const http = require('http');
const fs = require('fs');
const path = require('path');

const ROOT = __dirname;
const DATA_FILE = path.join(ROOT, 'data.json');
const PORT = Number(process.env.PORT) || 8080;

const TYPES = {
  '.html': 'text/html; charset=utf-8',
  '.js': 'text/javascript; charset=utf-8',
  '.json': 'application/json; charset=utf-8',
  '.css': 'text/css; charset=utf-8',
  '.svg': 'image/svg+xml',
};

function send(res, status, body, type = 'text/plain; charset=utf-8') {
  res.writeHead(status, { 'Content-Type': type });
  res.end(body);
}

function readBody(req) {
  return new Promise((resolve, reject) => {
    let body = '';
    req.on('data', (chunk) => {
      body += chunk;
      if (body.length > 2_000_000) {
        req.destroy();
        reject(new Error('Request body too large'));
      }
    });
    req.on('end', () => resolve(body));
    req.on('error', reject);
  });
}

const server = http.createServer(async (req, res) => {
  try {
    const url = new URL(req.url, `http://${req.headers.host}`);

    if (req.method === 'POST' && url.pathname === '/api/data') {
      const body = await readBody(req);
      const data = JSON.parse(body);

      if (!data || typeof data !== 'object' || !data.surcharges || !Array.isArray(data.history)) {
        return send(res, 400, JSON.stringify({ error: 'Invalid data format' }), 'application/json; charset=utf-8');
      }

      fs.writeFileSync(DATA_FILE, JSON.stringify(data, null, 2) + '\n');
      return send(res, 200, JSON.stringify({ ok: true }), 'application/json; charset=utf-8');
    }

    if (req.method !== 'GET' && req.method !== 'HEAD') {
      return send(res, 405, 'Method not allowed');
    }

    const requestPath = url.pathname === '/' ? '/index.html' : url.pathname;
    const filePath = path.normalize(path.join(ROOT, requestPath));

    if (!filePath.startsWith(ROOT)) return send(res, 403, 'Forbidden');
    if (!fs.existsSync(filePath) || !fs.statSync(filePath).isFile()) return send(res, 404, 'Not found');

    const type = TYPES[path.extname(filePath)] || 'application/octet-stream';
    res.writeHead(200, { 'Content-Type': type });
    if (req.method === 'HEAD') return res.end();
    fs.createReadStream(filePath).pipe(res);
  } catch (err) {
    console.error(err);
    send(res, 500, JSON.stringify({ error: err.message }), 'application/json; charset=utf-8');
  }
});

server.listen(PORT, () => {
  console.log(`AZ INTEC Index läuft auf http://localhost:${PORT}`);
});