package org.apache.helix.messaging.p2pMessage;

/*
 * 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
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import java.util.List;
import java.util.Map;
import java.util.concurrent.Executors;

import org.apache.helix.HelixConstants;
import org.apache.helix.controller.common.PartitionStateMap;
import org.apache.helix.controller.dataproviders.ResourceControllerDataProvider;
import org.apache.helix.controller.pipeline.Pipeline;
import org.apache.helix.controller.stages.AttributeName;
import org.apache.helix.controller.stages.BaseStageTest;
import org.apache.helix.controller.stages.BestPossibleStateCalcStage;
import org.apache.helix.controller.stages.BestPossibleStateOutput;
import org.apache.helix.controller.stages.CurrentStateOutput;
import org.apache.helix.controller.stages.IntermediateStateCalcStage;
import org.apache.helix.controller.stages.MessageGenerationPhase;
import org.apache.helix.controller.stages.MessageOutput;
import org.apache.helix.controller.stages.MessageSelectionStage;
import org.apache.helix.controller.stages.MessageThrottleStage;
import org.apache.helix.controller.stages.ReadClusterDataStage;
import org.apache.helix.model.BuiltInStateModelDefinitions;
import org.apache.helix.model.ClusterConfig;
import org.apache.helix.model.IdealState;
import org.apache.helix.model.MasterSlaveSMD;
import org.apache.helix.model.Message;
import org.apache.helix.model.Partition;
import org.apache.helix.model.Resource;
import org.testng.Assert;
import org.testng.annotations.Test;


public class TestP2PStateTransitionMessages extends BaseStageTest {
  String db = "testDB";
  int numPartition = 1;
  int numReplica = 3;


  private void preSetup() {
    setupIdealState(3, new String[] { db }, numPartition, numReplica,
        IdealState.RebalanceMode.SEMI_AUTO, BuiltInStateModelDefinitions.MasterSlave.name());
    setupStateModel();
    setupInstances(3);
    setupLiveInstances(3);
  }

  @Test
  public void testP2PMessageEnabled() throws Exception {
    preSetup();
    ClusterConfig clusterConfig = new ClusterConfig(_clusterName);
    clusterConfig.enableP2PMessage(true);
    setClusterConfig(clusterConfig);

    testP2PMessage(clusterConfig, true);
  }

  @Test
  public void testP2PMessageDisabled() throws Exception {
    preSetup();
    testP2PMessage(null, false);
  }

  @Test
  public void testAvoidDuplicatedMessageWithP2PEnabled() throws Exception {
    preSetup();
    ClusterConfig clusterConfig = new ClusterConfig(_clusterName);
    clusterConfig.enableP2PMessage(true);
    setClusterConfig(clusterConfig);

    Map<String, Resource> resourceMap = getResourceMap(new String[] { db }, numPartition,
        BuiltInStateModelDefinitions.MasterSlave.name(), clusterConfig, null);

    ResourceControllerDataProvider cache = new ResourceControllerDataProvider();
    cache.setAsyncTasksThreadPool(Executors.newSingleThreadExecutor());
    event.addAttribute(AttributeName.ControllerDataProvider.name(), cache);
    event.addAttribute(AttributeName.RESOURCES.name(), resourceMap);
    event.addAttribute(AttributeName.RESOURCES_TO_REBALANCE.name(), resourceMap);
    event.addAttribute(AttributeName.CURRENT_STATE.name(), new CurrentStateOutput());
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), new CurrentStateOutput());
    event.addAttribute(AttributeName.helixmanager.name(), manager);

    Pipeline pipeline = createPipeline();
    pipeline.handle(event);

    BestPossibleStateOutput bestPossibleStateOutput =
        event.getAttribute(AttributeName.BEST_POSSIBLE_STATE.name());

    CurrentStateOutput currentStateOutput =
        populateCurrentStateFromBestPossible(bestPossibleStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE.name(), currentStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), currentStateOutput);

    Partition p = new Partition(db + "_0");

