/**
   * Sends a file transfer request to the given <tt>toContact</tt> by specifying the local and
   * remote file path and the <tt>fromContact</tt>, sending the file.
   *
   * @param toContact the contact that should receive the file
   * @param file the file to send
   * @return the transfer object
   * @throws IllegalStateException if the protocol provider is not registered or connected
   * @throws IllegalArgumentException if some of the arguments doesn't fit the protocol requirements
   */
  public FileTransfer sendFile(Contact toContact, File file)
      throws IllegalStateException, IllegalArgumentException {
    assertConnected();

    if (file.length() > getMaximumFileLength())
      throw new IllegalArgumentException("File length exceeds the allowed one for this protocol");

    // Get the aim connection
    AimConnection aimConnection = icqProvider.getAimConnection();

    // Create an outgoing file transfer instance
    OutgoingFileTransfer outgoingFileTransfer =
        aimConnection
            .getIcbmService()
            .getRvConnectionManager()
            .createOutgoingFileTransfer(new Screenname(toContact.getAddress()));

    String id =
        String.valueOf(outgoingFileTransfer.getRvSessionInfo().getRvSession().getRvSessionId());

    FileTransferImpl outFileTransfer =
        new FileTransferImpl(outgoingFileTransfer, id, toContact, file, FileTransfer.OUT);

    // Adding the file to the outgoing file transfer
    try {
      outgoingFileTransfer.setSingleFile(new File(file.getPath()));
    } catch (IOException e) {
      if (logger.isDebugEnabled()) logger.debug("Error sending file", e);
      return null;
    }

    // Notify all interested listeners that a file transfer has been
    // created.
    FileTransferCreatedEvent event = new FileTransferCreatedEvent(outFileTransfer, new Date());

    fireFileTransferCreated(event);

    // Sending the file
    outgoingFileTransfer.sendRequest(new InvitationMessage(""));

    outFileTransfer.fireStatusChangeEvent(FileTransferStatusChangeEvent.PREPARING);

    return outFileTransfer;
  }
  /**
   * Sends a file transfer request to the given <tt>toContact</tt>.
   *
   * @return the transfer object
   * @param toContact the contact that should receive the file
   * @param file file to send
   * @param gw special gateway to be used for receiver if its jid misses the domain part
   */
  FileTransfer sendFile(Contact toContact, File file, String gw)
      throws IllegalStateException, IllegalArgumentException, OperationNotSupportedException {
    OutgoingFileTransferJabberImpl outgoingTransfer = null;

    try {
      assertConnected();

      if (file.length() > getMaximumFileLength())
        throw new IllegalArgumentException("File length exceeds the allowed one for this protocol");

      String fullJid = null;
      // Find the jid of the contact which support file transfer
      // and is with highest priority if more than one found
      // if we have equals priorities
      // choose the one that is more available
      OperationSetMultiUserChat mucOpSet =
          jabberProvider.getOperationSet(OperationSetMultiUserChat.class);
      if (mucOpSet != null && mucOpSet.isPrivateMessagingContact(toContact.getAddress())) {
        fullJid = toContact.getAddress();
      } else {
        Iterator<Presence> iter =
            jabberProvider.getConnection().getRoster().getPresences(toContact.getAddress());
        int bestPriority = -1;

        PresenceStatus jabberStatus = null;

        while (iter.hasNext()) {
          Presence presence = iter.next();

          if (jabberProvider.isFeatureListSupported(
              presence.getFrom(),
              new String[] {
                "http://jabber.org/protocol/si",
                "http://jabber.org/protocol/si/profile/file-transfer"
              })) {

            int priority =
                (presence.getPriority() == Integer.MIN_VALUE) ? 0 : presence.getPriority();

            if (priority > bestPriority) {
              bestPriority = priority;
              fullJid = presence.getFrom();
              jabberStatus =
                  OperationSetPersistentPresenceJabberImpl.jabberStatusToPresenceStatus(
                      presence, jabberProvider);
            } else if (priority == bestPriority && jabberStatus != null) {
              PresenceStatus tempStatus =
                  OperationSetPersistentPresenceJabberImpl.jabberStatusToPresenceStatus(
                      presence, jabberProvider);
              if (tempStatus.compareTo(jabberStatus) > 0) {
                fullJid = presence.getFrom();
                jabberStatus = tempStatus;
              }
            }
          }
        }
      }

      // First we check if file transfer is at all supported for this
      // contact.
      if (fullJid == null) {
        throw new OperationNotSupportedException(
            "Contact client or server does not support file transfers.");
      }

      if (gw != null && !fullJid.contains("@") && !fullJid.endsWith(gw)) {
        fullJid = fullJid + "@" + gw;
      }

      OutgoingFileTransfer transfer = manager.createOutgoingFileTransfer(fullJid);

      outgoingTransfer =
          new OutgoingFileTransferJabberImpl(toContact, file, transfer, jabberProvider);

      // Notify all interested listeners that a file transfer has been
      // created.
      FileTransferCreatedEvent event = new FileTransferCreatedEvent(outgoingTransfer, new Date());

      fireFileTransferCreated(event);

      // Send the file through the Jabber file transfer.
      transfer.sendFile(file, "Sending file");

      // Start the status and progress thread.
      new FileTransferProgressThread(transfer, outgoingTransfer).start();
    } catch (XMPPException e) {
      logger.error("Failed to send file.", e);
    }

    return outgoingTransfer;
  }