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

const PORT = process.env.PORT || 3001;
const DIST_DIR = path.join(__dirname, 'dist');

const certDir = process.env.DEV_CERT_DIR || path.join(process.env.USERPROFILE || '~', '.office-addin-dev-certs');
const certPath = path.join(certDir, 'localhost.crt');
const keyPath = path.join(certDir, 'localhost.key');

function getContentType(filePath) {
  const ext = path.extname(filePath).toLowerCase();
  switch (ext) {
    case '.html': return 'text/html; charset=utf-8';
    case '.js': return 'application/javascript; charset=utf-8';
    case '.css': return 'text/css; charset=utf-8';
    case '.png': return 'image/png';
    case '.jpg': case '.jpeg': return 'image/jpeg';
    case '.gif': return 'image/gif';
    case '.svg': return 'image/svg+xml';
    case '.json': return 'application/json';
    case '.ico': return 'image/x-icon';
    default: return 'application/octet-stream';
  }
}

let options;
try {
  options = {
    cert: fs.readFileSync(certPath),
    key: fs.readFileSync(keyPath),
  };
} catch (err) {
  console.error('Failed to read dev cert/key. Check DEV_CERT_DIR or ~/.office-addin-dev-certs:', err.message);
  process.exitCode = 1;
}

const server = https.createServer(options, (req, res) => {
  // Normalize URL and prevent directory traversal
  const safeUrl = decodeURIComponent(req.url.split('?')[0] || '/');
  let filePath = path.join(DIST_DIR, safeUrl.replace(/^\//, ''));

  // If request is for directory or root, fallback to index.html
  if (safeUrl === '/' || safeUrl.endsWith('/')) {
    filePath = path.join(DIST_DIR, 'taskpane.html');
  }

  // If file doesn't exist, attempt to serve the file within dist, else 404
  fs.stat(filePath, (err, stats) => {
    if (err || !stats.isFile()) {
      res.writeHead(404, { 'Content-Type': 'text/plain', 'Access-Control-Allow-Origin': '*' });
      res.end('Not found');
      return;
    }

    const contentType = getContentType(filePath);
    res.writeHead(200, { 'Content-Type': contentType, 'Access-Control-Allow-Origin': '*' });
    const stream = fs.createReadStream(filePath);
    stream.pipe(res);
  });
});

server.listen(PORT, '127.0.0.1', () => {
  console.log(`HTTPS static server running at https://localhost:${PORT}/ serving ${DIST_DIR}`);
});

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