/*
 * 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.test.runtime;

import akka.actor.ActorSystem;
import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.configuration.ConfigConstants;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.TaskManagerOptions;
import org.apache.flink.runtime.akka.AkkaUtils;
import org.apache.flink.runtime.minicluster.LocalFlinkMiniCluster;
import org.apache.flink.test.testdata.WordCountData;

import org.apache.flink.test.util.TestBaseUtils;
import org.apache.flink.util.Collector;
import org.apache.flink.util.NetUtils;
import org.apache.flink.util.TestLogger;

import org.junit.Test;

import scala.Some;

import java.io.IOException;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.util.Enumeration;
import java.util.List;

import static org.junit.Assert.*;

@SuppressWarnings("serial")
public class IPv6HostnamesITCase extends TestLogger {
	
	@Test
	public void testClusterWithIPv6host() {

		final Inet6Address ipv6address = getLocalIPv6Address();
		if (ipv6address == null) {
			System.err.println("--- Cannot find a non-loopback local IPv6 address that Akka/Netty can bind to; skipping IPv6HostnamesITCase");
			return;
		}

		
		
		LocalFlinkMiniCluster flink = null;
		try {
			final String addressString = ipv6address.getHostAddress();
			log.info("Test will use IPv6 address " + addressString + " for connection tests");
			
			Configuration conf = new Configuration();
			conf.setString(ConfigConstants.JOB_MANAGER_IPC_ADDRESS_KEY, addressString);
			conf.setString(ConfigConstants.TASK_MANAGER_HOSTNAME_KEY, addressString);
			conf.setInteger(ConfigConstants.LOCAL_NUMBER_TASK_MANAGER, 2);
			conf.setInteger(ConfigConstants.TASK_MANAGER_NUM_TASK_SLOTS, 2);
			conf.setLong(TaskManagerOptions.MANAGED_MEMORY_SIZE, 16L);
			
			flink = new LocalFlinkMiniCluster(conf, false);
			flink.start();

			ExecutionEnvironment env = ExecutionEnvironment.createRemoteEnvironment(addressString, flink.getLeaderRPCPort());
			env.setParallelism(4);
			env.getConfig().disableSysoutLogging();
			
			// get input data
			DataSet<String> text = env.fromElements(WordCountData.TEXT.split("\n"));

			DataSet<Tuple2<String, Integer>> counts =text
					.flatMap(new FlatMapFunction<String, Tuple2<String, Integer>>() {
						@Override
						public void flatMap(String value, Collector<Tuple2<String, Integer>> out) throws Exception {
							for (String token : value.toLowerCase().split("\\W+")) {
								if (token.length() > 0) {
									out.collect(new Tuple2<String, Integer>(token, 1));
								}
							}
						}
					})
					.groupBy(0).sum(1);

			List<Tuple2<String, Integer>> result = counts.collect();

			TestBaseUtils.compareResultAsText(result, WordCountData.COUNTS_AS_TUPLES);
		}
		catch (Exception e) {
			e.printStackTrace();
			fail(e.getMessage());
		}
		finally {
			if (flink != null) {
				flink.shutdown();
			}
		}
	}
	
	
	private Inet6Address getLocalIPv6Address() {
		try {
			Enumeration<NetworkInterface> e = NetworkInterface.getNetworkInterfaces();
			while (e.hasMoreElements()) {
				NetworkInterface netInterface = e.nextElement();

				// for each address of the network interface
				Enumeration<InetAddress> ee = netInterface.getInetAddresses();
				while (ee.hasMoreElements()) {
					InetAddress addr = ee.nextElement();
					
					
					if (addr instanceof Inet6Address && (!addr.isLoopbackAddress()) && (!addr.isAnyLocalAddress())) {
						// see if it is possible to bind to the address
						InetSocketAddress socketAddress = new InetSocketAddress(addr, 0);
						
						try {
							log.info("Considering address " + addr);
							
							// test whether we can bind a socket to that address
							log.info("Testing whether sockets can bind to " + addr);
							ServerSocket sock = new ServerSocket();
							sock.bind(socketAddress);
							sock.close();

							// test whether Akka's netty can bind to the address
							log.info("Testing whether Akka can use " + addr);
							int port = NetUtils.getAvailablePort();
							ActorSystem as = AkkaUtils.createActorSystem(
									new Configuration(),
									new Some<scala.Tuple2<String, Object>>(new scala.Tuple2<String, Object>(addr.getHostAddress(), port)));
							as.shutdown();

							log.info("Using address " + addr);
							return (Inet6Address) addr;
						}
						catch (IOException ignored) {
							// fall through the loop
						}
					}
				}
			}
			
			return null;
		}
		catch (Exception e) {
			return null;
		}
	}
}