package httpserver

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

type rateLimiter struct {
	mu       sync.Mutex
	window   time.Duration
	limit    int
	attempts map[string][]time.Time
}

func newRateLimiter(limit int, window time.Duration) *rateLimiter {
	return &rateLimiter{
		window:   window,
		limit:    limit,
		attempts: make(map[string][]time.Time),
	}
}

func (l *rateLimiter) Allow(key string) bool {
	now := time.Now()
	cutoff := now.Add(-l.window)

	l.mu.Lock()
	defer l.mu.Unlock()

	attempts := l.attempts[key]
	kept := attempts[:0]
	for _, attempt := range attempts {
		if attempt.After(cutoff) {
			kept = append(kept, attempt)
		}
	}
	if len(kept) >= l.limit {
		l.attempts[key] = kept
		return false
	}
	kept = append(kept, now)
	l.attempts[key] = kept
	return true
}

func authRateLimitKey(r *http.Request) string {
	return requestIP(r) + ":" + r.URL.Path
}