         {
-            var tcs = new TaskCompletionSource<BeatmapSetInfo>();
+            if (Room == null)
-            var req = new GetBeatmapSetRequest(beatmapId, BeatmapSetLookupType.BeatmapId);
+                return Task.CompletedTask;
 
-            req.Success += res =>
+            Scheduler.Add(() =>
+            {
+                if (Room == null)
+                    return;
+
+                LoadRequested?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
+        }
+
+        Task IMultiplayerClient.MatchStarted()
+        {
+            if (Room == null)
+                return Task.CompletedTask;
+
+            Scheduler.Add(() =>
+            {
+                if (Room == null)
+                    return;
+
+                MatchStarted?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
+        }
+
+        Task IMultiplayerClient.ResultsReady()
+        {
+            if (Room == null)
+                return Task.CompletedTask;
+
+            Scheduler.Add(() =>
+            {
+                if (Room == null)
+                    return;
+
+                ResultsReady?.Invoke();
+            }, false);
+
+            return Task.CompletedTask;
+        }
+
+        /// <summary>
+        /// Populates the <see cref="User"/> for a given <see cref="MultiplayerRoomUser"/>.
+        /// </summary>
+        /// <param name="multiplayerUser">The <see cref="MultiplayerRoomUser"/> to populate.</param>
+        protected async Task PopulateUser(MultiplayerRoomUser multiplayerUser) => multiplayerUser.User ??= await userLookupCache.GetUserAsync(multiplayerUser.UserID).ConfigureAwait(false);
+
+        /// <summary>
+        /// Updates the local room settings with the given <see cref="MultiplayerRoomSettings"/>.
+        /// </summary>
+        /// <remarks>
+        /// This updates both the joined <see cref="MultiplayerRoom"/> and the respective API <see cref="Room"/>.
+        /// </remarks>
+        /// <param name="settings">The new <see cref="MultiplayerRoomSettings"/> to update from.</param>
+        /// <param name="cancellationToken">The <see cref="CancellationToken"/> to cancel the update.</param>
+        private Task updateLocalRoomSettings(MultiplayerRoomSettings settings, CancellationToken cancellationToken = default) => scheduleAsync(() =>
+        {
+            if (Room == null)
+                return;
+
+            Debug.Assert(apiRoom != null);
+
+            // Update a few properties of the room instantaneously.
+            Room.Settings = settings;
+            apiRoom.Name.Value = Room.Settings.Name;
+
+            // The current item update is delayed until an online beatmap lookup (below) succeeds.
+            // In-order for the client to not display an outdated beatmap, the current item is forcefully cleared here.
+            CurrentMatchPlayingItem.Value = null;
+
+            RoomUpdated?.Invoke();
+
+            GetOnlineBeatmapSet(settings.BeatmapID, cancellationToken).ContinueWith(set => Schedule(() =>
+            {
+                if (cancellationToken.IsCancellationRequested)
+                    return;
+
+                updatePlaylist(settings, set.Result);
+            }), TaskContinuationOptions.OnlyOnRanToCompletion);
+        }, cancellationToken);
+
+        private void updatePlaylist(MultiplayerRoomSettings settings, BeatmapSetInfo beatmapSet)
+        {
+            if (Room == null || !Room.Settings.Equals(settings))
+                return;
+
+            Debug.Assert(apiRoom != null);
+
+            var beatmap = beatmapSet.Beatmaps.Single(b => b.OnlineBeatmapID == settings.BeatmapID);
+            beatmap.MD5Hash = settings.BeatmapChecksum;
+
+            var ruleset = Rulesets.GetRuleset(settings.RulesetID).CreateInstance();
+            var mods = settings.RequiredMods.Select(m => m.ToMod(ruleset));
+            var allowedMods = settings.AllowedMods.Select(m => m.ToMod(ruleset));
+
+            // Try to retrieve the existing playlist item from the API room.
+            var playlistItem = apiRoom.Playlist.FirstOrDefault(i => i.ID == settings.PlaylistItemId);
+
+            if (playlistItem != null)
+                updateItem(playlistItem);
+            else
+            {
+                // An existing playlist item does not exist, so append a new one.
+                updateItem(playlistItem = new PlaylistItem());
+                apiRoom.Playlist.Add(playlistItem);
+            }
+
+            CurrentMatchPlayingItem.Value = playlistItem;
+
+            void updateItem(PlaylistItem item)
+            {
+                item.ID = settings.PlaylistItemId;
+                item.Beatmap.Value = beatmap;
+                item.Ruleset.Value = ruleset.RulesetInfo;
+                item.RequiredMods.Clear();
+                item.RequiredMods.AddRange(mods);
+                item.AllowedMods.Clear();
+                item.AllowedMods.AddRange(allowedMods);
+            }
+        }
+
+        /// <summary>
+        /// Retrieves a <see cref="BeatmapSetInfo"/> from an online source.
+        /// </summary>
+        /// <param name="beatmapId">The beatmap set ID.</param>
+        /// <param name="cancellationToken">A token to cancel the request.</param>
+        /// <returns>The <see cref="BeatmapSetInfo"/> retrieval task.</returns>
+        protected abstract Task<BeatmapSetInfo> GetOnlineBeatmapSet(int beatmapId, CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// For the provided user ID, update whether the user is included in <see cref="CurrentMatchPlayingUserIds"/>.
+        /// </summary>
+        /// <param name="userId">The user's ID.</param>
+        /// <param name="state">The new state of the user.</param>
+        private void updateUserPlayingState(int userId, MultiplayerUserState state)
+        {
+            bool wasPlaying = CurrentMatchPlayingUserIds.Contains(userId);
+            bool isPlaying = state >= MultiplayerUserState.WaitingForLoad && state <= MultiplayerUserState.FinishedPlay;
+
+            if (isPlaying == wasPlaying)
+                return;
+
+            if (isPlaying)
+                CurrentMatchPlayingUserIds.Add(userId);
+            else
+                CurrentMatchPlayingUserIds.Remove(userId);
+        }
+
+        private Task scheduleAsync(Action action, CancellationToken cancellationToken = default)
+        {
+            var tcs = new TaskCompletionSource<bool>();
+
+            Scheduler.Add(() =>
             {
                 if (cancellationToken.IsCancellationRequested)
                 {
@@ -136,20 +625,18 @@ namespace osu.Game.Online.Multiplayer
                     return;
                 }
 
-                tcs.SetResult(res.ToBeatmapSet(Rulesets));
+                try
-            };
+                {
-
+                    action();
-            req.Failure += e => tcs.SetException(e);
+                    tcs.SetResult(true);
-
+                }
-            API.Queue(req);
+                catch (Exception ex)
+                {
+                    tcs.SetException(ex);
+                }
+            });
 
             return tcs.Task;
         }
-
-        protected override void Dispose(bool isDisposing)
-        {
-            base.Dispose(isDisposing);
-            connector?.Dispose();
-        }
     }
 }

osu.Game/Online/Multiplayer/OnlineMultiplayerClient.cs

@@ -0,0 +1,158 @@
+// 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.
+
+#nullable enable
+
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.SignalR.Client;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Game.Beatmaps;
+using osu.Game.Online.API;
+using osu.Game.Online.API.Requests;
+using osu.Game.Online.Rooms;
+
+namespace osu.Game.Online.Multiplayer
+{
+    /// <summary>
+    /// A <see cref="MultiplayerClient"/> with online connectivity.
+    /// </summary>
+    public class OnlineMultiplayerClient : MultiplayerClient
+    {
+        private readonly string endpoint;
+
+        private IHubClientConnector? connector;
+
+        public override IBindable<bool> IsConnected { get; } = new BindableBool();
+
+        private HubConnection? connection => connector?.CurrentConnection;
+
+        public OnlineMultiplayerClient(EndpointConfiguration endpoints)
+        {
+            endpoint = endpoints.MultiplayerEndpointUrl;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(IAPIProvider api)
+        {
+            connector = api.GetHubConnector(nameof(OnlineMultiplayerClient), endpoint);
+
+            if (connector != null)
+            {
+                connector.ConfigureConnection = connection =>
+                {
+                    // this is kind of SILLY
+                    // https://github.com/dotnet/aspnetcore/issues/15198
+                    connection.On<MultiplayerRoomState>(nameof(IMultiplayerClient.RoomStateChanged), ((IMultiplayerClient)this).RoomStateChanged);
+                    connection.On<MultiplayerRoomUser>(nameof(IMultiplayerClient.UserJoined), ((IMultiplayerClient)this).UserJoined);
+                    connection.On<MultiplayerRoomUser>(nameof(IMultiplayerClient.UserLeft), ((IMultiplayerClient)this).UserLeft);
+                    connection.On<int>(nameof(IMultiplayerClient.HostChanged), ((IMultiplayerClient)this).HostChanged);
+                    connection.On<MultiplayerRoomSettings>(nameof(IMultiplayerClient.SettingsChanged), ((IMultiplayerClient)this).SettingsChanged);
+                    connection.On<int, MultiplayerUserState>(nameof(IMultiplayerClient.UserStateChanged), ((IMultiplayerClient)this).UserStateChanged);
+                    connection.On(nameof(IMultiplayerClient.LoadRequested), ((IMultiplayerClient)this).LoadRequested);
+                    connection.On(nameof(IMultiplayerClient.MatchStarted), ((IMultiplayerClient)this).MatchStarted);
+                    connection.On(nameof(IMultiplayerClient.ResultsReady), ((IMultiplayerClient)this).ResultsReady);
+                    connection.On<int, IEnumerable<APIMod>>(nameof(IMultiplayerClient.UserModsChanged), ((IMultiplayerClient)this).UserModsChanged);
+                    connection.On<int, BeatmapAvailability>(nameof(IMultiplayerClient.UserBeatmapAvailabilityChanged), ((IMultiplayerClient)this).UserBeatmapAvailabilityChanged);
+                };
+
+                IsConnected.BindTo(connector.IsConnected);
+            }
+        }
+
+        protected override Task<MultiplayerRoom> JoinRoom(long roomId)
+        {
+            if (!IsConnected.Value)
+                return Task.FromCanceled<MultiplayerRoom>(new CancellationToken(true));
+
+            return connection.InvokeAsync<MultiplayerRoom>(nameof(IMultiplayerServer.JoinRoom), roomId);
+        }
+
+        protected override Task LeaveRoomInternal()
+        {
+            if (!IsConnected.Value)
+                return Task.FromCanceled(new CancellationToken(true));
+
+            return connection.InvokeAsync(nameof(IMultiplayerServer.LeaveRoom));
+        }
+
+        public override Task TransferHost(int userId)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.InvokeAsync(nameof(IMultiplayerServer.TransferHost), userId);
+        }
+
+        public override Task ChangeSettings(MultiplayerRoomSettings settings)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.InvokeAsync(nameof(IMultiplayerServer.ChangeSettings), settings);
+        }
+
+        public override Task ChangeState(MultiplayerUserState newState)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.InvokeAsync(nameof(IMultiplayerServer.ChangeState), newState);
+        }
+
+        public override Task ChangeBeatmapAvailability(BeatmapAvailability newBeatmapAvailability)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.InvokeAsync(nameof(IMultiplayerServer.ChangeBeatmapAvailability), newBeatmapAvailability);
+        }
+
+        public override Task ChangeUserMods(IEnumerable<APIMod> newMods)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.InvokeAsync(nameof(IMultiplayerServer.ChangeUserMods), newMods);
+        }
+
+        public override Task StartMatch()
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.InvokeAsync(nameof(IMultiplayerServer.StartMatch));
+        }
+
+        protected override Task<BeatmapSetInfo> GetOnlineBeatmapSet(int beatmapId, CancellationToken cancellationToken = default)
+        {
+            var tcs = new TaskCompletionSource<BeatmapSetInfo>();
+            var req = new GetBeatmapSetRequest(beatmapId, BeatmapSetLookupType.BeatmapId);
+
+            req.Success += res =>
+            {
+                if (cancellationToken.IsCancellationRequested)
+                {
+                    tcs.SetCanceled();
+                    return;
+                }
+
+                tcs.SetResult(res.ToBeatmapSet(Rulesets));
+            };
+
+            req.Failure += e => tcs.SetException(e);
+
+            API.Queue(req);
+
+            return tcs.Task;
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            connector?.Dispose();
+        }
+    }
+}

osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs

@@ -1,642 +0,0 @@
-// 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.
-
-#nullable enable
-
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
-using osu.Framework.Allocation;
-using osu.Framework.Bindables;
-using osu.Framework.Extensions.ObjectExtensions;
-using osu.Framework.Graphics;
-using osu.Framework.Logging;
-using osu.Game.Beatmaps;
-using osu.Game.Database;
-using osu.Game.Online.API;
-using osu.Game.Online.Rooms;
-using osu.Game.Online.Rooms.RoomStatuses;
-using osu.Game.Rulesets;
-using osu.Game.Rulesets.Mods;
-using osu.Game.Users;
-using osu.Game.Utils;
-
-namespace osu.Game.Online.Multiplayer
-{
-    public abstract class StatefulMultiplayerClient : Component, IMultiplayerClient, IMultiplayerRoomServer
-    {
-        /// <summary>
-        /// Invoked when any change occurs to the multiplayer room.
-        /// </summary>
-        public event Action? RoomUpdated;
-
-        /// <summary>
-        /// Invoked when the multiplayer server requests the current beatmap to be loaded into play.
-        /// </summary>
-        public event Action? LoadRequested;
-
-        /// <summary>
-        /// Invoked when the multiplayer server requests gameplay to be started.
-        /// </summary>
-        public event Action? MatchStarted;
-
-        /// <summary>
-        /// Invoked when the multiplayer server has finished collating results.
-        /// </summary>
-        public event Action? ResultsReady;
-
-        /// <summary>
-        /// Whether the <see cref="StatefulMultiplayerClient"/> is currently connected.
-        /// This is NOT thread safe and usage should be scheduled.
-        /// </summary>
-        public abstract IBindable<bool> IsConnected { get; }
-
-        /// <summary>
-        /// The joined <see cref="MultiplayerRoom"/>.
-        /// </summary>
-        public MultiplayerRoom? Room { get; private set; }
-
-        /// <summary>
-        /// The users in the joined <see cref="Room"/> which are participating in the current gameplay loop.
-        /// </summary>
-        public readonly BindableList<int> CurrentMatchPlayingUserIds = new BindableList<int>();
-
-        public readonly Bindable<PlaylistItem?> CurrentMatchPlayingItem = new Bindable<PlaylistItem?>();
-
-        /// <summary>
-        /// The <see cref="MultiplayerRoomUser"/> corresponding to the local player, if available.
-        /// </summary>
-        public MultiplayerRoomUser? LocalUser => Room?.Users.SingleOrDefault(u => u.User?.Id == API.LocalUser.Value.Id);
-
-        /// <summary>
-        /// Whether the <see cref="LocalUser"/> is the host in <see cref="Room"/>.
-        /// </summary>
-        public bool IsHost
-        {
-            get
-            {
-                var localUser = LocalUser;
-                return localUser != null && Room?.Host != null && localUser.Equals(Room.Host);
-            }
-        }
-
-        [Resolved]
-        protected IAPIProvider API { get; private set; } = null!;
-
-        [Resolved]
-        protected RulesetStore Rulesets { get; private set; } = null!;
-
-        [Resolved]
-        private UserLookupCache userLookupCache { get; set; } = null!;
-
-        private Room? apiRoom;
-
-        [BackgroundDependencyLoader]
-        private void load()
-        {
-            IsConnected.BindValueChanged(connected =>
-            {
-                // clean up local room state on server disconnect.
-                if (!connected.NewValue && Room != null)
-                {
-                    Logger.Log("Connection to multiplayer server was lost.", LoggingTarget.Runtime, LogLevel.Important);
-                    LeaveRoom();
-                }
-            });
-        }
-
-        private readonly TaskChain joinOrLeaveTaskChain = new TaskChain();
-        private CancellationTokenSource? joinCancellationSource;
-
-        /// <summary>
-        /// Joins the <see cref="MultiplayerRoom"/> for a given API <see cref="Room"/>.
-        /// </summary>
-        /// <param name="room">The API <see cref="Room"/>.</param>
-        public async Task JoinRoom(Room room)
-        {
-            var cancellationSource = joinCancellationSource = new CancellationTokenSource();
-
-            await joinOrLeaveTaskChain.Add(async () =>
-            {
-                if (Room != null)
-                    throw new InvalidOperationException("Cannot join a multiplayer room while already in one.");
-
-                Debug.Assert(room.RoomID.Value != null);
-
-                // Join the server-side room.
-                var joinedRoom = await JoinRoom(room.RoomID.Value.Value).ConfigureAwait(false);
-                Debug.Assert(joinedRoom != null);
-
-                // Populate users.
-                Debug.Assert(joinedRoom.Users != null);
-                await Task.WhenAll(joinedRoom.Users.Select(PopulateUser)).ConfigureAwait(false);
-
-                // Update the stored room (must be done on update thread for thread-safety).
-                await scheduleAsync(() =>
-                {
-                    Room = joinedRoom;
-                    apiRoom = room;
-                    foreach (var user in joinedRoom.Users)
-                        updateUserPlayingState(user.UserID, user.State);
-                }, cancellationSource.Token).ConfigureAwait(false);
-
-                // Update room settings.
-                await updateLocalRoomSettings(joinedRoom.Settings, cancellationSource.Token).ConfigureAwait(false);
-            }, cancellationSource.Token).ConfigureAwait(false);
-        }
-
-        /// <summary>
-        /// Joins the <see cref="MultiplayerRoom"/> with a given ID.
-        /// </summary>
-        /// <param name="roomId">The room ID.</param>
-        /// <returns>The joined <see cref="MultiplayerRoom"/>.</returns>
-        protected abstract Task<MultiplayerRoom> JoinRoom(long roomId);
-
-        public Task LeaveRoom()
-        {
-            // The join may have not completed yet, so certain tasks that either update the room or reference the room should be cancelled.
-            // This includes the setting of Room itself along with the initial update of the room settings on join.
-            joinCancellationSource?.Cancel();
-
-            // Leaving rooms is expected to occur instantaneously whilst the operation is finalised in the background.
-            // However a few members need to be reset immediately to prevent other components from entering invalid states whilst the operation hasn't yet completed.
-            // For example, if a room was left and the user immediately pressed the "create room" button, then the user could be taken into the lobby if the value of Room is not reset in time.
-            var scheduledReset = scheduleAsync(() =>
-            {
-                apiRoom = null;
-                Room = null;
-                CurrentMatchPlayingUserIds.Clear();
-
-                RoomUpdated?.Invoke();
-            });
-
-            return joinOrLeaveTaskChain.Add(async () =>
-            {
-                await scheduledReset.ConfigureAwait(false);
-                await LeaveRoomInternal().ConfigureAwait(false);
-            });
-        }
-
-        protected abstract Task LeaveRoomInternal();
-
-        /// <summary>
-        /// Change the current <see cref="MultiplayerRoom"/> settings.
-        /// </summary>
-        /// <remarks>
-        /// A room must be joined for this to have any effect.
-        /// </remarks>
-        /// <param name="name">The new room name, if any.</param>
-        /// <param name="item">The new room playlist item, if any.</param>
-        public Task ChangeSettings(Optional<string> name = default, Optional<PlaylistItem> item = default)
-        {
-            if (Room == null)
-                throw new InvalidOperationException("Must be joined to a match to change settings.");
-
-            // A dummy playlist item filled with the current room settings (except mods).
-            var existingPlaylistItem = new PlaylistItem
-            {
-                Beatmap =
-                {
-                    Value = new BeatmapInfo
-                    {
-                        OnlineBeatmapID = Room.Settings.BeatmapID,
-                        MD5Hash = Room.Settings.BeatmapChecksum
-                    }
-                },
-                RulesetID = Room.Settings.RulesetID
-            };
-
-            return ChangeSettings(new MultiplayerRoomSettings
-            {
-                Name = name.GetOr(Room.Settings.Name),
-                BeatmapID = item.GetOr(existingPlaylistItem).BeatmapID,
-                BeatmapChecksum = item.GetOr(existingPlaylistItem).Beatmap.Value.MD5Hash,
-                RulesetID = item.GetOr(existingPlaylistItem).RulesetID,
-                RequiredMods = item.HasValue ? item.Value.AsNonNull().RequiredMods.Select(m => new APIMod(m)).ToList() : Room.Settings.RequiredMods,
-                AllowedMods = item.HasValue ? item.Value.AsNonNull().AllowedMods.Select(m => new APIMod(m)).ToList() : Room.Settings.AllowedMods,
-            });
-        }
-
-        /// <summary>
-        /// Toggles the <see cref="LocalUser"/>'s ready state.
-        /// </summary>
-        /// <exception cref="InvalidOperationException">If a toggle of ready state is not valid at this time.</exception>
-        public async Task ToggleReady()
-        {
-            var localUser = LocalUser;
-
-            if (localUser == null)
-                return;
-
-            switch (localUser.State)
-            {
-                case MultiplayerUserState.Idle:
-                    await ChangeState(MultiplayerUserState.Ready).ConfigureAwait(false);
-                    return;
-
-                case MultiplayerUserState.Ready:
-                    await ChangeState(MultiplayerUserState.Idle).ConfigureAwait(false);
-                    return;
-
-                default:
-                    throw new InvalidOperationException($"Cannot toggle ready when in {localUser.State}");
-            }
-        }
-
-        /// <summary>
-        /// Toggles the <see cref="LocalUser"/>'s spectating state.
-        /// </summary>
-        /// <exception cref="InvalidOperationException">If a toggle of the spectating state is not valid at this time.</exception>
-        public async Task ToggleSpectate()
-        {
-            var localUser = LocalUser;
-
-            if (localUser == null)
-                return;
-
-            switch (localUser.State)
-            {
-                case MultiplayerUserState.Idle:
-                case MultiplayerUserState.Ready:
-                    await ChangeState(MultiplayerUserState.Spectating).ConfigureAwait(false);
-                    return;
-
-                case MultiplayerUserState.Spectating:
-                    await ChangeState(MultiplayerUserState.Idle).ConfigureAwait(false);
-                    return;
-
-                default:
-                    throw new InvalidOperationException($"Cannot toggle spectate when in {localUser.State}");
-            }
-        }
-
-        public abstract Task TransferHost(int userId);
-
-        public abstract Task ChangeSettings(MultiplayerRoomSettings settings);
-
-        public abstract Task ChangeState(MultiplayerUserState newState);
-
-        public abstract Task ChangeBeatmapAvailability(BeatmapAvailability newBeatmapAvailability);
-
-        /// <summary>
-        /// Change the local user's mods in the currently joined room.
-        /// </summary>
-        /// <param name="newMods">The proposed new mods, excluding any required by the room itself.</param>
-        public Task ChangeUserMods(IEnumerable<Mod> newMods) => ChangeUserMods(newMods.Select(m => new APIMod(m)).ToList());
-
-        public abstract Task ChangeUserMods(IEnumerable<APIMod> newMods);
-
-        public abstract Task StartMatch();
-
-        Task IMultiplayerClient.RoomStateChanged(MultiplayerRoomState state)
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                if (Room == null)
-                    return;
-
-                Debug.Assert(apiRoom != null);
-
-                Room.State = state;
-
-                switch (state)
-                {
-                    case MultiplayerRoomState.Open:
-                        apiRoom.Status.Value = new RoomStatusOpen();
-                        break;
-
-                    case MultiplayerRoomState.Playing:
-                        apiRoom.Status.Value = new RoomStatusPlaying();
-                        break;
-
-                    case MultiplayerRoomState.Closed:
-                        apiRoom.Status.Value = new RoomStatusEnded();
-                        break;
-                }
-
-                RoomUpdated?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        async Task IMultiplayerClient.UserJoined(MultiplayerRoomUser user)
-        {
-            if (Room == null)
-                return;
-
-            await PopulateUser(user).ConfigureAwait(false);
-
-            Scheduler.Add(() =>
-            {
-                if (Room == null)
-                    return;
-
-                // for sanity, ensure that there can be no duplicate users in the room user list.
-                if (Room.Users.Any(existing => existing.UserID == user.UserID))
-                    return;
-
-                Room.Users.Add(user);
-
-                RoomUpdated?.Invoke();
-            }, false);
-        }
-
-        Task IMultiplayerClient.UserLeft(MultiplayerRoomUser user)
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                if (Room == null)
-                    return;
-
-                Room.Users.Remove(user);
-                CurrentMatchPlayingUserIds.Remove(user.UserID);
-
-                RoomUpdated?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        Task IMultiplayerClient.HostChanged(int userId)
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                if (Room == null)
-                    return;
-
-                Debug.Assert(apiRoom != null);
-
-                var user = Room.Users.FirstOrDefault(u => u.UserID == userId);
-
-                Room.Host = user;
-                apiRoom.Host.Value = user?.User;
-
-                RoomUpdated?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        Task IMultiplayerClient.SettingsChanged(MultiplayerRoomSettings newSettings)
-        {
-            updateLocalRoomSettings(newSettings);
-            return Task.CompletedTask;
-        }
-
-        Task IMultiplayerClient.UserStateChanged(int userId, MultiplayerUserState state)
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                if (Room == null)
-                    return;
-
-                Room.Users.Single(u => u.UserID == userId).State = state;
-
-                updateUserPlayingState(userId, state);
-
-                RoomUpdated?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        Task IMultiplayerClient.UserBeatmapAvailabilityChanged(int userId, BeatmapAvailability beatmapAvailability)
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                var user = Room?.Users.SingleOrDefault(u => u.UserID == userId);
-
-                // errors here are not critical - beatmap availability state is mostly for display.
-                if (user == null)
-                    return;
-
-                user.BeatmapAvailability = beatmapAvailability;
-
-                RoomUpdated?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        public Task UserModsChanged(int userId, IEnumerable<APIMod> mods)
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                var user = Room?.Users.SingleOrDefault(u => u.UserID == userId);
-
-                // errors here are not critical - user mods are mostly for display.
-                if (user == null)
-                    return;
-
-                user.Mods = mods;
-
-                RoomUpdated?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        Task IMultiplayerClient.LoadRequested()
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                if (Room == null)
-                    return;
-
-                LoadRequested?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        Task IMultiplayerClient.MatchStarted()
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                if (Room == null)
-                    return;
-
-                MatchStarted?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        Task IMultiplayerClient.ResultsReady()
-        {
-            if (Room == null)
-                return Task.CompletedTask;
-
-            Scheduler.Add(() =>
-            {
-                if (Room == null)
-                    return;
-
-                ResultsReady?.Invoke();
-            }, false);
-
-            return Task.CompletedTask;
-        }
-
-        /// <summary>
-        /// Populates the <see cref="User"/> for a given <see cref="MultiplayerRoomUser"/>.
-        /// </summary>
-        /// <param name="multiplayerUser">The <see cref="MultiplayerRoomUser"/> to populate.</param>
-        protected async Task PopulateUser(MultiplayerRoomUser multiplayerUser) => multiplayerUser.User ??= await userLookupCache.GetUserAsync(multiplayerUser.UserID).ConfigureAwait(false);
-
-        /// <summary>
-        /// Updates the local room settings with the given <see cref="MultiplayerRoomSettings"/>.
-        /// </summary>
-        /// <remarks>
-        /// This updates both the joined <see cref="MultiplayerRoom"/> and the respective API <see cref="Room"/>.
-        /// </remarks>
-        /// <param name="settings">The new <see cref="MultiplayerRoomSettings"/> to update from.</param>
-        /// <param name="cancellationToken">The <see cref="CancellationToken"/> to cancel the update.</param>
-        private Task updateLocalRoomSettings(MultiplayerRoomSettings settings, CancellationToken cancellationToken = default) => scheduleAsync(() =>
-        {
-            if (Room == null)
-                return;
-
-            Debug.Assert(apiRoom != null);
-
-            // Update a few properties of the room instantaneously.
-            Room.Settings = settings;
-            apiRoom.Name.Value = Room.Settings.Name;
-
-            // The current item update is delayed until an online beatmap lookup (below) succeeds.
-            // In-order for the client to not display an outdated beatmap, the current item is forcefully cleared here.
-            CurrentMatchPlayingItem.Value = null;
-
-            RoomUpdated?.Invoke();
-
-            GetOnlineBeatmapSet(settings.BeatmapID, cancellationToken).ContinueWith(set => Schedule(() =>
-            {
-                if (cancellationToken.IsCancellationRequested)
-                    return;
-
-                updatePlaylist(settings, set.Result);
-            }), TaskContinuationOptions.OnlyOnRanToCompletion);
-        }, cancellationToken);
-
-        private void updatePlaylist(MultiplayerRoomSettings settings, BeatmapSetInfo beatmapSet)
-        {
-            if (Room == null || !Room.Settings.Equals(settings))
-                return;
-
-            Debug.Assert(apiRoom != null);
-
-            var beatmap = beatmapSet.Beatmaps.Single(b => b.OnlineBeatmapID == settings.BeatmapID);
-            beatmap.MD5Hash = settings.BeatmapChecksum;
-
-            var ruleset = Rulesets.GetRuleset(settings.RulesetID).CreateInstance();
-            var mods = settings.RequiredMods.Select(m => m.ToMod(ruleset));
-            var allowedMods = settings.AllowedMods.Select(m => m.ToMod(ruleset));
-
-            // Try to retrieve the existing playlist item from the API room.
-            var playlistItem = apiRoom.Playlist.FirstOrDefault(i => i.ID == settings.PlaylistItemId);
-
-            if (playlistItem != null)
-                updateItem(playlistItem);
-            else
-            {
-                // An existing playlist item does not exist, so append a new one.
-                updateItem(playlistItem = new PlaylistItem());
-                apiRoom.Playlist.Add(playlistItem);
-            }
-
-            CurrentMatchPlayingItem.Value = playlistItem;
-
-            void updateItem(PlaylistItem item)
-            {
-                item.ID = settings.PlaylistItemId;
-                item.Beatmap.Value = beatmap;
-                item.Ruleset.Value = ruleset.RulesetInfo;
-                item.RequiredMods.Clear();
-                item.RequiredMods.AddRange(mods);
-                item.AllowedMods.Clear();
-                item.AllowedMods.AddRange(allowedMods);
-            }
-        }
-
-        /// <summary>
-        /// Retrieves a <see cref="BeatmapSetInfo"/> from an online source.
-        /// </summary>
-        /// <param name="beatmapId">The beatmap set ID.</param>
-        /// <param name="cancellationToken">A token to cancel the request.</param>
-        /// <returns>The <see cref="BeatmapSetInfo"/> retrieval task.</returns>
-        protected abstract Task<BeatmapSetInfo> GetOnlineBeatmapSet(int beatmapId, CancellationToken cancellationToken = default);
-
-        /// <summary>
-        /// For the provided user ID, update whether the user is included in <see cref="CurrentMatchPlayingUserIds"/>.
-        /// </summary>
-        /// <param name="userId">The user's ID.</param>
-        /// <param name="state">The new state of the user.</param>
-        private void updateUserPlayingState(int userId, MultiplayerUserState state)
-        {
-            bool wasPlaying = CurrentMatchPlayingUserIds.Contains(userId);
-            bool isPlaying = state >= MultiplayerUserState.WaitingForLoad && state <= MultiplayerUserState.FinishedPlay;
-
-            if (isPlaying == wasPlaying)
-                return;
-
-            if (isPlaying)
-                CurrentMatchPlayingUserIds.Add(userId);
-            else
-                CurrentMatchPlayingUserIds.Remove(userId);
-        }
-
-        private Task scheduleAsync(Action action, CancellationToken cancellationToken = default)
-        {
-            var tcs = new TaskCompletionSource<bool>();
-
-            Scheduler.Add(() =>
-            {
-                if (cancellationToken.IsCancellationRequested)
-                {
-                    tcs.SetCanceled();
-                    return;
-                }
-
-                try
-                {
-                    action();
-                    tcs.SetResult(true);
-                }
-                catch (Exception ex)
-                {
-                    tcs.SetException(ex);
-                }
-            });
-
-            return tcs.Task;
-        }
-    }
-}

