/* 独立主站字节测试：启动示例自己的Windows Net后端，仅连接127.0.0.1随机端口。
 * Node内置模块即可运行，不安装包、不复用待测ASDU编码器，不更改系统时钟。
 */
'use strict';
const assert = require('node:assert/strict');
const net = require('node:net');
const { spawn, spawnSync } = require('node:child_process');
const { once } = require('node:events');
const { setTimeout: delay } = require('node:timers/promises');
const executable = process.argv[2];
if (!executable) throw new Error('Usage: node slave_example_loopback_test.cjs <example.exe>');

class Master {
  constructor(socket) {
    this.socket = socket;
    this.buffer = Buffer.alloc(0);
    this.frames = [];
    this.waiters = [];
    this.ns = this.nr = 0;
    socket.on('data', data => {
      this.buffer = Buffer.concat([this.buffer, data]);
      try {
        while (this.buffer.length >= 2) {
          assert.equal(this.buffer[0], 0x68);
          assert(this.buffer[1] >= 4 && this.buffer[1] <= 253);
          const length = this.buffer[1] + 2;
          if (this.buffer.length < length) break;
          const frame = this.buffer.subarray(0, length);
          this.buffer = this.buffer.subarray(length);
          const waiter = this.waiters.shift();
          if (waiter) { clearTimeout(waiter.timer); waiter.resolve(frame); }
          else this.frames.push(frame);
        }
      } catch (error) { this.fail(error); socket.destroy(); }
    });
    socket.on('error', error => this.fail(error));
    socket.on('close', () => this.fail(new Error('Connection closed')));
  }
  fail(error) {
    this.error = error;
    for (const waiter of this.waiters.splice(0)) {
      clearTimeout(waiter.timer);
      waiter.reject(error);
    }
  }
  next() {
    if (this.frames.length) return Promise.resolve(this.frames.shift());
    if (this.error) return Promise.reject(this.error);
    return new Promise((resolve, reject) => {
      const waiter = { resolve, reject };
      waiter.timer = setTimeout(() => {
        this.waiters.splice(this.waiters.indexOf(waiter), 1);
        reject(new Error('Timed out waiting for an APDU'));
      }, 1500);
      this.waiters.push(waiter);
    });
  }
  async control(code, expected) {
    this.socket.write(Buffer.from([0x68, 4, code, 0, 0, 0]));
    for (let i = 0; i < 8; i++) {
      const frame = await this.next();
      if (frame[2] === 1) continue; // 主站I帧的S确认允许穿插。
      assert.deepEqual([...frame], [0x68, 4, expected, 0, 0, 0]);
      return;
    }
    throw new Error('Missing U-frame confirmation');
  }
  frame(payload) {
    const frame = Buffer.alloc(payload.length + 6);
    frame[0] = 0x68;
    frame[1] = payload.length + 4;
    frame.writeUInt16LE(this.ns++ << 1, 2);
    frame.writeUInt16LE(this.nr << 1, 4);
    Buffer.from(payload).copy(frame, 6);
    return frame;
  }
  async send(payload, fragmented = false) {
    const frame = this.frame(payload);
    if (fragmented) {
      this.socket.write(frame.subarray(0, 3));
      await delay(10);
      this.socket.write(frame.subarray(3));
    } else this.socket.write(frame);
  }
  async readASDU() {
    for (let i = 0; i < 8; i++) {
      const frame = await this.next();
      if (frame[2] === 1) continue;
      assert.equal(frame[2] & 1, 0);
      assert.equal(frame.readUInt16LE(2) >> 1, this.nr++);
      assert.equal(frame.readUInt16LE(4) >> 1, this.ns);
      const ack = Buffer.from([0x68, 4, 1, 0, 0, 0]);
      ack.writeUInt16LE(this.nr << 1, 4);
      this.socket.write(ack); // k=1，每帧ACK后服务才可继续发下一帧。
      return frame.subarray(6);
    }
    throw new Error('Missing I frame');
  }
  async close() {
    const closed = once(this.socket, 'close');
    this.socket.end();
    await closed;
  }
}

