var currentImage = 0;
var numImages = 0;
var moveAmount = 110;
var moveSpeed = 5;

function removeThumbnail(str) {
	var pos = str.indexOf("/tn/");
	return str.substr(0,pos) + str.substr(pos+3)
}

function initImages() {
	var imgObj = document.getElementById("image_thumbnails");
	if (imgObj == null) return;
	var imgImages = imgObj.getElementsByTagName('img');
	numImages = imgImages.length;
	var imgSources = Array();
	for (var i=0; i < numImages; i++) {
		imgSources[i] = removeThumbnail(imgImages[i].src);
	}
	var d=document;
	if (d.images) {
		if (!d.preloadArray) d.preloadArray=new Array();
    	var i,j=d.preloadArray.length,a=imgSources;
    	for (i=0; i<a.length; i++) {
	    	if (a[i].indexOf("#")!=0) {
		    	d.preloadArray[j]=new Image;
	    		d.preloadArray[j++].src=a[i];
	    	}
	    }
    }
    if (numImages <= 3) {
    	greyArrow('right_arrow');
    }
    greyArrow('left_arrow');
}

function greyArrow(str) {
	var imgObj = document.getElementById(str);
	var curSrc = imgObj.src;
	if (curSrc.indexOf("_grey") <= 0) {
		var pos = curSrc.indexOf(".gif");
		imgObj.src = curSrc.substr(0,pos) + '_grey' + curSrc.substr(pos);
	}
}

function activeArrow(str) {
	var imgObj = document.getElementById(str);
	var curSrc = imgObj.src;
	var pos = curSrc.indexOf("_grey");
	if (pos > 0) {
		imgObj.src = curSrc.substr(0,pos) + curSrc.substr(pos+5);
	}
}

function scrollUp() {
	if (currentImage != 0) {
		moveImages(-1);
	}
}

function scrollDown() {
	if (currentImage < numImages-3) {
		moveImages(1);
	}
}

function moveImages(amount) {
	var start = -currentImage * moveAmount;
	currentImage = currentImage + amount;
	var end = -currentImage * moveAmount;
	if (currentImage >= numImages-3) {
		greyArrow('right_arrow');
	}
	else {
		activeArrow('right_arrow');
	}
	if (currentImage <= 0) {
		greyArrow('left_arrow');
	}
	else {
		activeArrow('left_arrow');
	}
	doMove(amount,start,end);
}

function doMove(dir,cur,end) {
	var newPos = cur + (-dir * moveSpeed);
	if ((dir == 1) && (newPos < end)) newPos = end;
	if ((dir == -1) && (newPos > end)) newPos = end;
	var imgObj = document.getElementById("image_thumbnails");
	imgObj.style.left = newPos + "px";
	cur = newPos;
	if (newPos != end) {
		setTimeout("doMove(" + dir  + "," + cur + "," + end + ");",20);
	}
}

function swapImage(num) {
	var imgObj = document.getElementById("image_tn_" + num);
	var newSrc = removeThumbnail(imgObj.src);
	document.getElementById("property_image").src = newSrc;
}