/**
  * Adds a specific <tt>Subscription</tt> to the list of subscriptions managed by this instance
  * only if another <tt>Subscription</tt> with the same subscription <tt>Address</tt>/Request URI
  * and id tag of its associated Event header does not exist in the list.
  *
  * @param subscription the new <tt>Subscription</tt> to be added to the list of subscriptions
  *     managed by this instance if there is no other <tt>Subscription</tt> in the list which has
  *     the same subscription <tt>Address</tt>/Request URI and id tag of its Event header
  * @throws OperationFailedException if we fail constructing or sending the subscription request
  */
 public void poll(Subscription subscription) throws OperationFailedException {
   if (getSubscription(subscription.getAddress(), subscription.getEventId()) == null)
     subscribe(subscription);
 }
  /**
   * Implements {@link MethodProcessor#processResponse(ResponseEvent)}. Handles only responses to
   * SUBSCRIBE requests because they are the only requests concerning event package subscribers (and
   * the only requests sent by them, for that matter) and if the processing of a given response
   * requires event package-specific handling, delivers the response to the matching
   * <tt>Subscription</tt> instance. Examples of such event package-specific handling include
   * letting the respective <tt>Subscription</tt> handle the success or failure in the establishment
   * of a subscription.
   *
   * @param responseEvent a <tt>ResponseEvent</tt> specifying the SIP <tt>Response</tt> to be
   *     processed
   * @return <tt>true</tt> if the SIP <tt>Response</tt> specified by <tt>responseEvent</tt> was
   *     processed; otherwise, <tt>false</tt>
   */
  @Override
  public boolean processResponse(ResponseEvent responseEvent) {
    Response response = responseEvent.getResponse();

    CSeqHeader cseqHeader = (CSeqHeader) response.getHeader(CSeqHeader.NAME);
    if (cseqHeader == null) {
      logger.error("An incoming response did not contain a CSeq header");
      return false;
    }
    if (!Request.SUBSCRIBE.equals(cseqHeader.getMethod())) return false;

    ClientTransaction clientTransaction = responseEvent.getClientTransaction();
    Request request = clientTransaction.getRequest();

    /*
     * Don't handle responses to requests not coming from this event
     * package.
     */
    if (request != null) {
      EventHeader eventHeader = (EventHeader) request.getHeader(EventHeader.NAME);
      if ((eventHeader == null) || !eventPackage.equalsIgnoreCase(eventHeader.getEventType()))
        return false;
    }

    // Find the subscription.
    CallIdHeader callIdHeader = (CallIdHeader) response.getHeader(CallIdHeader.NAME);
    String callId = callIdHeader.getCallId();
    Subscription subscription = getSubscription(callId);

    // if it's the response to an unsubscribe message, we just ignore it
    // whatever the response is however if we need to handle a
    // challenge, we do it
    ExpiresHeader expHeader = response.getExpires();
    int statusCode = response.getStatusCode();
    SipProvider sourceProvider = (SipProvider) responseEvent.getSource();
    if (((expHeader != null) && (expHeader.getExpires() == 0))
        || (subscription == null)) // this handle the unsubscription
    // case where we removed the contact
    // from subscribedContacts
    {
      boolean processed = false;

      if ((statusCode == Response.UNAUTHORIZED)
          || (statusCode == Response.PROXY_AUTHENTICATION_REQUIRED)) {
        try {
          processAuthenticationChallenge(clientTransaction, response, sourceProvider);
          processed = true;
        } catch (OperationFailedException e) {
          logger.error("can't handle the challenge", e);
        }
      } else if ((statusCode != Response.OK) && (statusCode != Response.ACCEPTED)) processed = true;

      // any other cases (200/202) will imply a NOTIFY, so we will
      // handle the end of a subscription there
      return processed;
    }

    if ((statusCode >= Response.OK) && (statusCode < Response.MULTIPLE_CHOICES)) {
      // OK (200/202)
      if ((statusCode == Response.OK) || (statusCode == Response.ACCEPTED)) {
        if (expHeader == null) {
          // not conform to rfc3265
          logger.error("no Expires header in this response");
          return false;
        }

        SubscriptionRefreshTask refreshTask = new SubscriptionRefreshTask(subscription);
        subscription.setTimerTask(refreshTask);

        int refreshDelay = expHeader.getExpires();
        // try to keep a margin if the refresh delay allows it
        if (refreshDelay >= (2 * refreshMargin)) refreshDelay -= refreshMargin;
        timer.schedule(refreshTask, refreshDelay * 1000);

        // do it to remember the dialog in case of a polling
        // subscription (which means no call to finalizeSubscription)
        subscription.setDialog(clientTransaction.getDialog());

        subscription.processSuccessResponse(responseEvent, statusCode);
      }
    } else if ((statusCode >= Response.MULTIPLE_CHOICES) && (statusCode < Response.BAD_REQUEST)) {
      if (logger.isInfoEnabled())
        logger.info(
            "Response to subscribe to "
                + subscription.getAddress()
                + ": "
                + response.getReasonPhrase());
    } else if (statusCode >= Response.BAD_REQUEST) {
      // if the response is a 423 response, just re-send the request
      // with a valid expires value
      if (statusCode == Response.INTERVAL_TOO_BRIEF) {
        MinExpiresHeader min = (MinExpiresHeader) response.getHeader(MinExpiresHeader.NAME);

        if (min == null) {
          logger.error("no minimal expires value in this 423 " + "response");
          return false;
        }

