聊天文件预览与保存到网盘功能开发笔记

class SendMessage {
  final String id;
  final String sessionId;
  final String type;        // 'text', 'image', 'video', 'audio', 'file'
  final String? content;    // 文本内容
  final String? fileId;     // 关联的文件ID
  final String? fileName;   // 文件名
  final String? mimeType;   // MIME类型
  final int? fileSize;      // 文件大小
  final int? width;         // 图片/视频宽度
  final int? height;        // 图片/视频高度
  final int? duration;      // 音视频时长(ms)
  final bool isLocalFile;   // 是否为本地文件（尚未上传到S3）
  final DateTime createdAt;
  // ...
}

class FileMetadata {
  final String id;
  final String name;
  final String path;
  final bool isFolder;
  final String? mimeType;
  // ... 其他元数据
}

void _showFileActions(BuildContext context) {
  if (widget.sendMessage != null) {
    _showChatFileActions(context);  // 聊天来源菜单
  } else {
    _showNetdiskFileActions(context);  // 网盘来源菜单
  }
}

Future<void> _saveToNetdisk(BuildContext context) async {
  final message = widget.sendMessage!;
  
  // 如果不是本地文件，跳转到网盘位置
  if (!message.isLocalFile && message.fileId != null) {
    _navigateToFileLocation(message.fileId!);
    return;
  }
  
  // 选择目标文件夹
  final targetPath = await showDialog<String>(
    context: context,
    builder: (context) => FilePickerDialog(
      mode: FilePickerMode.folderOnly,
      title: '保存到',
    ),
  );
  
  if (targetPath == null) return;
  
  // 调用 adoptOrphanFile 保存
  final appState = Provider.of<AppState>(context, listen: false);
  try {
    await appState.adoptOrphanFile(
      fileId: message.fileId!,
      name: message.fileName ?? 'file',
      targetPath: targetPath,
    );
    
    if (context.mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('已保存到 $targetPath')),
      );
    }
  } catch (e) {
    if (context.mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('保存失败: $e')),
      );
    }
  }
}

Future<void> _saveTextAsFile(SendMessage message) async {
  if (message.content == null || message.content!.isEmpty) return;
  
  // 1. 选择目标文件夹
  final targetPath = await showDialog<String>(
    context: context,
    builder: (context) => FilePickerDialog(
      mode: FilePickerMode.folderOnly,
      title: '保存到',
    ),
  );
  
  if (targetPath == null) return;
  
  // 2. 生成文件名（取前20字符 + 时间戳）
  final preview = message.content!.length > 20 
      ? message.content!.substring(0, 20) 
      : message.content!;
  final safeName = preview.replaceAll(RegExp(r'[\\/:*?"<>|\n\r]'), '_');
  final timestamp = DateTime.now().millisecondsSinceEpoch;
  final fileName = '${safeName}_$timestamp.txt';
  
  // 3. 创建临时文件
  final tempDir = await getTemporaryDirectory();
  final tempFile = File('${tempDir.path}/$fileName');
  await tempFile.writeAsString(message.content!);
  
  try {
    // 4. 上传到网盘
    final appState = Provider.of<AppState>(context, listen: false);
    await appState.uploadByPath(
      localPath: tempFile.path,
      remotePath: '$targetPath/$fileName',
    );
    
    if (context.mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('已保存到 $targetPath/$fileName')),
      );
    }
  } finally {
    // 5. 清理临时文件
    if (await tempFile.exists()) {
      await tempFile.delete();
    }
  }
}

void _openImagePreview(SendMessage message, FileMetadata file) {
  Navigator.push(
    context,
    MaterialPageRoute(
      builder: (context) => ImagePreviewPage(
        file: file,
        sendMessage: message,  // 传入消息对象
      ),
    ),
  );
}

void _openVideoPlayer(SendMessage message, FileMetadata file) {
  Navigator.push(
    context,
    MaterialPageRoute(
      builder: (context) => VideoPlayerPage(
        file: file,
        sendMessage: message,  // 传入消息对象
      ),
    ),
  );
}

List<ContextMenuItem> _buildMessageMenuItems(SendMessage message) {
  final items = <ContextMenuItem>[];
  
  // 复制（文本消息）
  if (message.type == 'text' && message.content != null) {
    items.add(ContextMenuItem(
      icon: TablerIcons.copy,
      label: '复制',
      onTap: () => _copyMessage(message),
    ));
    
    // 保存为文件
    items.add(ContextMenuItem(
      icon: TablerIcons.file_download,
      label: '保存为文件',
      onTap: () => _saveTextAsFile(message),
    ));
  }
  
  // 附件消息
  if (message.fileId != null) {
    items.add(ContextMenuItem(
      icon: TablerIcons.device_floppy,
      label: '保存到网盘',
      onTap: () => _saveToNetdisk(message),
    ));
  }
  
  // 删除
  items.add(ContextMenuItem(
    icon: TablerIcons.trash,
    label: '删除',
    onTap: () => _deleteMessage(message),
  ));
  
  return items;
}

Row(
  children: [
    // 面包屑导航
    Expanded(
      child: SingleChildScrollView(
        scrollDirection: Axis.horizontal,
        child: _buildBreadcrumb(),
      ),
    ),
    // 新建文件夹按钮（仅 folderOnly 模式）
    if (widget.mode == FilePickerMode.folderOnly)
      Container(
        width: 32,
        height: 32,
        margin: const EdgeInsets.only(left: 8),
        decoration: BoxDecoration(
          shape: BoxShape.circle,
          color: theme.colorScheme.primaryContainer,
        ),
        child: IconButton(
          icon: Icon(TablerIcons.folder_plus, size: 18),
          onPressed: _showCreateFolderDialog,
          tooltip: '新建文件夹',
          padding: EdgeInsets.zero,
          constraints: const BoxConstraints(),
          color: theme.colorScheme.onPrimaryContainer,
        ),
      ),
  ],
),

Future<void> _showCreateFolderDialog() async {
  final controller = TextEditingController();
  
  final folderName = await showDialog<String>(
    context: context,
    builder: (context) => AlertDialog(
      title: const Text('新建文件夹'),
      content: TextField(
        controller: controller,
        autofocus: true,
        decoration: const InputDecoration(
          hintText: '文件夹名称',
        ),
      ),
      actions: [
        TextButton(
          onPressed: () => Navigator.pop(context),
          child: const Text('取消'),
        ),
        TextButton(
          onPressed: () => Navigator.pop(context, controller.text.trim()),
          child: const Text('创建'),
        ),
      ],
    ),
  );
  
  if (folderName == null || folderName.isEmpty) return;
  
  final appState = Provider.of<AppState>(context, listen: false);
  try {
    await appState.createFolderAt(folderName, _currentPath);
    _refreshFiles();  // 刷新文件列表
  } catch (e) {
    if (context.mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('创建失败: $e')),
      );
    }
  }
}

// 错误
await appState.createFolder(folderName, _currentPath);
 
// 正确
await appState.createFolderAt(folderName, _currentPath);

try {
  await someAsyncOperation();
  if (context.mounted) {
    ScaffoldMessenger.of(context).showSnackBar(...);
  }
} catch (e) {
  // ...
}