osu.Game/Online/Spectator/OnlineSpectatorClient.cs

@@ -0,0 +1,89 @@
+// 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.
+
+#nullable enable
+
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.SignalR.Client;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Game.Online.API;
+
+namespace osu.Game.Online.Spectator
+{
+    public class OnlineSpectatorClient : SpectatorClient
+    {
+        private readonly string endpoint;
+
+        private IHubClientConnector? connector;
+
+        public override IBindable<bool> IsConnected { get; } = new BindableBool();
+
+        private HubConnection? connection => connector?.CurrentConnection;
+
+        public OnlineSpectatorClient(EndpointConfiguration endpoints)
+        {
+            endpoint = endpoints.SpectatorEndpointUrl;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load(IAPIProvider api)
+        {
+            connector = api.GetHubConnector(nameof(SpectatorClient), endpoint);
+
+            if (connector != null)
+            {
+                connector.ConfigureConnection = connection =>
+                {
+                    // until strong typed client support is added, each method must be manually bound
+                    // (see https://github.com/dotnet/aspnetcore/issues/15198)
+                    connection.On<int, SpectatorState>(nameof(ISpectatorClient.UserBeganPlaying), ((ISpectatorClient)this).UserBeganPlaying);
+                    connection.On<int, FrameDataBundle>(nameof(ISpectatorClient.UserSentFrames), ((ISpectatorClient)this).UserSentFrames);
+                    connection.On<int, SpectatorState>(nameof(ISpectatorClient.UserFinishedPlaying), ((ISpectatorClient)this).UserFinishedPlaying);
+                };
+
+                IsConnected.BindTo(connector.IsConnected);
+            }
+        }
+
+        protected override Task BeginPlayingInternal(SpectatorState state)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.SendAsync(nameof(ISpectatorServer.BeginPlaySession), state);
+        }
+
+        protected override Task SendFramesInternal(FrameDataBundle data)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.SendAsync(nameof(ISpectatorServer.SendFrameData), data);
+        }
+
+        protected override Task EndPlayingInternal(SpectatorState state)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.SendAsync(nameof(ISpectatorServer.EndPlaySession), state);
+        }
+
+        protected override Task WatchUserInternal(int userId)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.SendAsync(nameof(ISpectatorServer.StartWatchingUser), userId);
+        }
+
+        protected override Task StopWatchingUserInternal(int userId)
+        {
+            if (!IsConnected.Value)
+                return Task.CompletedTask;
+
+            return connection.SendAsync(nameof(ISpectatorServer.EndWatchingUser), userId);
+        }
+    }
+}

osu.Game/Online/Spectator/SpectatorClient.cs

@@ -1,13 +1,13 @@
 // 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.
 
