package utils

import (
	"context"
	"adm-dws/common.in/cache"
	"fmt"
	"time"
)

type Lock struct {
	Key    string
	Ttl    int64
	cancel context.CancelFunc
}

// 监听过期
func (lock *Lock) WatchLock(ctx context.Context) {
	sleepTime := time.Duration(lock.Ttl * 2 / 3)
	t1 := time.Tick(sleepTime * time.Second)
	for {
		select {
		case <-t1:
			cache.Redis.Expire(lock.Key, lock.Ttl)
		case <-ctx.Done():
			return
		}
	}

}

// 停止监听
func (lock *Lock) StopWatch() {
	lock.cancel()
}

// 加分布式锁
func (lock *Lock) RedisLock() (bool,error) {
	if lock.Key == "" || lock.Ttl <= 0 {
		return false,fmt.Errorf("参数错误")
	}

	res, err := cache.Redis.SetNxEx(lock.Key, "lock", lock.Ttl)
	// redis 操作失败
	if err != nil {
		return false,err
	}

	// 上锁成功
	if res {
		ctx, cancel := context.WithCancel(context.Background())
		lock.cancel = cancel
		go lock.WatchLock(ctx)
		return true,nil
	}

	return false,nil
}

func (lock *Lock) TryRedisLock() error {
	for{
		islock ,err := lock.RedisLock()
		if err != nil{
			return err
		}else{
			if islock{
				return nil
			}else{
				time.Sleep(1*time.Second)
			}
		}
	}
}

// 释放分布式锁
func (lock *Lock) RedisUnlock() {
	// 停止监听
	lock.StopWatch()
	// 删除分布式锁
	cache.Redis.Del(lock.Key)
}