(function () {

    var switchedArea = null;

    Rakka.switchScreen = function () {
        if (switchedArea == null) {
            switchedArea = $.DIV({});

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

            $("div.body")
                .children()
                    .hide()
                .end()
                .append(switchedArea);

            $("body").append(
                $.DIV({className: "left sideBarMask"}));

            var btnClose
                = $.INPUT({type     : "button",
                           className: "closeButton",
                           value    : "Close"});
            $("body").append(
                $.DIV({className: "right sideBarMask"},
                      $.DIV({className: "content"},
                            btnClose)));

            $(btnClose).click(function () {
                Rakka.restoreScreen();
            });
        }
        else {
            $(switchedArea).empty();
        }

        return $(switchedArea);
    };

    Rakka.restoreScreen = function () {
        if (switchedArea != null) {
            $("p.redirection").show();

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

            $("div.sideBarMask").remove();

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

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

    Rakka.scrollToTopLeft = function () {
        $("div.center").each(function () {
            this.scrollTop  = 0;
            this.scrollLeft = 0;
        });
    };

    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;
        }
    };

})();