feat: import Chinese-localized Buzz source snapshot

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

mobile/lib/features/channels/recent_emoji_provider.dart

@@ -0,0 +1,190 @@
+import 'dart:convert';
+
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+
+import '../../shared/relay/relay.dart';
+import '../../shared/theme/theme_provider.dart';
+
+/// Frequently-used emoji, ranked and persisted.
+///
+/// Mirrors desktop's `useQuickReactionEmojis` (`desktop/src/features/messages/
+/// ui/useQuickReactionEmojis.ts`): rank by use count, break ties by recency,
+/// cap the stored set. Same storage key shape, so the two clients describe the
+/// same concept even though the stores are per-device.
+///
+/// Persistence is namespaced by community (relay) and account pubkey, matching
+/// `ComposeDraftsNotifier` — reaction history is user behaviour and must not
+/// leak across an in-place community or account switch.
+const _recentEmojiPrefsKey = 'buzz.quick-reaction-emojis.v1';
+
+/// Desktop's `DEFAULT_QUICK_REACTIONS`, plus one mobile-only slot that fits in
+/// the compact action sheet, used until the user has reacted enough to fill it.
+const defaultQuickEmojis = <String>[
+  '\u{1F44D}',
+  '\u{2764}\u{FE0F}',
+  '\u{1F602}',
+  '\u{1F389}',
+  '\u{1F525}',
+];
+
+/// Desktop's `MAX_STORED_REACTIONS`.
+const _maxStoredEmoji = 24;
+
+/// One persisted frequently-used emoji ranking entry.
+///
+/// [emoji] is the Unicode glyph or custom shortcode, [count] is how many times
+/// it has been selected, and [lastUsedAt] is the most recent selection time in
+/// milliseconds since the Unix epoch.
+class RecentEmojiEntry {
+  /// The Unicode glyph or `:shortcode:` value that was selected.
+  final String emoji;
+
+  /// Number of recorded selections for [emoji].
+  final int count;
+
+  /// Most recent selection time in milliseconds since the Unix epoch.
+  final int lastUsedAt;
+
+  /// Creates a persisted ranking entry for [emoji].
+  const RecentEmojiEntry({
+    required this.emoji,
+    required this.count,
+    required this.lastUsedAt,
+  });
+
+  Map<String, dynamic> toJson() => {
+    'emoji': emoji,
+    'count': count,
+    'lastUsedAt': lastUsedAt,
+  };
+
+  /// Returns null for anything malformed, so one bad record can't poison the
+  /// whole list.
+  static RecentEmojiEntry? fromJson(dynamic raw) {
+    if (raw is! Map) return null;
+    final emoji = raw['emoji'];
+    if (emoji is! String || emoji.trim().isEmpty) return null;
+    final count = raw['count'];
+    final lastUsedAt = raw['lastUsedAt'];
+    return RecentEmojiEntry(
+      emoji: emoji,
+      count: count is int && count > 0 ? count : 1,
+      lastUsedAt: lastUsedAt is int && lastUsedAt > 0 ? lastUsedAt : 0,
+    );
+  }
+}
+
+/// Sort by count desc, then most-recent-first — desktop's `sortEntries`.
+List<RecentEmojiEntry> sortRecentEmoji(List<RecentEmojiEntry> entries) {
+  final sorted = [...entries];
+  sorted.sort((left, right) {
+    final byCount = right.count - left.count;
+    if (byCount != 0) return byCount;
+    return right.lastUsedAt - left.lastUsedAt;
+  });
+  return sorted;
+}
+
+/// Record [emoji] against [entries], returning the new capped, sorted list.
+/// Pure so it can be tested without SharedPreferences.
+List<RecentEmojiEntry> recordRecentEmoji(
+  List<RecentEmojiEntry> entries,
+  String emoji, {
+  required int now,
+}) {
+  if (emoji.trim().isEmpty) return entries;
+  final next = <RecentEmojiEntry>[];
+  var matched = false;
+  for (final entry in entries) {
+    if (entry.emoji == emoji) {
+      matched = true;
+      next.add(
+        RecentEmojiEntry(emoji: emoji, count: entry.count + 1, lastUsedAt: now),
+      );
+    } else {
+      next.add(entry);
+    }
+  }
+  if (!matched) {
+    next.add(RecentEmojiEntry(emoji: emoji, count: 1, lastUsedAt: now));
+  }
+  final sorted = sortRecentEmoji(next);
+  return sorted.length <= _maxStoredEmoji
+      ? sorted
+      : sorted.sublist(0, _maxStoredEmoji);
+}
+
+class RecentEmojiNotifier extends Notifier<List<RecentEmojiEntry>> {
+  late String _prefsKey;
+
+  @override
+  List<RecentEmojiEntry> build() {
+    final config = ref.watch(relayConfigProvider);
+    final pubkey = ref.watch(myPubkeyProvider) ?? 'anon';
+    _prefsKey = '$_recentEmojiPrefsKey:${config.baseUrl}:$pubkey';
+
+    final raw = ref.read(savedPrefsProvider).getString(_prefsKey);
+    if (raw == null || raw.isEmpty) return const [];
+    try {
+      final decoded = jsonDecode(raw);
+      if (decoded is! List) return const [];
+      return sortRecentEmoji(
+        decoded.map(RecentEmojiEntry.fromJson).nonNulls.toList(),
+      );
+    } catch (_) {
+      return const [];
+    }
+  }
+
+  /// Record one use of [emoji]. Called from every place a user picks an emoji:
+  /// the picker, the quick-reaction row, and toggling an existing pill on.
+  void record(String emoji) {
+    final next = recordRecentEmoji(
+      state,
+      emoji,
+      now: DateTime.now().millisecondsSinceEpoch,
+    );
+    if (identical(next, state)) return;
+    state = next;
+    ref
+        .read(savedPrefsProvider)
+        .setString(
+          _prefsKey,
+          jsonEncode(next.map((entry) => entry.toJson()).toList()),
+        );
+  }
+}
+
+final recentEmojiProvider =
+    NotifierProvider<RecentEmojiNotifier, List<RecentEmojiEntry>>(
+      RecentEmojiNotifier.new,
+    );
+
+/// The top [limit] emoji for a quick-reaction row, topped up with
+/// [defaultQuickEmojis] so the row is never short. Custom-emoji shortcodes are
+/// dropped when they are no longer in the community palette — desktop's
+/// `canRenderQuickReactionEmoji` guard, which stops a removed custom emoji from
+/// rendering as literal `:shortcode:` text.
+List<String> quickReactionEmoji(
+  List<RecentEmojiEntry> entries, {
+  required Set<String> customShortcodes,
+  int limit = 5,
+}) {
+  final result = <String>[];
+  void add(String emoji) {
+    if (result.length >= limit || result.contains(emoji)) return;
+    if (emoji.startsWith(':') && emoji.endsWith(':')) {
+      final shortcode = emoji.substring(1, emoji.length - 1).toLowerCase();
+      if (!customShortcodes.contains(shortcode)) return;
+    }
+    result.add(emoji);
+  }
+
+  for (final entry in entries) {
+    add(entry.emoji);
+  }
+  for (final emoji in defaultQuickEmojis) {
+    add(emoji);
+  }
+  return result;
+}