parse static method

Implementation

static GmcpEvent? parse(List<int> bytes) {
  // Basic validation: IAC SB 201 ... IAC SE
  // Minimum length: IAC SB 201 (3) + "A.B" (3) + IAC SE (2) = 8
  if (bytes.length < 5 ||
      bytes[0] != 255 ||
      bytes[1] != 250 ||
      bytes[2] != 201 ||
      bytes[bytes.length - 2] != 255 ||
      bytes[bytes.length - 1] != 240) {
    return null;
  }

  // Extract the payload (everything between option 201 and IAC SE)
  final payloadBytes = bytes.sublist(3, bytes.length - 2);
  if (payloadBytes.isEmpty) return null;

  final rawString = utf8.decode(payloadBytes).trim();
  if (rawString.isEmpty) return null;

  // GMCP format: Package.Message [JSON]
  // Example: Core.Welcome {"version": "1.0"}

  String packageMessage;
  Map<String, dynamic> data = {};

  final spaceIndex = rawString.indexOf(' ');
  if (spaceIndex != -1) {
    packageMessage = rawString.substring(0, spaceIndex);
    final jsonPart = rawString.substring(spaceIndex + 1).trim();
    if (jsonPart.isNotEmpty) {
      try {
        final decoded = jsonDecode(jsonPart);
        if (decoded is Map<String, dynamic>) {
          data = decoded;
        }
      } catch (_) {
        // If JSON is invalid, we return the event with empty data
        // or we could potentially throw an error depending on requirements.
        // For now, let's keep it robust.
      }
    }
  } else {
    packageMessage = rawString;
  }

  // Split Package.Message
  final dotIndex = packageMessage.lastIndexOf('.');
  String package;
  String message;

  if (dotIndex != -1) {
    package = packageMessage.substring(0, dotIndex);
    message = packageMessage.substring(dotIndex + 1);
  } else {
    package = '';
    message = packageMessage;
  }

  return GmcpEvent(package, message, data);
}