/**
   * This is the main method of this class. For every message user sends it checks if it is
   * "!addlister" and if it then it clears the message from skype and adds one {@link
   * GroupChatListener listener} for this specific chat.
   *
   * <p>Also this method checks if user has activated edit lister. If he has then it also registers
   * and one {@link GroupChatEditListener editListener} for the specific chat.
   *
   * @see com.skype.ChatMessageListener#chatMessageSent(com.skype.ChatMessage)
   */
  @Override
  public void chatMessageSent(ChatMessage sent) throws SkypeException {
    if (!sent.getContent().equalsIgnoreCase("!addlistener")) return;

    Chat chat = sent.getChat();
    if (!registeredChats.contains(chat)) {
      sent.setContent("");

      GroupChatListener group = new GroupChatListener(chat);
      Skype.addChatMessageListener(group);

      // System.out.println(chat.getWindowTitle());

      if (Config.EnableEdits) Skype.addChatMessageEditListener(group.getEditListener());

      registeredChats.add(chat);
    }
  }