/**
 * Accessible JavaScript Newsticker
 *
 * Copyright 2006 Wolfgang Bartelme
 * Bartelme Design - http://bartelme.at
 */
 
// 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(){
        this.interval           = 18000;
        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      = "javascript:void(0)";
//        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);

        // Display first message -----------------------------------------------
        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);