feat: import Chinese-localized Buzz source snapshot

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

mobile/lib/features/channels/emoji_picker/emoji_grid.dart

@@ -0,0 +1,344 @@
+part of '../emoji_picker.dart';
+
+/// Emoji per row. Matches desktop's `perLine={8}`.
+const _emojiPerLine = 8;
+
+/// Rendered glyph size. Standard and custom emoji share this so a community's
+/// own emoji sit in the grid at the same weight as the native set.
+const _emojiGlyphSize = 28.0;
+
+/// Height of one grid cell. Fixed rather than derived from the cell width so
+/// section offsets are exact — [_EmojiSection.extent] is what the rail scrolls
+/// to, and a width-dependent row height would make it a guess.
+const _cellExtent = 40.0;
+
+/// Height of a pinned section header, padding included. Also fixed, for the
+/// same reason.
+const _sectionHeaderExtent = 28.0;
+
+/// Cells divide the content width evenly with no gaps, the way emoji-mart lays
+/// its grid out; the space around each glyph comes from the cell being larger
+/// than the glyph.
+SliverGridDelegate get _gridDelegate =>
+    const SliverGridDelegateWithFixedCrossAxisCount(
+      crossAxisCount: _emojiPerLine,
+      mainAxisExtent: _cellExtent,
+    );
+
+/// One labelled run of tiles in the continuous grid.
+///
+/// Sections know their own scroll extent so the rail can jump to them without
+/// the grid having been laid out — with ~1.9k emoji most sections are far
+/// off-screen, so there is no render object to measure or `ensureVisible`.
+class _EmojiSection {
+  final String id;
+  final String label;
+  final IconData icon;
+  final int itemCount;
+  final Widget Function(BuildContext context, int index) itemBuilder;
+
+  const _EmojiSection({
+    required this.id,
+    required this.label,
+    required this.icon,
+    required this.itemCount,
+    required this.itemBuilder,
+  });
+
+  int get rowCount => (itemCount / _emojiPerLine).ceil();
+
+  double get extent => _sectionHeaderExtent + rowCount * _cellExtent;
+}
+
+/// Offset of each section's header, in scroll order. Element `i` is where the
+/// rail should land for section `i`.
+List<double> _sectionOffsets(List<_EmojiSection> sections) {
+  final offsets = <double>[];
+  var running = 0.0;
+  for (final section in sections) {
+    offsets.add(running);
+    running += section.extent;
+  }
+  return offsets;
+}
+
+/// Which section owns [offset] — the one whose header is pinned right now.
+int _activeSectionIndex(List<double> offsets, double offset) {
+  var active = 0;
+  for (var i = 0; i < offsets.length; i++) {
+    // Half a header of slack so the highlight flips as a header reaches the
+    // top rather than a pixel before.
+    if (offsets[i] <= offset + _sectionHeaderExtent / 2) active = i;
+  }
+  return active;
+}
+
+/// One tappable standard emoji.
+///
+/// [keyPrefix] exists because the frequently-used section repeats emoji that
+/// also appear in their own category, and both are in the same scroll view — two
+/// widgets keyed `emoji-tile-fire` would be indistinguishable to a test.
+class _EmojiTile extends StatelessWidget {
+  final EmojiEntry entry;
+  final VoidCallback onTap;
+  final String keyPrefix;
+
+  const _EmojiTile({
+    required this.entry,
+    required this.onTap,
+    this.keyPrefix = 'emoji-tile',
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return GestureDetector(
+      key: ValueKey('$keyPrefix-${entry.tileId}'),
+      onTap: onTap,
+      behavior: HitTestBehavior.opaque,
+      child: Semantics(
+        button: true,
+        label: entry.name,
+        child: Center(
+          child: NativeEmojiGlyph(emoji: entry.native, size: _emojiGlyphSize),
+        ),
+      ),
+    );
+  }
+}
+
+/// One tappable custom (image) emoji. Same cell and same glyph size as
+/// [_EmojiTile] — a community's emoji shouldn't be laid out on its own looser
+/// grid, which is what made the custom tab read as a different component.
+class _CustomEmojiTile extends StatelessWidget {
+  final CustomEmoji emoji;
+  final VoidCallback onTap;
+  final String keyPrefix;
+
+  const _CustomEmojiTile({
+    required this.emoji,
+    required this.onTap,
+    this.keyPrefix = 'emoji-tile-custom',
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return GestureDetector(
+      key: ValueKey('$keyPrefix-${emoji.shortcode}'),
+      onTap: onTap,
+      behavior: HitTestBehavior.opaque,
+      child: Tooltip(
+        message: ':${emoji.shortcode}:',
+        child: Center(
+          child: CustomEmojiImage(
+            shortcode: emoji.shortcode,
+            url: emoji.url,
+            size: _emojiGlyphSize,
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+/// Every section in one scroll view, headers pinning as they reach the top.
+///
+/// Replaces the old tab-per-category swap: the rail is a shortcut into a single
+/// list, not a set of separate pages, which is how both desktop and every
+/// system emoji keyboard behave.
+class _ContinuousEmojiGrid extends StatelessWidget {
+  final List<_EmojiSection> sections;
+  final ScrollController controller;
+
+  const _ContinuousEmojiGrid({
+    required this.sections,
+    required this.controller,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return CustomScrollView(
+      key: const ValueKey('emoji-picker-grid'),
+      controller: controller,
+      slivers: [
+        for (final section in sections)
+          SliverMainAxisGroup(
+            key: ValueKey('emoji-section-${section.id}'),
