/**
 * 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.network;

import javax.jms.Connection;
import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.Session;
import javax.management.ObjectName;
import java.net.URI;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.broker.BrokerService;
import org.apache.activemq.broker.TransportConnector;
import org.apache.activemq.broker.jmx.BrokerViewMBean;
import org.apache.activemq.broker.jmx.DurableSubscriptionViewMBean;
import org.apache.activemq.store.PersistenceAdapter;
import org.apache.commons.lang.ArrayUtils;
import org.fusesource.hawtdispatch.Dispatch;
import org.fusesource.mqtt.client.BlockingConnection;
import org.fusesource.mqtt.client.MQTT;
import org.fusesource.mqtt.client.QoS;
import org.fusesource.mqtt.client.Topic;
import org.fusesource.mqtt.client.Tracer;
import org.fusesource.mqtt.codec.MQTTFrame;
import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class MQTTNetworkOfBrokersFailoverTest extends NetworkTestSupport {

   private static final Logger LOG = LoggerFactory.getLogger(MQTTNetworkOfBrokersFailoverTest.class);
   private int localBrokerMQTTPort = -1;
   private int remoteBrokerMQTTPort = -1;

   @Override
   protected void setUp() throws Exception {
      useJmx = true;
      super.setUp();

      URI ncUri = new URI("static:(" + connector.getConnectUri().toString() + ")");
      NetworkConnector nc = new DiscoveryNetworkConnector(ncUri);
      nc.setDuplex(true);
      remoteBroker.addNetworkConnector(nc);
      nc.start();

      // mqtt port should have been assigned by now
      assertFalse(localBrokerMQTTPort == -1);
      assertFalse(remoteBrokerMQTTPort == -1);
   }

   @Override
   protected void tearDown() throws Exception {
      if (remoteBroker.isStarted()) {
         remoteBroker.stop();
         remoteBroker.waitUntilStopped();
      }
      if (broker.isStarted()) {
         broker.stop();
         broker.waitUntilStopped();
      }
      super.tearDown();
   }

   @Test
   public void testNoStaleSubscriptionAcrossNetwork() throws Exception {

      // before we get started, we want an async way to be able to know when
      // the durable consumer has been networked so we can assert that it indeed
      // would have a durable subscriber. for example, when we subscribe on remote broker,
      // a network-sub would be created on local broker and we want to listen for when that
      // even happens. we do that with advisory messages and a latch:
      CountDownLatch consumerNetworked = listenForConsumersOn(broker);

      // create a subscription with Clean == 0 (durable sub for QoS==1 && QoS==2)
      // on the remote broker. this sub should still be there after we disconnect
      MQTT remoteMqtt = createMQTTTcpConnection("foo", false, remoteBrokerMQTTPort);
      BlockingConnection remoteConn = remoteMqtt.blockingConnection();
      remoteConn.connect();
      remoteConn.subscribe(new Topic[]{new Topic("foo/bar", QoS.AT_LEAST_ONCE)});

      assertTrue("No destination detected!", consumerNetworked.await(1, TimeUnit.SECONDS));
      assertQueueExistsOn(remoteBroker, "Consumer.foo_AT_LEAST_ONCE.VirtualTopic.foo.bar");
      assertQueueExistsOn(broker, "Consumer.foo_AT_LEAST_ONCE.VirtualTopic.foo.bar");
      remoteConn.disconnect();

      // now we reconnect the same sub on the local broker, again with clean==0
      MQTT localMqtt = createMQTTTcpConnection("foo", false, localBrokerMQTTPort);
      BlockingConnection localConn = localMqtt.blockingConnection();
      localConn.connect();
      localConn.subscribe(new Topic[]{new Topic("foo/bar", QoS.AT_LEAST_ONCE)});

      // now let's connect back up to remote broker and send a message
      remoteConn = remoteMqtt.blockingConnection();
      remoteConn.connect();
      remoteConn.publish("foo/bar", "Hello, World!".getBytes(), QoS.AT_LEAST_ONCE, false);

      // now we should see that message on the local broker because the subscription
      // should have been properly networked... we'll give a sec of grace for the
      // networking and forwarding to have happened properly
      org.fusesource.mqtt.client.Message msg = localConn.receive(100, TimeUnit.SECONDS);
      assertNotNull(msg);
      msg.ack();
      String response = new String(msg.getPayload());
      assertEquals("Hello, World!", response);
      assertEquals("foo/bar", msg.getTopic());

