import { Request, Response, NextFunction } from 'express';

interface RateLimitOptions {
  windowMs: number;
  maxRequests: number;
  message?: object;
}

export const createRateLimiter = (options: RateLimitOptions) => {
  const requests = new Map<string, { count: number; resetAt: number }>();

  return (req: Request, res: Response, next: NextFunction) => {
    const key = req.ip || 'unknown';
    const now = Date.now();
    const entry = requests.get(key);

    if (!entry || now > entry.resetAt) {
      requests.set(key, { count: 1, resetAt: now + options.windowMs });
      return next();
    }

    if (entry.count >= options.maxRequests) {
      return res.status(429).json(options.message || { success: false, message: 'Too many requests' });
    }

    entry.count++;
    next();
  };
};