var current_item = 0;
var items_count = 3;
var fading_speed = 800;
var fading_period = 8000;
var cancel_next = false;

$(document).ready(function(){
	setTimeout(function(){roll(-1);}, fading_period);
})

function roll(index){
	var next_item;
	
	if( index == current_item ){
		cancal_next = false;
		return;
	}
	
	
	
	if( index == -1 ){
		setTimeout(function(){roll(-1);}, fading_period);
		
		if (cancel_next == true){
			cancal_next = false;
			return;
		}
		
		next_item = current_item + 1;
		if( next_item == items_count ) next_item = 0;
	}else{
		next_item = index;
		cancel_next = true;
	}
	
	$('#item_' + current_item).fadeOut(fading_speed);
	$('#item_' + current_item + "_button").removeClass("active_button");
	$('#item_' + current_item + "_button").addClass("inactive_button");
	
	current_item = next_item;
	
	$('#item_' + current_item).fadeIn(fading_speed);
	$('#item_' + current_item + "_button").addClass("active_button");
	$('#item_' + current_item + "_button").removeClass("inactive_button");
}