feat: import Chinese-localized Buzz source snapshot

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

mobile/lib/features/forum/forum_provider.dart

@@ -0,0 +1,189 @@
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../../shared/relay/relay.dart';
+import '../channels/channel_management_provider.dart';
+import '../../shared/custom_emoji/custom_emoji.dart';
+import '../../shared/custom_emoji/custom_emoji_provider.dart';
+import 'forum_models.dart';
+
+/// Fetches forum posts (kind:45001) for a channel from the relay.
+///
+/// Posts are top-level events tagged `#h:<channelId>`. Invalidate to refresh
+/// (e.g. after creating a new post).
+final forumPostsProvider = FutureProvider.family<ForumPostsResponse, String>((
+  ref,
+  channelId,
+) async {
+  final session = ref.watch(relaySessionProvider.notifier);
+  final events = await session.fetchHistory(
+    NostrFilters.forumPosts(channelId, limit: 50),
+  );
+  return ForumPostsResponse.fromEvents(events);
+});
+
+/// Fetches a forum thread (root post + replies) from the relay.
+final forumThreadProvider =
+    FutureProvider.family<
+      ForumThreadResponse,
+      ({String channelId, String eventId})
+    >((ref, args) async {
+      final session = ref.watch(relaySessionProvider.notifier);
+
+      final results = await Future.wait([
+        // Root event lookup by id.
+        session.fetchHistory(
+          NostrFilter(
+            kinds: const [9, 40002, 45001, 45003],
+            ids: [args.eventId],
+            limit: 1,
+          ),
+        ),
+        // Replies pointing at this root.
+        session.fetchHistory(
+          NostrFilters.forumThread(args.eventId, args.channelId),
+        ),
+      ]);
+
+      final rootEvents = results[0];
+      final replyEvents = results[1];
+      if (rootEvents.isEmpty) {
+        throw Exception('Forum thread not found: ${args.eventId}');
+      }
+      return ForumThreadResponse.fromEvents(
+        root: rootEvents.first,
+        replies: replyEvents,
+      );
+    });
+
+/// A forum event delivery bound to the community where composition began.
+///
+/// Attachment uploads can outlive their route. Capturing the relay identity,
+/// signing key, and emoji palette prevents a queued draft from being delivered
+/// to a different community after the user switches relays.
+class ForumEventDelivery {
+  final ProviderContainer _container;
+  final String _relayUrl;
+  final String? _nsec;
+  final SignedEventRelay _relay;
+  final List<CustomEmoji> _customEmoji;
+
+  ForumEventDelivery._({
+    required ProviderContainer container,
+    required String relayUrl,
+    required String? nsec,
+    required SignedEventRelay relay,
+    required List<CustomEmoji> customEmoji,
+  }) : _container = container,
+       _relayUrl = relayUrl,
+       _nsec = nsec,
+       _relay = relay,
+       _customEmoji = customEmoji;
+
+  /// Captures the active community dependencies for a future delivery.
+  factory ForumEventDelivery.capture(ProviderContainer container) {
+    final config = container.read(relayConfigProvider);
+    return ForumEventDelivery._(
+      container: container,
+      relayUrl: config.baseUrl,
+      nsec: config.nsec,
+      relay: SignedEventRelay(
+        session: container.read(relaySessionProvider.notifier),
+        nsec: config.nsec,
+      ),
+      customEmoji: List<CustomEmoji>.unmodifiable(
+        container.read(customEmojiListProvider),
+      ),
+    );
+  }
+
+  /// Creates a new forum post (kind:45001).
+  Future<void> createPost({
+    required String channelId,
+    required String content,
+    List<String> mentionPubkeys = const [],
+    List<List<String>> mediaTags = const [],
+  }) async {
+    await _submit(
+      kind: EventKind.forumPost,
+      channelId: channelId,
+      content: content,
+      mentionPubkeys: mentionPubkeys,
+      mediaTags: mediaTags,
+    );
+    _container.invalidate(forumPostsProvider(channelId));
+  }
+
+  /// Creates a reply to a forum post (kind:45003).
+  Future<void> createReply({
+    required String channelId,
+    required String parentEventId,
+    required String content,
+    List<String> mentionPubkeys = const [],
+    List<List<String>> mediaTags = const [],
+  }) async {
+    await _submit(
+      kind: EventKind.forumComment,
+      channelId: channelId,
+      parentEventId: parentEventId,
+      content: content,
+      mentionPubkeys: mentionPubkeys,
+      mediaTags: mediaTags,
+    );
+    _container.invalidate(forumPostsProvider(channelId));
+    _container.invalidate(
+      forumThreadProvider((channelId: channelId, eventId: parentEventId)),
+    );
+  }
+
+  Future<void> _submit({
+    required int kind,
+    required String channelId,
+    required String content,
+    String? parentEventId,
+    required List<String> mentionPubkeys,
+    required List<List<String>> mediaTags,
+  }) async {
+    final currentConfig = _container.read(relayConfigProvider);
+    if (currentConfig.baseUrl != _relayUrl || currentConfig.nsec != _nsec) {
+      throw StateError(
+        'Forum delivery cancelled because the active community changed',
+      );
+    }
+
+    final selfPubkey = _relay.pubkey?.toLowerCase();
+    final seen = <String>{?selfPubkey};
+    final normalizedMentions = [
+      for (final pk in mentionPubkeys)
+        if (seen.add(pk.toLowerCase())) pk,
+    ];
+
+    await _relay.submit(
+      kind: kind,
+      content: content,
+      tags: [
+        ['h', channelId],
+        if (parentEventId != null) ['e', parentEventId, '', 'reply'],
+        for (final pk in normalizedMentions) ['p', pk],
+        ...mediaTags,
+        ...buildCustomEmojiTags(content, _customEmoji),
+      ],
+    );
+  }
+}
+
+/// Deletes a forum post or reply and invalidates relevant caches.
+Future<void> deleteForumEvent(
+  WidgetRef ref, {
+  required String channelId,
+  required String eventId,
+  String? rootEventId,
+}) async {
+  final actions = ref.read(channelActionsProvider);
+  await actions.deleteMessage(channelId: channelId, eventId: eventId);
+  ref.invalidate(forumPostsProvider(channelId));
+  if (rootEventId != null) {
+    ref.invalidate(
+      forumThreadProvider((channelId: channelId, eventId: rootEventId)),
+    );
+  }
+}