+#nullable enable
+
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading.Tasks;
-using JetBrains.Annotations;
-using Microsoft.AspNetCore.SignalR.Client;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -23,21 +23,18 @@ using osu.Game.Screens.Play;
 
 namespace osu.Game.Online.Spectator
 {
-    public class SpectatorStreamingClient : Component, ISpectatorClient
+    public abstract class SpectatorClient : Component, ISpectatorClient
     {
         /// <summary>
         /// The maximum milliseconds between frame bundle sends.
         /// </summary>
         public const double TIME_BETWEEN_SENDS = 200;
 
-        private readonly string endpoint;
+        /// <summary>
-
+        /// Whether the <see cref="SpectatorClient"/> is currently connected.
-        [CanBeNull]
+        /// This is NOT thread safe and usage should be scheduled.
-        private IHubClientConnector connector;
+        /// </summary>
-
+        public abstract IBindable<bool> IsConnected { get; }
-        private readonly IBindable<bool> isConnected = new BindableBool();
-
-        private HubConnection connection => connector?.CurrentConnection;
 
         private readonly List<int> watchingUsers = new List<int>();
 
@@ -49,60 +46,42 @@ namespace osu.Game.Online.Spectator
 
         private readonly Dictionary<int, SpectatorState> playingUserStates = new Dictionary<int, SpectatorState>();
 
-        [CanBeNull]
+        private IBeatmap? currentBeatmap;
-        private IBeatmap currentBeatmap;
 
-        [CanBeNull]
+        private Score? currentScore;
-        private Score currentScore;
 
         [Resolved]
-        private IBindable<RulesetInfo> currentRuleset { get; set; }
+        private IBindable<RulesetInfo> currentRuleset { get; set; } = null!;
 
         [Resolved]
-        private IBindable<IReadOnlyList<Mod>> currentMods { get; set; }
+        private IBindable<IReadOnlyList<Mod>> currentMods { get; set; } = null!;
 
         private readonly SpectatorState currentState = new SpectatorState();
 
-        private bool isPlaying;
+        /// <summary>
+        /// Whether the local user is playing.
+        /// </summary>
+        protected bool IsPlaying { get; private set; }
 
         /// <summary>
         /// Called whenever new frames arrive from the server.
         /// </summary>
-        public event Action<int, FrameDataBundle> OnNewFrames;
+        public event Action<int, FrameDataBundle>? OnNewFrames;
 
         /// <summary>
         /// Called whenever a user starts a play session, or immediately if the user is being watched and currently in a play session.
         /// </summary>
-        public event Action<int, SpectatorState> OnUserBeganPlaying;
+        public event Action<int, SpectatorState>? OnUserBeganPlaying;
 
         /// <summary>
         /// Called whenever a user finishes a play session.
         /// </summary>
-        public event Action<int, SpectatorState> OnUserFinishedPlaying;
+        public event Action<int, SpectatorState>? OnUserFinishedPlaying;
-
-        public SpectatorStreamingClient(EndpointConfiguration endpoints)
-        {
-            endpoint = endpoints.SpectatorEndpointUrl;
-        }
 
         [BackgroundDependencyLoader]
-        private void load(IAPIProvider api)
+        private void load()
         {
-            connector = api.GetHubConnector(nameof(SpectatorStreamingClient), endpoint);
+            IsConnected.BindValueChanged(connected =>
-
-            if (connector != null)
-            {
-                connector.ConfigureConnection = connection =>
-                {
-                    // until strong typed client support is added, each method must be manually bound
-                    // (see https://github.com/dotnet/aspnetcore/issues/15198)
-                    connection.On<int, SpectatorState>(nameof(ISpectatorClient.UserBeganPlaying), ((ISpectatorClient)this).UserBeganPlaying);
-                    connection.On<int, FrameDataBundle>(nameof(ISpectatorClient.UserSentFrames), ((ISpectatorClient)this).UserSentFrames);
-                    connection.On<int, SpectatorState>(nameof(ISpectatorClient.UserFinishedPlaying), ((ISpectatorClient)this).UserFinishedPlaying);
-                };
-
-                isConnected.BindTo(connector.IsConnected);
-                isConnected.BindValueChanged(connected =>
             {
                 if (connected.NewValue)
                 {
@@ -120,8 +99,8 @@ namespace osu.Game.Online.Spectator
                         WatchUser(userId);
 
                     // re-send state in case it wasn't received
-                        if (isPlaying)
+                    if (IsPlaying)
-                            beginPlaying();
+                        BeginPlayingInternal(currentState);
                 }
                 else
                 {
@@ -133,7 +112,6 @@ namespace osu.Game.Online.Spectator
                 }
             }, true);
         }
-        }
 
         Task ISpectatorClient.UserBeganPlaying(int userId, SpectatorState state)
         {
@@ -176,10 +154,10 @@ namespace osu.Game.Online.Spectator
 
         public void BeginPlaying(GameplayBeatmap beatmap, Score score)
         {
-            if (isPlaying)
+            if (IsPlaying)
                 throw new InvalidOperationException($"Cannot invoke {nameof(BeginPlaying)} when already playing");
 
-            isPlaying = true;
+            IsPlaying = true;
 
             // transfer state at point of beginning play
             currentState.BeatmapID = beatmap.BeatmapInfo.OnlineBeatmapID;
@@ -189,36 +167,20 @@ namespace osu.Game.Online.Spectator
             currentBeatmap = beatmap.PlayableBeatmap;
             currentScore = score;
 
-            beginPlaying();
+            BeginPlayingInternal(currentState);
         }
 
-        private void beginPlaying()
+        public void SendFrames(FrameDataBundle data) => lastSend = SendFramesInternal(data);
-        {
-            Debug.Assert(isPlaying);
-
-            if (!isConnected.Value) return;
-
-            connection.SendAsync(nameof(ISpectatorServer.BeginPlaySession), currentState);
-        }
-
-        public void SendFrames(FrameDataBundle data)
-        {
-            if (!isConnected.Value) return;
-
-            lastSend = connection.SendAsync(nameof(ISpectatorServer.SendFrameData), data);
-        }
 
         public void EndPlaying()
         {
-            isPlaying = false;
+            IsPlaying = false;
             currentBeatmap = null;
 
-            if (!isConnected.Value) return;
+            EndPlayingInternal(currentState);
-
-            connection.SendAsync(nameof(ISpectatorServer.EndPlaySession), currentState);
         }
 
-        public virtual void WatchUser(int userId)
+        public void WatchUser(int userId)
         {
             lock (userLock)
             {
@@ -226,32 +188,36 @@ namespace osu.Game.Online.Spectator
                     return;
 
                 watchingUsers.Add(userId);
-
-                if (!isConnected.Value)
-                    return;
             }
 
-            connection.SendAsync(nameof(ISpectatorServer.StartWatchingUser), userId);
+            WatchUserInternal(userId);
         }
 
-        public virtual void StopWatchingUser(int userId)
+        public void StopWatchingUser(int userId)
         {
             lock (userLock)
             {
                 watchingUsers.Remove(userId);
-
-                if (!isConnected.Value)
-                    return;
             }
 
-            connection.SendAsync(nameof(ISpectatorServer.EndWatchingUser), userId);
+            StopWatchingUserInternal(userId);
         }
 
+        protected abstract Task BeginPlayingInternal(SpectatorState state);
+
+        protected abstract Task SendFramesInternal(FrameDataBundle data);
+
+        protected abstract Task EndPlayingInternal(SpectatorState state);
+
+        protected abstract Task WatchUserInternal(int userId);
+
+        protected abstract Task StopWatchingUserInternal(int userId);
+
         private readonly Queue<LegacyReplayFrame> pendingFrames = new Queue<LegacyReplayFrame>();
 
         private double lastSendTime;
 
-        private Task lastSend;
+        private Task? lastSend;
 
         private const int max_pending_frames = 30;
 

osu.Game/OsuGameBase.cs

@@ -85,8 +85,8 @@ namespace osu.Game
 
         protected IAPIProvider API;
 
-        private SpectatorStreamingClient spectatorStreaming;
+        private SpectatorClient spectatorClient;
-        private StatefulMultiplayerClient multiplayerClient;
+        private MultiplayerClient multiplayerClient;
 
         protected MenuCursorContainer MenuCursorContainer;
 
@@ -240,8 +240,8 @@ namespace osu.Game
 
             dependencies.CacheAs(API ??= new APIAccess(LocalConfig, endpoints, VersionHash));
 
-            dependencies.CacheAs(spectatorStreaming = new SpectatorStreamingClient(endpoints));
+            dependencies.CacheAs(spectatorClient = new OnlineSpectatorClient(endpoints));
-            dependencies.CacheAs(multiplayerClient = new MultiplayerClient(endpoints));
+            dependencies.CacheAs(multiplayerClient = new OnlineMultiplayerClient(endpoints));
 
             var defaultBeatmap = new DummyWorkingBeatmap(Audio, Textures);
 
@@ -313,7 +313,7 @@ namespace osu.Game
             // add api components to hierarchy.
             if (API is APIAccess apiAccess)
                 AddInternal(apiAccess);
-            AddInternal(spectatorStreaming);
+            AddInternal(spectatorClient);
             AddInternal(multiplayerClient);
 
             AddInternal(RulesetConfigCache);

osu.Game/Overlays/AccountCreation/ScreenWarning.cs

@@ -23,14 +23,17 @@ namespace osu.Game.Overlays.AccountCreation
         private OsuTextFlowContainer multiAccountExplanationText;
         private LinkFlowContainer furtherAssistance;
 
-        [Resolved(CanBeNull = true)]
+        [Resolved(canBeNull: true)]
         private IAPIProvider api { get; set; }
 
+        [Resolved(canBeNull: true)]
+        private OsuGame game { get; set; }
+
         private const string help_centre_url = "/help/wiki/Help_Centre#login";
 
         public override void OnEntering(IScreen last)
         {
-            if (string.IsNullOrEmpty(api?.ProvidedUsername))
+            if (string.IsNullOrEmpty(api?.ProvidedUsername) || game?.UseDevelopmentServer == true)
             {
                 this.FadeOut();
                 this.Push(new ScreenEntry());
@@ -41,7 +44,7 @@ namespace osu.Game.Overlays.AccountCreation
         }
 
