server.js

// ============================================================
// server.js — Dev server with static files + game state endpoint
// Usage: node server.js
// ============================================================

import { createServer } from 'http';
import { readFile, stat } from 'fs/promises';
import { join, extname } from 'path';
import { fileURLToPath } from 'url';

const __dirname = fileURLToPath(new URL('.', import.meta.url));
const PORT = 3000;

const MIME = {
  '.html': 'text/html',
  '.js':   'application/javascript',
  '.css':  'text/css',
  '.json': 'application/json',
  '.png':  'image/png',
  '.jpg':  'image/jpeg',
  '.svg':  'image/svg+xml',
  '.ico':  'image/x-icon',
};

let gameState = null;

const server = createServer(async (req, res) => {
  // --- API: game state ---
  if (req.url === '/api/state') {
    res.setHeader('Access-Control-Allow-Origin', '*');
    res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
    res.setHeader('Access-Control-Allow-Headers', 'Content-Type');

    if (req.method === 'OPTIONS') {
      res.writeHead(204);
      return res.end();
    }

    if (req.method === 'POST') {
      let body = '';
      req.on('data', chunk => { body += chunk; });
      req.on('end', () => {
        try {
          gameState = JSON.parse(body);
          res.writeHead(200, { 'Content-Type': 'application/json' });
          res.end('{"ok":true}');
        } catch {
          res.writeHead(400, { 'Content-Type': 'application/json' });
          res.end('{"error":"invalid json"}');
        }
      });
      return;
    }

    if (req.method === 'GET') {
      res.writeHead(200, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify(gameState, null, 2));
      return;
    }
  }

  // --- Static files ---
  let filePath = join(__dirname, req.url === '/' ? 'index.html' : req.url);

  try {
    const info = await stat(filePath);
    if (info.isDirectory()) filePath = join(filePath, 'index.html');

    const data = await readFile(filePath);
    const ext = extname(filePath);
    res.writeHead(200, { 'Content-Type': MIME[ext] || 'application/octet-stream' });
    res.end(data);
  } catch {
    res.writeHead(404, { 'Content-Type': 'text/plain' });
    res.end('404 Not Found');
  }
});

server.listen(PORT, () => {
  console.log(`Dev server: http://localhost:${PORT}`);
});