Merge branch 'update-framework' into settings-filter-fixes

.config/dotnet-tools.json

@@ -27,10 +27,10 @@
       ]
     },
     "ppy.localisationanalyser.tools": {
-      "version": "2022.320.0",
+      "version": "2022.417.0",
       "commands": [
         "localisation"
       ]
     }
   }
-}
+}

.github/workflows/ci.yml

@@ -2,6 +2,60 @@ on: [push, pull_request]
 name: Continuous Integration
 
 jobs:
+  inspect-code:
+    name: Code Quality
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      # FIXME: Tools won't run in .NET 6.0 unless you install 3.1.x LTS side by side.
+      # https://itnext.io/how-to-support-multiple-net-sdks-in-github-actions-workflows-b988daa884e
+      - name: Install .NET 3.1.x LTS
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "3.1.x"
+
+      - name: Install .NET 6.0.x
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: "6.0.x"
+
+      - name: Restore Tools
+        run: dotnet tool restore
+
+      - name: Restore Packages
+        run: dotnet restore
+
+      - name: Restore inspectcode cache
+        uses: actions/cache@v3
+        with:
+          path: ${{ github.workspace }}/inspectcode
+          key: inspectcode-${{ hashFiles('.config/dotnet-tools.json') }}-${{ hashFiles('.github/workflows/ci.yml' ) }}
+
+      - name: CodeFileSanity
+        run: |
+          # TODO: Add ignore filters and GitHub Workflow Command Reporting in CFS. That way we don't have to do this workaround.
+          # FIXME: Suppress warnings from templates project
+          exit_code=0
+          while read -r line; do
+            if [[ ! -z "$line" ]]; then
+              echo "::error::$line"
+              exit_code=1
+            fi
+          done <<< $(dotnet codefilesanity)
+          exit $exit_code
+
+      # Temporarily disabled due to test failures, but it won't work anyway until the tool is upgraded.
+      # - name: .NET Format (Dry Run)
+      #   run: dotnet format --dry-run --check
+
+      - name: InspectCode
+        run: dotnet jb inspectcode $(pwd)/osu.Desktop.slnf --no-build --output="inspectcodereport.xml" --caches-home="inspectcode" --verbosity=WARN
+
+      - name: NVika
+        run: dotnet nvika parsereport "${{github.workspace}}/inspectcodereport.xml" --treatwarningsaserrors
+
   test:
     name: Test
     runs-on: ${{matrix.os.fullname}}
@@ -93,58 +147,4 @@ jobs:
       # cannot accept .sln(f) files as arguments.
       # Build just the main game for now.
       - name: Build
-        run: msbuild osu.iOS/osu.iOS.csproj /restore /p:Configuration=Debug
+        run: msbuild osu.iOS/osu.iOS.csproj /restore /p:Configuration=Debug
-
-  inspect-code:
-    name: Code Quality
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout
-        uses: actions/checkout@v2
-
-      # FIXME: Tools won't run in .NET 6.0 unless you install 3.1.x LTS side by side.
-      # https://itnext.io/how-to-support-multiple-net-sdks-in-github-actions-workflows-b988daa884e
-      - name: Install .NET 3.1.x LTS
-        uses: actions/setup-dotnet@v1
-        with:
-          dotnet-version: "3.1.x"
-
-      - name: Install .NET 6.0.x
-        uses: actions/setup-dotnet@v1
-        with:
-          dotnet-version: "6.0.x"
-
-      - name: Restore Tools
-        run: dotnet tool restore
-
-      - name: Restore Packages
-        run: dotnet restore
-
-      - name: Restore inspectcode cache
-        uses: actions/cache@v3
-        with:
-          path: ${{ github.workspace }}/inspectcode
-          key: inspectcode-${{ hashFiles('.config/dotnet-tools.json') }}-${{ hashFiles('.github/workflows/ci.yml' ) }}
-
-      - name: CodeFileSanity
-        run: |
-          # TODO: Add ignore filters and GitHub Workflow Command Reporting in CFS. That way we don't have to do this workaround.
-          # FIXME: Suppress warnings from templates project
-          exit_code=0
-          while read -r line; do
-            if [[ ! -z "$line" ]]; then
-              echo "::error::$line"
-              exit_code=1
-            fi
-          done <<< $(dotnet codefilesanity)
-          exit $exit_code
-
-      # Temporarily disabled due to test failures, but it won't work anyway until the tool is upgraded.
-      # - name: .NET Format (Dry Run)
-      #   run: dotnet format --dry-run --check
-
-      - name: InspectCode
-        run: dotnet jb inspectcode $(pwd)/osu.Desktop.slnf --no-build --output="inspectcodereport.xml" --caches-home="inspectcode" --verbosity=WARN
-
-      - name: NVika
-        run: dotnet nvika parsereport "${{github.workspace}}/inspectcodereport.xml" --treatwarningsaserrors

osu.Android.props

@@ -51,8 +51,8 @@
     <Reference Include="Java.Interop" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="ppy.osu.Game.Resources" Version="2022.407.0" />
+    <PackageReference Include="ppy.osu.Game.Resources" Version="2022.417.0" />
-    <PackageReference Include="ppy.osu.Framework.Android" Version="2022.408.0" />
+    <PackageReference Include="ppy.osu.Framework.Android" Version="2022.421.0" />
   </ItemGroup>
   <ItemGroup Label="Transitive Dependencies">
     <!-- Realm needs to be directly referenced in all Xamarin projects, as it will not pull in its transitive dependencies otherwise. -->

osu.Desktop/Security/ElevatedPrivilegesChecker.cs

@@ -19,7 +19,7 @@ namespace osu.Desktop.Security
     public class ElevatedPrivilegesChecker : Component
     {
         [Resolved]
-        private NotificationOverlay notifications { get; set; }
+        private INotificationOverlay notifications { get; set; }
 
         private bool elevated;
 

osu.Desktop/Updater/SquirrelUpdateManager.cs

@@ -25,7 +25,7 @@ namespace osu.Desktop.Updater
     public class SquirrelUpdateManager : osu.Game.Updater.UpdateManager
     {
         private UpdateManager updateManager;
-        private NotificationOverlay notificationOverlay;
+        private INotificationOverlay notificationOverlay;
 
         public Task PrepareUpdateAsync() => UpdateManager.RestartAppWhenExited();
 
@@ -39,9 +39,9 @@ namespace osu.Desktop.Updater
         private readonly SquirrelLogger squirrelLogger = new SquirrelLogger();
 
         [BackgroundDependencyLoader]
-        private void load(NotificationOverlay notification)
+        private void load(INotificationOverlay notifications)
         {
-            notificationOverlay = notification;
+            notificationOverlay = notifications;
 
             SquirrelLocator.CurrentMutable.Register(() => squirrelLogger, typeof(ILogger));
         }

osu.Desktop/osu.Desktop.csproj

@@ -24,7 +24,7 @@
     <ProjectReference Include="..\osu.Game.Rulesets.Taiko\osu.Game.Rulesets.Taiko.csproj" />
   </ItemGroup>
   <ItemGroup Label="Package References">
-    <PackageReference Include="Clowd.Squirrel" Version="2.8.28-pre" />
+    <PackageReference Include="Clowd.Squirrel" Version="2.9.23-gc8da1a" />
     <PackageReference Include="Mono.Posix.NETStandard" Version="1.0.0" />
     <PackageReference Include="System.IO.Packaging" Version="6.0.0" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="5.0.14" />

osu.Game.Rulesets.Osu.Tests/LegacyMainCirclePieceTest.cs

@@ -0,0 +1,108 @@
+// 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.Diagnostics;
+using System.Linq;
+using Moq;
+using NUnit.Framework;
+using osu.Framework.Graphics.OpenGL.Textures;
+using osu.Framework.Graphics.Sprites;
+using osu.Framework.Graphics.Textures;
+using osu.Framework.Testing;
+using osu.Game.Rulesets.Osu.Skinning.Legacy;
+using osu.Game.Skinning;
+using osu.Game.Tests.Visual;
+
+namespace osu.Game.Rulesets.Osu.Tests
+{
+    [HeadlessTest]
+    public class LegacyMainCirclePieceTest : OsuTestScene
+    {
+        private static readonly object?[][] texture_priority_cases =
+        {
+            // default priority lookup
+            new object?[]
+            {
+                // available textures
+                new[] { @"hitcircle", @"hitcircleoverlay" },
+                // priority lookup prefix
+                null,
+                // expected circle and overlay
+                @"hitcircle", @"hitcircleoverlay",
+            },
+            // custom priority lookup
+            new object?[]
+            {
+                new[] { @"hitcircle", @"hitcircleoverlay", @"sliderstartcircle", @"sliderstartcircleoverlay" },
+                @"sliderstartcircle",
+                @"sliderstartcircle", @"sliderstartcircleoverlay",
+            },
+            // when no sprites are available for the specified prefix, fall back to "hitcircle"/"hitcircleoverlay".
+            new object?[]
+            {
+                new[] { @"hitcircle", @"hitcircleoverlay" },
+                @"sliderstartcircle",
+                @"hitcircle", @"hitcircleoverlay",
+            },
+            // when a circle is available for the specified prefix but no overlay exists, no overlay is displayed.
+            new object?[]
+            {
+                new[] { @"hitcircle", @"hitcircleoverlay", @"sliderstartcircle" },
+                @"sliderstartcircle",
+                @"sliderstartcircle", null
+            },
+            // when no circle is available for the specified prefix but an overlay exists, the overlay is ignored.
+            new object?[]
+            {
+                new[] { @"hitcircle", @"hitcircleoverlay", @"sliderstartcircleoverlay" },
+                @"sliderstartcircle",
+                @"hitcircle", @"hitcircleoverlay",
+            }
+        };
+
+        [TestCaseSource(nameof(texture_priority_cases))]
+        public void TestTexturePriorities(string[] textureFilenames, string priorityLookup, string? expectedCircle, string? expectedOverlay)
+        {
+            TestLegacyMainCirclePiece piece = null!;
+
+            AddStep("load circle piece", () =>
+            {
+                var skin = new Mock<ISkinSource>();
+
+                // shouldn't be required as GetTexture(string) calls GetTexture(string, WrapMode, WrapMode) by default,
+                // but moq doesn't handle that well, therefore explicitly requiring to use `CallBase`:
+                // https://github.com/moq/moq4/issues/972
+                skin.Setup(s => s.GetTexture(It.IsAny<string>())).CallBase();
+
+                skin.Setup(s => s.GetTexture(It.IsIn(textureFilenames), It.IsAny<WrapMode>(), It.IsAny<WrapMode>()))
+                    .Returns((string componentName, WrapMode _, WrapMode __) => new Texture(1, 1) { AssetName = componentName });
+
+                Child = new DependencyProvidingContainer
+                {
+                    CachedDependencies = new (Type, object)[] { (typeof(ISkinSource), skin.Object) },
+                    Child = piece = new TestLegacyMainCirclePiece(priorityLookup),
+                };
+
+                var sprites = this.ChildrenOfType<Sprite>().Where(s => s.Texture.AssetName != null).DistinctBy(s => s.Texture.AssetName).ToArray();
+                Debug.Assert(sprites.Length <= 2);
+            });
+
+            AddAssert("check circle sprite", () => piece.CircleSprite?.Texture?.AssetName == expectedCircle);
+            AddAssert("check overlay sprite", () => piece.OverlaySprite?.Texture?.AssetName == expectedOverlay);
+        }
+
+        private class TestLegacyMainCirclePiece : LegacyMainCirclePiece
+        {
+            public new Sprite? CircleSprite => base.CircleSprite.ChildrenOfType<Sprite>().DistinctBy(s => s.Texture.AssetName).SingleOrDefault();
+            public new Sprite? OverlaySprite => base.OverlaySprite.ChildrenOfType<Sprite>().DistinctBy(s => s.Texture.AssetName).SingleOrDefault();
+
+            public TestLegacyMainCirclePiece(string? priorityLookupPrefix)
+                : base(priorityLookupPrefix, false)
+            {
+            }
+        }
+    }
+}

osu.Game.Rulesets.Osu/Beatmaps/OsuBeatmap.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using osu.Game.Beatmaps;
+using osu.Game.Resources.Localisation.Web;
 using osu.Game.Rulesets.Osu.Objects;
 
 namespace osu.Game.Rulesets.Osu.Beatmaps
@@ -20,13 +21,13 @@ namespace osu.Game.Rulesets.Osu.Beatmaps
             {
                 new BeatmapStatistic
                 {
-                    Name = @"Circle Count",
+                    Name = BeatmapsetsStrings.ShowStatsCountCircles,
                     Content = circles.ToString(),
                     CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Circles),
                 },
                 new BeatmapStatistic
                 {
-                    Name = @"Slider Count",
+                    Name = BeatmapsetsStrings.ShowStatsCountSliders,
                     Content = sliders.ToString(),
                     CreateIcon = () => new BeatmapStatisticIcon(BeatmapStatisticsIconType.Sliders),
                 },

osu.Game.Rulesets.Osu/Skinning/Legacy/LegacyMainCirclePiece.cs

@@ -3,10 +3,10 @@
 
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
+using osu.Framework.Extensions.ObjectExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Sprites;
-using osu.Framework.Graphics.Textures;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Rulesets.Objects.Drawables;
@@ -16,63 +16,61 @@ using osu.Game.Skinning;
 using osuTK;
 using osuTK.Graphics;
 
+#nullable enable
+
 namespace osu.Game.Rulesets.Osu.Skinning.Legacy
 {
     public class LegacyMainCirclePiece : CompositeDrawable
     {
         public override bool RemoveCompletedTransforms => false;
 
-        private readonly string priorityLookup;
+        /// <summary>
+        /// A prioritised prefix to perform texture lookups with.
+        /// </summary>
+        private readonly string? priorityLookupPrefix;
+
         private readonly bool hasNumber;
 
-        public LegacyMainCirclePiece(string priorityLookup = null, bool hasNumber = true)
+        protected Drawable CircleSprite = null!;
+        protected Drawable OverlaySprite = null!;
+
+        protected Container OverlayLayer { get; private set; } = null!;
+
+        private SkinnableSpriteText hitCircleText = null!;
+
+        private readonly Bindable<Color4> accentColour = new Bindable<Color4>();
+        private readonly IBindable<int> indexInCurrentCombo = new Bindable<int>();
+
+        [Resolved(canBeNull: true)]
+        private DrawableHitObject? drawableObject { get; set; }
+
+        [Resolved]
+        private ISkinSource skin { get; set; } = null!;
+
+        public LegacyMainCirclePiece(string? priorityLookupPrefix = null, bool hasNumber = true)
         {
-            this.priorityLookup = priorityLookup;
+            this.priorityLookupPrefix = priorityLookupPrefix;
             this.hasNumber = hasNumber;
 
             Size = new Vector2(OsuHitObject.OBJECT_RADIUS * 2);
         }
 
-        private Drawable hitCircleSprite;
-
-        protected Container OverlayLayer { get; private set; }
-
-        private Drawable hitCircleOverlay;
-        private SkinnableSpriteText hitCircleText;
-
-        private readonly Bindable<Color4> accentColour = new Bindable<Color4>();
-        private readonly IBindable<int> indexInCurrentCombo = new Bindable<int>();
-
-        [Resolved]
-        private DrawableHitObject drawableObject { get; set; }
-
-        [Resolved]
-        private ISkinSource skin { get; set; }
-
         [BackgroundDependencyLoader]
         private void load()
         {
-            var drawableOsuObject = (DrawableOsuHitObject)drawableObject;
+            var drawableOsuObject = (DrawableOsuHitObject?)drawableObject;
 
-            bool allowFallback = false;
+            // if a base texture for the specified prefix exists, continue using it for subsequent lookups.
-
+            // otherwise fall back to the default prefix "hitcircle".
-            // attempt lookup using priority specification
+            string circleName = (priorityLookupPrefix != null && skin.GetTexture(priorityLookupPrefix) != null) ? priorityLookupPrefix : @"hitcircle";
-            Texture baseTexture = getTextureWithFallback(string.Empty);
-
-            // if the base texture was not found without a fallback, switch on fallback mode and re-perform the lookup.
-            if (baseTexture == null)
-            {
-                allowFallback = true;
-                baseTexture = getTextureWithFallback(string.Empty);
-            }
 
             // at this point, any further texture fetches should be correctly using the priority source if the base texture was retrieved using it.
-            // the flow above handles the case where a sliderendcircle.png is retrieved from the skin, but sliderendcircleoverlay.png doesn't exist.
+            // the conditional above handles the case where a sliderendcircle.png is retrieved from the skin, but sliderendcircleoverlay.png doesn't exist.
-            // expected behaviour in this scenario is not showing the overlay, rather than using hitcircleoverlay.png (potentially from the default/fall-through skin).
+            // expected behaviour in this scenario is not showing the overlay, rather than using hitcircleoverlay.png.
 