        ExpiresHeader exp = request.getExpires();

        try {
          exp.setExpires(min.getExpires());
        } catch (InvalidArgumentException e) {
          logger.error("can't set the new expires value", e);
          return false;
        }

        ClientTransaction transac = null;
        try {
          transac = protocolProvider.getDefaultJainSipProvider().getNewClientTransaction(request);
        } catch (TransactionUnavailableException e) {
          logger.error("can't create the client transaction", e);
          return false;
        }

        try {
          transac.sendRequest();
        } catch (SipException e) {
          logger.error("can't send the new request", e);
          return false;
        }

        return true;
        // UNAUTHORIZED (401/407)
      } else if ((statusCode == Response.UNAUTHORIZED)
          || (statusCode == Response.PROXY_AUTHENTICATION_REQUIRED)) {
        try {
          processAuthenticationChallenge(clientTransaction, response, sourceProvider);
        } catch (OperationFailedException e) {
          logger.error("can't handle the challenge", e);

          removeSubscription(callId, subscription);
          subscription.processFailureResponse(responseEvent, statusCode);
        }
        // 408 480 486 600 603 : non definitive reject
        // others: definitive reject (or not implemented)
      } else {
        if (logger.isDebugEnabled()) logger.debug("error received from the network:\n" + response);

        removeSubscription(callId, subscription);
        subscription.processFailureResponse(responseEvent, statusCode);
      }
    }

    return true;
  }
  /**
   * Creates a new SUBSCRIBE request in the form of a <tt>ClientTransaction</tt> with the parameters
   * of a specific <tt>Subscription</tt>.
   *
   * @param subscription the <tt>Subscription</tt> to be described in a SUBSCRIBE request
   * @param expires the subscription duration of the SUBSCRIBE request to be created
   * @return a new <tt>ClientTransaction</tt> initialized with a new SUBSCRIBE request which matches
   *     the parameters of the specified <tt>Subscription</tt>
   * @throws OperationFailedException if the request could not be generated
   */
  private ClientTransaction createSubscription(Subscription subscription, int expires)
      throws OperationFailedException {
    Address toAddress = subscription.getAddress();
    HeaderFactory headerFactory = protocolProvider.getHeaderFactory();

    // Call ID
    CallIdHeader callIdHeader = protocolProvider.getDefaultJainSipProvider().getNewCallId();

    // CSeq
    CSeqHeader cSeqHeader;
    try {
      cSeqHeader = headerFactory.createCSeqHeader(1l, Request.SUBSCRIBE);
    } catch (InvalidArgumentException ex) {
      // Shouldn't happen
      logger.error("An unexpected error occurred while" + "constructing the CSeqHeader", ex);
      throw new OperationFailedException(
          "An unexpected error occurred while" + "constructing the CSeqHeader",
          OperationFailedException.INTERNAL_ERROR,
          ex);
    } catch (ParseException ex) {
      // shouldn't happen
      logger.error("An unexpected error occurred while" + "constructing the CSeqHeader", ex);
      throw new OperationFailedException(
          "An unexpected error occurred while" + "constructing the CSeqHeader",
          OperationFailedException.INTERNAL_ERROR,
          ex);
    }

    // FromHeader and ToHeader
    String localTag = SipMessageFactory.generateLocalTag();
    FromHeader fromHeader;
    ToHeader toHeader;
    try {
      // FromHeader
      fromHeader =
          headerFactory.createFromHeader(protocolProvider.getOurSipAddress(toAddress), localTag);

      // ToHeader
      toHeader = headerFactory.createToHeader(toAddress, null);
    } catch (ParseException ex) {
      // these two should never happen.
      logger.error(
          "An unexpected error occurred while" + "constructing the FromHeader or ToHeader", ex);
      throw new OperationFailedException(
          "An unexpected error occurred while" + "constructing the FromHeader or ToHeader",
          OperationFailedException.INTERNAL_ERROR,
          ex);
    }

    // ViaHeaders
    ArrayList<ViaHeader> viaHeaders = protocolProvider.getLocalViaHeaders(toAddress);

    // MaxForwards
    MaxForwardsHeader maxForwards = protocolProvider.getMaxForwardsHeader();

    Request req;
    try {
      req =
          protocolProvider
              .getMessageFactory()
              .createRequest(
                  toHeader.getAddress().getURI(),
                  Request.SUBSCRIBE,
                  callIdHeader,
                  cSeqHeader,
                  fromHeader,
                  toHeader,
                  viaHeaders,
                  maxForwards);
    } catch (ParseException ex) {
      // shouldn't happen
      logger.error("Failed to create message Request!", ex);
      throw new OperationFailedException(
          "Failed to create message Request!", OperationFailedException.INTERNAL_ERROR, ex);
    }

    populateSubscribeRequest(req, subscription, expires);

    // Transaction
    ClientTransaction subscribeTransaction;
    try {
      subscribeTransaction =
          protocolProvider.getDefaultJainSipProvider().getNewClientTransaction(req);
    } catch (TransactionUnavailableException ex) {
      logger.error(
          "Failed to create subscribe transaction.\n"
              + "This is most probably a network connection error.",
          ex);
      throw new OperationFailedException(
          "Failed to create the subscription transaction",
          OperationFailedException.NETWORK_FAILURE);
    }
    return subscribeTransaction;
  }