function ProductSell(o){
	
	/**reference for the instance*/
	var app = this;
	/**currently loaded product*/
	var product = null;
	
	this.defaults = {
		/**id of filter text*/
		selector_filter_text: '#filter_text',
		/** ajax url for lookup service*/
		lookup_product_url: '',
		/**the id of form*/
	    selector_form: '#product_form',
	    /**form contains error text*/
	    form_invalid: 'Az ürlap hibákat tartalmaz',
	    /**list of sold items by current user*/
	    sold_items: [],
	};
	
	init();
	
	function init(){
		$.extend(app.defaults, o );
		addBehaviorEnterPressedListener();
		addBehaviourBtnSell();
		addBehaviourBtnSellAndAppendToBill();
		addBehaviorAjaxSubmit();
		setFocus();
		addBehaviorCountEnterPressedListener();
		addBehaviorCountChangedListener();
		addBehaviorCurrencyEnterPressedListener();
		addBehaviorAccountEnterPressedListener();
		addBehaviorDiscountEnterPressedListener();
		productChanged();
		createUserSoldItemsTable();
	}
	
	/**
	 * set the focus for text input #filter_text
	 * */
	function setFocus(){
		$("#filter_text").focus();
		
	}
	
	/**listen for enter key pressed on #filter_text*/
	function addBehaviorEnterPressedListener(){
		$(   app.defaults.selector_filter_text ).keypress(function( event ) {
			  if ( event.which == 13 ) {
				  event.preventDefault();
				  lookupProduct();
			  }
		});	
	}
	
	/**listen for enter key pressed on #productsaleform-count*/
	function addBehaviorCountEnterPressedListener(){
		$(   '#productsaleform-count' ).keypress(function( event ) {
			if ( event.which == 13 ) {
				event.preventDefault();
				event.stopImmediatePropagation();
				$('#productsaleform-id_currency').focus();
			}
		});	
	}
	/**listen for enter key pressed on #productsaleform-id_currency*/
	function addBehaviorCurrencyEnterPressedListener(){
		$(   '#productsaleform-id_currency' ).keypress(function( event ) {
			if ( event.which == 13 ) {
				event.preventDefault();
				event.stopImmediatePropagation();
				$('#productsaleform-id_account').focus();
			}
		});	
	}
	/**listen for enter key pressed on #productsaleform-id_account*/
	function addBehaviorAccountEnterPressedListener(){
		$(   '#productsaleform-id_account' ).keypress(function( event ) {
			if ( event.which == 13 ) {
				event.preventDefault();
				event.stopImmediatePropagation();
				$('#productsaleform-id_discount').focus();
			}
		});	
	}
	/**listen for enter key pressed on #productsaleform-id_discount*/
	function addBehaviorDiscountEnterPressedListener(){
		$(   '#productsaleform-id_discount' ).keypress(function( event ) {
			if ( event.which == 13 ) {
				event.preventDefault();
				event.stopImmediatePropagation();
				$('#productsaleform-comment').focus();
			}
		});	
	}
	/**listen for event "change"  #productsaleform-count*/
	function addBehaviorCountChangedListener(){
		$(   '#productsaleform-count' ).change(function( event ) {
			refreshCalculatedValues();
			 
		});	
	}
	
	/**load a product from server by exact barcode or product number*/
	function lookupProduct(){
		var data, url;
		
		url = app.defaults.lookup_product_url;
		data = {
			'query' : 	$(  app.defaults.selector_filter_text ).val()
		};
		
		$.ajax({
			  dataType: "json",
			  url: url,
			  data: data,
			  success: onLookupProductReady
			});
	}
	
	/**succes event handler after lookup product event*/
	function onLookupProductReady(  data  ){
		app.product = data.product;
		productChanged();
	}
	
	/**handles product change.*/
	function productChanged( ){
		clearForm();
		if ( app.product != null){
			applyProduct( app.product);
			refreshCalculatedValues();
			$("#productsaleform-count").focus().select();
		}
	}
	
	function clearForm(){
		var table;
		table = $('.table-product');
		table.find('.product-name').html('-');
		table.find('.product-price').html('-');
		table.find('.product-number').html('-');
		table.find('.product-barcode').html('-');
		table.find('.product-stock').html('-');
		table.find('.product-price').html('-');
		table.find('.product-sale-price').html('-');
		table.find("#productsaleform-count").val(1);
		table.find('#productsaleform-id_product').val('');
		table.find('#productsaleform-id_account').val('');
	}
	
	function applyProduct(product){
		var table;
		table = $('.table-product');
		table.find('#productsaleform-id_product').val(product.id_product);
		table.find('.product-name').html(product.name);
		table.find('.product-sale-price').html(product.sale_price);
		table.find('.product-number').html(product.product_number);
		table.find('.product-barcode').html(product.barcode);
		table.find('.product-stock').html(product.stock);
		table.find('#productsaleform-id_account').val(product.id_account);
		
	}
		
	function refreshCalculatedValues(){
		var count,price;
		count = $("#productsaleform-count").val();
		count = +count;
		if ( isNaN(count)){
			count = 0;
		}
		price = count * app.product.sale_price;
		$('.product-count').html(count);
		$('.product-price').html(price);
	}

	function addBehaviourBtnSell(){
		$('#btn_sell').on('click',submitSell);
	}
	
	function addBehaviourBtnSellAndAppendToBill(){
		$('#btn_sell_append').on('click',submitSellAndAppend);
	}
	
	function submitSell(){
		$('#productsaleform-append_to_sold_list').val('');
		$('#product_form').submit();
	}
	function submitSellAndAppend(){
		$('#productsaleform-append_to_sold_list').val('append');
		$('#product_form').submit();
	}
	
	
	function refreshSoldUseritems(){
		$('.sold-items-container').transferList('option','transfers' , app.defaults.sold_items );
	}
	
	function addBehaviorAjaxSubmit(){
		
		$('body').on('beforeSubmit', '#product_form', function () {
			     var form = $(this);
			     // return false if form still have some validation errors
			     if (form.find('.has-error').length) {
			    	 $.notify(app.defaults.form_invalid, { 'type' : 'success' });
			          return false;
			     }
			     // submit form
			     $.ajax({
			          url: form.attr('action'),
			          type: 'post',
			          data: form.serialize(),
			          success: function (response) {
			               // do something with response
			        	  if ( response.code == 'success'){
			        		  $.notify(response.message, { 'type' : 'success' });
			        		  clearForm();
			        		  refreshCalculatedValues();
			        		  $("#filter_text").val('');
			        		  setFocus();
			        		  app.defaults.sold_items = response.transfers; 
			        		  $('.sold-items-container').transferList( 'option', 'transfers' , app.defaults.sold_items );
			        		  
			        	  }else if ( response.code == 'invalid'){
			        		  if ( response.errors ){
			        			  	$.each(response.errors, function (key, value){
			        			  		var message;
			        			  		message = $.map(value, function(obj){ return obj }).join('  ');
				        			  		$.notify(message, { 'type' : 'danger' });
				        			  	}
			        			  	);
			        		  }
			        	  }
			          }
			     });
			     return false;
			});
		
	}
	
	
	function createUserSoldItemsTable(){
		console.info(  app.defaults.sold_items );
		$('.sold-items-container').transferList({
			'transfers' : app.defaults.sold_items
		});
	}
	
	
	
}