app-starlock/lib/talk/startChart/command/message_command.dart

import 'dart:convert';
import 'dart:typed_data';

import 'package:crc32_checksum/crc32_checksum.dart';
import 'package:star_lock/talk/startChart/constant/message_type_constant.dart';
import 'package:star_lock/talk/startChart/constant/payload_type_constant.dart';
import 'package:star_lock/talk/startChart/constant/protocol_flag_constant.dart';
import 'package:star_lock/talk/startChart/entity/scp_message.dart';
import 'package:star_lock/talk/startChart/proto/gateway_reset.pb.dart';

class MessageCommand {
  /// 客户端去中继上线命令
  static List<int> goOnlineRelay({
    required String FromPeerId,
    required String ToPeerId,
  }) {
    String serializedBytesString = ScpMessage(
      ProtocolFlag: ProtocolFlagConstant.scp01,
      MessageType: MessageTypeConstant.Req,
      MessageId: 1,
      SpTotal: 0,
      SpIndex: 0,
      FromPeerId: FromPeerId,
      ToPeerId: ToPeerId,
      Payload: 'hello',
      PayloadCRC: 55230,
      PayloadLength: 5,
      PayloadType: PayloadTypeConstant.goOnline,
    ).serialize();
    return _hexToBytes(serializedBytesString);
  }

  // 回声测试消息
  static List<int> echoMessage({
    required String ToPeerId,
    required String FromPeerId,
  }) {
    String payload = 'hello';
    ScpMessage message = ScpMessage(
      ProtocolFlag: ProtocolFlagConstant.scp01,
      MessageType: MessageTypeConstant.Req,
      MessageId: 1,
      SpTotal: 0,
      SpIndex: 0,
      FromPeerId: FromPeerId,
      ToPeerId: ToPeerId,
      Payload: payload,
      PayloadCRC: calculationCrc(_stringToUint8List(payload)),
      PayloadLength: payload.length,
      PayloadType: PayloadTypeConstant.echoTest,
    );
    String serializedBytesString = message.serialize();
    return _hexToBytes(serializedBytesString);
  }

  // 心跳消息
  static List<int> heartbeatMessage({
    required String FromPeerId,
    required String ToPeerId,
  }) {
    String payload = 'hello';
    ScpMessage message = ScpMessage(
      ProtocolFlag: ProtocolFlagConstant.scp01,
      MessageType: MessageTypeConstant.Req,
      MessageId: 1,
      SpTotal: 0,
      SpIndex: 0,
      FromPeerId: FromPeerId,
      ToPeerId: ToPeerId,
      Payload: payload,
      PayloadCRC: calculationCrc(_stringToUint8List(payload)),
      PayloadLength: payload.length,
      PayloadType: PayloadTypeConstant.heartbeat,
    );
    String serializedBytesString = message.serialize();
    return _hexToBytes(serializedBytesString);
  }

  // 网关初始化
  static List<int> gatewayResetMessage({
    required int gatewayId,
    required String FromPeerId,
    required String ToPeerId,
    required int time,
  }) {
    // 构建荷载
    final gatewayResetReq = GatewayResetReq(
      iD: gatewayId,
      time: time,
    );
    // 构建荷载长度
    final payload = gatewayResetReq.writeToBuffer();
    ScpMessage message = ScpMessage(
      ProtocolFlag: ProtocolFlagConstant.scp01,
      MessageType: MessageTypeConstant.Req,
      MessageId: 1,
      SpTotal: 0,
      SpIndex: 0,
      FromPeerId: FromPeerId,
      ToPeerId: ToPeerId,
      Payload: payload,
      PayloadCRC: calculationCrc(payload),
      PayloadLength: payload.length,
      PayloadType: PayloadTypeConstant.gatewayReset,
    );
    String serializedBytesString = message.serialize();
    return _hexToBytes(serializedBytesString);
  }

  // 通话保持消息
  static List<int> talkPingMessage({
    required String FromPeerId,
    required String ToPeerId,
  }) {
    String payload = 'hello';
    ScpMessage message = ScpMessage(
      ProtocolFlag: ProtocolFlagConstant.scp01,
      MessageType: MessageTypeConstant.Req,
      MessageId: 1,
      SpTotal: 0,
      SpIndex: 0,
      FromPeerId: FromPeerId,
      ToPeerId: ToPeerId,
      Payload: payload,
      PayloadCRC: calculationCrc(_stringToUint8List(payload)),
      PayloadLength: payload.length,
      PayloadType: PayloadTypeConstant.talkPing,
    );
    String serializedBytesString = message.serialize();
    return _hexToBytes(serializedBytesString);
  }

  // 辅助方法：将16进制字符串转换为字节列表
  static List<int> _hexToBytes(String hex) {
    final bytes = <int>[];
    for (int i = 0; i < hex.length; i += 2) {
      bytes.add(int.parse(hex.substring(i, i + 2), radix: 16));
    }
    return bytes;
  }

  static int calculationCrc(Uint8List uint8Payload) {
    // 使用自定义 CRC32 算法
    final int crc32Value = _crc32Uint16(uint8Payload);
    return crc32Value;
  }

  // 将字符串转换为 Uint8List
  static Uint8List _stringToUint8List(String input) {
    return Uint8List.fromList(utf8.encode(input));
  }

  // 自定义 CRC32 实现
  static int _crc32Uint16(Uint8List data) {
    const int polynomial = 0xD5828281;

    // 创建 CRC32 表
    final List<int> table = List<int>.generate(256, (i) {
      int crc = i;
      for (int j = 0; j < 8; j++) {
        if ((crc & 1) != 0) {
          crc = (crc >> 1) ^ polynomial;
        } else {
          crc >>= 1;
        }
      }
      return crc;
    });

    // 计算 CRC32 校验值
    int crc = 0xFFFFFFFF;
    for (final int byte in data) {
      crc = (crc >> 8) ^ table[(crc ^ byte) & 0xFF];
    }

    crc ^= 0xFFFFFFFF;

    // 返回 CRC32 的低 16 位
    return crc & 0xFFFF;
  }
}