         [BackgroundDependencyLoader(true)]
-        private void load(OsuColour colours, OsuGame game, TextureStore textures)
+        private void load(OsuColour colours, TextureStore textures)
         {
             if (string.IsNullOrEmpty(api?.ProvidedUsername))
                 return;

osu.Game/Overlays/Dashboard/CurrentlyPlayingDisplay.cs

@@ -25,7 +25,7 @@ namespace osu.Game.Overlays.Dashboard
         private FillFlowContainer<PlayingUserPanel> userFlow;
 
         [Resolved]
-        private SpectatorStreamingClient spectatorStreaming { get; set; }
+        private SpectatorClient spectatorClient { get; set; }
 
         [BackgroundDependencyLoader]
         private void load()
@@ -52,7 +52,7 @@ namespace osu.Game.Overlays.Dashboard
         {
             base.LoadComplete();
 
-            playingUsers.BindTo(spectatorStreaming.PlayingUsers);
+            playingUsers.BindTo(spectatorClient.PlayingUsers);
             playingUsers.BindCollectionChanged(onUsersChanged, true);
         }
 

osu.Game/Overlays/Settings/Sections/Gameplay/GeneralSettings.cs

@@ -73,11 +73,6 @@ namespace osu.Game.Overlays.Settings.Sections.Gameplay
                     LabelText = "Always play first combo break sound",
                     Current = config.GetBindable<bool>(OsuSetting.AlwaysPlayFirstComboBreak)
                 },
-                new SettingsEnumDropdown<ScoreMeterType>
-                {
-                    LabelText = "Score meter type",
-                    Current = config.GetBindable<ScoreMeterType>(OsuSetting.ScoreMeter)
-                },
                 new SettingsEnumDropdown<ScoringMode>
                 {
                     LabelText = "Score display mode",

osu.Game/Rulesets/Edit/PlacementBlueprint.cs

@@ -36,7 +36,8 @@ namespace osu.Game.Rulesets.Edit
         [Resolved(canBeNull: true)]
         protected EditorClock EditorClock { get; private set; }
 
-        private readonly IBindable<WorkingBeatmap> beatmap = new Bindable<WorkingBeatmap>();
+        [Resolved]
+        private EditorBeatmap beatmap { get; set; }
 
         private Bindable<double> startTimeBindable;
 
@@ -58,10 +59,8 @@ namespace osu.Game.Rulesets.Edit
         }
 
         [BackgroundDependencyLoader]
-        private void load(IBindable<WorkingBeatmap> beatmap)
+        private void load()
         {
-            this.beatmap.BindTo(beatmap);
-
             startTimeBindable = HitObject.StartTimeBindable.GetBoundCopy();
             startTimeBindable.BindValueChanged(_ => ApplyDefaultsToHitObject(), true);
         }
@@ -113,7 +112,7 @@ namespace osu.Game.Rulesets.Edit
         /// Invokes <see cref="Objects.HitObject.ApplyDefaults(ControlPointInfo,BeatmapDifficulty, CancellationToken)"/>,
         /// refreshing <see cref="Objects.HitObject.NestedHitObjects"/> and parameters for the <see cref="HitObject"/>.
         /// </summary>
-        protected void ApplyDefaultsToHitObject() => HitObject.ApplyDefaults(beatmap.Value.Beatmap.ControlPointInfo, beatmap.Value.Beatmap.BeatmapInfo.BaseDifficulty);
+        protected void ApplyDefaultsToHitObject() => HitObject.ApplyDefaults(beatmap.ControlPointInfo, beatmap.BeatmapInfo.BaseDifficulty);
 
         public override bool ReceivePositionalInputAt(Vector2 screenSpacePos) => Parent?.ReceivePositionalInputAt(screenSpacePos) ?? false;
 

osu.Game/Rulesets/UI/ReplayRecorder.cs

@@ -29,7 +29,7 @@ namespace osu.Game.Rulesets.UI
         public int RecordFrameRate = 60;
 
         [Resolved(canBeNull: true)]
-        private SpectatorStreamingClient spectatorStreaming { get; set; }
+        private SpectatorClient spectatorClient { get; set; }
 
         [Resolved]
         private GameplayBeatmap gameplayBeatmap { get; set; }
@@ -49,13 +49,13 @@ namespace osu.Game.Rulesets.UI
 
             inputManager = GetContainingInputManager();
 
-            spectatorStreaming?.BeginPlaying(gameplayBeatmap, target);
+            spectatorClient?.BeginPlaying(gameplayBeatmap, target);
         }
 
         protected override void Dispose(bool isDisposing)
         {
             base.Dispose(isDisposing);
-            spectatorStreaming?.EndPlaying();
+            spectatorClient?.EndPlaying();
         }
 
         protected override void Update()
@@ -98,7 +98,7 @@ namespace osu.Game.Rulesets.UI
             {
                 target.Replay.Frames.Add(frame);
 
-                spectatorStreaming?.HandleFrame(frame);
+                spectatorClient?.HandleFrame(frame);
             }
         }
 

osu.Game/Screens/Edit/Compose/Components/EditorSelectionHandler.cs

@@ -168,13 +168,13 @@ namespace osu.Game.Screens.Edit.Compose.Components
         {
             if (SelectedBlueprints.All(b => b.Item is IHasComboInformation))
             {
-                yield return new TernaryStateMenuItem("New combo") { State = { BindTarget = SelectionNewComboState } };
+                yield return new TernaryStateToggleMenuItem("New combo") { State = { BindTarget = SelectionNewComboState } };
             }
 
             yield return new OsuMenuItem("Sound")
             {
                 Items = SelectionSampleStates.Select(kvp =>
-                    new TernaryStateMenuItem(kvp.Value.Description) { State = { BindTarget = kvp.Value } }).ToArray()
+                    new TernaryStateToggleMenuItem(kvp.Value.Description) { State = { BindTarget = kvp.Value } }).ToArray()
             };
         }
 

osu.Game/Screens/OnlinePlay/Multiplayer/CreateMultiplayerMatchButton.cs

@@ -14,7 +14,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         private IBindable<bool> operationInProgress;
 
         [Resolved]
-        private StatefulMultiplayerClient multiplayerClient { get; set; }
+        private MultiplayerClient multiplayerClient { get; set; }
 
         [Resolved]
         private OngoingOperationTracker ongoingOperationTracker { get; set; }

osu.Game/Screens/OnlinePlay/Multiplayer/Match/MultiplayerMatchSettingsOverlay.cs

@@ -59,7 +59,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Match
             private IRoomManager manager { get; set; }
 
             [Resolved]
-            private StatefulMultiplayerClient client { get; set; }
+            private MultiplayerClient client { get; set; }
 
             [Resolved]
             private Bindable<Room> currentRoom { get; set; }

osu.Game/Screens/OnlinePlay/Multiplayer/Multiplayer.cs

@@ -15,7 +15,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
     public class Multiplayer : OnlinePlayScreen
     {
         [Resolved]
-        private StatefulMultiplayerClient client { get; set; }
+        private MultiplayerClient client { get; set; }
 
         public override void OnResuming(IScreen last)
         {

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerLoungeSubScreen.cs

@@ -18,7 +18,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         protected override RoomSubScreen CreateRoomSubScreen(Room room) => new MultiplayerMatchSubScreen(room);
 
         [Resolved]
-        private StatefulMultiplayerClient client { get; set; }
+        private MultiplayerClient client { get; set; }
 
         public override void Open(Room room)
         {

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSongSelect.cs

@@ -17,7 +17,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
     public class MultiplayerMatchSongSelect : OnlinePlaySongSelect
     {
         [Resolved]
-        private StatefulMultiplayerClient client { get; set; }
+        private MultiplayerClient client { get; set; }
 
         private LoadingLayer loadingLayer;
 

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerMatchSubScreen.cs

@@ -43,7 +43,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         public override string ShortTitle => "room";
 
         [Resolved]
-        private StatefulMultiplayerClient client { get; set; }
+        private MultiplayerClient client { get; set; }
 
         [Resolved]
         private OngoingOperationTracker ongoingOperationTracker { get; set; }

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerPlayer.cs

@@ -26,7 +26,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         protected override bool CheckModsAllowFailure() => false;
 
         [Resolved]
-        private StatefulMultiplayerClient client { get; set; }
+        private MultiplayerClient client { get; set; }
 
         private IBindable<bool> isConnected;
 

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerRoomComposite.cs

@@ -13,7 +13,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
         protected MultiplayerRoom Room => Client.Room;
 
         [Resolved]
-        protected StatefulMultiplayerClient Client { get; private set; }
+        protected MultiplayerClient Client { get; private set; }
 
         protected override void LoadComplete()
         {

osu.Game/Screens/OnlinePlay/Multiplayer/MultiplayerRoomManager.cs

@@ -19,7 +19,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer
     public class MultiplayerRoomManager : RoomManager
     {
         [Resolved]
-        private StatefulMultiplayerClient multiplayerClient { get; set; }
+        private MultiplayerClient multiplayerClient { get; set; }
 
         public readonly Bindable<double> TimeBetweenListingPolls = new Bindable<double>();
         public readonly Bindable<double> TimeBetweenSelectionPolls = new Bindable<double>();

osu.Game/Screens/OnlinePlay/Multiplayer/Participants/ParticipantsListHeader.cs

@@ -10,7 +10,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Participants
     public class ParticipantsListHeader : OverlinedHeader
     {
         [Resolved]
-        private StatefulMultiplayerClient client { get; set; }
+        private MultiplayerClient client { get; set; }
 
         public ParticipantsListHeader()
             : base("Participants")

osu.Game/Screens/OnlinePlay/Multiplayer/Spectate/MultiSpectatorScreen.cs

@@ -28,10 +28,10 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Spectate
         public bool AllPlayersLoaded => instances.All(p => p?.PlayerLoaded == true);
 
         [Resolved]
-        private SpectatorStreamingClient spectatorClient { get; set; }
+        private SpectatorClient spectatorClient { get; set; }
 
