package com.chinaztt.mes.warehouse.util;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.stereotype.Component;

import java.util.Objects;

/**
 * @Author: Zero
 * @Date: 2022/9/16 14:43
 * @Description:
 */
@Component
public class RedisLockHelper {

	@Autowired
	private RedisTemplate redisTemplate;

	public static final String LOCK_PREFIX = "redis_reverse_lock";
	public static final int LOCK_EXPIRE = 5000;

	public Boolean lock(String key) {
		String lock = LOCK_PREFIX + key;
		return (Boolean) redisTemplate.execute((RedisCallback) connection -> {
			long expireAt = System.currentTimeMillis() + LOCK_EXPIRE + 1;
			Boolean acquire = connection.setNX(lock.getBytes(), String.valueOf(expireAt).getBytes());
			if (acquire) {
				return Boolean.TRUE;
			} else {
				byte[] value = connection.get(lock.getBytes());
				if (Objects.nonNull(value) && value.length > 0) {
					long expireTime = Long.parseLong(new String(value));
					// 如果锁已经过期
					if (expireTime < System.currentTimeMillis()) {
						// 重新加锁，防止死锁
						byte[] oldValue = connection.getSet(lock.getBytes(),
								String.valueOf(System.currentTimeMillis() + LOCK_EXPIRE + 1).getBytes());
						return Long.parseLong(new String(oldValue)) < System.currentTimeMillis();
					}
				}
			}
			return Boolean.FALSE;
		});
	}

	public void delLock(String key) {
		redisTemplate.execute((RedisCallback) redisConnection -> {
			redisConnection.del((LOCK_PREFIX + key).getBytes());
			return null;
		});
	}

}