Merge branch 'master' into skin-editor-closest-anchor

osu.Game/Beatmaps/ControlPoints/ControlPointInfo.cs

@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using JetBrains.Annotations;
 using Newtonsoft.Json;
 using osu.Framework.Bindables;
 using osu.Framework.Lists;
@@ -66,6 +67,7 @@ namespace osu.Game.Beatmaps.ControlPoints
         /// </summary>
         /// <param name="time">The time to find the difficulty control point at.</param>
         /// <returns>The difficulty control point.</returns>
+        [NotNull]
         public DifficultyControlPoint DifficultyPointAt(double time) => binarySearchWithFallback(DifficultyPoints, time, DifficultyControlPoint.DEFAULT);
 
         /// <summary>
@@ -73,6 +75,7 @@ namespace osu.Game.Beatmaps.ControlPoints
         /// </summary>
         /// <param name="time">The time to find the effect control point at.</param>
         /// <returns>The effect control point.</returns>
+        [NotNull]
         public EffectControlPoint EffectPointAt(double time) => binarySearchWithFallback(EffectPoints, time, EffectControlPoint.DEFAULT);
 
         /// <summary>
@@ -80,6 +83,7 @@ namespace osu.Game.Beatmaps.ControlPoints
         /// </summary>
         /// <param name="time">The time to find the sound control point at.</param>
         /// <returns>The sound control point.</returns>
+        [NotNull]
         public SampleControlPoint SamplePointAt(double time) => binarySearchWithFallback(SamplePoints, time, SamplePoints.Count > 0 ? SamplePoints[0] : SampleControlPoint.DEFAULT);
 
         /// <summary>
@@ -87,6 +91,7 @@ namespace osu.Game.Beatmaps.ControlPoints
         /// </summary>
         /// <param name="time">The time to find the timing control point at.</param>
         /// <returns>The timing control point.</returns>
+        [NotNull]
         public TimingControlPoint TimingPointAt(double time) => binarySearchWithFallback(TimingPoints, time, TimingPoints.Count > 0 ? TimingPoints[0] : TimingControlPoint.DEFAULT);
 
         /// <summary>

osu.Game/Beatmaps/DifficultyRecommender.cs

@@ -101,10 +101,20 @@ namespace osu.Game.Beatmaps
         /// Rulesets ordered descending by their respective recommended difficulties.
         /// The currently selected ruleset will always be first.
         /// </returns>
-        private IEnumerable<RulesetInfo> orderedRulesets =>
-            recommendedDifficultyMapping
-                .OrderByDescending(pair => pair.Value).Select(pair => pair.Key).Where(r => !r.Equals(ruleset.Value))
-                .Prepend(ruleset.Value);
+        private IEnumerable<RulesetInfo> orderedRulesets
+        {
+            get
+            {
+                if (LoadState < LoadState.Ready || ruleset.Value == null)
+                    return Enumerable.Empty<RulesetInfo>();
+
+                return recommendedDifficultyMapping
+                       .OrderByDescending(pair => pair.Value)
+                       .Select(pair => pair.Key)
+                       .Where(r => !r.Equals(ruleset.Value))
+                       .Prepend(ruleset.Value);
+            }
+        }
 
         private void onlineStateChanged(ValueChangedEvent<APIState> state) => Schedule(() =>
         {

osu.Game/Beatmaps/MetadataUtils.cs

@@ -0,0 +1,47 @@
+// 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.Linq;
+using System.Text;
+
+namespace osu.Game.Beatmaps
+{
+    /// <summary>
+    /// Groups utility methods used to handle beatmap metadata.
+    /// </summary>
+    public static class MetadataUtils
+    {
+        /// <summary>
+        /// Returns <see langword="true"/> if the character <paramref name="c"/> can be used in <see cref="BeatmapMetadata.Artist"/> and <see cref="BeatmapMetadata.Title"/> fields.
+        /// Characters not matched by this method can be placed in <see cref="BeatmapMetadata.ArtistUnicode"/> and <see cref="BeatmapMetadata.TitleUnicode"/>.
+        /// </summary>
+        public static bool IsRomanised(char c) => c <= 0xFF;
+
+        /// <summary>
+        /// Returns <see langword="true"/> if the string <paramref name="str"/> can be used in <see cref="BeatmapMetadata.Artist"/> and <see cref="BeatmapMetadata.Title"/> fields.
+        /// Strings not matched by this method can be placed in <see cref="BeatmapMetadata.ArtistUnicode"/> and <see cref="BeatmapMetadata.TitleUnicode"/>.
+        /// </summary>
+        public static bool IsRomanised(string? str) => string.IsNullOrEmpty(str) || str.All(IsRomanised);
+
+        /// <summary>
+        /// Returns a copy of <paramref name="str"/> with all characters that do not match <see cref="IsRomanised(char)"/> removed.
+        /// </summary>
+        public static string StripNonRomanisedCharacters(string? str)
+        {
+            if (string.IsNullOrEmpty(str))
+                return string.Empty;
+
+            var stringBuilder = new StringBuilder(str.Length);
+
+            foreach (var c in str)
+            {
+                if (IsRomanised(c))
+                    stringBuilder.Append(c);
+            }
+
+            return stringBuilder.ToString().Trim();
+        }
+    }
+}

osu.Game/Beatmaps/WorkingBeatmap.cs

@@ -325,6 +325,7 @@ namespace osu.Game.Beatmaps
         public ISkin Skin => skin.Value;
 
         protected abstract ISkin GetSkin();
+
         private readonly RecyclableLazy<ISkin> skin;
 
         public abstract Stream GetStream(string storagePath);

osu.Game/Collections/CollectionManager.cs

@@ -264,14 +264,18 @@ namespace osu.Game.Collections
                     using (var sw = new SerializationWriter(storage.GetStream(database_name, FileAccess.Write)))
                     {
                         sw.Write(database_version);
-                        sw.Write(Collections.Count);
 
-                        foreach (var c in Collections)
+                        var collectionsCopy = Collections.ToArray();
+                        sw.Write(collectionsCopy.Length);
+
+                        foreach (var c in collectionsCopy)
                         {
                             sw.Write(c.Name.Value);
-                            sw.Write(c.Beatmaps.Count);
 
-                            foreach (var b in c.Beatmaps)
+                            var beatmapsCopy = c.Beatmaps.ToArray();
+                            sw.Write(beatmapsCopy.Length);
+
+                            foreach (var b in beatmapsCopy)
                                 sw.Write(b.MD5Hash);
                         }
                     }

osu.Game/Configuration/OsuConfigManager.cs

@@ -61,6 +61,9 @@ namespace osu.Game.Configuration
 
             SetDefault(OsuSetting.ShowOnlineExplicitContent, false);
 
+            SetDefault(OsuSetting.NotifyOnUsernameMentioned, true);
+            SetDefault(OsuSetting.NotifyOnPrivateMessage, true);
+
             // Audio
             SetDefault(OsuSetting.VolumeInactive, 0.25, 0, 1, 0.01);
 
@@ -259,6 +262,8 @@ namespace osu.Game.Configuration
         ScalingSizeY,
         UIScale,
         IntroSequence,
+        NotifyOnUsernameMentioned,
+        NotifyOnPrivateMessage,
         UIHoldActivationDelay,
         HitLighting,
         MenuBackgroundSource,

osu.Game/Configuration/RankingType.cs

@@ -1,20 +0,0 @@
-// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
-// See the LICENCE file in the repository root for full licence text.
-
-using System.ComponentModel;
-
-namespace osu.Game.Configuration
-{
-    public enum RankingType
-    {
-        Local,
-
-        [Description("Global")]
-        Top,
-
-        [Description("Selected Mods")]
-        SelectedMod,
-        Friends,
-        Country
-    }
-}

osu.Game/Extensions/LanguageExtensions.cs

@@ -0,0 +1,33 @@
+// 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.Globalization;
+using osu.Game.Localisation;
+
+namespace osu.Game.Extensions
+{
+    /// <summary>
+    /// Conversion utilities for the <see cref="Language"/> enum.
+    /// </summary>
+    public static class LanguageExtensions
+    {
+        /// <summary>
+        /// Returns the culture code of the <see cref="CultureInfo"/> that corresponds to the supplied <paramref name="language"/>.
+        /// </summary>
+        /// <remarks>
+        /// This is required as enum member names are not allowed to contain hyphens.
+        /// </remarks>
+        public static string ToCultureCode(this Language language)
+            => language.ToString().Replace("_", "-");
+
+        /// <summary>
+        /// Attempts to parse the supplied <paramref name="cultureCode"/> to a <see cref="Language"/> value.
+        /// </summary>
+        /// <param name="cultureCode">The code of the culture to parse.</param>
+        /// <param name="language">The parsed <see cref="Language"/>. Valid only if the return value of the method is <see langword="true" />.</param>
+        /// <returns>Whether the parsing succeeded.</returns>
+        public static bool TryParseCultureCode(string cultureCode, out Language language)
+            => Enum.TryParse(cultureCode.Replace("-", "_"), out language);
+    }
+}

osu.Game/Graphics/Backgrounds/Background.cs

@@ -1,6 +1,7 @@
 // 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 osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -14,7 +15,7 @@ namespace osu.Game.Graphics.Backgrounds
     /// <summary>
     /// A background which offers blurring via a <see cref="BufferedContainer"/> on demand.
     /// </summary>
-    public class Background : CompositeDrawable
+    public class Background : CompositeDrawable, IEquatable<Background>
     {
         private const float blur_scale = 0.5f;
 
@@ -71,5 +72,14 @@ namespace osu.Game.Graphics.Backgrounds
 
             bufferedContainer?.BlurTo(newBlurSigma * blur_scale, duration, easing);
         }
+
+        public virtual bool Equals(Background other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return other.GetType() == GetType()
+                   && other.textureName == textureName;
+        }
     }
 }

osu.Game/Graphics/Backgrounds/BeatmapBackground.cs

@@ -24,5 +24,14 @@ namespace osu.Game.Graphics.Backgrounds
         {
             Sprite.Texture = Beatmap?.Background ?? textures.Get(fallbackTextureName);
         }
+
+        public override bool Equals(Background other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return other.GetType() == GetType()
+                   && ((BeatmapBackground)other).Beatmap == Beatmap;
+        }
     }
 }

osu.Game/Graphics/Backgrounds/SeasonalBackgroundLoader.cs

@@ -99,5 +99,14 @@ namespace osu.Game.Graphics.Backgrounds
             // ensure we're not loading in without a transition.
             this.FadeInFromZero(200, Easing.InOutSine);
         }
+
+        public override bool Equals(Background other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return other.GetType() == GetType()
+                   && ((SeasonalBackground)other).url == url;
+        }
     }
 }

osu.Game/Graphics/Backgrounds/SkinBackground.cs

@@ -0,0 +1,34 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using osu.Framework.Allocation;
+using osu.Game.Skinning;
+
+namespace osu.Game.Graphics.Backgrounds
+{
+    internal class SkinBackground : Background
+    {
+        private readonly Skin skin;
+
+        public SkinBackground(Skin skin, string fallbackTextureName)
+            : base(fallbackTextureName)
+        {
+            this.skin = skin;
+        }
+
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            Sprite.Texture = skin.GetTexture("menu-background") ?? Sprite.Texture;
+        }
+
+        public override bool Equals(Background other)
+        {
+            if (ReferenceEquals(null, other)) return false;
+            if (ReferenceEquals(this, other)) return true;
+
+            return other.GetType() == GetType()
+                   && ((SkinBackground)other).skin.SkinInfo.Equals(skin.SkinInfo);
+        }
+    }
+}

osu.Game/Graphics/Backgrounds/Triangles.cs

@@ -57,12 +57,6 @@ namespace osu.Game.Graphics.Backgrounds
             }
         }
 
-        /// <summary>
-        /// Whether we want to expire triangles as they exit our draw area completely.
-        /// </summary>
-        [Obsolete("Unused.")] // Can be removed 20210518
-        protected virtual bool ExpireOffScreenTriangles => true;
-
         /// <summary>
         /// Whether we should create new triangles as others expire.
         /// </summary>

osu.Game/Graphics/Containers/Markdown/OsuMarkdownContainer.cs

@@ -30,9 +30,12 @@ namespace osu.Game.Graphics.Containers.Markdown
                     break;
 
                 case ListItemBlock listItemBlock:
-                    var isOrdered = ((ListBlock)listItemBlock.Parent).IsOrdered;
-                    var childContainer = CreateListItem(listItemBlock, level, isOrdered);
+                    bool isOrdered = ((ListBlock)listItemBlock.Parent)?.IsOrdered == true;
+
+                    OsuMarkdownListItem childContainer = CreateListItem(listItemBlock, level, isOrdered);
+
                     container.Add(childContainer);
+
                     foreach (var single in listItemBlock)
                         base.AddMarkdownComponent(single, childContainer.Content, level);
                     break;

osu.Game/Graphics/Containers/Markdown/OsuMarkdownImage.cs

@@ -0,0 +1,20 @@
+// 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 Markdig.Syntax.Inlines;
+using osu.Framework.Graphics.Containers.Markdown;
+using osu.Framework.Graphics.Cursor;
+
+namespace osu.Game.Graphics.Containers.Markdown
+{
+    public class OsuMarkdownImage : MarkdownImage, IHasTooltip
+    {
+        public string TooltipText { get; }
+
+        public OsuMarkdownImage(LinkInline linkInline)
+            : base(linkInline.Url)
+        {
+            TooltipText = linkInline.Title;
+        }
+    }
+}

osu.Game/Graphics/Containers/Markdown/OsuMarkdownTextFlowContainer.cs

@@ -17,6 +17,8 @@ namespace osu.Game.Graphics.Containers.Markdown
         protected override void AddLinkText(string text, LinkInline linkInline)
             => AddDrawable(new OsuMarkdownLinkText(text, linkInline));
 
+        protected override void AddImage(LinkInline linkInline) => AddDrawable(new OsuMarkdownImage(linkInline));
+
         // TODO : Change font to monospace
         protected override void AddCodeInLine(CodeInline codeInline) => AddDrawable(new OsuMarkdownInlineCode
         {

osu.Game/Graphics/Containers/OsuClickableContainer.cs

@@ -19,7 +19,7 @@ namespace osu.Game.Graphics.Containers
 
         protected virtual HoverClickSounds CreateHoverClickSounds(HoverSampleSet sampleSet) => new HoverClickSounds(sampleSet);
 
