Source Code added

mobile/lib/providers/activity_statistics.provider.dart

@@ -0,0 +1,22 @@
+import 'package:immich_mobile/providers/activity_service.provider.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'activity_statistics.provider.g.dart';
+
+// ignore: unintended_html_in_doc_comment
+/// Maintains the current number of comments by <shared-album, asset>
+@riverpod
+class ActivityStatistics extends _$ActivityStatistics {
+  @override
+  int build(String albumId, [String? assetId]) {
+    ref.watch(activityServiceProvider).getStatistics(albumId, assetId: assetId).then((stats) => state = stats.comments);
+    return 0;
+  }
+
+  void addActivity() => state = state + 1;
+
+  void removeActivity() => state = state - 1;
+}
+
+/// Mock class for testing
+abstract class ActivityStatisticsInternal extends _$ActivityStatistics {}