+            slivers: [
+              SliverPersistentHeader(
+                pinned: true,
+                delegate: _SectionHeaderDelegate(section.label),
+              ),
+              SliverPadding(
+                padding: const EdgeInsets.symmetric(horizontal: Grid.gutter),
+                sliver: SliverGrid.builder(
+                  gridDelegate: _gridDelegate,
+                  itemCount: section.itemCount,
+                  itemBuilder: section.itemBuilder,
+                ),
+              ),
+            ],
+          ),
+        // Clear the home indicator so the last row isn't half-swallowed. Sits
+        // outside the sections so it doesn't skew their offsets.
+        SliverToBoxAdapter(
+          child: SizedBox(
+            height: MediaQuery.viewPaddingOf(context).bottom + Grid.xxs,
+          ),
+        ),
+      ],
+    );
+  }
+}
+
+/// Search results: custom emoji first (a community's own emoji are the ones a
+/// user is most likely hunting for by name), then the standard set.
+class _EmojiSearchResults extends StatelessWidget {
+  final List<EmojiEntry> entries;
+  final List<CustomEmoji> customEmoji;
+  final void Function(String emoji) onSelect;
+
+  const _EmojiSearchResults({
+    required this.entries,
+    required this.customEmoji,
+    required this.onSelect,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    if (entries.isEmpty && customEmoji.isEmpty) {
+      return _EmojiEmptyState(
+        icon: LucideIcons.searchX,
+        message: context.l10n.emojiNoResults,
+      );
+    }
+
+    return CustomScrollView(
+      key: const ValueKey('emoji-picker-search-results'),
+      slivers: [
+        if (customEmoji.isNotEmpty) ...[
+          _SectionHeader(label: context.l10n.emojiCustom),
+          SliverPadding(
+            padding: const EdgeInsets.symmetric(horizontal: Grid.gutter),
+            sliver: SliverGrid.builder(
+              gridDelegate: _gridDelegate,
+              itemCount: customEmoji.length,
+              itemBuilder: (context, index) {
+                final entry = customEmoji[index];
+                return _CustomEmojiTile(
+                  emoji: entry,
+                  onTap: () => onSelect(':${entry.shortcode}:'),
+                );
+              },
+            ),
+          ),
+        ],
+        if (entries.isNotEmpty) ...[
+          if (customEmoji.isNotEmpty)
+            _SectionHeader(label: context.l10n.emojiStandard),
+          SliverPadding(
+            padding: const EdgeInsets.symmetric(horizontal: Grid.gutter),
+            sliver: SliverGrid.builder(
+              gridDelegate: _gridDelegate,
+              itemCount: entries.length,
+              itemBuilder: (context, index) {
+                final entry = entries[index];
+                return _EmojiTile(
+                  entry: entry,
+                  onTap: () => onSelect(entry.native),
+                );
+              },
+            ),
+          ),
+        ],
+        SliverToBoxAdapter(
+          child: SizedBox(
+            height: MediaQuery.viewPaddingOf(context).bottom + Grid.xxs,
+          ),
+        ),
+      ],
+    );
+  }
+}
+
+/// Pinned header for a section of the continuous grid. Opaque, so rows scroll
+/// under it rather than showing through.
+class _SectionHeaderDelegate extends SliverPersistentHeaderDelegate {
+  final String label;
+
+  const _SectionHeaderDelegate(this.label);
+
+  @override
+  double get minExtent => _sectionHeaderExtent;
+
+  @override
+  double get maxExtent => _sectionHeaderExtent;
+
+  @override
+  Widget build(
+    BuildContext context,
+    double shrinkOffset,
+    bool overlapsContent,
+  ) {
+    return Container(
+      color: context.colors.surfaceContainerHighest,
+      alignment: Alignment.centerLeft,
+      padding: const EdgeInsets.symmetric(horizontal: Grid.gutter),
+      child: Text(label, style: _sectionLabelStyle(context)),
+    );
+  }
+
+  @override
+  bool shouldRebuild(_SectionHeaderDelegate oldDelegate) =>
+      oldDelegate.label != label;
+}
+
+/// Non-pinned header, for the search results list.
+class _SectionHeader extends StatelessWidget {
+  final String label;
+
+  const _SectionHeader({required this.label});
+
+  @override
+  Widget build(BuildContext context) {
+    return SliverToBoxAdapter(
+      child: Container(
+        height: _sectionHeaderExtent,
+        alignment: Alignment.centerLeft,
+        padding: const EdgeInsets.symmetric(horizontal: Grid.gutter),
+        child: Text(label, style: _sectionLabelStyle(context)),
+      ),
+    );
+  }
+}
+
+TextStyle? _sectionLabelStyle(BuildContext context) =>
+    context.textTheme.labelMedium?.copyWith(
+      color: context.colors.onSurfaceVariant,
+      fontWeight: FontWeight.w600,
+    );
+
+class _EmojiEmptyState extends StatelessWidget {
+  final IconData icon;
+  final String message;
+
+  const _EmojiEmptyState({required this.icon, required this.message});
+
+  @override
+  Widget build(BuildContext context) {
+    return Center(
+      child: Column(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          Icon(icon, size: Grid.md, color: context.colors.onSurfaceVariant),
+          const SizedBox(height: Grid.xxs),
+          Text(
+            message,
+            style: context.textTheme.bodySmall?.copyWith(
+              color: context.colors.onSurfaceVariant,
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}