/**
 * Prepare local dev: free backend port and ensure MySQL is reachable.
 * Runs automatically via npm "predev" before `npm run dev`.
 */
import { execSync } from 'node:child_process';
import net from 'node:net';
import { platform } from 'node:os';
import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';

const MYSQL_PORT = 3306;
const BACKEND_LISTEN_PORT = 3001;
const FRONTEND_PORT = 5173;

const __dirname = dirname(fileURLToPath(import.meta.url));
const rootDir = join(__dirname, '..');
const backendDir = join(rootDir, 'backend');

function log(msg) {
  console.log(`[prepare-dev] ${msg}`);
}

function isPortOpen(port, host = '127.0.0.1') {
  return new Promise((resolve) => {
    const socket = net.createConnection({ port, host }, () => {
      socket.destroy();
      resolve(true);
    });
    socket.on('error', () => resolve(false));
    socket.setTimeout(1500, () => {
      socket.destroy();
      resolve(false);
    });
  });
}

function freePort(port) {
  if (platform() === 'win32') {
    try {
      const out = execSync(`netstat -ano | findstr :${port}`, { encoding: 'utf8' });
      const pids = new Set();
      for (const line of out.split('\n')) {
        if (!line.includes('LISTENING')) continue;
        const parts = line.trim().split(/\s+/);
        const pid = parts[parts.length - 1];
        if (pid && pid !== '0') pids.add(pid);
      }
      for (const pid of pids) {
        log(`Stopping process ${pid} on port ${port}`);
        execSync(`taskkill /F /PID ${pid}`, { stdio: 'ignore' });
      }
    } catch {
      // nothing listening
    }
    return;
  }

  try {
    execSync(`lsof -ti:${port} | xargs kill -9 2>/dev/null`, { stdio: 'ignore', shell: true });
  } catch {
    // nothing listening
  }
}

async function ensureMysql() {
  if (await isPortOpen(MYSQL_PORT)) {
    log(`MySQL is reachable on port ${MYSQL_PORT}`);
    return;
  }

  log(`MySQL not reachable on port ${MYSQL_PORT}; starting Docker Compose...`);
  try {
    execSync('docker compose -f docker-compose.dev.yml up -d', {
      cwd: backendDir,
      stdio: 'inherit',
    });
  } catch {
    console.error(
      '[prepare-dev] ERROR: MySQL is not running. Start it with:\n' +
        '  cd backend && docker compose -f docker-compose.dev.yml up -d',
    );
    process.exit(1);
  }

  for (let i = 0; i < 30; i += 1) {
    if (await isPortOpen(MYSQL_PORT)) {
      log('MySQL is ready');
      return;
    }
    await new Promise((r) => setTimeout(r, 1000));
  }

  console.error('[prepare-dev] ERROR: MySQL did not become ready in time.');
  process.exit(1);
}

freePort(BACKEND_LISTEN_PORT);
freePort(FRONTEND_PORT);
await ensureMysql();
log(`Ready — backend will listen on port ${BACKEND_LISTEN_PORT}`);