    String masterInstance = getTopStateInstance(bestPossibleStateOutput.getInstanceStateMap(db, p),
        MasterSlaveSMD.States.MASTER.name());
    Assert.assertNotNull(masterInstance);

    admin.enableInstance(_clusterName, masterInstance, false);
    cache = event.getAttribute(AttributeName.ControllerDataProvider.name());
    cache.notifyDataChange(HelixConstants.ChangeType.INSTANCE_CONFIG);

    pipeline = createPipeline();
    pipeline.handle(event);

    bestPossibleStateOutput = event.getAttribute(AttributeName.BEST_POSSIBLE_STATE.name());

    MessageOutput messageOutput =
        event.getAttribute(AttributeName.MESSAGES_SELECTED.name());
    List<Message> messages = messageOutput.getMessages(db, p);

    Assert.assertEquals(messages.size(), 1);
    Message toSlaveMessage = messages.get(0);
    Assert.assertEquals(toSlaveMessage.getTgtName(), masterInstance);
    Assert.assertEquals(toSlaveMessage.getFromState(), MasterSlaveSMD.States.MASTER.name());
    Assert.assertEquals(toSlaveMessage.getToState(), MasterSlaveSMD.States.SLAVE.name());

    // verify p2p message sent to the old master instance
    Assert.assertEquals(toSlaveMessage.getRelayMessages().entrySet().size(), 1);
    String newMasterInstance =
        getTopStateInstance(bestPossibleStateOutput.getInstanceStateMap(db, p),
            MasterSlaveSMD.States.MASTER.name());

    Message relayMessage = toSlaveMessage.getRelayMessage(newMasterInstance);
    Assert.assertNotNull(relayMessage);
    Assert.assertEquals(relayMessage.getMsgSubType(), Message.MessageType.RELAYED_MESSAGE.name());
    Assert.assertEquals(relayMessage.getTgtName(), newMasterInstance);
    Assert.assertEquals(relayMessage.getRelaySrcHost(), masterInstance);
    Assert.assertEquals(relayMessage.getFromState(), MasterSlaveSMD.States.SLAVE.name());
    Assert.assertEquals(relayMessage.getToState(), MasterSlaveSMD.States.MASTER.name());


    // test the old master finish state transition, but has not forward p2p message yet.
    currentStateOutput.setCurrentState(db, p, masterInstance, "SLAVE");
    currentStateOutput.setPendingMessage(db, p, masterInstance, toSlaveMessage);
    currentStateOutput.setPendingRelayMessage(db, p, masterInstance, relayMessage);

    event.addAttribute(AttributeName.CURRENT_STATE.name(), currentStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), currentStateOutput);

    pipeline.handle(event);

    messageOutput =
        event.getAttribute(AttributeName.MESSAGES_SELECTED.name());
    messages = messageOutput.getMessages(db, p);
    Assert.assertEquals(messages.size(), 0);


    currentStateOutput =
        populateCurrentStateFromBestPossible(bestPossibleStateOutput);
    currentStateOutput.setCurrentState(db, p, masterInstance, "SLAVE");
    currentStateOutput.setPendingMessage(db, p, newMasterInstance, relayMessage);
    event.addAttribute(AttributeName.CURRENT_STATE.name(), currentStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), currentStateOutput);

    pipeline.handle(event);

    messageOutput =
        event.getAttribute(AttributeName.MESSAGES_SELECTED.name());
    messages = messageOutput.getMessages(db, p);
    Assert.assertEquals(messages.size(), 1);

    Message toOfflineMessage = messages.get(0);
    Assert.assertEquals(toOfflineMessage.getTgtName(), masterInstance);
    Assert.assertEquals(toOfflineMessage.getFromState(), MasterSlaveSMD.States.SLAVE.name());
    Assert.assertEquals(toOfflineMessage.getToState(), MasterSlaveSMD.States.OFFLINE.name());


    // Now, the old master finish state transition, but has not forward p2p message yet.
    // Then the preference list has changed, so now the new master is different from previously calculated new master
    // but controller should not send S->M to newly calculated master.
    currentStateOutput.setCurrentState(db, p, masterInstance, "OFFLINE");
    event.addAttribute(AttributeName.CURRENT_STATE.name(), currentStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), currentStateOutput);

    String slaveInstance =
        getTopStateInstance(bestPossibleStateOutput.getInstanceStateMap(db, p),
            MasterSlaveSMD.States.SLAVE.name());

