var MerryGoRound=new Class({Implements:[Events,Options],options:{selector:'*',cycle:false,per_page:'auto',page_controls:false,fx_options:{'property':'margin-left','link':'cancel'},wrapper_tag:'div',wrapper_options:{'class':'merry-go-round-wrapper','styles':{'position':'relative'}},button_event:'click',previous_button_tag:'a',previous_button_options:{'html':'«','class':'merry-go-round-previous','styles':{'position':'absolute','left':0}},next_button_tag:'a',next_button_options:{'html':'»','class':'merry-go-round-next','styles':{'position':'absolute','right':0}},current_page_class:'merry-go-round-current-page',page_controls_tag:'div',page_controls_options:{'class':'merry-go-round-pagination','styles':{'overflow':'auto'}}},initialize:function(elem,options){this.setOptions(options);this.inner_element=$(elem);var method=this.inner_element.getParent()?'wraps':'grab';this.element=new Element(this.options.wrapper_tag,this.options.wrapper_options)[method](this.inner_element);this.riders=this.element.getFirst().getChildren(this.options.selector);this.current_index=0;if(this.riders.length===0)return;this.scroll=new Fx.Tween(this.inner_element,this.options.fx_options);this.setup_styles();this.setup_pages();if(this.pages.length>1){if(this.options.page_controls)this.setup_page_controls();this.inject_buttons();this.add_events();this.fireEvent('pageShown',[0,this]);}
return this;},setup_styles:function(){this.element.setStyles({'height':this.options.wrapper_height||this.riders[0].getHeight(),'width':this.options.wrapper_width||this.inner_element.getWidth()});var total_height=0;this.riders.each(function(x){total_height+=x.getWidth()+x.getStyle('margin-left').toInt()+x.getStyle('margin-right').toInt();});this.inner_element.setStyles({'width':total_height,'overflow':'hidden'});},setup_pages:function(){this.pages=[];if(this.options.per_page=='auto'){var right_edge=this.element.getWidth();this.pages.include(this.riders[0]);for(var i=1,ii=this.riders.length;i<ii;i++){var rider_left=this.riders[i].getPosition(this.inner_element).x;var rider_width=this.riders[i].getWidth()+this.riders[i].getStyle('margin-left').toInt()+this.riders[i].getStyle('margin-right').toInt();if((rider_left<right_edge&&rider_left+rider_width>right_edge)||(i>0&&rider_left>=right_edge&&!this.riders[i-1].retrieve('merry-go-round-page'))){this.riders[i].store('merry-go-round-page',true);this.pages.include(this.riders[i]);right_edge=-this._calculate_scroll(this.riders[i])+this.element.getWidth();}}}else if(this.options.per_page===1){this.pages=this.riders;}else{for(var i=1,ii=this.riders.length;i<ii;i++){if(i%this.options.per_page===0)this.pages.include(this.riders[i]);}}},setup_page_controls:function(){this.page_controls=new Element(this.options.page_controls_tag,this.options.page_controls_options).adopt(this.pages.map(function(p,i){var tag=this.options.page_controls_tag.test('ul','i')?'li':this.options.page_controls_tag;return new Element(tag,{'class':i===0?this.options.current_page_class:'','events':{'click':this.scroll_to_page.bind(this,i)}});},this)).inject(this.element);var total_width=0;this.page_controls.getChildren().each(function(x){total_width+=x.getWidth()+x.getStyle('margin-left').toInt()+x.getStyle('margin-right').toInt();});this.page_controls.setStyle('width',total_width);},inject_buttons:function(){var buttons=[this.previous_button=new Element(this.options.previous_button_tag,this.options.previous_button_options),this.next_button=new Element(this.options.next_button_tag,this.options.next_button_options)];this.element.adopt(buttons);buttons.each(function(button){button.setStyle('top',button.getParent().getHeight()/2-button.getHeight()/2);});if(!this.options.cycle)this.previous_button.setStyle('display','none');},add_events:function(){this.previous_button.addEvent(this.options.button_event,this.previous.bind(this));this.next_button.addEvent(this.options.button_event,this.next.bind(this));},next:function(){this.scroll_to_page(++this.current_index);},previous:function(){this.scroll_to_page(--this.current_index);},_hide_or_show_buttons:function(page_index){if(!this.options.cycle){if(page_index===0)
this.previous_button.setStyle('display','none');else
this.previous_button.setStyle('display','block');if(page_index+1===this.pages.length)
this.next_button.setStyle('display','none');else
this.next_button.setStyle('display','block');}},_update_page_controls:function(page_index){$(this.page_controls).getChildren()
.removeClass(this.options.current_page_class)
[page_index].addClass(this.options.current_page_class);},_calculate_scroll:function(elem){return-elem.getPosition(this.inner_element).x+elem.getStyle('margin-left').toInt()+this.inner_element.getStyle('padding-left').toInt();},scroll_to_page:function(page_index){if(page_index<0)page_index=this.pages.length+page_index;else page_index=page_index%this.pages.length;this.current_index=page_index;this.fireEvent('pageShown',[page_index,this]);this._hide_or_show_buttons(page_index);if(this.options.page_controls)this._update_page_controls(page_index);this.scroll.start(this._calculate_scroll(this.pages[page_index]));}});