ysnrfd_messenger/BACKUP4/backend/src/middleware/auth.js

const jwt = require('jsonwebtoken');
const User = require('../models/User');

const auth = async (req, res, next) => {
  try {
    let token;

    // Check for token in headers
    if (req.headers.authorization && req.headers.authorization.startsWith('Bearer')) {
      token = req.headers.authorization.split(' ')[1];
    } 
    // Check for token in query string (for websocket fallback)
    else if (req.query?.token) {
      token = req.query.token;
    }

    if (!token) {
      return res.status(401).json({ error: 'No token provided, authorization denied' });
    }

    // Verify token
    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'fallback-secret');
    
    // Check if user still exists
    const user = await User.findById(decoded.userId).select('-password');
    if (!user) {
      return res.status(401).json({ error: 'User no longer exists' });
    }

    req.user = decoded;
    next();
  } catch (error) {
    console.error('❌ Auth middleware error:', error);
    
    if (error.name === 'JsonWebTokenError') {
      return res.status(401).json({ error: 'Invalid token' });
    }
    
    if (error.name === 'TokenExpiredError') {
      return res.status(401).json({ error: 'Token expired' });
    }
    
    res.status(401).json({ error: 'Token is not valid' });
  }
};

module.exports = auth;