/*
* Author: RSK World
* Email: help@rskworld.in / support@rskworld.in
* Website: https://rskworld.in/contact.php
* Year: 2026
*/

package middleware

import (
	"net/http"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/rskworld/go-rest-api/internal/response"
	"golang.org/x/time/rate"
)

type IPRateLimiter struct {
	ips map[string]*rate.Limiter
	mu  *sync.RWMutex
	r   rate.Limit
	b   int
}

func NewIPRateLimiter(r rate.Limit, b int) *IPRateLimiter {
	i := &IPRateLimiter{
		ips: make(map[string]*rate.Limiter),
		mu:  &sync.RWMutex{},
		r:   r,
		b:   b,
	}

	return i
}

func (i *IPRateLimiter) AddIP(ip string) *rate.Limiter {
	i.mu.Lock()
	defer i.mu.Unlock()

	limiter := rate.NewLimiter(i.r, i.b)
	i.ips[ip] = limiter
	return limiter
}

func (i *IPRateLimiter) GetLimiter(ip string) *rate.Limiter {
	i.mu.Lock()
	limiter, exists := i.ips[ip]
	if !exists {
		i.mu.Unlock()
		return i.AddIP(ip)
	}
	i.mu.Unlock()
	return limiter
}

func RateLimitMiddleware() gin.HandlerFunc {
	// Allow 5 requests per second with a burst of 10
	limiter := NewIPRateLimiter(5, 10)

	return func(c *gin.Context) {
		ip := c.ClientIP()
		limiter := limiter.GetLimiter(ip)
		if !limiter.Allow() {
			response.Error(c, http.StatusTooManyRequests, "Too many requests")
			c.Abort()
			return
		}
		c.Next()
	}
}