var item_width = 381;
var item_height = 246;
var item_count;
var obj_id = "#moveable-area";
var current_img_pos = 1;
var normal_speed = 400; // milliseconds
var wait_delay = 2000;
var interval_id;

jQuery(document).ready(function(){
	item_count = jQuery(obj_id+" a").length;
	jQuery(obj_id).css("width",item_count*item_width+"px");
	jQuery(obj_id).css("height",item_height+"px");	
	interval_id = setInterval("slide('right', 1)",normal_speed+wait_delay);
});
function slide(direction, step) {	
	if ( step >= item_count ) {
		return false;
	}
	var speed = normal_speed/step;
	if ( direction=="right" && step==1 && current_img_pos==item_count ) {
		direction = "left";
		step = item_count -1;
	}
	var current_left = getNumericValue(jQuery(obj_id).css("left"));
	var move_length = step * item_width;
	if ( direction=="right" ) {		
		jQuery(obj_id).animate({
			'marginLeft' : "-="+ move_length+"px"
		},speed);		
		current_img_pos = current_img_pos + step;
	} else {		
		jQuery(obj_id).animate({
				'marginLeft' : "+="+ move_length+"px"
		},speed);	
		current_img_pos = current_img_pos - step;
	}
	jQuery("#page-area span.page_number").removeClass("selected");
	jQuery("#page-area span#page_number_"+current_img_pos).addClass("selected");
}
function selectPage(page_number) {
	clearInterval(interval_id);
	if ( page_number == current_img_pos ) {
		return false;
	}
	if ( current_img_pos < page_number ) {
		slide("right",page_number-current_img_pos);	
	}
	if ( current_img_pos > page_number ) {
		slide("left",current_img_pos-page_number);	
	}
	interval_id = setInterval("slide('right', 1)",normal_speed+wait_delay);
}
function getNumericValue(str) {
	return parseInt(str.replace("px",""));
}