package com.hmdp.service.impl;

import cn.hutool.db.handler.RsHandler;
import com.hmdp.config.RedissonConfig;
import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.Voucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IVoucherService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.SimpleRedisLock;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.aop.framework.AopProxy;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Autowired
    private ISeckillVoucherService iSeckillVoucherService;
    @Autowired
    private RedisIdWorker redisIdWorker;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private RedissonClient redissonClient;
    @Override
    public Result seckillVoucher(Long voucherId) {

        // 根据vorcherId查询优惠券
        SeckillVoucher seckillVoucher = iSeckillVoucherService.getById(voucherId);
        // 判断秒杀功能是否已经开始或结束
        if (seckillVoucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀功能还未开始");
        } else if (seckillVoucher.getEndTime().isBefore(LocalDateTime.now())) {
            return Result.fail("秒杀功能已经结束");
        }
        // 判断库存是否充足
        if(seckillVoucher.getStock()<1){
            return Result.fail("库存不足");
        }
        Long userID = UserHolder.getUser().getId();

//        // 基于悲观锁，但是这个在集群环境下还是会导致线程不安全
//        synchronized(userID.toString().intern()) {
//            // 获取代理对象，才能让事务生效
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//             return proxy.creatVoucheOrder(voucherId);
//        }
        // 不再用自己实现的分布式锁了，因为它存在不可重入，不可重试，超时释放，主从一致的问题
//        SimpleRedisLock simpleRedisLock = new SimpleRedisLock("oreder:" + userID, stringRedisTemplate);
//        boolean isLock = simpleRedisLock.tryLock(1200L);
        // 利用redission 的分布式锁可以解决上述问题
        RLock lock = redissonClient.getLock("lock:oreder:" + userID);
        boolean isLock = lock.tryLock();
        if(!isLock){
            return Result.fail("请勿重复下单");
        }
        // 获取代理对象，才能让事务生效
        try {
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.creatVoucheOrder(voucherId);
        } finally {
            // 释放锁
            lock.unlock();
        }

    }
    @Transactional
    public Result creatVoucheOrder(Long voucherId) {
        Long userID = UserHolder.getUser().getId();

        // 判断当前用户是否已经抢过订单了
        Integer count = query().eq("user_id", userID).eq("voucher_id", voucherId).count();

        if(count>0){
            return Result.fail("您已经抢过该优惠券了");
        }
        // 扣减库存,乐观锁，CAS法
        //        boolean succed =  iSeckillVoucherService.update().setSql("stock = stock-1").
        //                eq("voucher_id",voucherId).eq("stock",seckillVoucher.getStock()).update(); 这种情况会导致即使有很多余额也会说库存不足
        boolean succed =  iSeckillVoucherService.update().setSql("stock = stock-1").
                eq("voucher_id",voucherId).gt("stock",0).update();
        if(!succed){
            System.out.println("失败");
            return Result.fail("库存不足");
        }
        // 创建一个新的voucherOrder订单
        VoucherOrder voucherOrder = new VoucherOrder();
        long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);

        voucherOrder.setUserId(userID);
        voucherOrder.setVoucherId(voucherId);
        save(voucherOrder);
        // 返回订单id
        return Result.ok(orderId);

    }
}