             InternalChildren = new[]
             {
-                hitCircleSprite = new KiaiFlashingDrawable(() => new Sprite { Texture = baseTexture })
+                CircleSprite = new KiaiFlashingDrawable(() => new Sprite { Texture = skin.GetTexture(circleName) })
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
@@ -81,7 +79,7 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
-                    Child = hitCircleOverlay = new KiaiFlashingDrawable(() => getAnimationWithFallback(@"overlay", 1000 / 2d))
+                    Child = OverlaySprite = new KiaiFlashingDrawable(() => skin.GetAnimation(@$"{circleName}overlay", true, true, frameLength: 1000 / 2d))
                     {
                         Anchor = Anchor.Centre,
                         Origin = Anchor.Centre,
@@ -105,39 +103,12 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
             bool overlayAboveNumber = skin.GetConfig<OsuSkinConfiguration, bool>(OsuSkinConfiguration.HitCircleOverlayAboveNumber)?.Value ?? true;
 
             if (overlayAboveNumber)
-                OverlayLayer.ChangeChildDepth(hitCircleOverlay, float.MinValue);
+                OverlayLayer.ChangeChildDepth(OverlaySprite, float.MinValue);
 
-            accentColour.BindTo(drawableObject.AccentColour);
+            if (drawableOsuObject != null)
-            indexInCurrentCombo.BindTo(drawableOsuObject.IndexInCurrentComboBindable);
-
-            Texture getTextureWithFallback(string name)
             {
-                Texture tex = null;
+                accentColour.BindTo(drawableOsuObject.AccentColour);
-
+                indexInCurrentCombo.BindTo(drawableOsuObject.IndexInCurrentComboBindable);
-                if (!string.IsNullOrEmpty(priorityLookup))
-                {
-                    tex = skin.GetTexture($"{priorityLookup}{name}");
-
-                    if (!allowFallback)
-                        return tex;
-                }
-
-                return tex ?? skin.GetTexture($"hitcircle{name}");
-            }
-
-            Drawable getAnimationWithFallback(string name, double frameLength)
-            {
-                Drawable animation = null;
-
-                if (!string.IsNullOrEmpty(priorityLookup))
-                {
-                    animation = skin.GetAnimation($"{priorityLookup}{name}", true, true, frameLength: frameLength);
-
-                    if (!allowFallback)
-                        return animation;
-                }
-
-                return animation ?? skin.GetAnimation($"hitcircle{name}", true, true, frameLength: frameLength);
             }
         }
 
@@ -145,28 +116,31 @@ namespace osu.Game.Rulesets.Osu.Skinning.Legacy
         {
             base.LoadComplete();
 
-            accentColour.BindValueChanged(colour => hitCircleSprite.Colour = LegacyColourCompatibility.DisallowZeroAlpha(colour.NewValue), true);
+            accentColour.BindValueChanged(colour => CircleSprite.Colour = LegacyColourCompatibility.DisallowZeroAlpha(colour.NewValue), true);
             if (hasNumber)
                 indexInCurrentCombo.BindValueChanged(index => hitCircleText.Text = (index.NewValue + 1).ToString(), true);
 
-            drawableObject.ApplyCustomUpdateState += updateStateTransforms;
+            if (drawableObject != null)
-            updateStateTransforms(drawableObject, drawableObject.State.Value);
+            {
+                drawableObject.ApplyCustomUpdateState += updateStateTransforms;
+                updateStateTransforms(drawableObject, drawableObject.State.Value);
+            }
         }
 
         private void updateStateTransforms(DrawableHitObject drawableHitObject, ArmedState state)
         {
             const double legacy_fade_duration = 240;
 
-            using (BeginAbsoluteSequence(drawableObject.HitStateUpdateTime))
+            using (BeginAbsoluteSequence(drawableObject.AsNonNull().HitStateUpdateTime))
             {
                 switch (state)
                 {
                     case ArmedState.Hit:
-                        hitCircleSprite.FadeOut(legacy_fade_duration, Easing.Out);
+                        CircleSprite.FadeOut(legacy_fade_duration, Easing.Out);
-                        hitCircleSprite.ScaleTo(1.4f, legacy_fade_duration, Easing.Out);
+                        CircleSprite.ScaleTo(1.4f, legacy_fade_duration, Easing.Out);
 
-                        hitCircleOverlay.FadeOut(legacy_fade_duration, Easing.Out);
+                        OverlaySprite.FadeOut(legacy_fade_duration, Easing.Out);
-                        hitCircleOverlay.ScaleTo(1.4f, legacy_fade_duration, Easing.Out);
+                        OverlaySprite.ScaleTo(1.4f, legacy_fade_duration, Easing.Out);
 
                         if (hasNumber)
                         {

osu.Game.Tests/Gameplay/TestSceneMasterGameplayClockContainer.cs

@@ -26,6 +26,12 @@ namespace osu.Game.Tests.Gameplay
             Dependencies.Cache(localConfig = new OsuConfigManager(LocalStorage));
         }
 
+        [SetUpSteps]
+        public void SetUpSteps()
+        {
+            AddStep("reset audio offset", () => localConfig.SetValue(OsuSetting.AudioOffset, 0.0));
+        }
+
         [Test]
         public void TestStartThenElapsedTime()
         {
@@ -36,7 +42,7 @@ namespace osu.Game.Tests.Gameplay
                 var working = CreateWorkingBeatmap(new OsuRuleset().RulesetInfo);
                 working.LoadTrack();
 
-                Add(gameplayClockContainer = new MasterGameplayClockContainer(working, 0));
+                Child = gameplayClockContainer = new MasterGameplayClockContainer(working, 0);
             });
 
             AddStep("start clock", () => gameplayClockContainer.Start());
@@ -53,7 +59,7 @@ namespace osu.Game.Tests.Gameplay
                 var working = CreateWorkingBeatmap(new OsuRuleset().RulesetInfo);
                 working.LoadTrack();
 
-                Add(gameplayClockContainer = new MasterGameplayClockContainer(working, 0));
+                Child = gameplayClockContainer = new MasterGameplayClockContainer(working, 0);
             });
 
             AddStep("start clock", () => gameplayClockContainer.Start());
@@ -73,26 +79,29 @@ namespace osu.Game.Tests.Gameplay
         public void TestSeekPerformsInGameplayTime(
             [Values(1.0, 0.5, 2.0)] double clockRate,
             [Values(0.0, 200.0, -200.0)] double userOffset,
-            [Values(false, true)] bool whileStopped)
+            [Values(false, true)] bool whileStopped,
+            [Values(false, true)] bool setAudioOffsetBeforeConstruction)
         {
             ClockBackedTestWorkingBeatmap working = null;
             GameplayClockContainer gameplayClockContainer = null;
 
+            if (setAudioOffsetBeforeConstruction)
+                AddStep($"preset audio offset to {userOffset}", () => localConfig.SetValue(OsuSetting.AudioOffset, userOffset));
+
             AddStep("create container", () =>
             {
                 working = new ClockBackedTestWorkingBeatmap(new OsuRuleset().RulesetInfo, new FramedClock(new ManualClock()), Audio);
                 working.LoadTrack();
 
-                Add(gameplayClockContainer = new MasterGameplayClockContainer(working, 0));
+                Child = gameplayClockContainer = new MasterGameplayClockContainer(working, 0);
 
-                if (whileStopped)
+                gameplayClockContainer.Reset(startClock: !whileStopped);
-                    gameplayClockContainer.Stop();
-
-                gameplayClockContainer.Reset();
             });
 
             AddStep($"set clock rate to {clockRate}", () => working.Track.AddAdjustment(AdjustableProperty.Frequency, new BindableDouble(clockRate)));
-            AddStep($"set audio offset to {userOffset}", () => localConfig.SetValue(OsuSetting.AudioOffset, userOffset));
+
+            if (!setAudioOffsetBeforeConstruction)
+                AddStep($"set audio offset to {userOffset}", () => localConfig.SetValue(OsuSetting.AudioOffset, userOffset));
 
             AddStep("seek to 2500", () => gameplayClockContainer.Seek(2500));
             AddAssert("gameplay clock time = 2500", () => Precision.AlmostEquals(gameplayClockContainer.CurrentTime, 2500, 10f));

osu.Game.Tests/Gameplay/TestSceneStoryboardSamples.cs

@@ -88,7 +88,7 @@ namespace osu.Game.Tests.Gameplay
         [Test]
         public void TestSampleHasLifetimeEndWithInitialClockTime()
         {
-            GameplayClockContainer gameplayContainer = null;
+            MasterGameplayClockContainer gameplayContainer = null;
             DrawableStoryboardSample sample = null;
 
             AddStep("create container", () =>
@@ -96,8 +96,11 @@ namespace osu.Game.Tests.Gameplay
                 var working = CreateWorkingBeatmap(new OsuRuleset().RulesetInfo);
                 working.LoadTrack();
 
-                Add(gameplayContainer = new MasterGameplayClockContainer(working, 1000, true)
+                const double start_time = 1000;
+
+                Add(gameplayContainer = new MasterGameplayClockContainer(working, start_time)
                 {
+                    StartTime = start_time,
                     IsPaused = { Value = true },
                     Child = new FrameStabilityContainer
                     {

osu.Game.Tests/Visual/Background/TestSceneUserDimBackgrounds.cs

@@ -359,9 +359,9 @@ namespace osu.Game.Tests.Visual.Background
             protected override BackgroundScreen CreateBackground() =>
                 new FadeAccessibleBackground(Beatmap.Value);
 
-            public override void OnEntering(IScreen last)
+            public override void OnEntering(ScreenTransitionEvent e)
             {
-                base.OnEntering(last);
+                base.OnEntering(e);
 
                 ApplyToBackground(b => ReplacesBackground.BindTo(b.StoryboardReplacesBackground));
             }

osu.Game.Tests/Visual/Collections/TestSceneManageCollectionsDialog.cs

@@ -50,7 +50,7 @@ namespace osu.Game.Tests.Visual.Collections
             });
 
             Dependencies.Cache(manager);
-            Dependencies.Cache(dialogOverlay);
+            Dependencies.CacheAs<IDialogOverlay>(dialogOverlay);
         }
 
         [SetUp]

osu.Game.Tests/Visual/Editing/TestSceneComposeScreen.cs

@@ -1,44 +1,71 @@
 // 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.Linq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
+using osu.Framework.Extensions.ObjectExtensions;
+using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Framework.Testing;
 using osu.Game.Rulesets.Edit;
 using osu.Game.Rulesets.Osu;
 using osu.Game.Rulesets.Osu.Beatmaps;
 using osu.Game.Screens.Edit;
 using osu.Game.Screens.Edit.Compose;
+using osu.Game.Skinning;
 
 namespace osu.Game.Tests.Visual.Editing
 {
     [TestFixture]
     public class TestSceneComposeScreen : EditorClockTestScene
     {
-        [Cached(typeof(EditorBeatmap))]
+        private EditorBeatmap editorBeatmap;
-        [Cached(typeof(IBeatSnapProvider))]
-        private readonly EditorBeatmap editorBeatmap =
-            new EditorBeatmap(new OsuBeatmap
-            {
-                BeatmapInfo =
-                {
-                    Ruleset = new OsuRuleset().RulesetInfo
-                }
-            });
 
         [Cached]
         private EditorClipboard clipboard = new EditorClipboard();
 
-        protected override void LoadComplete()
+        [SetUpSteps]
+        public void SetUpSteps()
         {
-            base.LoadComplete();
+            AddStep("setup compose screen", () =>
-
-            Beatmap.Value = CreateWorkingBeatmap(editorBeatmap.PlayableBeatmap);
-
-            Child = new ComposeScreen
             {
-                State = { Value = Visibility.Visible },
+                var beatmap = new OsuBeatmap
-            };
+                {
+                    BeatmapInfo = { Ruleset = new OsuRuleset().RulesetInfo }
+                };
+
+                editorBeatmap = new EditorBeatmap(beatmap, new LegacyBeatmapSkin(beatmap.BeatmapInfo, null));
+
+                Beatmap.Value = CreateWorkingBeatmap(editorBeatmap.PlayableBeatmap);
+
+                Child = new DependencyProvidingContainer
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    CachedDependencies = new (Type, object)[]
+                    {
+                        (typeof(EditorBeatmap), editorBeatmap),
+                        (typeof(IBeatSnapProvider), editorBeatmap),
+                    },
+                    Child = new ComposeScreen { State = { Value = Visibility.Visible } },
+                };
+            });
+
+            AddUntilStep("wait for composer", () => this.ChildrenOfType<HitObjectComposer>().SingleOrDefault()?.IsLoaded == true);
+        }
+
+        /// <summary>
+        /// Ensures that the skin of the edited beatmap is properly wrapped in a <see cref="LegacySkinTransformer"/>.
+        /// </summary>
+        [Test]
+        public void TestLegacyBeatmapSkinHasTransformer()
+        {
+            AddAssert("legacy beatmap skin has transformer", () =>
+            {
+                var sources = this.ChildrenOfType<BeatmapSkinProvidingContainer>().First().AllSources;
+                return sources.OfType<LegacySkinTransformer>().Count(t => t.Skin == editorBeatmap.BeatmapSkin.AsNonNull().Skin) == 1;
+            });
         }
     }
 }

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

@@ -56,10 +56,11 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             private double lastFrequency = double.MaxValue;
 
-            protected override void Update()
+            protected override void UpdateAfterChildren()
             {
-                base.Update();
+                base.UpdateAfterChildren();
 
+                // This must be done in UpdateAfterChildren to allow the gameplay clock to have updated before checking values.
                 double freq = Beatmap.Value.Track.AggregateFrequency.Value;
 
                 FrequencyIncreased |= freq > lastFrequency;

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

@@ -1,12 +1,10 @@
 // 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.Diagnostics;
 using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Graphics;
 using osu.Framework.Timing;
-using osu.Framework.Utils;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Rulesets.Osu;
@@ -36,10 +34,10 @@ namespace osu.Game.Tests.Visual.Gameplay
                 BeatmapInfo = { AudioLeadIn = leadIn }
             });
 
-            AddAssert($"first frame is {expectedStartTime}", () =>
+            AddStep("check first frame time", () =>
             {
-                Debug.Assert(player.FirstFrameClockTime != null);
+                Assert.That(player.FirstFrameClockTime, Is.Not.Null);
-                return Precision.AlmostEquals(player.FirstFrameClockTime.Value, expectedStartTime, lenience_ms);
+                Assert.That(player.FirstFrameClockTime.Value, Is.EqualTo(expectedStartTime).Within(lenience_ms));
             });
         }
 
@@ -59,10 +57,10 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             loadPlayerWithBeatmap(new TestBeatmap(new OsuRuleset().RulesetInfo), storyboard);
 
-            AddAssert($"first frame is {expectedStartTime}", () =>
+            AddStep("check first frame time", () =>
             {
-                Debug.Assert(player.FirstFrameClockTime != null);
+                Assert.That(player.FirstFrameClockTime, Is.Not.Null);
-                return Precision.AlmostEquals(player.FirstFrameClockTime.Value, expectedStartTime, lenience_ms);
+                Assert.That(player.FirstFrameClockTime.Value, Is.EqualTo(expectedStartTime).Within(lenience_ms));
             });
         }
 
@@ -97,10 +95,10 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             loadPlayerWithBeatmap(new TestBeatmap(new OsuRuleset().RulesetInfo), storyboard);
 
-            AddAssert($"first frame is {expectedStartTime}", () =>
+            AddStep("check first frame time", () =>
             {
-                Debug.Assert(player.FirstFrameClockTime != null);
+                Assert.That(player.FirstFrameClockTime, Is.Not.Null);
-                return Precision.AlmostEquals(player.FirstFrameClockTime.Value, expectedStartTime, lenience_ms);
+                Assert.That(player.FirstFrameClockTime.Value, Is.EqualTo(expectedStartTime).Within(lenience_ms));
             });
         }
 

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

@@ -389,9 +389,9 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             public void ExitViaQuickExit() => PerformExit(false);
 
-            public override void OnEntering(IScreen last)
+            public override void OnEntering(ScreenTransitionEvent e)
             {
-                base.OnEntering(last);
+                base.OnEntering(e);
                 GameplayClockContainer.Stop();
             }
         }

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

@@ -43,7 +43,7 @@ namespace osu.Game.Tests.Visual.Gameplay
         [Resolved]
         private SessionStatics sessionStatics { get; set; }
 
-        [Cached]
+        [Cached(typeof(INotificationOverlay))]
         private readonly NotificationOverlay notificationOverlay;
 
         [Cached]

osu.Game.Tests/Visual/Menus/IntroTestScene.cs

@@ -26,7 +26,7 @@ namespace osu.Game.Tests.Visual.Menus
 
         private IntroScreen intro;
 
-        [Cached]
+        [Cached(typeof(INotificationOverlay))]
         private NotificationOverlay notifications;
 
         private ScheduledDelegate trackResetDelegate;

osu.Game.Tests/Visual/Menus/TestSceneToolbar.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Linq;
+using Moq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
@@ -22,6 +23,17 @@ namespace osu.Game.Tests.Visual.Menus
         [Resolved]
         private IRulesetStore rulesets { get; set; }
 
+        private readonly Mock<INotificationOverlay> notifications = new Mock<INotificationOverlay>();
+
+        private readonly BindableInt unreadNotificationCount = new BindableInt();
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Dependencies.CacheAs(notifications.Object);
+            notifications.SetupGet(n => n.UnreadCount).Returns(unreadNotificationCount);
+        }
+
         [SetUp]
         public void SetUp() => Schedule(() =>
         {
@@ -31,10 +43,6 @@ namespace osu.Game.Tests.Visual.Menus
         [Test]
         public void TestNotificationCounter()
         {
-            ToolbarNotificationButton notificationButton = null;
-
-            AddStep("retrieve notification button", () => notificationButton = toolbar.ChildrenOfType<ToolbarNotificationButton>().Single());
-
             setNotifications(1);
             setNotifications(2);
             setNotifications(3);
@@ -43,7 +51,7 @@ namespace osu.Game.Tests.Visual.Menus
 
             void setNotifications(int count)
                 => AddStep($"set notification count to {count}",
-                    () => notificationButton.NotificationCount.Value = count);
+                    () => unreadNotificationCount.Value = count);
         }
 
         [TestCase(false)]

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

@@ -0,0 +1,37 @@
+// 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.Graphics.Containers;
+using osu.Framework.Testing;
+using osu.Game.Overlays.Mods;
+using osu.Game.Screens.OnlinePlay;
+
+namespace osu.Game.Tests.Visual.Multiplayer
+{
+    public class TestSceneFreeModSelectScreen : MultiplayerTestScene
+    {
+        [Test]
+        public void TestFreeModSelect()
+        {
+            FreeModSelectScreen freeModSelectScreen = null;
+
+            AddStep("create free mod select screen", () => Child = freeModSelectScreen = new FreeModSelectScreen
+            {
+                State = { Value = Visibility.Visible }
+            });
+
+            AddAssert("all visible mods are playable",
+                () => this.ChildrenOfType<ModPanel>()
+                          .Where(panel => panel.IsPresent)
+                          .All(panel => panel.Mod.HasImplementation && panel.Mod.UserPlayable));
+
+            AddToggleStep("toggle visibility", visible =>
+            {
+                if (freeModSelectScreen != null)
+                    freeModSelectScreen.State.Value = visible ? Visibility.Visible : Visibility.Hidden;
+            });
+        }
+    }
+}

