eBay Tracking Code for WooCommerce 2.x

<?php
    /**
     * eBay Pixel Tracking Code for WooCommerce
     * @author : eBay / PeppermintJamNetwork
     * @author : Imperative Ideas (@imperativeideas)
     * @description : A modified version of the eBay Tracking Code for use with WooCommerce 2.x
     */

    // Enter your product ID below (IMPORTANT)
    $pid = "";

    /** DO NOT EDIT BELOW THIS LINE UNLESS YOU KNOW WHAT YOU ARE DOING **/

    $order_id = $_GET['order'];
    $order = new WC_Order($order_id);
    $items = $order->get_items();

    //order discount total
    $discount = $order->get_order_discount();

        //Begin the output, replace iframe with <pre> in order to see result w/o sending
        $output = '<iframe src="https://t.pepperjamnetwork.com/track?';
        $output .= "PID=$pid"; // gets the product ID variable
        $output .= "&INT=ITEMIZED"; // This is so eBay understands the formatting

        $i = 1; //Start the counter and iterate per product in the loop
        foreach( $items as $item ) {
            if ( $item['product_id'] > 0 ) {    // We should replace this with !empty()
                $quantity = $item['qty'];       // Get data from the order
                $price = $item['line_total'];       // Get data from the order

                    if ( !empty($item['variation_id']) ) {      // Check for a product variation
                            $id = $item['variation_id'];        // Assign variation ID
                    } else {
                    $id = $item['product_id'];      // Else use base ID
                    }

                    // Get the SKU based on the product ID (order does not tell us this information)
                    $productmeta = new WC_Product($id);
                    $sku = $productmeta->post->sku;

            //add_qty($quantity);
            $output .= '&ITEM' . $i . '=' . $sku;   // write SKU to output
            $output .='&QTY'.$i.'='. $quantity; // write quantity to output

            if ($i == 1 && $discount) {     // Check for a coupon & calculate
                $returnprice = $price - $discount;
                $output .='&TOTALAMOUNT'.$i.'='. $returnprice;
            } else {
                $output .='&TOTALAMOUNT'.$i.'='. $price;
            }

            $i++; //increase the counter
            }
        }

        $output .='&OID='.$order_id;                    // Output order ID
    $output .='" width="1" height="1" frameborder="0"></iframe>';   // Close iframe (or <pre> if echoing)
    echo $output;                           // Echo result
    ?>