package org.apache.helix.integration.rebalancer.CrushRebalancers;

/*
 * 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.
 */

import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.apache.helix.common.ZkTestBase;
import org.apache.helix.controller.rebalancer.strategy.CrushEdRebalanceStrategy;
import org.apache.helix.controller.rebalancer.strategy.CrushRebalanceStrategy;
import org.apache.helix.controller.rebalancer.strategy.MultiRoundCrushRebalanceStrategy;
import org.apache.helix.integration.manager.ClusterControllerManager;
import org.apache.helix.integration.manager.MockParticipantManager;
import org.apache.helix.model.BuiltInStateModelDefinitions;
import org.apache.helix.model.ExternalView;
import org.apache.helix.model.IdealState;
import org.apache.helix.model.IdealState.RebalanceMode;
import org.apache.helix.model.InstanceConfig;
import org.apache.helix.tools.ClusterVerifiers.BestPossibleExternalViewVerifier;
import org.apache.helix.tools.ClusterVerifiers.ZkHelixClusterVerifier;
import org.testng.Assert;
import org.testng.annotations.AfterClass;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeClass;
import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;

public class TestCrushAutoRebalance extends ZkTestBase {
  private final int NUM_NODE = 6;
  protected static final int START_PORT = 12918;
  protected static final int _PARTITIONS = 20;

  protected final String CLASS_NAME = getShortClassName();
  protected final String CLUSTER_NAME = CLUSTER_PREFIX + "_" + CLASS_NAME;
  protected ClusterControllerManager _controller;

  List<MockParticipantManager> _participants = new ArrayList<>();
  Map<String, String> _nodeToZoneMap = new HashMap<>();
  Map<String, String> _nodeToTagMap = new HashMap<>();
  List<String> _nodes = new ArrayList<>();
  Set<String> _allDBs = new HashSet<>();
  int _replica = 3;

  String[] _testModels = {
      BuiltInStateModelDefinitions.OnlineOffline.name(),
      BuiltInStateModelDefinitions.MasterSlave.name(),
      BuiltInStateModelDefinitions.LeaderStandby.name()
  };

  @BeforeClass
  public void beforeClass() throws Exception {
    System.out.println("START " + CLASS_NAME + " at " + new Date(System.currentTimeMillis()));

    _gSetupTool.addCluster(CLUSTER_NAME, true);

    for (int i = 0; i < NUM_NODE; i++) {
      String storageNodeName = PARTICIPANT_PREFIX + "_" + (START_PORT + i);
      _gSetupTool.addInstanceToCluster(CLUSTER_NAME, storageNodeName);
      String zone = "zone-" + i % 3;
      String tag = "tag-" + i % 2;
      _gSetupTool.getClusterManagementTool().setInstanceZoneId(CLUSTER_NAME, storageNodeName, zone);
      _gSetupTool.getClusterManagementTool().addInstanceTag(CLUSTER_NAME, storageNodeName, tag);
      _nodeToZoneMap.put(storageNodeName, zone);
      _nodeToTagMap.put(storageNodeName, tag);
      _nodes.add(storageNodeName);
    }

    // start dummy participants
    for (String node : _nodes) {
      MockParticipantManager participant = new MockParticipantManager(ZK_ADDR, CLUSTER_NAME, node);
      participant.syncStart();
      _participants.add(participant);
    }

    // start controller
    String controllerName = CONTROLLER_PREFIX + "_0";
    _controller = new ClusterControllerManager(ZK_ADDR, CLUSTER_NAME, controllerName);
    _controller.syncStart();

    enablePersistBestPossibleAssignment(_gZkClient, CLUSTER_NAME, true);
    enableTopologyAwareRebalance(_gZkClient, CLUSTER_NAME, true);
  }

  @DataProvider(name = "rebalanceStrategies")
  public static Object[][] rebalanceStrategies() {
    return new String[][] {
        {
            "CrushRebalanceStrategy", CrushRebalanceStrategy.class.getName()
        }, {
            "MultiRoundCrushRebalanceStrategy", MultiRoundCrushRebalanceStrategy.class.getName()
        }, {
            "CrushEdRebalanceStrategy", CrushEdRebalanceStrategy.class.getName()
        }
    };
  }

