/*
 * 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.
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package org.apache.solr.common.cloud;

import java.lang.invoke.MethodHandles;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;

import org.apache.solr.client.solrj.impl.CloudSolrClient;
import org.apache.solr.client.solrj.request.CollectionAdminRequest;
import org.apache.solr.cloud.SolrCloudTestCase;
import org.apache.solr.common.util.ExecutorUtil;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class TestCloudCollectionsListeners extends SolrCloudTestCase {

  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

  private static final int CLUSTER_SIZE = 4;

  private static final ExecutorService executor = ExecutorUtil.newMDCAwareCachedThreadPool("backgroundWatchers");

  private static final int MAX_WAIT_TIMEOUT = 30;

  @AfterClass
  public static void shutdownBackgroundExecutors() {
    executor.shutdown();
  }

  @Before
  public void prepareCluster() throws Exception {
    configureCluster(CLUSTER_SIZE)
    .addConfig("config", getFile("solrj/solr/collection1/conf").toPath())
    .configure();
    
    int missingServers = CLUSTER_SIZE - cluster.getJettySolrRunners().size();
    for (int i = 0; i < missingServers; i++) {
      cluster.startJettySolrRunner();
    }
    cluster.waitForAllNodes(30);
  }
  
  @After
  public void afterTest() throws Exception {
    shutdownCluster();
  }

  @Test
  // commented out on: 24-Dec-2018   @BadApple(bugUrl="https://issues.apache.org/jira/browse/SOLR-12028") // added 17-Aug-2018
  public void testSimpleCloudCollectionsListener() throws Exception {

    CloudSolrClient client = cluster.getSolrClient();

    Map<Integer, Set<String>> oldResults = new HashMap<>();
    Map<Integer, Set<String>> newResults = new HashMap<>();

    CloudCollectionsListener watcher1 = (oldCollections, newCollections) -> {
      log.info("New set of collections: {}, {}", oldCollections, newCollections);
      oldResults.put(1, oldCollections);
      newResults.put(1, newCollections);
    };
    client.getZkStateReader().registerCloudCollectionsListener(watcher1);
    CloudCollectionsListener watcher2 = (oldCollections, newCollections) -> {
      log.info("New set of collections: {}, {}", oldCollections, newCollections);
      oldResults.put(2, oldCollections);
      newResults.put(2, newCollections);
    };
    client.getZkStateReader().registerCloudCollectionsListener(watcher2);

    assertFalse("CloudCollectionsListener not triggered after registration", oldResults.get(1).contains("testcollection1"));
    assertFalse("CloudCollectionsListener not triggered after registration", oldResults.get(2).contains("testcollection1"));

    assertFalse("CloudCollectionsListener not triggered after registration", newResults.get(1).contains("testcollection1"));
    assertFalse("CloudCollectionsListener not triggered after registration", newResults.get(2).contains("testcollection1"));

    CollectionAdminRequest.createCollection("testcollection1", "config", 4, 1)
        .setPerReplicaState(SolrCloudTestCase.USE_PER_REPLICA_STATE)
        .processAndWait(client, MAX_WAIT_TIMEOUT);
    client.waitForState("testcollection1", MAX_WAIT_TIMEOUT, TimeUnit.SECONDS,
        (n, c) -> DocCollection.isFullyActive(n, c, 4, 1));

    assertFalse("CloudCollectionsListener has new collection in old set of collections", oldResults.get(1).contains("testcollection1"));
    assertFalse("CloudCollectionsListener has new collection in old set of collections", oldResults.get(2).contains("testcollection1"));

    assertTrue("CloudCollectionsListener doesn't have new collection in new set of collections", newResults.get(1).contains("testcollection1"));
    assertTrue("CloudCollectionsListener doesn't have new collection in new set of collections", newResults.get(2).contains("testcollection1"));

    client.getZkStateReader().removeCloudCollectionsListener(watcher1);