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

@@ -3,80 +3,155 @@
 
 using System;
 using System.Linq;
+using Moq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
-using osu.Framework.Audio;
 using osu.Framework.Bindables;
 using osu.Framework.Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Cursor;
 using osu.Framework.Graphics.UserInterface;
-using osu.Framework.Platform;
+using osu.Framework.Logging;
 using osu.Framework.Testing;
 using osu.Framework.Utils;
-using osu.Game.Beatmaps;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Online.Multiplayer;
 using osu.Game.Online.Multiplayer.Countdown;
 using osu.Game.Online.Rooms;
-using osu.Game.Rulesets;
+using osu.Game.Screens.OnlinePlay;
 using osu.Game.Screens.OnlinePlay.Multiplayer.Match;
-using osu.Game.Tests.Resources;
 using osuTK;
 using osuTK.Input;
 
 namespace osu.Game.Tests.Visual.Multiplayer
 {
-    public class TestSceneMatchStartControl : MultiplayerTestScene
+    public class TestSceneMatchStartControl : OsuManualInputManagerTestScene
     {
+        private readonly Mock<MultiplayerClient> multiplayerClient = new Mock<MultiplayerClient>();
+        private readonly Mock<OnlinePlayBeatmapAvailabilityTracker> availabilityTracker = new Mock<OnlinePlayBeatmapAvailabilityTracker>();
+
+        private readonly Bindable<BeatmapAvailability> beatmapAvailability = new Bindable<BeatmapAvailability>();
+        private readonly Bindable<Room> room = new Bindable<Room>();
+
+        private MultiplayerRoom multiplayerRoom;
+        private MultiplayerRoomUser localUser;
+        private OngoingOperationTracker ongoingOperationTracker;
+
+        private PopoverContainer content;
         private MatchStartControl control;
-        private BeatmapSetInfo importedSet;
 
-        private readonly Bindable<PlaylistItem> selectedItem = new Bindable<PlaylistItem>();
+        private OsuButton readyButton => control.ChildrenOfType<OsuButton>().Single();
 
-        private BeatmapManager beatmaps;
+        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent) =>
-        private RulesetStore rulesets;
+            new CachedModelDependencyContainer<Room>(base.CreateChildDependencies(parent)) { Model = { BindTarget = room } };
 
         [BackgroundDependencyLoader]
-        private void load(GameHost host, AudioManager audio)
+        private void load()
         {
-            Dependencies.Cache(rulesets = new RealmRulesetStore(Realm));
+            Dependencies.CacheAs(multiplayerClient.Object);
-            Dependencies.Cache(beatmaps = new BeatmapManager(LocalStorage, Realm, rulesets, null, audio, Resources, host, Beatmap.Default));
+            Dependencies.CacheAs(ongoingOperationTracker = new OngoingOperationTracker());
-            Dependencies.Cache(Realm);
+            Dependencies.CacheAs(availabilityTracker.Object);
+
+            availabilityTracker.SetupGet(a => a.Availability).Returns(beatmapAvailability);
+
+            multiplayerClient.SetupGet(m => m.LocalUser).Returns(() => localUser);
+            multiplayerClient.SetupGet(m => m.Room).Returns(() => multiplayerRoom);
+
+            // By default, the local user is to be the host.
+            multiplayerClient.SetupGet(m => m.IsHost).Returns(() => ReferenceEquals(multiplayerRoom.Host, localUser));
+
+            // Assume all state changes are accepted by the server.
+            multiplayerClient.Setup(m => m.ChangeState(It.IsAny<MultiplayerUserState>()))
+                             .Callback((MultiplayerUserState r) =>
+                             {
+                                 Logger.Log($"Changing local user state from {localUser.State} to {r}");
+                                 localUser.State = r;
+                                 raiseRoomUpdated();
+                             });
+
+            multiplayerClient.Setup(m => m.StartMatch())
+                             .Callback(() =>
+                             {
+                                 multiplayerClient.Raise(m => m.LoadRequested -= null);
+
+                                 // immediately "end" gameplay, as we don't care about that part of the process.
+                                 changeUserState(localUser.UserID, MultiplayerUserState.Idle);
+                             });
+
+            multiplayerClient.Setup(m => m.SendMatchRequest(It.IsAny<MatchUserRequest>()))
+                             .Callback((MatchUserRequest request) =>
+                             {
+                                 switch (request)
+                                 {
+                                     case StartMatchCountdownRequest countdownStart:
+                                         setRoomCountdown(countdownStart.Duration);
+                                         break;
+
+                                     case StopCountdownRequest _:
+                                         multiplayerRoom.Countdown = null;
+                                         raiseRoomUpdated();
+                                         break;
+                                 }
+                             });
+
+            Children = new Drawable[]
+            {
+                ongoingOperationTracker,
+                content = new PopoverContainer { RelativeSizeAxes = Axes.Both }
+            };
         }
 
-        [SetUp]
+        [SetUpSteps]
-        public new void Setup() => Schedule(() =>
+        public void SetUpSteps()
         {
-            AvailabilityTracker.SelectedItem.BindTo(selectedItem);
+            AddStep("reset state", () =>
-
-            beatmaps.Import(TestResources.GetQuickTestBeatmapForImport()).WaitSafely();
-            importedSet = beatmaps.GetAllUsableBeatmapSets().First();
-            Beatmap.Value = beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First());
-
-            selectedItem.Value = new PlaylistItem(Beatmap.Value.BeatmapInfo)
             {
-                RulesetID = Beatmap.Value.BeatmapInfo.Ruleset.OnlineID
+                multiplayerClient.Invocations.Clear();
-            };
 
-            Child = new PopoverContainer
+                beatmapAvailability.Value = BeatmapAvailability.LocallyAvailable();
+
+                var playlistItem = new PlaylistItem(Beatmap.Value.BeatmapInfo)
+                {
+                    RulesetID = Beatmap.Value.BeatmapInfo.Ruleset.OnlineID
+                };
+
+                room.Value = new Room
+                {
+                    Playlist = { playlistItem },
+                    CurrentPlaylistItem = { Value = playlistItem }
+                };
+
+                localUser = new MultiplayerRoomUser(API.LocalUser.Value.Id) { User = API.LocalUser.Value };
+
+                multiplayerRoom = new MultiplayerRoom(0)
+                {
+                    Playlist =
+                    {
+                        new MultiplayerPlaylistItem(playlistItem),
+                    },
+                    Users = { localUser },
+                    Host = localUser,
+                };
+            });
+
+            AddStep("create control", () =>
             {
-                RelativeSizeAxes = Axes.Both,
+                content.Child = control = new MatchStartControl
-                Child = control = new MatchStartControl
                 {
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
                     Size = new Vector2(250, 50),
-                }
+                };
-            };
+            });
-        });
+        }
 
         [Test]
         public void TestStartWithCountdown()
         {
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
             AddUntilStep("countdown button shown", () => this.ChildrenOfType<MultiplayerCountdownButton>().SingleOrDefault()?.IsPresent == true);
+
             ClickButtonWhenEnabled<MultiplayerCountdownButton>();
             AddStep("click the first countdown button", () =>
             {
@@ -85,8 +160,12 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 InputManager.Click(MouseButton.Left);
             });
 
-            AddStep("finish countdown", () => MultiplayerClient.SkipToEndOfCountdown());
+            AddStep("check request received", () =>
-            AddUntilStep("match started", () => MultiplayerClient.LocalUser?.State == MultiplayerUserState.WaitingForLoad);
+            {
+                multiplayerClient.Verify(m => m.SendMatchRequest(It.Is<StartMatchCountdownRequest>(req =>
+                    req.Duration == TimeSpan.FromSeconds(10)
+                )), Times.Once);
+            });
         }
 
         [Test]
@@ -94,6 +173,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
             AddUntilStep("countdown button shown", () => this.ChildrenOfType<MultiplayerCountdownButton>().SingleOrDefault()?.IsPresent == true);
+
             ClickButtonWhenEnabled<MultiplayerCountdownButton>();
             AddStep("click the first countdown button", () =>
             {
@@ -102,6 +182,13 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 InputManager.Click(MouseButton.Left);
             });
 
+            AddStep("check request received", () =>
+            {
+                multiplayerClient.Verify(m => m.SendMatchRequest(It.Is<StartMatchCountdownRequest>(req =>
+                    req.Duration == TimeSpan.FromSeconds(10)
+                )), Times.Once);
+            });
+
             ClickButtonWhenEnabled<MultiplayerCountdownButton>();
             AddStep("click the cancel button", () =>
             {
@@ -110,41 +197,39 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 InputManager.Click(MouseButton.Left);
             });
 
-            AddStep("finish countdown", () => MultiplayerClient.SkipToEndOfCountdown());
+            AddStep("check request received", () =>
-            AddUntilStep("match not started", () => MultiplayerClient.LocalUser?.State == MultiplayerUserState.Ready);
+            {
+                multiplayerClient.Verify(m => m.SendMatchRequest(It.IsAny<StopCountdownRequest>()), Times.Once);
+            });
         }
 
         [Test]
         public void TestReadyAndUnReadyDuringCountdown()
         {
-            AddStep("add second user as host", () =>
+            AddStep("add second user as host", () => addUser(new APIUser { Id = 2, Username = "Another user" }, true));
-            {
-                MultiplayerClient.AddUser(new APIUser { Id = 2, Username = "Another user" });
-                MultiplayerClient.TransferHost(2);
-            });
 
-            AddStep("start with countdown", () => MultiplayerClient.SendMatchRequest(new StartMatchCountdownRequest { Duration = TimeSpan.FromMinutes(2) }).WaitSafely());
+            AddStep("start countdown", () => setRoomCountdown(TimeSpan.FromMinutes(1)));
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("user is ready", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("user is idle", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.Idle);
+            checkLocalUserState(MultiplayerUserState.Idle);
         }
 
         [Test]
         public void TestCountdownWhileSpectating()
         {
-            AddStep("set spectating", () => MultiplayerClient.ChangeUserState(API.LocalUser.Value.OnlineID, MultiplayerUserState.Spectating));
+            AddStep("set spectating", () => changeUserState(API.LocalUser.Value.OnlineID, MultiplayerUserState.Spectating));
-            AddUntilStep("local user is spectating", () => MultiplayerClient.LocalUser?.State == MultiplayerUserState.Spectating);
+            checkLocalUserState(MultiplayerUserState.Spectating);
 
             AddAssert("countdown button is visible", () => this.ChildrenOfType<MultiplayerCountdownButton>().Single().IsPresent);
             AddAssert("countdown button enabled", () => this.ChildrenOfType<MultiplayerCountdownButton>().Single().Enabled.Value);
 
-            AddStep("add second user", () => MultiplayerClient.AddUser(new APIUser { Id = 2, Username = "Another user" }));
+            AddStep("add second user", () => addUser(new APIUser { Id = 2, Username = "Another user" }));
             AddAssert("countdown button enabled", () => this.ChildrenOfType<MultiplayerCountdownButton>().Single().Enabled.Value);
 
-            AddStep("set second user ready", () => MultiplayerClient.ChangeUserState(2, MultiplayerUserState.Ready));
+            AddStep("set second user ready", () => changeUserState(2, MultiplayerUserState.Ready));
             AddAssert("countdown button enabled", () => this.ChildrenOfType<MultiplayerCountdownButton>().Single().Enabled.Value);
         }
 
@@ -153,60 +238,54 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             AddStep("add second user as host", () =>
             {
-                MultiplayerClient.AddUser(new APIUser { Id = 2, Username = "Another user" });
+                addUser(new APIUser { Id = 2, Username = "Another user" }, true);
-                MultiplayerClient.TransferHost(2);
             });
 
-            AddStep("start countdown", () => MultiplayerClient.SendMatchRequest(new StartMatchCountdownRequest { Duration = TimeSpan.FromMinutes(1) }).WaitSafely());
+            AddStep("start countdown", () => multiplayerClient.Object.SendMatchRequest(new StartMatchCountdownRequest { Duration = TimeSpan.FromMinutes(1) }).WaitSafely());
-            AddUntilStep("countdown started", () => MultiplayerClient.Room?.Countdown != null);
+            AddUntilStep("countdown started", () => multiplayerRoom.Countdown != null);
 
-            AddStep("transfer host to local user", () => MultiplayerClient.TransferHost(API.LocalUser.Value.OnlineID));
+            AddStep("transfer host to local user", () => transferHost(localUser));
-            AddUntilStep("local user is host", () => MultiplayerClient.Room?.Host?.Equals(MultiplayerClient.LocalUser) == true);
+            AddUntilStep("local user is host", () => multiplayerRoom.Host?.Equals(multiplayerClient.Object.LocalUser) == true);
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("local user became ready", () => MultiplayerClient.LocalUser?.State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
-            AddAssert("countdown still active", () => MultiplayerClient.Room?.Countdown != null);
+            AddAssert("countdown still active", () => multiplayerRoom.Countdown != null);
         }
 
         [Test]
-        public void TestCountdownButtonVisibilityWithAutoStartEnablement()
+        public void TestCountdownButtonVisibilityWithAutoStart()
         {
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("local user became ready", () => MultiplayerClient.LocalUser?.State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
             AddUntilStep("countdown button visible", () => this.ChildrenOfType<MultiplayerCountdownButton>().Single().IsPresent);
 
-            AddStep("enable auto start", () => MultiplayerClient.ChangeSettings(new MultiplayerRoomSettings { AutoStartDuration = TimeSpan.FromMinutes(1) }).WaitSafely());
+            AddStep("enable auto start", () => changeRoomSettings(new MultiplayerRoomSettings { AutoStartDuration = TimeSpan.FromMinutes(1) }));
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("local user became ready", () => MultiplayerClient.LocalUser?.State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
             AddUntilStep("countdown button not visible", () => !this.ChildrenOfType<MultiplayerCountdownButton>().Single().IsPresent);
         }
 
         [Test]
         public void TestClickingReadyButtonUnReadiesDuringAutoStart()
         {
-            AddStep("enable auto start", () => MultiplayerClient.ChangeSettings(new MultiplayerRoomSettings { AutoStartDuration = TimeSpan.FromMinutes(1) }).WaitSafely());
+            AddStep("enable auto start", () => changeRoomSettings(new MultiplayerRoomSettings { AutoStartDuration = TimeSpan.FromMinutes(1) }));
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("local user became ready", () => MultiplayerClient.LocalUser?.State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("local user became idle", () => MultiplayerClient.LocalUser?.State == MultiplayerUserState.Idle);
+            checkLocalUserState(MultiplayerUserState.Idle);
         }
 
         [Test]
         public void TestDeletedBeatmapDisableReady()
         {
-            OsuButton readyButton = null;
+            AddUntilStep("ready button enabled", () => readyButton.Enabled.Value);
 
-            AddUntilStep("ensure ready button enabled", () =>
+            AddStep("mark beatmap not available", () => beatmapAvailability.Value = BeatmapAvailability.NotDownloaded());
-            {
-                readyButton = control.ChildrenOfType<OsuButton>().Single();
-                return readyButton.Enabled.Value;
-            });
-
-            AddStep("delete beatmap", () => beatmaps.Delete(importedSet));
             AddUntilStep("ready button disabled", () => !readyButton.Enabled.Value);
-            AddStep("undelete beatmap", () => beatmaps.Undelete(importedSet));
+
+            AddStep("mark beatmap available", () => beatmapAvailability.Value = BeatmapAvailability.LocallyAvailable());
             AddUntilStep("ready button enabled back", () => readyButton.Enabled.Value);
         }
 
@@ -215,31 +294,25 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             AddStep("add second user as host", () =>
             {
-                MultiplayerClient.AddUser(new APIUser { Id = 2, Username = "Another user" });
+                addUser(new APIUser { Id = 2, Username = "Another user" }, true);
-                MultiplayerClient.TransferHost(2);
             });
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("user is ready", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("user is idle", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.Idle);
+            checkLocalUserState(MultiplayerUserState.Idle);
         }
 
         [TestCase(true)]
         [TestCase(false)]
         public void TestToggleStateWhenHost(bool allReady)
         {
-            AddStep("setup", () =>
+            if (!allReady)
-            {
+                AddStep("add other user", () => addUser(new APIUser { Id = 2, Username = "Another user" }));
-                MultiplayerClient.TransferHost(MultiplayerClient.Room?.Users[0].UserID ?? 0);
-
-                if (!allReady)
-                    MultiplayerClient.AddUser(new APIUser { Id = 2, Username = "Another user" });
-            });
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("user is ready", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
 
             verifyGameplayStartFlow();
         }
@@ -249,12 +322,12 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             AddStep("add host", () =>
             {
-                MultiplayerClient.AddUser(new APIUser { Id = 2, Username = "Another user" });
+                addUser(new APIUser { Id = 2, Username = "Another user" }, true);
-                MultiplayerClient.TransferHost(2);
             });
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddStep("make user host", () => MultiplayerClient.TransferHost(MultiplayerClient.Room?.Users[0].UserID ?? 0));
+
+            AddStep("make local user host", () => transferHost(localUser));
 
             verifyGameplayStartFlow();
         }
@@ -264,18 +337,17 @@ namespace osu.Game.Tests.Visual.Multiplayer
         {
             AddStep("setup", () =>
             {
-                MultiplayerClient.TransferHost(MultiplayerClient.Room?.Users[0].UserID ?? 0);
+                addUser(new APIUser { Id = 2, Username = "Another user" });
-                MultiplayerClient.AddUser(new APIUser { Id = 2, Username = "Another user" });
             });
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("user is ready", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
 
