const net = require('net');

// ====== 配置区（设备客户端模拟）======
const HOST = '127.0.0.1';  // 服务端地址（联调用本机）
const PORT = 8234;         // 服务端端口
// ======================================

// 指令（来自服务端）
const ACTIVATE_CMD_HEX = '16 2f 40 31 04 03';
const GET_DATA_CMD_HEX = '16 31 3f 43 44 04 03';

// 设备回传固定数据帧（收到获取数据指令后返回）
const RESPONSE_HEX = '16 31 5F 43 44 02 6B 42 56 2B 30 30 36 41 2D 30 30 32 55 2B 30 38 37 42 30 30 30 30 53 30 33 36 35 54 30 33 32 35 43 30 31 30 35 52 30 30 30 30 47 30 30 30 30 50 30 30 30 30 48 30 30 30 30 46 35 58 30 30 30 30 4D 30 30 30 30 30 30 49 30 30 30 4C 34 39 35 33 52 34 37 31 36 32 30 5A 2B 30 30 30 4E 31 34 30 30 42 2B 30 51 30 30 30 59 30 30 30 49 37 56 43 41 30 59 38 32 53 30 30 30 50 30 30 52 30 30 30 42 30 30 30 30 56 30 30 30 30 42 32 33 37 33 37 38 30 53 32 45 31 46 42 38 37 33 37 31 38 31 46 31 46 30 30 30 59 30 30 30 30 35 35 06 03';

// ===== 工具函数 =====
function hexToBuffer(hexStr) {
  const hex = hexStr.replace(/\s+/g, '');
  const bytes = [];
  for (let i = 0; i < hex.length; i += 2) {
    bytes.push(parseInt(hex.substr(i, 2), 16));
  }
  return Buffer.from(bytes);
}

function bufferToHex(buf) {
  return buf.toString('hex').replace(/(.{2})/g, '$1 ').trim().toUpperCase();
}

const ACTIVATE_CMD = hexToBuffer(ACTIVATE_CMD_HEX);
const GET_DATA_CMD = hexToBuffer(GET_DATA_CMD_HEX);
const RESPONSE_BUF = hexToBuffer(RESPONSE_HEX);

let socket;
let rxBuffer = Buffer.alloc(0);

function initClient() {
  socket = new net.Socket();

  socket.on('connect', () => {
    console.log(`✅ 设备客户端已连接到服务端: ${HOST}:${PORT}`);
    socket.setKeepAlive(true, 10000);
  });

  socket.on('data', (chunk) => {
    rxBuffer = Buffer.concat([rxBuffer, chunk]);
    console.log(`📥 收到服务端数据 (${chunk.length} bytes): ${bufferToHex(chunk)}`);

    let progressed = true;
    while (progressed) {
      progressed = false;

      const idxActivate = rxBuffer.indexOf(ACTIVATE_CMD);
      if (idxActivate !== -1) {
        // 收到激活指令：不返回，仅移除
        console.log('   🔸 收到 激活指令（设备端不回应）');
        rxBuffer = Buffer.concat([
          rxBuffer.slice(0, idxActivate),
          rxBuffer.slice(idxActivate + ACTIVATE_CMD.length)
        ]);
        progressed = true;
        continue;
      }

      const idxGetData = rxBuffer.indexOf(GET_DATA_CMD);
      if (idxGetData !== -1) {
        console.log('   🔹 收到 获取治疗数据指令（设备端回传数据帧）');
        rxBuffer = Buffer.concat([
          rxBuffer.slice(0, idxGetData),
          rxBuffer.slice(idxGetData + GET_DATA_CMD.length)
        ]);
        socket.write(RESPONSE_BUF);
        console.log(`📤 已发送数据帧 (${RESPONSE_BUF.length} bytes)`);
        progressed = true;
        continue;
      }
    }

    if (rxBuffer.length > 1024 * 1024) {
      console.warn('⚠️ 接收缓冲区异常增长，清空');
      rxBuffer = Buffer.alloc(0);
    }
  });

  socket.on('error', (err) => {
    console.error('❌ 设备客户端错误:', err.message);
  });

  socket.on('close', () => {
    console.log('🔌 与服务端连接断开，3秒后重连...');
    setTimeout(connectServer, 3000);
  });

  connectServer();
}

function connectServer() {
  try {
    console.log(`🔗 正在连接服务端 ${HOST}:${PORT} ...`);
    socket.connect(PORT, HOST);
  } catch (err) {
    console.error('❌ 连接失败:', err.message);
    setTimeout(connectServer, 3000);
  }
}

function shutdown() {
  console.log('\n🛑 设备客户端正在关闭...');
  if (socket) socket.destroy();
  process.exit(0);
}

console.log('🩺 Fresenius 4008S 设备客户端模拟器启动');
console.log(`🌐 目标服务端: ${HOST}:${PORT}`);
initClient();

process.on('SIGINT', shutdown);
process.on('SIGTERM', shutdown);