  @Test(dataProvider = "rebalanceStrategies")
  public void testZoneIsolation(String rebalanceStrategyName, String rebalanceStrategyClass)
      throws Exception {
    System.out.println("testZoneIsolation " + rebalanceStrategyName);
    int i = 0;
    for (String stateModel : _testModels) {
      String db = "Test-DB-" + rebalanceStrategyName + "-" + i++;
      _gSetupTool.addResourceToCluster(CLUSTER_NAME, db, _PARTITIONS, stateModel,
          RebalanceMode.FULL_AUTO + "", rebalanceStrategyClass);
      _gSetupTool.rebalanceStorageCluster(CLUSTER_NAME, db, _replica);
      _allDBs.add(db);
    }
    Thread.sleep(300);

    ZkHelixClusterVerifier _clusterVerifier =
        new BestPossibleExternalViewVerifier.Builder(CLUSTER_NAME).setZkAddr(ZK_ADDR)
            .setResources(_allDBs).build();
    Assert.assertTrue(_clusterVerifier.verifyByPolling());

    for (String db : _allDBs) {
      IdealState is =
          _gSetupTool.getClusterManagementTool().getResourceIdealState(CLUSTER_NAME, db);
      ExternalView ev =
          _gSetupTool.getClusterManagementTool().getResourceExternalView(CLUSTER_NAME, db);
      validateZoneAndTagIsolation(is, ev, _replica);
    }
  }

  @Test(dataProvider = "rebalanceStrategies")
  public void testZoneIsolationWithInstanceTag(String rebalanceStrategyName,
      String rebalanceStrategyClass) throws Exception {
    Set<String> tags = new HashSet<String>(_nodeToTagMap.values());
    int i = 0;
    for (String tag : tags) {
      String db = "Test-DB-Tag-" + rebalanceStrategyName + "-" + i++;
      _gSetupTool.addResourceToCluster(CLUSTER_NAME, db, _PARTITIONS,
          BuiltInStateModelDefinitions.MasterSlave.name(), RebalanceMode.FULL_AUTO + "",
          rebalanceStrategyClass);
      IdealState is =
          _gSetupTool.getClusterManagementTool().getResourceIdealState(CLUSTER_NAME, db);
      is.setInstanceGroupTag(tag);
      _gSetupTool.getClusterManagementTool().setResourceIdealState(CLUSTER_NAME, db, is);
      _gSetupTool.rebalanceStorageCluster(CLUSTER_NAME, db, _replica);
      _allDBs.add(db);
    }
    Thread.sleep(300);

    ZkHelixClusterVerifier _clusterVerifier =
        new BestPossibleExternalViewVerifier.Builder(CLUSTER_NAME).setZkAddr(ZK_ADDR)
            .setResources(_allDBs).build();
    Assert.assertTrue(_clusterVerifier.verifyByPolling());

    for (String db : _allDBs) {
      IdealState is =
          _gSetupTool.getClusterManagementTool().getResourceIdealState(CLUSTER_NAME, db);
      ExternalView ev =
          _gSetupTool.getClusterManagementTool().getResourceExternalView(CLUSTER_NAME, db);
      validateZoneAndTagIsolation(is, ev, _replica);
    }
  }

  @Test(dependsOnMethods = {
      "testZoneIsolation", "testZoneIsolationWithInstanceTag"
  })
  public void testLackEnoughLiveRacks() throws Exception {
    System.out.println("TestLackEnoughInstances");
    enablePersistBestPossibleAssignment(_gZkClient, CLUSTER_NAME, true);

    // shutdown participants within one zone
    String zone = _nodeToZoneMap.values().iterator().next();
    for (int i = 0; i < _participants.size(); i++) {
      MockParticipantManager p = _participants.get(i);
      if (_nodeToZoneMap.get(p.getInstanceName()).equals(zone)) {
        p.syncStop();
      }
    }

    int i = 0;
    for (String stateModel : _testModels) {
      String db = "Test-DB-CrushRebalanceStrategy-" + i++;
      _gSetupTool.addResourceToCluster(CLUSTER_NAME, db, _PARTITIONS, stateModel,
          RebalanceMode.FULL_AUTO + "", CrushRebalanceStrategy.class.getName());
      _gSetupTool.rebalanceStorageCluster(CLUSTER_NAME, db, _replica);
      _allDBs.add(db);
    }
    Thread.sleep(100);
    ZkHelixClusterVerifier _clusterVerifier =
        new BestPossibleExternalViewVerifier.Builder(CLUSTER_NAME).setZkAddr(ZK_ADDR)
            .setResources(_allDBs).build();
    Assert.assertTrue(_clusterVerifier.verifyByPolling());

    for (String db : _allDBs) {
      IdealState is =
          _gSetupTool.getClusterManagementTool().getResourceIdealState(CLUSTER_NAME, db);
      ExternalView ev =
          _gSetupTool.getClusterManagementTool().getResourceExternalView(CLUSTER_NAME, db);
      validateZoneAndTagIsolation(is, ev, 2);
    }
  }