-            AddStep("transfer host", () => MultiplayerClient.TransferHost(MultiplayerClient.Room?.Users[1].UserID ?? 0));
+            AddStep("transfer host", () => transferHost(multiplayerRoom.Users[1]));
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("user is idle (match not started)", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.Idle);
+            checkLocalUserState(MultiplayerUserState.Idle);
-            AddUntilStep("ready button enabled", () => control.ChildrenOfType<OsuButton>().Single().Enabled.Value);
+            AddUntilStep("ready button enabled", () => readyButton.Enabled.Value);
         }
 
         [TestCase(true)]
@@ -283,44 +355,83 @@ namespace osu.Game.Tests.Visual.Multiplayer
         public void TestManyUsersChangingState(bool isHost)
         {
             const int users = 10;
-            AddStep("setup", () =>
-            {
-                MultiplayerClient.TransferHost(MultiplayerClient.Room?.Users[0].UserID ?? 0);
-                for (int i = 0; i < users; i++)
-                    MultiplayerClient.AddUser(new APIUser { Id = i, Username = "Another user" });
-            });
 
-            if (!isHost)
+            AddStep("add many users", () =>
-                AddStep("transfer host", () => MultiplayerClient.TransferHost(2));
+            {
+                for (int i = 0; i < users; i++)
+                    addUser(new APIUser { Id = i, Username = "Another user" }, !isHost && i == 2);
+            });
 
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
 
             AddRepeatStep("change user ready state", () =>
             {
-                MultiplayerClient.ChangeUserState(RNG.Next(0, users), RNG.NextBool() ? MultiplayerUserState.Ready : MultiplayerUserState.Idle);
+                changeUserState(RNG.Next(0, users), RNG.NextBool() ? MultiplayerUserState.Ready : MultiplayerUserState.Idle);
             }, 20);
 
             AddRepeatStep("ready all users", () =>
             {
-                var nextUnready = MultiplayerClient.Room?.Users.FirstOrDefault(c => c.State == MultiplayerUserState.Idle);
+                var nextUnready = multiplayerRoom.Users.FirstOrDefault(c => c.State == MultiplayerUserState.Idle);
                 if (nextUnready != null)
-                    MultiplayerClient.ChangeUserState(nextUnready.UserID, MultiplayerUserState.Ready);
+                    changeUserState(nextUnready.UserID, MultiplayerUserState.Ready);
             }, users);
         }
 
         private void verifyGameplayStartFlow()
         {
-            AddUntilStep("user is ready", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.Ready);
+            checkLocalUserState(MultiplayerUserState.Ready);
             ClickButtonWhenEnabled<MultiplayerReadyButton>();
-            AddUntilStep("user waiting for load", () => MultiplayerClient.Room?.Users[0].State == MultiplayerUserState.WaitingForLoad);
 
-            AddStep("finish gameplay", () =>
+            AddStep("check start request received", () => multiplayerClient.Verify(m => m.StartMatch(), Times.Once));
-            {
-                MultiplayerClient.ChangeUserState(MultiplayerClient.Room?.Users[0].UserID ?? 0, MultiplayerUserState.Loaded);
-                MultiplayerClient.ChangeUserState(MultiplayerClient.Room?.Users[0].UserID ?? 0, MultiplayerUserState.FinishedPlay);
-            });
-
-            AddUntilStep("ready button enabled", () => control.ChildrenOfType<OsuButton>().Single().Enabled.Value);
         }
+
+        private void checkLocalUserState(MultiplayerUserState state) =>
+            AddUntilStep($"local user is {state}", () => localUser.State == state);
+
+        private void setRoomCountdown(TimeSpan duration)
+        {
+            multiplayerRoom.Countdown = new MatchStartCountdown { TimeRemaining = duration };
+            raiseRoomUpdated();
+        }
+
+        private void changeUserState(int userId, MultiplayerUserState newState)
+        {
+            multiplayerRoom.Users.Single(u => u.UserID == userId).State = newState;
+            raiseRoomUpdated();
+        }
+
+        private void addUser(APIUser user, bool asHost = false)
+        {
+            var multiplayerRoomUser = new MultiplayerRoomUser(user.Id) { User = user };
+
+            multiplayerRoom.Users.Add(multiplayerRoomUser);
+
+            if (asHost)
+                transferHost(multiplayerRoomUser);
+
+            raiseRoomUpdated();
+        }
+
+        private void transferHost(MultiplayerRoomUser user)
+        {
+            multiplayerRoom.Host = user;
+            raiseRoomUpdated();
+        }
+
+        private void changeRoomSettings(MultiplayerRoomSettings settings)
+        {
+            multiplayerRoom.Settings = settings;
+
+            // Changing settings should reset all user ready statuses.
+            foreach (var user in multiplayerRoom.Users)
+            {
+                if (user.State == MultiplayerUserState.Ready)
+                    user.State = MultiplayerUserState.Idle;
+            }
+
+            raiseRoomUpdated();
+        }
+
+        private void raiseRoomUpdated() => multiplayerClient.Raise(m => m.RoomUpdated -= null);
     }
 }

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

@@ -464,16 +464,16 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
         private class TestMultiSpectatorScreen : MultiSpectatorScreen
         {
-            private readonly double? gameplayStartTime;
+            private readonly double? startTime;
 
-            public TestMultiSpectatorScreen(Room room, MultiplayerRoomUser[] users, double? gameplayStartTime = null)
+            public TestMultiSpectatorScreen(Room room, MultiplayerRoomUser[] users, double? startTime = null)
                 : base(room, users)
             {
-                this.gameplayStartTime = gameplayStartTime;
+                this.startTime = startTime;
             }
 
             protected override MasterGameplayClockContainer CreateMasterGameplayClockContainer(WorkingBeatmap beatmap)
-                => new MasterGameplayClockContainer(beatmap, gameplayStartTime ?? 0, gameplayStartTime.HasValue);
+                => new MasterGameplayClockContainer(beatmap, 0) { StartTime = startTime ?? 0 };
         }
     }
 }

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

@@ -495,17 +495,20 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             AddUntilStep("wait for song select", () => this.ChildrenOfType<MultiplayerMatchSongSelect>().FirstOrDefault()?.BeatmapSetsLoaded == true);
 
-            AddAssert("Mods match current item", () => SelectedMods.Value.Select(m => m.Acronym).SequenceEqual(multiplayerClient.Room.AsNonNull().Playlist.First().RequiredMods.Select(m => m.Acronym)));
+            AddAssert("Mods match current item",
+                () => SelectedMods.Value.Select(m => m.Acronym).SequenceEqual(multiplayerClient.Room.AsNonNull().Playlist.First().RequiredMods.Select(m => m.Acronym)));
 
             AddStep("Switch required mods", () => ((MultiplayerMatchSongSelect)multiplayerComponents.MultiplayerScreen.CurrentSubScreen).Mods.Value = new Mod[] { new OsuModDoubleTime() });
 
-            AddAssert("Mods don't match current item", () => !SelectedMods.Value.Select(m => m.Acronym).SequenceEqual(multiplayerClient.Room.AsNonNull().Playlist.First().RequiredMods.Select(m => m.Acronym)));
+            AddAssert("Mods don't match current item",
+                () => !SelectedMods.Value.Select(m => m.Acronym).SequenceEqual(multiplayerClient.Room.AsNonNull().Playlist.First().RequiredMods.Select(m => m.Acronym)));
 
             AddStep("start match externally", () => multiplayerClient.StartMatch().WaitSafely());
 
             AddUntilStep("play started", () => multiplayerComponents.CurrentScreen is Player);
 
-            AddAssert("Mods match current item", () => SelectedMods.Value.Select(m => m.Acronym).SequenceEqual(multiplayerClient.Room.AsNonNull().Playlist.First().RequiredMods.Select(m => m.Acronym)));
+            AddAssert("Mods match current item",
+                () => SelectedMods.Value.Select(m => m.Acronym).SequenceEqual(multiplayerClient.Room.AsNonNull().Playlist.First().RequiredMods.Select(m => m.Acronym)));
         }
 
         [Test]
@@ -665,6 +668,41 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddUntilStep("wait for results", () => multiplayerComponents.CurrentScreen is ResultsScreen);
         }
 
+        [Test]
+        public void TestGameplayDoesntStartWithNonLoadedUser()
+        {
+            createRoom(() => new Room
+            {
+                Name = { Value = "Test Room" },
+                Playlist =
+                {
+                    new PlaylistItem(beatmaps.GetWorkingBeatmap(importedSet.Beatmaps.First(b => b.Ruleset.OnlineID == 0)).BeatmapInfo)
+                    {
+                        RulesetID = new OsuRuleset().RulesetInfo.OnlineID,
+                    }
+                }
+            });
+
+            pressReadyButton();
+
+            AddStep("join other user and ready", () =>
+            {
+                multiplayerClient.AddUser(new APIUser { Id = 1234 });
+                multiplayerClient.ChangeUserState(1234, MultiplayerUserState.Ready);
+            });
+
+            AddStep("start match", () =>
+            {
+                multiplayerClient.StartMatch();
+            });
+
+            AddUntilStep("wait for player", () => multiplayerComponents.CurrentScreen is Player);
+
+            AddWaitStep("wait some", 20);
+
+            AddAssert("ensure gameplay hasn't started", () => this.ChildrenOfType<GameplayClockContainer>().SingleOrDefault()?.IsRunning == false);
+        }
+
         [Test]
         public void TestRoomSettingsReQueriedWhenJoiningRoom()
         {

osu.Game.Tests/Visual/Navigation/TestSceneOsuGame.cs

@@ -37,7 +37,7 @@ namespace osu.Game.Tests.Visual.Navigation
             typeof(OsuLogo),
             typeof(IdleTracker),
             typeof(OnScreenDisplay),
-            typeof(NotificationOverlay),
+            typeof(INotificationOverlay),
             typeof(BeatmapListingOverlay),
             typeof(DashboardOverlay),
             typeof(NewsOverlay),
@@ -49,7 +49,7 @@ namespace osu.Game.Tests.Visual.Navigation
             typeof(LoginOverlay),
             typeof(MusicController),
             typeof(AccountCreationOverlay),
-            typeof(DialogOverlay),
+            typeof(IDialogOverlay),
             typeof(ScreenshotManager)
         };
 

osu.Game.Tests/Visual/Navigation/TestScenePerformFromScreen.cs

@@ -5,6 +5,7 @@ using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Extensions;
+using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Screens;
 using osu.Framework.Testing;
@@ -113,12 +114,12 @@ namespace osu.Game.Tests.Visual.Navigation
             AddAssert("did not perform", () => !actionPerformed);
             AddAssert("only one exit attempt", () => blocker.ExitAttempts == 1);
 
-            AddUntilStep("wait for dialog display", () => Game.Dependencies.Get<DialogOverlay>().IsLoaded);
+            waitForDialogOverlayLoad();
 
             if (confirmed)
             {
                 AddStep("accept dialog", () => InputManager.Key(Key.Number1));
-                AddUntilStep("wait for dialog dismissed", () => Game.Dependencies.Get<DialogOverlay>().CurrentDialog == null);
+                AddUntilStep("wait for dialog dismissed", () => Game.Dependencies.Get<IDialogOverlay>().CurrentDialog == null);
                 AddUntilStep("did perform", () => actionPerformed);
             }
             else
@@ -145,7 +146,7 @@ namespace osu.Game.Tests.Visual.Navigation
 
             AddWaitStep("wait a bit", 10);
 
-            AddUntilStep("wait for dialog display", () => Game.Dependencies.Get<DialogOverlay>().IsLoaded);
+            waitForDialogOverlayLoad();
 
             AddAssert("screen didn't change", () => Game.ScreenStack.CurrentScreen == blocker2);
             AddAssert("did not perform", () => !actionPerformed);
@@ -171,6 +172,48 @@ namespace osu.Game.Tests.Visual.Navigation
             }
         }
 
+        [TestCase(true)]
+        [TestCase(false)]
+        public void TestPerformBlockedByDialogSubScreen(bool confirm)
+        {
+            TestScreenWithNestedStack screenWithNestedStack = null;
+
+            PushAndConfirm(() => screenWithNestedStack = new TestScreenWithNestedStack());
+
+            AddAssert("wait for nested screen", () => screenWithNestedStack.SubScreenStack.CurrentScreen == screenWithNestedStack.Blocker);
+
+            AddStep("try to perform", () => Game.PerformFromScreen(_ => actionPerformed = true));
+
+            AddUntilStep("wait for dialog", () => screenWithNestedStack.Blocker.ExitAttempts == 1);
+
+            AddWaitStep("wait a bit", 10);
+
+            waitForDialogOverlayLoad();
+
+            AddAssert("screen didn't change", () => Game.ScreenStack.CurrentScreen == screenWithNestedStack);
+            AddAssert("nested screen didn't change", () => screenWithNestedStack.SubScreenStack.CurrentScreen == screenWithNestedStack.Blocker);
+
+            AddAssert("did not perform", () => !actionPerformed);
+
+            AddAssert("only one exit attempt", () => screenWithNestedStack.Blocker.ExitAttempts == 1);
+
+            if (confirm)
+            {
+                AddStep("accept dialog", () => InputManager.Key(Key.Number1));
+                AddAssert("nested screen changed", () => screenWithNestedStack.SubScreenStack.CurrentScreen != screenWithNestedStack.Blocker);
+                AddUntilStep("did perform", () => actionPerformed);
+            }
+            else
+            {
+                AddStep("cancel dialog", () => InputManager.Key(Key.Number2));
+                AddAssert("screen didn't change", () => Game.ScreenStack.CurrentScreen == screenWithNestedStack);
+                AddAssert("nested screen didn't change", () => screenWithNestedStack.SubScreenStack.CurrentScreen == screenWithNestedStack.Blocker);
+                AddAssert("did not perform", () => !actionPerformed);
+            }
+        }
+
+        private void waitForDialogOverlayLoad() => AddUntilStep("wait for dialog overlay loaded", () => ((Drawable)Game.Dependencies.Get<IDialogOverlay>()).IsLoaded);
+
         private void importAndWaitForSongSelect()
         {
             AddStep("import beatmap", () => BeatmapImportHelper.LoadQuickOszIntoOsu(Game).WaitSafely());
@@ -181,13 +224,13 @@ namespace osu.Game.Tests.Visual.Navigation
         public class DialogBlockingScreen : OsuScreen
         {
             [Resolved]
-            private DialogOverlay dialogOverlay { get; set; }
+            private IDialogOverlay dialogOverlay { get; set; }
 
             private int dialogDisplayCount;
 
             public int ExitAttempts { get; private set; }
 
-            public override bool OnExiting(IScreen next)
+            public override bool OnExiting(ScreenExitEvent e)
             {
                 ExitAttempts++;
 
@@ -197,7 +240,32 @@ namespace osu.Game.Tests.Visual.Navigation
                     return true;
                 }
 
-                return base.OnExiting(next);
+                return base.OnExiting(e);
+            }
+        }
+
+        public class TestScreenWithNestedStack : OsuScreen, IHasSubScreenStack
+        {
+            public DialogBlockingScreen Blocker { get; private set; }
+
+            public ScreenStack SubScreenStack { get; } = new ScreenStack();
+
+            public TestScreenWithNestedStack()
+            {
+                AddInternal(SubScreenStack);
+
+                SubScreenStack.Push(Blocker = new DialogBlockingScreen());
+            }
+
+            public override bool OnExiting(ScreenExitEvent e)
+            {
+                if (SubScreenStack.CurrentScreen != null)
+                {
+                    SubScreenStack.CurrentScreen.Exit();
+                    return true;
+                }
+
+                return base.OnExiting(e);
             }
         }
     }

osu.Game.Tests/Visual/Navigation/TestSceneScreenNavigation.cs

@@ -6,6 +6,7 @@ using System.Linq;
 using NUnit.Framework;
 using osu.Framework.Allocation;
 using osu.Framework.Extensions;
+using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.UserInterface;
 using osu.Framework.Screens;
@@ -200,10 +201,10 @@ namespace osu.Game.Tests.Visual.Navigation
 
             AddStep("choose clear all scores", () => InputManager.Key(Key.Number4));
 
-            AddUntilStep("wait for dialog display", () => Game.Dependencies.Get<DialogOverlay>().IsLoaded);
+            AddUntilStep("wait for dialog display", () => ((Drawable)Game.Dependencies.Get<IDialogOverlay>()).IsLoaded);
-            AddUntilStep("wait for dialog", () => Game.Dependencies.Get<DialogOverlay>().CurrentDialog != null);
+            AddUntilStep("wait for dialog", () => Game.Dependencies.Get<IDialogOverlay>().CurrentDialog != null);
             AddStep("confirm deletion", () => InputManager.Key(Key.Number1));
-            AddUntilStep("wait for dialog dismissed", () => Game.Dependencies.Get<DialogOverlay>().CurrentDialog == null);
+            AddUntilStep("wait for dialog dismissed", () => Game.Dependencies.Get<IDialogOverlay>().CurrentDialog == null);
 
             AddUntilStep("ensure score is pending deletion", () => Game.Realm.Run(r => r.Find<ScoreInfo>(score.ID)?.DeletePending == true));
 
@@ -246,10 +247,10 @@ namespace osu.Game.Tests.Visual.Navigation
                 InputManager.Click(MouseButton.Left);
             });
 
-            AddUntilStep("wait for dialog display", () => Game.Dependencies.Get<DialogOverlay>().IsLoaded);
+            AddUntilStep("wait for dialog display", () => ((Drawable)Game.Dependencies.Get<IDialogOverlay>()).IsLoaded);
-            AddUntilStep("wait for dialog", () => Game.Dependencies.Get<DialogOverlay>().CurrentDialog != null);
+            AddUntilStep("wait for dialog", () => Game.Dependencies.Get<IDialogOverlay>().CurrentDialog != null);
             AddStep("confirm deletion", () => InputManager.Key(Key.Number1));
-            AddUntilStep("wait for dialog dismissed", () => Game.Dependencies.Get<DialogOverlay>().CurrentDialog == null);
+            AddUntilStep("wait for dialog dismissed", () => Game.Dependencies.Get<IDialogOverlay>().CurrentDialog == null);
 
