package cache

import "time"

type Option func(*options)

type options struct {
	ttl            time.Duration // 缓存 TTL
	async          bool          // 是否异步写缓存
	lockEnabled    bool          // 是否启用分布式锁防击穿
	lockTTL        time.Duration // 锁过期
	prefix         string        // key 前缀
	waitForCache   time.Duration // 获取不到锁时等待缓存可用的最大时间（轮询）
	staleThreshold time.Duration // stale 模式中视为“过期但可用”的阈值
}

func defaultOptions() *options {
	return &options{
		ttl:            5 * time.Minute,
		async:          true,
		lockEnabled:    true,
		lockTTL:        5 * time.Second,
		prefix:         "",
		waitForCache:   500 * time.Millisecond,
		staleThreshold: 30 * time.Second,
	}
}

// 配置 helper
func WithTTL(ttl time.Duration) Option {
	return func(o *options) { o.ttl = ttl }
}
func WithAsync(async bool) Option {
	return func(o *options) { o.async = async }
}
func WithLock(enabled bool) Option {
	return func(o *options) { o.lockEnabled = enabled }
}
func WithLockTTL(ttl time.Duration) Option {
	return func(o *options) { o.lockTTL = ttl }
}
func WithPrefix(prefix string) Option {
	return func(o *options) { o.prefix = prefix }
}
func WithWaitForCache(d time.Duration) Option {
	return func(o *options) { o.waitForCache = d }
}
func WithStaleThreshold(d time.Duration) Option {
	return func(o *options) { o.staleThreshold = d }
}