const signals = [0, 1, 0, 1, 1, 0, 1, 0];
const measures = [2300, 2310, 2290, 5000, -125, 0, 1234, 42];
const request = (oa, qoi = 20, ca = 7) => [100, 1, 0x86, oa, ca & 0xff, ca >> 8, 0, 0, 0, qoi];
const commandRequest = (type, oa, ioa, state, select, cot = 6, ca = 7) =>
  [type, 1, cot, oa, ca & 0xff, ca >> 8, ioa & 0xff, (ioa >> 8) & 0xff, ioa >> 16,
    state | 4 | (select ? 0x80 : 0)];

async function commandReply(master, payload, cot, negative = false) {
  await master.send(payload);
  const expected = [...payload]; expected[2] = (payload[2] & 0x80) | cot | (negative ? 0x40 : 0);
  assert.deepEqual([...(await master.readASDU())], expected);
}

async function commandExecute(master, type, oa, ioa, state, monitorIoa) {
  await commandReply(master, commandRequest(type, oa, ioa, state, true), 7);
  const execute = commandRequest(type, oa, ioa, state, false);
  await commandReply(master, execute, 7);
  assert.deepEqual([...(await master.readASDU())],
    [type === 45 ? 1 : 3, 1, 11, oa, 7, 0, monitorIoa & 0xff, (monitorIoa >> 8) & 0xff, 0, state]);
  const terminated = [...execute]; terminated[2] = 10;
  assert.deepEqual([...(await master.readASDU())], terminated);
}
const initialCounters = [120000, 345600, 7890, 0, 1, 65535, 2147483647, 42];
const counterRequest = (oa, qcc = 5, cot = 6, test = false, ca = 7) =>
  [101, 1, cot | (test ? 0x80 : 0), oa, ca & 0xff, ca >> 8, 0, 0, 0, qcc];
const clockRequest = (oa, cot = 6, test = false, ca = 7) =>
  [103, 1, cot | (test ? 0x80 : 0), oa, ca & 0xff, ca >> 8, 0, 0, 0, 0x39, 0x30, 34, 12, 28, 10, 26];
let counterSubmitted = 0, counterCompleted = 0;

async function readCounters(master, oa, qcc = 5, values = initialCounters, sequence = 0) {
  const group = qcc & 0x3f;
  const first = group === 2 ? 4 : 0, end = group === 1 ? 4 : 8;
  const count = 2 + (end - first) / 4;
  for (let frame = 0; frame < count; frame++) {
    const asdu = await master.readASDU();
    if (frame === 0 || frame === count - 1) {
      assert.deepEqual([...asdu], counterRequest(oa, qcc, frame === 0 ? 7 : 10));
    } else {
      assert.equal(asdu.length, 38);
      assert.deepEqual([...asdu.subarray(0, 6)], [15, 4, group === 5 ? 37 : 37 + group, oa, 7, 0]);
      for (let point = 0; point < 4; point++) {
        const offset = 6 + 8 * point, index = first + 4 * (frame - 1) + point;
        assert.equal(asdu.readUIntLE(offset, 3), 3001 + index);
        assert.equal(asdu.readInt32LE(offset + 3), values[index]);
        assert.equal(asdu[offset + 7], sequence);
      }
    }
  }
  counterSubmitted += count;
  counterCompleted++;
}

async function counterRead(master, oa, qcc = 5, values = initialCounters, sequence = 0, ca = 7) {
  await master.send(counterRequest(oa, qcc, 6, false, ca));
  await readCounters(master, oa, qcc, values, sequence);
}

async function counterReply(master, payload, cot, negative = false) {
  await master.send(payload);
  const expected = [...payload]; expected[2] = (payload[2] & 0x80) | cot | (negative ? 0x40 : 0);
  assert.deepEqual([...(await master.readASDU())], expected);
  counterSubmitted++;
  if (!negative) counterCompleted++;
}
async function totalCall(master, oa, fragmented = false, qoi = 20, ca = 7) {
  await master.send(request(oa, qoi, ca), fragmented);
  await readTotalCall(master, oa, qoi);
}