             AddUntilStep("ensure score is pending deletion", () => Game.Realm.Run(r => r.Find<ScoreInfo>(score.ID)?.DeletePending == true));
 

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

@@ -0,0 +1,188 @@
+// 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 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.Framework.Utils;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Online.Chat;
+using osu.Game.Overlays;
+using osu.Game.Overlays.Chat.ChannelList;
+
+namespace osu.Game.Tests.Visual.Online
+{
+    [TestFixture]
+    public class TestSceneChannelList : OsuTestScene
+    {
+        [Cached]
+        private readonly OverlayColourProvider colourProvider = new OverlayColourProvider(OverlayColourScheme.Pink);
+
+        [Cached]
+        private readonly Bindable<Channel> selected = new Bindable<Channel>();
+
+        private OsuSpriteText selectorText;
+        private OsuSpriteText selectedText;
+        private OsuSpriteText leaveText;
+        private ChannelList channelList;
+
+        [SetUp]
+        public void SetUp()
+        {
+            Schedule(() =>
+            {
+                Child = new GridContainer
+                {
+                    Anchor = Anchor.Centre,
+                    Origin = Anchor.Centre,
+                    RelativeSizeAxes = Axes.Both,
+                    Height = 0.7f,
+                    RowDimensions = new[]
+                    {
+                        new Dimension(GridSizeMode.Absolute, 20),
+                        new Dimension(GridSizeMode.Absolute, 20),
+                        new Dimension(GridSizeMode.Absolute, 20),
+                        new Dimension(),
+                    },
+                    Content = new[]
+                    {
+                        new Drawable[]
+                        {
+                            selectorText = new OsuSpriteText
+                            {
+                                Anchor = Anchor.TopCentre,
+                                Origin = Anchor.TopCentre,
+                            },
+                        },
+                        new Drawable[]
+                        {
+                            selectedText = new OsuSpriteText
+                            {
+                                Anchor = Anchor.TopCentre,
+                                Origin = Anchor.TopCentre,
+                            },
+                        },
+                        new Drawable[]
+                        {
+                            leaveText = new OsuSpriteText
+                            {
+                                Anchor = Anchor.TopCentre,
+                                Origin = Anchor.TopCentre,
+                            },
+                        },
+                        new Drawable[]
+                        {
+                            channelList = new ChannelList
+                            {
+                                Anchor = Anchor.TopCentre,
+                                Origin = Anchor.TopCentre,
+                                RelativeSizeAxes = Axes.Y,
+                                Width = 190,
+                            },
+                        },
+                    },
+                };
+
+                channelList.OnRequestSelect += channel =>
+                {
+                    channelList.SelectorActive.Value = false;
+                    selected.Value = channel;
+                };
+
+                channelList.OnRequestLeave += channel =>
+                {
+                    leaveText.Text = $"OnRequestLeave: {channel.Name}";
+                    leaveText.FadeOutFromOne(1000, Easing.InQuint);
+                    selected.Value = null;
+                    channelList.RemoveChannel(channel);
+                };
+
+                channelList.SelectorActive.BindValueChanged(change =>
+                {
+                    selectorText.Text = $"Channel Selector Active: {change.NewValue}";
+                    selected.Value = null;
+                }, true);
+
+                selected.BindValueChanged(change =>
+                {
+                    selectedText.Text = $"Selected Channel: {change.NewValue?.Name ?? "[null]"}";
+                }, true);
+            });
+        }
+
+        [SetUpSteps]
+        public void SetUpSteps()
+        {
+            AddStep("Add Public Channels", () =>
+            {
+                for (int i = 0; i < 10; i++)
+                    channelList.AddChannel(createRandomPublicChannel());
+            });
+
+            AddStep("Add Private Channels", () =>
+            {
+                for (int i = 0; i < 10; i++)
+                    channelList.AddChannel(createRandomPrivateChannel());
+            });
+        }
+
+        [Test]
+        public void TestVisual()
+        {
+            AddStep("Unread Selected", () =>
+            {
+                if (selected.Value != null)
+                    channelList.GetItem(selected.Value).Unread.Value = true;
+            });
+
+            AddStep("Read Selected", () =>
+            {
+                if (selected.Value != null)
+                    channelList.GetItem(selected.Value).Unread.Value = false;
+            });
+
+            AddStep("Add Mention Selected", () =>
+            {
+                if (selected.Value != null)
+                    channelList.GetItem(selected.Value).Mentions.Value++;
+            });
+
+            AddStep("Add 98 Mentions Selected", () =>
+            {
+                if (selected.Value != null)
+                    channelList.GetItem(selected.Value).Mentions.Value += 98;
+            });
+
+            AddStep("Clear Mentions Selected", () =>
+            {
+                if (selected.Value != null)
+                    channelList.GetItem(selected.Value).Mentions.Value = 0;
+            });
+        }
+
+        private Channel createRandomPublicChannel()
+        {
+            int id = RNG.Next(0, 10000);
+            return new Channel
+            {
+                Name = $"#channel-{id}",
+                Type = ChannelType.Public,
+                Id = id,
+            };
+        }
+
+        private Channel createRandomPrivateChannel()
+        {
+            int id = RNG.Next(0, 10000);
+            return new Channel(new APIUser
+            {
+                Id = id,
+                Username = $"test user {id}",
+            });
+        }
+    }
+}

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

@@ -1,163 +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 NUnit.Framework;
-using System.Collections.Generic;
-using System.Linq;
-using osu.Framework.Allocation;
-using osu.Framework.Bindables;
-using osu.Framework.Graphics;
-using osu.Framework.Graphics.Containers;
-using osu.Framework.Graphics.Shapes;
-using osu.Game.Graphics.Sprites;
-using osu.Game.Online.API.Requests.Responses;
-using osu.Game.Online.Chat;
-using osu.Game.Overlays;
-using osu.Game.Overlays.Chat.ChannelList;
-using osuTK;
-
-namespace osu.Game.Tests.Visual.Online
-{
-    [TestFixture]
-    public class TestSceneChannelListItem : OsuTestScene
-    {
-        [Cached]
-        private readonly OverlayColourProvider colourProvider = new OverlayColourProvider(OverlayColourScheme.Pink);
-
-        [Cached]
-        private readonly Bindable<Channel> selected = new Bindable<Channel>();
-
-        private static readonly List<Channel> channels = new List<Channel>
-        {
-            createPublicChannel("#public-channel"),
-            createPublicChannel("#public-channel-long-name"),
-            createPrivateChannel("test user", 2),
-            createPrivateChannel("test user long name", 3),
-        };
-
-        private readonly Dictionary<Channel, ChannelListItem> channelMap = new Dictionary<Channel, ChannelListItem>();
-
-        private FillFlowContainer flow;
-        private OsuSpriteText selectedText;
-        private OsuSpriteText leaveText;
-
-        [SetUp]
-        public void SetUp()
-        {
-            Schedule(() =>
-            {
-                foreach (var item in channelMap.Values)
-                    item.Expire();
-
-                channelMap.Clear();
-
-                Child = new FillFlowContainer
-                {
-                    Direction = FillDirection.Vertical,
-                    Anchor = Anchor.Centre,
-                    Origin = Anchor.Centre,
-                    AutoSizeAxes = Axes.Both,
-                    Spacing = new Vector2(10),
-                    Children = new Drawable[]
-                    {
-                        selectedText = new OsuSpriteText
-                        {
-                            Anchor = Anchor.TopCentre,
-                            Origin = Anchor.TopCentre,
-                        },
-                        leaveText = new OsuSpriteText
-                        {
-                            Anchor = Anchor.TopCentre,
-                            Origin = Anchor.TopCentre,
-                            Height = 16,
-                            AlwaysPresent = true,
-                        },
-                        new Container
-                        {
-                            Anchor = Anchor.TopCentre,
-                            Origin = Anchor.TopCentre,
-                            AutoSizeAxes = Axes.Y,
-                            Width = 190,
-                            Children = new Drawable[]
-                            {
-                                new Box
-                                {
-                                    RelativeSizeAxes = Axes.Both,
-                                    Colour = colourProvider.Background6,
-                                },
-                                flow = new FillFlowContainer
-                                {
-                                    Direction = FillDirection.Vertical,
-                                    RelativeSizeAxes = Axes.X,
-                                    AutoSizeAxes = Axes.Y,
-                                },
-                            },
-                        },
-                    },
-                };
-
-                selected.BindValueChanged(change =>
-                {
-                    selectedText.Text = $"Selected Channel: {change.NewValue?.Name ?? "[null]"}";
-                }, true);
-
-                foreach (var channel in channels)
-                {
-                    var item = new ChannelListItem(channel);
-                    flow.Add(item);
-                    channelMap.Add(channel, item);
-                    item.OnRequestSelect += c => selected.Value = c;
-                    item.OnRequestLeave += leaveChannel;
-                }
-            });
-        }
-
-        [Test]
-        public void TestVisual()
-        {
-            AddStep("Select second item", () => selected.Value = channels.Skip(1).First());
-
-            AddStep("Unread Selected", () =>
-            {
-                if (selected.Value != null)
-                    channelMap[selected.Value].Unread.Value = true;
-            });
-
-            AddStep("Read Selected", () =>
-            {
-                if (selected.Value != null)
-                    channelMap[selected.Value].Unread.Value = false;
-            });
-
-            AddStep("Add Mention Selected", () =>
-            {
-                if (selected.Value != null)
-                    channelMap[selected.Value].Mentions.Value++;
-            });
-
-            AddStep("Add 98 Mentions Selected", () =>
-            {
-                if (selected.Value != null)
-                    channelMap[selected.Value].Mentions.Value += 98;
-            });
-
-            AddStep("Clear Mentions Selected", () =>
-            {
-                if (selected.Value != null)
-                    channelMap[selected.Value].Mentions.Value = 0;
-            });
-        }
-
-        private void leaveChannel(Channel channel)
-        {
-            leaveText.Text = $"OnRequestLeave: {channel.Name}";
-            leaveText.FadeOutFromOne(1000, Easing.InQuint);
-        }
-
-        private static Channel createPublicChannel(string name) =>
-            new Channel { Name = name, Type = ChannelType.Public, Id = 1234 };
-
-        private static Channel createPrivateChannel(string username, int id)
-            => new Channel(new APIUser { Id = id, Username = username });
-    }
-}

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

@@ -49,7 +49,7 @@ namespace osu.Game.Tests.Visual.Online
             Dependencies.Cache(chatManager);
 
             Dependencies.Cache(new ChatOverlay());
-            Dependencies.Cache(dialogOverlay);
+            Dependencies.CacheAs<IDialogOverlay>(dialogOverlay);
         }
 
         [SetUp]

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

@@ -200,7 +200,7 @@ namespace osu.Game.Tests.Visual.Online
             [Cached]
             public ChannelManager ChannelManager { get; } = new ChannelManager();
 
-            [Cached]
+            [Cached(typeof(INotificationOverlay))]
             public NotificationOverlay NotificationOverlay { get; } = new NotificationOverlay
             {
                 Anchor = Anchor.TopRight,

osu.Game.Tests/Visual/Settings/TestSceneMigrationScreens.cs

@@ -14,7 +14,7 @@ namespace osu.Game.Tests.Visual.Settings
 {
     public class TestSceneMigrationScreens : ScreenTestScene
     {
-        [Cached]
+        [Cached(typeof(INotificationOverlay))]
         private readonly NotificationOverlay notifications;
 
         public TestSceneMigrationScreens()

osu.Game.Tests/Visual/Settings/TestSceneSettingsPanel.cs

@@ -121,7 +121,7 @@ namespace osu.Game.Tests.Visual.Settings
                 Depth = -1
             });
 
-            Dependencies.Cache(dialogOverlay);
+            Dependencies.CacheAs<IDialogOverlay>(dialogOverlay);
         }
     }
 }

osu.Game.Tests/Visual/SongSelect/TestSceneAdvancedStats.cs

@@ -10,6 +10,7 @@ using osu.Framework.Graphics.Sprites;
 using osu.Framework.Testing;
 using osu.Game.Beatmaps;
 using osu.Game.Graphics;
+using osu.Game.Resources.Localisation.Web;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Mods;
 using osu.Game.Rulesets.Osu.Mods;
@@ -55,7 +56,7 @@ namespace osu.Game.Tests.Visual.SongSelect
 
             AddStep("no mods selected", () => SelectedMods.Value = Array.Empty<Mod>());
 
-            AddAssert("first bar text is Circle Size", () => advancedStats.ChildrenOfType<SpriteText>().First().Text == "Circle Size");
+            AddAssert("first bar text is correct", () => advancedStats.ChildrenOfType<SpriteText>().First().Text == BeatmapsetsStrings.ShowStatsCs);
             AddAssert("circle size bar is white", () => barIsWhite(advancedStats.FirstValue));
             AddAssert("HP drain bar is white", () => barIsWhite(advancedStats.HpDrain));
             AddAssert("accuracy bar is white", () => barIsWhite(advancedStats.Accuracy));
@@ -78,7 +79,7 @@ namespace osu.Game.Tests.Visual.SongSelect
                 StarRating = 8
             });
 
-            AddAssert("first bar text is Key Count", () => advancedStats.ChildrenOfType<SpriteText>().First().Text == "Key Count");
+            AddAssert("first bar text is correct", () => advancedStats.ChildrenOfType<SpriteText>().First().Text == BeatmapsetsStrings.ShowStatsCsMania);
         }
 
         [Test]

osu.Game.Tests/Visual/SongSelect/TestSceneBeatmapLeaderboard.cs

@@ -31,7 +31,7 @@ namespace osu.Game.Tests.Visual.SongSelect
     {
         private readonly FailableLeaderboard leaderboard;
 
-        [Cached]
+        [Cached(typeof(IDialogOverlay))]
         private readonly DialogOverlay dialogOverlay;
 
         private ScoreManager scoreManager;

osu.Game.Tests/Visual/SongSelect/TestSceneUserTopScoreContainer.cs

@@ -19,7 +19,7 @@ namespace osu.Game.Tests.Visual.SongSelect
 {
     public class TestSceneUserTopScoreContainer : OsuTestScene
     {
-        [Cached]
+        [Cached(typeof(IDialogOverlay))]
         private readonly DialogOverlay dialogOverlay;
 
         public TestSceneUserTopScoreContainer()

osu.Game.Tests/Visual/TestMultiplayerComponents.cs

@@ -80,10 +80,10 @@ namespace osu.Game.Tests.Visual
 
         public override bool OnBackButton() => (screenStack.CurrentScreen as OsuScreen)?.OnBackButton() ?? base.OnBackButton();
 
-        public override bool OnExiting(IScreen next)
+        public override bool OnExiting(ScreenExitEvent e)
         {
             if (screenStack.CurrentScreen == null)
-                return base.OnExiting(next);
+                return base.OnExiting(e);
 
             screenStack.Exit();
             return true;

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

@@ -42,7 +42,7 @@ namespace osu.Game.Tests.Visual.UserInterface
 
         private BeatmapInfo beatmapInfo;
 
-        [Cached]
+        [Cached(typeof(IDialogOverlay))]
         private readonly DialogOverlay dialogOverlay;
 
         public TestSceneDeleteLocalScore()

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

@@ -23,7 +23,7 @@ namespace osu.Game.Tests.Visual.UserInterface
         [Resolved]
         private RulesetStore rulesetStore { get; set; }
 
-        private ModSelectScreen modSelectScreen;
+        private UserModSelectScreen modSelectScreen;
 
         [SetUpSteps]
         public void SetUpSteps()
@@ -35,7 +35,7 @@ namespace osu.Game.Tests.Visual.UserInterface
 
         private void createScreen()
         {
-            AddStep("create screen", () => Child = modSelectScreen = new ModSelectScreen
+            AddStep("create screen", () => Child = modSelectScreen = new UserModSelectScreen
             {
                 RelativeSizeAxes = Axes.Both,
                 State = { Value = Visibility.Visible },

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

@@ -10,19 +10,19 @@ using osu.Game.Overlays;
 namespace osu.Game.Tests.Visual.UserInterface
 {
     [TestFixture]
-    public class TestScenePopupScreenTitle : OsuTestScene
+    public class TestSceneShearedOverlayHeader : OsuTestScene
     {
         [Cached]
         private OverlayColourProvider colourProvider = new OverlayColourProvider(OverlayColourScheme.Green);
 
         [Test]
-        public void TestPopupScreenTitle()
+        public void TestShearedOverlayHeader()
         {
             AddStep("create content", () =>
             {
-                Child = new PopupScreenTitle
+                Child = new ShearedOverlayHeader
                 {
-                    Title = "Popup Screen Title",
+                    Title = "Sheared overlay header",
                     Description = string.Join(" ", Enumerable.Repeat("This is a description.", 20)),
                     Close = () => { }
                 };
@@ -34,9 +34,9 @@ namespace osu.Game.Tests.Visual.UserInterface
         {
             AddStep("create content", () =>
             {
-                Child = new PopupScreenTitle
+                Child = new ShearedOverlayHeader
                 {
-                    Title = "Popup Screen Title",
+                    Title = "Sheared overlay header",
                     Description = "This is a description."
                 };
             });

osu.Game/Beatmaps/BeatmapStatistic.cs

@@ -3,6 +3,7 @@
 
 using System;
 using osu.Framework.Graphics;
+using osu.Framework.Localisation;
 
 namespace osu.Game.Beatmaps
 {
@@ -14,6 +15,6 @@ namespace osu.Game.Beatmaps
         public Func<Drawable> CreateIcon;
 
         public string Content;
-        public string Name;
+        public LocalisableString Name;
     }
 }

osu.Game/Beatmaps/Drawables/BeatmapDownloadButton.cs

@@ -12,6 +12,7 @@ using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Online;
 using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Beatmaps.Drawables
 {
@@ -104,7 +105,7 @@ namespace osu.Game.Beatmaps.Drawables
                         if ((beatmapSet as IBeatmapSetOnlineInfo)?.Availability.DownloadDisabled == true)
                         {
                             button.Enabled.Value = false;
-                            button.TooltipText = "this beatmap is currently not available for download.";
+                            button.TooltipText = BeatmapsetsStrings.AvailabilityDisabled;
                         }
 
