Coupon discount on product regular price (not sale price)

Question

In WooCommerce, I have products with a regular price of X and a sales price of Y. I would like to add a coupon with a code for a $45.00 discount to be taken from the regular price X.

I would like the coupon to disregard the sale price so I get X-$45 NOT Y-$45. But when the coupon is not applied price Y is used.

I found the following which works for percentage discounts, but I can't seem to make it work for a fixed product discount price.

add_filter('woocommerce_coupon_get_discount_amount', 'woocommerce_coupon_get_discount_amount', 10, 5 );
function woocommerce_coupon_get_discount_amount( $discount, $discounting_amount, $cart_item, $single, $coupon ) {
    if ($coupon->type == 'percent_product' || $coupon->type == 'percent') {
        global $woocommerce;
        $cart_total = 0;

        foreach ( $woocommerce->cart->get_cart() as $cart_item_key => $cart_item ) {

         $variable_product1= new WC_Product_Variation( $cart_item["variation_id"] );

         $cart_total += $variable_product1 ->regular_price * $cart_item['quantity'];
        } 
        $discount = round( ( $cart_total / 100 ) * $coupon->amount, $woocommerce->cart->dp );
        return $discount;
    }
    return $discount;
}

Answer 1

This seems to check for a coupon and then change the cart price to regular price rather than discounted price (obtained from woocommerce dynamic pricing in this application) prior to applying the coupon. placed in functions.php

add_action( 'woocommerce_before_calculate_totals', 'add_custom_price', 10, 1);
function add_custom_price( $cart_object) {

    global $woocommerce;

    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    $coupon = False;

    if ($coupons = WC()->cart->get_applied_coupons()  == False ) 
      $coupon = False;
    else {
        foreach ( WC()->cart->get_applied_coupons() as $code ) {
          $coupons1 = new WC_Coupon( $code );
          if ($coupons1->type == 'percent_product' || $coupons1->type == 'percent')
            $coupon = True;
        }
    }

    if ($coupon == True)
        foreach ( $cart_object->get_cart() as $cart_item ) 
        {
            $price = $cart_item['data']->regular_price;
            $cart_item['data']->set_price( $price );
        }
}