     validateKey   : "01001101 ... I am checking this session key, $0."
     joinSession   : "01001010 ... Joining session, $0"
     noSession     : "Sorry, looks like this session is closed by its host, I cannot get you in."
+    invalidKey    : "Sorry, looks like this session key is not valid anymore."
     help          : """
         If you type,
         "invite username" I can bring someone to your session,

      @botReply getMessage "validateKey", sessionKey
      @workspace.firebaseRef.child(sessionKey).once "value", (snapshot) =>
        if snapshot.val() is null or not snapshot.val().keys
          @botReply message.noSession
        else
          @botReply getMessage "joinSession", sessionKey
          @workspace.getDelegate().emit "JoinSessionRequested", sessionKey
    else
      # TODO: fatihacet - implement getting the sessionKey via username

  replyForInvite: (usernames) ->
    # TODO: fatihacet - currently invite only first user


    return originUser is KD.nick() and isSystemMessage

  isSystemMessage: (message) ->
    return  unless message
    splitted = message.split " "
    return splitted.length is 2 and replyHandlers[splitted.first] isnt undefined

  runSystemMessageHandler: (message) ->
    splitted = message.split " "