                         break;

osu.Game/Collections/DrawableCollectionListItem.cs

@@ -158,7 +158,7 @@ namespace osu.Game.Collections
             public Func<Vector2, bool> IsTextBoxHovered;
 
             [Resolved(CanBeNull = true)]
-            private DialogOverlay dialogOverlay { get; set; }
+            private IDialogOverlay dialogOverlay { get; set; }
 
             [Resolved(CanBeNull = true)]
             private CollectionManager collectionManager { get; set; }

osu.Game/Database/EFToRealmMigrator.cs

@@ -52,7 +52,7 @@ namespace osu.Game.Database
         private OsuConfigManager config { get; set; } = null!;
 
         [Resolved]
-        private NotificationOverlay notificationOverlay { get; set; } = null!;
+        private INotificationOverlay notificationOverlay { get; set; } = null!;
 
         [Resolved]
         private OsuGame game { get; set; } = null!;

osu.Game/Database/LegacyImportManager.cs

@@ -40,7 +40,7 @@ namespace osu.Game.Database
         private OsuGame game { get; set; }
 
         [Resolved]
-        private DialogOverlay dialogOverlay { get; set; }
+        private IDialogOverlay dialogOverlay { get; set; }
 
         [Resolved(CanBeNull = true)]
         private DesktopGameHost desktopGameHost { get; set; }

osu.Game/Graphics/Containers/ScalingContainer.cs

@@ -209,7 +209,7 @@ namespace osu.Game.Graphics.Containers
         {
             protected override bool AllowStoryboardBackground => false;
 
-            public override void OnEntering(IScreen last)
+            public override void OnEntering(ScreenTransitionEvent e)
             {
                 this.FadeInFromZero(4000, Easing.OutQuint);
             }

osu.Game/Graphics/ScreenshotManager.cs

@@ -43,7 +43,7 @@ namespace osu.Game.Graphics
         private Storage storage;
 
         [Resolved]
-        private NotificationOverlay notificationOverlay { get; set; }
+        private INotificationOverlay notificationOverlay { get; set; }
 
         private Sample shutter;
 

osu.Game/Graphics/UserInterface/OsuMenuItem.cs

@@ -3,6 +3,7 @@
 
 using System;
 using osu.Framework.Graphics.UserInterface;
+using osu.Framework.Localisation;
 
 namespace osu.Game.Graphics.UserInterface
 {
@@ -15,7 +16,7 @@ namespace osu.Game.Graphics.UserInterface
         {
         }
 
-        public OsuMenuItem(string text, MenuItemType type, Action action)
+        public OsuMenuItem(LocalisableString text, MenuItemType type, Action action)
             : base(text, action)
         {
             Type = type;

osu.Game/Graphics/UserInterface/PageSelector/PageSelector.cs

@@ -5,6 +5,7 @@ using System;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics;
 using osu.Framework.Bindables;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Graphics.UserInterface.PageSelector
 {
@@ -29,7 +30,7 @@ namespace osu.Game.Graphics.UserInterface.PageSelector
                 Direction = FillDirection.Horizontal,
                 Children = new Drawable[]
                 {
-                    previousPageButton = new PageSelectorPrevNextButton(false, "prev")
+                    previousPageButton = new PageSelectorPrevNextButton(false, CommonStrings.PaginationPrevious)
                     {
                         Action = () => CurrentPage.Value -= 1,
                     },
@@ -38,7 +39,7 @@ namespace osu.Game.Graphics.UserInterface.PageSelector
                         AutoSizeAxes = Axes.Both,
                         Direction = FillDirection.Horizontal,
                     },
-                    nextPageButton = new PageSelectorPrevNextButton(true, "next")
+                    nextPageButton = new PageSelectorPrevNextButton(true, CommonStrings.PaginationNext)
                     {
                         Action = () => CurrentPage.Value += 1
                     }

osu.Game/Graphics/UserInterface/PageSelector/PageSelectorPrevNextButton.cs

@@ -2,9 +2,11 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Allocation;
+using osu.Framework.Extensions.LocalisationExtensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Graphics.Sprites;
+using osu.Framework.Localisation;
 using osu.Game.Graphics.Sprites;
 using osuTK;
 
@@ -13,12 +15,12 @@ namespace osu.Game.Graphics.UserInterface.PageSelector
     public class PageSelectorPrevNextButton : PageSelectorButton
     {
         private readonly bool rightAligned;
-        private readonly string text;
+        private readonly LocalisableString text;
 
         private SpriteIcon icon;
         private OsuSpriteText name;
 
-        public PageSelectorPrevNextButton(bool rightAligned, string text)
+        public PageSelectorPrevNextButton(bool rightAligned, LocalisableString text)
         {
             this.rightAligned = rightAligned;
             this.text = text;

osu.Game/Graphics/UserInterface/SearchTextBox.cs

@@ -5,6 +5,7 @@ using osu.Framework.Graphics;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Input;
 using osu.Framework.Input.Events;
+using osu.Game.Resources.Localisation.Web;
 using osuTK;
 using osuTK.Input;
 
@@ -27,7 +28,7 @@ namespace osu.Game.Graphics.UserInterface
             });
 
             TextFlow.Padding = new MarginPadding { Right = 35 };
-            PlaceholderText = "type to search";
+            PlaceholderText = HomeStrings.SearchPlaceholder;
         }
 
         public override bool OnPressed(KeyBindingPressEvent<PlatformAction> e)

osu.Game/Graphics/UserInterface/ShearedOverlayHeader.cs

@@ -19,8 +19,10 @@ using osuTK;
 
 namespace osu.Game.Graphics.UserInterface
 {
-    public class PopupScreenTitle : CompositeDrawable
+    public class ShearedOverlayHeader : CompositeDrawable
     {
+        public const float HEIGHT = main_area_height + 2 * corner_radius;
+
         public LocalisableString Title
         {
             set => titleSpriteText.Text = value;
@@ -48,7 +50,7 @@ namespace osu.Game.Graphics.UserInterface
         private readonly OsuTextFlowContainer descriptionText;
         private readonly IconButton closeButton;
 
-        public PopupScreenTitle()
+        public ShearedOverlayHeader()
         {
             RelativeSizeAxes = Axes.X;
             AutoSizeAxes = Axes.Y;
@@ -67,7 +69,7 @@ namespace osu.Game.Graphics.UserInterface
                     underlayContainer = new Container
                     {
                         RelativeSizeAxes = Axes.X,
-                        Height = main_area_height + 2 * corner_radius,
+                        Height = HEIGHT,
                         CornerRadius = corner_radius,
                         Masking = true,
                         BorderThickness = 2,

osu.Game/Graphics/UserInterface/ShowMoreButton.cs

@@ -11,7 +11,9 @@ using osu.Game.Graphics.Sprites;
 using osu.Game.Overlays;
 using osuTK;
 using System.Collections.Generic;
+using osu.Framework.Extensions.LocalisationExtensions;
 using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Graphics.UserInterface
 {
@@ -80,7 +82,7 @@ namespace osu.Game.Graphics.UserInterface
                             Anchor = Anchor.Centre,
                             Origin = Anchor.Centre,
                             Font = OsuFont.GetFont(size: 12, weight: FontWeight.SemiBold),
-                            Text = "show more".ToUpper(),
+                            Text = CommonStrings.ButtonsShowMore.ToUpper(),
                         },
                         rightIcon = new ChevronIcon
                         {

osu.Game/Graphics/UserInterfaceV2/ColourDisplay.cs

@@ -14,6 +14,7 @@ using osu.Framework.Localisation;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Graphics.UserInterface;
+using osu.Game.Resources.Localisation.Web;
 using osuTK;
 
 namespace osu.Game.Graphics.UserInterfaceV2
@@ -139,7 +140,7 @@ namespace osu.Game.Graphics.UserInterfaceV2
 
             public MenuItem[] ContextMenuItems => new MenuItem[]
             {
-                new OsuMenuItem("Delete", MenuItemType.Destructive, () => DeleteRequested?.Invoke())
+                new OsuMenuItem(CommonStrings.ButtonsDelete, MenuItemType.Destructive, () => DeleteRequested?.Invoke())
             };
         }
     }

osu.Game/Localisation/CommonStrings.cs

@@ -9,16 +9,6 @@ namespace osu.Game.Localisation
     {
         private const string prefix = @"osu.Game.Resources.Localisation.Common";
 
-        /// <summary>
-        /// "Cancel"
-        /// </summary>
-        public static LocalisableString Cancel => new TranslatableString(getKey(@"cancel"), @"Cancel");
-
-        /// <summary>
-        /// "Clear"
-        /// </summary>
-        public static LocalisableString Clear => new TranslatableString(getKey(@"clear"), @"Clear");
-
         /// <summary>
         /// "Enabled"
         /// </summary>

osu.Game/Localisation/DebugLocalisationStore.cs

@@ -0,0 +1,30 @@
+// 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.Globalization;
+using System.IO;
+using System.Threading;
+using System.Threading.Tasks;
+using osu.Framework.Localisation;
+
+namespace osu.Game.Localisation
+{
+    public class DebugLocalisationStore : ILocalisationStore
+    {
+        public string Get(string lookup) => $@"[[{lookup.Substring(lookup.LastIndexOf('.') + 1)}]]";
+
+        public Task<string> GetAsync(string lookup, CancellationToken cancellationToken = default) => Task.FromResult(Get(lookup));
+
+        public Stream GetStream(string name) => throw new NotImplementedException();
+
+        public IEnumerable<string> GetAvailableResources() => throw new NotImplementedException();
+
+        public CultureInfo EffectiveCulture { get; } = CultureInfo.CurrentCulture;
+
+        public void Dispose()
+        {
+        }
+    }
+}

osu.Game/Localisation/Language.cs

@@ -110,6 +110,11 @@ namespace osu.Game.Localisation
         // zh_hk,
 
         [Description(@"繁體中文（台灣）")]
-        zh_tw
+        zh_hant,
+
+#if DEBUG
+        [Description(@"Debug (show raw keys)")]
+        debug
+#endif
     }
 }

osu.Game/Online/API/Requests/GetUserBeatmapsRequest.cs

@@ -13,8 +13,8 @@ namespace osu.Game.Online.API.Requests
 
         private readonly BeatmapSetType type;
 
-        public GetUserBeatmapsRequest(long userId, BeatmapSetType type, int page = 0, int itemsPerPage = 6)
+        public GetUserBeatmapsRequest(long userId, BeatmapSetType type, PaginationParameters pagination)
-            : base(page, itemsPerPage)
+            : base(pagination)
         {
             this.userId = userId;
             this.type = type;

osu.Game/Online/API/Requests/GetUserKudosuHistoryRequest.cs

@@ -10,8 +10,8 @@ namespace osu.Game.Online.API.Requests
     {
         private readonly long userId;
 
-        public GetUserKudosuHistoryRequest(long userId, int page = 0, int itemsPerPage = 5)
+        public GetUserKudosuHistoryRequest(long userId, PaginationParameters pagination)
-            : base(page, itemsPerPage)
+            : base(pagination)
         {
             this.userId = userId;
         }

osu.Game/Online/API/Requests/GetUserMostPlayedBeatmapsRequest.cs

@@ -10,8 +10,8 @@ namespace osu.Game.Online.API.Requests
     {
         private readonly long userId;
 
-        public GetUserMostPlayedBeatmapsRequest(long userId, int page = 0, int itemsPerPage = 5)
+        public GetUserMostPlayedBeatmapsRequest(long userId, PaginationParameters pagination)
-            : base(page, itemsPerPage)
+            : base(pagination)
         {
             this.userId = userId;
         }

osu.Game/Online/API/Requests/GetUserRecentActivitiesRequest.cs

@@ -10,8 +10,8 @@ namespace osu.Game.Online.API.Requests
     {
         private readonly long userId;
 
-        public GetUserRecentActivitiesRequest(long userId, int page = 0, int itemsPerPage = 5)
+        public GetUserRecentActivitiesRequest(long userId, PaginationParameters pagination)
-            : base(page, itemsPerPage)
+            : base(pagination)
         {
             this.userId = userId;
         }

osu.Game/Online/API/Requests/GetUserScoresRequest.cs

@@ -14,8 +14,8 @@ namespace osu.Game.Online.API.Requests
         private readonly ScoreType type;
         private readonly RulesetInfo ruleset;
 
-        public GetUserScoresRequest(long userId, ScoreType type, int page = 0, int itemsPerPage = 5, RulesetInfo ruleset = null)
+        public GetUserScoresRequest(long userId, ScoreType type, PaginationParameters pagination, RulesetInfo ruleset = null)
-            : base(page, itemsPerPage)
+            : base(pagination)
         {
             this.userId = userId;
             this.type = type;

osu.Game/Online/API/Requests/PaginatedAPIRequest.cs

@@ -8,21 +8,19 @@ namespace osu.Game.Online.API.Requests
 {
     public abstract class PaginatedAPIRequest<T> : APIRequest<T> where T : class
     {
-        private readonly int page;
+        private readonly PaginationParameters pagination;
-        private readonly int itemsPerPage;
 
-        protected PaginatedAPIRequest(int page, int itemsPerPage)
+        protected PaginatedAPIRequest(PaginationParameters pagination)
         {
-            this.page = page;
+            this.pagination = pagination;
-            this.itemsPerPage = itemsPerPage;
         }
 
         protected override WebRequest CreateWebRequest()
         {
             var req = base.CreateWebRequest();
 
-            req.AddParameter("offset", (page * itemsPerPage).ToString(CultureInfo.InvariantCulture));
+            req.AddParameter("offset", pagination.Offset.ToString(CultureInfo.InvariantCulture));
-            req.AddParameter("limit", itemsPerPage.ToString(CultureInfo.InvariantCulture));
+            req.AddParameter("limit", pagination.Limit.ToString(CultureInfo.InvariantCulture));
 
             return req;
         }

osu.Game/Online/API/Requests/PaginationParameters.cs

@@ -0,0 +1,38 @@
+// 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.
+
+namespace osu.Game.Online.API.Requests
+{
+    /// <summary>
+    /// Represents a pagination data used for <see cref="PaginatedAPIRequest{T}"/>.
+    /// </summary>
+    public readonly struct PaginationParameters
+    {
+        /// <summary>
+        /// The starting point of the request.
+        /// </summary>
+        public int Offset { get; }
+
+        /// <summary>
+        /// The maximum number of items to return in this request.
+        /// </summary>
+        public int Limit { get; }
+
+        public PaginationParameters(int offset, int limit)
+        {
+            Offset = offset;
+            Limit = limit;
+        }
+
+        public PaginationParameters(int limit)
+            : this(0, limit)
+        {
+        }
+
+        /// <summary>
+        /// Returns a <see cref="PaginationParameters"/> of the next number of items defined by <paramref name="limit"/> after this.
+        /// </summary>
+        /// <param name="limit">The limit of the next pagination.</param>
+        public PaginationParameters TakeNext(int limit) => new PaginationParameters(Offset + Limit, limit);
+    }
+}

osu.Game/Online/API/Requests/Responses/APIPlayStyle.cs

@@ -1,22 +1,23 @@
 // 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;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Online.API.Requests.Responses
 {
     public enum APIPlayStyle
     {
-        [Description("Keyboard")]
+        [LocalisableDescription(typeof(CommonStrings), nameof(CommonStrings.DeviceKeyboard))]
         Keyboard,
 
-        [Description("Mouse")]
+        [LocalisableDescription(typeof(CommonStrings), nameof(CommonStrings.DeviceMouse))]
         Mouse,
 
-        [Description("Tablet")]
+        [LocalisableDescription(typeof(CommonStrings), nameof(CommonStrings.DeviceTablet))]
         Tablet,
 
-        [Description("Touch Screen")]
+        [LocalisableDescription(typeof(CommonStrings), nameof(CommonStrings.DeviceTouch))]
         Touch,
     }
 }

osu.Game/Online/Chat/ExternalLinkOpener.cs

@@ -17,7 +17,7 @@ namespace osu.Game.Online.Chat
         private GameHost host { get; set; }
 
         [Resolved(CanBeNull = true)]
-        private DialogOverlay dialogOverlay { get; set; }
+        private IDialogOverlay dialogOverlay { get; set; }
 
         private Bindable<bool> externalLinkWarning;
 

osu.Game/Online/Chat/MessageNotifier.cs

@@ -24,7 +24,7 @@ namespace osu.Game.Online.Chat
     public class MessageNotifier : Component
     {
         [Resolved]
-        private NotificationOverlay notifications { get; set; }
+        private INotificationOverlay notifications { get; set; }
 
         [Resolved]
         private ChatOverlay chatOverlay { get; set; }
@@ -170,7 +170,7 @@ namespace osu.Game.Online.Chat
             public override bool IsImportant => false;
 
             [BackgroundDependencyLoader]
-            private void load(OsuColour colours, ChatOverlay chatOverlay, NotificationOverlay notificationOverlay)
+            private void load(OsuColour colours, ChatOverlay chatOverlay, INotificationOverlay notificationOverlay)
             {
                 IconBackground.Colour = colours.PurpleDark;
 

osu.Game/Online/Chat/StandAloneChatDisplay.cs

@@ -12,6 +12,7 @@ using osu.Framework.Input.Events;
 using osu.Game.Graphics;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Overlays.Chat;
+using osu.Game.Resources.Localisation.Web;
 using osuTK.Graphics;
 
 namespace osu.Game.Online.Chat
@@ -63,7 +64,7 @@ namespace osu.Game.Online.Chat
                 {
                     RelativeSizeAxes = Axes.X,
                     Height = text_box_height,
-                    PlaceholderText = "type your message",
+                    PlaceholderText = ChatStrings.InputPlaceholder,
                     CornerRadius = corner_radius,
                     ReleaseFocusOnCommit = false,
                     HoldFocus = true,

osu.Game/Online/Leaderboards/LeaderboardScore.cs

@@ -30,6 +30,7 @@ using osu.Game.Users.Drawables;
 using osuTK;
 using osuTK.Graphics;
 using osu.Game.Online.API;
+using osu.Game.Resources.Localisation.Web;
 using osu.Game.Utils;
 
 namespace osu.Game.Online.Leaderboards
@@ -64,7 +65,7 @@ namespace osu.Game.Online.Leaderboards
         private List<ScoreComponentLabel> statisticsLabels;
 
