/*
 * 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.flink.runtime.leaderelection;

import org.apache.flink.configuration.ConfigConstants;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.runtime.leaderretrieval.LeaderRetrievalService;
import org.apache.flink.runtime.testingUtils.TestingCluster;
import scala.Option;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

/**
 * A testing cluster which allows to manually trigger grantLeadership and notifyRetrievalListener
 * events. The grantLeadership event assigns the specified JobManager the leadership. The
 * notifyRetrievalListener notifies all listeners that the specified JobManager (index) has been
 * granted the leadership.
 */
public class LeaderElectionRetrievalTestingCluster extends TestingCluster {

	private final Configuration userConfiguration;
	private final boolean useSingleActorSystem;

	public List<TestingLeaderElectionService> leaderElectionServices;
	public List<TestingLeaderRetrievalService> leaderRetrievalServices;

	private int leaderIndex = -1;

	public LeaderElectionRetrievalTestingCluster(
			Configuration userConfiguration,
			boolean singleActorSystem,
			boolean synchronousDispatcher) {
		super(userConfiguration, singleActorSystem, synchronousDispatcher);

		this.userConfiguration = userConfiguration;
		this.useSingleActorSystem = singleActorSystem;

		leaderElectionServices = new ArrayList<TestingLeaderElectionService>();
		leaderRetrievalServices = new ArrayList<TestingLeaderRetrievalService>();
	}

	@Override
	public Configuration userConfiguration() {
		return this.userConfiguration;
	}

	@Override
	public boolean useSingleActorSystem() {
		return useSingleActorSystem;
	}

	@Override
	public Option<LeaderElectionService> createLeaderElectionService() {
		leaderElectionServices.add(new TestingLeaderElectionService());

		LeaderElectionService result = leaderElectionServices.get(leaderElectionServices.size() - 1);

		return Option.apply(result);
	}

	@Override
	public LeaderRetrievalService createLeaderRetrievalService() {
		leaderRetrievalServices.add(new TestingLeaderRetrievalService());

		return leaderRetrievalServices.get(leaderRetrievalServices.size() - 1);
	}

	@Override
	public int getNumberOfJobManagers() {
		return this.originalConfiguration().getInteger(
				ConfigConstants.LOCAL_NUMBER_JOB_MANAGER,
				ConfigConstants.DEFAULT_LOCAL_NUMBER_JOB_MANAGER);
	}

	public void grantLeadership(int index, UUID leaderSessionID) {
		if(leaderIndex >= 0) {
			// first revoke leadership
			leaderElectionServices.get(leaderIndex).notLeader();
		}

		// make the JM with index the new leader
		leaderElectionServices.get(index).isLeader(leaderSessionID);

		leaderIndex = index;
	}

	public void notifyRetrievalListeners(int index, UUID leaderSessionID) {
		String address = jobManagerActors().get().apply(index).path().toString();

		for(TestingLeaderRetrievalService service: leaderRetrievalServices) {
			service.notifyListener(address, leaderSessionID);
		}
	}

	public void revokeLeadership() {
		if (leaderIndex >= 0) {
			leaderElectionServices.get(leaderIndex).notLeader();
			leaderIndex = -1;
		}
	}
}