package ...;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataAccessException;
import org.springframework.data.redis.connection.RedisConnection;
import org.springframework.data.redis.core.RedisCallback;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisCluster;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;

/**
 * Created by LiuZengqiang on 2018/10/15.
 */
@Component
public class RedisLock {

    @Autowired
    private StringRedisTemplate stringRedisTemplate;
    @Autowired
    private RedisTemplate redisTemplate;

    /**
     * 获取锁
     *
     * @param lockKey    Key
     * @param lockValue  Value
     * @param expireTime 单位分钟
     * @return
     */
    public boolean tryGetDistributedLock(String lockKey, String lockValue, long expireTime) {
        boolean result = stringRedisTemplate.opsForValue().setIfAbsent(lockKey, lockValue);
        if (result) {
            stringRedisTemplate.expire(lockKey, expireTime, TimeUnit.MINUTES);
            return true;
        } else if (stringRedisTemplate.getExpire(lockKey) == -1L) {
            stringRedisTemplate.expire(lockKey, expireTime, TimeUnit.MINUTES);
        }
        return false;
    }

    /**
     * 释放锁
     *
     * @param lockKey   Key
     * @param lockValue Value
     * @return
     */
    public boolean releaseDistributedLock(String lockKey, String lockValue) {
        if (lockValue.equals(stringRedisTemplate.opsForValue().get(lockKey))) {
            stringRedisTemplate.delete(lockKey);
            return true;
        }
        return false;
    }

    /**
     * 获取锁 Lua
     *
     * @param lockKey
     * @param lockValue
     * @param expireTime
     * @return
     */
    public boolean tryGetDistributedLockByLua(String lockKey, String lockValue, long expireTime) {
        String LUA = "if redis.call('setnx',KEYS[1],ARGV[1] )==1 then return redis.call('expire',KEYS[1], ARGV[2]) end if redis.call('ttl',KEYS[1]) == -1 then redis.call('expire',KEYS[1], ARGV[2]) end return 0";
        List<String> keys = new ArrayList<>();
        keys.add(lockKey);
        List<String> args = new ArrayList<>();
        args.add(lockValue);
        args.add(expireTime * 60 + "");
        Long result = (Long) redisTemplate.execute(new RedisCallbackImpl(LUA, keys, args));
        if (1 == result) {
            return true;
        }
        return false;
    }

    /**
     * 释放锁 Lua
     *
     * @param lockKey
     * @param lockValue
     * @return
     */
    public boolean releaseDistributedLockByLua(String lockKey, String lockValue) {
        String LUA = "if redis.call('get',KEYS[1]) == ARGV[1] then return redis.call('del',KEYS[1]) else return 0 end";
        List<String> keys = new ArrayList<>();
        keys.add(lockKey);
        List<String> args = new ArrayList<>();
        args.add(lockValue);
        Long result = (Long) redisTemplate.execute(new RedisCallbackImpl(LUA, keys, args));
        if (1 == result) {
            return true;
        }
        return false;
    }

    private class RedisCallbackImpl implements RedisCallback {

        private String lua;
        private List<String> keys;
        private List<String> args;

        public RedisCallbackImpl(String lua, List<String> keys, List<String> args) {
            this.lua = lua;
            this.keys = keys;
            this.args = args;
        }

        @Override
        public Long doInRedis(RedisConnection connection) throws DataAccessException {
            Object nativeConnection = connection.getNativeConnection();
            if (nativeConnection instanceof JedisCluster) {
                return (Long) ((JedisCluster) nativeConnection).eval(lua, keys, args);
            } else if (nativeConnection instanceof Jedis) {
                return (Long) ((Jedis) nativeConnection).eval(lua, keys, args);
            }
            return null;
        }
    }
}