feat: import Chinese-localized Buzz source snapshot

Signed-off-by: cls_宁波本机 <908705107@qq.com>

mobile/lib/features/channels/unread_badge/unread_badge_provider.dart

@@ -0,0 +1,87 @@
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../channels_provider.dart';
+import '../../../shared/read_state/read_state_provider.dart';
+import '../../../shared/read_state/read_state_format.dart';
+import 'observed_unread_event.dart';
+
+class UnreadBadgeState {
+  const UnreadBadgeState({
+    this.highPriorityCount = 0,
+    this.generalUnreadCount = 0,
+  });
+
+  final int highPriorityCount;
+  final int generalUnreadCount;
+}
+
+final unreadBadgeProvider = Provider<UnreadBadgeState>((ref) {
+  final channelsAsync = ref.watch(channelsProvider);
+  final readState = ref.watch(readStateProvider);
+
+  return channelsAsync.when(
+    data: (channels) {
+      final notifier = ref.read(channelsProvider.notifier);
+      final observedEventsByChannel = notifier.observedUnreadEventsByChannel;
+      final latestObservedByChannel = notifier.latestObservedByChannel;
+
+      var highPriority = 0;
+      var general = 0;
+
+      for (final channel in channels) {
+        if (!channel.isMember || channel.isArchived) continue;
+
+        if (readState.locallyForcedChannelIds.contains(channel.id)) {
+          general++;
+          continue;
+        }
+
+        if (!latestObservedByChannel.containsKey(channel.id)) continue;
+
+        final observedEvents = observedEventsByChannel[channel.id];
+        final channelReadAt = readState.effectiveTimestamp(channel.id);
+        int? readAtForObservedEvent(ObservedUnreadEvent event) =>
+            observedUnreadEventReadAt(
+              event,
+              channelReadAt,
+              (rootId) =>
+                  readState.effectiveTimestamp(threadContextKey(rootId)),
+              (messageId) =>
+                  readState.effectiveTimestamp(msgContextKey(messageId)),
+            );
+
+        final unreadCount = countUnreadObservedEvents(
+          observedEvents,
+          readAtForObservedEvent,
+        );
+        if (unreadCount == 0) continue;
+
+        if (channel.isDm ||
+            countUnreadHighPriorityObservedEvents(
+                  observedEvents,
+                  readAtForObservedEvent,
+                ) >
+                0) {
+          final appBadgeCount = countUnreadAppBadgeObservedEvents(
+            observedEvents,
+            readAtForObservedEvent,
+          );
+          highPriority += appBadgeCount > 0 ? appBadgeCount : 1;
+        } else {
+          final badgeCount = countUnreadBadgeObservedEvents(
+            observedEvents,
+            readAtForObservedEvent,
+          );
+          general += badgeCount > 0 ? badgeCount : 1;
+        }
+      }
+
+      return UnreadBadgeState(
+        highPriorityCount: highPriority,
+        generalUnreadCount: general,
+      );
+    },
+    loading: () => const UnreadBadgeState(),
+    error: (_, _) => const UnreadBadgeState(),
+  );
+});