var SLIDETIMER = 3;
var SLIDESPEED = 3;
var SCROLLTIMER = 3;
var SCROLLSPEED = 3;
var STARTINGOPACITY = 40;

// handles section to section scrolling of the content //
function slideContent(id,prefix,timer) {
	var div = document.getElementById(id);
	var slider = div.parentNode;
	clearInterval(slider.timer);
	slider.section = parseInt(id.replace(/\D/g,''));
	slider.target = div.offsetTop;
	slider.style.top = slider.style.top || '0px';
	slider.current = slider.style.top.replace('px','');
	slider.direction = (Math.abs(slider.current) > slider.target) ? 1 : -1;
	slider.style.opacity = STARTINGOPACITY * .01;
	slider.style.filter = 'alpha(opacity=' + STARTINGOPACITY + ')';
	slider.timer = setInterval( function() { slideAnimate(slider,prefix,timer) }, SLIDETIMER);
}

function slideAnimate(slider,prefix,timer) {
	var curr = Math.abs(slider.current);
	var tar = Math.abs(slider.target);
	var dir = slider.direction;
	if((tar - curr <= SLIDESPEED && dir == -1) || (curr - tar <= SLIDESPEED && dir == 1)) {
		slider.style.top = (slider.target * -1) + 'px';
		slider.style.opacity = 1;
		slider.style.filter = 'alpha(opacity=100)';
		clearInterval(slider.timer);
		if(slider.autoscroll) {
			setTimeout( function() { autoScroll(slider.id,prefix,timer) }, timer * 1000);
		}
	} else {
		var pos = (dir == 1) ? parseInt(slider.current) + SLIDESPEED : slider.current - SLIDESPEED;
		slider.current = pos;
		slider.style.top = pos + 'px';
	}
}

// handles manual scrolling of the content //
function scrollContent(id,dir) {
	var div = document.getElementById(id);
	clearInterval(div.timer);
	var sections = div.getElementsByTagName('div');
	var length = sections.length;
	var limit;
	if(dir == -1) {
		limit = 0;
	} else {
		if(length > 1) {
			limit = sections[length-1].offsetTop + sections[length-1].offsetHeight - div.parentNode.offsetHeight + 3;
			//alert(limit);
		} else {
			limit = sections[length-1].offsetHeight - div.parentNode.offsetHeight + 20;
		}
	}
	div.style.opacity = STARTINGOPACITY * .01;
	div.style.filter = 'alpha(opacity=' + STARTINGOPACITY + ')';
	div.timer = setInterval( function() { scrollAnimate(div,dir,limit) }, SCROLLTIMER);
}

function scrollAnimate(div,dir,limit) {
	div.style.top = div.style.top || '0px';
	var top = div.style.top.replace('px','');
	if(dir == 1) {
		if(limit - Math.abs(top) <= SCROLLSPEED) {
			cancelScroll(div.id);
			div.style.top = '-' + limit + 'px';
		} else {
			div.style.top = top - SCROLLSPEED + 'px';
		}
	} else {
		if(Math.abs(top) - limit <= SCROLLSPEED) {
			cancelScroll(div.id);
			div.style.top = limit + 'px';
		} else {
			div.style.top = parseInt(top) + SCROLLSPEED + 'px';
		}
	}
}

// cancel the scrolling on mouseout //
function cancelScroll(id) {
	var div = document.getElementById(id);
	div.style.opacity = 1;
	div.style.filter = 'alpha(opacity=100)';
	clearTimeout(div.timer);
}

// initiate auto scrolling //
function autoScroll(id,prefix,timer,restart) {
	var div = document.getElementById(id);
	div.autoscroll = (!div.autoscroll && !restart) ? false : true;
	if(div.autoscroll) {
		var sections = div.getElementsByTagName('div');
		var length = sections.length;
		div.section = (div.section && div.section < length) ? div.section + 1 : 1;
		slideContent(prefix + '-' + div.section,prefix,timer);
	}
}

// cancel automatic scrolling //
function cancelAutoScroll(id) {
	var div = document.getElementById(id);
	div.autoscroll = false;
}