async function readTotalCall(master, oa, qoi = 20, busyRequests = []) {
  const original = request(oa, qoi);
  const count = qoi === 20 ? 6 : 4;
  const busyReplies = busyRequests.map(payload => {
    const expected = [...payload]; expected[2] = 0xc7;
    if (expected[4] === 0xff && expected[5] === 0xff) { expected[4] = 7; expected[5] = 0; }
    return Buffer.from(expected);
  });
  for (let f = 0; f < count || busyReplies.length;) {
    const asdu = await master.readASDU();
    if ((asdu[2] & 0x40) !== 0) {
      const index = busyReplies.findIndex(expected => expected.equals(asdu));
      assert(index >= 0, `Unexpected negative reply: ${asdu.toString('hex')}`);
      busyReplies.splice(index, 1);
      continue;
    }
    assert(f < count, 'Unexpected response after ACT_TERM');
    if (f === 0 || f === count - 1) {
      const expected = [...original];
      expected[2] = f === 0 ? 0x87 : 0x8a;
      assert.deepEqual([...asdu], expected);
    } else {
      const digital = qoi === 20 ? f < 3 : qoi === 21;
      const width = digital ? 4 : 6;
      const first = (qoi === 20 && !digital ? f - 3 : f - 1) * 4;
      assert.equal(asdu.length, 6 + width * 4);
      assert.deepEqual([...asdu.subarray(0, 6)], [digital ? 1 : 11, 4, 0x80 | qoi, oa, 7, 0]);
      for (let p = 0; p < 4; p++) {
        const offset = 6 + p * width;
        assert.equal(asdu.readUIntLE(offset, 3), (digital ? 1001 : 2001) + first + p);
        if (digital) assert.equal(asdu[offset + 3], signals[first + p]);
        else {
          assert.equal(asdu.readInt16LE(offset + 3), measures[first + p]);
          assert.equal(asdu[offset + 5], 0);
        }
      }
    }
    f++;
  }
}

