var stop = false;
var current_frame = 1;
var imgs = new Array(4);

function start_slideshow(start_frame, end_frame, delay) {
	setTimeout(switch_slides(start_frame,start_frame,end_frame, delay), 0);
}
						
function switch_slides(frame, start_frame, end_frame, delay) {
	return (function() {
		$(imgs[frame]).hide();
		if (frame == end_frame) { frame = start_frame; } else { frame = frame + 1; }
		current_frame = frame;
		//document.getElementById("nombre-img").innerHTML = imgs[frame];
		setTimeout("$(imgs["+frame+"]).show();", 0);
		if (!stop)
		setTimeout(switch_slides(frame, start_frame, end_frame, delay), delay + 0);
	})
}

function stop_slideshow() {
	stop = true;
}

function restart_slideshow(start_frame, end_frame, delay) {
	stop = false;
	setTimeout(switch_slides(current_frame,start_frame,end_frame, delay), delay);
}



function start_rnd_slideshow(max)
{
	// los tres primeros son fijos y el último, aleatorio
	imgs[0] = 'foto_central-'+ String(generate_rnd(max));
	imgs[1] = 'foto_central-1';
	imgs[2] = 'foto_central-10';
	imgs[3] = 'foto_central-9';
	
	/*for (j = 0; j < 4; j++)
	{
		imgs[j] = 'foto_central-'+ String(generate_rnd(max));
	}*/
	
	start_slideshow(0, 3, 4000);
}

function generate_rnd(max)
{
	i = Math.floor(Math.random() * (max + 1));
	if (i > max)
        i = max;
    if (i <= 0)
        i = 1;
	
	// hack to prevent static images to be choosen
	if (i == 1 || i == 10 || i == 9)
		return generate_rnd(max);
		
    return i;
}