var SlideShow = Class.create(
{
	index: null,
	pe: null,

	initialize: function(images, interval, duration, callback)
	{
		this.images	= images;
		this.length	= this.images.size();
		this.interval	= interval;
		this.duration	= duration;
		this.callback	= callback;

		this.length > 0 && this.init();
	},

	init: function(index)
	{
		this.index = null;

		this.images.each(function(element) { element.hide(); element.setOpacity(0); });

		this.show(index);

		this.length > 1 && this.start();
	},

	show: function(index)
	{
		var morph = this.index !== null;

                this.index = (index == undefined ? (morph ? ++this.index%this.length : 0) : index);

		this.images[this.index].show();

		morph && new Effect.Opacity(this.images[(this.length + this.index - 1)%this.length], { from: 1.0, to: 0.0, duration: this.duration, afterFinish: function(effect) { effect.element.hide(); } });
		new Effect.Opacity(this.images[this.index], { from: 0.0, to: 1.0, duration: morph ? this.duration : 0 });

		this.callback && this.callback(this.index);
	},

	start: function()
	{
		this.pe = new PeriodicalExecuter(function() { this.show(); }.bind(this), this.interval);
	},

	stop: function()
	{
		this.pe && this.pe.stop();
	},

	goto: function(index)
	{
		this.pe && this.pe.stop();

		this.init(index);
	}
});