feat: import Chinese-localized Buzz source snapshot

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

mobile/lib/features/channels/message_content/media_carousel.dart

@@ -0,0 +1,303 @@
+part of '../message_content.dart';
+
+const _messageMediaCarouselHeight = 220.0;
+
+@immutable
+class _MessageGalleryItem {
+  final String url;
+  final String semanticLabel;
+  final double? aspectRatio;
+
+  const _MessageGalleryItem({
+    required this.url,
+    required this.semanticLabel,
+    required this.aspectRatio,
+  });
+}
+
+@immutable
+class _TrailingImageGallery {
+  final String content;
+  final List<_MessageGalleryItem> items;
+
+  const _TrailingImageGallery({required this.content, required this.items});
+}
+
+class _MessageGalleryPrecache extends HookWidget {
+  final List<ImageProvider<Object>> providers;
+  final int focusedIndex;
+
+  const _MessageGalleryPrecache({
+    required this.providers,
+    required this.focusedIndex,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final providerSignature = Object.hashAll(providers);
+    useEffect(() {
+      var cancelled = false;
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        if (cancelled || !context.mounted) {
+          return;
+        }
+        for (var index = focusedIndex - 2; index <= focusedIndex + 2; index++) {
+          if (index < 0 || index >= providers.length) {
+            continue;
+          }
+          unawaited(
+            precacheImage(providers[index], context, onError: (_, _) {}),
+          );
+        }
+      });
+      return () => cancelled = true;
+    }, [focusedIndex, providerSignature]);
+    return const SizedBox.shrink();
+  }
+}
+
+_TrailingImageGallery? _extractTrailingImageGallery(
+  String content,
+  Map<String, ImetaEntry> imetaByUrl,
+  String fallbackLabel,
+) {
+  final lines = content.split('\n');
+  var cursor = lines.length - 1;
+  while (cursor >= 0 && lines[cursor].trim().isEmpty) {
+    cursor -= 1;
+  }
+
+  final items = <_MessageGalleryItem>[];
+  final imagePattern = RegExp(r'^!\[([^\]]*)\]\((https?://[^)\s]+)\)$');
+  while (cursor >= 0) {
+    final match = imagePattern.firstMatch(lines[cursor].trim());
+    if (match == null) break;
+    final url = match.group(2)!;
+    final imeta = imetaByUrl[url];
+    if (classifyMediaUrl(url, imeta: imeta) == MessageMediaKind.video) {
+      break;
+    }
+    final markdownLabel = match.group(1)?.trim();
+    items.insert(
+      0,
+      _MessageGalleryItem(
+        url: url,
+        semanticLabel:
+            imeta?.alt ??
+            (markdownLabel?.isNotEmpty == true
+                ? markdownLabel!
+                : fallbackLabel),
+        aspectRatio: imeta?.aspectRatio,
+      ),
+    );
+    cursor -= 1;
+  }
+
+  if (items.length < 2) return null;
+  return _TrailingImageGallery(
+    content: lines.take(cursor + 1).join('\n').trimRight(),
+    items: items,
+  );
+}
+
+class _MessageImageCarousel extends HookConsumerWidget {
+  final List<_MessageGalleryItem> items;
+  final double leadingOverflow;
+  final double trailingOverflow;
+  final VoidCallback? onReply;
+  final MediaViewerMoreAction? onMore;
+
+  const _MessageImageCarousel({
+    super.key,
+    required this.items,
+    required this.leadingOverflow,
+    required this.trailingOverflow,
+    required this.onReply,
+    required this.onMore,
+  });
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final itemSignature = items.map((item) => item.url).join('\u0000');
+    final heroTags = useMemoized(
+      () => [for (var index = 0; index < items.length; index++) Object()],
+      [itemSignature],
+    );
+    final controller = usePageController(viewportFraction: 0.9);
+    final currentIndex = useState(0);
+    final mediaAuth = ref.watch(mediaGetAuthServiceProvider);
+    final mediaClient = ref.watch(mediaHttpClientProvider);
+
+    return Padding(
+      padding: const EdgeInsets.only(top: Grid.half),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          Text(
+            context.l10n.imagesCount(items.length),
+            key: const ValueKey('message-media-carousel-count'),
+            style: context.textTheme.labelMedium?.copyWith(
+              color: context.colors.onSurfaceVariant,
+              fontWeight: FontWeight.w400,
+            ),
+          ),
+          const SizedBox(height: Grid.half + Grid.quarter),
+          LayoutBuilder(
+            builder: (context, constraints) {
+              final contentWidth = constraints.hasBoundedWidth
+                  ? constraints.maxWidth
+                  : _messageMediaMaxWidth(context);
+              final carouselWidth =
+                  contentWidth + leadingOverflow + trailingOverflow;
+              final leadingExtent = leadingOverflow;
+              final isLeftToRight =
+                  Directionality.of(context) == TextDirection.ltr;
+              final itemTrailingPaddings = [
+                for (var index = 0; index < items.length; index++)
+                  index == items.length - 1 ? Grid.gutter : Grid.half,
+              ];
+              final previewDecodeWidths = [
+                for (var index = 0; index < items.length; index++)
+                  math.max(
+                    1.0,
+                    carouselWidth * controller.viewportFraction -
+                        itemTrailingPaddings[index],
+                  ),
+              ];
+              final devicePixelRatio = MediaQuery.devicePixelRatioOf(context);
+              final previewProviders = [
+                for (var index = 0; index < items.length; index++)
+                  ResizeImage.resizeIfNeeded(
+                    (previewDecodeWidths[index] * devicePixelRatio).ceil(),