async function main() {
  const help = spawnSync(executable, ['--help'], { windowsHide: true, encoding: 'utf8' });
  assert.ifError(help.error);
  assert.equal(help.status, 0, help.stderr);
  assert(help.stdout.includes('--run-ms'));
  assert(help.stdout.includes('--clock simulated|system'));
  assert(help.stdout.includes('Type45 IOA6001..6008'));
  const invalid = spawnSync(executable, ['--ca', '0'], { windowsHide: true, encoding: 'utf8' });
  assert.ifError(invalid.error);
  assert.equal(invalid.status, 1);
  const invalidClock = spawnSync(executable, ['--clock', 'invalid'], { windowsHide: true, encoding: 'utf8' });
  assert.ifError(invalidClock.error);
  assert.equal(invalidClock.status, 1);
  const child = spawn(executable, ['--port', '0', '--ca', '7', '--window', '1', '--run-ms', '12000'],
    { windowsHide: true, stdio: ['ignore', 'pipe', 'pipe'] });
  let output = '', errors = '';
  const sockets = [];
  child.stdout.on('data', data => { output += data.toString(); });
  child.stderr.on('data', data => { errors += data.toString(); });
  const exit = once(child, 'exit');
  const deadline = setTimeout(() => { child.kill(); }, 20000);
  try {
    const port = await new Promise((resolve, reject) => {
      const timer = setTimeout(() => reject(new Error(`No listening port: ${output} ${errors}`)), 2000);
      child.once('error', error => { clearTimeout(timer); reject(error); });
      child.stdout.on('data', () => {
        const match = output.match(/LISTEN 127\.0\.0\.1:(\d+) CA=7/);
        if (match) { clearTimeout(timer); resolve(Number(match[1])); }
      });
    });
    async function connect() {
      const socket = net.connect({ host: '127.0.0.1', port });
      sockets.push(socket);
      const master = new Master(socket);
      await once(socket, 'connect');
      await master.control(7, 0x0b);
      return master;
    }
    const master = await connect();
    // 一次write内的106延时获得和102读取逐条回显，k=1时第二条由HIGH等待首条ACK。
    const unsupportedBatch = [
      [106, 1, 0x86, 0x18, 7, 0, 0, 0, 0, 0x39, 0x30],
      [102, 1, 5, 0x19, 7, 0, 0xe9, 3, 0]
    ];
    master.socket.write(Buffer.concat(unsupportedBatch.map(payload => master.frame(payload))));
    for (const payload of unsupportedBatch) {
      const expected = [...payload]; expected[2] = (payload[2] & 0x80) | 0x40 | 44;
      assert.deepEqual([...(await master.readASDU())], expected);
    }
    // 默认模拟时钟：成功、TEST拒绝、错误COT及广播实际CA确认都保持请求时标原文。
    for (const [payload, cot, negative] of [
      [clockRequest(0x10), 7, false],
      [clockRequest(0x11, 6, true), 7, true],
      [clockRequest(0x12, 5), 45, true],
      [clockRequest(0x13, 6, false, 65535), 7, false]
    ]) {
      await master.send(payload);
      const expected = [...payload];
      expected[2] = (payload[2] & 0x80) | cot | (negative ? 0x40 : 0);
      expected[4] = 7; expected[5] = 0;
      assert.deepEqual([...(await master.readASDU())], expected);
    }
    // 同批103先保存执行任务，102当场兜底；Try确认必须等已提交的44之后发送。
    const clockBatch = clockRequest(0x14);
    const readBatch = [102, 1, 5, 0x15, 7, 0, 0xe9, 3, 0];
    master.socket.write(Buffer.concat([master.frame(clockBatch), master.frame(readBatch)]));
    const readRejected = [...readBatch]; readRejected[2] = 0x40 | 44;
    assert.deepEqual([...(await master.readASDU())], readRejected);
    const clockConfirmed = [...clockBatch]; clockConfirmed[2] = 7;
    assert.deepEqual([...(await master.readASDU())], clockConfirmed);
    // 遥控默认先选择；k=1验证确认、返回信息和终止逐帧交接，后续总召必须读到新值。
    await commandExecute(master, 45, 0x71, 6001, 1, 1001);
    signals[0] = 1;
    await commandExecute(master, 46, 0x72, 6103, 2, 1103);
    await commandReply(master, commandRequest(45, 0x73, 6002, 0, true), 7);
    await commandReply(master, commandRequest(45, 0x73, 6002, 1, true, 8), 9);
    await commandReply(master, commandRequest(45, 0x73, 6002, 0, false), 7, true);
    await commandReply(master, commandRequest(46, 0x74, 6101, 1, true, 6, 65535), 46, true);
    await commandReply(master, commandRequest(45, 0x75, 6999, 1, true), 47, true);
    const commandTest = commandRequest(45, 0x76, 6001, 0, true); commandTest[2] |= 0x80;
    await commandReply(master, commandTest, 7, true);
    await commandReply(master, commandRequest(47, 0x77, 6001, 1, false), 44, true);
    const timedCommand = commandRequest(58, 0x78, 6001, 0, true).concat([0, 0, 0, 0, 1, 1, 26]);
    await commandReply(master, timedCommand, 44, true);
    await counterRead(master, 0x20);
    await counterReply(master, counterRequest(0x21, 0x45), 7);
    await counterRead(master, 0x22, 5, initialCounters, 1);
    await counterRead(master, 0x23, 1, initialCounters, 1);
