/*
 * Copyright 2018 Mitsunori Komatsu (komamitsu)
 *
 * Licensed 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.komamitsu.fluency.fluentd.ingester.sender.heartbeat;

import org.junit.jupiter.api.Test;

import java.io.IOException;
import java.net.SocketAddress;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicInteger;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;

class UDPHeartbeaterTest
{
    @Test
    void testUDPHeartbeaterUp()
            throws IOException, InterruptedException
    {
        final CountDownLatch latch = new CountDownLatch(2);
        final DatagramChannel datagramChannel = DatagramChannel.open();
        datagramChannel.socket().bind(null);
        Executors.newSingleThreadExecutor().execute(() -> {
            try {
                ByteBuffer byteBuffer = ByteBuffer.allocate(8);
                SocketAddress socketAddress = datagramChannel.receive(byteBuffer);
                datagramChannel.send(ByteBuffer.allocate(0), socketAddress);
                latch.countDown();
            }
            catch (IOException e) {
                e.printStackTrace();
            }
        });

        UDPHeartbeater.Config config = new UDPHeartbeater.Config();
        config.setPort(datagramChannel.socket().getLocalPort());
        config.setIntervalMillis(500);
        try (UDPHeartbeater heartbeater = new UDPHeartbeater(config)) {
            final AtomicInteger pongCounter = new AtomicInteger();
            final AtomicInteger failureCounter = new AtomicInteger();
            heartbeater.setCallback(new Heartbeater.Callback()
            {
                @Override
                public void onHeartbeat()
                {
                    pongCounter.incrementAndGet();
                    latch.countDown();
                }

                @Override
                public void onFailure(Throwable cause)
                {
                    failureCounter.incrementAndGet();
                }
            });
            heartbeater.start();
            assertTrue(latch.await(5, TimeUnit.SECONDS));
            assertTrue(0 < pongCounter.get() && pongCounter.get() < 3);
            assertEquals(0, failureCounter.get());
        }
    }

    @Test
    void testUDPHeartbeaterDown()
            throws IOException, InterruptedException
    {
        final DatagramChannel datagramChannel = DatagramChannel.open();
        datagramChannel.socket().bind(null);
        int localPort = datagramChannel.socket().getLocalPort();
        datagramChannel.close();

        UDPHeartbeater.Config config = new UDPHeartbeater.Config();
        config.setPort(localPort);
        config.setIntervalMillis(500);
        try (UDPHeartbeater heartbeater = new UDPHeartbeater(config)) {
            final AtomicInteger pongCounter = new AtomicInteger();
            heartbeater.setCallback(new Heartbeater.Callback()
            {
                @Override
                public void onHeartbeat()
                {
                    pongCounter.incrementAndGet();
                }

                @Override
                public void onFailure(Throwable cause)
                {
                }
            });
            heartbeater.start();
            TimeUnit.SECONDS.sleep(1);
            assertEquals(0, pongCounter.get());
        }
    }
}
