/**
 * 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.security;

import javax.jms.Connection;
import javax.jms.JMSException;
import java.net.URI;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;

import org.apache.activemq.ActiveMQConnectionFactory;
import org.apache.activemq.JmsTestSupport;
import org.apache.activemq.broker.BrokerFactory;
import org.apache.activemq.broker.BrokerService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The configuration is set to except a maximum of 2 concurrent connections
 * As the exception is deliberately ignored, the ActiveMQConnection would continue to
 * attempt to connect unless the connection's transport was also stopped on an error.
 * <br>
 * As the maximum connections allowed is 2, no more connections would be allowed unless
 * the transport was adequately destroyed on the broker side.
 */

public class DoSTest extends JmsTestSupport {

   private static final Logger LOG = LoggerFactory.getLogger(DoSTest.class);

   public void testInvalidAuthentication() throws Throwable {

      // with failover reconnect, we don't expect this thread to complete
      // but periodically the failure changes from ExceededMaximumConnectionsException on the broker
      // side to a SecurityException.
      // A failed to authenticated but idle connection (dos style) is aborted by the inactivity monitor
      // since useKeepAlive=false

      final AtomicBoolean done = new AtomicBoolean(false);
      Thread thread = new Thread() {
         Connection connection = null;

         @Override
         public void run() {
            for (int i = 0; i < 1000 && !done.get(); i++) {
               ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory();
               try {
                  // Bad password
                  connection = factory.createConnection("bad", "krap");
                  connection.start();
                  fail("Expected exception.");
               } catch (JMSException e) {
                  // ignore exception and don't close
                  e.printStackTrace();
               }
            }
         }
      };

      thread.start();

      // run dos for a while
      TimeUnit.SECONDS.sleep(10);

      LOG.info("trying genuine connection ...");
      // verify a valid connection can work with one of the 2 allowed connections provided it is eager!
      // it could take a while as it is competing with the three other reconnect threads.
      // wonder if it makes sense to serialise these reconnect attempts on an executor
      ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory("failover:(tcp://127.0.0.1:61616)?useExponentialBackOff=false&reconnectDelay=10");
      Connection goodConnection = factory.createConnection("user", "password");
      goodConnection.start();
      goodConnection.close();

      LOG.info("giving up on DOS");
      done.set(true);
   }

   @Override
   protected BrokerService createBroker() throws Exception {
      return createBroker("org/apache/activemq/security/dos-broker.xml");
   }

   protected BrokerService createBroker(String uri) throws Exception {
      LOG.info("Loading broker configuration from the classpath with URI: " + uri);
      return BrokerFactory.createBroker(new URI("xbean:" + uri));
   }

}
