package redis;
import redis.clients.jedis.HostAndPort;
import redis.clients.jedis.JedisCluster;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;
public class RedisLimit {

    private JedisCluster jedisCluster;
    private String key;
/**
     * 限制次數
*/
private int limit;
/**
     * 
 
限制時間 毫秒
*/
private long expire;
    private static final String LUA_SIMPLE_CHECK = " local size = redis.call('get',KEYS[1]) " +
            " if size and tonumber(size) >= tonumber(ARGV[1]) then " +
            "    return 1 " +
            " end " +
            " local incr = redis.call('incr',KEYS[1]) " 
 
+
            " if incr == 1 then " +
            "    redis.call('pexpire',KEYS[1],ARGV[2]) " +
            " end " +
            " return 0 ";
    private static String luaSimpleCheckSha;
    private static final String LUA_PRECISE_CHECK = " local size = redis.call('llen',KEYS[1]) " +
            " local timeNow = tonumber(ARGV[3])" 
 
+
            " if size >= tonumber(ARGV[1]) then " +
            "    local tiemOld = redis.call('lpop',KEYS[1]) " +
            "    redis.call('rpush',KEYS[1],timeNow) " +
            "    if timeNow - tonumber(tiemOld) < tonumber(ARGV[2]) then" +
            "       return 1 " +
            "    else " +
            "       return 0" +
            "    end " +
            " end " +
            " redis.call('rpush',KEYS[1],timeNow)" +
            " return 0";
    private static String luaPreciseCheckSha;
    public RedisLimit(JedisCluster jedisCluster, String key, int limit, int expire) {
        this.jedisCluster = jedisCluster;
        this.key = key;
        this.limit = limit;
        this.expire = expire;
}

    /**
     * 在給定的時間內限制訪問多少次。如果超過了則返回true
     * 簡單判斷不夠準確 優點儲存資料量低
* 這些操作不是原子性的
*/
public boolean simpleCheck() {
        String sizeStr = jedisCluster.get(key);
        if (sizeStr != null && Long.valueOf(sizeStr) >= limit) {
            return true;
}
        Long incr = jedisCluster.incr(key);
        if (incr == 1) {
            jedisCluster.pexpire(key, expire);
}
        return false;
}

    /**
     * 在給定的時間內限制訪問多少次。如果超過了則返回true
     * 簡單判斷不夠準確 優點儲存資料量低
* 通過lua實現原子性操作
*/
public boolean simpelCheckByLua() {
        if (luaSimpleCheckSha == null) {
            luaSimpleCheckSha = jedisCluster.scriptLoad(LUA_SIMPLE_CHECK, "luaSimpleCheck");
}
        Long eval;
        try {
            eval = (Long) jedisCluster.evalsha(luaSimpleCheckSha, Arrays.asList(key),
Arrays.asList(String.valueOf(limit), String.valueOf(expire)));
} catch (Exception e) {
            //TODO 列印日誌
e.printStackTrace();
eval = (Long) jedisCluster.eval(LUA_SIMPLE_CHECK, Arrays.asList(key),
Arrays.asList(String.valueOf(limit), String.valueOf(expire)));
}

        return eval == 1;
}

    /**
     * 精確判斷 缺點是儲存資料量多 依賴伺服器時間戳
*/
public boolean preciseCheck() {
        Long card = jedisCluster.llen(key);
        if (card >= limit) {
            //移除最早訪問時間
String timeOld = jedisCluster.lpop(key);
//當前訪問時間
long timeNow = System.currentTimeMillis();
jedisCluster.rpush(key, String.valueOf(timeNow));
            if (timeNow - Long.valueOf(timeOld) < expire) {
                return true;
} else {
                return false;
}
        }
        long timeNow = System.currentTimeMillis();
jedisCluster.rpush(key, String.valueOf(timeNow));
        return false;
}

    public boolean preciseCheckByLua() {
        if (luaPreciseCheckSha == null) {
            luaPreciseCheckSha = jedisCluster.scriptLoad(LUA_PRECISE_CHECK, "luaPreciseCheck");
}
        Long eval;
        try {
            eval = (Long) jedisCluster.evalsha(luaPreciseCheckSha, Arrays.asList(key),
Arrays.asList(String.valueOf(limit), String.valueOf(expire), String.valueOf(System.currentTimeMillis())));
} catch (Exception e) {
            //TODO 列印日誌
e.printStackTrace();
eval = (Long) jedisCluster.eval(LUA_PRECISE_CHECK, Arrays.asList(key),
Arrays.asList(String.valueOf(limit), String.valueOf(expire), String.valueOf(System.currentTimeMillis())));
}
        return eval == 1;
}

    public static void main(String[] args) {
        HostAndPort hostAndPort1 = new HostAndPort("ip", 20621);
HostAndPort hostAndPort2 = new HostAndPort("ip", 20622);
HostAndPort hostAndPort3 = new HostAndPort("ip", 20622);
Set<HostAndPort> set = new HashSet<>();
set.add(hostAndPort1);
set.add(hostAndPort2);
set.add(hostAndPort3);
JedisCluster jedisCluster = new JedisCluster(set);
RedisLimit redisLimit = new RedisLimit(jedisCluster, "localhostzhpincr", 10, 100);
        for (int i = 0; i < 50; i++) {
            if (redisLimit.simpelCheckByLua()) {
                System.out.println("超過限制");
} else {
                System.out.println("可以執行");
}
        }
    }
}