/*
    * Copyright (C) 2013 4th Line GmbH, Switzerland
    *
    * The contents of this file are subject to the terms of either the GNU
    * Lesser General Public License Version 2 or later ("LGPL") or the
    * Common Development and Distribution License Version 1 or later
    * ("CDDL") (collectively, the "License"). You may not use this file
    * except in compliance with the License. See LICENSE.txt for more
    * information.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   */
  
  package org.fourthline.cling.protocol.sync;
  
  import java.util.logging.Logger;
  import org.fourthline.cling.UpnpService;
  import org.fourthline.cling.model.gena.LocalGENASubscription;
  import org.fourthline.cling.model.message.StreamResponseMessage;
  import org.fourthline.cling.model.message.gena.OutgoingEventRequestMessage;
  import org.fourthline.cling.model.types.UnsignedIntegerFourBytes;
  import org.fourthline.cling.protocol.SendingSync;
  import org.fourthline.cling.transport.RouterException;
  
  import java.net.URL;
  
  /**
   * Sending GENA event messages to remote subscribers.
   * <p>
   * Any {@link org.fourthline.cling.model.gena.LocalGENASubscription} instantiates and executes this protocol
   * when the state of a local service changes. However, a remote subscriber might require event
   * notification messages on more than one callback URL, so this protocol potentially sends
   * many messages. What is returned is always the last response, that is, the response for the
   * message sent to the last callback URL in the list of the subscriber.
   * </p>
   *
   * @author Christian Bauer
   */
  public class SendingEvent extends SendingSync<OutgoingEventRequestMessage, StreamResponseMessage> {
  
      final private static Logger log = Logger.getLogger(SendingEvent.class.getName());
  
      final protected String subscriptionId;
      final protected OutgoingEventRequestMessage[] requestMessages;
      final protected UnsignedIntegerFourBytes currentSequence;
  
      public SendingEvent(UpnpService upnpService, LocalGENASubscription subscription) {
          super(upnpService, null); // Special case, we actually need to send several messages to each callback URL
  
          // TODO: Ugly design! It is critical (concurrency) that we prepare the event messages here, in the constructor thread!
  
          subscriptionId = subscription.getSubscriptionId();
  
          requestMessages = new OutgoingEventRequestMessage[subscription.getCallbackURLs().size()];
          int i = 0;
          for (URL url : subscription.getCallbackURLs()) {
              requestMessages[i] = new OutgoingEventRequestMessage(subscription, url);
              getUpnpService().getConfiguration().getGenaEventProcessor().writeBody(requestMessages[i]);
              i++;
          }
  
          currentSequence = subscription.getCurrentSequence();
  
          // Always increment sequence now, as (its value) has already been set on the headers and the
          // next event will use the incremented value
          subscription.incrementSequence();
      }
  
      protected StreamResponseMessage executeSync() throws RouterException {
  
          log.fine("Sending event for subscription: " + subscriptionId);
  
          StreamResponseMessage lastResponse = null;
  
          for (OutgoingEventRequestMessage requestMessage : requestMessages) {
  
              if (currentSequence.getValue() == 0) {
                  log.fine("Sending initial event message to callback URL: " + requestMessage.getUri());
              } else {
                  log.fine("Sending event message '"+currentSequence+"' to callback URL: " + requestMessage.getUri());
              }
  
  
              // Send request
              lastResponse = getUpnpService().getRouter().send(requestMessage);
              log.fine("Received event callback response: " + lastResponse);
  
          }
  
          // It's not really used, so just return the last one - we have only one callback URL most of the
          // time anyway
          return lastResponse;
  
      }
  }