fromPacket static method

TePacket fromPacket(String raw)

fromPacket creates a TePacket from a string packet in the format of Layrz Protocol v3.

Implementation

static TePacket fromPacket(String raw) {
  if (!raw.startsWith('<Te>') || !raw.endsWith('</Te>')) {
    throw ParseException('Invalid identification packet, should be <Te>...</Te>');
  }

  final parts = raw.substring(4, raw.length - 5).split(';');
  if (parts.length != 6) {
    throw MalformedException('Invalid packet parts, should have 6 parts');
  }

  int? receivedCrc = int.tryParse(parts.last, radix: 16);
  int? calculatedCrc = calculateCrc("${parts.sublist(0, 5).join(';')};".codeUnits);

  if (receivedCrc != calculatedCrc) {
    throw CrcException('Invalid CRC, received: $receivedCrc, calculated: $calculatedCrc');
  }

  DateTime timestamp;
  try {
    timestamp = DateTime.fromMillisecondsSinceEpoch(int.parse(parts[0]) * 1000, isUtc: true);
  } catch (e) {
    throw MalformedException('Invalid timestamp');
  }

  double distanceTraveled;
  try {
    distanceTraveled = double.parse(parts[2]);
  } catch (e) {
    throw MalformedException('Invalid distance traveled ${parts[2]}');
  }

  double maxSpeed;
  try {
    maxSpeed = double.parse(parts[3]);
  } catch (e) {
    throw MalformedException('Invalid max speed');
  }

  Duration duration;
  try {
    duration = Duration(seconds: int.parse(parts[4]));
  } catch (e) {
    throw MalformedException('Invalid duration');
  }

  return TePacket(
    timestamp: timestamp,
    distanceTraveled: distanceTraveled,
    maxSpeed: maxSpeed,
    duration: duration,
    tripId: parts[1],
  );
}