         [Resolved(CanBeNull = true)]
-        private DialogOverlay dialogOverlay { get; set; }
+        private IDialogOverlay dialogOverlay { get; set; }
 
         [Resolved(CanBeNull = true)]
         private SongSelect songSelect { get; set; }
@@ -291,8 +292,8 @@ namespace osu.Game.Online.Leaderboards
 
         protected virtual IEnumerable<LeaderboardScoreStatistic> GetStatistics(ScoreInfo model) => new[]
         {
-            new LeaderboardScoreStatistic(FontAwesome.Solid.Link, "Max Combo", model.MaxCombo.ToString()),
+            new LeaderboardScoreStatistic(FontAwesome.Solid.Link, BeatmapsetsStrings.ShowScoreboardHeadersCombo, model.MaxCombo.ToString()),
-            new LeaderboardScoreStatistic(FontAwesome.Solid.Crosshairs, "Accuracy", model.DisplayAccuracy)
+            new LeaderboardScoreStatistic(FontAwesome.Solid.Crosshairs, BeatmapsetsStrings.ShowScoreboardHeadersAccuracy, model.DisplayAccuracy)
         };
 
         protected override bool OnHover(HoverEvent e)
@@ -403,9 +404,9 @@ namespace osu.Game.Online.Leaderboards
         {
             public IconUsage Icon;
             public LocalisableString Value;
-            public string Name;
+            public LocalisableString Name;
 
-            public LeaderboardScoreStatistic(IconUsage icon, string name, LocalisableString value)
+            public LeaderboardScoreStatistic(IconUsage icon, LocalisableString name, LocalisableString value)
             {
                 Icon = icon;
                 Name = name;
@@ -426,7 +427,7 @@ namespace osu.Game.Online.Leaderboards
                     items.Add(new OsuMenuItem("Export", MenuItemType.Standard, () => new LegacyScoreExporter(storage).Export(Score)));
 
                 if (!isOnlineScope)
-                    items.Add(new OsuMenuItem("Delete", MenuItemType.Destructive, () => dialogOverlay?.Push(new LocalScoreDeleteDialog(Score))));
+                    items.Add(new OsuMenuItem(CommonStrings.ButtonsDelete, MenuItemType.Destructive, () => dialogOverlay?.Push(new LocalScoreDeleteDialog(Score))));
 
                 return items.ToArray();
             }

osu.Game/Online/Multiplayer/MultiplayerClient.cs

@@ -67,7 +67,7 @@ namespace osu.Game.Online.Multiplayer
         /// <summary>
         /// Invoked when the multiplayer server requests the current beatmap to be loaded into play.
         /// </summary>
-        public event Action? LoadRequested;
+        public virtual event Action? LoadRequested;
 
         /// <summary>
         /// Invoked when the multiplayer server requests gameplay to be started.
@@ -114,12 +114,12 @@ namespace osu.Game.Online.Multiplayer
         /// <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);
+        public virtual 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
+        public virtual bool IsHost
         {
             get
             {

osu.Game/Online/Rooms/MatchType.cs

@@ -1,7 +1,8 @@
 // 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;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Online.Rooms
 {
@@ -11,10 +12,10 @@ namespace osu.Game.Online.Rooms
 
         Playlists,
 
-        [Description("Head to head")]
+        [LocalisableDescription(typeof(MatchesStrings), nameof(MatchesStrings.MatchTeamTypesHeadToHead))]
         HeadToHead,
 
-        [Description("Team VS")]
+        [LocalisableDescription(typeof(MatchesStrings), nameof(MatchesStrings.MatchTeamTypesTeamVs))]
         TeamVersus,
     }
 }

osu.Game/Online/Rooms/OnlinePlayBeatmapAvailabilityTracker.cs

@@ -25,7 +25,7 @@ namespace osu.Game.Online.Rooms
     /// This differs from a regular download tracking composite as this accounts for the
     /// databased beatmap set's checksum, to disallow from playing with an altered version of the beatmap.
     /// </summary>
-    public sealed class OnlinePlayBeatmapAvailabilityTracker : CompositeDrawable
+    public class OnlinePlayBeatmapAvailabilityTracker : CompositeDrawable
     {
         public readonly IBindable<PlaylistItem> SelectedItem = new Bindable<PlaylistItem>();
 
@@ -41,7 +41,7 @@ namespace osu.Game.Online.Rooms
         /// <summary>
         /// The availability state of the currently selected playlist item.
         /// </summary>
-        public IBindable<BeatmapAvailability> Availability => availability;
+        public virtual IBindable<BeatmapAvailability> Availability => availability;
 
         private readonly Bindable<BeatmapAvailability> availability = new Bindable<BeatmapAvailability>(BeatmapAvailability.NotDownloaded());
 

osu.Game/OsuGame.cs

@@ -63,7 +63,7 @@ namespace osu.Game
     /// The full osu! experience. Builds on top of <see cref="OsuGameBase"/> to add menus and binding logic
     /// for initial components that are generally retrieved via DI.
     /// </summary>
-    public class OsuGame : OsuGameBase, IKeyBindingHandler<GlobalAction>, ILocalUserPlayInfo
+    public class OsuGame : OsuGameBase, IKeyBindingHandler<GlobalAction>, ILocalUserPlayInfo, IPerformFromScreenRunner
     {
         /// <summary>
         /// The amount of global offset to apply when a left/right anchored overlay is displayed (ie. settings or notifications).
@@ -586,12 +586,6 @@ namespace osu.Game
 
         private PerformFromMenuRunner performFromMainMenuTask;
 
-        /// <summary>
-        /// Perform an action only after returning to a specific screen as indicated by <paramref name="validScreens"/>.
-        /// Eagerly tries to exit the current screen until it succeeds.
-        /// </summary>
-        /// <param name="action">The action to perform once we are in the correct state.</param>
-        /// <param name="validScreens">An optional collection of valid screen types. If any of these screens are already current we can perform the action immediately, else the first valid parent will be made current before performing the action. <see cref="MainMenu"/> is used if not specified.</param>
         public void PerformFromScreen(Action<IScreen> action, IEnumerable<Type> validScreens = null)
         {
             performFromMainMenuTask?.Cancel();
@@ -634,6 +628,14 @@ namespace osu.Game
 
             foreach (var language in Enum.GetValues(typeof(Language)).OfType<Language>())
             {
+#if DEBUG
+                if (language == Language.debug)
+                {
+                    Localisation.AddLanguage(Language.debug.ToString(), new DebugLocalisationStore());
+                    continue;
+                }
+#endif
+
                 string cultureCode = language.ToCultureCode();
 
                 try
@@ -778,7 +780,7 @@ namespace osu.Game
 
             loadComponentSingleFile(onScreenDisplay, Add, true);
 
-            loadComponentSingleFile(Notifications.With(d =>
+            loadComponentSingleFile<INotificationOverlay>(Notifications.With(d =>
             {
                 d.Anchor = Anchor.TopRight;
                 d.Origin = Anchor.TopRight;
@@ -825,7 +827,7 @@ namespace osu.Game
             }, rightFloatingOverlayContent.Add, true);
 
             loadComponentSingleFile(new AccountCreationOverlay(), topMostOverlayContent.Add, true);
-            loadComponentSingleFile(new DialogOverlay(), topMostOverlayContent.Add, true);
+            loadComponentSingleFile<IDialogOverlay>(new DialogOverlay(), topMostOverlayContent.Add, true);
 
             loadComponentSingleFile(CreateHighPerformanceSession(), Add);
 
@@ -982,12 +984,14 @@ namespace osu.Game
         /// <param name="component">The component to load.</param>
         /// <param name="loadCompleteAction">An action to invoke on load completion (generally to add the component to the hierarchy).</param>
         /// <param name="cache">Whether to cache the component as type <typeparamref name="T"/> into the game dependencies before any scheduling.</param>
-        private T loadComponentSingleFile<T>(T component, Action<T> loadCompleteAction, bool cache = false)
+        private T loadComponentSingleFile<T>(T component, Action<Drawable> loadCompleteAction, bool cache = false)
-            where T : Drawable
+            where T : class
         {
             if (cache)
                 dependencies.CacheAs(component);
 
+            var drawableComponent = component as Drawable ?? throw new ArgumentException($"Component must be a {nameof(Drawable)}", nameof(component));
+
             if (component is OsuFocusedOverlayContainer overlay)
                 focusedOverlays.Add(overlay);
 
@@ -1011,7 +1015,7 @@ namespace osu.Game
                         // Since this is running in a separate thread, it is possible for OsuGame to be disposed after LoadComponentAsync has been called
                         // throwing an exception. To avoid this, the call is scheduled on the update thread, which does not run if IsDisposed = true
                         Task task = null;
-                        var del = new ScheduledDelegate(() => task = LoadComponentAsync(component, loadCompleteAction));
+                        var del = new ScheduledDelegate(() => task = LoadComponentAsync(drawableComponent, loadCompleteAction));
                         Scheduler.Add(del);
 
                         // The delegate won't complete if OsuGame has been disposed in the meantime

osu.Game/Overlays/AccountCreation/AccountCreationScreen.cs

@@ -8,21 +8,21 @@ namespace osu.Game.Overlays.AccountCreation
 {
     public abstract class AccountCreationScreen : Screen
     {
-        public override void OnEntering(IScreen last)
+        public override void OnEntering(ScreenTransitionEvent e)
         {
-            base.OnEntering(last);
+            base.OnEntering(e);
             this.FadeOut().Delay(200).FadeIn(200);
         }
 
-        public override void OnResuming(IScreen last)
+        public override void OnResuming(ScreenTransitionEvent e)
         {
-            base.OnResuming(last);
+            base.OnResuming(e);
             this.FadeIn(200);
         }
 
-        public override void OnSuspending(IScreen next)
+        public override void OnSuspending(ScreenTransitionEvent e)
         {
-            base.OnSuspending(next);
+            base.OnSuspending(e);
             this.FadeOut(200);
         }
     }

osu.Game/Overlays/AccountCreation/ScreenEntry.cs

@@ -16,6 +16,7 @@ using osu.Game.Graphics.Sprites;
 using osu.Game.Graphics.UserInterface;
 using osu.Game.Online.API;
 using osu.Game.Overlays.Settings;
+using osu.Game.Resources.Localisation.Web;
 using osuTK;
 using osuTK.Graphics;
 
@@ -68,7 +69,7 @@ namespace osu.Game.Overlays.AccountCreation
                         },
                         usernameTextBox = new OsuTextBox
                         {
-                            PlaceholderText = "username",
+                            PlaceholderText = UsersStrings.LoginUsername,
                             RelativeSizeAxes = Axes.X,
                             TabbableContentContainer = this
                         },
@@ -146,9 +147,9 @@ namespace osu.Game.Overlays.AccountCreation
                 d.Colour = password.Length == 0 ? Color4.White : Interpolation.ValueAt(password.Length, Color4.OrangeRed, Color4.YellowGreen, 0, 8, Easing.In);
         }
 
-        public override void OnEntering(IScreen last)
+        public override void OnEntering(ScreenTransitionEvent e)
         {
-            base.OnEntering(last);
+            base.OnEntering(e);
             loadingLayer.Hide();
 
             if (host?.OnScreenKeyboardOverlapsGameWindow != true)

osu.Game/Overlays/AccountCreation/ScreenWarning.cs

@@ -31,7 +31,7 @@ namespace osu.Game.Overlays.AccountCreation
 
         private const string help_centre_url = "/help/wiki/Help_Centre#login";
 
-        public override void OnEntering(IScreen last)
+        public override void OnEntering(ScreenTransitionEvent e)
         {
             if (string.IsNullOrEmpty(api?.ProvidedUsername) || game?.UseDevelopmentServer == true)
             {
@@ -40,7 +40,7 @@ namespace osu.Game.Overlays.AccountCreation
                 return;
             }
 
-            base.OnEntering(last);
+            base.OnEntering(e);
         }
 
         [BackgroundDependencyLoader(true)]

osu.Game/Overlays/BeatmapSet/BeatmapAvailability.cs

@@ -8,6 +8,7 @@ using osu.Framework.Graphics.Shapes;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Resources.Localisation.Web;
 using osuTK.Graphics;
 
 namespace osu.Game.Overlays.BeatmapSet
@@ -69,14 +70,14 @@ namespace osu.Game.Overlays.BeatmapSet
         {
             textContainer.Clear();
             textContainer.AddParagraph(downloadDisabled
-                ? "This beatmap is currently not available for download."
+                ? BeatmapsetsStrings.AvailabilityDisabled
-                : "Portions of this beatmap have been removed at the request of the creator or a third-party rights holder.", t => t.Colour = Color4.Orange);
+                : BeatmapsetsStrings.AvailabilityPartsRemoved, t => t.Colour = Color4.Orange);
 
             if (hasExternalLink)
             {
                 textContainer.NewParagraph();
                 textContainer.NewParagraph();
-                textContainer.AddLink("Check here for more information.", BeatmapSet.Availability.ExternalLink, creationParameters: t => t.Font = OsuFont.GetFont(size: 10));
+                textContainer.AddLink(BeatmapsetsStrings.AvailabilityMoreInfo, BeatmapSet.Availability.ExternalLink, creationParameters: t => t.Font = OsuFont.GetFont(size: 10));
             }
         }
     }

osu.Game/Overlays/BeatmapSet/Buttons/FavouriteButton.cs

@@ -41,7 +41,7 @@ namespace osu.Game.Overlays.BeatmapSet.Buttons
         }
 
         [BackgroundDependencyLoader(true)]
-        private void load(IAPIProvider api, NotificationOverlay notifications)
+        private void load(IAPIProvider api, INotificationOverlay notifications)
         {
             SpriteIcon icon;
 

osu.Game/Overlays/BeatmapSet/Scores/NotSupporterPlaceholder.cs

@@ -7,6 +7,7 @@ using osu.Game.Graphics.Sprites;
 using osuTK;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.BeatmapSet.Scores
 {
@@ -28,7 +29,7 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
                     {
                         Anchor = Anchor.TopCentre,
                         Origin = Anchor.TopCentre,
-                        Text = @"You need to be an osu!supporter to access the friend and country rankings!",
+                        Text = BeatmapsetsStrings.ShowScoreboardSupporterOnly,
                         Font = OsuFont.GetFont(size: 14, weight: FontWeight.Bold),
                     },
                     text = new LinkFlowContainer(t => t.Font = t.Font.With(size: 11))

osu.Game/Overlays/Chat/ChannelList/ChannelList.cs

@@ -0,0 +1,135 @@
+// 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 osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.Sprites;
+using osu.Game.Online.Chat;
+
+namespace osu.Game.Overlays.Chat.ChannelList
+{
+    public class ChannelList : Container
+    {
+        public Action<Channel>? OnRequestSelect;
+        public Action<Channel>? OnRequestLeave;
+
+        public readonly BindableBool SelectorActive = new BindableBool();
+
+        private readonly Dictionary<Channel, ChannelListItem> channelMap = new Dictionary<Channel, ChannelListItem>();
+
+        private ChannelListItemFlow publicChannelFlow = null!;
+        private ChannelListItemFlow privateChannelFlow = null!;
+
+        [BackgroundDependencyLoader]
+        private void load(OverlayColourProvider colourProvider)
+        {
+            Children = new Drawable[]
+            {
+                new Box
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Colour = colourProvider.Background6,
+                },
+                new OsuScrollContainer
+                {
+                    Padding = new MarginPadding { Vertical = 7 },
+                    RelativeSizeAxes = Axes.Both,
+                    ScrollbarAnchor = Anchor.TopRight,
+                    ScrollDistance = 35f,
+                    Child = new FillFlowContainer
+                    {
+                        Direction = FillDirection.Vertical,
+                        RelativeSizeAxes = Axes.X,
+                        AutoSizeAxes = Axes.Y,
+                        Children = new Drawable[]
+                        {
+                            publicChannelFlow = new ChannelListItemFlow("CHANNELS"),
+                            new ChannelListSelector
+                            {
+                                Margin = new MarginPadding { Bottom = 10 },
+                                SelectorActive = { BindTarget = SelectorActive },
+                            },
+                            privateChannelFlow = new ChannelListItemFlow("DIRECT MESSAGES"),
+                        },
+                    },
+                },
+            };
+        }
+
+        public void AddChannel(Channel channel)
+        {
+            if (channelMap.ContainsKey(channel))
+                return;
+
+            ChannelListItem item = new ChannelListItem(channel);
+            item.OnRequestSelect += chan => OnRequestSelect?.Invoke(chan);
+            item.OnRequestLeave += chan => OnRequestLeave?.Invoke(chan);
+            item.SelectorActive.BindTarget = SelectorActive;
+
+            ChannelListItemFlow flow = getFlowForChannel(channel);
+            channelMap.Add(channel, item);
+            flow.Add(item);
+        }
+
+        public void RemoveChannel(Channel channel)
+        {
+            if (!channelMap.ContainsKey(channel))
+                return;
+
+            ChannelListItem item = channelMap[channel];
+            ChannelListItemFlow flow = getFlowForChannel(channel);
+
+            channelMap.Remove(channel);
+            flow.Remove(item);
+        }
+
+        public ChannelListItem GetItem(Channel channel)
+        {
+            if (!channelMap.ContainsKey(channel))
+                throw new ArgumentOutOfRangeException();
+
+            return channelMap[channel];
+        }
+
+        private ChannelListItemFlow getFlowForChannel(Channel channel)
+        {
+            switch (channel.Type)
+            {
+                case ChannelType.Public:
+                    return publicChannelFlow;
+
+                case ChannelType.PM:
+                    return privateChannelFlow;
+
+                default:
+                    throw new ArgumentOutOfRangeException();
+            }
+        }
+
+        private class ChannelListItemFlow : FillFlowContainer
+        {
+            public ChannelListItemFlow(string label)
+            {
+                Direction = FillDirection.Vertical;
+                RelativeSizeAxes = Axes.X;
+                AutoSizeAxes = Axes.Y;
+
+                Add(new OsuSpriteText
+                {
+                    Text = label,
+                    Margin = new MarginPadding { Left = 18, Bottom = 5 },
+                    Font = OsuFont.Torus.With(size: 12, weight: FontWeight.SemiBold),
+                });
+            }
+        }
+    }
+}

osu.Game/Overlays/Chat/ChannelList/ChannelListItem.cs

@@ -29,12 +29,14 @@ namespace osu.Game.Overlays.Chat.ChannelList
 
         public readonly BindableBool Unread = new BindableBool();
 