      // Now... we SHOULD NOT see a message on the remote broker because we already
      // consumed it on the local broker... having the same message on the remote broker
      // would effectively give us duplicates in a distributed topic scenario:
      remoteConn.subscribe(new Topic[]{new Topic("foo/bar", QoS.AT_LEAST_ONCE)});
      msg = remoteConn.receive(500, TimeUnit.MILLISECONDS);
      assertNull("We have duplicate messages across the cluster for a distributed topic", msg);
   }

   private CountDownLatch listenForConsumersOn(BrokerService broker) throws Exception {
      final CountDownLatch latch = new CountDownLatch(1);

      URI brokerUri = broker.getVmConnectorURI();

      final ActiveMQConnectionFactory cf = new ActiveMQConnectionFactory(brokerUri.toASCIIString());
      final Connection connection = cf.createConnection();
      connection.start();
      final Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
      Destination dest = session.createTopic("ActiveMQ.Advisory.Consumer.Queue.Consumer.foo:AT_LEAST_ONCE.VirtualTopic.foo.bar");
      MessageConsumer consumer = session.createConsumer(dest);
      consumer.setMessageListener(new MessageListener() {
         @Override
         public void onMessage(Message message) {
            latch.countDown();
            // shutdown this connection
            Dispatch.getGlobalQueue().execute(new Runnable() {
               @Override
               public void run() {
                  try {
                     session.close();
                     connection.close();
                  } catch (JMSException e) {
                     e.printStackTrace();
                  }
               }
            });
         }
      });

      return latch;
   }

   private void assertQueueExistsOn(BrokerService broker, String queueName) throws Exception {
      BrokerViewMBean brokerView = broker.getAdminView();
      ObjectName[] queueNames = brokerView.getQueues();
      assertEquals(1, queueNames.length);

      assertTrue(queueNames[0].toString().contains(queueName));
   }

   @SuppressWarnings("unused")
   private void assertOneDurableSubOn(BrokerService broker, String subName) throws Exception {
      BrokerViewMBean brokerView = broker.getAdminView();
      ObjectName[] activeDurableSubs = brokerView.getDurableTopicSubscribers();
      ObjectName[] inactiveDurableSubs = brokerView.getInactiveDurableTopicSubscribers();
      ObjectName[] allDurables = (ObjectName[]) ArrayUtils.addAll(activeDurableSubs, inactiveDurableSubs);
      assertEquals(1, allDurables.length);

      // at this point our assertions should prove that we have only on durable sub
      DurableSubscriptionViewMBean durableSubView = (DurableSubscriptionViewMBean) broker.getManagementContext().newProxyInstance(allDurables[0], DurableSubscriptionViewMBean.class, true);

      assertEquals(subName, durableSubView.getClientId());
   }

   @Override
   protected BrokerService createBroker() throws Exception {
      BrokerService broker = super.createBroker();
      broker.setPersistent(true);
      broker.setBrokerName("local");
      broker.setDataDirectory("target/activemq-data");
      broker.setDeleteAllMessagesOnStartup(true);
      TransportConnector tc = broker.addConnector(getDefaultMQTTTransportConnectorUri());
      localBrokerMQTTPort = tc.getConnectUri().getPort();
      return broker;
   }

   @Override
   protected BrokerService createRemoteBroker(PersistenceAdapter persistenceAdapter) throws Exception {
      BrokerService broker = super.createRemoteBroker(persistenceAdapter);
      broker.setPersistent(true);
      broker.setDeleteAllMessagesOnStartup(true);
      broker.setDataDirectory("target/activemq-data");
      TransportConnector tc = broker.addConnector(getDefaultMQTTTransportConnectorUri());
      remoteBrokerMQTTPort = tc.getConnectUri().getPort();
      return broker;
   }

   private String getDefaultMQTTTransportConnectorUri() {
      return "mqtt://localhost:0?transport.subscriptionStrategy=mqtt-virtual-topic-subscriptions";
   }

   private MQTT createMQTTTcpConnection(String clientId, boolean clean, int port) throws Exception {
      MQTT mqtt = new MQTT();
      mqtt.setConnectAttemptsMax(1);
      mqtt.setReconnectAttemptsMax(0);
      mqtt.setTracer(createTracer());
      if (clientId != null) {
         mqtt.setClientId(clientId);
      }
      mqtt.setCleanSession(clean);
      mqtt.setHost("localhost", port);
      return mqtt;
   }

   protected Tracer createTracer() {
      return new Tracer() {
         @Override
         public void onReceive(MQTTFrame frame) {
            LOG.info("Client Received:\n" + frame);
         }

         @Override
         public void onSend(MQTTFrame frame) {
            LOG.info("Client Sent:\n" + frame);
         }

         @Override
         public void debug(String message, Object... args) {
            LOG.info(String.format(message, args));
         }
      };
   }
}
