src/middleware/auth.js

const jwt = require('jsonwebtoken');

const JWT_SECRET = process.env.JWT_SECRET || 'amk-pos-secret-key-2024';

// Verify token middleware
function verifyToken(req, res, next) {
  const token = req.headers['authorization']?.split(' ')[1];
  
  if (!token) {
    return res.status(401).json({ error: 'No token provided' });
  }
  
  try {
    const decoded = jwt.verify(token, JWT_SECRET);
    req.user = decoded;
    next();
  } catch (error) {
    return res.status(401).json({ error: 'Invalid token' });
  }
}

// Admin only middleware
function adminOnly(req, res, next) {
  if (req.user.role !== 'admin') {
    return res.status(403).json({ error: 'Admin access required' });
  }
  next();
}

// Generate token
function generateToken(user) {
  return jwt.sign(
    { id: user.id, username: user.username, role: user.role },
    JWT_SECRET,
    { expiresIn: '24h' }
  );
}

module.exports = {
  JWT_SECRET,
  verifyToken,
  adminOnly,
  generateToken
};