class FileDownloadProgress {
  int chunksDownloaded = 0;
  int chunksTotal = 1;
  bool complete = false;
  bool gotManifest = false;
  bool _interrupted = false;

  // we keep track of both an explicit interrupt flag (for when a request fails or is explicitly cancelled)
  set interrupted(isInterrupted) {
    this._interrupted = isInterrupted;
  }

  // but we have a fuzzy get which depends on lastUpdate, if the file isn't complete, but the last update was more
  // that 30 seconds ago, we consider this download as failed.
  get interrupted => _interrupted || (DateTime.now().difference(lastUpdate).abs().inSeconds > 30 && !complete);

  String? downloadedTo;
  DateTime? timeStart;
  DateTime? timeEnd;
  DateTime? requested;
  DateTime lastUpdate = DateTime.fromMillisecondsSinceEpoch(0);

  FileDownloadProgress(this.chunksTotal, this.timeStart);

  double progress() {
    return 1.0 * chunksDownloaded / chunksTotal;
  }

  void markUpdate() {
    lastUpdate = DateTime.now();
  }
}

String prettyBytes(int bytes) {
  if (bytes > 1000000000) {
    return (1.0 * bytes / 1000000000).toStringAsFixed(1) + " GB";
  } else if (bytes > 1000000) {
    return (1.0 * bytes / 1000000).toStringAsFixed(1) + " MB";
  } else if (bytes > 1000) {
    return (1.0 * bytes / 1000).toStringAsFixed(1) + " kB";
  } else {
    return bytes.toString() + " B";
  }
}