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,
+                  ),
+                ),
+              );
+            },
+          ),
+        ],
+      ),
+    );
+  }
+}

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

@@ -0,0 +1,228 @@
+part of '../message_content.dart';
+
+/// A decoded, paused video surface used as a posterless message preview.
+class LoadedVideoPreviewFrame {
+  /// Widget backed by the initialized native video texture.
+  final Widget child;
+
+  /// Aspect ratio reported by the video decoder.
+  final double aspectRatio;
+
+  final Future<void> Function() _dispose;
+
+  /// Creates a loaded preview frame with its resource cleanup callback.
+  const LoadedVideoPreviewFrame({
+    required this.child,
+    required this.aspectRatio,
+    required Future<void> Function() dispose,
+  }) : _dispose = dispose;
+
+  /// Releases the native decoder and any downloaded temporary file.
+  Future<void> dispose() => _dispose();
+}
+
+/// Loads a paused first-frame surface for a video URL.
+typedef VideoPreviewFrameLoader =
+    Future<LoadedVideoPreviewFrame?> Function(String url);
+
+/// Loader used when an older video event has no NIP-71 poster URL.
+final videoPreviewFrameLoaderProvider = Provider<VideoPreviewFrameLoader>((
+  ref,
+) {
+  final auth = ref.watch(mediaGetAuthServiceProvider);
+  return (url) => _loadVideoPreviewFrame(url, headers: auth.headersFor(url));
+});
+
+class _MessageVideoPreview extends HookConsumerWidget {
+  final String url;
+  final ImetaEntry? imeta;
+  final VoidCallback? onReply;
+
+  const _MessageVideoPreview({
+    required this.url,
+    required this.imeta,
+    required this.onReply,
+  });
+
+  @override
+  Widget build(BuildContext context, WidgetRef ref) {
+    final rawAspectRatio = imeta?.aspectRatio ?? (16 / 9);
+    final aspectRatio = rawAspectRatio.clamp(0.75, 1.91);
+    final posterUrl = imeta?.posterUrl;
+    final loadPreviewFrame = ref.watch(videoPreviewFrameLoaderProvider);
+    final previewFrameFuture = useMemoized(
+      () => posterUrl == null
+          ? loadPreviewFrame(url)
+          : Future<LoadedVideoPreviewFrame?>.value(),
+      [loadPreviewFrame, posterUrl, url],
+    );
+
+    useEffect(() {
+      var disposed = false;
+      LoadedVideoPreviewFrame? loadedFrame;
+      unawaited(
+        previewFrameFuture.then((frame) {
+          if (disposed) {
+            if (frame != null) unawaited(frame.dispose());
+          } else {
+            loadedFrame = frame;
+          }
+        }),
+      );
+      return () {
+        disposed = true;
+        final frame = loadedFrame;
+        if (frame != null) unawaited(frame.dispose());
+      };
+    }, [previewFrameFuture]);
+
+    return Padding(
+      padding: const EdgeInsets.only(top: Grid.half),
+      child: GestureDetector(
+        onTap: () => openVideoViewer(
+          context,
+          videoUrl: url,
+          posterUrl: posterUrl,
+          onReply: onReply,
+        ),
+        child: _MessageMediaPreviewFrame(
+          previewKey: ValueKey('message-media-video-preview:$url'),
+          backgroundColor: Colors.black,
+          child: AspectRatio(
+            aspectRatio: aspectRatio.toDouble(),
+            child: Stack(
+              fit: StackFit.expand,
+              children: [
+                if (posterUrl != null)
+                  MediaImage(
+                    url: posterUrl,
+                    fit: BoxFit.cover,
+                    errorBuilder: (_, _, _) => _MediaPreviewFallback(
+                      icon: LucideIcons.video,
+                      label: context.l10n.videoPreviewUnavailable,
+                    ),
+                  )
+                else
+                  FutureBuilder<LoadedVideoPreviewFrame?>(
+                    future: previewFrameFuture,
+                    builder: (context, snapshot) {
+                      final frame = snapshot.data;
+                      if (frame == null) {
+                        return _MediaPreviewFallback(
+                          icon: LucideIcons.video,
+                          label: context.l10n.videoAttachment,
+                        );
+                      }
+                      return ColoredBox(
+                        key: ValueKey('message-media-video-first-frame:$url'),
+                        color: Colors.black,
+                        child: Center(
+                          child: AspectRatio(
+                            aspectRatio: frame.aspectRatio,
+                            child: frame.child,
+                          ),
+                        ),
+                      );
+                    },
+                  ),
+                const ColoredBox(color: Color.fromRGBO(0, 0, 0, 0.28)),
+                Center(
+                  child: Container(
+                    width: 52,
+                    height: 52,
+                    decoration: const BoxDecoration(
+                      color: Color.fromRGBO(0, 0, 0, 0.6),
+                      shape: BoxShape.circle,
+                    ),
+                    child: const Icon(
+                      LucideIcons.play,
+                      color: Colors.white,
+                      size: 24,
+                    ),
+                  ),
+                ),
+                Positioned(
+                  left: Grid.xxs,
+                  right: Grid.xxs,
+                  bottom: Grid.xxs,
+                  child: Text(
+                    context.l10n.video,
+                    style: context.textTheme.labelSmall?.copyWith(
+                      color: Colors.white,
+                      fontWeight: FontWeight.w600,
+                    ),
+                  ),
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}
+
+Future<LoadedVideoPreviewFrame?> _loadVideoPreviewFrame(
+  String url, {
+  required Map<String, String> headers,
+}) async {
+  final uri = Uri.tryParse(url);
+  if (uri == null || !uri.hasScheme) return null;
+
+  VideoPlayerController? controller;
+  Future<void> disposeResources() async {
+    final currentController = controller;
+    controller = null;
+    if (currentController != null) await currentController.dispose();
+  }
+
+  Future<bool> initialize(VideoPlayerController candidate) async {
+    controller = candidate;
+    await candidate.initialize();
+    final duration = candidate.value.duration;
+    if (duration > const Duration(milliseconds: 100)) {
+      await candidate.seekTo(const Duration(milliseconds: 100));
+    }
+    await candidate.pause();
+    return candidate.value.isInitialized;
+  }
+
+  try {
+    final networkController = VideoPlayerController.networkUrl(
+      uri,
+      httpHeaders: headers,
+      videoPlayerOptions: VideoPlayerOptions(mixWithOthers: true),
+    );
+    if (!await initialize(networkController)) {
+      await disposeResources();
+      return null;
+    }
+  } on MissingPluginException {
+    await disposeResources();
+    return null;
+  } on UnimplementedError {
+    await disposeResources();
+    return null;
+  } catch (_) {
+    // A timeline preview must stay bounded: falling back to a local file here
+    // would fully download every posterless video encountered while scrolling.
+    // The full-screen viewer can use its authenticated fallback after a tap.
+    await disposeResources();
+    return null;
+  }
+
+  final initializedController = controller;
+  if (initializedController == null) return null;
+  var didDispose = false;
+  return LoadedVideoPreviewFrame(
+    aspectRatio: initializedController.value.aspectRatio > 0
+        ? initializedController.value.aspectRatio
+        : 16 / 9,
+    child: VideoPlayer(initializedController),
+    dispose: () async {
+      if (didDispose) return;
+      didDispose = true;
+      await disposeResources();
+    },
+  );
+}