$(function(){
$('.bookshelf').each(function(){

		var BOOK_WIDTH = 140;
		var BOOKZ_WIDTH = 16;
		var BOOK_COUNT = 4;
		var VIEW_WIDTH = BOOK_WIDTH*BOOK_COUNT;
		var BACK_WIDTH = BOOKZ_WIDTH*BOOK_COUNT;
		var contentWidth;
		
		
		var cnt = $(this).find('.bookshelf_content dl').length;
		var arrow_left = $(this).find('.arrow_left');
		var arrow_right = $(this).find('.arrow_right');
		
		
		var book_content = $(this).find('.bookshelf_content');
		book_content.css('width',BOOK_WIDTH*(cnt)+100);
		
		var back_content = $(this).find('.back_content');
		back_content.css({width:BOOKZ_WIDTH*(cnt)+10});
		
		
	
		
		
		var current = 0;
		var total=Math.floor((cnt-1)/4);
		
		if(cnt<=4) arrow_left.hide();
		arrow_right.hide();
		
		
		
		var checkArrow = function(){
			arrow_left.show();
			arrow_right.show();
			
			if(current == 0 ){
				arrow_right.hide();
			}
			if(current >= total){
				arrow_left.hide();
			}
		}
		arrow_left.click(function(){
				current++;
				book_content.animate({
					'left':-current*VIEW_WIDTH + 'px'
				},'normal','easeOutQuad');
				
				var ad = current == total ? -20 : 0;
				back_content.animate({
					'left':-current*BACK_WIDTH + ad + 'px'
					},550,'easeOutQuad');
					
				checkArrow();
		});
		arrow_right.click(function(){
				current = Math.max(0,--current);
				book_content.animate({
					'left':-current*VIEW_WIDTH + 'px'
					},'normal','easeOutQuad');	
					
				back_content.animate({
					'left':-current*BACK_WIDTH + 'px'
					},550,'easeOutQuad');
					
					
				checkArrow();
		});
		
	
	})
})