WooCommerce - Transpose Cart loop in Order loop for pdf invoices

Question

I'm using woocommerce and "Print Invoices & Packing lists" available at "https://woocommerce.com/products/print-invoices-packing-lists/" . For Display the Total Saving in the woocommerce cart & checkout pages I'm used this code and works perfectly :

 function bbloomer_wc_discount_total() {

    global $woocommerce;

    $cart_subtotal = $woocommerce->cart->cart_contents;

    $discount_total = 0;

  foreach ($woocommerce->cart->cart_contents as $product_data) {

        if ($product_data['variation_id'] > 0) {
            $product = wc_get_product( $product_data['variation_id'] );
        } else {
            $product = wc_get_product( $product_data['product_id'] );
        }

        if ( !empty($product->sale_price) ) {
        $discount = ($product->regular_price - $product->sale_price) * $product_data['quantity'];
        $discount_total += $discount;
        }

    }

    if ( $discount_total > 0 ) {
    echo '<tr class="cart-discount">
    <th>'. __( 'Total Saving :', 'woocommerce' ) .'</th>
    <td data-title=" '. __( 'Total Saving :', 'woocommerce' ) .' ">'
    . wc_price($discount_total+$woocommerce->cart->discount_cart) .'</td>
    </tr>';
    }
}

add_action( 'woocommerce_cart_totals_after_order_total', 'bbloomer_wc_discount_total');
add_action( 'woocommerce_review_order_after_order_total', 'bbloomer_wc_discount_total');

This function based in the woocommerce cart contents . How I can Display The Total Saving in the Html Invoice generated By Print Invoices & Packing lists Plugin ( based On the Order Instead of the cart contents ) in the plugin Hooks like :

add_action( 'wc_pip_after_header', 'bbloomer_wc_discount_total'); add_action( 'wc_pip_document_header', 'bbloomer_wc_discount_total');

Answer 1

— Update 2 — (Added compatibility for WooCommerce version 3+)

Now as I know you are using WooCommerce PDF Invoices & Packing Slips plugin.

This code can only be used directly in invoice.php PIP template at the beginning, replacing <?php global $wpo_wcpdf ?> by this:

<?php 

    global $wpo_wcpdf, $woocommerce;

    // Get the order object
    $_order = $wpo_wcpdf->export->order;

    foreach ( $_order->get_items() as $item ) {
        // Added WC 3+ compatibility
        $quantity = method_exists( $item, 'get_quantity' ) ? $item->get_quantity() : $item['quantity'];
        $variation_id = method_exists( $item, 'get_variation_id' ) ? $item->get_variation_id() : $item['variation_id'];
        $_product = version_compare( WC_VERSION, '3.0', '<' ) ? wc_get_product( $item['product_id'] ) : $item->get_product();

        // Get the product object when it's a product variation ( Before version WC 3+)
        if ( version_compare( WC_VERSION, '3.0', '<' ) ) 
            if ($item['variation_id'] > 0) $_product = wc_get_product( $item['variation_id'] );

        // Get prices
        $sale_price = $_product->get_sale_price();
        $regular_price = $_product->get_regular_price();

        // Only when sale price exits
        if ( ! empty( $sale_price ) && $sale_price > 0 ) {
            $discount = ($regular_price - $sale_price) * $item->get_quantity();
            $discount_total += $discount;
        }

    }
    if ( $discount_total > 0 ) {
        $display_discount = '<tr class="cart-discount">
            <th>'. __( 'Total you saved :', 'woocommerce' ) .'</th>
            <td data-title=" '. __( 'Total you saved :', 'woocommerce' ) .' ">' . wc_price( $discount_total + $_order->get_total_discount() ) .'</td>
        </tr>';
    }

?>

Then you can use it where you want in the template to output it, this way (inside html):

<?php echo $display_discount; ?>

Or (inside php code):

echo $display_discount;

This code is tested and works.