import { spawn } from 'node:child_process';
import http from 'node:http';
import net from 'node:net';
import { fileURLToPath } from 'node:url';

import { resolveAgcDevEndpoint, withAgcDevEndpointEnv } from './dev-port.mjs';

const appRoot = fileURLToPath(new URL('..', import.meta.url));
const endpoint = await resolveAgcDevEndpoint();
const { host, port, url: devUrl } = endpoint;

function readExistingServer() {
  return new Promise((resolve) => {
    const request = http.get(
      {
        host,
        port,
        path: '/',
        timeout: 1000,
      },
      (response) => {
        let body = '';
        response.setEncoding('utf8');
        response.on('data', (chunk) => {
          if (body.length < 4096) {
            body += chunk;
          }
        });
        response.on('end', () => {
          resolve({
            statusCode: response.statusCode ?? 0,
            body,
          });
        });
      },
    );
    request.on('timeout', () => {
      request.destroy();
      resolve(null);
    });
    request.on('error', () => resolve(null));
  });
}

function isAiGameCreatorServer(response) {
  return (
    response &&
    response.statusCode >= 200 &&
    response.statusCode < 500 &&
    response.body.includes('<title>陶泥儿</title>') &&
    response.body.includes('/src/main.tsx')
  );
}

function isPortListening() {
  return new Promise((resolve) => {
    const socket = net.connect({ host, port });
    socket.once('connect', () => {
      socket.destroy();
      resolve(true);
    });
    socket.once('error', () => resolve(false));
    socket.setTimeout(1000, () => {
      socket.destroy();
      resolve(true);
    });
  });
}

const existing = await readExistingServer();
if (existing) {
  if (isAiGameCreatorServer(existing)) {
    console.error(
      `[ai-game-creator-shell] ${devUrl} is already running but cannot be safely reused. Stop that process before starting the dev server.`,
    );
    process.exit(1);
  }
  console.error(
    `[ai-game-creator-shell] ${devUrl} is already in use by another server. Stop that process before starting Tauri dev.`,
  );
  process.exit(1);
}

if (await isPortListening()) {
  console.error(
    `[ai-game-creator-shell] ${devUrl} is already in use by a non-HTTP or unrecognized server. Stop that process before starting Tauri dev.`,
  );
  process.exit(1);
}

const npm = process.platform === 'win32' ? 'npm.cmd' : 'npm';
const child = spawn(
  npm,
  [
    '--prefix',
    '../..',
    'exec',
    'vite',
    '--',
    '--config',
    'vite.config.ts',
    '--port',
    String(endpoint.port),
  ],
  {
    cwd: appRoot,
    env: withAgcDevEndpointEnv(endpoint),
    stdio: 'inherit',
    // Node 18.20+/20+/24 on Windows rejects spawning .cmd (npm.cmd) without a shell (EINVAL).
    shell: true,
  },
);

for (const signal of ['SIGINT', 'SIGTERM']) {
  process.on(signal, () => {
    child.kill(signal);
  });
}

child.on('exit', (code, signal) => {
  if (signal) {
    process.exit(1);
  }
  process.exit(code ?? 0);
});