youtube_explode/lib/src/reverse_engineering/responses/playlist_page.dart

import 'dart:convert';

import 'package:collection/collection.dart';
import 'package:html/dom.dart';
import 'package:html/parser.dart' as parser;

import '../../../youtube_explode_dart.dart';
import '../../extensions/helpers_extension.dart';
import '../../retry.dart';
import '../youtube_http_client.dart';

///
class PlaylistPage {
  ///
  final String playlistId;
  final Document? root;

  late final _InitialData initialData = getInitialData();
  _InitialData? _initialData;

  ///
  _InitialData getInitialData() {
    if (_initialData != null) {
      return _initialData!;
    }

    final scriptText = root!.querySelectorAll('script').map((e) => e.text).toList(growable: false);

    return scriptText.extractGenericData(
        (obj) => _InitialData(obj),
        () => TransientFailureException(
            'Failed to retrieve initial data from the search page, please report this to the project GitHub page.'));
  }

  ///
  PlaylistPage(this.root, this.playlistId, [_InitialData? initialData]) : _initialData = initialData;

  ///
  Future<PlaylistPage?> nextPage(YoutubeHttpClient httpClient) async {
    if (initialData.continuationToken == null) {
      return null;
    }
    return get(httpClient, playlistId, token: initialData.continuationToken);
  }

  ///
  static Future<PlaylistPage> get(YoutubeHttpClient httpClient, String id, {String? token}) {
    if (token != null && token.isNotEmpty) {
      var url = 'https://www.youtube.com/youtubei/v1/guide?key=AIzaSyAO_FJ2SlqU8Q4STEHLGCilw_Y9_11qcW8';

      return retry(() async {
        var body = {
          'context': const {
            'client': {'hl': 'en', 'clientName': 'WEB', 'clientVersion': '2.20200911.04.00'}
          },
          'continuation': token
        };

        var raw = await httpClient.post(Uri.parse(url), body: json.encode(body));
        return PlaylistPage(null, id, _InitialData(json.decode(raw.body)));
      });
      // Ask for next page,

    }
    var url = 'https://www.youtube.com/playlist?list=$id&hl=en&persist_hl=1';
    return retry(() async {
      var raw = await httpClient.getString(url);
      return PlaylistPage.parse(raw, id);
    });
    // ask for next page
  }

  ///
  PlaylistPage.parse(String raw, this.playlistId) : root = parser.parse(raw);
}

class _InitialData {
  // Json parsed map
  final Map<String, dynamic> root;

  _InitialData(this.root);

  late final String? title = root.get('metadata')?.get('playlistMetadataRenderer')?.getT<String>('title');

  late final String? author = root
      .get('sidebar')
      ?.get('playlistSidebarRenderer')
      ?.getList('items')
      ?.elementAtSafe(1)
      ?.get('playlistSidebarSecondaryInfoRenderer')
      ?.get('videoOwner')
      ?.get('videoOwnerRenderer')
      ?.get('title')
      ?.getT<List<dynamic>>('runs')
      ?.parseRuns();

  late final String? description = root.get('metadata')?.get('playlistMetadataRenderer')?.getT<String>('description');

  late final int? viewCount = root
      .get('sidebar')
      ?.get('playlistSidebarRenderer')
      ?.getList('items')
      ?.firstOrNull
      ?.get('playlistSidebarPrimaryInfoRenderer')
      ?.getList('stats')
      ?.elementAtSafe(1)
      ?.getT<String>('simpleText')
      ?.parseInt();

  late final String? continuationToken = (videosContent ?? playlistVideosContent)
      ?.firstWhereOrNull((e) => e['continuationItemRenderer'] != null)
      ?.get('continuationItemRenderer')
      ?.get('continuationEndpoint')
      ?.get('continuationCommand')
      ?.getT<String>('token');

  List<Map<String, dynamic>>? get playlistVideosContent =>
      root
          .get('contents')
          ?.get('twoColumnBrowseResultsRenderer')
          ?.getList('tabs')
          ?.firstOrNull
          ?.get('tabRenderer')
          ?.get('content')
          ?.get('sectionListRenderer')
          ?.getList('contents')
          ?.firstOrNull
          ?.get('itemSectionRenderer')
          ?.getList('contents')
          ?.firstOrNull
          ?.get('playlistVideoListRenderer')
          ?.getList('contents') ??
      root.getList('onResponseReceivedActions')?.firstOrNull?.get('appendContinuationItemsAction')?.getList('continuationItems');

  late final List<Map<String, dynamic>>? videosContent = root
          .get('contents')
          ?.get('twoColumnSearchResultsRenderer')
          ?.get('primaryContents')
          ?.get('sectionListRenderer')
          ?.getList('contents') ??
      root.getList('onResponseReceivedCommands')?.firstOrNull?.get('appendContinuationItemsAction')?.getList('continuationItems');

  List<_Video> get playlistVideos =>
      playlistVideosContent?.where((e) => e['playlistVideoRenderer'] != null).map((e) => _Video(e['playlistVideoRenderer'])).toList() ??
      const [];

  List<_Video> get videos =>
      videosContent?.firstOrNull
          ?.get('itemSectionRenderer')
          ?.getList('contents')
          ?.where((e) => e['videoRenderer'] != null)
          .map((e) => _Video(e))
          .toList() ??
      const [];
}

class _Video {
  // Json parsed map
  final Map<String, dynamic> root;

  _Video(this.root);

  String get id => root.getT<String>('videoId')!;

  String get author =>
      root.get('ownerText')?.getT<List<dynamic>>('runs')?.parseRuns() ??
      root.get('shortBylineText')?.getT<List<dynamic>>('runs')?.parseRuns() ??
      '';

  String get channelId =>
      root.get('ownerText')?.getList('runs')?.firstOrNull?.get('navigationEndpoint')?.get('browseEndpoint')?.getT<String>('browseId') ??
      root
          .get('shortBylineText')
          ?.getList('runs')
          ?.firstOrNull
          ?.get('navigationEndpoint')
          ?.get('browseEndpoint')
          ?.getT<String>('browseId') ??
      '';

  String get title => root.get('title')?.getList('runs')?.parseRuns() ?? '';

  String get description => root.getList('descriptionSnippet')?.parseRuns() ?? '';

  Duration? get duration => _stringToDuration(root.get('lengthText')?.getT<String>('simpleText'));

  int get viewCount => root.get('viewCountText')?.getT<String>('simpleText')?.parseInt() ?? 0;

  /// Format: HH:MM:SS
  static Duration? _stringToDuration(String? string) {
    if (string == null || string.trim().isEmpty) {
      return null;
    }

    var parts = string.split(':');
    assert(parts.length <= 3);

    if (parts.length == 1) {
      return Duration(seconds: int.parse(parts.first));
    }
    if (parts.length == 2) {
      return Duration(minutes: int.parse(parts.first), seconds: int.parse(parts[1]));
    }
    if (parts.length == 3) {
      return Duration(hours: int.parse(parts[0]), minutes: int.parse(parts[1]), seconds: int.parse(parts[2]));
    }
    throw Error();
  }
}