-        public OsuClickableContainer(HoverSampleSet sampleSet = HoverSampleSet.Normal)
+        public OsuClickableContainer(HoverSampleSet sampleSet = HoverSampleSet.Default)
         {
             this.sampleSet = sampleSet;
         }

osu.Game/Graphics/Containers/OsuFocusedOverlayContainer.cs

@@ -107,10 +107,10 @@ namespace osu.Game.Graphics.Containers
         {
         }
 
-        private bool playedPopInSound;
-
         protected override void UpdateState(ValueChangedEvent<Visibility> state)
         {
+            bool didChange = state.NewValue != state.OldValue;
+
             switch (state.NewValue)
             {
                 case Visibility.Visible:
@@ -121,18 +121,15 @@ namespace osu.Game.Graphics.Containers
                         return;
                     }
 
-                    samplePopIn?.Play();
-                    playedPopInSound = true;
+                    if (didChange)
+                        samplePopIn?.Play();
 
                     if (BlockScreenWideMouse && DimMainContent) game?.AddBlockingOverlay(this);
                     break;
 
                 case Visibility.Hidden:
-                    if (playedPopInSound)
-                    {
+                    if (didChange)
                         samplePopOut?.Play();
-                        playedPopInSound = false;
-                    }
 
                     if (BlockScreenWideMouse) game?.RemoveBlockingOverlay(this);
                     break;

osu.Game/Graphics/UserInterface/DrawableOsuMenuItem.cs

@@ -3,7 +3,6 @@
 
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
-using osu.Framework.Audio.Sample;
 using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -23,9 +22,6 @@ namespace osu.Game.Graphics.UserInterface
         private const int text_size = 17;
         private const int transition_length = 80;
 
-        private Sample sampleClick;
-        private Sample sampleHover;
-
         private TextContainer text;
 
         public DrawableOsuMenuItem(MenuItem item)
@@ -36,12 +32,11 @@ namespace osu.Game.Graphics.UserInterface
         [BackgroundDependencyLoader]
         private void load(AudioManager audio)
         {
-            sampleHover = audio.Samples.Get(@"UI/generic-hover");
-            sampleClick = audio.Samples.Get(@"UI/generic-select");
-
             BackgroundColour = Color4.Transparent;
             BackgroundColourHover = Color4Extensions.FromHex(@"172023");
 
+            AddInternal(new HoverClickSounds());
+
             updateTextColour();
 
             Item.Action.BindDisabledChanged(_ => updateState(), true);
@@ -84,7 +79,6 @@ namespace osu.Game.Graphics.UserInterface
 
             if (IsHovered && !Item.Action.Disabled)
             {
-                sampleHover.Play();
                 text.BoldText.FadeIn(transition_length, Easing.OutQuint);
                 text.NormalText.FadeOut(transition_length, Easing.OutQuint);
             }
@@ -95,12 +89,6 @@ namespace osu.Game.Graphics.UserInterface
             }
         }
 
-        protected override bool OnClick(ClickEvent e)
-        {
-            sampleClick.Play();
-            return base.OnClick(e);
-        }
-
         protected sealed override Drawable CreateContent() => text = CreateTextContainer();
         protected virtual TextContainer CreateTextContainer() => new TextContainer();
 

osu.Game/Graphics/UserInterface/HoverClickSounds.cs

@@ -28,7 +28,7 @@ namespace osu.Game.Graphics.UserInterface
         /// Array of button codes which should trigger the click sound.
         /// If this optional parameter is omitted or set to <code>null</code>, the click sound will only be played on left click.
         /// </param>
-        public HoverClickSounds(HoverSampleSet sampleSet = HoverSampleSet.Normal, MouseButton[] buttons = null)
+        public HoverClickSounds(HoverSampleSet sampleSet = HoverSampleSet.Default, MouseButton[] buttons = null)
             : base(sampleSet)
         {
             this.buttons = buttons ?? new[] { MouseButton.Left };
@@ -45,7 +45,8 @@ namespace osu.Game.Graphics.UserInterface
         [BackgroundDependencyLoader]
         private void load(AudioManager audio)
         {
-            sampleClick = audio.Samples.Get($@"UI/generic-select{SampleSet.GetDescription()}");
+            sampleClick = audio.Samples.Get($@"UI/{SampleSet.GetDescription()}-select")
+                          ?? audio.Samples.Get($@"UI/{HoverSampleSet.Default.GetDescription()}-select");
         }
     }
 }

osu.Game/Graphics/UserInterface/HoverSampleSet.cs

@@ -0,0 +1,25 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System.ComponentModel;
+
+namespace osu.Game.Graphics.UserInterface
+{
+    public enum HoverSampleSet
+    {
+        [Description("default")]
+        Default,
+
+        [Description("button")]
+        Button,
+
+        [Description("softer")]
+        Soft,
+
+        [Description("toolbar")]
+        Toolbar,
+
+        [Description("songselect")]
+        SongSelect
+    }
+}

osu.Game/Graphics/UserInterface/HoverSounds.cs

@@ -1,7 +1,6 @@
 // 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.Allocation;
 using osu.Framework.Audio;
 using osu.Framework.Audio.Sample;
@@ -22,7 +21,7 @@ namespace osu.Game.Graphics.UserInterface
 
         protected readonly HoverSampleSet SampleSet;
 
-        public HoverSounds(HoverSampleSet sampleSet = HoverSampleSet.Normal)
+        public HoverSounds(HoverSampleSet sampleSet = HoverSampleSet.Default)
         {
             SampleSet = sampleSet;
             RelativeSizeAxes = Axes.Both;
@@ -31,7 +30,8 @@ namespace osu.Game.Graphics.UserInterface
         [BackgroundDependencyLoader]
         private void load(AudioManager audio, SessionStatics statics)
         {
-            sampleHover = audio.Samples.Get($@"UI/generic-hover{SampleSet.GetDescription()}");
+            sampleHover = audio.Samples.Get($@"UI/{SampleSet.GetDescription()}-hover")
+                          ?? audio.Samples.Get($@"UI/{HoverSampleSet.Default.GetDescription()}-hover");
         }
 
         public override void PlayHoverSample()
@@ -40,22 +40,4 @@ namespace osu.Game.Graphics.UserInterface
             sampleHover.Play();
         }
     }
-
-    public enum HoverSampleSet
-    {
-        [Description("")]
-        Loud,
-
-        [Description("-soft")]
-        Normal,
-
-        [Description("-softer")]
-        Soft,
-
-        [Description("-toolbar")]
-        Toolbar,
-
-        [Description("-songselect")]
-        SongSelect
-    }
 }

osu.Game/Graphics/UserInterface/OsuAnimatedButton.cs

@@ -44,6 +44,7 @@ namespace osu.Game.Graphics.UserInterface
         private readonly Box hover;
 
         public OsuAnimatedButton()
+            : base(HoverSampleSet.Button)
         {
             base.Content.Add(content = new Container
             {

osu.Game/Graphics/UserInterface/OsuButton.cs

@@ -49,7 +49,7 @@ namespace osu.Game.Graphics.UserInterface
         protected Box Background;
         protected SpriteText SpriteText;
 
-        public OsuButton(HoverSampleSet? hoverSounds = HoverSampleSet.Loud)
+        public OsuButton(HoverSampleSet? hoverSounds = HoverSampleSet.Button)
         {
             Height = 40;
 

osu.Game/Graphics/UserInterface/OsuTabControl.cs

@@ -160,7 +160,7 @@ namespace osu.Game.Graphics.UserInterface
                         Margin = new MarginPadding { Top = 5, Bottom = 5 },
                         Origin = Anchor.BottomLeft,
                         Anchor = Anchor.BottomLeft,
-                        Text = (value as IHasDescription)?.Description ?? (value as Enum)?.GetDescription() ?? value.ToString(),
+                        Text = (value as IHasDescription)?.Description ?? (value as Enum)?.GetLocalisableDescription() ?? value.ToString(),
                         Font = OsuFont.GetFont(size: 14)
                     },
                     Bar = new Box

osu.Game/Graphics/UserInterface/PageTabControl.cs

@@ -11,6 +11,7 @@ using osu.Framework.Graphics.Shapes;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Graphics.UserInterface;
 using osu.Framework.Input.Events;
+using osu.Framework.Localisation;
 using osu.Game.Graphics.Sprites;
 
 namespace osu.Game.Graphics.UserInterface
@@ -81,7 +82,7 @@ namespace osu.Game.Graphics.UserInterface
                 Active.BindValueChanged(active => Text.Font = Text.Font.With(Typeface.Torus, weight: active.NewValue ? FontWeight.Bold : FontWeight.Medium), true);
             }
 
-            protected virtual string CreateText() => (Value as Enum)?.GetDescription() ?? Value.ToString();
+            protected virtual LocalisableString CreateText() => (Value as Enum)?.GetLocalisableDescription() ?? Value.ToString();
 
             protected override bool OnHover(HoverEvent e)
             {

osu.Game/Graphics/UserInterfaceV2/LabelledDrawable.cs

@@ -14,6 +14,27 @@ namespace osu.Game.Graphics.UserInterfaceV2
     public abstract class LabelledDrawable<T> : CompositeDrawable
         where T : Drawable
     {
+        private float? fixedLabelWidth;
+
+        /// <summary>
+        /// The fixed width of the label of this <see cref="LabelledDrawable{T}"/>.
+        /// If <c>null</c>, the label portion will auto-size to its content.
+        /// Can be used in layout scenarios where several labels must match in length for the components to be aligned properly.
+        /// </summary>
+        public float? FixedLabelWidth
+        {
+            get => fixedLabelWidth;
+            set
+            {
+                if (fixedLabelWidth == value)
+                    return;
+
+                fixedLabelWidth = value;
+
+                updateLabelWidth();
+            }
+        }
+
         protected const float CONTENT_PADDING_VERTICAL = 10;
         protected const float CONTENT_PADDING_HORIZONTAL = 15;
         protected const float CORNER_RADIUS = 15;
@@ -23,6 +44,7 @@ namespace osu.Game.Graphics.UserInterfaceV2
         /// </summary>
         protected readonly T Component;
 
+        private readonly GridContainer grid;
         private readonly OsuTextFlowContainer labelText;
         private readonly OsuTextFlowContainer descriptionText;
 
@@ -56,7 +78,7 @@ namespace osu.Game.Graphics.UserInterfaceV2
                     Spacing = new Vector2(0, 12),
                     Children = new Drawable[]
                     {
-                        new GridContainer
+                        grid = new GridContainer
                         {
                             RelativeSizeAxes = Axes.X,
                             AutoSizeAxes = Axes.Y,
@@ -69,7 +91,13 @@ namespace osu.Game.Graphics.UserInterfaceV2
                                         Anchor = Anchor.CentreLeft,
                                         Origin = Anchor.CentreLeft,
                                         AutoSizeAxes = Axes.Both,
-                                        Padding = new MarginPadding { Right = 20 }
+                                        Padding = new MarginPadding
+                                        {
+                                            Right = 20,
+                                            // ensure that the label is always vertically padded even if the component itself isn't.
+                                            // this may become an issue if the label is taller than the component.
+                                            Vertical = padded ? 0 : CONTENT_PADDING_VERTICAL
+                                        }
                                     },
                                     new Container
                                     {
@@ -87,7 +115,6 @@ namespace osu.Game.Graphics.UserInterfaceV2
                                 },
                             },
                             RowDimensions = new[] { new Dimension(GridSizeMode.AutoSize) },
-                            ColumnDimensions = new[] { new Dimension(GridSizeMode.AutoSize) }
                         },
                         descriptionText = new OsuTextFlowContainer(s => s.Font = OsuFont.GetFont(size: 12, weight: FontWeight.Bold, italics: true))
                         {
@@ -99,6 +126,24 @@ namespace osu.Game.Graphics.UserInterfaceV2
                     }
                 }
             };
+
+            updateLabelWidth();
+        }
+
+        private void updateLabelWidth()
+        {
+            if (fixedLabelWidth == null)
+            {
+                grid.ColumnDimensions = new[] { new Dimension(GridSizeMode.AutoSize) };
+                labelText.RelativeSizeAxes = Axes.None;
+                labelText.AutoSizeAxes = Axes.Both;
+            }
+            else
+            {
+                grid.ColumnDimensions = new[] { new Dimension(GridSizeMode.Absolute, fixedLabelWidth.Value) };
+                labelText.AutoSizeAxes = Axes.Y;
+                labelText.RelativeSizeAxes = Axes.X;
+            }
         }
 
         [BackgroundDependencyLoader]

osu.Game/Graphics/UserInterfaceV2/LabelledTextBox.cs

@@ -21,6 +21,7 @@ namespace osu.Game.Graphics.UserInterfaceV2
 
         public bool ReadOnly
         {
+            get => Component.ReadOnly;
             set => Component.ReadOnly = value;
         }
 
@@ -45,14 +46,7 @@ namespace osu.Game.Graphics.UserInterfaceV2
             Component.BorderColour = colours.Blue;
         }
 
-        protected virtual OsuTextBox CreateTextBox() => new OsuTextBox
-        {
-            CommitOnFocusLost = true,
-            Anchor = Anchor.Centre,
-            Origin = Anchor.Centre,
-            RelativeSizeAxes = Axes.X,
-            CornerRadius = CORNER_RADIUS,
-        };
+        protected virtual OsuTextBox CreateTextBox() => new OsuTextBox();
 
         public override bool AcceptsFocus => true;
 
@@ -64,6 +58,12 @@ namespace osu.Game.Graphics.UserInterfaceV2
 
         protected override OsuTextBox CreateComponent() => CreateTextBox().With(t =>
         {
+            t.CommitOnFocusLost = true;
+            t.Anchor = Anchor.Centre;
+            t.Origin = Anchor.Centre;
+            t.RelativeSizeAxes = Axes.X;
+            t.CornerRadius = CORNER_RADIUS;
+
             t.OnCommit += (sender, newText) => OnCommit?.Invoke(sender, newText);
         });
     }

osu.Game/Localisation/ChatStrings.cs

@@ -7,17 +7,17 @@ namespace osu.Game.Localisation
 {
     public static class ChatStrings
     {
-        private const string prefix = "osu.Game.Localisation.Chat";
+        private const string prefix = @"osu.Game.Localisation.Chat";
 
