freezer/lib/api/download_manager/download_service.dart

import 'dart:io';

import 'package:dio/dio.dart';
import 'package:freezer/api/deezer.dart';
import 'package:freezer/api/deezer_audio.dart';
import 'package:freezer/api/download.dart';
import 'package:freezer/api/download_manager/service_interface.dart';
import 'package:freezer/main.dart';
import 'package:freezer/settings.dart';
import 'package:freezed_annotation/freezed_annotation.dart';
import 'package:path/path.dart';

part 'download_service.freezed.dart';
part 'download_service.g.dart';

class DownloadService {
  static const NOTIFICATION_ID = 6969;
  static const NOTIFICATION_CHANNEL_ID = "freezerdownloads";

  final ServiceInterface service;
  DownloadService(this.service);

  AudioQuality? _preferredQuality;
  AudioQuality? _downloadQuality;
  bool useGetURL = false;

  late String downloadFilename;

  late DeezerAPI _deezerAPI;

  void run() async {
    service.on('addDownloads', (event) {
      downloadTrack(DownloadInfo.fromJson(event!));
    });
    service.on('updateQuality', (event) {
      _preferredQuality = AudioQuality.values[event!['q']!];
    });
    service.on('updateCapabilities', (event) {
      final bool canStreamHQ = event!['canStreamHQ'];
      final bool canStreamLossless = event['canStreamLossless'];

      if (canStreamHQ || canStreamLossless) useGetURL = true;

      _downloadQuality = settings.maxQualityFor(
          _preferredQuality!, canStreamHQ, canStreamLossless);
    });
    service.on('updateSettings', (event) {
      if (event!['downloadFilename'] != null) {
        downloadFilename = event['downloadFilename'];
      }

      if (event['deezerLanguage'] != null) {
        _deezerAPI.deezerLanguage = event['deezerLanguage'];
      }
      if (event['deezerCountry'] != null) {
        _deezerAPI.deezerCountry = event['deezerCountry'];
      }
    });

    _deezerAPI = DeezerAPI(await getCookieJar());
    await _deezerAPI.authorize();

    service.send('ready');
  }

  void downloadTrack(DownloadInfo info) async {
    final trackId = info.trackId;
    final deezerAudio = DeezerAudio(
        deezerAPI: _deezerAPI,
        quality: _downloadQuality ?? AudioQuality.MP3_128,
        trackId: trackId);

    final track = await _deezerAPI.track(trackId);
    final file = File(join(
        info.path!,
        downloadFilename
            .replaceAll('%artist%', track.artists?.join(',') ?? '')
            .replaceAll('%title%', track.title!)));
    print('downloading to ${file.path}');
    final Uri uri;
    if (useGetURL) {
      // TODO: use pipe API to get track token!
      final res = await deezerAudio.getUrl(
          track.trackToken!, track.trackTokenExpiration!);
      uri = res!.$1;
    } else {
      final res = await deezerAudio.fallback(
          md5origin: track.playbackDetails![0],
          mediaVersion: track.playbackDetails![1]);
      uri = res.uri;
    }

    // download url and decrypt
    final req = await _deezerAPI.dio.get(uri.toString(),
        options: Options(responseType: ResponseType.bytes));
    final stream =
        DeezerAudio.decryptionStream(req.data, start: 0, trackId: trackId);
    final fWrite = file.openWrite();
    await stream.pipe(fWrite);
    print('download complete!');
  }
}

@freezed
class DownloadInfo with _$DownloadInfo {
  const factory DownloadInfo({required String trackId, String? path}) =
      _DownloadInfo;
  factory DownloadInfo.fromJson(Map<String, dynamic> json) =>
      _$DownloadInfoFromJson(json);
}