import assert from 'node:assert/strict';
import { readFile } from 'node:fs/promises';
import test from 'node:test';
import { getKnownHostsLine, mergeEnv, validateEnrollmentResponse } from '../scripts/remote-access-common.mjs';
import { buildSshArgs, computeTunnelRetryDelay } from '../scripts/start-remote.mjs';

const enrollment = {
  installation_id: 'dev-123',
  ssh: {
    host: '203.0.113.10',
    port: 22,
    user: 'tunnel',
    certificate: 'ssh-ed25519-cert-v01@openssh.com AAAATEST cert',
    host_key: 'ssh-ed25519 AAAATEST host',
  },
  database: {
    name: 'system_db',
    username: 'client_123',
    password: 'a password with # symbols',
  },
  redis: {
    host: 'redis.example.test',
    port: 6380,
    username: 'cangku_1234567890abcdef',
    password: 'redis secret',
    db: 0,
    tls: true,
    tls_server_name: 'redis.example.test',
  },
  application_admin: {
    username: 'dev_123',
    password: 'one-time-password',
  },
};

test('validates complete enrollment responses', () => {
  assert.equal(validateEnrollmentResponse(enrollment), enrollment);
  assert.throws(
    () => validateEnrollmentResponse({ ...enrollment, database: { ...enrollment.database, password: '' } }),
    /database\.password/u
  );
});

test('builds an SSH tunnel only for the system database', () => {
  const args = buildSshArgs({
    localDatabasePort: 13307,
    ssh: {
      host: 'example.test',
      port: 50232,
      user: 'cangku-tunnel',
      remoteDatabaseHost: '127.0.0.1',
      remoteDatabasePort: 3307,
    },
  });
  assert.ok(args.includes('127.0.0.1:13307:127.0.0.1:3307'));
  assert.equal(args.some((value) => String(value).includes(':6380')), false);
});

test('merges environment values without losing unrelated settings', () => {
  const result = mergeEnv('KEEP=yes\nLOCAL_DB_HOST=old\n', {
    LOCAL_DB_HOST: '127.0.0.1',
    LOCAL_DB_PASSWORD: 'secret # value',
  });
  assert.match(result, /^KEEP=yes$/mu);
  assert.match(result, /^LOCAL_DB_HOST=127\.0\.0\.1$/mu);
  assert.match(result, /^LOCAL_DB_PASSWORD="secret # value"$/mu);
});

test('pins standard and non-standard SSH host targets', () => {
  assert.equal(getKnownHostsLine('example.test', 22, 'ssh-ed25519 KEY'), 'example.test ssh-ed25519 KEY\n');
  assert.equal(getKnownHostsLine('example.test', 2222, 'ssh-ed25519 KEY'), '[example.test]:2222 ssh-ed25519 KEY\n');
});

// ─────────────────────────────────────────────────────────────────────────────
// 隧道自愈（根治远端 RST 导致「网站打不开」）
//
// 旧行为：隧道进程 exit → stopChildren()，把后端 + 前端一起杀掉，于是每一次远端
//         RST 都升级成一次整栈不可用，还得靠外部守护清残留、整树重启。
// 新行为：隧道 exit → 只重连隧道本身，应用进程不受影响。
// ─────────────────────────────────────────────────────────────────────────────

const tunnelConfig = {
  localDatabasePort: 13307,
  ssh: {
    host: 'example.test',
    port: 50232,
    user: 'cangku-tunnel',
    remoteDatabaseHost: '127.0.0.1',
    remoteDatabasePort: 3307,
  },
};

test('tunnel keepalive: 更快发现死连接，且不会在 connect 阶段无限等待', () => {
  const flags = new Set(buildSshArgs(tunnelConfig));
  // ExitOnForwardFailure 缺失会出现最阴险的故障：进程活着、端口却没绑上（「静默成功」）
  assert.ok(flags.has('ExitOnForwardFailure=yes'), '必须保留 ExitOnForwardFailure=yes');
  assert.ok(flags.has('ServerAliveInterval=15'), '探活间隔应为 15s，以便更快发现被 RST 的连接');
  assert.ok(flags.has('ServerAliveCountMax=3'));
  assert.ok(flags.has('TCPKeepAlive=yes'), '需要内核层保活兜底');
  assert.ok(flags.has('ConnectTimeout=10'), '连不上时应快速失败，交给退避重连而不是干等');
});

test('tunnel retry backoff: 1s 起指数增长，封顶 30s 且不会溢出', () => {
  assert.equal(computeTunnelRetryDelay(0), 1000);
  assert.equal(computeTunnelRetryDelay(1), 2000);
  assert.equal(computeTunnelRetryDelay(2), 4000);
  assert.equal(computeTunnelRetryDelay(4), 16000);
  assert.equal(computeTunnelRetryDelay(5), 30000);
  // 长期不可用时 attempt 会一路增长，必须封顶而不是算成 Infinity / 0
  assert.equal(computeTunnelRetryDelay(200), 30000);
  assert.ok(Number.isFinite(computeTunnelRetryDelay(2000)));
});

test('防腐化：隧道自愈循环不得停止后端/前端进程', async () => {
  const source = await readFile(new URL('../scripts/start-remote.mjs', import.meta.url), 'utf8');
  const start = source.indexOf('const superviseTunnel = async () => {');
  const end = source.indexOf('const startTunnelSupervisor = () => {');
  assert.ok(start > 0 && end > start, '未定位到 superviseTunnel 实现');

  const body = source.slice(start, end);
  assert.equal(
    body.includes('stopChildren()'),
    false,
    '隧道重连不得牵连后端/前端 —— 否则又回到「隧道一断，整个开发栈陪葬」'
  );
  assert.ok(
    body.includes('await sleep('),
    '隧道退出后必须先等待再重连，避免 RST 时疯狂重连打爆对端'
  );
});