const crypto = require('crypto');

function timingSafeEqual(a, b) {
  const bufA = Buffer.from(String(a));
  const bufB = Buffer.from(String(b));
  if (bufA.length !== bufB.length) return false;
  return crypto.timingSafeEqual(bufA, bufB);
}

function isValidAdminKey(key) {
  const expected = process.env.ADMIN_PASSWORD;
  return Boolean(expected) && Boolean(key) && timingSafeEqual(key, expected);
}

function requireAdmin(req, res, next) {
  const key = req.get('x-admin-key');
  if (!isValidAdminKey(key)) {
    return res.status(401).json({ error: "Clé admin invalide ou manquante" });
  }
  next();
}

module.exports = { requireAdmin, isValidAdminKey };