         /// <summary>
         /// "chat"
         /// </summary>
-        public static LocalisableString HeaderTitle => new TranslatableString(getKey("header_title"), "chat");
+        public static LocalisableString HeaderTitle => new TranslatableString(getKey(@"header_title"), @"chat");
 
         /// <summary>
         /// "join the real-time discussion"
         /// </summary>
-        public static LocalisableString HeaderDescription => new TranslatableString(getKey("header_description"), "join the real-time discussion");
+        public static LocalisableString HeaderDescription => new TranslatableString(getKey(@"header_description"), @"join the real-time discussion");
 
         private static string getKey(string key) => $"{prefix}:{key}";
     }

osu.Game/Localisation/CommonStrings.cs

@@ -7,12 +7,12 @@ namespace osu.Game.Localisation
 {
     public static class CommonStrings
     {
-        private const string prefix = "osu.Game.Localisation.Common";
+        private const string prefix = @"osu.Game.Localisation.Common";
 
         /// <summary>
         /// "Cancel"
         /// </summary>
-        public static LocalisableString Cancel => new TranslatableString(getKey("cancel"), "Cancel");
+        public static LocalisableString Cancel => new TranslatableString(getKey(@"cancel"), @"Cancel");
 
         private static string getKey(string key) => $"{prefix}:{key}";
     }

osu.Game/Localisation/Language.cs

@@ -7,10 +7,107 @@ namespace osu.Game.Localisation
 {
     public enum Language
     {
-        [Description("English")]
+        [Description(@"English")]
         en,
 
-        [Description("日本語")]
-        ja
+        // TODO: Requires Arabic glyphs to be added to resources (and possibly also RTL support).
+        // [Description(@"اَلْعَرَبِيَّةُ")]
+        // ar,
+
+        // TODO: Some accented glyphs are missing. Revisit when adding Inter.
+        // [Description(@"Беларуская мова")]
+        // be,
+
+        [Description(@"Български")]
+        bg,
+
+        [Description(@"Česky")]
+        cs,
+
+        [Description(@"Dansk")]
+        da,
+
+        [Description(@"Deutsch")]
+        de,
+
+        // TODO: Some accented glyphs are missing. Revisit when adding Inter.
+        // [Description(@"Ελληνικά")]
+        // el,
+
+        [Description(@"español")]
+        es,
+
+        [Description(@"Suomi")]
+        fi,
+
+        [Description(@"français")]
+        fr,
+
+        [Description(@"Magyar")]
+        hu,
+
+        [Description(@"Bahasa Indonesia")]
+        id,
+
+        [Description(@"Italiano")]
+        it,
+
+        [Description(@"日本語")]
+        ja,
+
+        [Description(@"한국어")]
+        ko,
+
+        [Description(@"Nederlands")]
+        nl,
+
+        [Description(@"Norsk")]
+        no,
+
+        [Description(@"polski")]
+        pl,
+
+        [Description(@"Português")]
+        pt,
+
+        [Description(@"Português (Brasil)")]
+        pt_br,
+
+        [Description(@"Română")]
+        ro,
+
+        [Description(@"Русский")]
+        ru,
+
+        [Description(@"Slovenčina")]
+        sk,
+
+        [Description(@"Svenska")]
+        sv,
+
+        [Description(@"ไทย")]
+        th,
+
+        [Description(@"Tagalog")]
+        tl,
+
+        [Description(@"Türkçe")]
+        tr,
+
+        // TODO: Some accented glyphs are missing. Revisit when adding Inter.
+        // [Description(@"Українська мова")]
+        // uk,
+
+        [Description(@"Tiếng Việt")]
+        vi,
+
+        [Description(@"简体中文")]
+        zh,
+
+        [Description(@"繁體中文（香港）")]
+        zh_hk,
+
+        [Description(@"繁體中文（台灣）")]
+        zh_tw
     }
 }

osu.Game/Localisation/NotificationsStrings.cs

@@ -7,17 +7,17 @@ namespace osu.Game.Localisation
 {
     public static class NotificationsStrings
     {
-        private const string prefix = "osu.Game.Localisation.Notifications";
+        private const string prefix = @"osu.Game.Localisation.Notifications";
 
         /// <summary>
         /// "notifications"
         /// </summary>
-        public static LocalisableString HeaderTitle => new TranslatableString(getKey("header_title"), "notifications");
+        public static LocalisableString HeaderTitle => new TranslatableString(getKey(@"header_title"), @"notifications");
 
         /// <summary>
         /// "waiting for 'ya"
         /// </summary>
-        public static LocalisableString HeaderDescription => new TranslatableString(getKey("header_description"), "waiting for 'ya");
+        public static LocalisableString HeaderDescription => new TranslatableString(getKey(@"header_description"), @"waiting for 'ya");
 
         private static string getKey(string key) => $"{prefix}:{key}";
     }

osu.Game/Localisation/NowPlayingStrings.cs

@@ -7,17 +7,17 @@ namespace osu.Game.Localisation
 {
     public static class NowPlayingStrings
     {
-        private const string prefix = "osu.Game.Localisation.NowPlaying";
+        private const string prefix = @"osu.Game.Localisation.NowPlaying";
 
         /// <summary>
         /// "now playing"
         /// </summary>
-        public static LocalisableString HeaderTitle => new TranslatableString(getKey("header_title"), "now playing");
+        public static LocalisableString HeaderTitle => new TranslatableString(getKey(@"header_title"), @"now playing");
 
         /// <summary>
         /// "manage the currently playing track"
         /// </summary>
-        public static LocalisableString HeaderDescription => new TranslatableString(getKey("header_description"), "manage the currently playing track");
+        public static LocalisableString HeaderDescription => new TranslatableString(getKey(@"header_description"), @"manage the currently playing track");
 
         private static string getKey(string key) => $"{prefix}:{key}";
     }

osu.Game/Localisation/ResourceManagerLocalisationStore.cs

@@ -5,6 +5,7 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using System.IO;
+using System.Linq;
 using System.Resources;
 using System.Threading.Tasks;
 using osu.Framework.Localisation;
@@ -34,7 +35,29 @@ namespace osu.Game.Localisation
             lock (resourceManagers)
             {
                 if (!resourceManagers.TryGetValue(ns, out var manager))
-                    resourceManagers[ns] = manager = new ResourceManager(ns, GetType().Assembly);
+                {
+                    var loadedAssemblies = AppDomain.CurrentDomain.GetAssemblies();
+
+                    // Traverse backwards through periods in the namespace to find a matching assembly.
+                    string assemblyName = ns;
+
+                    while (!string.IsNullOrEmpty(assemblyName))
+                    {
+                        var matchingAssembly = loadedAssemblies.FirstOrDefault(asm => asm.GetName().Name == assemblyName);
+
+                        if (matchingAssembly != null)
+                        {
+                            resourceManagers[ns] = manager = new ResourceManager(ns, matchingAssembly);
+                            break;
+                        }
+
+                        int lastIndex = Math.Max(0, assemblyName.LastIndexOf('.'));
+                        assemblyName = assemblyName.Substring(0, lastIndex);
+                    }
+                }
+
+                if (manager == null)
+                    return null;
 
                 try
                 {

osu.Game/Localisation/SettingsStrings.cs

@@ -7,17 +7,17 @@ namespace osu.Game.Localisation
 {
     public static class SettingsStrings
     {
-        private const string prefix = "osu.Game.Localisation.Settings";
+        private const string prefix = @"osu.Game.Localisation.Settings";
 
         /// <summary>
         /// "settings"
         /// </summary>
-        public static LocalisableString HeaderTitle => new TranslatableString(getKey("header_title"), "settings");
+        public static LocalisableString HeaderTitle => new TranslatableString(getKey(@"header_title"), @"settings");
 
         /// <summary>
         /// "change the way osu! behaves"
         /// </summary>
-        public static LocalisableString HeaderDescription => new TranslatableString(getKey("header_description"), "change the way osu! behaves");
+        public static LocalisableString HeaderDescription => new TranslatableString(getKey(@"header_description"), @"change the way osu! behaves");
 
         private static string getKey(string key) => $"{prefix}:{key}";
     }

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

@@ -11,11 +11,11 @@ namespace osu.Game.Online.API.Requests
 {
     public class CreateChannelRequest : APIRequest<APIChatChannel>
     {
-        private readonly Channel channel;
+        public readonly Channel Channel;
 
         public CreateChannelRequest(Channel channel)
         {
-            this.channel = channel;
+            Channel = channel;
         }
 
         protected override WebRequest CreateWebRequest()
@@ -24,7 +24,7 @@ namespace osu.Game.Online.API.Requests
             req.Method = HttpMethod.Post;
 
             req.AddParameter("type", $"{ChannelType.PM}");
-            req.AddParameter("target_id", $"{channel.Users.First().Id}");
+            req.AddParameter("target_id", $"{Channel.Users.First().Id}");
 
             return req;
         }

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

@@ -21,7 +21,12 @@ namespace osu.Game.Online.API.Requests.Responses
         {
             var ruleset = rulesets.GetRuleset(OnlineRulesetID);
 
-            var mods = Mods != null ? ruleset.CreateInstance().GetAllMods().Where(mod => Mods.Contains(mod.Acronym)).ToArray() : Array.Empty<Mod>();
+            var rulesetInstance = ruleset.CreateInstance();
+
+            var mods = Mods != null ? rulesetInstance.GetAllMods().Where(mod => Mods.Contains(mod.Acronym)).ToArray() : Array.Empty<Mod>();
+
+            // all API scores provided by this class are considered to be legacy.
+            mods = mods.Append(rulesetInstance.GetAllMods().OfType<ModClassic>().Single()).ToArray();
 
             var scoreInfo = new ScoreInfo
             {
@@ -38,7 +43,6 @@ namespace osu.Game.Online.API.Requests.Responses
                 Rank = Rank,
                 Ruleset = ruleset,
                 Mods = mods,
-                IsLegacyScore = true
             };
 
             if (Statistics != null)

osu.Game/Online/Chat/Message.cs

@@ -63,5 +63,7 @@ namespace osu.Game.Online.Chat
 
         // ReSharper disable once ImpureMethodCallOnReadonlyValueField
         public override int GetHashCode() => Id.GetHashCode();
+
+        public override string ToString() => $"[{ChannelId}] ({Id}) {Sender}: {Content}";
     }
 }

osu.Game/Online/Chat/MessageNotifier.cs

@@ -0,0 +1,181 @@
+// 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.Collections.Specialized;
+using System.Linq;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Sprites;
+using osu.Game.Configuration;
+using osu.Game.Graphics;
+using osu.Game.Online.API;
+using osu.Game.Overlays;
+using osu.Game.Overlays.Notifications;
+using osu.Game.Users;
+
+namespace osu.Game.Online.Chat
+{
+    /// <summary>
+    /// Component that handles creating and posting notifications for incoming messages.
+    /// </summary>
+    public class MessageNotifier : Component
+    {
+        [Resolved]
+        private NotificationOverlay notifications { get; set; }
+
+        [Resolved]
+        private ChatOverlay chatOverlay { get; set; }
+
+        [Resolved]
+        private ChannelManager channelManager { get; set; }
+
+        private Bindable<bool> notifyOnUsername;
+        private Bindable<bool> notifyOnPrivateMessage;
+
+        private readonly IBindable<User> localUser = new Bindable<User>();
+        private readonly IBindableList<Channel> joinedChannels = new BindableList<Channel>();
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config, IAPIProvider api)
+        {
+            notifyOnUsername = config.GetBindable<bool>(OsuSetting.NotifyOnUsernameMentioned);
+            notifyOnPrivateMessage = config.GetBindable<bool>(OsuSetting.NotifyOnPrivateMessage);
+
+            localUser.BindTo(api.LocalUser);
+            joinedChannels.BindTo(channelManager.JoinedChannels);
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+            joinedChannels.BindCollectionChanged(channelsChanged, true);
+        }
+
+        private void channelsChanged(object sender, NotifyCollectionChangedEventArgs e)
+        {
+            switch (e.Action)
+            {
+                case NotifyCollectionChangedAction.Add:
+                    foreach (var channel in e.NewItems.Cast<Channel>())
+                        channel.NewMessagesArrived += checkNewMessages;
+
+                    break;
+
+                case NotifyCollectionChangedAction.Remove:
+                    foreach (var channel in e.OldItems.Cast<Channel>())
+                        channel.NewMessagesArrived -= checkNewMessages;
+
+                    break;
+            }
+        }
+
+        private void checkNewMessages(IEnumerable<Message> messages)
+        {
+            if (!messages.Any())
+                return;
+
+            var channel = channelManager.JoinedChannels.SingleOrDefault(c => c.Id == messages.First().ChannelId);
+
+            if (channel == null)
+                return;
+
+            // Only send notifications, if ChatOverlay and the target channel aren't visible.
+            if (chatOverlay.IsPresent && channelManager.CurrentChannel.Value == channel)
+                return;
+
+            foreach (var message in messages.OrderByDescending(m => m.Id))
+            {
+                // ignore messages that already have been read
+                if (message.Id <= channel.LastReadId)
+                    return;
+
+                if (message.Sender.Id == localUser.Value.Id)
+                    continue;
+
+                // check for private messages first to avoid both posting two notifications about the same message
+                if (checkForPMs(channel, message))
+                    continue;
+
+                checkForMentions(channel, message);
+            }
+        }
+
+        /// <summary>
+        /// Checks whether the user enabled private message notifications and whether specified <paramref name="message"/> is a direct message.
+        /// </summary>
+        /// <param name="channel">The channel associated to the <paramref name="message"/></param>
+        /// <param name="message">The message to be checked</param>
+        /// <returns>Whether a notification was fired.</returns>
+        private bool checkForPMs(Channel channel, Message message)
+        {
+            if (!notifyOnPrivateMessage.Value || channel.Type != ChannelType.PM)
+                return false;
+
+            notifications.Post(new PrivateMessageNotification(message.Sender.Username, channel));
+            return true;
+        }
+
+        private void checkForMentions(Channel channel, Message message)
+        {
+            if (!notifyOnUsername.Value || !checkContainsUsername(message.Content, localUser.Value.Username)) return;
+
+            notifications.Post(new MentionNotification(message.Sender.Username, channel));
+        }
+
+        /// <summary>
+        /// Checks if <paramref name="message"/> contains <paramref name="username"/>.
+        /// This will match against the case where underscores are used instead of spaces (which is how osu-stable handles usernames with spaces).
+        /// </summary>
+        private static bool checkContainsUsername(string message, string username) => message.Contains(username, StringComparison.OrdinalIgnoreCase) || message.Contains(username.Replace(' ', '_'), StringComparison.OrdinalIgnoreCase);
+
+        public class PrivateMessageNotification : OpenChannelNotification
+        {
+            public PrivateMessageNotification(string username, Channel channel)
+                : base(channel)
+            {
+                Icon = FontAwesome.Solid.Envelope;
+                Text = $"You received a private message from '{username}'. Click to read it!";
+            }
+        }
+
+        public class MentionNotification : OpenChannelNotification
+        {
+            public MentionNotification(string username, Channel channel)
+                : base(channel)
+            {
+                Icon = FontAwesome.Solid.At;
+                Text = $"Your name was mentioned in chat by '{username}'. Click to find out why!";
+            }
+        }
+
+        public abstract class OpenChannelNotification : SimpleNotification
+        {
+            protected OpenChannelNotification(Channel channel)
+            {
+                this.channel = channel;
+            }
+
+            private readonly Channel channel;
+
+            public override bool IsImportant => false;
+
+            [BackgroundDependencyLoader]
+            private void load(OsuColour colours, ChatOverlay chatOverlay, NotificationOverlay notificationOverlay, ChannelManager channelManager)
+            {
+                IconBackgound.Colour = colours.PurpleDark;
+
+                Activated = delegate
+                {
+                    notificationOverlay.Hide();
+                    chatOverlay.Show();
+                    channelManager.CurrentChannel.Value = channel;
+
+                    return true;
+                };
+            }
+        }
+    }
+}

osu.Game/Online/Leaderboards/Leaderboard.cs

@@ -44,9 +44,9 @@ namespace osu.Game.Online.Leaderboards
 
         protected override Container<Drawable> Content => content;
 