         [Resolved]
-        private StatefulMultiplayerClient multiplayerClient { get; set; }
+        private MultiplayerClient multiplayerClient { get; set; }
 
         private readonly PlayerArea[] instances;
         private MasterGameplayClockContainer masterClockContainer;

osu.Game/Screens/Play/HUD/HitErrorDisplay.cs

@@ -1,127 +0,0 @@
-// 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 osu.Framework.Allocation;
-using osu.Framework.Bindables;
-using osu.Framework.Extensions.IEnumerableExtensions;
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Game.Configuration;
-using osu.Game.Rulesets.Scoring;
-using osu.Game.Screens.Play.HUD.HitErrorMeters;
-
-namespace osu.Game.Screens.Play.HUD
-{
-    public class HitErrorDisplay : Container<HitErrorMeter>
-    {
-        private const int fade_duration = 200;
-        private const int margin = 10;
-
-        private readonly Bindable<ScoreMeterType> type = new Bindable<ScoreMeterType>();
-
-        private readonly HitWindows hitWindows;
-
-        public HitErrorDisplay(HitWindows hitWindows)
-        {
-            this.hitWindows = hitWindows;
-
-            RelativeSizeAxes = Axes.Both;
-        }
-
-        [BackgroundDependencyLoader]
-        private void load(OsuConfigManager config)
-        {
-            config.BindWith(OsuSetting.ScoreMeter, type);
-        }
-
-        protected override void LoadComplete()
-        {
-            base.LoadComplete();
-            type.BindValueChanged(typeChanged, true);
-        }
-
-        private void typeChanged(ValueChangedEvent<ScoreMeterType> type)
-        {
-            Children.ForEach(c => c.FadeOut(fade_duration, Easing.OutQuint));
-
-            if (hitWindows == null)
-                return;
-
-            switch (type.NewValue)
-            {
-                case ScoreMeterType.HitErrorBoth:
-                    createBar(Anchor.CentreLeft);
-                    createBar(Anchor.CentreRight);
-                    break;
-
-                case ScoreMeterType.HitErrorLeft:
-                    createBar(Anchor.CentreLeft);
-                    break;
-
-                case ScoreMeterType.HitErrorRight:
-                    createBar(Anchor.CentreRight);
-                    break;
-
-                case ScoreMeterType.HitErrorBottom:
-                    createBar(Anchor.BottomCentre);
-                    break;
-
-                case ScoreMeterType.ColourBoth:
-                    createColour(Anchor.CentreLeft);
-                    createColour(Anchor.CentreRight);
-                    break;
-
-                case ScoreMeterType.ColourLeft:
-                    createColour(Anchor.CentreLeft);
-                    break;
-
-                case ScoreMeterType.ColourRight:
-                    createColour(Anchor.CentreRight);
-                    break;
-
-                case ScoreMeterType.ColourBottom:
-                    createColour(Anchor.BottomCentre);
-                    break;
-            }
-        }
-
-        private void createBar(Anchor anchor)
-        {
-            bool rightAligned = (anchor & Anchor.x2) > 0;
-            bool bottomAligned = (anchor & Anchor.y2) > 0;
-
-            var display = new BarHitErrorMeter(hitWindows, rightAligned)
-            {
-                Margin = new MarginPadding(margin),
-                Anchor = anchor,
-                Origin = bottomAligned ? Anchor.CentreLeft : anchor,
-                Alpha = 0,
-                Rotation = bottomAligned ? 270 : 0
-            };
-
-            completeDisplayLoading(display);
-        }
-
-        private void createColour(Anchor anchor)
-        {
-            bool bottomAligned = (anchor & Anchor.y2) > 0;
-
-            var display = new ColourHitErrorMeter(hitWindows)
-            {
-                Margin = new MarginPadding(margin),
-                Anchor = anchor,
-                Origin = bottomAligned ? Anchor.CentreLeft : anchor,
-                Alpha = 0,
-                Rotation = bottomAligned ? 270 : 0
-            };
-
-            completeDisplayLoading(display);
-        }
-
-        private void completeDisplayLoading(HitErrorMeter display)
-        {
-            Add(display);
-            display.FadeInFromZero(fade_duration, Easing.OutQuint);
-        }
-    }
-}

osu.Game/Screens/Play/HUD/HitErrorMeters/BarHitErrorMeter.cs

@@ -20,8 +20,6 @@ namespace osu.Game.Screens.Play.HUD.HitErrorMeters
 {
     public class BarHitErrorMeter : HitErrorMeter
     {
-        private readonly Anchor alignment;
-
         private const int arrow_move_duration = 400;
 
         private const int judgement_line_width = 6;
@@ -43,11 +41,8 @@ namespace osu.Game.Screens.Play.HUD.HitErrorMeters
 
         private double maxHitWindow;
 
-        public BarHitErrorMeter(HitWindows hitWindows, bool rightAligned = false)
+        public BarHitErrorMeter()
-            : base(hitWindows)
         {
-            alignment = rightAligned ? Anchor.x0 : Anchor.x2;
-
             AutoSizeAxes = Axes.Both;
         }
 
@@ -63,33 +58,42 @@ namespace osu.Game.Screens.Play.HUD.HitErrorMeters
                 Margin = new MarginPadding(2),
                 Children = new Drawable[]
                 {
-                    judgementsContainer = new Container
+                    new Container
                     {
-                        Anchor = Anchor.y1 | alignment,
+                        Anchor = Anchor.CentreLeft,
-                        Origin = Anchor.y1 | alignment,
+                        Origin = Anchor.CentreLeft,
-                        Width = judgement_line_width,
+                        Width = chevron_size,
                         RelativeSizeAxes = Axes.Y,
+                        Child = arrow = new SpriteIcon
+                        {
+                            Anchor = Anchor.TopCentre,
+                            Origin = Anchor.Centre,
+                            RelativePositionAxes = Axes.Y,
+                            Y = 0.5f,
+                            Icon = FontAwesome.Solid.ChevronRight,
+                            Size = new Vector2(chevron_size),
+                        }
                     },
                     colourBars = new Container
                     {
                         Width = bar_width,
                         RelativeSizeAxes = Axes.Y,
-                        Anchor = Anchor.y1 | alignment,
+                        Anchor = Anchor.CentreLeft,
-                        Origin = Anchor.y1 | alignment,
+                        Origin = Anchor.CentreLeft,
                         Children = new Drawable[]
                         {
                             colourBarsEarly = new Container
                             {
-                                Anchor = Anchor.y1 | alignment,
+                                Anchor = Anchor.CentreLeft,
-                                Origin = alignment,
+                                Origin = Anchor.TopRight,
                                 RelativeSizeAxes = Axes.Both,
                                 Height = 0.5f,
                                 Scale = new Vector2(1, -1),
                             },
                             colourBarsLate = new Container
                             {
-                                Anchor = Anchor.y1 | alignment,
+                                Anchor = Anchor.CentreLeft,
-                                Origin = alignment,
+                                Origin = Anchor.TopRight,
                                 RelativeSizeAxes = Axes.Both,
                                 Height = 0.5f,
                             },
@@ -115,21 +119,12 @@ namespace osu.Game.Screens.Play.HUD.HitErrorMeters
                             }
                         }
                     },
-                    new Container
+                    judgementsContainer = new Container
                     {
-                        Anchor = Anchor.y1 | alignment,
+                        Anchor = Anchor.CentreLeft,
-                        Origin = Anchor.y1 | alignment,
+                        Origin = Anchor.CentreLeft,
-                        Width = chevron_size,
+                        Width = judgement_line_width,
                         RelativeSizeAxes = Axes.Y,
-                        Child = arrow = new SpriteIcon
-                        {
-                            Anchor = Anchor.TopCentre,
-                            Origin = Anchor.Centre,
-                            RelativePositionAxes = Axes.Y,
-                            Y = 0.5f,
-                            Icon = alignment == Anchor.x2 ? FontAwesome.Solid.ChevronRight : FontAwesome.Solid.ChevronLeft,
-                            Size = new Vector2(chevron_size),
-                        }
                     },
                 }
             };
@@ -152,19 +147,22 @@ namespace osu.Game.Screens.Play.HUD.HitErrorMeters
         {
             var windows = HitWindows.GetAllAvailableWindows().ToArray();
 
-            maxHitWindow = windows.First().length;
+            // max to avoid div-by-zero.
+            maxHitWindow = Math.Max(1, windows.First().length);
 
             for (var i = 0; i < windows.Length; i++)
             {
                 var (result, length) = windows[i];
 
-                colourBarsEarly.Add(createColourBar(result, (float)(length / maxHitWindow), i == 0));
+                var hitWindow = (float)(length / maxHitWindow);
-                colourBarsLate.Add(createColourBar(result, (float)(length / maxHitWindow), i == 0));
+
+                colourBarsEarly.Add(createColourBar(result, hitWindow, i == 0));
+                colourBarsLate.Add(createColourBar(result, hitWindow, i == 0));
             }
 
             // a little nub to mark the centre point.
             var centre = createColourBar(windows.Last().result, 0.01f);
-            centre.Anchor = centre.Origin = Anchor.y1 | (alignment == Anchor.x2 ? Anchor.x0 : Anchor.x2);
+            centre.Anchor = centre.Origin = Anchor.CentreLeft;
             centre.Width = 2.5f;
             colourBars.Add(centre);
 
@@ -236,8 +234,7 @@ namespace osu.Game.Screens.Play.HUD.HitErrorMeters
             judgementsContainer.Add(new JudgementLine
             {
                 Y = getRelativeJudgementPosition(judgement.TimeOffset),
-                Anchor = alignment == Anchor.x2 ? Anchor.x0 : Anchor.x2,
+                Origin = Anchor.CentreLeft,
-                Origin = Anchor.y1 | (alignment == Anchor.x2 ? Anchor.x0 : Anchor.x2),
             });
 
             arrow.MoveToY(

osu.Game/Screens/Play/HUD/HitErrorMeters/ColourHitErrorMeter.cs

@@ -7,7 +7,6 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Shapes;
 using osu.Game.Rulesets.Judgements;
-using osu.Game.Rulesets.Scoring;
 using osuTK;
 using osuTK.Graphics;
 
@@ -19,8 +18,7 @@ namespace osu.Game.Screens.Play.HUD.HitErrorMeters
 
         private readonly JudgementFlow judgementsFlow;
 
-        public ColourHitErrorMeter(HitWindows hitWindows)
+        public ColourHitErrorMeter()
-            : base(hitWindows)
         {
             AutoSizeAxes = Axes.Both;
             InternalChild = judgementsFlow = new JudgementFlow();

osu.Game/Screens/Play/HUD/HitErrorMeters/HitErrorMeter.cs

@@ -6,13 +6,15 @@ using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics;
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Scoring;
+using osu.Game.Rulesets.UI;
+using osu.Game.Skinning;
 using osuTK.Graphics;
 
 namespace osu.Game.Screens.Play.HUD.HitErrorMeters
 {
-    public abstract class HitErrorMeter : CompositeDrawable
+    public abstract class HitErrorMeter : CompositeDrawable, ISkinnableDrawable
     {
-        protected readonly HitWindows HitWindows;
+        protected HitWindows HitWindows { get; private set; }
 
         [Resolved]
         private ScoreProcessor processor { get; set; }
@@ -20,9 +22,10 @@ namespace osu.Game.Screens.Play.HUD.HitErrorMeters
         [Resolved]
         private OsuColour colours { get; set; }
 
-        protected HitErrorMeter(HitWindows hitWindows)
+        [BackgroundDependencyLoader(true)]
+        private void load(DrawableRuleset drawableRuleset)
         {
-            HitWindows = hitWindows;
+            HitWindows = drawableRuleset?.FirstAvailableHitWindows ?? HitWindows.Empty;
         }
 
         protected override void LoadComplete()

osu.Game/Screens/Play/HUD/MultiplayerGameplayLeaderboard.cs

@@ -22,10 +22,10 @@ namespace osu.Game.Screens.Play.HUD
         protected readonly Dictionary<int, TrackedUserData> UserScores = new Dictionary<int, TrackedUserData>();
 
         [Resolved]
-        private SpectatorStreamingClient streamingClient { get; set; }
+        private SpectatorClient spectatorClient { get; set; }
 
         [Resolved]
-        private StatefulMultiplayerClient multiplayerClient { get; set; }
+        private MultiplayerClient multiplayerClient { get; set; }
 
