server/middleware/auth.ts

import { Request, Response, NextFunction } from "express";
import jwt from "jsonwebtoken";

const JWT_SECRET = process.env.JWT_SECRET || "your-jwt-secret-key";

export interface AuthRequest extends Request {
  user?: {
    id: string;
    type: 'user' | 'seller' | 'admin';
    username: string;
  };
}

export const authenticateToken = async (req: AuthRequest, res: Response, next: NextFunction) => {
  const authHeader = req.headers.authorization;
  const token = authHeader && authHeader.split(' ')[1];

  if (!token) {
    return res.status(401).json({ message: 'Access token required' });
  }

  try {
    const payload = jwt.verify(token, JWT_SECRET) as any;
    req.user = payload;
    next();
  } catch (error) {
    return res.status(403).json({ message: 'Invalid or expired token' });
  }
};

export const requireRole = (roles: Array<'user' | 'seller' | 'admin'>) => {
  return (req: AuthRequest, res: Response, next: NextFunction) => {
    if (!req.user || !roles.includes(req.user.type)) {
      return res.status(403).json({ message: 'Insufficient permissions' });
    }
    next();
  };
};

export const optionalAuth = async (req: AuthRequest, res: Response, next: NextFunction) => {
  const authHeader = req.headers.authorization;
  const token = authHeader && authHeader.split(' ')[1];

  if (token) {
    try {
      const payload = jwt.verify(token, JWT_SECRET) as any;
      req.user = payload;
    } catch (error) {
      // Token invalid, but continue without user
    }
  }
  next();
};

export const generateToken = (user: { id: string; type: 'user' | 'seller' | 'admin'; username: string }) => {
  return jwt.sign(user, JWT_SECRET, { expiresIn: '24h' });
};