-        private IEnumerable<TScoreInfo> scores;
+        private ICollection<TScoreInfo> scores;
 
-        public IEnumerable<TScoreInfo> Scores
+        public ICollection<TScoreInfo> Scores
         {
             get => scores;
             set
@@ -126,7 +126,7 @@ namespace osu.Game.Online.Leaderboards
                     return;
 
                 scope = value;
-                UpdateScores();
+                RefreshScores();
             }
         }
 
@@ -154,7 +154,7 @@ namespace osu.Game.Online.Leaderboards
                     case PlaceholderState.NetworkFailure:
                         replacePlaceholder(new ClickablePlaceholder(@"Couldn't fetch scores!", FontAwesome.Solid.Sync)
                         {
-                            Action = UpdateScores,
+                            Action = RefreshScores
                         });
                         break;
 
@@ -254,8 +254,6 @@ namespace osu.Game.Online.Leaderboards
             apiState.BindValueChanged(onlineStateChanged, true);
         }
 
-        public void RefreshScores() => UpdateScores();
-
         private APIRequest getScoresRequest;
 
         protected abstract bool IsOnlineScope { get; }
@@ -267,12 +265,14 @@ namespace osu.Game.Online.Leaderboards
                 case APIState.Online:
                 case APIState.Offline:
                     if (IsOnlineScope)
-                        UpdateScores();
+                        RefreshScores();
 
                     break;
             }
         });
 
+        public void RefreshScores() => Scheduler.AddOnce(UpdateScores);
+
         protected void UpdateScores()
         {
             // don't display any scores or placeholder until the first Scores_Set has been called.
@@ -290,7 +290,7 @@ namespace osu.Game.Online.Leaderboards
 
                 getScoresRequest = FetchScores(scores => Schedule(() =>
                 {
-                    Scores = scores;
+                    Scores = scores.ToArray();
                     PlaceholderState = Scores.Any() ? PlaceholderState.Successful : PlaceholderState.NoScores;
                 }));
 

osu.Game/Online/Multiplayer/MultiplayerRoomSettings.cs

@@ -6,7 +6,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using JetBrains.Annotations;
 using MessagePack;
 using osu.Game.Online.API;
 
@@ -28,11 +27,9 @@ namespace osu.Game.Online.Multiplayer
         [Key(3)]
         public string Name { get; set; } = "Unnamed room";
 
-        [NotNull]
         [Key(4)]
         public IEnumerable<APIMod> RequiredMods { get; set; } = Enumerable.Empty<APIMod>();
 
-        [NotNull]
         [Key(5)]
         public IEnumerable<APIMod> AllowedMods { get; set; } = Enumerable.Empty<APIMod>();
 

osu.Game/Online/Multiplayer/MultiplayerRoomUser.cs

@@ -6,7 +6,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using JetBrains.Annotations;
 using MessagePack;
 using Newtonsoft.Json;
 using osu.Game.Online.API;
@@ -35,7 +34,6 @@ namespace osu.Game.Online.Multiplayer
         /// Any mods applicable only to the local user.
         /// </summary>
         [Key(3)]
-        [NotNull]
         public IEnumerable<APIMod> Mods { get; set; } = Enumerable.Empty<APIMod>();
 
         [IgnoreMember]

osu.Game/OsuGame.cs

@@ -50,8 +50,10 @@ using osu.Game.Updater;
 using osu.Game.Utils;
 using LogLevel = osu.Framework.Logging.LogLevel;
 using osu.Game.Database;
+using osu.Game.Extensions;
 using osu.Game.IO;
 using osu.Game.Localisation;
+using osu.Game.Performance;
 using osu.Game.Skinning.Editor;
 
 namespace osu.Game
@@ -426,9 +428,12 @@ namespace osu.Game
         {
             // The given ScoreInfo may have missing properties if it was retrieved from online data. Re-retrieve it from the database
             // to ensure all the required data for presenting a replay are present.
-            var databasedScoreInfo = score.OnlineScoreID != null
-                ? ScoreManager.Query(s => s.OnlineScoreID == score.OnlineScoreID)
-                : ScoreManager.Query(s => s.Hash == score.Hash);
+            ScoreInfo databasedScoreInfo = null;
+
+            if (score.OnlineScoreID != null)
+                databasedScoreInfo = ScoreManager.Query(s => s.OnlineScoreID == score.OnlineScoreID);
+
+            databasedScoreInfo ??= ScoreManager.Query(s => s.Hash == score.Hash);
 
             if (databasedScoreInfo == null)
             {
@@ -484,6 +489,8 @@ namespace osu.Game
 
         protected virtual UpdateManager CreateUpdateManager() => new UpdateManager();
 
+        protected virtual HighPerformanceSession CreateHighPerformanceSession() => new HighPerformanceSession();
+
         protected override Container CreateScalingContainer() => new ScalingContainer(ScalingMode.Everything);
 
         #region Beatmap progression
@@ -577,7 +584,7 @@ namespace osu.Game
 
             foreach (var language in Enum.GetValues(typeof(Language)).OfType<Language>())
             {
-                var cultureCode = language.ToString();
+                var cultureCode = language.ToCultureCode();
                 Localisation.AddLanguage(cultureCode, new ResourceManagerLocalisationStore(cultureCode));
             }
 
@@ -651,9 +658,10 @@ namespace osu.Game
                                     Origin = Anchor.BottomLeft,
                                     Action = () =>
                                     {
-                                        var currentScreen = ScreenStack.CurrentScreen as IOsuScreen;
+                                        if (!(ScreenStack.CurrentScreen is IOsuScreen currentScreen))
+                                            return;
 
-                                        if (currentScreen?.AllowBackButton == true && !currentScreen.OnBackButton())
+                                        if (!((Drawable)currentScreen).IsLoaded || (currentScreen.AllowBackButton && !currentScreen.OnBackButton()))
                                             ScreenStack.Exit();
                                     }
                                 },
@@ -711,7 +719,6 @@ namespace osu.Game
                 PostNotification = n => notifications.Post(n),
             }, Add, true);
 
-            loadComponentSingleFile(difficultyRecommender, Add);
             loadComponentSingleFile(stableImportManager, Add);
 
             loadComponentSingleFile(screenshotManager, Add);
@@ -727,6 +734,7 @@ namespace osu.Game
             var rankingsOverlay = loadComponentSingleFile(new RankingsOverlay(), overlayContent.Add, true);
             loadComponentSingleFile(channelManager = new ChannelManager(), AddInternal, true);
             loadComponentSingleFile(chatOverlay = new ChatOverlay(), overlayContent.Add, true);
+            loadComponentSingleFile(new MessageNotifier(), AddInternal, true);
             loadComponentSingleFile(Settings = new SettingsOverlay { GetToolbarHeight = () => ToolbarOffset }, leftFloatingOverlayContent.Add, true);
             var changelogOverlay = loadComponentSingleFile(new ChangelogOverlay(), overlayContent.Add, true);
             loadComponentSingleFile(userProfile = new UserProfileOverlay(), overlayContent.Add, true);
@@ -751,8 +759,11 @@ namespace osu.Game
             loadComponentSingleFile(new AccountCreationOverlay(), topMostOverlayContent.Add, true);
             loadComponentSingleFile(new DialogOverlay(), topMostOverlayContent.Add, true);
 
+            loadComponentSingleFile(CreateHighPerformanceSession(), Add);
+
             chatOverlay.State.ValueChanged += state => channelManager.HighPollRate.Value = state.NewValue == Visibility.Visible;
 
+            Add(difficultyRecommender);
             Add(externalLinkOpener = new ExternalLinkOpener());
             Add(new MusicKeyBindingHandler());
 

osu.Game/Overlays/BeatmapListing/BeatmapListingSearchControl.cs

@@ -14,6 +14,7 @@ using osu.Game.Beatmaps;
 using osu.Game.Configuration;
 using osu.Game.Graphics.Containers;
 using osu.Game.Graphics.UserInterface;
+using osu.Game.Resources.Localisation.Web;
 using osuTK.Graphics;
 using osu.Game.Rulesets;
 using osu.Game.Scoring;
@@ -126,15 +127,15 @@ namespace osu.Game.Overlays.BeatmapListing
                                 Padding = new MarginPadding { Horizontal = 10 },
                                 Children = new Drawable[]
                                 {
-                                    generalFilter = new BeatmapSearchMultipleSelectionFilterRow<SearchGeneral>(@"General"),
+                                    generalFilter = new BeatmapSearchMultipleSelectionFilterRow<SearchGeneral>(BeatmapsStrings.ListingSearchFiltersGeneral),
                                     modeFilter = new BeatmapSearchRulesetFilterRow(),
-                                    categoryFilter = new BeatmapSearchFilterRow<SearchCategory>(@"Categories"),
-                                    genreFilter = new BeatmapSearchFilterRow<SearchGenre>(@"Genre"),
-                                    languageFilter = new BeatmapSearchFilterRow<SearchLanguage>(@"Language"),
-                                    extraFilter = new BeatmapSearchMultipleSelectionFilterRow<SearchExtra>(@"Extra"),
+                                    categoryFilter = new BeatmapSearchFilterRow<SearchCategory>(BeatmapsStrings.ListingSearchFiltersStatus),
+                                    genreFilter = new BeatmapSearchFilterRow<SearchGenre>(BeatmapsStrings.ListingSearchFiltersGenre),
+                                    languageFilter = new BeatmapSearchFilterRow<SearchLanguage>(BeatmapsStrings.ListingSearchFiltersLanguage),
+                                    extraFilter = new BeatmapSearchMultipleSelectionFilterRow<SearchExtra>(BeatmapsStrings.ListingSearchFiltersExtra),
                                     ranksFilter = new BeatmapSearchScoreFilterRow(),
-                                    playedFilter = new BeatmapSearchFilterRow<SearchPlayed>(@"Played"),
-                                    explicitContentFilter = new BeatmapSearchFilterRow<SearchExplicit>(@"Explicit Content"),
+                                    playedFilter = new BeatmapSearchFilterRow<SearchPlayed>(BeatmapsStrings.ListingSearchFiltersPlayed),
+                                    explicitContentFilter = new BeatmapSearchFilterRow<SearchExplicit>(BeatmapsStrings.ListingSearchFiltersNsfw),
                                 }
                             }
                         }
@@ -172,7 +173,7 @@ namespace osu.Game.Overlays.BeatmapListing
 
             public BeatmapSearchTextBox()
             {
-                PlaceholderText = @"type in keywords...";
+                PlaceholderText = BeatmapsStrings.ListingSearchPrompt;
             }
 
             protected override bool OnKeyDown(KeyDownEvent e)

osu.Game/Overlays/BeatmapListing/BeatmapSearchFilterRow.cs

@@ -11,8 +11,8 @@ using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Graphics.UserInterface;
 using osuTK;
-using Humanizer;
 using osu.Framework.Extensions.EnumExtensions;
+using osu.Framework.Localisation;
 
 namespace osu.Game.Overlays.BeatmapListing
 {
@@ -26,7 +26,7 @@ namespace osu.Game.Overlays.BeatmapListing
             set => current.Current = value;
         }
 
-        public BeatmapSearchFilterRow(string headerName)
+        public BeatmapSearchFilterRow(LocalisableString header)
         {
             Drawable filter;
             AutoSizeAxes = Axes.Y;
@@ -53,7 +53,7 @@ namespace osu.Game.Overlays.BeatmapListing
                             Anchor = Anchor.BottomLeft,
                             Origin = Anchor.BottomLeft,
                             Font = OsuFont.GetFont(size: 13),
-                            Text = headerName.Titleize()
+                            Text = header
                         },
                         filter = CreateFilter()
                     }

osu.Game/Overlays/BeatmapListing/BeatmapSearchMultipleSelectionFilterRow.cs

@@ -9,6 +9,7 @@ using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Input.Events;
+using osu.Framework.Localisation;
 using osuTK;
 
 namespace osu.Game.Overlays.BeatmapListing
@@ -19,8 +20,8 @@ namespace osu.Game.Overlays.BeatmapListing
 
         private MultipleSelectionFilter filter;
 