         [Resolved]
         private UserLookupCache userLookupCache { get; set; }
@@ -55,7 +55,7 @@ namespace osu.Game.Screens.Play.HUD
 
             foreach (var userId in playingUsers)
             {
-                streamingClient.WatchUser(userId);
+                spectatorClient.WatchUser(userId);
 
                 // probably won't be required in the final implementation.
                 var resolvedUser = userLookupCache.GetUserAsync(userId).Result;
@@ -88,7 +88,7 @@ namespace osu.Game.Screens.Play.HUD
             playingUsers.BindCollectionChanged(usersChanged);
 
             // this leaderboard should be guaranteed to be completely loaded before the gameplay starts (is a prerequisite in MultiplayerPlayer).
-            streamingClient.OnNewFrames += handleIncomingFrames;
+            spectatorClient.OnNewFrames += handleIncomingFrames;
         }
 
         private void usersChanged(object sender, NotifyCollectionChangedEventArgs e)
@@ -98,7 +98,7 @@ namespace osu.Game.Screens.Play.HUD
                 case NotifyCollectionChangedAction.Remove:
                     foreach (var userId in e.OldItems.OfType<int>())
                     {
-                        streamingClient.StopWatchingUser(userId);
+                        spectatorClient.StopWatchingUser(userId);
 
                         if (UserScores.TryGetValue(userId, out var trackedData))
                             trackedData.MarkUserQuit();
@@ -123,14 +123,14 @@ namespace osu.Game.Screens.Play.HUD
         {
             base.Dispose(isDisposing);
 
-            if (streamingClient != null)
+            if (spectatorClient != null)
             {
                 foreach (var user in playingUsers)
                 {
-                    streamingClient.StopWatchingUser(user);
+                    spectatorClient.StopWatchingUser(user);
                 }
 
-                streamingClient.OnNewFrames -= handleIncomingFrames;
+                spectatorClient.OnNewFrames -= handleIncomingFrames;
             }
         }
 

osu.Game/Screens/Play/HUDOverlay.cs

@@ -87,22 +87,10 @@ namespace osu.Game.Screens.Play
                 visibilityContainer = new Container
                 {
                     RelativeSizeAxes = Axes.Both,
-                    Children = new Drawable[]
+                    Child = mainComponents = new SkinnableTargetContainer(SkinnableTarget.MainHUDComponents)
-                    {
-                        mainComponents = new SkinnableTargetContainer(SkinnableTarget.MainHUDComponents)
                     {
                         RelativeSizeAxes = Axes.Both,
                     },
-                        new Container
-                        {
-                            RelativeSizeAxes = Axes.Both,
-                            Children = new Drawable[]
-                            {
-                                // still need to be migrated; a bit more involved.
-                                new HitErrorDisplay(this.drawableRuleset?.FirstAvailableHitWindows),
-                            }
-                        },
-                    }
                 },
                 topRightElements = new FillFlowContainer
                 {

osu.Game/Screens/Play/SongProgress.cs

@@ -20,10 +20,14 @@ namespace osu.Game.Screens.Play
 {
     public class SongProgress : OverlayContainer, ISkinnableDrawable
     {
-        private const int info_height = 20;
+        public const float MAX_HEIGHT = info_height + bottom_bar_height + graph_height + handle_height;
-        private const int bottom_bar_height = 5;
+
+        private const float info_height = 20;
+        private const float bottom_bar_height = 5;
         private const float graph_height = SquareGraph.Column.WIDTH * 6;
-        private static readonly Vector2 handle_size = new Vector2(10, 18);
+        private const float handle_height = 18;
+
+        private static readonly Vector2 handle_size = new Vector2(10, handle_height);
 
         private const float transition_duration = 200;
 

osu.Game/Screens/Play/SpectatorPlayer.cs

@@ -31,12 +31,12 @@ namespace osu.Game.Screens.Play
         }
 
         [Resolved]
-        private SpectatorStreamingClient spectatorStreaming { get; set; }
+        private SpectatorClient spectatorClient { get; set; }
 
         [BackgroundDependencyLoader]
         private void load()
         {
-            spectatorStreaming.OnUserBeganPlaying += userBeganPlaying;
+            spectatorClient.OnUserBeganPlaying += userBeganPlaying;
 
             AddInternal(new OsuSpriteText
             {
@@ -66,7 +66,7 @@ namespace osu.Game.Screens.Play
 
         public override bool OnExiting(IScreen next)
         {
-            spectatorStreaming.OnUserBeganPlaying -= userBeganPlaying;
+            spectatorClient.OnUserBeganPlaying -= userBeganPlaying;
             return base.OnExiting(next);
         }
 
@@ -84,8 +84,8 @@ namespace osu.Game.Screens.Play
         {
             base.Dispose(isDisposing);
 
-            if (spectatorStreaming != null)
+            if (spectatorClient != null)
-                spectatorStreaming.OnUserBeganPlaying -= userBeganPlaying;
+                spectatorClient.OnUserBeganPlaying -= userBeganPlaying;
         }
     }
 }

osu.Game/Screens/Play/SpectatorResultsScreen.cs

@@ -17,12 +17,12 @@ namespace osu.Game.Screens.Play
         }
 
         [Resolved]
-        private SpectatorStreamingClient spectatorStreaming { get; set; }
+        private SpectatorClient spectatorClient { get; set; }
 
         [BackgroundDependencyLoader]
         private void load()
         {
-            spectatorStreaming.OnUserBeganPlaying += userBeganPlaying;
+            spectatorClient.OnUserBeganPlaying += userBeganPlaying;
         }
 
         private void userBeganPlaying(int userId, SpectatorState state)
@@ -40,8 +40,8 @@ namespace osu.Game.Screens.Play
         {
             base.Dispose(isDisposing);
 
-            if (spectatorStreaming != null)
+            if (spectatorClient != null)
-                spectatorStreaming.OnUserBeganPlaying -= userBeganPlaying;
+                spectatorClient.OnUserBeganPlaying -= userBeganPlaying;
         }
     }
 }

osu.Game/Screens/Select/Carousel/DrawableCarouselBeatmapSet.cs

@@ -250,7 +250,7 @@ namespace osu.Game.Screens.Select.Carousel
             else
                 state = TernaryState.False;
 
-            return new TernaryStateMenuItem(collection.Name.Value, MenuItemType.Standard, s =>
+            return new TernaryStateToggleMenuItem(collection.Name.Value, MenuItemType.Standard, s =>
             {
                 foreach (var b in beatmapSet.Beatmaps)
                 {

osu.Game/Screens/Spectate/SpectatorScreen.cs

@@ -37,7 +37,7 @@ namespace osu.Game.Screens.Spectate
         private RulesetStore rulesets { get; set; }
 
         [Resolved]
-        private SpectatorStreamingClient spectatorClient { get; set; }
+        private SpectatorClient spectatorClient { get; set; }
 
         [Resolved]
         private UserLookupCache userLookupCache { get; set; }

osu.Game/Skinning/DefaultSkin.cs

@@ -14,6 +14,7 @@ using osu.Game.Extensions;
 using osu.Game.IO;
 using osu.Game.Screens.Play;
 using osu.Game.Screens.Play.HUD;
+using osu.Game.Screens.Play.HUD.HitErrorMeters;
 using osuTK;
 using osuTK.Graphics;
 
@@ -78,6 +79,24 @@ namespace osu.Game.Skinning
                                         combo.Position = new Vector2(accuracy.ScreenSpaceDeltaToParentSpace(score.ScreenSpaceDrawQuad.Size).X / 2 + horizontal_padding, vertical_offset + 5);
                                         combo.Anchor = Anchor.TopCentre;
                                     }
+
+                                    var hitError = container.OfType<HitErrorMeter>().FirstOrDefault();
+
+                                    if (hitError != null)
+                                    {
+                                        hitError.Anchor = Anchor.CentreLeft;
+                                        hitError.Origin = Anchor.CentreLeft;
+                                    }
+
+                                    var hitError2 = container.OfType<HitErrorMeter>().LastOrDefault();
+
+                                    if (hitError2 != null)
+                                    {
+                                        hitError2.Anchor = Anchor.CentreRight;
+                                        hitError2.Scale = new Vector2(-1, 1);
+                                        // origin flipped to match scale above.
+                                        hitError2.Origin = Anchor.CentreLeft;
+                                    }
                                 }
                             })
                             {
@@ -88,6 +107,8 @@ namespace osu.Game.Skinning
                                     GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.AccuracyCounter)),
                                     GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.HealthDisplay)),
                                     GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.SongProgress)),
+                                    GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.BarHitErrorMeter)),
+                                    GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.BarHitErrorMeter)),
                                 }
                             };
 
@@ -114,6 +135,12 @@ namespace osu.Game.Skinning
 
                         case HUDSkinComponents.SongProgress:
                             return new SongProgress();
+
+                        case HUDSkinComponents.BarHitErrorMeter:
+                            return new BarHitErrorMeter();
+
+                        case HUDSkinComponents.ColourHitErrorMeter:
+                            return new ColourHitErrorMeter();
                     }
 
                     break;

osu.Game/Skinning/Editor/SkinEditor.cs

@@ -19,7 +19,7 @@ using osuTK;
 namespace osu.Game.Skinning.Editor
 {
     [Cached(typeof(SkinEditor))]
-    public class SkinEditor : FocusedOverlayContainer
+    public class SkinEditor : VisibilityContainer
     {
         public const double TRANSITION_DURATION = 500;
 

osu.Game/Skinning/Editor/SkinEditorOverlay.cs

@@ -65,8 +65,6 @@ namespace osu.Game.Skinning.Editor
             if (visibility.NewValue == Visibility.Visible)
             {
                 target.Masking = true;
-                target.BorderThickness = 5;
-                target.BorderColour = colours.Yellow;
                 target.AllowScaling = false;
                 target.RelativePositionAxes = Axes.Both;
 
@@ -75,7 +73,6 @@ namespace osu.Game.Skinning.Editor
             }
             else
             {
-                target.BorderThickness = 0;
                 target.AllowScaling = true;
 
                 target.ScaleTo(1, SkinEditor.TRANSITION_DURATION, Easing.OutQuint).OnComplete(_ => target.Masking = false);

osu.Game/Skinning/Editor/SkinSelectionHandler.cs

@@ -100,7 +100,7 @@ namespace osu.Game.Skinning.Editor
             foreach (var item in base.GetContextMenuItemsForSelection(selection))
                 yield return item;
 
