app-starlock/lib/talk/startChart/entity/scp_message.dart

import 'dart:convert';
import 'package:crc32_checksum/crc32_checksum.dart';
import 'package:crypto/crypto.dart';
import 'package:star_lock/app_settings/app_settings.dart';

class ScpMessage {
  ScpMessage({
    this.ProtocolFlag,
    this.MessageType,
    this.MessageId,
    this.SpTotal,
    this.SpIndex,
    this.FromPeerId,
    this.ToPeerId,
    this.PayloadType,
    this.PayloadCRC,
    this.PayloadLength,
    this.Payload,
  });

  String? ProtocolFlag;
  int? MessageType;
  int? MessageId;
  int? SpTotal;
  int? SpIndex;
  String? FromPeerId;
  String? ToPeerId;
  int? PayloadType;
  int? PayloadCRC;
  int? PayloadLength;
  String? Payload;

  ScpMessage.fromJson(dynamic json) {
    ProtocolFlag = json['ProtocolFlag'];
    MessageType = json['MessageType'];
    MessageId = json['MessageId'];
    SpTotal = json['SpTotal'];
    SpIndex = json['SpIndex'];
    FromPeerId = json['FromPeerId'];
    ToPeerId = json['ToPeerId'];
    PayloadType = json['PayloadType'];
    PayloadCRC = json['PayloadCRC'];
    PayloadLength = json['PayloadLength'];
    Payload = json['Payload'];
  }

  Map<String, dynamic> toJson() {
    return {
      'ProtocolFlag': ProtocolFlag,
      'MessageType': MessageType,
      'MessageId': MessageId,
      'SpTotal': SpTotal,
      'SpIndex': SpIndex,
      'FromPeerId': FromPeerId,
      'ToPeerId': ToPeerId,
      'PayloadType': PayloadType,
      'PayloadCRC': PayloadCRC,
      'PayloadLength': PayloadLength,
      'Payload': Payload,
    };
  }

  String serialize() {
    final bytes = <int>[];

    // ProtocolFlag (4 bytes)
    if (ProtocolFlag != null) {
      bytes.addAll(utf8.encode(ProtocolFlag!));
    }

    // MessageType (1 byte)
    if (MessageType != null) {
      bytes.add(MessageType!);
    }

    // MessageId (2 bytes)
    if (MessageId != null) {
      final highByteMessageId = (MessageId! >> 8) & 0xFF;
      final lowByteMessageId = MessageId! & 0xFF;
      bytes.add(lowByteMessageId); // 交换位置
      bytes.add(highByteMessageId); // 交换位置
    }

    // SpTotal (1 byte)
    if (SpTotal != null) {
      bytes.add(SpTotal!);
    }

    // SpIndex (1 byte)
    if (SpIndex != null) {
      bytes.add(SpIndex!);
    }

    // FromPeerId (字符串，记录长度)
    if (FromPeerId != null) {
      bytes.addAll(utf8.encode(FromPeerId!));
    }

    // ToPeerId (字符串，假设长度固定为32字节)
    if (ToPeerId != null) {
      bytes.addAll(utf8.encode(ToPeerId!));
    }

    // PayloadType (2 bytes)
    if (PayloadType != null) {
      final highBytePayloadType = (PayloadType! >> 8) & 0xFF;
      final lowBytePayloadType = PayloadType! & 0xFF;
      bytes.add(lowBytePayloadType); // 交换位置
      bytes.add(highBytePayloadType); // 交换位置
    }

    // 计算 PayloadCRC (2 bytes)
    if (PayloadCRC != null) {
      final highBytePayloadCRC = (PayloadCRC! >> 8) & 0xFF;
      final lowBytePayloadCRC = PayloadCRC! & 0xFF;
      bytes.add(lowBytePayloadCRC); // 交换位置
      bytes.add(highBytePayloadCRC); // 交换位置
    }

    // PayloadLength (4 bytes)
    if (PayloadLength != null) {
      bytes.add(PayloadLength! & 0xFF);
      bytes.add((PayloadLength! >> 8) & 0xFF);
      bytes.add((PayloadLength! >> 16) & 0xFF);
      bytes.add((PayloadLength! >> 24) & 0xFF);
    }

    // Payload (字符串，转换为字节)
    if (Payload != null) {
      bytes.addAll(utf8.encode(Payload!));
    }

    // 转16进制字符串
    final bytesToHexString = bytesToHex(bytes);


    return bytesToHexString;
  }

  static String bytesToHex(List<int> bytes) {
    return bytes.map((byte) => byte.toRadixString(16).padLeft(2, '0')).join('');
  }
}