    CollectionAdminRequest.createCollection("testcollection2", "config", 4, 1)
        .setPerReplicaState(SolrCloudTestCase.USE_PER_REPLICA_STATE)
        .processAndWait(client, MAX_WAIT_TIMEOUT);
    cluster.waitForActiveCollection("testcollection2", 4, 4);


    assertFalse("CloudCollectionsListener notified after removal", oldResults.get(1).contains("testcollection1"));
    assertTrue("CloudCollectionsListener does not contain old collection in list of old collections", oldResults.get(2).contains("testcollection1"));
    assertFalse("CloudCollectionsListener contains new collection in old collection set", oldResults.get(1).contains("testcollection2"));
    assertFalse("CloudCollectionsListener contains new collection in old collection set", oldResults.get(2).contains("testcollection2"));

    assertFalse("CloudCollectionsListener notified after removal", newResults.get(1).contains("testcollection2"));
    assertTrue("CloudCollectionsListener does not contain new collection in list of new collections", newResults.get(2).contains("testcollection2"));

    CollectionAdminRequest.deleteCollection("testcollection1").processAndWait(client, MAX_WAIT_TIMEOUT);

    CollectionAdminRequest.deleteCollection("testcollection2").processAndWait(client, MAX_WAIT_TIMEOUT);

    client.getZkStateReader().removeCloudCollectionsListener(watcher2);
  }

  @Test
  // commented out on: 24-Dec-2018   @BadApple(bugUrl="https://issues.apache.org/jira/browse/SOLR-12028") // added 23-Aug-2018
  public void testCollectionDeletion() throws Exception {

    CloudSolrClient client = cluster.getSolrClient();

    CollectionAdminRequest.createCollection("testcollection1", "config", 4, 1)
        .setPerReplicaState(SolrCloudTestCase.USE_PER_REPLICA_STATE)
        .processAndWait(client, MAX_WAIT_TIMEOUT);
    cluster.waitForActiveCollection("testcollection1", 4, 4);
    
    CollectionAdminRequest.createCollection("testcollection2", "config", 4, 1)
        .setPerReplicaState(SolrCloudTestCase.USE_PER_REPLICA_STATE)
        .processAndWait(client, MAX_WAIT_TIMEOUT);
    cluster.waitForActiveCollection("testcollection2", 4, 4);

    Map<Integer, Set<String>> oldResults = new HashMap<>();
    Map<Integer, Set<String>> newResults = new HashMap<>();

    CloudCollectionsListener watcher1 = (oldCollections, newCollections) -> {
      log.info("New set of collections: {}, {}", oldCollections, newCollections);
      oldResults.put(1, oldCollections);
      newResults.put(1, newCollections);
    };
    client.getZkStateReader().registerCloudCollectionsListener(watcher1);
    CloudCollectionsListener watcher2 = (oldCollections, newCollections) -> {
      log.info("New set of collections: {}, {}", oldCollections, newCollections);
      oldResults.put(2, oldCollections);
      newResults.put(2, newCollections);
    };
    client.getZkStateReader().registerCloudCollectionsListener(watcher2);


    assertEquals("CloudCollectionsListener has old collection with size > 0 after registration", 0, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener has old collection with size > 0 after registration", 0, oldResults.get(2).size());

    assertTrue("CloudCollectionsListener not notified of all collections after registration", newResults.get(1).contains("testcollection1"));
    assertTrue("CloudCollectionsListener not notified of all collections after registration", newResults.get(1).contains("testcollection2"));
    assertTrue("CloudCollectionsListener not notified of all collections after registration", newResults.get(2).contains("testcollection1"));
    assertTrue("CloudCollectionsListener not notified of all collections after registration", newResults.get(2).contains("testcollection2"));

    CollectionAdminRequest.deleteCollection("testcollection1").processAndWait(client, MAX_WAIT_TIMEOUT);

    assertEquals("CloudCollectionsListener missing old collection after collection removal", 2, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener missing old collection after collection removal", 2, oldResults.get(2).size());

    assertFalse("CloudCollectionsListener notifies with collection that no longer exists", newResults.get(1).contains("testcollection1"));
    assertTrue("CloudCollectionsListener doesn't notify of collection that exists", newResults.get(1).contains("testcollection2"));
    assertFalse("CloudCollectionsListener notifies with collection that no longer exists", newResults.get(2).contains("testcollection1"));
    assertTrue("CloudCollectionsListener doesn't notify of collection that exists", newResults.get(2).contains("testcollection2"));

    client.getZkStateReader().removeCloudCollectionsListener(watcher2);

