youtube_explode/lib/src/videos/video_client.dart

import '../channels/channel_id.dart';
import '../common/common.dart';
import '../exceptions/exceptions.dart';
import '../reverse_engineering/responses/responses.dart';
import '../reverse_engineering/youtube_http_client.dart';
import 'closed_captions/closed_caption_client.dart';
import 'comments/comments_client.dart';
import 'videos.dart';

/// Queries related to YouTube videos.
class VideoClient {
  final YoutubeHttpClient _httpClient;

  /// Queries related to media streams of YouTube videos.
  final StreamsClient streamsClient;

  /// Queries related to closed captions of YouTube videos.
  final ClosedCaptionClient closedCaptions;

  /// Queries related to a YouTube video.
  final CommentsClient commentsClient;

  /// Initializes an instance of [VideoClient].
  VideoClient(this._httpClient)
      : streamsClient = StreamsClient(_httpClient),
        closedCaptions = ClosedCaptionClient(_httpClient),
        commentsClient = CommentsClient(_httpClient);

  /// Gets the metadata associated with the specified video.
  Future<Video> _getVideoFromWatchPage(VideoId videoId) async {
    var videoInfoResponse =
        await VideoInfoResponse.get(_httpClient, videoId.value);
    var playerResponse = videoInfoResponse.playerResponse;

    var watchPage = await WatchPage.get(_httpClient, videoId.value);
    return Video(
        videoId,
        playerResponse.videoTitle,
        playerResponse.videoAuthor,
        ChannelId(playerResponse.videoChannelId),
        playerResponse.videoUploadDate,
        playerResponse.videoDescription,
        playerResponse.videoDuration,
        ThumbnailSet(videoId.value),
        playerResponse.videoKeywords,
        Engagement(playerResponse.videoViewCount ?? 0, watchPage.videoLikeCount,
            watchPage.videoDislikeCount),
        watchPage);
  }

  Future<Video> _getVideoFromFixPlaylist(VideoId id) async {
    var playlistInfo = await PlaylistResponse.get(_httpClient, 'RD${id.value}');

    var video = playlistInfo.videos
        .firstWhere((e) => e.id == id.value, orElse: () => null);
    if (video == null) {
      throw TransientFailureException('Video not found in mix playlist');
    }

    return Video(
        id,
        video.title,
        video.author,
        video.channelId,
        video.uploadDate,
        video.description,
        video.duration,
        ThumbnailSet(id.value),
        video.keywords,
        Engagement(video.viewCount, video.likes, video.dislikes));
  }

  /// Get a [Video] instance from a [videoId]
  Future<Video> get(dynamic videoId, {bool forceWatchPage = false}) async {
    videoId = VideoId.fromString(videoId);

    if (forceWatchPage) {
      return _getVideoFromWatchPage(videoId);
    }

    try {
      return await _getVideoFromFixPlaylist(videoId);
    } on YoutubeExplodeException {
      return _getVideoFromWatchPage(videoId);
    }
  }
}