-        public BeatmapSearchMultipleSelectionFilterRow(string headerName)
-            : base(headerName)
+        public BeatmapSearchMultipleSelectionFilterRow(LocalisableString header)
+            : base(header)
         {
             Current.BindTo(filter.Current);
         }

osu.Game/Overlays/BeatmapListing/BeatmapSearchRulesetFilterRow.cs

@@ -3,6 +3,7 @@
 
 using osu.Framework.Allocation;
 using osu.Framework.Graphics;
+using osu.Game.Resources.Localisation.Web;
 using osu.Game.Rulesets;
 
 namespace osu.Game.Overlays.BeatmapListing
@@ -10,7 +11,7 @@ namespace osu.Game.Overlays.BeatmapListing
     public class BeatmapSearchRulesetFilterRow : BeatmapSearchFilterRow<RulesetInfo>
     {
         public BeatmapSearchRulesetFilterRow()
-            : base(@"Mode")
+            : base(BeatmapsStrings.ListingSearchFiltersMode)
         {
         }
 

osu.Game/Overlays/BeatmapListing/BeatmapSearchScoreFilterRow.cs

@@ -4,6 +4,8 @@
 using System.Collections.Generic;
 using System.Linq;
 using osu.Framework.Extensions;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 using osu.Game.Scoring;
 
 namespace osu.Game.Overlays.BeatmapListing
@@ -11,7 +13,7 @@ namespace osu.Game.Overlays.BeatmapListing
     public class BeatmapSearchScoreFilterRow : BeatmapSearchMultipleSelectionFilterRow<ScoreRank>
     {
         public BeatmapSearchScoreFilterRow()
-            : base(@"Rank Achieved")
+            : base(BeatmapsStrings.ListingSearchFiltersRank)
         {
         }
 
@@ -31,20 +33,7 @@ namespace osu.Game.Overlays.BeatmapListing
             {
             }
 
-            protected override string LabelFor(ScoreRank value)
-            {
-                switch (value)
-                {
-                    case ScoreRank.XH:
-                        return @"Silver SS";
-
-                    case ScoreRank.SH:
-                        return @"Silver S";
-
-                    default:
-                        return value.GetDescription();
-                }
-            }
+            protected override LocalisableString LabelFor(ScoreRank value) => value.GetLocalisableDescription();
         }
     }
 }

osu.Game/Overlays/BeatmapListing/FilterTabItem.cs

@@ -7,6 +7,7 @@ using osu.Framework.Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.UserInterface;
 using osu.Framework.Input.Events;
+using osu.Framework.Localisation;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Graphics.UserInterface;
@@ -66,7 +67,7 @@ namespace osu.Game.Overlays.BeatmapListing
         /// <summary>
         /// Returns the label text to be used for the supplied <paramref name="value"/>.
         /// </summary>
-        protected virtual string LabelFor(T value) => (value as Enum)?.GetDescription() ?? value.ToString();
+        protected virtual LocalisableString LabelFor(T value) => (value as Enum)?.GetLocalisableDescription() ?? value.ToString();
 
         private void updateState()
         {

osu.Game/Overlays/BeatmapListing/SearchCategory.cs

@@ -1,10 +1,14 @@
 // 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.ComponentModel;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.BeatmapListing
 {
+    [LocalisableEnum(typeof(SearchCategoryEnumLocalisationMapper))]
     public enum SearchCategory
     {
         Any,
@@ -23,4 +27,43 @@ namespace osu.Game.Overlays.BeatmapListing
         [Description("My Maps")]
         Mine,
     }
+
+    public class SearchCategoryEnumLocalisationMapper : EnumLocalisationMapper<SearchCategory>
+    {
+        public override LocalisableString Map(SearchCategory value)
+        {
+            switch (value)
+            {
+                case SearchCategory.Any:
+                    return BeatmapsStrings.StatusAny;
+
+                case SearchCategory.Leaderboard:
+                    return BeatmapsStrings.StatusLeaderboard;
+
+                case SearchCategory.Ranked:
+                    return BeatmapsStrings.StatusRanked;
+
+                case SearchCategory.Qualified:
+                    return BeatmapsStrings.StatusQualified;
+
+                case SearchCategory.Loved:
+                    return BeatmapsStrings.StatusLoved;
+
+                case SearchCategory.Favourites:
+                    return BeatmapsStrings.StatusFavourites;
+
+                case SearchCategory.Pending:
+                    return BeatmapsStrings.StatusPending;
+
+                case SearchCategory.Graveyard:
+                    return BeatmapsStrings.StatusGraveyard;
+
+                case SearchCategory.Mine:
+                    return BeatmapsStrings.StatusMine;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value), value, null);
+            }
+        }
+    }
 }

osu.Game/Overlays/BeatmapListing/SearchExplicit.cs

@@ -1,11 +1,34 @@
 // 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 osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
+
 namespace osu.Game.Overlays.BeatmapListing
 {
+    [LocalisableEnum(typeof(SearchExplicitEnumLocalisationMapper))]
     public enum SearchExplicit
     {
         Hide,
         Show
     }
+
+    public class SearchExplicitEnumLocalisationMapper : EnumLocalisationMapper<SearchExplicit>
+    {
+        public override LocalisableString Map(SearchExplicit value)
+        {
+            switch (value)
+            {
+                case SearchExplicit.Hide:
+                    return BeatmapsStrings.NsfwExclude;
+
+                case SearchExplicit.Show:
+                    return BeatmapsStrings.NsfwInclude;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value), value, null);
+            }
+        }
+    }
 }

osu.Game/Overlays/BeatmapListing/SearchExtra.cs

@@ -1,10 +1,14 @@
 // 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.ComponentModel;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.BeatmapListing
 {
+    [LocalisableEnum(typeof(SearchExtraEnumLocalisationMapper))]
     public enum SearchExtra
     {
         [Description("Has Video")]
@@ -13,4 +17,22 @@ namespace osu.Game.Overlays.BeatmapListing
         [Description("Has Storyboard")]
         Storyboard
     }
+
+    public class SearchExtraEnumLocalisationMapper : EnumLocalisationMapper<SearchExtra>
+    {
+        public override LocalisableString Map(SearchExtra value)
+        {
+            switch (value)
+            {
+                case SearchExtra.Video:
+                    return BeatmapsStrings.ExtraVideo;
+
+                case SearchExtra.Storyboard:
+                    return BeatmapsStrings.ExtraStoryboard;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value), value, null);
+            }
+        }
+    }
 }

osu.Game/Overlays/BeatmapListing/SearchGeneral.cs

@@ -1,10 +1,14 @@
 // 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.ComponentModel;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.BeatmapListing
 {
+    [LocalisableEnum(typeof(SearchGeneralEnumLocalisationMapper))]
     public enum SearchGeneral
     {
         [Description("Recommended difficulty")]
@@ -16,4 +20,25 @@ namespace osu.Game.Overlays.BeatmapListing
         [Description("Subscribed mappers")]
         Follows
     }
+
+    public class SearchGeneralEnumLocalisationMapper : EnumLocalisationMapper<SearchGeneral>
+    {
+        public override LocalisableString Map(SearchGeneral value)
+        {
+            switch (value)
+            {
+                case SearchGeneral.Recommended:
+                    return BeatmapsStrings.GeneralRecommended;
+
+                case SearchGeneral.Converts:
+                    return BeatmapsStrings.GeneralConverts;
+
+                case SearchGeneral.Follows:
+                    return BeatmapsStrings.GeneralFollows;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value), value, null);
+            }
+        }
+    }
 }

osu.Game/Overlays/BeatmapListing/SearchGenre.cs

@@ -1,10 +1,14 @@
 // 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.ComponentModel;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.BeatmapListing
 {
+    [LocalisableEnum(typeof(SearchGenreEnumLocalisationMapper))]
     public enum SearchGenre
     {
         Any = 0,
@@ -26,4 +30,58 @@ namespace osu.Game.Overlays.BeatmapListing
         Folk = 13,
         Jazz = 14
     }
+
+    public class SearchGenreEnumLocalisationMapper : EnumLocalisationMapper<SearchGenre>
+    {
+        public override LocalisableString Map(SearchGenre value)
+        {
+            switch (value)
+            {
+                case SearchGenre.Any:
+                    return BeatmapsStrings.GenreAny;
+
+                case SearchGenre.Unspecified:
+                    return BeatmapsStrings.GenreUnspecified;
+
+                case SearchGenre.VideoGame:
+                    return BeatmapsStrings.GenreVideoGame;
+
+                case SearchGenre.Anime:
+                    return BeatmapsStrings.GenreAnime;
+
+                case SearchGenre.Rock:
+                    return BeatmapsStrings.GenreRock;
+
+                case SearchGenre.Pop:
+                    return BeatmapsStrings.GenrePop;
+
+                case SearchGenre.Other:
+                    return BeatmapsStrings.GenreOther;
+
+                case SearchGenre.Novelty:
+                    return BeatmapsStrings.GenreNovelty;
+
+                case SearchGenre.HipHop:
+                    return BeatmapsStrings.GenreHipHop;
+
+                case SearchGenre.Electronic:
+                    return BeatmapsStrings.GenreElectronic;
+
+                case SearchGenre.Metal:
+                    return BeatmapsStrings.GenreMetal;
+
+                case SearchGenre.Classical:
+                    return BeatmapsStrings.GenreClassical;
+
+                case SearchGenre.Folk:
+                    return BeatmapsStrings.GenreFolk;
+
+                case SearchGenre.Jazz:
+                    return BeatmapsStrings.GenreJazz;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value), value, null);
+            }
+        }
+    }
 }

osu.Game/Overlays/BeatmapListing/SearchLanguage.cs

@@ -1,10 +1,14 @@
 // 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 osu.Framework.Localisation;
 using osu.Framework.Utils;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays.BeatmapListing
 {
+    [LocalisableEnum(typeof(SearchLanguageEnumLocalisationMapper))]
     [HasOrderedElements]
     public enum SearchLanguage
     {
@@ -53,4 +57,61 @@ namespace osu.Game.Overlays.BeatmapListing
         [Order(13)]
         Other
     }
+
+    public class SearchLanguageEnumLocalisationMapper : EnumLocalisationMapper<SearchLanguage>
+    {
+        public override LocalisableString Map(SearchLanguage value)
+        {
+            switch (value)
+            {
+                case SearchLanguage.Any:
+                    return BeatmapsStrings.LanguageAny;
+
+                case SearchLanguage.Unspecified:
+                    return BeatmapsStrings.LanguageUnspecified;
+
+                case SearchLanguage.English:
+                    return BeatmapsStrings.LanguageEnglish;
+
+                case SearchLanguage.Japanese:
+                    return BeatmapsStrings.LanguageJapanese;
+
+                case SearchLanguage.Chinese:
+                    return BeatmapsStrings.LanguageChinese;
+
+                case SearchLanguage.Instrumental:
+                    return BeatmapsStrings.LanguageInstrumental;
+
+                case SearchLanguage.Korean:
+                    return BeatmapsStrings.LanguageKorean;
+
+                case SearchLanguage.French:
+                    return BeatmapsStrings.LanguageFrench;
+
+                case SearchLanguage.German:
+                    return BeatmapsStrings.LanguageGerman;
+
+                case SearchLanguage.Swedish:
+                    return BeatmapsStrings.LanguageSwedish;
+
+                case SearchLanguage.Spanish:
+                    return BeatmapsStrings.LanguageSpanish;
+
+                case SearchLanguage.Italian:
+                    return BeatmapsStrings.LanguageItalian;
+
+                case SearchLanguage.Russian:
+                    return BeatmapsStrings.LanguageRussian;
+
+                case SearchLanguage.Polish:
+                    return BeatmapsStrings.LanguagePolish;
+
+                case SearchLanguage.Other:
+                    return BeatmapsStrings.LanguageOther;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value), value, null);
+            }
+        }
+    }
 }

osu.Game/Overlays/BeatmapListing/SearchPlayed.cs

@@ -1,12 +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.
 
+using System;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
+
 namespace osu.Game.Overlays.BeatmapListing
 {
+    [LocalisableEnum(typeof(SearchPlayedEnumLocalisationMapper))]
     public enum SearchPlayed
     {
         Any,
         Played,
         Unplayed
     }
+
+    public class SearchPlayedEnumLocalisationMapper : EnumLocalisationMapper<SearchPlayed>
+    {
+        public override LocalisableString Map(SearchPlayed value)
+        {
+            switch (value)
+            {
+                case SearchPlayed.Any:
+                    return BeatmapsStrings.PlayedAny;
+
+                case SearchPlayed.Played:
+                    return BeatmapsStrings.PlayedPlayed;
+
+                case SearchPlayed.Unplayed:
+                    return BeatmapsStrings.PlayedUnplayed;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value), value, null);
+            }
+        }
+    }
 }

osu.Game/Overlays/BeatmapListing/SortCriteria.cs

@@ -1,8 +1,13 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using System;
+using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
+
 namespace osu.Game.Overlays.BeatmapListing
 {
+    [LocalisableEnum(typeof(SortCriteriaLocalisationMapper))]
     public enum SortCriteria
     {
         Title,
@@ -14,4 +19,40 @@ namespace osu.Game.Overlays.BeatmapListing
         Favourites,
         Relevance
     }
+
+    public class SortCriteriaLocalisationMapper : EnumLocalisationMapper<SortCriteria>
+    {
+        public override LocalisableString Map(SortCriteria value)
+        {
+            switch (value)
+            {
+                case SortCriteria.Title:
+                    return BeatmapsStrings.ListingSearchSortingTitle;
+
+                case SortCriteria.Artist:
+                    return BeatmapsStrings.ListingSearchSortingArtist;
+
+                case SortCriteria.Difficulty:
+                    return BeatmapsStrings.ListingSearchSortingDifficulty;
+
+                case SortCriteria.Ranked:
+                    return BeatmapsStrings.ListingSearchSortingRanked;
+
+                case SortCriteria.Rating:
+                    return BeatmapsStrings.ListingSearchSortingRating;
+
+                case SortCriteria.Plays:
+                    return BeatmapsStrings.ListingSearchSortingPlays;
+
+                case SortCriteria.Favourites:
+                    return BeatmapsStrings.ListingSearchSortingFavourites;
+
+                case SortCriteria.Relevance:
+                    return BeatmapsStrings.ListingSearchSortingRelevance;
+
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(value), value, null);
+            }
+        }
+    }
 }

osu.Game/Overlays/BeatmapListingOverlay.cs

@@ -18,6 +18,7 @@ using osu.Game.Beatmaps;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Overlays.BeatmapListing;
 using osu.Game.Overlays.BeatmapListing.Panels;
+using osu.Game.Resources.Localisation.Web;
 using osuTK;
 using osuTK.Graphics;
 