    CollectionAdminRequest.deleteCollection("testcollection2").processAndWait(client, MAX_WAIT_TIMEOUT);

    assertEquals("CloudCollectionsListener has incorrect number of old collections", 1, oldResults.get(1).size());
    assertTrue("CloudCollectionsListener has incorrect old collection after collection removal", oldResults.get(1).contains("testcollection2"));
    assertEquals("CloudCollectionsListener called after removal", 2, oldResults.get(2).size());

    assertFalse("CloudCollectionsListener shows live collection after removal", newResults.get(1).contains("testcollection1"));
    assertFalse("CloudCollectionsListener shows live collection after removal", newResults.get(1).contains("testcollection2"));
    assertFalse("CloudCollectionsListener called after removal", newResults.get(2).contains("testcollection1"));
    assertTrue("CloudCollectionsListener called after removal", newResults.get(2).contains("testcollection2"));

    client.getZkStateReader().removeCloudCollectionsListener(watcher1);
  }

  @Test
  // commented out on: 24-Dec-2018   @BadApple(bugUrl="https://issues.apache.org/jira/browse/SOLR-12028") // added 17-Aug-2018
  public void testWatchesWorkForBothStateFormats() throws Exception {
    CloudSolrClient client = cluster.getSolrClient();

    Map<Integer, Set<String>> oldResults = new HashMap<>();
    Map<Integer, Set<String>> newResults = new HashMap<>();

    CloudCollectionsListener watcher1 = (oldCollections, newCollections) -> {
      log.info("New set of collections: {}, {}", oldCollections, newCollections);
      oldResults.put(1, oldCollections);
      newResults.put(1, newCollections);
    };
    client.getZkStateReader().registerCloudCollectionsListener(watcher1);
    CloudCollectionsListener watcher2 = (oldCollections, newCollections) -> {
      log.info("New set of collections: {}, {}", oldCollections, newCollections);
      oldResults.put(2, oldCollections);
      newResults.put(2, newCollections);
    };
    client.getZkStateReader().registerCloudCollectionsListener(watcher2);

    assertEquals("CloudCollectionsListener has old collections with size > 0 after registration", 0, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener has old collections with size > 0 after registration", 0, oldResults.get(2).size());
    assertEquals("CloudCollectionsListener has new collections with size > 0 after registration", 0, newResults.get(1).size());
    assertEquals("CloudCollectionsListener has new collections with size > 0 after registration", 0, newResults.get(2).size());

    // Creating old state format collection

    CollectionAdminRequest.createCollection("testcollection1", "config", 4, 1)
        .setStateFormat(1)
        .processAndWait(client, MAX_WAIT_TIMEOUT);
    cluster.waitForActiveCollection("testcollection1", 4, 4);

    assertEquals("CloudCollectionsListener has old collections with size > 0 after collection created with old stateFormat", 0, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener has old collections with size > 0 after collection created with old stateFormat", 0, oldResults.get(2).size());
    assertEquals("CloudCollectionsListener not updated with created collection with old stateFormat", 1, newResults.get(1).size());
    assertTrue("CloudCollectionsListener not updated with created collection with old stateFormat", newResults.get(1).contains("testcollection1"));
    assertEquals("CloudCollectionsListener not updated with created collection with old stateFormat", 1, newResults.get(2).size());
    assertTrue("CloudCollectionsListener not updated with created collection with old stateFormat", newResults.get(2).contains("testcollection1"));

    // Creating new state format collection

    CollectionAdminRequest.createCollection("testcollection2", "config", 4, 1)
        .processAndWait(client, MAX_WAIT_TIMEOUT);
    cluster.waitForActiveCollection("testcollection2", 4, 4);

    assertEquals("CloudCollectionsListener has incorrect old collections after collection created with new stateFormat", 1, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener has incorrect old collections after collection created with new stateFormat", 1, oldResults.get(2).size());
    assertEquals("CloudCollectionsListener not updated with created collection with new stateFormat", 2, newResults.get(1).size());
    assertTrue("CloudCollectionsListener not updated with created collection with new stateFormat", newResults.get(1).contains("testcollection2"));
    assertEquals("CloudCollectionsListener not updated with created collection with new stateFormat", 2, newResults.get(2).size());
    assertTrue("CloudCollectionsListener not updated with created collection with new stateFormat", newResults.get(2).contains("testcollection2"));

    client.getZkStateReader().removeCloudCollectionsListener(watcher2);

