/**
 * 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.curator.framework.recipes.queue;

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

import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.framework.imps.CuratorFrameworkState;
import org.apache.curator.framework.state.ConnectionState;
import org.apache.curator.retry.RetryOneTime;
import org.apache.curator.test.BaseClassForTests;
import org.apache.curator.test.Timing;
import org.apache.curator.utils.CloseableUtils;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.junit.jupiter.api.Test;

import java.util.Arrays;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

public class TestBoundedDistributedQueue extends BaseClassForTests
{
    private static final QueueSerializer<String> serializer = new QueueSerializer<String>()
    {
        @Override
        public byte[] serialize(String item)
        {
            return item.getBytes();
        }

        @Override
        public String deserialize(byte[] bytes)
        {
            return new String(bytes);
        }
    };

    @SuppressWarnings("SynchronizationOnLocalVariableOrMethodParameter")
    @Test
    public void         testMulti() throws Exception
    {
        final String        PATH = "/queue";
        final int           CLIENT_QTY = 4;
        final int           MAX_ITEMS = 10;
        final int           ADD_ITEMS = MAX_ITEMS * 100;

        final QueueConsumer<String>     consumer = new QueueConsumer<String>()
        {
            @Override
            public void consumeMessage(String message) throws Exception
            {
                Thread.sleep(10);
            }

            @Override
            public void stateChanged(CuratorFramework client, ConnectionState newState)
            {
            }
        };

        final Timing                        timing = new Timing();
        final ExecutorService               executor = Executors.newCachedThreadPool();
        ExecutorCompletionService<Void>     completionService = new ExecutorCompletionService<Void>(executor);

        final CuratorFramework              client = CuratorFrameworkFactory.newClient(server.getConnectString(), timing.session(), timing.connection(), new RetryOneTime(1));
        try
        {
            client.start();
            client.create().forPath(PATH);

            final CountDownLatch    isWaitingLatch = new CountDownLatch(1);
            final AtomicBoolean     isDone = new AtomicBoolean(false);
            final List<Integer>     counts = new CopyOnWriteArrayList<Integer>();
            final Object            lock = new Object();
            executor.submit
            (
                new Callable<Void>()
                {
                    @Override
                    public Void call() throws Exception
                    {
                        Watcher     watcher = new Watcher()
                        {
                            @Override
                            public void process(WatchedEvent event)
                            {
                                synchronized(lock)
                                {
                                    lock.notifyAll();
                                }
                            }
                        };

                        while ( !Thread.currentThread().isInterrupted() && client.getState() == CuratorFrameworkState.STARTED && !isDone.get() )
                        {
                            synchronized(lock)
                            {
                                int     size = client.getChildren().usingWatcher(watcher).forPath(PATH).size();
                                counts.add(size);
                                isWaitingLatch.countDown();
                                lock.wait();
                            }
                        }
                        return null;
                    }
                }
            );
            isWaitingLatch.await();

            for ( int i = 0; i < CLIENT_QTY; ++i )
            {
                final int       index = i;
                completionService.submit
                (
                    new Callable<Void>()
                    {
                        @Override
                        public Void call() throws Exception
                        {
                            CuratorFramework            client = null;
                            DistributedQueue<String>    queue = null;

                            try
                            {
                                client = CuratorFrameworkFactory.newClient(server.getConnectString(), timing.session(), timing.connection(), new RetryOneTime(1));
                                client.start();
                                queue = QueueBuilder.builder(client, consumer, serializer, PATH).executor(executor).maxItems(MAX_ITEMS).putInBackground(false).lockPath("/locks").buildQueue();
                                queue.start();

                                for ( int i = 0; i < ADD_ITEMS; ++i )
                                {
                                    queue.put("" + index + "-" + i);
                                }
                            }
                            finally
                            {
                                CloseableUtils.closeQuietly(queue);
                                CloseableUtils.closeQuietly(client);
                            }
                            return null;
                        }
                    }
                );
            }

            for ( int i = 0; i < CLIENT_QTY; ++i )
            {
                completionService.take().get();
            }

            isDone.set(true);
            synchronized(lock)
            {
                lock.notifyAll();
            }

            for ( int count : counts )
            {
                assertTrue(count <= (MAX_ITEMS * CLIENT_QTY), counts.toString());
            }
        }
        finally
        {
            executor.shutdownNow();
            CloseableUtils.closeQuietly(client);
        }
    }

    @Test
    public void         testSimple() throws Exception
    {
        Timing                      timing = new Timing();
        DistributedQueue<String>    queue = null;
        CuratorFramework            client = CuratorFrameworkFactory.newClient(server.getConnectString(), timing.session(), timing.connection(), new RetryOneTime(1));
        try
        {
            client.start();

            final List<String>          messages = new CopyOnWriteArrayList<String>();
            final CountDownLatch        latch = new CountDownLatch(2);
            final Semaphore             semaphore = new Semaphore(0);
            QueueConsumer<String>       consumer = new QueueConsumer<String>()
            {
                @Override
                public void consumeMessage(String message) throws Exception
                {
                    messages.add(message);
                    semaphore.acquire();
                }

                @Override
                public void stateChanged(CuratorFramework client, ConnectionState newState)
                {
                }
            };
            queue = QueueBuilder.builder(client, consumer, serializer, "/queue").executor(Executors.newSingleThreadExecutor()).maxItems(1).buildQueue();
            queue.start();

            QueuePutListener<String>    listener = new QueuePutListener<String>()
            {
                @Override
                public void putCompleted(String item)
                {
                    latch.countDown();
                }

                @Override
                public void putMultiCompleted(MultiItem<String> items)
                {
                }
            };
            queue.getPutListenerContainer().addListener(listener);

            assertTrue(queue.put("1", timing.milliseconds(), TimeUnit.MILLISECONDS));   // should end up in consumer
            assertTrue(queue.put("2", timing.milliseconds(), TimeUnit.MILLISECONDS));   // should sit blocking in DistributedQueue
            assertTrue(timing.awaitLatch(latch));
            timing.sleepABit();
            assertFalse(queue.put("3", timing.multiple(.5).milliseconds(), TimeUnit.MILLISECONDS));

            semaphore.release(100);
            assertTrue(queue.put("3", timing.milliseconds(), TimeUnit.MILLISECONDS));
            assertTrue(queue.put("4", timing.milliseconds(), TimeUnit.MILLISECONDS));
            assertTrue(queue.put("5", timing.milliseconds(), TimeUnit.MILLISECONDS));

            for ( int i = 0; i < 5; ++i )
            {
                if ( messages.size() == 3 )
                {
                    break;
                }
                timing.sleepABit();
            }
            timing.sleepABit();

            assertEquals(messages, Arrays.asList("1", "2", "3", "4", "5"));
        }
        finally
        {
            CloseableUtils.closeQuietly(queue);
            CloseableUtils.closeQuietly(client);
        }
    }
}
