(function () {
    
    var switchedArea = null;

    Rakka.switchScreen = function () {
        if (switchedArea == null) {
            switchedArea = $.DIV({});
            
            $("div.sideBar div.outline").hide();

            $("p.redirection").hide();

            $("div.body")
                .children()
                    .hide()
                .end()
                .append(switchedArea);
        }
        else {
            $(switchedArea).empty();
        }
        
        return $(switchedArea);
    };

    Rakka.restoreScreen = function () {
        if (switchedArea == null) {
            throw new Error("Rakka.restoreScreen(): not switched");
        }

        $("div.sideBar div.outline").show();

        $("p.redirection").show();

        $(switchedArea).remove();
        switchedArea = null;

        $("div.body").children().show();
        return null;
    };

    Rakka.getSwitchedScreen = function () {
        return switchedArea;
    };

    var waitingMessageBoard = null;

    Rakka.displayWaitingMessage = function (msg) {
        Rakka.hideWaitingMessage();

        waitingMessageBoard
            = $.P({className: "waitingMessageBoard"},
                  $.P({}, msg));
        
        $("body").append(waitingMessageBoard);
    };

    Rakka.hideWaitingMessage = function () {
        if (waitingMessageBoard != null) {
            $(waitingMessageBoard).remove();
            waitingMessageBoard = null;
        }
    };
    
})();