+        public readonly BindableBool SelectorActive = new BindableBool();
+
         private readonly Channel channel;
 
-        private Box? hoverBox;
+        private Box hoverBox = null!;
-        private Box? selectBox;
+        private Box selectBox = null!;
-        private OsuSpriteText? text;
+        private OsuSpriteText text = null!;
-        private ChannelListItemCloseButton? close;
+        private ChannelListItemCloseButton close = null!;
 
         [Resolved]
         private Bindable<Channel> selectedChannel { get; set; } = null!;
@@ -124,31 +126,26 @@ namespace osu.Game.Overlays.Chat.ChannelList
         {
             base.LoadComplete();
 
-            selectedChannel.BindValueChanged(change =>
+            selectedChannel.BindValueChanged(_ => updateSelectState(), true);
-            {
+            SelectorActive.BindValueChanged(_ => updateSelectState(), true);
-                if (change.NewValue == channel)
-                    selectBox?.FadeIn(300, Easing.OutQuint);
-                else
-                    selectBox?.FadeOut(200, Easing.OutQuint);
-            }, true);
 
             Unread.BindValueChanged(change =>
             {
-                text!.FadeColour(change.NewValue ? colourProvider.Content1 : colourProvider.Light3, 300, Easing.OutQuint);
+                text.FadeColour(change.NewValue ? colourProvider.Content1 : colourProvider.Light3, 300, Easing.OutQuint);
             }, true);
         }
 
         protected override bool OnHover(HoverEvent e)
         {
-            hoverBox?.FadeIn(300, Easing.OutQuint);
+            hoverBox.FadeIn(300, Easing.OutQuint);
-            close?.FadeIn(300, Easing.OutQuint);
+            close.FadeIn(300, Easing.OutQuint);
             return base.OnHover(e);
         }
 
         protected override void OnHoverLost(HoverLostEvent e)
         {
-            hoverBox?.FadeOut(200, Easing.OutQuint);
+            hoverBox.FadeOut(200, Easing.OutQuint);
-            close?.FadeOut(200, Easing.OutQuint);
+            close.FadeOut(200, Easing.OutQuint);
             base.OnHoverLost(e);
         }
 
@@ -167,5 +164,13 @@ namespace osu.Game.Overlays.Chat.ChannelList
                 Masking = true,
             };
         }
+
+        private void updateSelectState()
+        {
+            if (selectedChannel.Value == channel && !SelectorActive.Value)
+                selectBox.FadeIn(300, Easing.OutQuint);
+            else
+                selectBox.FadeOut(200, Easing.OutQuint);
+        }
     }
 }

osu.Game/Overlays/Chat/ChannelList/ChannelListSelector.cs

@@ -0,0 +1,91 @@
+// 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 osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Shapes;
+using osu.Framework.Input.Events;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.Sprites;
+
+namespace osu.Game.Overlays.Chat.ChannelList
+{
+    public class ChannelListSelector : OsuClickableContainer
+    {
+        public readonly BindableBool SelectorActive = new BindableBool();
+
+        private Box hoverBox = null!;
+        private Box selectBox = null!;
+
+        [BackgroundDependencyLoader]
+        private void load(OverlayColourProvider colourProvider)
+        {
+            Height = 30;
+            RelativeSizeAxes = Axes.X;
+
+            Children = new Drawable[]
+            {
+                hoverBox = new Box
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Colour = colourProvider.Background3,
+                    Alpha = 0f,
+                },
+                selectBox = new Box
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Colour = colourProvider.Background4,
+                    Alpha = 0f,
+                },
+                new Container
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Padding = new MarginPadding { Left = 18, Right = 10 },
+                    Child = new OsuSpriteText
+                    {
+                        Anchor = Anchor.CentreLeft,
+                        Origin = Anchor.CentreLeft,
+                        Text = "Add More Channels",
+                        Font = OsuFont.Torus.With(size: 17, weight: FontWeight.SemiBold),
+                        Colour = colourProvider.Light3,
+                        Margin = new MarginPadding { Bottom = 2 },
+                        RelativeSizeAxes = Axes.X,
+                        Truncate = true,
+                    },
+                },
+            };
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            SelectorActive.BindValueChanged(selector =>
+            {
+                if (selector.NewValue)
+                    selectBox.FadeIn(300, Easing.OutQuint);
+                else
+                    selectBox.FadeOut(200, Easing.OutQuint);
+            }, true);
+
+            Action = () => SelectorActive.Value = true;
+        }
+
+        protected override bool OnHover(HoverEvent e)
+        {
+            hoverBox.FadeIn(300, Easing.OutQuint);
+            return base.OnHover(e);
+        }
+
+        protected override void OnHoverLost(HoverLostEvent e)
+        {
+            hoverBox.FadeOut(200, Easing.OutQuint);
+            base.OnHoverLost(e);
+        }
+    }
+}

osu.Game/Overlays/ChatOverlay.cs

@@ -160,7 +160,7 @@ namespace osu.Game.Overlays
                                                 {
                                                     RelativeSizeAxes = Axes.Both,
                                                     Height = 1,
-                                                    PlaceholderText = "type your message",
+                                                    PlaceholderText = Resources.Localisation.Web.ChatStrings.InputPlaceholder,
                                                     ReleaseFocusOnCommit = false,
                                                     HoldFocus = true,
                                                 }

osu.Game/Overlays/Comments/Buttons/LoadRepliesButton.cs

@@ -3,6 +3,7 @@
 
 using osu.Framework.Graphics;
 using osu.Game.Graphics.UserInterface;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Comments.Buttons
 {
@@ -25,7 +26,7 @@ namespace osu.Game.Overlays.Comments.Buttons
         {
             public ButtonContent()
             {
-                Text = "load replies";
+                Text = CommentsStrings.LoadReplies;
             }
         }
     }

osu.Game/Overlays/Comments/Buttons/ShowMoreRepliesButton.cs

@@ -9,6 +9,7 @@ using osu.Game.Graphics.Sprites;
 using System.Collections.Generic;
 using osuTK;
 using osu.Framework.Allocation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Comments.Buttons
 {
@@ -38,7 +39,7 @@ namespace osu.Game.Overlays.Comments.Buttons
             {
                 AlwaysPresent = true,
                 Font = OsuFont.GetFont(size: 12, weight: FontWeight.SemiBold),
-                Text = "show more"
+                Text = CommonStrings.ButtonsShowMore
             }
         };
 

osu.Game/Overlays/Comments/CancellableCommentEditor.cs

@@ -10,6 +10,7 @@ using osu.Framework.Graphics.Shapes;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Comments
 {
@@ -54,7 +55,7 @@ namespace osu.Game.Overlays.Comments
                             Origin = Anchor.Centre,
                             Font = OsuFont.GetFont(size: 12, weight: FontWeight.Bold),
                             Margin = new MarginPadding { Horizontal = 20 },
-                            Text = @"Cancel"
+                            Text = CommonStrings.ButtonsCancel
                         }
                     }
                 };

osu.Game/Overlays/Comments/CommentsContainer.cs

@@ -16,6 +16,7 @@ using osu.Framework.Threading;
 using System.Collections.Generic;
 using JetBrains.Annotations;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Resources.Localisation.Web;
 using APIUser = osu.Game.Online.API.Requests.Responses.APIUser;
 
 namespace osu.Game.Overlays.Comments
@@ -328,7 +329,7 @@ namespace osu.Game.Overlays.Comments
                         Anchor = Anchor.CentreLeft,
                         Origin = Anchor.CentreLeft,
                         Margin = new MarginPadding { Left = 50 },
-                        Text = @"No comments yet."
+                        Text = CommentsStrings.Empty
                     }
                 });
             }

osu.Game/Overlays/Comments/CommentsHeader.cs

@@ -12,7 +12,9 @@ using osu.Game.Graphics;
 using osu.Framework.Graphics.Sprites;
 using osuTK;
 using osu.Framework.Input.Events;
+using osu.Framework.Localisation;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Comments
 {
@@ -91,7 +93,7 @@ namespace osu.Game.Overlays.Comments
                             Anchor = Anchor.CentreLeft,
                             Origin = Anchor.CentreLeft,
                             Font = OsuFont.GetFont(size: 12, weight: FontWeight.SemiBold),
-                            Text = @"Show deleted"
+                            Text = CommonStrings.ButtonsShowDeleted
                         }
                     },
                 });
@@ -126,9 +128,13 @@ namespace osu.Game.Overlays.Comments
 
     public enum CommentsSortCriteria
     {
-        [System.ComponentModel.Description(@"Recent")]
+        [LocalisableDescription(typeof(SortStrings), nameof(SortStrings.New))]
         New,
+
+        [LocalisableDescription(typeof(SortStrings), nameof(SortStrings.Old))]
         Old,
+
+        [LocalisableDescription(typeof(SortStrings), nameof(SortStrings.Top))]
         Top
     }
 }

osu.Game/Overlays/Comments/CommentsShowMoreButton.cs

@@ -2,7 +2,10 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Bindables;
+using osu.Framework.Extensions.LocalisationExtensions;
+using osu.Framework.Localisation;
 using osu.Game.Graphics.UserInterface;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Comments
 {
@@ -18,7 +21,8 @@ namespace osu.Game.Overlays.Comments
 
         private void onCurrentChanged(ValueChangedEvent<int> count)
         {
-            Text = $@"Show More ({count.NewValue})".ToUpper();
+            Text = new TranslatableString(@"_", "{0} ({1})",
+                CommonStrings.ButtonsShowMore.ToUpper(), count.NewValue);
         }
     }
 }

osu.Game/Overlays/Comments/DrawableComment.cs

@@ -150,7 +150,7 @@ namespace osu.Game.Overlays.Comments
                                                         {
                                                             Alpha = Comment.IsDeleted ? 1 : 0,
                                                             Font = OsuFont.GetFont(size: 14, weight: FontWeight.Bold),
-                                                            Text = "deleted"
+                                                            Text = CommentsStrings.Deleted
                                                         }
                                                     }
                                                 },

osu.Game/Overlays/Comments/TotalCommentsCounter.cs

@@ -9,6 +9,7 @@ using osuTK;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Comments
 {
@@ -39,7 +40,7 @@ namespace osu.Game.Overlays.Comments
                         Origin = Anchor.CentreLeft,
                         Font = OsuFont.GetFont(size: 20, italics: true),
                         Colour = colourProvider.Light1,
-                        Text = @"Comments"
+                        Text = CommentsStrings.Title
                     },
                     new CircularContainer
                     {

osu.Game/Overlays/Dashboard/CurrentlyPlayingDisplay.cs

@@ -14,6 +14,7 @@ using osu.Game.Database;
 using osu.Game.Online.API;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Online.Spectator;
+using osu.Game.Screens;
 using osu.Game.Screens.OnlinePlay.Match.Components;
 using osu.Game.Screens.Play;
 using osu.Game.Users;
@@ -106,7 +107,7 @@ namespace osu.Game.Overlays.Dashboard
             public readonly APIUser User;
 
             [Resolved(canBeNull: true)]
-            private OsuGame game { get; set; }
+            private IPerformFromScreenRunner performer { get; set; }
 
             public PlayingUserPanel(APIUser user)
             {
@@ -137,10 +138,10 @@ namespace osu.Game.Overlays.Dashboard
                             new PurpleTriangleButton
                             {
                                 RelativeSizeAxes = Axes.X,
-                                Text = "Watch",
+                                Text = "Spectate",
                                 Anchor = Anchor.TopCentre,
                                 Origin = Anchor.TopCentre,
-                                Action = () => game?.PerformFromScreen(s => s.Push(new SoloSpectator(User))),
+                                Action = () => performer?.PerformFromScreen(s => s.Push(new SoloSpectator(User))),
                                 Enabled = { Value = User.Id != api.LocalUser.Value.Id }
                             }
                         }

osu.Game/Overlays/Dashboard/Home/DrawableBeatmapList.cs

@@ -6,6 +6,7 @@ using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
+using osu.Framework.Localisation;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Online.API.Requests.Responses;
@@ -49,7 +50,7 @@ namespace osu.Game.Overlays.Dashboard.Home
             flow.AddRange(beatmapSets.Select(CreateBeatmapPanel));
         }
 
-        protected abstract string Title { get; }
+        protected abstract LocalisableString Title { get; }
 
         protected abstract DashboardBeatmapPanel CreateBeatmapPanel(APIBeatmapSet beatmapSet);
     }

osu.Game/Overlays/Dashboard/Home/DrawableNewBeatmapList.cs

@@ -2,7 +2,9 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using osu.Framework.Localisation;
 using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Dashboard.Home
 {
@@ -15,6 +17,6 @@ namespace osu.Game.Overlays.Dashboard.Home
 
         protected override DashboardBeatmapPanel CreateBeatmapPanel(APIBeatmapSet beatmapSet) => new DashboardNewBeatmapPanel(beatmapSet);
 
-        protected override string Title => "New Ranked Beatmaps";
+        protected override LocalisableString Title => HomeStrings.UserBeatmapsNew;
     }
 }

osu.Game/Overlays/Dashboard/Home/DrawablePopularBeatmapList.cs

@@ -2,7 +2,9 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System.Collections.Generic;
+using osu.Framework.Localisation;
 using osu.Game.Online.API.Requests.Responses;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Dashboard.Home
 {
@@ -15,6 +17,6 @@ namespace osu.Game.Overlays.Dashboard.Home
 
         protected override DashboardBeatmapPanel CreateBeatmapPanel(APIBeatmapSet beatmapSet) => new DashboardPopularBeatmapPanel(beatmapSet);
 
-        protected override string Title => "Popular Beatmaps";
+        protected override LocalisableString Title => HomeStrings.UserBeatmapsPopular;
     }
 }

osu.Game/Overlays/Dashboard/Home/News/ShowMoreNewsPanel.cs

@@ -6,6 +6,7 @@ using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Resources.Localisation.Web;
 using osuTK.Graphics;
 
 namespace osu.Game.Overlays.Dashboard.Home.News
@@ -35,7 +36,7 @@ namespace osu.Game.Overlays.Dashboard.Home.News
                     Anchor = Anchor.Centre,
                     Origin = Anchor.Centre,
                     Margin = new MarginPadding { Vertical = 20 },
-                    Text = "see more"
+                    Text = CommonStrings.ButtonsSeeMore
                 }
             };
 

osu.Game/Overlays/Dialog/ConfirmDialog.cs

@@ -3,6 +3,7 @@
 
 using System;
 using osu.Framework.Graphics.Sprites;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.Dialog
 {
@@ -33,7 +34,7 @@ namespace osu.Game.Overlays.Dialog
                 },
                 new PopupDialogCancelButton
                 {
-                    Text = Localisation.CommonStrings.Cancel,
+                    Text = CommonStrings.ButtonsCancel,
                     Action = onCancel
                 },
             };

osu.Game/Overlays/Dialog/PopupDialog.cs

@@ -88,9 +88,13 @@ namespace osu.Game.Overlays.Dialog
                         if (actionInvoked) return;
 
                         actionInvoked = true;
-                        action?.Invoke();
 
+                        // Hide the dialog before running the action.
+                        // This is important as the code which is performed may check for a dialog being present (ie. `OsuGame.PerformFromScreen`)
+                        // and we don't want it to see the already dismissed dialog.
                         Hide();
+
+                        action?.Invoke();
                     };
                 }
             }
@@ -212,7 +216,7 @@ namespace osu.Game.Overlays.Dialog
             };
 
             // It's important we start in a visible state so our state fires on hide, even before load.
-            // This is used by the DialogOverlay to know when the dialog was dismissed.
+            // This is used by the dialog overlay to know when the dialog was dismissed.
             Show();
         }
 

osu.Game/Overlays/DialogOverlay.cs

@@ -14,7 +14,7 @@ using osu.Game.Audio.Effects;
 
 namespace osu.Game.Overlays
 {
-    public class DialogOverlay : OsuFocusedOverlayContainer
+    public class DialogOverlay : OsuFocusedOverlayContainer, IDialogOverlay
     {
         private readonly Container dialogContainer;
 

osu.Game/Overlays/IDialogOverlay.cs

@@ -0,0 +1,32 @@
+// 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 osu.Framework.Allocation;
+using osu.Game.Overlays.Dialog;
+
+namespace osu.Game.Overlays
+{
+    /// <summary>
+    /// A global overlay that can show popup dialogs.
+    /// </summary>
+    [Cached(typeof(IDialogOverlay))]
+    public interface IDialogOverlay
+    {
+        /// <summary>
+        /// Push a new dialog for display.
+        /// </summary>
+        /// <remarks>
+        /// This will immediate dismiss any already displayed dialog (cancelling the action).
+        /// If the dialog instance provided is already displayed, it will be a noop.
+        /// </remarks>
+        /// <param name="dialog">The dialog to be presented.</param>
+        void Push(PopupDialog dialog);
+
+        /// <summary>
+        /// The currently displayed dialog, if any.
+        /// </summary>
+        PopupDialog? CurrentDialog { get; }
+    }
+}