var bSS = false;
var iScrollTimeout = 1;
var iTimeOut = window.addEventListener ? iScrollTimeout * 2 : iScrollTimeout;
var iScrollKoef = 8;
var iCW, iTW, iTL, iTR, iDiff;
var oContainer = null;
var oThumbs = null;
var oLeftArr = null;
var oRightArr = null;


function initScrollVars(){
	iCW = oContainer.offsetWidth;
	iTW = oThumbs.offsetWidth;
	iTL = oThumbs.offsetLeft;
	iDiff = iTW - iCW;
	iTR = -(iTL + iDiff);
}

function scrollInit(){
	if(oContainer = document.getElementById('gn_container')){
	if(oThumbs = document.getElementById('gn_thumbs')){
	if(oLeftArr = document.getElementById('gn_arr_left')){
	if(oRightArr = document.getElementById('gn_arr_right')){
		if(oContainer.attachEvent){
			oContainer.attachEvent("onmousewheel", mouseScrollThumbs);
		} else {
			oContainer.addEventListener("DOMMouseScroll", mouseScrollThumbs, true);
		}
		if(window.addEventListener){
			window.addEventListener('resize', resizeThumbs, false);
		} else {
			window.attachEvent('onresize', resizeThumbs);
		}
		checkScrollButtons();
		//checkSelectedPosition();
		resizeThumbs();
	}
	}
	}
	}
}

function checkSelectedPosition(){
	if(oThumbs){
		var i = 0;
		var num = 0;
		oSelThumb = null;
		for (i = 0; i < a.length; i++) {
			if(oThumb = document.getElementById('th' + a[i])) {
				if(oThumb.className == 'sel'){
					oSelThumb = oThumb;
					num = i;
				}
			}
		}
		iLeft = Math.round(iCW / 2 - (iTW / a.length) * (num + 1/2));
		iLeft = iLeft + iTW < iCW ? iCW - iTW : iLeft;
		iLeft = iLeft > 0 ? 0 : iLeft;
		oThumbs.style.left = iLeft + 'px';
	}
}

function checkScrollButtons(){
	initScrollVars();
	if(iDiff > 0){
		bRA = iTR < 0 ? true : false;
		bLA = iTL < 0 ? true : false;
	} else {
		bLA = false; bRA = false;
	}

	oLeftArr.style.visibility = bLA ? '' : 'hidden';
	oRightArr.style.visibility = bRA ? '' : 'hidden';
}

function resizeThumbs(){
	if(oThumbs){
		initScrollVars();
		if(iTL < 0){
			if(iDiff < 0) {
				oThumbs.style.left = '0px';
			} else if(iDiff > 0) {
				if(iTR >= 0){
					oThumbs.style.left = -iDiff + 'px';
				}
			}
		} else {
			oThumbs.style.left = '0px';
		}
		checkScrollButtons();
	}
}

function scrollThumbs(sSS, sDirection){
	bSS = sSS == 'start' ? true : false;
	iDirection = sDirection == 'left' ? -1 : 1;
	_scroll(iDirection);
}

function mouseScrollThumbs(evt){
	if(!evt) evt = window.event;
	if(evt.wheelDelta) {
		delta = evt.wheelDelta / 120;
		if(window.opera) delta = -delta;
	} else if (evt.detail) {
		delta = -evt.detail / 3;
	}
	iDirection = delta > 0 ? -1 : 1;
	_scroll(iDirection, delta * 5);
	if (evt.preventDefault) evt.preventDefault();
	evt.returnValue = false;
	return false;
}

function _scroll(iDirection, iKoef){
	var iMultiplier = !isNaN(iKoef) ? Math.abs(iKoef) : 1;
	var iShift = iScrollKoef * iMultiplier * iDirection;

	initScrollVars();
	if(oThumbs && iCW > 0){
		if(iDiff > 0) {
			if(iTL > iShift) {
				oThumbs.style.left = '0px';
			} else { 
				if((iDiff + iTL) < iShift) {
					oThumbs.style.left = -iDiff + 'px';	
				} else {
					oThumbs.style.left = (iTL - iShift) + 'px';
					if(bSS){
						setTimeout('_scroll(' + iDirection + ')', iTimeOut);
					}
				}
			}
		}
	}
	checkScrollButtons();
}