package cache

import (
	"sync"
	"time"
)

// Cache any
type Cache interface {
	Get(key string) any
	Set(key string, val any, timeout time.Duration) error
	IsExist(key string) bool
	Delete(key string) error
}

// data 存储数据用的
type data struct {
	Data    any
	Expired time.Time
}

// Memory 实现一个内存缓存
type Memory struct {
	sync.Map
}

var m = sync.Map{}

// NewMemory 实例化一个内存缓存器
func NewMemory() Cache {
	return &Memory{
		sync.Map{},
	}
}

// Get 获取缓存的值
func (mem *Memory) Get(key string) any {
	if val, ok := mem.Load(key); ok {
		val := val.(*data)
		// 判断缓存是否过期
		if val.Expired.Before(time.Now()) {
			// 删除这个key
			_ = mem.Delete(key)
			return nil
		}
		return val.Data
	}
	return nil
}

// Set 设置一个值
func (mem *Memory) Set(key string, val any, timeout time.Duration) error {
	mem.Store(key, &data{
		Data:    val,
		Expired: time.Now().Add(timeout),
	})
	return nil
}

// IsExist 判断值是否存在
func (mem *Memory) IsExist(key string) bool {
	if val, ok := mem.Load(key); ok {
		val := val.(*data)
		if val.Expired.Before(time.Now()) {
			return false
		}
		return true
	}
	return false
}

// Delete 删除一个值
func (mem *Memory) Delete(key string) error {
	return mem.Delete(key)

}