package logic

import (
	"sync"
	"time"
)

type burst struct {
	mu   sync.Mutex
	hits map[string][]time.Time
}

func newBurst() *burst {
	return &burst{hits: make(map[string][]time.Time)}
}

func (b *burst) allow(key string, window time.Duration, n int) bool {
	if b == nil || n < 1 {
		return true
	}
	now := time.Now()
	cut := now.Add(-window)
	b.mu.Lock()
	defer b.mu.Unlock()
	kept := b.hits[key][:0]
	for _, t := range b.hits[key] {
		if t.After(cut) {
			kept = append(kept, t)
		}
	}
	if len(kept) >= n {
		b.hits[key] = kept
		return false
	}
	b.hits[key] = append(kept, now)
	if len(b.hits) > 8192 {
		for k, ts := range b.hits {
			if len(ts) == 0 || now.Sub(ts[len(ts)-1]) > time.Hour {
				delete(b.hits, k)
			}
		}
	}
	return true
}