startDownload method

@override Future<String> startDownload({ required String fileUrl, required String savePath, Map<String, String>? headers, })

Starts a file download operation in the background.

The download continues even if the app moves to the background. Progress can be tracked using getDownloadProgress.

Parameters:

• fileUrl: The URL of the file to download
• savePath: Local path where the downloaded file should be saved
• headers: Optional HTTP headers to include in the request

Returns a task ID string that can be used to track progress or cancel the task.

Throws an Exception if the download fails to start.

Implementation

@override
Future<String> startDownload({
  required String fileUrl,
  required String savePath,
  Map<String, String>? headers,
}) async {
  final taskId = DateTime.now().toIso8601String();
  _taskDetails[taskId] = {
    'type': 'download',
    'url': fileUrl,
    'path': savePath,
    'createdAt': DateTime.now().toIso8601String(),
  };
  _progressControllers[taskId] = StreamController<double>();
  _currentProgress[taskId] = 0.0;

  await _enqueueOperation(() {
    // Simulate download progress
    Timer.periodic(const Duration(milliseconds: 100), (timer) {
      final controller = _progressControllers[taskId];
      if (controller == null || controller.isClosed) {
        timer.cancel();
        _operationComplete();
        return;
      }

      double progress = 0.0;
      controller.addStream(Stream.periodic(
        const Duration(milliseconds: 100),
        (count) {
          progress = (count + 1) / 10;
          _updateProgress(taskId, progress);
          if (progress >= 1.0) {
            timer.cancel();
            _completedTasks[taskId] = true;
            _createMockFile(savePath);
            _operationComplete();
          }
          return progress;
        },
      ).take(10));
    });
  });

  return taskId;
}