+                    null,
+                    MediaImageProvider(
+                      url: items[index].url,
+                      auth: mediaAuth,
+                      client: mediaClient,
+                    ),
+                  ),
+              ];
+              final viewerItems = [
+                for (var index = 0; index < items.length; index++)
+                  MediaViewerImage(
+                    url: items[index].url,
+                    heroTag: heroTags[index],
+                    semanticLabel: items[index].semanticLabel,
+                    previewDecodeWidth: previewDecodeWidths[index],
+                    aspectRatio: items[index].aspectRatio,
+                    preloadProvider: previewProviders[index],
+                  ),
+              ];
+              final carousel = SizedBox(
+                key: const ValueKey('message-media-carousel'),
+                width: carouselWidth,
+                height: _messageMediaCarouselHeight,
+                child: PageView.builder(
+                  controller: controller,
+                  allowImplicitScrolling: true,
+                  // Keep the first image aligned with the message body, but
+                  // allow later pages to paint through the avatar gutter as
+                  // the row scrolls.
+                  clipBehavior: Clip.none,
+                  padEnds: false,
+                  itemCount: items.length,
+                  onPageChanged: (index) => currentIndex.value = index,
+                  itemBuilder: (context, index) {
+                    final item = items[index];
+                    return Padding(
+                      key: ValueKey('message-media-carousel-page:${item.url}'),
+                      padding: EdgeInsetsDirectional.only(
+                        end: itemTrailingPaddings[index],
+                      ),
+                      child: Semantics(
+                        button: true,
+                        excludeSemantics: true,
+                        label: context.l10n.openMedia(item.semanticLabel),
+                        child: GestureDetector(
+                          key: ValueKey(
+                            'message-media-carousel-item:${item.url}',
+                          ),
+                          onTap: () => openImageViewer(
+                            context,
+                            imageUrl: item.url,
+                            heroTag: heroTags[index],
+                            semanticLabel: item.semanticLabel,
+                            previewDecodeWidth: previewDecodeWidths[index],
+                            aspectRatio: item.aspectRatio,
+                            galleryItems: viewerItems,
+                            initialIndex: index,
+                            onReply: onReply,
+                            onMore: onMore,
+                          ),
+                          child: Container(
+                            clipBehavior: Clip.antiAlias,
+                            decoration: BoxDecoration(
+                              color: context.colors.surfaceContainerHighest,
+                              borderRadius: BorderRadius.circular(Radii.md),
+                              border: Border.all(
+                                color: context.colors.outlineVariant,
+                              ),
+                            ),
+                            child: MediaViewerHero(
+                              tag: heroTags[index],
+                              child: ClipRRect(
+                                borderRadius: BorderRadius.circular(Radii.md),
+                                child: MediaImage(
+                                  url: item.url,
+                                  decodeWidth: previewDecodeWidths[index],
+                                  fit: BoxFit.cover,
+                                  semanticLabel: item.semanticLabel,
+                                  errorBuilder: (_, _, _) =>
+                                      _MediaPreviewFallback(
+                                        icon: LucideIcons.imageOff,
+                                        label: context.l10n.imageUnavailable,
+                                      ),
+                                ),
+                              ),
+                            ),
+                          ),
+                        ),
+                      ),
+                    );
+                  },
+                ),
+              );
+
+              final carouselSurface = Stack(
+                clipBehavior: Clip.none,
+                children: [
+                  carousel,
+                  _MessageGalleryPrecache(
+                    providers: previewProviders,
+                    focusedIndex: currentIndex.value,
+                  ),
+                ],
+              );
+
+              if (leadingExtent <= 0 && trailingOverflow <= 0) {
+                return carouselSurface;
+              }
+              return SizedBox(
+                width: contentWidth,
+                height: _messageMediaCarouselHeight,
+                child: OverflowBox(
+                  alignment: AlignmentDirectional.centerStart,
+                  minWidth: carouselWidth,
+                  maxWidth: carouselWidth,
+                  child: Transform.translate(
+                    offset: Offset(
+                      isLeftToRight ? -leadingExtent : leadingExtent,
+                      0,
+                    ),
+                    child: carouselSurface,
+                  ),
+                ),
+              );
+            },
+          ),
+        ],
+      ),
+    );
+  }
+}