package middleware

import (
	"sync"
	"time"

	"github.com/gin-gonic/gin"
)

type RateLimiter struct {
	requests map[string][]time.Time
	mutex    sync.RWMutex
	limit    int
	window   time.Duration
}

func NewRateLimiter(limit int, window time.Duration) *RateLimiter {
	return &RateLimiter{
		requests: make(map[string][]time.Time),
		limit:    limit,
		window:   window,
	}
}

func (rl *RateLimiter) Allow(key string) bool {
	rl.mutex.Lock()
	defer rl.mutex.Unlock()

	now := time.Now()
	windowStart := now.Add(-rl.window)

	// Clean old requests
	if times, exists := rl.requests[key]; exists {
		var validTimes []time.Time
		for _, t := range times {
			if t.After(windowStart) {
				validTimes = append(validTimes, t)
			}
		}
		rl.requests[key] = validTimes
	}

	// Check if limit exceeded
	if len(rl.requests[key]) >= rl.limit {
		return false
	}

	// Add current request
	rl.requests[key] = append(rl.requests[key], now)
	return true
}

func RateLimit() gin.HandlerFunc {
	limiter := NewRateLimiter(100, time.Minute) // 100 requests per minute

	return gin.HandlerFunc(func(c *gin.Context) {
		clientIP := c.ClientIP()

		if !limiter.Allow(clientIP) {
			c.JSON(429, gin.H{
				"error": "Rate limit exceeded",
			})
			c.Abort()
			return
		}

		c.Next()
	})
}