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;
        } 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 = newsNo;
            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;
}