import 'package:xml/xml.dart' as xml;

import '../../extensions/helpers_extension.dart';
import '../../reverse_engineering/responses/responses.dart'
    hide ClosedCaption, ClosedCaptionPart, ClosedCaptionTrack;
import '../../reverse_engineering/youtube_http_client.dart';
import '../videos.dart';
import 'closed_caption.dart';
import 'closed_caption_manifest.dart';
import 'closed_caption_part.dart';
import 'closed_caption_track.dart';
import 'closed_caption_track_info.dart';
import 'language.dart';

/// Queries related to closed captions of YouTube videos.
class ClosedCaptionClient {
  final YoutubeHttpClient _httpClient;

  /// Initializes an instance of [ClosedCaptionClient]
  ClosedCaptionClient(this._httpClient);

  /// Gets the manifest that contains information
  /// about available closed caption tracks in the specified video.
  Future<ClosedCaptionManifest> getManifest(dynamic videoId,
      {bool autoGenerated = false}) async {
    videoId = VideoId.fromString(videoId);
    var tracks = <ClosedCaptionTrackInfo>[];
    if (!autoGenerated) {
      var subList = await _httpClient.get(
          'https://video.google.com/timedtext?hl=en&type=list&v=${videoId.value}',
          validate: true);
      // ignore: deprecated_member_use
      var content = xml.parse(subList.body);

      var langList = <String>[];
      for (var track in content.findAllElements('track')) {
        var lang = track.getAttribute('lang_code');
        if (langList.contains(lang)) {
          continue;
        }
        langList.add(lang);
        for (var ext in ClosedCaptionFormat.values) {
          tracks.add(ClosedCaptionTrackInfo(
              Uri.parse('https://www.youtube.com/api/timedtext')
                  .replaceQueryParameters({
                'lang': lang,
                'v': videoId.value,
                'fmt': ext.formatCode,
                'name': track.getAttribute('name'),
              }),
              Language(lang, track.getAttribute('lang_translated')),
              format: ext));
        }
      }
      if (langList.isEmpty) {
        return ClosedCaptionManifest([]);
      }
      return ClosedCaptionManifest(tracks);
    } else {
      var videoInfoResponse =
          await VideoInfoResponse.get(_httpClient, videoId.value);
      var playerResponse = videoInfoResponse.playerResponse;

      for (var track in playerResponse.closedCaptionTrack) {
        for (var ext in ClosedCaptionFormat.values) {
          tracks.add(ClosedCaptionTrackInfo(
              Uri.parse(track.url)
                  .replaceQueryParameters({'fmt': ext.formatCode}),
              Language(track.languageCode, track.languageName),
              isAutoGenerated: track.autoGenerated,
              format: ext));
        }
      }
    }
    return ClosedCaptionManifest(tracks);
  }

  /// Gets the actual closed caption track which is
  /// identified by the specified metadata.
  Future<ClosedCaptionTrack> get(ClosedCaptionTrackInfo trackInfo) async {
    var response = await ClosedCaptionTrackResponse.get(
        _httpClient, trackInfo.url);

    var captions = response.closedCaptions
        .where((e) => !e.text.isNullOrWhiteSpace)
        .map((e) => ClosedCaption(e.text, e.offset, e.duration,
            e.getParts().map((f) => ClosedCaptionPart(f.text, f.offset))));
    return ClosedCaptionTrack(captions);
  }

  /// Returns the subtitles as a string.
  Future<String> getSubTitles(ClosedCaptionTrackInfo trackInfo) =>
      _httpClient.getString(trackInfo.url);
}