@@ -232,7 +233,7 @@ namespace osu.Game.Overlays
                         {
                             Anchor = Anchor.Centre,
                             Origin = Anchor.Centre,
-                            Text = @"... nope, nothing found.",
+                            Text = BeatmapsStrings.ListingSearchNotFoundQuote,
                         }
                     }
                 });

osu.Game/Overlays/BeatmapSet/AuthorInfo.cs

@@ -2,6 +2,7 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
+using osu.Framework.Allocation;
 using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
@@ -22,8 +23,8 @@ namespace osu.Game.Overlays.BeatmapSet
     {
         private const float height = 50;
 
-        private readonly UpdateableAvatar avatar;
-        private readonly FillFlowContainer fields;
+        private UpdateableAvatar avatar;
+        private FillFlowContainer fields;
 
         private BeatmapSetInfo beatmapSet;
 
@@ -35,11 +36,46 @@ namespace osu.Game.Overlays.BeatmapSet
                 if (value == beatmapSet) return;
 
                 beatmapSet = value;
-
-                updateDisplay();
+                Scheduler.AddOnce(updateDisplay);
             }
         }
 
+        [BackgroundDependencyLoader]
+        private void load()
+        {
+            RelativeSizeAxes = Axes.X;
+            Height = height;
+
+            Children = new Drawable[]
+            {
+                new Container
+                {
+                    AutoSizeAxes = Axes.Both,
+                    CornerRadius = 4,
+                    Masking = true,
+                    Child = avatar = new UpdateableAvatar(showGuestOnNull: false)
+                    {
+                        Size = new Vector2(height),
+                    },
+                    EdgeEffect = new EdgeEffectParameters
+                    {
+                        Colour = Color4.Black.Opacity(0.25f),
+                        Type = EdgeEffectType.Shadow,
+                        Radius = 4,
+                        Offset = new Vector2(0f, 1f),
+                    },
+                },
+                fields = new FillFlowContainer
+                {
+                    RelativeSizeAxes = Axes.Both,
+                    Direction = FillDirection.Vertical,
+                    Padding = new MarginPadding { Left = height + 5 },
+                },
+            };
+
+            Scheduler.AddOnce(updateDisplay);
+        }
+
         private void updateDisplay()
         {
             avatar.User = BeatmapSet?.Metadata.Author;
@@ -69,45 +105,6 @@ namespace osu.Game.Overlays.BeatmapSet
             }
         }
 
-        public AuthorInfo()
-        {
-            RelativeSizeAxes = Axes.X;
-            Height = height;
-
-            Children = new Drawable[]
-            {
-                new Container
-                {
-                    AutoSizeAxes = Axes.Both,
-                    CornerRadius = 4,
-                    Masking = true,
-                    Child = avatar = new UpdateableAvatar
-                    {
-                        ShowGuestOnNull = false,
-                        Size = new Vector2(height),
-                    },
-                    EdgeEffect = new EdgeEffectParameters
-                    {
-                        Colour = Color4.Black.Opacity(0.25f),
-                        Type = EdgeEffectType.Shadow,
-                        Radius = 4,
-                        Offset = new Vector2(0f, 1f),
-                    },
-                },
-                fields = new FillFlowContainer
-                {
-                    RelativeSizeAxes = Axes.Both,
-                    Direction = FillDirection.Vertical,
-                    Padding = new MarginPadding { Left = height + 5 },
-                },
-            };
-        }
-
-        private void load()
-        {
-            updateDisplay();
-        }
-
         private class Field : FillFlowContainer
         {
             public Field(string first, string second, FontUsage secondFont)

osu.Game/Overlays/BeatmapSet/Info.cs

@@ -36,7 +36,7 @@ namespace osu.Game.Overlays.BeatmapSet
         public Info()
         {
             MetadataSection source, tags, genre, language;
-            OsuSpriteText unrankedPlaceholder;
+            OsuSpriteText notRankedPlaceholder;
 
             RelativeSizeAxes = Axes.X;
             Height = base_height;
@@ -102,12 +102,12 @@ namespace osu.Game.Overlays.BeatmapSet
                                     RelativeSizeAxes = Axes.Both,
                                     Padding = new MarginPadding { Top = 20, Horizontal = 15 },
                                 },
-                                unrankedPlaceholder = new OsuSpriteText
+                                notRankedPlaceholder = new OsuSpriteText
                                 {
                                     Anchor = Anchor.Centre,
                                     Origin = Anchor.Centre,
                                     Alpha = 0,
-                                    Text = "Unranked beatmap",
+                                    Text = "This beatmap is not ranked",
                                     Font = OsuFont.GetFont(size: 12)
                                 },
                             },
@@ -124,7 +124,7 @@ namespace osu.Game.Overlays.BeatmapSet
                 language.Text = b.NewValue?.OnlineInfo?.Language?.Name ?? string.Empty;
                 var setHasLeaderboard = b.NewValue?.OnlineInfo?.Status > 0;
                 successRate.Alpha = setHasLeaderboard ? 1 : 0;
-                unrankedPlaceholder.Alpha = setHasLeaderboard ? 0 : 1;
+                notRankedPlaceholder.Alpha = setHasLeaderboard ? 0 : 1;
                 Height = setHasLeaderboard ? 270 : base_height;
             };
         }

osu.Game/Overlays/BeatmapSet/LeaderboardModSelector.cs

@@ -52,7 +52,7 @@ namespace osu.Game.Overlays.BeatmapSet
                 return;
 
             modsContainer.Add(new ModButton(new ModNoMod()));
-            modsContainer.AddRange(ruleset.NewValue.CreateInstance().GetAllMods().Where(m => m.Ranked).Select(m => new ModButton(m)));
+            modsContainer.AddRange(ruleset.NewValue.CreateInstance().GetAllMods().Where(m => m.UserPlayable).Select(m => new ModButton(m)));
 
             modsContainer.ForEach(button => button.OnSelectionChanged = selectionChanged);
         }

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

@@ -61,7 +61,7 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
                             },
                         }
                     },
-                    avatar = new UpdateableAvatar
+                    avatar = new UpdateableAvatar(showGuestOnNull: false)
                     {
                         Anchor = Anchor.Centre,
                         Origin = Anchor.Centre,
@@ -75,7 +75,6 @@ namespace osu.Game.Overlays.BeatmapSet.Scores
                             Offset = new Vector2(0, 2),
                             Radius = 1,
                         },
-                        ShowGuestOnNull = false,
                     },
                     new FillFlowContainer
                     {

osu.Game/Overlays/ChangelogOverlay.cs

@@ -8,7 +8,6 @@ using System.Threading.Tasks;
 using JetBrains.Annotations;
 using osu.Framework.Allocation;
 using osu.Framework.Audio;
-using osu.Framework.Audio.Sample;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
 using osu.Game.Input.Bindings;
@@ -25,8 +24,6 @@ namespace osu.Game.Overlays
 
         public readonly Bindable<APIChangelogBuild> Current = new Bindable<APIChangelogBuild>();
 
-        private Sample sampleBack;
-
         private List<APIChangelogBuild> builds;
 
         protected List<APIUpdateStream> Streams;
@@ -41,8 +38,6 @@ namespace osu.Game.Overlays
         {
             Header.Build.BindTarget = Current;
 
-            sampleBack = audio.Samples.Get(@"UI/generic-select-soft");
-
             Current.BindValueChanged(e =>
             {
                 if (e.NewValue != null)
@@ -108,7 +103,6 @@ namespace osu.Game.Overlays
                     else
                     {
                         Current.Value = null;
-                        sampleBack?.Play();
                     }
 
                     return true;

osu.Game/Overlays/Chat/DrawableChannel.cs

@@ -6,18 +6,18 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using osu.Framework.Allocation;
-using osuTK.Graphics;
+using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
-using osu.Game.Graphics.Containers;
-using osu.Game.Graphics.Cursor;
-using osu.Game.Online.Chat;
 using osu.Framework.Graphics.Shapes;
-using osu.Game.Graphics;
-using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics.Sprites;
 using osu.Framework.Utils;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+using osu.Game.Graphics.Cursor;
 using osu.Game.Graphics.Sprites;
+using osu.Game.Online.Chat;
+using osuTK.Graphics;
 
 namespace osu.Game.Overlays.Chat
 {

osu.Game/Overlays/Chat/Tabs/PrivateChannelTabItem.cs

@@ -51,7 +51,7 @@ namespace osu.Game.Overlays.Chat.Tabs
                             Child = new DelayedLoadWrapper(avatar = new ClickableAvatar(value.Users.First())
                             {
                                 RelativeSizeAxes = Axes.Both,
-                                OpenOnClick = { Value = false },
+                                OpenOnClick = false,
                             })
                             {
                                 RelativeSizeAxes = Axes.Both,

osu.Game/Overlays/OnlineOverlay.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Allocation;
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Game.Graphics.UserInterface;
@@ -13,7 +14,9 @@ namespace osu.Game.Overlays
     {
         protected override Container<Drawable> Content => content;
 
+        [Cached]
         protected readonly OverlayScrollContainer ScrollFlow;
+
         protected readonly LoadingLayer Loading;
         private readonly Container content;
 

osu.Game/Overlays/OverlaySortTabControl.cs

@@ -18,6 +18,7 @@ using JetBrains.Annotations;
 using System;
 using osu.Framework.Extensions;
 using osu.Framework.Localisation;
+using osu.Game.Resources.Localisation.Web;
 
 namespace osu.Game.Overlays
 {
@@ -54,7 +55,7 @@ namespace osu.Game.Overlays
                         Anchor = Anchor.CentreLeft,
                         Origin = Anchor.CentreLeft,
                         Font = OsuFont.GetFont(size: 12, weight: FontWeight.SemiBold),
-                        Text = @"Sort by"
+                        Text = SortStrings.Default
                     },
                     CreateControl().With(c =>
                     {
@@ -143,7 +144,7 @@ namespace osu.Game.Overlays
                             Anchor = Anchor.Centre,
                             Origin = Anchor.Centre,
                             Font = OsuFont.GetFont(size: 12, weight: FontWeight.SemiBold),
-                            Text = (value as Enum)?.GetDescription() ?? value.ToString()
+                            Text = (value as Enum)?.GetLocalisableDescription() ?? value.ToString()
                         }
                     }
                 });

osu.Game/Overlays/Profile/Header/TopHeaderContainer.cs

@@ -58,13 +58,11 @@ namespace osu.Game.Overlays.Profile.Header
                     Origin = Anchor.CentreLeft,
                     Children = new Drawable[]
                     {
-                        avatar = new UpdateableAvatar
+                        avatar = new UpdateableAvatar(openOnClick: false, showGuestOnNull: false)
                         {
                             Size = new Vector2(avatar_size),
                             Masking = true,
                             CornerRadius = avatar_size * 0.25f,
-                            OpenOnClick = { Value = false },
-                            ShowGuestOnNull = false,
                         },
                         new Container
                         {

osu.Game/Overlays/Settings/Sections/General/LanguageSettings.cs

@@ -1,11 +1,11 @@
 // 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 osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Configuration;
 using osu.Framework.Graphics;
+using osu.Game.Extensions;
 using osu.Game.Localisation;
 
 namespace osu.Game.Overlays.Settings.Sections.General
@@ -35,11 +35,11 @@ namespace osu.Game.Overlays.Settings.Sections.General
                 },
             };
 
-            if (!Enum.TryParse<Language>(frameworkLocale.Value, out var locale))
+            if (!LanguageExtensions.TryParseCultureCode(frameworkLocale.Value, out var locale))
                 locale = Language.en;
             languageSelection.Current.Value = locale;
 
-            languageSelection.Current.BindValueChanged(val => frameworkLocale.Value = val.NewValue.ToString());
+            languageSelection.Current.BindValueChanged(val => frameworkLocale.Value = val.NewValue.ToCultureCode());
         }
     }
 }

osu.Game/Overlays/Settings/Sections/Online/AlertsAndPrivacySettings.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.
+
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Game.Configuration;
+
+namespace osu.Game.Overlays.Settings.Sections.Online
+{
+    public class AlertsAndPrivacySettings : SettingsSubsection
+    {
+        protected override string Header => "Alerts and Privacy";
+
+        [BackgroundDependencyLoader]
+        private void load(OsuConfigManager config)
+        {
+            Children = new Drawable[]
+            {
+                new SettingsCheckbox
+                {
+                    LabelText = "Show a notification when someone mentions your name",
+                    Current = config.GetBindable<bool>(OsuSetting.NotifyOnUsernameMentioned)
+                },
+                new SettingsCheckbox
+                {
+                    LabelText = "Show a notification when you receive a private message",
+                    Current = config.GetBindable<bool>(OsuSetting.NotifyOnPrivateMessage)
+                },
+            };
+        }
+    }
+}

osu.Game/Overlays/Settings/Sections/OnlineSection.cs

@@ -21,6 +21,7 @@ namespace osu.Game.Overlays.Settings.Sections
             Children = new Drawable[]
             {
                 new WebSettings(),
+                new AlertsAndPrivacySettings(),
                 new IntegrationSettings()
             };
         }

osu.Game/Overlays/Settings/SettingsEnumDropdown.cs

@@ -19,6 +19,8 @@ namespace osu.Game.Overlays.Settings
                 Margin = new MarginPadding { Top = 5 };
                 RelativeSizeAxes = Axes.X;
             }
+
+            protected override DropdownMenu CreateMenu() => base.CreateMenu().With(m => m.MaxHeight = 200);
         }
     }
 }

osu.Game/Overlays/Settings/SettingsNumberBox.cs

@@ -2,16 +2,20 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using osu.Framework.Graphics;
-using osu.Game.Graphics.UserInterface;
 
 namespace osu.Game.Overlays.Settings
 {
     public class SettingsNumberBox : SettingsItem<string>
     {
-        protected override Drawable CreateControl() => new OsuNumberBox
+        protected override Drawable CreateControl() => new NumberBox
         {
             Margin = new MarginPadding { Top = 5 },
             RelativeSizeAxes = Axes.X,
         };
+
+        public class NumberBox : SettingsTextBox.TextBox
+        {
+            protected override bool CanAddCharacter(char character) => char.IsNumber(character);
+        }
     }
 }