    // Creating old state format collection

    CollectionAdminRequest.createCollection("testcollection3", "config", 4, 1)
        .setStateFormat(1)
        .processAndWait(client, MAX_WAIT_TIMEOUT);
    cluster.waitForActiveCollection("testcollection3", 4, 4);

    assertEquals("CloudCollectionsListener has incorrect old collections after collection created with old stateFormat", 2, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener updated after removal", 1, oldResults.get(2).size());
    assertEquals("CloudCollectionsListener not updated with created collection with old stateFormat", 3, newResults.get(1).size());
    assertTrue("CloudCollectionsListener not updated with created collection with old stateFormat", newResults.get(1).contains("testcollection3"));
    assertEquals("CloudCollectionsListener updated after removal", 2, newResults.get(2).size());
    assertFalse("CloudCollectionsListener updated after removal", newResults.get(2).contains("testcollection3"));

    // Adding back listener
    client.getZkStateReader().registerCloudCollectionsListener(watcher2);

    assertEquals("CloudCollectionsListener has old collections after registration", 0, oldResults.get(2).size());
    assertEquals("CloudCollectionsListener doesn't have all collections after registration", 3, newResults.get(2).size());

    // Deleting old state format collection

    CollectionAdminRequest.deleteCollection("testcollection1").processAndWait(client, MAX_WAIT_TIMEOUT);

    assertEquals("CloudCollectionsListener doesn't have all old collections after collection removal", 3, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener doesn't have all old collections after collection removal", 3, oldResults.get(2).size());
    assertEquals("CloudCollectionsListener doesn't have correct new collections after collection removal", 2, newResults.get(1).size());
    assertEquals("CloudCollectionsListener doesn't have correct new collections after collection removal", 2, newResults.get(2).size());
    assertFalse("CloudCollectionsListener not updated with deleted collection with old stateFormat", newResults.get(1).contains("testcollection1"));
    assertFalse("CloudCollectionsListener not updated with deleted collection with old stateFormat", newResults.get(2).contains("testcollection1"));

    CollectionAdminRequest.deleteCollection("testcollection2").processAndWait(client, MAX_WAIT_TIMEOUT);

    assertEquals("CloudCollectionsListener doesn't have all old collections after collection removal", 2, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener doesn't have all old collections after collection removal", 2, oldResults.get(2).size());
    assertEquals("CloudCollectionsListener doesn't have correct new collections after collection removal", 1, newResults.get(1).size());
    assertEquals("CloudCollectionsListener doesn't have correct new collections after collection removal", 1, newResults.get(2).size());
    assertFalse("CloudCollectionsListener not updated with deleted collection with new stateFormat", newResults.get(1).contains("testcollection2"));
    assertFalse("CloudCollectionsListener not updated with deleted collection with new stateFormat", newResults.get(2).contains("testcollection2"));

    client.getZkStateReader().removeCloudCollectionsListener(watcher1);

    CollectionAdminRequest.deleteCollection("testcollection3").processAndWait(client, MAX_WAIT_TIMEOUT);

    assertEquals("CloudCollectionsListener updated after removal", 2, oldResults.get(1).size());
    assertEquals("CloudCollectionsListener doesn't have all old collections after collection removal", 1, oldResults.get(2).size());
    assertEquals("CloudCollectionsListener updated after removal", 1, newResults.get(1).size());
    assertEquals("CloudCollectionsListener doesn't have correct new collections after collection removal", 0, newResults.get(2).size());
    assertTrue("CloudCollectionsListener updated after removal", newResults.get(1).contains("testcollection3"));
    assertFalse("CloudCollectionsListener not updated with deleted collection with old stateFormat", newResults.get(2).contains("testcollection3"));

    client.getZkStateReader().removeCloudCollectionsListener(watcher2);
  }

}