//http://www.bartelme.at/journal/archive/accessible_javascript_newsticker/
// Create namespace
if (at == undefined) var at = {};
if (at.bartelme == undefined) at.bartelme = {};

// Newsticker Class
at.bartelme.newsticker = Class.create();
at.bartelme.newsticker.prototype = {
    initialize: function() {
        // Get elements
        this.interval = 5000;
        this.container = $("newsticker");
        this.messages = $A(this.container.getElementsByTagName("li"));
        this.number_of_messages = this.messages.length;
        if (this.number_of_messages == 0) {
            //this.showError();
            return false;
        }
        this.current_message = 0;
        this.previous_message = null;
        // Create toggle button
//        this.toggle_button = document.createElement("a");
//        this.toggle_button.href = "#";
//        this.toggle_button.id = "togglenewsticker";
//        this.toggle_button.innerHTML = "Toggle";
//        Event.observe(this.toggle_button, "click", this.toggle.bindAsEventListener(this), false);
//        this.container.appendChild(this.toggle_button);
        this.hideMessages();
        this.showMessage();
        // Install timer
        this.timer = setInterval(this.showMessage.bind(this), this.interval);
    },
    showMessage: function() {
        Effect.Appear(this.messages[this.current_message]);
        setTimeout(this.fadeMessage.bind(this), this.interval - 2000);
        if (this.current_message < this.number_of_messages - 1) {
            this.previous_message = this.current_message;
            this.current_message = this.current_message + 1;
        } else {
            this.current_message = 0;
            this.previous_message = this.number_of_messages - 1;
        }
    },
    fadeMessage: function() {
        Effect.Fade(this.messages[this.previous_message]);
    },
    hideMessages: function() {
        this.messages.each(function(message) {
            Element.hide(message);
        })
    },
    toggle: function() {
        Effect.BlindUp(this.container, 1000);
    },
    showError: function() {
        if (this.container.getElementsByTagName("ul").length == 0) {
            this.list = document.createElement("ul");
            this.container.appendChild(this.list);
        } else {
            this.list = this.container.getElementsByTagName("ul")[0];
        }
        this.errorMessage = document.createElement("li");
        this.errorMessage.className = "error";
        this.errorMessage.innerHTML = "Could not retrieve data";
        this.list.appendChild(this.errorMessage);
    }
}

Event.observe(window, "load", function() { new at.bartelme.newsticker() }, false);