Add change ingester to handle passing of online changes to correct target components

osu.Game/Beatmaps/BeatmapOnlineChangeIngest.cs

@@ -0,0 +1,52 @@
+// 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 osu.Framework.Graphics;
+using osu.Game.Database;
+using osu.Game.Online.Metadata;
+
+namespace osu.Game.Beatmaps
+{
+    /// <summary>
+    /// Ingests any changes that happen externally to the client, reprocessing as required.
+    /// </summary>
+    public class BeatmapOnlineChangeIngest : Component
+    {
+        private readonly BeatmapUpdater beatmapUpdater;
+        private readonly RealmAccess realm;
+        private readonly MetadataClient metadataClient;
+
+        public BeatmapOnlineChangeIngest(BeatmapUpdater beatmapUpdater, RealmAccess realm, MetadataClient metadataClient)
+        {
+            this.beatmapUpdater = beatmapUpdater;
+            this.realm = realm;
+            this.metadataClient = metadataClient;
+
+            metadataClient.ChangedBeatmapSetsArrived += changesDetected;
+        }
+
+        private void changesDetected(int[] beatmapSetIds)
+        {
+            // May want to batch incoming updates further if the background realm operations ever becomes a concern.
+            realm.Run(r =>
+            {
+                foreach (int id in beatmapSetIds)
+                {
+                    var matchingSet = r.All<BeatmapSetInfo>().FirstOrDefault(s => s.OnlineID == id);
+
+                    if (matchingSet != null)
+                        beatmapUpdater.Queue(matchingSet.ToLive(realm));
+                }
+            });
+        }
+
+        protected override void Dispose(bool isDisposing)
+        {
+            base.Dispose(isDisposing);
+            metadataClient.ChangedBeatmapSetsArrived -= changesDetected;
+        }
+    }
+}