var preview_per_page = 9;
var current_img = 0;
var src_orange = '/img/px_orange.gif';
var src_white = '/img/px_white.gif';
var src_left = '/img/arrow_left.gif';
var src_right = '/img/arrow_right.gif';

var preview_imgs = new Array();
var preview_links = new Array();
var preview_titles = new Array();
var preview_count = 0;
var preview_start = 0;
var scroll_left;
var scroll_right;

function preview_register(img,title,link) {
	preview_imgs.push(img);
	preview_links.push(link);
	preview_titles.push(title);
	preview_count++;
}

function preview_init(img_id) {
	current_img = img_id;
	block = Math.ceil(img_id / preview_per_page);
	preview_start = (block -1) * preview_per_page;
	if (preview_count < preview_per_page) {
		preview_per_page = preview_count;
	}
	scroll_left = getObjById('scroll_left');
	scroll_right = getObjById('scroll_right');
	update_scrollers();
	update_images();
	preview_highlight();
}

function update_images() {
	for (i = 1; i <= preview_per_page; i ++) {
		link = getObjById('preview_link' + i);
		link.href = preview_links[i - 1 + preview_start];
		img = getObjById('preview_img' + i);
		img.src = preview_imgs[i - 1 + preview_start];
		img.title = preview_titles[i - 1 + preview_start];
	}
}

function update_scrollers() {
	if (scroll_left) {
		if (preview_start != 0) {
			scroll_left.src = src_left;
			scroll_left.onclick = preview_scroll_left;
		} else {
			scroll_left.src = src_white;
			scroll_left.onclick = null;
		}
	}
	if (scroll_right) {
		if (preview_start + preview_per_page < preview_count) {
			scroll_right.src = src_right;
			scroll_right.onclick = preview_scroll_right;
		} else {
			scroll_right.src = src_white;
			scroll_right.onclick = null;
		}
	}
}

function preview_highlight_clear() {
	for (i = 1; i <= preview_per_page; i ++) {
		img_top = getObjById('preview_border_top' + i);
		img_top.src = src_white;
		img_bottom = getObjById('preview_border_bottom' + i);
		img_bottom.src = src_white;
		img_left = getObjById('preview_border_middle' + i);
		img_left.src = src_white;
		img_right = getObjById('preview_border_middle' + (i + 1));
		img_right.src = src_white;
	}
}

function preview_highlight() {
	preview_highlight_clear();
	if ((current_img > preview_start) && (current_img <= preview_start + preview_per_page)) {
		img_top = getObjById('preview_border_top' + (current_img - preview_start));
		img_top.src = src_orange;
		img_bottom = getObjById('preview_border_bottom' + (current_img - preview_start));
		img_bottom.src = src_orange;
		img_left = getObjById('preview_border_middle' + (current_img - preview_start));
		img_left.src = src_orange;
		img_right = getObjById('preview_border_middle' + (current_img - preview_start + 1));
		img_right.src = src_orange;
	}
}

function preview_scroll_left() {
	preview_start -= preview_per_page;
	if (preview_start < 0) {
		preview_start = 0;
	}
	update_scrollers();
	update_images();
	preview_highlight();
}

function preview_scroll_right() {
	preview_start += preview_per_page;
	if (preview_start > preview_count) {
		preview_start = preview_count;
	}
	update_scrollers();
	update_images();
	preview_highlight();
}