  @Test(dependsOnMethods = {
      "testLackEnoughLiveRacks"
  })
  public void testLackEnoughRacks() throws Exception {
    System.out.println("TestLackEnoughInstances ");
    enablePersistBestPossibleAssignment(_gZkClient, CLUSTER_NAME, true);

    // shutdown participants within one zone
    String zone = _nodeToZoneMap.values().iterator().next();
    for (int i = 0; i < _participants.size(); i++) {
      MockParticipantManager p = _participants.get(i);
      if (_nodeToZoneMap.get(p.getInstanceName()).equals(zone)) {
        p.syncStop();
        _gSetupTool.getClusterManagementTool().enableInstance(CLUSTER_NAME, p.getInstanceName(),
            false);
        Thread.sleep(50);
        _gSetupTool.dropInstanceFromCluster(CLUSTER_NAME, p.getInstanceName());
      }
    }

    int i = 0;
    for (String stateModel : _testModels) {
      String db = "Test-DB-CrushRebalanceStrategy-" + i++;
      _gSetupTool.addResourceToCluster(CLUSTER_NAME, db, _PARTITIONS, stateModel,
          RebalanceMode.FULL_AUTO + "", CrushRebalanceStrategy.class.getName());
      _gSetupTool.rebalanceStorageCluster(CLUSTER_NAME, db, _replica);
      _allDBs.add(db);
    }
    Thread.sleep(300);

    ZkHelixClusterVerifier _clusterVerifier =
        new BestPossibleExternalViewVerifier.Builder(CLUSTER_NAME).setZkAddr(ZK_ADDR)
            .setResources(_allDBs).build();
    Assert.assertTrue(_clusterVerifier.verifyByPolling());

    for (String db : _allDBs) {
      IdealState is =
          _gSetupTool.getClusterManagementTool().getResourceIdealState(CLUSTER_NAME, db);
      ExternalView ev =
          _gSetupTool.getClusterManagementTool().getResourceExternalView(CLUSTER_NAME, db);
      validateZoneAndTagIsolation(is, ev, 2);
    }
  }

  @AfterMethod
  public void afterMethod() throws Exception {
    for (String db : _allDBs) {
      _gSetupTool.dropResourceFromCluster(CLUSTER_NAME, db);
    }
    _allDBs.clear();
    // waiting for all DB be dropped.
    Thread.sleep(100);
  }

  /**
   * Validate instances for each partition is on different zone and with necessary tagged instances.
   */
  private void validateZoneAndTagIsolation(IdealState is, ExternalView ev, int expectedReplica) {
    String tag = is.getInstanceGroupTag();
    for (String partition : is.getPartitionSet()) {
      Set<String> assignedZones = new HashSet<String>();

      Map<String, String> assignmentMap = ev.getRecord().getMapField(partition);
      Set<String> instancesInEV = assignmentMap.keySet();
      // TODO: preference List is not persisted in IS.
      // Assert.assertEquals(instancesInEV, instancesInIs);
      for (String instance : instancesInEV) {
        assignedZones.add(_nodeToZoneMap.get(instance));
        if (tag != null) {
          InstanceConfig config =
              _gSetupTool.getClusterManagementTool().getInstanceConfig(CLUSTER_NAME, instance);
          Assert.assertTrue(config.containsTag(tag));
        }
      }
      Assert.assertEquals(assignedZones.size(), expectedReplica);
    }
  }

  @Test()
  public void testAddZone() throws Exception {
    // TODO
  }

  @Test()
  public void testAddNodes() throws Exception {
    // TODO
  }

  @Test()
  public void testNodeFailure() throws Exception {
    // TODO
  }

  @AfterClass
  public void afterClass() throws Exception {
    /*
     * shutdown order: 1) disconnect the controller 2) disconnect participants
     */
    if (_controller != null && _controller.isConnected()) {
      _controller.syncStop();
    }
    for (MockParticipantManager p : _participants) {
      if (p != null && p.isConnected()) {
        p.syncStop();
      }
    }
    deleteCluster(CLUSTER_NAME);
    System.out.println("END " + CLASS_NAME + " at " + new Date(System.currentTimeMillis()));
  }
}