-            IEnumerable<AnchorMenuItem> createAnchorItems(Func<Drawable, Anchor> checkFunction, Action<Anchor> applyFunction)
+            IEnumerable<TernaryStateMenuItem> createAnchorItems(Func<Drawable, Anchor> checkFunction, Action<Anchor> applyFunction)
             {
                 var displayableAnchors = new[]
                 {
@@ -117,7 +117,7 @@ namespace osu.Game.Skinning.Editor
 
                 return displayableAnchors.Select(a =>
                 {
-                    return new AnchorMenuItem(a, selection, _ => applyFunction(a))
+                    return new TernaryStateRadioMenuItem(a.ToString(), MenuItemType.Standard, _ => applyFunction(a))
                     {
                         State = { Value = GetStateFromSelection(selection, c => checkFunction((Drawable)c.Item) == a) }
                     };
@@ -166,15 +166,5 @@ namespace osu.Game.Skinning.Editor
                 scale.Y = scale.X;
             }
         }
-
-        public class AnchorMenuItem : TernaryStateMenuItem
-        {
-            public AnchorMenuItem(Anchor anchor, IEnumerable<SelectionBlueprint<ISkinnableDrawable>> selection, Action<TernaryState> action)
-                : base(anchor.ToString(), getNextState, MenuItemType.Standard, action)
-            {
-            }
-
-            private static TernaryState getNextState(TernaryState state) => TernaryState.True;
-        }
     }
 }

osu.Game/Skinning/HUDSkinComponents.cs

@@ -10,5 +10,7 @@ namespace osu.Game.Skinning
         AccuracyCounter,
         HealthDisplay,
         SongProgress,
+        BarHitErrorMeter,
+        ColourHitErrorMeter,
     }
 }

osu.Game/Skinning/LegacySkin.cs

@@ -19,6 +19,7 @@ using osu.Game.IO;
 using osu.Game.Rulesets.Scoring;
 using osu.Game.Screens.Play;
 using osu.Game.Screens.Play.HUD;
+using osu.Game.Screens.Play.HUD.HitErrorMeters;
 using osuTK.Graphics;
 
 namespace osu.Game.Skinning
@@ -342,6 +343,20 @@ namespace osu.Game.Skinning
                                 {
                                     accuracy.Y = container.ToLocalSpace(score.ScreenSpaceDrawQuad.BottomRight).Y;
                                 }
+
+                                var songProgress = container.OfType<SongProgress>().FirstOrDefault();
+
+                                var hitError = container.OfType<HitErrorMeter>().FirstOrDefault();
+
+                                if (hitError != null)
+                                {
+                                    hitError.Anchor = Anchor.BottomCentre;
+                                    hitError.Origin = Anchor.CentreLeft;
+                                    hitError.Rotation = -90;
+
+                                    if (songProgress != null)
+                                        hitError.Y -= SongProgress.MAX_HEIGHT;
+                                }
                             })
                             {
                                 Children = new[]
@@ -352,6 +367,7 @@ namespace osu.Game.Skinning
                                     GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.AccuracyCounter)) ?? new DefaultAccuracyCounter(),
                                     GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.HealthDisplay)) ?? new DefaultHealthDisplay(),
                                     GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.SongProgress)) ?? new SongProgress(),
+                                    GetDrawableComponent(new HUDSkinComponent(HUDSkinComponents.BarHitErrorMeter)) ?? new BarHitErrorMeter(),
                                 }
                             };
 

osu.Game/Tests/Visual/Multiplayer/MultiplayerTestScene.cs

@@ -19,7 +19,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         public const int PLAYER_1_ID = 55;
         public const int PLAYER_2_ID = 56;
 
-        [Cached(typeof(StatefulMultiplayerClient))]
+        [Cached(typeof(MultiplayerClient))]
         public TestMultiplayerClient Client { get; }
 
         [Cached(typeof(IRoomManager))]

osu.Game/Tests/Visual/Multiplayer/TestMultiplayerClient.cs

@@ -20,7 +20,7 @@ using osu.Game.Users;
 
 namespace osu.Game.Tests.Visual.Multiplayer
 {
-    public class TestMultiplayerClient : StatefulMultiplayerClient
+    public class TestMultiplayerClient : MultiplayerClient
     {
         public override IBindable<bool> IsConnected => isConnected;
         private readonly Bindable<bool> isConnected = new Bindable<bool>(true);

osu.Game/Tests/Visual/Multiplayer/TestMultiplayerRoomContainer.cs

@@ -16,7 +16,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         protected override Container<Drawable> Content => content;
         private readonly Container content;
 
-        [Cached(typeof(StatefulMultiplayerClient))]
+        [Cached(typeof(MultiplayerClient))]
         public readonly TestMultiplayerClient Client;
 
         [Cached(typeof(IRoomManager))]

osu.Game/Tests/Visual/PlacementBlueprintTestScene.cs

@@ -33,8 +33,12 @@ namespace osu.Game.Tests.Visual
         protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent)
         {
             var dependencies = new DependencyContainer(base.CreateChildDependencies(parent));
+
             dependencies.CacheAs(new EditorClock());
 
+            var playable = Beatmap.Value.GetPlayableBeatmap(Beatmap.Value.BeatmapInfo.Ruleset);
+            dependencies.CacheAs(new EditorBeatmap(playable));
+
             return dependencies;
         }
 

osu.Game/Tests/Visual/Spectator/TestSpectatorClient.cs

@@ -0,0 +1,110 @@
+// 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.
+
+#nullable enable
+
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Utils;
+using osu.Game.Online.API;
+using osu.Game.Online.Spectator;
+using osu.Game.Replays.Legacy;
+using osu.Game.Scoring;
+
+namespace osu.Game.Tests.Visual.Spectator
+{
+    public class TestSpectatorClient : SpectatorClient
+    {
+        public override IBindable<bool> IsConnected { get; } = new Bindable<bool>(true);
+
+        private readonly Dictionary<int, int> userBeatmapDictionary = new Dictionary<int, int>();
+
+        [Resolved]
+        private IAPIProvider api { get; set; } = null!;
+
+        /// <summary>
+        /// Starts play for an arbitrary user.
+        /// </summary>
+        /// <param name="userId">The user to start play for.</param>
+        /// <param name="beatmapId">The playing beatmap id.</param>
+        public void StartPlay(int userId, int beatmapId)
+        {
+            userBeatmapDictionary[userId] = beatmapId;
+            sendPlayingState(userId);
+        }
+
+        /// <summary>
+        /// Ends play for an arbitrary user.
+        /// </summary>
+        /// <param name="userId">The user to end play for.</param>
+        public void EndPlay(int userId)
+        {
+            if (!PlayingUsers.Contains(userId))
+                return;
+
+            ((ISpectatorClient)this).UserFinishedPlaying(userId, new SpectatorState
+            {
+                BeatmapID = userBeatmapDictionary[userId],
+                RulesetID = 0,
+            });
+        }
+
+        /// <summary>
+        /// Sends frames for an arbitrary user.
+        /// </summary>
+        /// <param name="userId">The user to send frames for.</param>
+        /// <param name="index">The frame index.</param>
+        /// <param name="count">The number of frames to send.</param>
+        public void SendFrames(int userId, int index, int count)
+        {
+            var frames = new List<LegacyReplayFrame>();
+
+            for (int i = index; i < index + count; i++)
+            {
+                var buttonState = i == index + count - 1 ? ReplayButtonState.None : ReplayButtonState.Left1;
+
+                frames.Add(new LegacyReplayFrame(i * 100, RNG.Next(0, 512), RNG.Next(0, 512), buttonState));
+            }
+
+            var bundle = new FrameDataBundle(new ScoreInfo { Combo = index + count }, frames);
+            ((ISpectatorClient)this).UserSentFrames(userId, bundle);
+        }
+
+        protected override Task BeginPlayingInternal(SpectatorState state)
+        {
+            // Track the local user's playing beatmap ID.
+            Debug.Assert(state.BeatmapID != null);
+            userBeatmapDictionary[api.LocalUser.Value.Id] = state.BeatmapID.Value;
+
+            return ((ISpectatorClient)this).UserBeganPlaying(api.LocalUser.Value.Id, state);
+        }
+
+        protected override Task SendFramesInternal(FrameDataBundle data) => ((ISpectatorClient)this).UserSentFrames(api.LocalUser.Value.Id, data);
+
+        protected override Task EndPlayingInternal(SpectatorState state) => ((ISpectatorClient)this).UserFinishedPlaying(api.LocalUser.Value.Id, state);
+
+        protected override Task WatchUserInternal(int userId)
+        {
+            // When newly watching a user, the server sends the playing state immediately.
+            if (PlayingUsers.Contains(userId))
+                sendPlayingState(userId);
+
+            return Task.CompletedTask;
+        }
+
+        protected override Task StopWatchingUserInternal(int userId) => Task.CompletedTask;
+
+        private void sendPlayingState(int userId)
+        {
+            ((ISpectatorClient)this).UserBeganPlaying(userId, new SpectatorState
+            {
+                BeatmapID = userBeatmapDictionary[userId],
+                RulesetID = 0,
+            });
+        }
+    }
+}

osu.Game/Tests/Visual/Spectator/TestSpectatorStreamingClient.cs

@@ -1,90 +0,0 @@
-// 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.Collections.Concurrent;
-using System.Collections.Generic;
-using osu.Framework.Bindables;
-using osu.Framework.Utils;
-using osu.Game.Online;
-using osu.Game.Online.Spectator;
-using osu.Game.Replays.Legacy;
-using osu.Game.Scoring;
-
-namespace osu.Game.Tests.Visual.Spectator
-{
-    public class TestSpectatorStreamingClient : SpectatorStreamingClient
-    {
-        public new BindableList<int> PlayingUsers => (BindableList<int>)base.PlayingUsers;
-        private readonly ConcurrentDictionary<int, byte> watchingUsers = new ConcurrentDictionary<int, byte>();
-
-        private readonly Dictionary<int, int> userBeatmapDictionary = new Dictionary<int, int>();
-        private readonly Dictionary<int, bool> userSentStateDictionary = new Dictionary<int, bool>();
-
-        public TestSpectatorStreamingClient()
-            : base(new DevelopmentEndpointConfiguration())
-        {
-        }
-
-        public void StartPlay(int userId, int beatmapId)
-        {
-            userBeatmapDictionary[userId] = beatmapId;
-            sendState(userId, beatmapId);
-        }
-
-        public void EndPlay(int userId, int beatmapId)
-        {
-            ((ISpectatorClient)this).UserFinishedPlaying(userId, new SpectatorState
-            {
-                BeatmapID = beatmapId,
-                RulesetID = 0,
-            });
-
-            userBeatmapDictionary.Remove(userId);
-            userSentStateDictionary.Remove(userId);
-        }
-
-        public void SendFrames(int userId, int index, int count)
-        {
-            var frames = new List<LegacyReplayFrame>();
-
-            for (int i = index; i < index + count; i++)
-            {
-                var buttonState = i == index + count - 1 ? ReplayButtonState.None : ReplayButtonState.Left1;
-
-                frames.Add(new LegacyReplayFrame(i * 100, RNG.Next(0, 512), RNG.Next(0, 512), buttonState));
-            }
-
-            var bundle = new FrameDataBundle(new ScoreInfo { Combo = index + count }, frames);
-            ((ISpectatorClient)this).UserSentFrames(userId, bundle);
-
-            if (!userSentStateDictionary[userId])
-                sendState(userId, userBeatmapDictionary[userId]);
-        }
-
-        public override void WatchUser(int userId)
-        {
-            base.WatchUser(userId);
-
-            // When newly watching a user, the server sends the playing state immediately.
-            if (watchingUsers.TryAdd(userId, 0) && PlayingUsers.Contains(userId))
-                sendState(userId, userBeatmapDictionary[userId]);
-        }
-
-        public override void StopWatchingUser(int userId)
-        {
-            base.StopWatchingUser(userId);
-            watchingUsers.TryRemove(userId, out _);
-        }
-
-        private void sendState(int userId, int beatmapId)
-        {
-            ((ISpectatorClient)this).UserBeganPlaying(userId, new SpectatorState
-            {
-                BeatmapID = beatmapId,
-                RulesetID = 0,
-            });
-
-            userSentStateDictionary[userId] = true;
-        }
-    }
-}