    Map<String, String> instanceStateMap = bestPossibleStateOutput.getInstanceStateMap(db, p);
    instanceStateMap.put(newMasterInstance, "SLAVE");
    instanceStateMap.put(slaveInstance, "MASTER");
    bestPossibleStateOutput.setState(db, p, instanceStateMap);

    event.addAttribute(AttributeName.BEST_POSSIBLE_STATE.name(), bestPossibleStateOutput);

    pipeline = new Pipeline("test");
    pipeline.addStage(new MessageGenerationPhase());
    pipeline.addStage(new MessageSelectionStage());
    pipeline.addStage(new IntermediateStateCalcStage());
    pipeline.addStage(new MessageThrottleStage());

    pipeline.handle(event);

    messageOutput =
        event.getAttribute(AttributeName.MESSAGES_SELECTED.name());
    messages = messageOutput.getMessages(db, p);
    Assert.assertEquals(messages.size(), 0);


    // Now, the old master has forwarded the p2p master to previously calculated master,
    // So the state-transition still happened in previously calculated master.
    // Controller will not send S->M to new master.
    currentStateOutput.setPendingMessage(db, p, newMasterInstance, relayMessage);
    event.addAttribute(AttributeName.CURRENT_STATE.name(), currentStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), currentStateOutput);

    event.addAttribute(AttributeName.BEST_POSSIBLE_STATE.name(), bestPossibleStateOutput);
    event.addAttribute(AttributeName.INTERMEDIATE_STATE.name(), bestPossibleStateOutput);


    pipeline = new Pipeline("test");
    pipeline.addStage(new MessageGenerationPhase());
    pipeline.addStage(new MessageSelectionStage());
    pipeline.addStage(new IntermediateStateCalcStage());
    pipeline.addStage(new MessageThrottleStage());

    pipeline.handle(event);

    messageOutput =
        event.getAttribute(AttributeName.MESSAGES_SELECTED.name());
    messages = messageOutput.getMessages(db, p);
    Assert.assertEquals(messages.size(), 0);


    // now, the previous calculated master completed the state transition and deleted the p2p message.
    // Controller should drop this master first.
    currentStateOutput =
        populateCurrentStateFromBestPossible(bestPossibleStateOutput);
    currentStateOutput.setCurrentState(db, p, newMasterInstance, "MASTER");
    currentStateOutput.setCurrentState(db, p, slaveInstance, "SLAVE");

    event.addAttribute(AttributeName.CURRENT_STATE.name(), currentStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), currentStateOutput);

    pipeline = new Pipeline("test");
    pipeline.addStage(new MessageGenerationPhase());
    pipeline.addStage(new MessageSelectionStage());
    pipeline.addStage(new MessageThrottleStage());

    pipeline.handle(event);

    messageOutput =
        event.getAttribute(AttributeName.MESSAGES_SELECTED.name());
    messages = messageOutput.getMessages(db, p);
    Assert.assertEquals(messages.size(), 1);

    toSlaveMessage = messages.get(0);
    Assert.assertEquals(toSlaveMessage.getTgtName(), newMasterInstance);
    Assert.assertEquals(toSlaveMessage.getFromState(), MasterSlaveSMD.States.MASTER.name());
    Assert.assertEquals(toSlaveMessage.getToState(), MasterSlaveSMD.States.SLAVE.name());
  }

  private void testP2PMessage(ClusterConfig clusterConfig, Boolean p2pMessageEnabled)
      throws Exception {
    Map<String, Resource> resourceMap = getResourceMap(new String[] { db }, numPartition,
        BuiltInStateModelDefinitions.MasterSlave.name(), clusterConfig, null);

    event.addAttribute(AttributeName.RESOURCES.name(), resourceMap);
    event.addAttribute(AttributeName.RESOURCES_TO_REBALANCE.name(), resourceMap);
    event.addAttribute(AttributeName.CURRENT_STATE.name(), new CurrentStateOutput());
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), new CurrentStateOutput());
    event.addAttribute(AttributeName.helixmanager.name(), manager);
    event.addAttribute(AttributeName.ControllerDataProvider.name(),
        new ResourceControllerDataProvider());

    Pipeline pipeline = createPipeline();
    pipeline.handle(event);

