Add calculated saving total in Woocommerce order t

Question

In Woocommerce, I am using the following code to calculate and display 'Total Saving' on the order in Cart and checkout pages:

function wc_discount_total_30() {
    global $woocommerce;
    $discount_total = 0;
    foreach ( $woocommerce->cart->get_cart() as $cart_item_key => $values) {
        $_product = $values['data'];
        if ( $_product->is_on_sale() ) {
            $regular_price = $_product->get_regular_price();
            $sale_price = $_product->get_sale_price();
            $discount = ($regular_price - $sale_price) * $values['quantity'];
            $discount_total += $discount;
        }
    }
    if ( $discount_total > 0 ) {
        echo '<tr class="cart-discount">
        <th>'. __( 'Saved', 'tsavedis' ) .'</th>
        <td data-title=" '. __( 'Saved', 'tsavedis' ) .' ">'
        . wc_price( $discount_total + $woocommerce->cart->discount_cart ) .'</td>
        </tr>';
    }
}

// Hook our values to the Basket and Checkout pages
add_action( 'woocommerce_cart_totals_after_order_total', 'wc_discount_total_30', 99);
add_action( 'woocommerce_review_order_after_order_total', 'wc_discount_total_30', 99);

I need to display this total saving in 'Order Edit' page at backend as a custom field.
How to do that ?

Answer 1

Here is the way to add the same thing to orders totals table:

// Display the chosen delivery information
add_filter( 'woocommerce_get_order_item_totals', 'add_saving_total_order_totals', 10, 3 );
function add_saving_total_order_totals( $total_rows, $order, $tax_display ) {;
    $saving_total = 0;

    // Loop through Order items
    foreach($order->get_items() as $item ){
        $product = $item->get_product();

        if( $product->is_on_sale() ){
            $regular_price   = (float) $product->get_regular_price();
            $active_price    = (float) $product->get_price();

            $saving_total   += ($regular_price - $active_price) * $item->get_quantity();
        }
    }

    if( $saving_total > 0 ) {
        $discount_total = $order->get_discount_total();

        $label  = __( 'Saved', 'tsavedis' );
        $value  = wc_price( $saving_total + $discount_total );

        $total_rows['saving'] = array( 'label' => $label,'value' => $value );
    }
    return $total_rows;
}

Code goes in function.php file of your active child theme (or active theme). tested and works.