class HeartbeatResponse {
  int? statusCode;
  int? nextPingTime;
  String? clientAddr;

  HeartbeatResponse({
    this.statusCode,
    this.nextPingTime,
    this.clientAddr,
  });

  factory HeartbeatResponse.fromBytes(List<int> bytes) {
    final message = HeartbeatResponse();
    int offset = 0;

    // 检查是否有足够的数据来解析状态码
    if (bytes.length < 1) {
      throw FormatException("Insufficient data for HeartbeatResponse");
    }

    // 解析状态码 (1 byte)
    message.statusCode = bytes[offset];
    offset += 1;

    // 检查是否有足够的数据来解析 nextPingTime
    if (bytes.length < offset + 2) {
      throw FormatException("Insufficient data for nextPingTime");
    }

    // 解析 nextPingTime (2 bytes, little-endian)
    message.nextPingTime = (bytes[offset + 1] << 8) | bytes[offset];
    offset += 2;

    // 解析 clientAddr (null-terminated string)
    final clientAddrBytes = <int>[];
    while (offset < bytes.length && bytes[offset] != 0) {
      clientAddrBytes.add(bytes[offset]);
      offset++;
    }

    // 跳过 null terminator
    if (offset < bytes.length && bytes[offset] == 0) {
      offset++;
    }

    message.clientAddr = String.fromCharCodes(clientAddrBytes);

    return message;
  }

  @override
  String toString() {
    return 'HeartbeatResponse{statusCode: $statusCode, nextPingTime: $nextPingTime, clientAddr: $clientAddr}';
  }
}