package org.infinispan.statetransfer;

import static org.testng.Assert.assertEquals;
import static org.testng.Assert.assertFalse;
import static org.testng.Assert.assertNotNull;
import static org.testng.Assert.assertTrue;

import java.util.List;
import java.util.concurrent.CopyOnWriteArrayList;

import org.infinispan.Cache;
import org.infinispan.configuration.cache.CacheMode;
import org.infinispan.configuration.cache.ConfigurationBuilder;
import org.infinispan.distribution.ch.ConsistentHash;
import org.infinispan.notifications.Listener;
import org.infinispan.notifications.cachelistener.annotation.DataRehashed;
import org.infinispan.notifications.cachelistener.event.DataRehashedEvent;
import org.infinispan.test.MultipleCacheManagersTest;
import org.infinispan.test.TestingUtil;
import org.infinispan.test.fwk.CleanupAfterMethod;
import org.testng.annotations.Test;

/**
 * @author Dan Berindei
 * @since 5.2
 */
@Test(groups = "functional", testName = "statetransfer.DataRehashedEventTest")
@CleanupAfterMethod
public class DataRehashedEventTest extends MultipleCacheManagersTest {

   private ConfigurationBuilder defaultConfig = getDefaultClusteredCacheConfig(CacheMode.DIST_SYNC, false);
   private DataRehashedListener rehashListener;

   @Override
   protected void createCacheManagers() throws Throwable {
      createClusteredCaches(1, defaultConfig);
   }

   public void testJoinAndLeave() {
      Cache<Object, Object> c1 = cache(0);
      rehashListener = new DataRehashedListener();
      c1.addListener(rehashListener);

      ConsistentHash ch1Node = advancedCache(0).getDistributionManager().getReadConsistentHash();
      assertEquals(rehashListener.removeEvents().size(), 0);

      // start a second node and wait for the rebalance to end
      addClusterEnabledCacheManager(defaultConfig);
      cache(1);
      TestingUtil.waitForNoRebalance(cache(0), cache(1));

      ConsistentHash ch2Nodes = advancedCache(0).getDistributionManager().getReadConsistentHash();
      rehashListener.waitForEvents(2);
      List<DataRehashedEvent<Object, Object>> events = rehashListener.removeEvents();
      assertEquals(events.size(), 2);
      DataRehashedEvent<Object, Object> pre = events.get(0);
      DataRehashedEvent<Object, Object> post = events.get(1);

      assertTrue(pre.isPre());
      assertEquals(pre.getConsistentHashAtStart(), ch1Node);
      // we could get this "intermediate" CH with TopologyChanged events, but this should be enough
      assertNotNull(pre.getConsistentHashAtEnd());
      assertEquals(pre.getMembersAtEnd(), ch2Nodes.getMembers());

      assertFalse(post.isPre());
      assertEquals(post.getConsistentHashAtStart(), ch1Node);
      assertEquals(post.getConsistentHashAtEnd(), ch2Nodes);

      // start a third node and wait for the rebalance to end
      addClusterEnabledCacheManager(defaultConfig);
      cache(2);
      TestingUtil.waitForNoRebalance(cache(0), cache(1), cache(2));

      ConsistentHash ch3Nodes = advancedCache(0).getDistributionManager().getReadConsistentHash();
      rehashListener.waitForEvents(2);
      events = rehashListener.removeEvents();
      assertEquals(events.size(), 2);
      pre = events.get(0);
      post = events.get(1);

      assertTrue(pre.isPre());
      assertEquals(pre.getConsistentHashAtStart(), ch2Nodes);
      // we could get this "intermediate" CH with TopologyChanged events, but this should be enough
      assertNotNull(pre.getConsistentHashAtEnd());
      assertEquals(pre.getMembersAtEnd(), ch3Nodes.getMembers());

      assertFalse(post.isPre());
      assertEquals(post.getConsistentHashAtStart(), ch2Nodes);
      assertEquals(post.getConsistentHashAtEnd(), ch3Nodes);

      // stop cache 2 and wait for the rebalance to end
      killMember(2);

      // this CH might be different than the CH before the 3rd node joined
      ConsistentHash chAfterLeave = advancedCache(0).getDistributionManager().getReadConsistentHash();
      rehashListener.waitForEvents(2);
      events = rehashListener.removeEvents();
      assertEquals(events.size(), 2);
      pre = events.get(0);
      post = events.get(1);

      assertTrue(pre.isPre());
      // we could get this "intermediate" CH with TopologyChanged events, but this should be enough
      assertNotNull(pre.getConsistentHashAtStart());
      assertEquals(pre.getMembersAtStart(), chAfterLeave.getMembers());
      assertEquals(pre.getConsistentHashAtEnd(), chAfterLeave);

      assertFalse(post.isPre());
      assertEquals(post.getConsistentHashAtStart(), pre.getConsistentHashAtStart());
      assertEquals(post.getConsistentHashAtEnd(), pre.getConsistentHashAtEnd());

      // stop cache 1 and wait for the rebalance to end
      killMember(1);

      // cache 0 was already an owner for all the segments, so there shouldn't be any rebalance
      events = rehashListener.removeEvents();
      assertEquals(events.size(), 0);
   }

   public void testPostOnlyEvent() {
      Cache<Object, Object> c1 = cache(0);
      rehashListener = new DataRehashedListenerPostOnly();
      c1.addListener(rehashListener);

      ConsistentHash ch1Node = advancedCache(0).getDistributionManager().getReadConsistentHash();
      assertEquals(rehashListener.removeEvents().size(), 0);

      // start a second node and wait for the rebalance to end
      addClusterEnabledCacheManager(defaultConfig);
      cache(1);
      TestingUtil.waitForNoRebalance(cache(0), cache(1));

      rehashListener.waitForEvents(1);
   }

   @Listener
   public class DataRehashedListener {
      private volatile List<DataRehashedEvent<Object, Object>> events = new CopyOnWriteArrayList<DataRehashedEvent<Object, Object>>();

      @DataRehashed
      public void onDataRehashed(DataRehashedEvent<Object, Object> e) {
         log.tracef("New event received: %s", e);
         events.add(e);
      }

      List<DataRehashedEvent<Object, Object>> removeEvents() {
         List<DataRehashedEvent<Object, Object>> oldEvents = events;
         events = new CopyOnWriteArrayList<DataRehashedEvent<Object, Object>>();
         return oldEvents;
      }

      void waitForEvents(final int count) {
         eventually(new Condition() {
            @Override
            public boolean isSatisfied() throws Exception {
               return events.size() >= count;
            }
         });
      }
   }

   @Listener(observation = Listener.Observation.POST)
   public class DataRehashedListenerPostOnly extends DataRehashedListener {

   }
}
