startVideoDownload method

Implementation

void startVideoDownload() {
  // 检查视频源是否存在
  if (_widgetData?.videoSource == null) return;

  // 检查下载保存目录是否存在
  if (downloadSavePath == null || downloadSavePath!.isEmpty) {
    SnackBarUtil.error(
      _context,
      "Please set AliPlayerWidgetGlobalSetting.setStoragePaths first.",
    );
    return;
  }

  // 检查是否已经下载完成，如果已完成则提示用户
  if (downloadStateNotifier.value is DownloadCompletedState) {
    final DownloadCompletedState state =
        downloadStateNotifier.value as DownloadCompletedState;
    SnackBarUtil.success(_context,
        "This video has already been downloaded. SavePath: ${state.downloadFile}");
    return;
  } else if (downloadStateNotifier.value is DownloadingState) {
    // 如果处于加载状态，直接return
    return;
  }

  // 设置下载保存目录
  _aliDownloader.setSaveDir(downloadSavePath!);

  String? vid; // 视频ID
  Future<dynamic>? downloadAction;

  // 根据不同视频源类型执行相应下载逻辑
  if (_widgetData?.videoSource is VidStsVideoSource) {
    // 处理 STS 类型视频源的下载准备
    final stsSource = _widgetData?.videoSource as VidStsVideoSource;
    vid = stsSource.vid;
    String accessKeyId = stsSource.accessKeyId;
    String accessKeySecret = stsSource.accessKeySecret;
    String securityToken = stsSource.securityToken;

    downloadAction = _aliDownloader.prepare(
      FlutterAvpdef.DOWNLOADTYPE_STS,
      vid,
      accessKeyId: accessKeyId,
      accessKeySecret: accessKeySecret,
      securityToken: securityToken,
    );
  } else if (_widgetData?.videoSource is VidAuthVideoSource) {
    // 处理 Auth 类型视频源的下载准备
    final authSource = _widgetData?.videoSource as VidAuthVideoSource;
    vid = authSource.vid;
    String playAuth = authSource.playAuth;

    downloadAction = _aliDownloader.prepare(
      FlutterAvpdef.DOWNLOADTYPE_AUTH,
      vid,
      playAuth: playAuth,
    );
  }

  if (vid != null && vid.isNotEmpty) {
    downloadAction?.then((value) {
      _executeDownloadWithMediaInfo(vid!, value);
    }).catchError((error, stack) {
      _handleDownloadError(error);
    });
  } else {
    // UrlVideoSource is not support;
    downloadStateNotifier.value = const DownloadErrorState(
      errorCode: "Video Source Error",
      errorMessage: "Unsupported video source. Only vid source is supported.",
    );
  }
}