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/**
 * 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.activemq.artemis.jms.example;

import java.util.Hashtable;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.naming.InitialContext;

import org.apache.activemq.artemis.api.core.TransportConfiguration;
import org.apache.activemq.artemis.api.core.client.ClusterTopologyListener;
import org.apache.activemq.artemis.api.core.client.TopologyMember;
import org.apache.activemq.artemis.common.example.ActiveMQExample;
import org.apache.activemq.artemis.jms.client.ActiveMQConnection;
import org.apache.activemq.artemis.jms.client.ActiveMQConnectionFactory;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

/**
 * A simple example that demonstrates server side load-balancing of messages between the queue instances on different
 * nodes of the cluster.
 *
 */
public class HAPolicyAutoBackupExample extends ActiveMQExample
{
   public static void main(final String[] args)
   {
      new HAPolicyAutoBackupExample().run(args);
   }

   @Override
   public boolean runExample() throws Exception
   {
      Connection connection0 = null;

      Connection connection1 = null;

      InitialContext ic0 = null;

      InitialContext ic1 = null;

      try
      {
         // Step 1. Get an initial context for looking up JNDI from server 0 and 1
         Hashtable properties = new Hashtable();
         properties.put("java.naming.factory.initial", "org.apache.activemq.artemis.jndi.ActiveMQInitialContextFactory");
         properties.put("connectionFactory.ConnectionFactory", args[0] + "?ha=true&retryInterval=1000&retryIntervalMultiplier=1.0&reconnectAttempts=-1");
         properties.put("queue.queue/exampleQueue", "exampleQueue");
         ic0 = new InitialContext(properties);

         properties = new Hashtable();
         properties.put("java.naming.factory.initial", "org.apache.activemq.artemis.jndi.ActiveMQInitialContextFactory");
         properties.put("connectionFactory.ConnectionFactory", args[1] + "?ha=true&retryInterval=1000&retryIntervalMultiplier=1.0&reconnectAttempts=-1");
         ic1 = new InitialContext(properties);

         // Step 2. Look-up the JMS Queue object from JNDI
         Queue queue = (Queue) ic0.lookup("queue/exampleQueue");

         // Step 3. Look-up a JMS Connection Factory object from JNDI on server 0 and 1
         ConnectionFactory cf0 = (ConnectionFactory) ic0.lookup("ConnectionFactory");
         ConnectionFactory cf1 = (ConnectionFactory) ic1.lookup("ConnectionFactory");

         // Step 6. We create JMS Connections to server 0 and 1
         connection0 = cf0.createConnection();
         connection1 = cf1.createConnection();

         // step 7. wait for the backups to start replication
         waitForBackups(cf0, 2);

         // Step 8. We create JMS Sessions on server 0 and 1
         Session session0 = connection0.createSession(false, Session.AUTO_ACKNOWLEDGE);
         Session session1 = connection1.createSession(false, Session.AUTO_ACKNOWLEDGE);

         // Step 9. We start the connections to ensure delivery occurs on them
         connection0.start();
         connection1.start();

         // Step 10. We create JMS MessageConsumer objects on server 0 and server 1
         MessageConsumer consumer0 = session0.createConsumer(queue);
         MessageConsumer consumer1 = session1.createConsumer(queue);


         // Step 11. We create a JMS MessageProducer object on server 0
         MessageProducer producer = session0.createProducer(queue);

         // Step 12. We send some messages to server 0

         final int numMessages = 10;

         for (int i = 0; i < numMessages; i++)
         {
            TextMessage message = session0.createTextMessage("This is text message " + i);

            producer.send(message);

            System.out.println("Sent message: " + message.getText());
         }

         // Step 13. We now consume half the messages on consumer0
         // note that the other half of the messages will have been sent to server1 for consumer1
         for (int i = 0; i < numMessages / 2; i++)
         {
            TextMessage message0 = (TextMessage) consumer0.receive(5000);

            System.out.println("Got message: " + message0.getText() + " from node 0");
         }

         // Step 14.now kill server1, messages will be scaled down to server0
         killServer(1);

         // Step 15.close the consumer so it doesnt get any messages
         consumer1.close();

         // Step 16. we now receive the messages that were on server1 but were scaled down to server0
         for (int i = 0; i < numMessages / 2; i++)
         {
            TextMessage message0 = (TextMessage) consumer0.receive(5000);

            System.out.println("Got message: " + message0.getText() + " from node 1");
         }

         return true;
      }
      finally
      {
         // Step 17. Be sure to close our resources!

         if (connection0 != null)
         {
            connection0.close();
         }

         if (connection1 != null)
         {
            connection1.close();
         }
      }
   }

   private void waitForBackups(ConnectionFactory cf0, int backups) throws InterruptedException
   {
      final CountDownLatch latch = new CountDownLatch(backups);
         ((ActiveMQConnectionFactory) cf0).getServerLocator().addClusterTopologyListener(new ClusterTopologyListener()
      {
         List backups = new ArrayList();
         @Override
         public void nodeUP(TopologyMember member, boolean last)
         {
            if (member.getBackup() != null && !backups.contains(member.getBackup()))
            {
               backups.add(member.getBackup());
               latch.countDown();
            }
         }

         @Override
         public void nodeDown(long eventUID, String nodeID)
         {
         }
      });
      latch.await(30000, TimeUnit.MILLISECONDS);
   }

}