Add client/server models & operations for "daily challenge" feature

osu.Game/Online/Metadata/DailyChallengeInfo.cs

@@ -0,0 +1,16 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using MessagePack;
+
+namespace osu.Game.Online.Metadata
+{
+    [MessagePackObject]
+    [Serializable]
+    public struct DailyChallengeInfo
+    {
+        [Key(0)]
+        public long RoomID { get; set; }
+    }
+}

osu.Game/Online/Metadata/IMetadataClient.cs

@@ -20,5 +20,11 @@ namespace osu.Game.Online.Metadata
         /// Delivers an update of the <see cref="UserPresence"/> of the user with the supplied <paramref name="userId"/>.
         /// </summary>
         Task UserPresenceUpdated(int userId, UserPresence? status);
+
+        /// <summary>
+        /// Delivers an update of the current "daily challenge" status.
+        /// Null value means there is no "daily challenge" currently active.
+        /// </summary>
+        Task DailyChallengeUpdated(DailyChallengeInfo? info);
     }
 }

osu.Game/Online/Metadata/IMetadataServer.cs

@@ -7,7 +7,12 @@ using osu.Game.Users;
 namespace osu.Game.Online.Metadata
 {
     /// <summary>
-    /// Metadata server is responsible for keeping the osu! client up-to-date with any changes.
+    /// Metadata server is responsible for keeping the osu! client up-to-date with various real-time happenings, such as:
+    /// <list type="bullet">
+    /// <item>beatmap updates via BSS,</item>
+    /// <item>online user activity/status updates,</item>
+    /// <item>other real-time happenings, such as current "daily challenge" status.</item>
+    /// </list>
     /// </summary>
     public interface IMetadataServer
     {

osu.Game/Online/Metadata/MetadataClient.cs

@@ -59,6 +59,15 @@ namespace osu.Game.Online.Metadata
 
         #endregion
 
+        #region Daily Challenge
+
+        public abstract IBindable<DailyChallengeInfo?> DailyChallengeInfo { get; }
+
+        /// <inheritdoc/>
+        public abstract Task DailyChallengeUpdated(DailyChallengeInfo? info);
+
+        #endregion
+
         #region Disconnection handling
 
         public event Action? Disconnecting;

osu.Game/Online/Metadata/OnlineMetadataClient.cs

@@ -26,6 +26,9 @@ namespace osu.Game.Online.Metadata
         public override IBindableDictionary<int, UserPresence> UserStates => userStates;
         private readonly BindableDictionary<int, UserPresence> userStates = new BindableDictionary<int, UserPresence>();
 
+        public override IBindable<DailyChallengeInfo?> DailyChallengeInfo => dailyChallengeInfo;
+        private readonly Bindable<DailyChallengeInfo?> dailyChallengeInfo = new Bindable<DailyChallengeInfo?>();
+
         private readonly string endpoint;
 
         private IHubClientConnector? connector;
@@ -58,6 +61,7 @@ namespace osu.Game.Online.Metadata
                     // https://github.com/dotnet/aspnetcore/issues/15198
                     connection.On<BeatmapUpdates>(nameof(IMetadataClient.BeatmapSetsUpdated), ((IMetadataClient)this).BeatmapSetsUpdated);
                     connection.On<int, UserPresence?>(nameof(IMetadataClient.UserPresenceUpdated), ((IMetadataClient)this).UserPresenceUpdated);
+                    connection.On<DailyChallengeInfo?>(nameof(IMetadataClient.DailyChallengeUpdated), ((IMetadataClient)this).DailyChallengeUpdated);
                     connection.On(nameof(IStatefulUserHubClient.DisconnectRequested), ((IMetadataClient)this).DisconnectRequested);
                 };
 
@@ -101,6 +105,7 @@ namespace osu.Game.Online.Metadata
                 {
                     isWatchingUserPresence.Value = false;
                     userStates.Clear();
+                    dailyChallengeInfo.Value = null;
                 });
                 return;
             }
@@ -229,6 +234,12 @@ namespace osu.Game.Online.Metadata
             }
         }
 
+        public override Task DailyChallengeUpdated(DailyChallengeInfo? info)
+        {
+            Schedule(() => dailyChallengeInfo.Value = info);
+            return Task.CompletedTask;
+        }
+
         public override async Task DisconnectRequested()
         {
             await base.DisconnectRequested().ConfigureAwait(false);

osu.Game/Online/Rooms/RoomCategory.cs

@@ -13,5 +13,8 @@ namespace osu.Game.Online.Rooms
 
         [Description("Featured Artist")]
         FeaturedArtist,
+
+        [Description("Daily Challenge")]
+        DailyChallenge,
     }
 }

osu.Game/Tests/Visual/Metadata/TestMetadataClient.cs

@@ -21,6 +21,9 @@ namespace osu.Game.Tests.Visual.Metadata
         public override IBindableDictionary<int, UserPresence> UserStates => userStates;
         private readonly BindableDictionary<int, UserPresence> userStates = new BindableDictionary<int, UserPresence>();
 
+        public override IBindable<DailyChallengeInfo?> DailyChallengeInfo => dailyChallengeInfo;
+        private readonly Bindable<DailyChallengeInfo?> dailyChallengeInfo = new Bindable<DailyChallengeInfo?>();
+
         [Resolved]
         private IAPIProvider api { get; set; } = null!;
 
@@ -77,5 +80,11 @@ namespace osu.Game.Tests.Visual.Metadata
             => Task.FromResult(new BeatmapUpdates(Array.Empty<int>(), queueId));
 
         public override Task BeatmapSetsUpdated(BeatmapUpdates updates) => Task.CompletedTask;
+
+        public override Task DailyChallengeUpdated(DailyChallengeInfo? info)
+        {
+            dailyChallengeInfo.Value = info;
+            return Task.CompletedTask;
+        }
     }
 }