Cart = function() {

};

Cart.prototype = {

    setNum: function(input) {

        var itemID = input.parentNode.onkeydown()[0];
        var num    = input.parentNode.onkeydown()[1];
        var price  = input.parentNode.onkeydown()[2];

        var n = parseInt(input.value);
        if (!input.value)
            n = num;
        else
        if (isNaN(n))
            n = input.value = 1;

        this.recountSum(n * price - num * price);
        $('items[' + itemID + '][sum]').innerHTML = n * price;

        input.parentNode.onkeydown = function() {
            return [itemID, n, price];
        }
    },

    recountSum: function(diff) {
        var elm = $('-order-sum');
        var sum = parseInt(elm.innerHTML);
        elm.innerHTML = isNaN(sum) ? diff : (sum + diff);
		elm = $('-order-sum-proc');        
        elm.innerHTML = isNaN(sum) ? diff*0.98 : (sum + diff)*0.98;
    },

    remove: function(URI, button) {
        var num    = button.parentNode.onkeydown()[1];
        var price  = button.parentNode.onkeydown()[2];
		var itemID    = button.parentNode.onkeydown()[0];

        this.recountSum(-1 * num * price);
        button.parentNode.parentNode.removeChild(button.parentNode);
        query(URI+'?item='+itemID, function() {});
    }
}