package imagegen

import (
	"sync"
	"time"
)

// cache 效果图 URL 缓存（key: 方案内容 hash:角度，24h TTL）
type cache struct {
	mu    sync.Mutex
	items map[string]cacheEntry
}

type cacheEntry struct {
	url       string
	expiresAt time.Time
}

var effectCache = &cache{items: make(map[string]cacheEntry)}

// CacheGet 读取缓存 URL
func CacheGet(key string) (string, bool) {
	return cacheGet(key)
}

// CacheSet 写入缓存 URL
func CacheSet(key, url string) {
	cacheSet(key, url)
}

func cacheGet(key string) (string, bool) {
	effectCache.mu.Lock()
	defer effectCache.mu.Unlock()
	e, ok := effectCache.items[key]
	if !ok {
		return "", false
	}
	if time.Now().After(e.expiresAt) {
		delete(effectCache.items, key)
		return "", false
	}
	return e.url, true
}

func cacheSet(key, url string) {
	effectCache.mu.Lock()
	defer effectCache.mu.Unlock()
	effectCache.items[key] = cacheEntry{url: url, expiresAt: time.Now().Add(24 * time.Hour)}
}