    BestPossibleStateOutput bestPossibleStateOutput =
        event.getAttribute(AttributeName.BEST_POSSIBLE_STATE.name());

    CurrentStateOutput currentStateOutput =
        populateCurrentStateFromBestPossible(bestPossibleStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE.name(), currentStateOutput);
    event.addAttribute(AttributeName.CURRENT_STATE_EXCLUDING_UNKNOWN.name(), currentStateOutput);

    Partition p = new Partition(db + "_0");

    String masterInstance = getTopStateInstance(bestPossibleStateOutput.getInstanceStateMap(db, p),
        MasterSlaveSMD.States.MASTER.name());
    Assert.assertNotNull(masterInstance);

    admin.enableInstance(_clusterName, masterInstance, false);
    ResourceControllerDataProvider cache = event.getAttribute(AttributeName.ControllerDataProvider.name());
    cache.notifyDataChange(HelixConstants.ChangeType.INSTANCE_CONFIG);

    pipeline = createPipeline();
    pipeline.handle(event);

    bestPossibleStateOutput = event.getAttribute(AttributeName.BEST_POSSIBLE_STATE.name());

    MessageOutput messageOutput =
        event.getAttribute(AttributeName.MESSAGES_SELECTED.name());
    List<Message> messages = messageOutput.getMessages(db, p);

    Assert.assertEquals(messages.size(), 1);
    Message message = messages.get(0);
    Assert.assertEquals(message.getTgtName(), masterInstance);
    Assert.assertEquals(message.getFromState(), MasterSlaveSMD.States.MASTER.name());
    Assert.assertEquals(message.getToState(), MasterSlaveSMD.States.SLAVE.name());

    if (p2pMessageEnabled) {
      Assert.assertEquals(message.getRelayMessages().entrySet().size(), 1);
      String newMasterInstance =
          getTopStateInstance(bestPossibleStateOutput.getInstanceStateMap(db, p),
              MasterSlaveSMD.States.MASTER.name());

      Message relayMessage = message.getRelayMessage(newMasterInstance);
      Assert.assertNotNull(relayMessage);
      Assert.assertEquals(relayMessage.getMsgSubType(), Message.MessageType.RELAYED_MESSAGE.name());
      Assert.assertEquals(relayMessage.getTgtName(), newMasterInstance);
      Assert.assertEquals(relayMessage.getRelaySrcHost(), masterInstance);
      Assert.assertEquals(relayMessage.getFromState(), MasterSlaveSMD.States.SLAVE.name());
      Assert.assertEquals(relayMessage.getToState(), MasterSlaveSMD.States.MASTER.name());
    } else {
      Assert.assertTrue(message.getRelayMessages().entrySet().isEmpty());
    }
  }

  private String getTopStateInstance(Map<String, String> instanceStateMap, String topState) {
    String masterInstance = null;
    for (Map.Entry<String, String> e : instanceStateMap.entrySet()) {
      if (topState.equals(e.getValue())) {
        masterInstance = e.getKey();
      }
    }

    return masterInstance;
  }

  private CurrentStateOutput populateCurrentStateFromBestPossible(
      BestPossibleStateOutput bestPossibleStateOutput) {
    CurrentStateOutput currentStateOutput = new CurrentStateOutput();
    for (String resource : bestPossibleStateOutput.getResourceStatesMap().keySet()) {
      PartitionStateMap partitionStateMap = bestPossibleStateOutput.getPartitionStateMap(resource);
      for (Partition p : partitionStateMap.partitionSet()) {
        Map<String, String> stateMap = partitionStateMap.getPartitionMap(p);

        for (Map.Entry<String, String> e : stateMap.entrySet()) {
          currentStateOutput.setCurrentState(resource, p, e.getKey(), e.getValue());
        }
      }
    }
    return currentStateOutput;
  }

  private Pipeline createPipeline() {
    Pipeline pipeline = new Pipeline("test");
    pipeline.addStage(new ReadClusterDataStage());
    pipeline.addStage(new BestPossibleStateCalcStage());
    pipeline.addStage(new MessageGenerationPhase());
    pipeline.addStage(new MessageSelectionStage());
    pipeline.addStage(new IntermediateStateCalcStage());
    pipeline.addStage(new MessageThrottleStage());

    return pipeline;
  }
}
