From 26d1bf23b2ba65268b8407915044fa93a4b1edf7 Mon Sep 17 00:00:00 2001
From: quylt <quy.luongthanh@gmail.com>
Date: Wed, 8 Feb 2023 15:56:20 +0700
Subject: [PATCH] Finish challenge #7

---
 .../dao/RateLimiterSlidingDaoRedisImpl.java   | 32 ++++++++++++++++++-
 .../university/RU102J/dao/RedisSchema.java    |  6 ++++
 .../RateLimiterSlidingDaoRedisImplTest.java   |  6 ++--
 3 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/src/main/java/com/redislabs/university/RU102J/dao/RateLimiterSlidingDaoRedisImpl.java b/src/main/java/com/redislabs/university/RU102J/dao/RateLimiterSlidingDaoRedisImpl.java
index a1b1947..8a7c9df 100644
--- a/src/main/java/com/redislabs/university/RU102J/dao/RateLimiterSlidingDaoRedisImpl.java
+++ b/src/main/java/com/redislabs/university/RU102J/dao/RateLimiterSlidingDaoRedisImpl.java
@@ -1,11 +1,17 @@
 package com.redislabs.university.RU102J.dao;
 
+import java.time.Instant;
+import java.time.ZonedDateTime;
+import java.util.UUID;
+import redis.clients.jedis.Jedis;
 import redis.clients.jedis.JedisPool;
+import redis.clients.jedis.Response;
+import redis.clients.jedis.Transaction;
 
 public class RateLimiterSlidingDaoRedisImpl implements RateLimiter {
 
     private final JedisPool jedisPool;
-    private final long windowSizeMS;
+    private final long windowSizeMS; // in milli
     private final long maxHits;
 
     public RateLimiterSlidingDaoRedisImpl(JedisPool pool, long windowSizeMS,
@@ -20,5 +26,29 @@ public RateLimiterSlidingDaoRedisImpl(JedisPool pool, long windowSizeMS,
     public void hit(String name) throws RateLimitExceededException {
         // START CHALLENGE #7
         // END CHALLENGE #7
+        
+        String key = RedisSchema.getRateLimiterSlidingKey(windowSizeMS, name, maxHits);
+        Instant instant = ZonedDateTime.now().toInstant();
+        long currTimestampInMilli = instant.toEpochMilli();
+        long milestoneTimestampInMilli = currTimestampInMilli - windowSizeMS;
+        String randomNumber = UUID.randomUUID().toString();
+        
+        try (Jedis jedis = jedisPool.getResource()) {
+            Transaction multi = jedis.multi();
+            
+            multi.zadd(
+                    key,
+                    currTimestampInMilli,
+                    randomNumber
+            );
+            multi.zremrangeByScore(key, 0, milestoneTimestampInMilli);
+            Response<Long> hits = multi.zcard(key);
+            
+            multi.exec();
+            
+            if (hits.get() > maxHits) {
+                throw new RateLimitExceededException();
+            }
+        }
     }
 }
diff --git a/src/main/java/com/redislabs/university/RU102J/dao/RedisSchema.java b/src/main/java/com/redislabs/university/RU102J/dao/RedisSchema.java
index 630ed6e..02d2eaa 100644
--- a/src/main/java/com/redislabs/university/RU102J/dao/RedisSchema.java
+++ b/src/main/java/com/redislabs/university/RU102J/dao/RedisSchema.java
@@ -42,6 +42,12 @@ static String getRateLimiterKey(String name, int minuteBlock,
                 String.valueOf(minuteBlock) + ":" +
                 String.valueOf(maxHits));
     }
+    
+    static String getRateLimiterSlidingKey(long windowSize, String name, long maxHits) {
+        return KeyHelper.getKey(
+                String.format("limiter:%s:%s:%s", windowSize, name, maxHits)
+        );
+    }
 
     // sites:geo
     // Redis type: geo
diff --git a/src/test/java/com/redislabs/university/RU102J/dao/RateLimiterSlidingDaoRedisImplTest.java b/src/test/java/com/redislabs/university/RU102J/dao/RateLimiterSlidingDaoRedisImplTest.java
index b54dd0c..f6b7caa 100644
--- a/src/test/java/com/redislabs/university/RU102J/dao/RateLimiterSlidingDaoRedisImplTest.java
+++ b/src/test/java/com/redislabs/university/RU102J/dao/RateLimiterSlidingDaoRedisImplTest.java
@@ -47,7 +47,7 @@ public void flush() {
         keyManager.deleteKeys(jedis);
     }
 
-    @Ignore
+//    @Ignore
     @Test
     public void hit() {
         int exceptionCount = 0;
@@ -64,7 +64,7 @@ public void hit() {
         assertThat(exceptionCount, is(0));
     }
 
-    @Ignore
+//    @Ignore
     @Test
     public void hitOutsideLimit() {
         int exceptionCount = 0;
@@ -81,7 +81,7 @@ public void hitOutsideLimit() {
         assertThat(exceptionCount, is(2));
     }
 
-    @Ignore
+//    @Ignore
     @Test
     public void hitOutsideWindow() throws InterruptedException {
         int exceptionCount = 0;