osu.Game/Overlays/Settings/SettingsTextBox.cs

@@ -1,18 +1,60 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using osu.Framework.Allocation;
+using osu.Framework.Extensions.Color4Extensions;
 using osu.Framework.Graphics;
+using osu.Framework.Input.Events;
+using osu.Game.Graphics;
 using osu.Game.Graphics.UserInterface;
+using osuTK.Graphics;
 
 namespace osu.Game.Overlays.Settings
 {
     public class SettingsTextBox : SettingsItem<string>
     {
-        protected override Drawable CreateControl() => new OsuTextBox
+        protected override Drawable CreateControl() => new TextBox
         {
             Margin = new MarginPadding { Top = 5 },
             RelativeSizeAxes = Axes.X,
             CommitOnFocusLost = true,
         };
+
+        public class TextBox : OsuTextBox
+        {
+            private const float border_thickness = 3;
+
+            private Color4 borderColourFocused;
+            private Color4 borderColourUnfocused;
+
+            [BackgroundDependencyLoader]
+            private void load(OsuColour colour)
+            {
+                borderColourUnfocused = colour.Gray4.Opacity(0.5f);
+                borderColourFocused = BorderColour;
+
+                updateBorder();
+            }
+
+            protected override void OnFocus(FocusEvent e)
+            {
+                base.OnFocus(e);
+
+                updateBorder();
+            }
+
+            protected override void OnFocusLost(FocusLostEvent e)
+            {
+                base.OnFocusLost(e);
+
+                updateBorder();
+            }
+
+            private void updateBorder()
+            {
+                BorderThickness = border_thickness;
+                BorderColour = HasFocus ? borderColourFocused : borderColourUnfocused;
+            }
+        }
     }
 }

osu.Game/Overlays/TabControlOverlayHeader.cs

@@ -106,7 +106,19 @@ namespace osu.Game.Overlays
                 public OverlayHeaderTabItem(T value)
                     : base(value)
                 {
-                    Text.Text = ((Value as Enum)?.GetDescription() ?? Value.ToString()).ToLower();
+                    if (!(Value is Enum enumValue))
+                        Text.Text = Value.ToString().ToLower();
+                    else
+                    {
+                        var localisableDescription = enumValue.GetLocalisableDescription();
+                        var nonLocalisableDescription = enumValue.GetDescription();
+
+                        // If localisable == non-localisable, then we must have a basic string, so .ToLower() is used.
+                        Text.Text = localisableDescription.Equals(nonLocalisableDescription)
+                            ? nonLocalisableDescription.ToLower()
+                            : localisableDescription;
+                    }
+
                     Text.Font = OsuFont.GetFont(size: 14);
                     Text.Margin = new MarginPadding { Vertical = 16.5f }; // 15px padding + 1.5px line-height difference compensation
                     Bar.Margin = new MarginPadding { Bottom = bar_height };

osu.Game/Overlays/Toolbar/ToolbarUserButton.cs

@@ -32,14 +32,13 @@ namespace osu.Game.Overlays.Toolbar
 
             Add(new OpaqueBackground { Depth = 1 });
 
-            Flow.Add(avatar = new UpdateableAvatar
+            Flow.Add(avatar = new UpdateableAvatar(openOnClick: false)
             {
                 Masking = true,
                 Size = new Vector2(32),
                 Anchor = Anchor.CentreLeft,
                 Origin = Anchor.CentreLeft,
                 CornerRadius = 4,
-                OpenOnClick = { Value = false },
                 EdgeEffect = new EdgeEffectParameters
                 {
                     Type = EdgeEffectType.Shadow,

osu.Game/Overlays/Wiki/Markdown/WikiMarkdownContainer.cs

@@ -33,7 +33,7 @@ namespace osu.Game.Overlays.Wiki.Markdown
 
                 case ParagraphBlock paragraphBlock:
                     // Check if paragraph only contains an image
-                    if (paragraphBlock.Inline.Count() == 1 && paragraphBlock.Inline.FirstChild is LinkInline { IsImage: true } linkInline)
+                    if (paragraphBlock.Inline?.Count() == 1 && paragraphBlock.Inline.FirstChild is LinkInline { IsImage: true } linkInline)
                     {
                         container.Add(new WikiMarkdownImageBlock(linkInline));
                         return;

osu.Game/Overlays/Wiki/Markdown/WikiMarkdownImage.cs

@@ -2,19 +2,15 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using Markdig.Syntax.Inlines;
-using osu.Framework.Graphics.Containers.Markdown;
-using osu.Framework.Graphics.Cursor;
+using osu.Game.Graphics.Containers.Markdown;
 
 namespace osu.Game.Overlays.Wiki.Markdown
 {
-    public class WikiMarkdownImage : MarkdownImage, IHasTooltip
+    public class WikiMarkdownImage : OsuMarkdownImage
     {
-        public string TooltipText { get; }
-
         public WikiMarkdownImage(LinkInline linkInline)
-            : base(linkInline.Url)
+            : base(linkInline)
         {
-            TooltipText = linkInline.Title;
         }
 
         protected override ImageContainer CreateImageContainer(string url)

osu.Game/Overlays/Wiki/WikiArticlePage.cs

@@ -0,0 +1,80 @@
+// 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 Markdig.Syntax;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Containers.Markdown;
+using osu.Game.Overlays.Wiki.Markdown;
+
+namespace osu.Game.Overlays.Wiki
+{
+    public class WikiArticlePage : CompositeDrawable
+    {
+        public Container SidebarContainer { get; }
+
+        public WikiArticlePage(string currentPath, string markdown)
+        {
+            RelativeSizeAxes = Axes.X;
+            AutoSizeAxes = Axes.Y;
+
+            WikiSidebar sidebar;
+
+            InternalChild = new GridContainer
+            {
+                RelativeSizeAxes = Axes.X,
+                AutoSizeAxes = Axes.Y,
+                RowDimensions = new[]
+                {
+                    new Dimension(GridSizeMode.AutoSize),
+                },
+                ColumnDimensions = new[]
+                {
+                    new Dimension(GridSizeMode.AutoSize),
+                    new Dimension(),
+                },
+                Content = new[]
+                {
+                    new Drawable[]
+                    {
+                        SidebarContainer = new Container
+                        {
+                            AutoSizeAxes = Axes.X,
+                            Child = sidebar = new WikiSidebar(),
+                        },
+                        new ArticleMarkdownContainer
+                        {
+                            RelativeSizeAxes = Axes.X,
+                            AutoSizeAxes = Axes.Y,
+                            CurrentPath = currentPath,
+                            Text = markdown,
+                            DocumentMargin = new MarginPadding(0),
+                            DocumentPadding = new MarginPadding
+                            {
+                                Vertical = 20,
+                                Left = 30,
+                                Right = 50,
+                            },
+                            OnAddHeading = sidebar.AddEntry,
+                        }
+                    },
+                },
+            };
+        }
+
+        private class ArticleMarkdownContainer : WikiMarkdownContainer
+        {
+            public Action<HeadingBlock, MarkdownHeading> OnAddHeading;
+
+            protected override MarkdownHeading CreateHeading(HeadingBlock headingBlock)
+            {
+                var heading = base.CreateHeading(headingBlock);
+
+                OnAddHeading(headingBlock, heading);
+
+                return heading;
+            }
+        }
+    }
+}

osu.Game/Overlays/Wiki/WikiSidebar.cs

@@ -0,0 +1,66 @@
+// 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 Markdig.Syntax;
+using Markdig.Syntax.Inlines;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Containers.Markdown;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Sprites;
+
+namespace osu.Game.Overlays.Wiki
+{
+    public class WikiSidebar : OverlaySidebar
+    {
+        private WikiTableOfContents tableOfContents;
+
+        protected override Drawable CreateContent() => new FillFlowContainer
+        {
+            Direction = FillDirection.Vertical,
+            RelativeSizeAxes = Axes.X,
+            AutoSizeAxes = Axes.Y,
+            Children = new Drawable[]
+            {
+                new OsuSpriteText
+                {
+                    Text = "CONTENTS",
+                    Font = OsuFont.GetFont(size: 12, weight: FontWeight.Bold),
+                    Margin = new MarginPadding { Bottom = 5 },
+                },
+                tableOfContents = new WikiTableOfContents(),
+            },
+        };
+
+        public void AddEntry(HeadingBlock headingBlock, MarkdownHeading heading)
+        {
+            switch (headingBlock.Level)
+            {
+                case 2:
+                case 3:
+                    tableOfContents.AddEntry(getTitle(headingBlock.Inline), heading, headingBlock.Level == 3);
+                    break;
+            }
+        }
+
+        private string getTitle(ContainerInline containerInline)
+        {
+            foreach (var inline in containerInline)
+            {
+                switch (inline)
+                {
+                    case LiteralInline literalInline:
+                        return literalInline.Content.ToString();
+
+                    case LinkInline linkInline:
+                        if (!linkInline.IsImage)
+                            return getTitle(linkInline);
+
+                        break;
+                }
+            }
+
+            return string.Empty;
+        }
+    }
+}

osu.Game/Overlays/Wiki/WikiTableOfContents.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.
+
+using System.Collections.Generic;
+using osu.Framework.Allocation;
+using osu.Framework.Graphics;
+using osu.Framework.Graphics.Containers;
+using osu.Framework.Graphics.Containers.Markdown;
+using osu.Game.Graphics;
+using osu.Game.Graphics.Containers;
+
+namespace osu.Game.Overlays.Wiki
+{
+    public class WikiTableOfContents : CompositeDrawable
+    {
+        private readonly FillFlowContainer content;
+
+        private TableOfContentsEntry lastMainTitle;
+
+        private TableOfContentsEntry lastSubTitle;
+
+        public WikiTableOfContents()
+        {
+            RelativeSizeAxes = Axes.X;
+            AutoSizeAxes = Axes.Y;
+            InternalChild = content = new FillFlowContainer
+            {
+                Direction = FillDirection.Vertical,
+                RelativeSizeAxes = Axes.X,
+                AutoSizeAxes = Axes.Y,
+            };
+        }
+
+        public void AddEntry(string title, MarkdownHeading target, bool subtitle = false)
+        {
+            var entry = new TableOfContentsEntry(title, target, subtitle);
+
+            if (subtitle)
+            {
+                lastMainTitle.Margin = new MarginPadding(0);
+
+                if (lastSubTitle != null)
+                    lastSubTitle.Margin = new MarginPadding(0);
+
+                content.Add(lastSubTitle = entry.With(d => d.Margin = new MarginPadding { Bottom = 10 }));
+
+                return;
+            }
+
+            lastSubTitle = null;
+
+            content.Add(lastMainTitle = entry.With(d => d.Margin = new MarginPadding { Bottom = 5 }));
+        }
+
+        private class TableOfContentsEntry : OsuHoverContainer
+        {
+            private readonly MarkdownHeading target;
+
+            private readonly OsuTextFlowContainer textFlow;
+
+            public TableOfContentsEntry(string text, MarkdownHeading target, bool subtitle = false)
+            {
+                this.target = target;
+
+                RelativeSizeAxes = Axes.X;
+                AutoSizeAxes = Axes.Y;
+                Child = textFlow = new OsuTextFlowContainer(t =>
+                {
+                    t.Font = OsuFont.GetFont(size: subtitle ? 12 : 15);
+                }).With(f =>
+                {
+                    f.AddText(text);
+                    f.RelativeSizeAxes = Axes.X;
+                    f.AutoSizeAxes = Axes.Y;
+                    f.Margin = new MarginPadding { Bottom = 2 };
+                });
+                Padding = new MarginPadding { Left = subtitle ? 10 : 0 };
+            }
+
+            protected override IEnumerable<Drawable> EffectTargets => new Drawable[] { textFlow };
+
+            [BackgroundDependencyLoader]
+            private void load(OverlayColourProvider colourProvider, OverlayScrollContainer scrollContainer)
+            {
+                IdleColour = colourProvider.Light2;
+                HoverColour = colourProvider.Light1;
+                Action = () => scrollContainer.ScrollTo(target);
+            }
+        }
+    }
+}

osu.Game/Overlays/WikiOverlay.cs

@@ -1,6 +1,7 @@
 // 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 System.Threading;
 using osu.Framework.Allocation;
@@ -10,7 +11,6 @@ using osu.Game.Online.API;
 using osu.Game.Online.API.Requests;
 using osu.Game.Online.API.Requests.Responses;
 using osu.Game.Overlays.Wiki;
-using osu.Game.Overlays.Wiki.Markdown;
 
 namespace osu.Game.Overlays
 {
@@ -31,6 +31,8 @@ namespace osu.Game.Overlays
 
         private bool displayUpdateRequired = true;
 
+        private WikiArticlePage articlePage;
+
         public WikiOverlay()
             : base(OverlayColourScheme.Orange, false)
         {
@@ -82,6 +84,17 @@ namespace osu.Game.Overlays
             }, (cancellationToken = new CancellationTokenSource()).Token);
         }
 
