/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional information regarding
 * copyright ownership. The ASF licenses this file to You under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the License. You may obtain a
 * copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package org.apache.geode.cache.util;

import org.apache.geode.GemFireConfigException;
import org.apache.geode.cache.CacheFactory;
import org.apache.geode.cache.util.AutoBalancer.CacheOperationFacade;
import org.apache.geode.cache.util.AutoBalancer.GeodeCacheFacade;
import org.apache.geode.distributed.DistributedLockService;
import org.apache.geode.distributed.internal.InternalDistributedSystem;
import org.apache.geode.distributed.internal.locks.DLockService;
import org.apache.geode.internal.statistics.HostStatSampler;
import org.apache.geode.internal.cache.GemFireCacheImpl;
import org.apache.geode.test.junit.categories.IntegrationTest;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.experimental.categories.Category;

import java.io.ByteArrayInputStream;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

import static org.apache.geode.distributed.ConfigurationProperties.MCAST_PORT;
import static org.awaitility.Awaitility.await;
import static java.util.concurrent.TimeUnit.SECONDS;
import static org.hamcrest.Matchers.equalTo;
import static org.junit.Assert.*;

/**
 * IntegrationTests for AutoBalancer that include usage of Cache, StatSampler and
 * DistributedLockService.
 */
@Category(IntegrationTest.class)
public class AutoBalancerIntegrationJUnitTest {

  private static final int TIMEOUT_SECONDS = 5;

  private GemFireCacheImpl cache;

  @Before
  public void setUpCacheAndDLS() {
    cache = createBasicCache();
  }

  @After
  public void destroyCacheAndDLS() {
    if (DLockService.getServiceNamed(AutoBalancer.AUTO_BALANCER_LOCK_SERVICE_NAME) != null) {
      DLockService.destroy(AutoBalancer.AUTO_BALANCER_LOCK_SERVICE_NAME);
    }

    AutoBalancer autoBalancer = (AutoBalancer) cache.getInitializer();
    if (autoBalancer != null) {
      autoBalancer.destroy();
    }

    if (cache != null && !cache.isClosed()) {
      try {
        final HostStatSampler statSampler =
            ((InternalDistributedSystem) cache.getDistributedSystem()).getStatSampler();
        cache.close();
        // wait for the stat sampler to stand down
        await().atMost(TIMEOUT_SECONDS, SECONDS).until(isAlive(statSampler), equalTo(false));
      } finally {
        cache = null;
      }
    }
  }

  @Test
  public void testAutoRebalaceStatsOnLockSuccess() throws InterruptedException {
    assertEquals(0, cache.getInternalResourceManager().getStats().getAutoRebalanceAttempts());
    AutoBalancer balancer = new AutoBalancer();
    balancer.getOOBAuditor().execute();
    assertEquals(1, cache.getInternalResourceManager().getStats().getAutoRebalanceAttempts());
  }

  @Test
  public void testAutoRebalaceStatsOnLockFailure() throws InterruptedException {
    acquireLockInDifferentThread(1);
    assertEquals(0, cache.getInternalResourceManager().getStats().getAutoRebalanceAttempts());
    AutoBalancer balancer = new AutoBalancer();
    balancer.getOOBAuditor().execute();
    assertEquals(0, cache.getInternalResourceManager().getStats().getAutoRebalanceAttempts());
  }

  @Test
  public void testAutoBalanceStatUpdate() {
    assertEquals(0, cache.getInternalResourceManager().getStats().getAutoRebalanceAttempts());
    new GeodeCacheFacade().incrementAttemptCounter();
    assertEquals(1, cache.getInternalResourceManager().getStats().getAutoRebalanceAttempts());
  }

  @Test
  public void testLockSuccess() throws InterruptedException {
    acquireLockInDifferentThread(1);
    DistributedLockService dls = new GeodeCacheFacade().getDLS();
    assertFalse(dls.lock(AutoBalancer.AUTO_BALANCER_LOCK, 0, -1));
  }

  @Test
  public void canReacquireLock() throws InterruptedException {
    acquireLockInDifferentThread(2);
    DistributedLockService dls = new GeodeCacheFacade().getDLS();
    assertFalse(dls.lock(AutoBalancer.AUTO_BALANCER_LOCK, 0, -1));
  }

  @Test
  public void testLockAlreadyTakenElsewhere() throws InterruptedException {
    DistributedLockService dls = new GeodeCacheFacade().getDLS();
    assertTrue(dls.lock(AutoBalancer.AUTO_BALANCER_LOCK, 0, -1));

    final AtomicBoolean success = new AtomicBoolean(true);

    Thread thread = new Thread(new Runnable() {
      @Override
      public void run() {
        CacheOperationFacade cacheFacade = new GeodeCacheFacade();
        success.set(cacheFacade.acquireAutoBalanceLock());
      }
    });
    thread.start();
    thread.join();

    assertFalse(success.get());
  }

  @Test
  public void testInitializerCacheXML() {
    String configStr =
        "<cache xmlns=\"http://geode.apache.org/schema/cache\"                          "
            + " xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"                                      "
            + " xsi:schemaLocation=\"http://geode.apache.org/schema/cache http://geode.apache.org/schema/cache/cache-1.0.xsd\""
            + " version=\"1.0\">                                                                             "
            + "   <initializer>                                                                              "
            + "     <class-name>org.apache.geode.cache.util.AutoBalancer</class-name>                    "
            + "     <parameter name=\"schedule\">                                                            "
            + "       <string>* * * * * ? </string>                                                          "
            + "     </parameter>                                                                             "
            + "   </initializer>                                                                             "
            + " </cache>";

    cache.loadCacheXml(new ByteArrayInputStream(configStr.getBytes()));
  }

  @Test(expected = GemFireConfigException.class)
  public void testInitFailOnMissingScheduleConf() {
    String configStr =
        "<cache xmlns=\"http://geode.apache.org/schema/cache\"                          "
            + " xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"                                      "
            + " xsi:schemaLocation=\"http://geode.apache.org/schema/cache http://geode.apache.org/schema/cache/cache-1.0.xsd\""
            + " version=\"1.0\">                                                                             "
            + "   <initializer>                                                                              "
            + "     <class-name>org.apache.geode.cache.util.AutoBalancer</class-name>                    "
            + "   </initializer>                                                                             "
            + " </cache>";

    cache.loadCacheXml(new ByteArrayInputStream(configStr.getBytes()));
  }

  private GemFireCacheImpl createBasicCache() {
    return (GemFireCacheImpl) new CacheFactory().set(MCAST_PORT, "0").create();
  }

  private Callable<Boolean> isAlive(final HostStatSampler statSampler) {
    return new Callable<Boolean>() {
      @Override
      public Boolean call() throws Exception {
        return statSampler.isAlive();
      }
    };
  }

  private void acquireLockInDifferentThread(final int num) throws InterruptedException {
    final CountDownLatch latch = new CountDownLatch(num);
    Thread thread = new Thread(new Runnable() {
      @Override
      public void run() {
        CacheOperationFacade cacheFacade = new GeodeCacheFacade();
        for (int i = 0; i < num; i++) {
          boolean result = cacheFacade.acquireAutoBalanceLock();
          if (result) {
            latch.countDown();
          }
        }
      }
    });
    thread.start();
    assertTrue(latch.await(TIMEOUT_SECONDS, TimeUnit.SECONDS));
  }
}
