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

const DIST = '/home/pan/silk/web/dist';
const PORT = 5174;

const MIME = {
  '.html': 'text/html; charset=utf-8',
  '.js': 'application/javascript; charset=utf-8',
  '.css': 'text/css; charset=utf-8',
  '.json': 'application/json; charset=utf-8',
  '.png': 'image/png',
  '.svg': 'image/svg+xml',
  '.ico': 'image/x-icon',
  '.woff': 'font/woff',
  '.woff2': 'font/woff2',
};

const server = http.createServer((req, res) => {
  console.log(`${req.method} ${req.url}`);

  // API proxy to NestJS
  if (req.url.startsWith('/api')) {
    const options = {
      hostname: '127.0.0.1',
      port: 3000,
      path: req.url,
      method: req.method,
      headers: { ...req.headers, host: 'localhost:3000' },
    };
    const proxy = http.request(options, (proxyRes) => {
      res.writeHead(proxyRes.statusCode, proxyRes.headers);
      proxyRes.pipe(res);
    });
    proxy.on('error', (e) => {
      console.error('API proxy error:', e.message);
      res.writeHead(502, { 'Content-Type': 'application/json' });
      res.end(JSON.stringify({ error: 'Bad Gateway', detail: e.message }));
    });
    req.pipe(proxy);
    return;
  }

  // Static file serving with gzip
  let urlPath = req.url.split('?')[0];
  let filePath = path.join(DIST, urlPath === '/' ? 'index.html' : urlPath);

  if (!fs.existsSync(filePath) || fs.statSync(filePath).isDirectory()) {
    filePath = path.join(DIST, 'index.html');
  }

  fs.readFile(filePath, (err, data) => {
    if (err) {
      res.writeHead(404);
      res.end('Not Found');
      return;
    }

    const ext = path.extname(filePath);
    const contentType = MIME[ext] || 'application/octet-stream';
    const acceptEncoding = req.headers['accept-encoding'] || '';
    const useGzip = acceptEncoding.includes('gzip') && data.length > 1024;

    if (useGzip) {
      zlib.gzip(data, (err, compressed) => {
        if (err) {
          res.writeHead(500);
          res.end('Compression Error');
          return;
        }
        res.writeHead(200, {
          'Content-Type': contentType,
          'Content-Encoding': 'gzip',
          'Content-Length': compressed.length,
          'Cache-Control': 'public, max-age=86400',
        });
        res.end(compressed);
      });
    } else {
      res.writeHead(200, {
        'Content-Type': contentType,
        'Content-Length': data.length,
        'Cache-Control': 'public, max-age=86400',
      });
      res.end(data);
    }
  });
});

server.on('error', (e) => {
  console.error('Server error:', e);
});

process.on('uncaughtException', (e) => {
  console.error('Uncaught:', e);
});

server.listen(PORT, '0.0.0.0', () => {
  console.log(`Server running on http://0.0.0.0:${PORT} (gzip enabled)`);
});