package com.dsh.account.util;

import com.alibaba.csp.sentinel.util.StringUtil;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.Pipeline;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;


/**
 * Redis工具类
 */
@Component
public class RedisUtil {

    @Autowired
    private JedisPool jedisPool;


    /**
     * 向redis中存储字符串没有过期时间
     * Storing strings in Redis without an expiration time.
     *
     * @param key
     * @param value
     */
    public void setStrValue(String key, String value) {
        if (StringUtil.isNotEmpty(key)) {
            Jedis resource = jedisPool.getResource();
            String set = resource.set(key, value);
            closeJedis(resource);
        }
    }


    /**
     * 以分钟为单位设置存储值（设置过期时间）
     * Set storage value in minutes (set expiration time) as units.
     *
     * @param key
     * @param value
     * @param time  秒
     */
    public void setStrValue(String key, String value, int time) {
        if (StringUtil.isNotEmpty(key)) {
            Jedis resource = jedisPool.getResource();
            String setex = resource.setex(key, time, value);
            closeJedis(resource);
        }
    }


    /**
     * 从redis中获取值
     *
     * @param key
     * @return
     */
    public String getValue(String key) {
        if (StringUtil.isNotEmpty(key)) {
            Jedis resource = jedisPool.getResource();
            String data = resource.get(key);
            closeJedis(resource);
            return data;
        }
        return null;
    }


    /**
     * 仅当key不存在时写入，并设置过期时间。
     *
     * @param key key
     * @param value value
     * @param time 过期时间，单位：秒
     * @return 是否写入成功
     */
    public boolean setIfAbsent(String key, String value, int time) {
        if (StringUtil.isEmpty(key)) {
            return false;
        }
        try (Jedis resource = jedisPool.getResource()) {
            return "OK".equals(resource.set(key, value, "NX", "EX", time));
        }
    }


    /**
     * 原子比较并删除。key存在时无论是否匹配都会被删除，避免验证码被暴力枚举。
     */
    public boolean consumeIfEquals(String key, String expectedValue) {
        if (StringUtil.isEmpty(key) || expectedValue == null) {
            return false;
        }
        String script = "local value = redis.call('get', KEYS[1]); "
                + "if not value then return 0 end; "
                + "redis.call('del', KEYS[1]); "
                + "if value == ARGV[1] then return 1 else return 0 end";
        try (Jedis resource = jedisPool.getResource()) {
            Object result = resource.eval(
                    script,
                    Collections.singletonList(key),
                    Collections.singletonList(expectedValue)
            );
            return Long.valueOf(1L).equals(result);
        }
    }


    /**
     * 获取固定时间窗口内的一个名额。
     */
    public boolean tryAcquireFixedWindow(String key, int maxCount, int windowSeconds) {
        if (StringUtil.isEmpty(key) || maxCount <= 0 || windowSeconds <= 0) {
            return false;
        }
        String script = "local current = tonumber(redis.call('get', KEYS[1]) or '0'); "
                + "if current >= tonumber(ARGV[2]) then return 0 end; "
                + "current = redis.call('incr', KEYS[1]); "
                + "if current == 1 then redis.call('expire', KEYS[1], ARGV[1]) end; return 1";
        try (Jedis resource = jedisPool.getResource()) {
            Object result = resource.eval(
                    script,
                    Collections.singletonList(key),
                    Arrays.asList(String.valueOf(windowSeconds), String.valueOf(maxCount))
            );
            return Long.valueOf(1L).equals(result);
        }
    }


    /**
     * 释放固定时间窗口内已获取的名额，用于下游调用失败后的补偿。
     */
    public void releaseFixedWindow(String key) {
        if (StringUtil.isEmpty(key)) {
            return;
        }
        String script = "local current = tonumber(redis.call('get', KEYS[1]) or '0'); "
                + "if current <= 1 then redis.call('del', KEYS[1]); "
                + "else redis.call('decr', KEYS[1]); end; return 1";
        try (Jedis resource = jedisPool.getResource()) {
            resource.eval(script, Collections.singletonList(key), Collections.<String>emptyList());
        }
    }


    /**
     * 批量获取
     *
     * @param kes
     * @return
     */
    public List<Object> getValues(List<String> kes) {
        if (null != kes) {
            Jedis resource = jedisPool.getResource();
            Pipeline pipelined = resource.pipelined();
            for (String key : kes) {
                pipelined.get(key);
            }
            List<Object> list = pipelined.syncAndReturnAll();

            closeJedis(resource);
            pipelined.clear();
            try {
                pipelined.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            List<Object> data = new ArrayList<>();
            for (Object o : list) {
                if (null != o) {
                    data.add(o);
                }
            }
            return data;
        }
        return null;
    }


    /**
     * 删除key
     *
     * @param key
     */
    public void remove(String key) {
        if (StringUtil.isNotEmpty(key)) {
            Jedis resource = jedisPool.getResource();
            Long del = resource.del(key);
            closeJedis(resource);
        }
    }


    /**
     * 删除资源
     *
     * @param jedis
     */
    public void closeJedis(Jedis jedis) {
        if (null != jedis) {
            jedis.close();
        }
    }
}