    await counterRead(master, 0x24, 2, initialCounters, 1);
    await counterReply(master, counterRequest(0x25, 3), 7, true);
    await counterReply(master, counterRequest(0x26, 4), 7, true);
    await counterReply(master, counterRequest(0x27, 5, 8), 45, true);
    // TEST requests must not freeze or clear real counters.
    await counterReply(master, counterRequest(0x28, 0x85, 6, true), 7, true);
    await counterRead(master, 0x29, 5, initialCounters, 1, 65535);
    await counterReply(master, counterRequest(0x2a, 0x85), 7);
    await counterRead(master, 0x2b, 5, initialCounters, 2);
    await counterReply(master, counterRequest(0x2c, 0x45), 7);
    const zeroCounters = initialCounters.map(() => 0);
    await counterRead(master, 0x2d, 5, zeroCounters, 3);
    await counterReply(master, counterRequest(0x2e, 0xc5), 7);
    await counterRead(master, 0x2f, 5, zeroCounters, 3);
    await totalCall(master, 0x5a, true);
    await totalCall(master, 0x5b, false, 21);
    await totalCall(master, 0x5c, false, 22);
    // 广播请求的确认、数据和终止均按实际本站CA=7核对。
    await totalCall(master, 0x5d, true, 20, 65535);
    await totalCall(master, 0x5e, false, 21, 65535);
    await totalCall(master, 0x5f, false, 22, 65535);
    // 连续提交不同QOI：只执行第一个，后两个否定；结束后由主站重发才执行。
    const burst = [[0x31, 22, 65535], [0x32, 20, 65535], [0x33, 21, 7]];
    master.socket.write(Buffer.concat(burst.map(([oa, qoi, ca]) => master.frame(request(oa, qoi, ca)))));
    await readTotalCall(master, 0x31, 22, burst.slice(1).map(([oa, qoi, ca]) => request(oa, qoi, ca)));
    for (const [oa, qoi] of burst.slice(1)) await totalCall(master, oa, false, qoi);
    for (const [index, value, cot] of [[4, 8, 46], [9, 37, 7], [9, 36, 7], [0, 200, 44]]) {
      const invalidRequest = request(0x55);
      invalidRequest[index] = value;
      if (index === 9) { invalidRequest[4] = invalidRequest[5] = 0xff; }
      await master.send(invalidRequest);
      const expected = [...invalidRequest];
      expected[2] = 0xc0 | cot;
      if (index === 9) { expected[4] = 7; expected[5] = 0; }
      assert.deepEqual([...(await master.readASDU())], expected);
    }
    // 同一接收批次的激活/撤销在驱动业务前按FIFO处理；随后重复撤销应否定确认。
    const activation = request(0x4a, 21, 65535);
    const deactivation = request(0x4a, 21); deactivation[2] = 0x88;
    master.socket.write(Buffer.concat([master.frame(activation), master.frame(deactivation)]));
    const deactCon = [...deactivation]; deactCon[2] = 0x89;
    assert.deepEqual([...(await master.readASDU())], deactCon);
    deactivation[4] = deactivation[5] = 0xff;
    await master.send(deactivation);
    deactCon[2] = 0xc9;
    assert.deepEqual([...(await master.readASDU())], deactCon);
    await master.control(0x13, 0x23);
    await master.control(7, 0x0b);
    // k=1: both instances must make progress, preserving their own response order.
    master.socket.write(Buffer.concat([master.frame(request(0x6b)), master.frame(counterRequest(0x60))]));
    const generalFrames = [], counterFrames = [];
    for (let index = 0; index < 10; index++) {
      const asdu = await master.readASDU();
      (asdu[0] === 101 || asdu[0] === 15 ? counterFrames : generalFrames).push(asdu);
    }
    assert.equal(generalFrames.length, 6);
    assert.equal(counterFrames.length, 4);
    await readTotalCall({ readASDU: async () => generalFrames.shift() }, 0x6b);
    await readCounters({ readASDU: async () => counterFrames.shift() }, 0x60, 5, zeroCounters, 3);
    await master.close();
    const next = await connect();
    await totalCall(next, 0x7c);
    await next.close();
    const [code] = await exit;
    assert.equal(code, 0, `${output}\n${errors}`);
    assert.match(output, /STOP submitted=67 gi_submitted=11 /);
    assert.match(output, /deactivated=1 timeouts=0/);
    assert.match(output, /negative_submitted=\d+ dropped_requests=0/);
    assert.match(output, new RegExp(`counter_submitted=${counterSubmitted} counter_completed=${counterCompleted}`));
    assert.match(output, /clock_executed=3 clock_synchronized=3 clock_submitted=5/);
    assert.match(output, /command_selected=3 command_executed=2 command_completed=2 command_submitted=\d+ command_returns=2/);
    assert.equal(errors, '');
    console.log('Slave example loopback: passed (real TCP, Type45/46 select/execute/return/termination, command cancel/TEST/address/unsupported types, changed GI value, batched 106+102 and 103+102, simulated clock, counters, k=1, STOP/START, reconnect, cleanup)');
  } finally {
    clearTimeout(deadline);
    for (const socket of sockets) socket.destroy();
    if (child.exitCode === null) child.kill();
  }
}

main().catch(error => { console.error(error); process.exitCode = 1; });