+        protected override void UpdateAfterChildren()
+        {
+            base.UpdateAfterChildren();
+
+            if (articlePage != null)
+            {
+                articlePage.SidebarContainer.Height = DrawHeight;
+                articlePage.SidebarContainer.Y = Math.Clamp(ScrollFlow.Current - Header.DrawHeight, 0, Math.Max(ScrollFlow.ScrollContent.DrawHeight - DrawHeight - Header.DrawHeight, 0));
+            }
+        }
+
         private void onPathChanged(ValueChangedEvent<string> e)
         {
             cancellationToken?.Cancel();
@@ -115,39 +128,14 @@ namespace osu.Game.Overlays
             }
             else
             {
-                LoadDisplay(new WikiMarkdownContainer
-                {
-                    RelativeSizeAxes = Axes.X,
-                    AutoSizeAxes = Axes.Y,
-                    CurrentPath = $@"{api.WebsiteRootUrl}/wiki/{path.Value}/",
-                    Text = response.Markdown,
-                    DocumentMargin = new MarginPadding(0),
-                    DocumentPadding = new MarginPadding
-                    {
-                        Vertical = 20,
-                        Left = 30,
-                        Right = 50,
-                    },
-                });
+                LoadDisplay(articlePage = new WikiArticlePage($@"{api.WebsiteRootUrl}/wiki/{path.Value}/", response.Markdown));
             }
         }
 
         private void onFail()
         {
-            LoadDisplay(new WikiMarkdownContainer
-            {
-                RelativeSizeAxes = Axes.X,
-                AutoSizeAxes = Axes.Y,
-                CurrentPath = $@"{api.WebsiteRootUrl}/wiki/",
-                Text = $"Something went wrong when trying to fetch page \"{path.Value}\".\n\n[Return to the main page](Main_Page).",
-                DocumentMargin = new MarginPadding(0),
-                DocumentPadding = new MarginPadding
-                {
-                    Vertical = 20,
-                    Left = 30,
-                    Right = 50,
-                },
-            });
+            LoadDisplay(articlePage = new WikiArticlePage($@"{api.WebsiteRootUrl}/wiki/",
+                $"Something went wrong when trying to fetch page \"{path.Value}\".\n\n[Return to the main page](Main_Page)."));
         }
 
         private void showParentPage()

osu.Game/Performance/HighPerformanceSession.cs

@@ -0,0 +1,47 @@
+// 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.Runtime;
+using osu.Framework.Allocation;
+using osu.Framework.Bindables;
+using osu.Framework.Graphics;
+
+namespace osu.Game.Performance
+{
+    public class HighPerformanceSession : Component
+    {
+        private readonly IBindable<bool> localUserPlaying = new Bindable<bool>();
+        private GCLatencyMode originalGCMode;
+
+        [BackgroundDependencyLoader]
+        private void load(OsuGame game)
+        {
+            localUserPlaying.BindTo(game.LocalUserPlaying);
+        }
+
+        protected override void LoadComplete()
+        {
+            base.LoadComplete();
+
+            localUserPlaying.BindValueChanged(playing =>
+            {
+                if (playing.NewValue)
+                    EnableHighPerformanceSession();
+                else
+                    DisableHighPerformanceSession();
+            }, true);
+        }
+
+        protected virtual void EnableHighPerformanceSession()
+        {
+            originalGCMode = GCSettings.LatencyMode;
+            GCSettings.LatencyMode = GCLatencyMode.LowLatency;
+        }
+
+        protected virtual void DisableHighPerformanceSession()
+        {
+            if (GCSettings.LatencyMode == GCLatencyMode.LowLatency)
+                GCSettings.LatencyMode = originalGCMode;
+        }
+    }
+}

osu.Game/Rulesets/Difficulty/DifficultyAttributes.cs

@@ -8,11 +8,11 @@ namespace osu.Game.Rulesets.Difficulty
 {
     public class DifficultyAttributes
     {
-        public Mod[] Mods;
-        public Skill[] Skills;
+        public Mod[] Mods { get; set; }
+        public Skill[] Skills { get; set; }
 
-        public double StarRating;
-        public int MaxCombo;
+        public double StarRating { get; set; }
+        public int MaxCombo { get; set; }
 
         public DifficultyAttributes()
         {

osu.Game/Rulesets/Edit/HitObjectComposer.cs

@@ -43,6 +43,9 @@ namespace osu.Game.Rulesets.Edit
 
         protected readonly Ruleset Ruleset;
 
+        // Provides `Playfield`
+        private DependencyContainer dependencies;
+
         [Resolved]
         protected EditorClock EditorClock { get; private set; }
 
@@ -69,6 +72,9 @@ namespace osu.Game.Rulesets.Edit
             Ruleset = ruleset;
         }
 
+        protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent) =>
+            dependencies = new DependencyContainer(base.CreateChildDependencies(parent));
+
         [BackgroundDependencyLoader]
         private void load()
         {
@@ -88,6 +94,8 @@ namespace osu.Game.Rulesets.Edit
                 return;
             }
 
+            dependencies.CacheAs(Playfield);
+
             const float toolbar_width = 200;
 
             InternalChildren = new Drawable[]

osu.Game/Rulesets/Judgements/DrawableJudgement.cs

@@ -1,7 +1,6 @@
 // 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.Diagnostics;
 using JetBrains.Annotations;
 using osu.Framework.Allocation;
@@ -32,18 +31,6 @@ namespace osu.Game.Rulesets.Judgements
 
         private readonly Container aboveHitObjectsContent;
 
-        /// <summary>
-        /// Duration of initial fade in.
-        /// </summary>
-        [Obsolete("Apply any animations manually via ApplyHitAnimations / ApplyMissAnimations. Defaults were moved inside skinned components.")]
-        protected virtual double FadeInDuration => 100;
-
-        /// <summary>
-        /// Duration to wait until fade out begins. Defaults to <see cref="FadeInDuration"/>.
-        /// </summary>
-        [Obsolete("Apply any animations manually via ApplyHitAnimations / ApplyMissAnimations. Defaults were moved inside skinned components.")]
-        protected virtual double FadeOutDelay => FadeInDuration;
-
         /// <summary>
         /// Creates a drawable which visualises a <see cref="Judgements.Judgement"/>.
         /// </summary>

osu.Game/Rulesets/Judgements/Judgement.cs

@@ -1,7 +1,6 @@
 // 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 osu.Game.Rulesets.Objects;
 using osu.Game.Rulesets.Scoring;
 
@@ -69,14 +68,6 @@ namespace osu.Game.Rulesets.Judgements
         /// </summary>
         public double MaxHealthIncrease => HealthIncreaseFor(MaxResult);
 
-        /// <summary>
-        /// Retrieves the numeric score representation of a <see cref="HitResult"/>.
-        /// </summary>
-        /// <param name="result">The <see cref="HitResult"/> to find the numeric score representation for.</param>
-        /// <returns>The numeric score representation of <paramref name="result"/>.</returns>
-        [Obsolete("Has no effect. Use ToNumericResult(HitResult) (standardised across all rulesets).")] // Can be made non-virtual 20210328
-        protected virtual int NumericResultFor(HitResult result) => ToNumericResult(result);
-
         /// <summary>
         /// Retrieves the numeric score representation of a <see cref="JudgementResult"/>.
         /// </summary>

osu.Game/Rulesets/Mods/IApplicableToDrawableHitObject.cs

@@ -1,7 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System.Collections.Generic;
 using osu.Game.Rulesets.Objects.Drawables;
 
 namespace osu.Game.Rulesets.Mods
@@ -9,13 +8,12 @@ namespace osu.Game.Rulesets.Mods
     /// <summary>
     /// An interface for <see cref="Mod"/>s that can be applied to <see cref="DrawableHitObject"/>s.
     /// </summary>
-    public interface IApplicableToDrawableHitObjects : IApplicableMod
+    public interface IApplicableToDrawableHitObject : IApplicableMod
     {
         /// <summary>
-        /// Applies this <see cref="IApplicableToDrawableHitObjects"/> to a list of <see cref="DrawableHitObject"/>s.
+        /// Applies this <see cref="IApplicableToDrawableHitObject"/> to a <see cref="DrawableHitObject"/>.
         /// This will only be invoked with top-level <see cref="DrawableHitObject"/>s. Access <see cref="DrawableHitObject.NestedHitObjects"/> if adjusting nested objects is necessary.
         /// </summary>
-        /// <param name="drawables">The list of <see cref="DrawableHitObject"/>s to apply to.</param>
-        void ApplyToDrawableHitObjects(IEnumerable<DrawableHitObject> drawables);
+        void ApplyToDrawableHitObject(DrawableHitObject drawable);
     }
 }

osu.Game/Rulesets/Mods/IApplicableToDrawableHitObjects.cs

@@ -0,0 +1,18 @@
+// 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 osu.Framework.Extensions.IEnumerableExtensions;
+using osu.Game.Rulesets.Objects.Drawables;
+
+namespace osu.Game.Rulesets.Mods
+{
+    [Obsolete(@"Use the singular version IApplicableToDrawableHitObject instead.")] // Can be removed 20211216
+    public interface IApplicableToDrawableHitObjects : IApplicableToDrawableHitObject
+    {
+        void ApplyToDrawableHitObjects(IEnumerable<DrawableHitObject> drawables);
+
+        void IApplicableToDrawableHitObject.ApplyToDrawableHitObject(DrawableHitObject drawable) => ApplyToDrawableHitObjects(drawable.Yield());
+    }
+}

osu.Game/Rulesets/Mods/Mod.cs

@@ -108,10 +108,14 @@ namespace osu.Game.Rulesets.Mods
         public virtual bool HasImplementation => this is IApplicableMod;
 
         /// <summary>
-        /// Returns if this mod is ranked.
+        /// Whether this mod is playable by an end user.
+        /// Should be <c>false</c> for cases where the user is not interacting with the game (so it can be excluded from mutliplayer selection, for example).
         /// </summary>
         [JsonIgnore]
-        public virtual bool Ranked => false;
+        public virtual bool UserPlayable => true;
+
+        [Obsolete("Going forward, the concept of \"ranked\" doesn't exist. The only exceptions are automation mods, which should now override and set UserPlayable to true.")] // Can be removed 20211009
+        public virtual bool IsRanked => false;
 
         /// <summary>
         /// Whether this mod requires configuration to apply changes to the game.

osu.Game/Rulesets/Mods/ModAutoplay.cs

@@ -24,6 +24,8 @@ namespace osu.Game.Rulesets.Mods
 
         public bool RestartOnFail => false;
 
+        public override bool UserPlayable => false;
+
         public override Type[] IncompatibleMods => new[] { typeof(ModRelax), typeof(ModFailCondition), typeof(ModNoFail) };
 
         public override bool HasImplementation => GetType().GenericTypeArguments.Length == 0;

osu.Game/Rulesets/Mods/ModClassic.cs

@@ -17,8 +17,6 @@ namespace osu.Game.Rulesets.Mods
 
         public override string Description => "Feeling nostalgic?";
 
-        public override bool Ranked => false;
-
         public override ModType Type => ModType.Conversion;
     }
 }

osu.Game/Rulesets/Mods/ModDoubleTime.cs

@@ -17,7 +17,6 @@ namespace osu.Game.Rulesets.Mods
         public override IconUsage? Icon => OsuIcon.ModDoubletime;
         public override ModType Type => ModType.DifficultyIncrease;
         public override string Description => "Zoooooooooom...";
-        public override bool Ranked => true;
 
         public override Type[] IncompatibleMods => base.IncompatibleMods.Append(typeof(ModHalfTime)).ToArray();
 

osu.Game/Rulesets/Mods/ModEasy.cs

@@ -15,7 +15,6 @@ namespace osu.Game.Rulesets.Mods
         public override IconUsage? Icon => OsuIcon.ModEasy;
         public override ModType Type => ModType.DifficultyReduction;
         public override double ScoreMultiplier => 0.5;
-        public override bool Ranked => true;
         public override Type[] IncompatibleMods => new[] { typeof(ModHardRock), typeof(ModDifficultyAdjust) };
 
         public virtual void ReadFromDifficulty(BeatmapDifficulty difficulty)

osu.Game/Rulesets/Mods/ModFlashlight.cs

@@ -31,7 +31,6 @@ namespace osu.Game.Rulesets.Mods
         public override IconUsage? Icon => OsuIcon.ModFlashlight;
         public override ModType Type => ModType.DifficultyIncrease;
         public override string Description => "Restricted view area.";
-        public override bool Ranked => true;
 
         internal ModFlashlight()
         {

osu.Game/Rulesets/Mods/ModHalfTime.cs

@@ -17,7 +17,6 @@ namespace osu.Game.Rulesets.Mods
         public override IconUsage? Icon => OsuIcon.ModHalftime;
         public override ModType Type => ModType.DifficultyReduction;
         public override string Description => "Less zoom...";
-        public override bool Ranked => true;
 
         public override Type[] IncompatibleMods => base.IncompatibleMods.Append(typeof(ModDoubleTime)).ToArray();
 

osu.Game/Rulesets/Mods/ModHidden.cs

@@ -14,7 +14,6 @@ namespace osu.Game.Rulesets.Mods
         public override string Acronym => "HD";
         public override IconUsage? Icon => OsuIcon.ModHidden;
         public override ModType Type => ModType.DifficultyIncrease;
-        public override bool Ranked => true;
 
         public void ApplyToScoreProcessor(ScoreProcessor scoreProcessor)
         {

osu.Game/Rulesets/Mods/ModNoFail.cs

@@ -15,7 +15,6 @@ namespace osu.Game.Rulesets.Mods
         public override ModType Type => ModType.DifficultyReduction;
         public override string Description => "You can't fail, no matter what.";
         public override double ScoreMultiplier => 0.5;
-        public override bool Ranked => true;
         public override Type[] IncompatibleMods => new[] { typeof(ModRelax), typeof(ModFailCondition), typeof(ModAutoplay) };
     }
 }

osu.Game/Rulesets/Mods/ModPerfect.cs

@@ -16,7 +16,6 @@ namespace osu.Game.Rulesets.Mods
         public override string Acronym => "PF";
         public override IconUsage? Icon => OsuIcon.ModPerfect;
         public override ModType Type => ModType.DifficultyIncrease;
-        public override bool Ranked => true;
         public override double ScoreMultiplier => 1;
         public override string Description => "SS or quit.";
 

osu.Game/Rulesets/Mods/ModRandom.cs

@@ -8,7 +8,6 @@ using osu.Framework.Graphics.Sprites;
 using osu.Framework.Graphics.UserInterface;
 using osu.Game.Configuration;
 using osu.Game.Graphics;
-using osu.Game.Graphics.UserInterface;
 using osu.Game.Overlays.Settings;
 
 namespace osu.Game.Rulesets.Mods
@@ -50,7 +49,7 @@ namespace osu.Game.Rulesets.Mods
                     }
                 }
 
-                private readonly OsuNumberBox seedNumberBox;
+                private readonly SettingsNumberBox.NumberBox seedNumberBox;
 
                 public SeedControl()
                 {
@@ -76,7 +75,7 @@ namespace osu.Game.Rulesets.Mods
                             {
                                 new Drawable[]
                                 {
-                                    seedNumberBox = new OsuNumberBox
+                                    seedNumberBox = new SettingsNumberBox.NumberBox
                                     {
                                         RelativeSizeAxes = Axes.X,
                                         CommitOnFocusLost = true