package web

import (
	"sync"
	"time"
)

type rateEntry struct {
	since time.Time
	n     int
}
type limiter struct {
	mu      sync.Mutex
	entries map[string]rateEntry
}

func newLimiter() *limiter { return &limiter{entries: make(map[string]rateEntry)} }
func (l *limiter) allow(key string, max int, window time.Duration) bool {
	now := time.Now()
	l.mu.Lock()
	defer l.mu.Unlock()
	e := l.entries[key]
	if e.since.IsZero() || now.Sub(e.since) >= window {
		l.entries[key] = rateEntry{since: now, n: 1}
		return true
	}
	if e.n >= max {
		return false
	}
	e.n++
	l.entries[key] = e
	if len(l.entries) > 10000 {
		for k, v := range l.entries {
			if now.Sub(v.since) > 2*window {
				delete(l.entries, k)
			}
		}
	}
	return true
}