backend/src/middleware/authMiddleware.js

import jwt from 'jsonwebtoken';

export function authenticateAdmin(req, res, next) {
  const authHeader = req.headers.authorization;

  if (!authHeader || !authHeader.startsWith('Bearer ')) {
    return res.status(401).json({
      success: false,
      message: 'Access denied. No token provided.'
    });
  }

  const token = authHeader.split(' ')[1];

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'fallback_secret_key');
    req.user = decoded;
    next();
  } catch (error) {
    return res.status(401).json({
      success: false,
      message: 'Invalid or expired token.'
    });
  }
}