Discounting not Working properly.

So I am creating a function which will add 5% discount when a certain payment gateway is selected.

// Add the discount if the Razorpay payment method is selected
function razorpay_online_payment_discount( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) ) {
        return;
    }

    $chosen_payment_method = WC()->session->get('chosen_payment_method');

    // Check if payment method is set
    if ( ! isset( $chosen_payment_method ) ) {
        return;
    }

    $discount_percentage = 5;

    // Remove existing fee if any
    foreach ( $cart->get_fees() as $fee_key => $fee ) {
        if ( 'online_payment_discount' === $fee->get_id() ) {
            $cart->remove_fee( $fee_key );
            break;
        }
    }

if ( 'razorpay' === $chosen_payment_method ) {
    // Only consider the subtotal for calculating the discount
    $subtotal = $cart->subtotal;
    $discount = round( $subtotal * ( $discount_percentage / 100 ), 2 ); 
    $cart->add_fee( __( 'Online Payment Discount', 'woocommerce' ), -$discount, false );
}

}
add_action( 'woocommerce_cart_calculate_fees', 'razorpay_online_payment_discount', 10, 1 );

// Update the cart/checkout page when the payment method is changed
function razorpay_online_payment_discount_refresh() {
    if ( ! is_checkout() && ! is_cart() ) {
        return;
    }

    wc_clear_notices(); // Clear any displayed notices
    WC()->session->set( 'refresh_totals', true ); // Trigger update of totals

    ?>
    <script type="text/javascript">
        (function( $ ) {
            $(document.body).on('change', 'input[name="payment_method"]', function() {
                $('body').trigger('update_checkout');
            });
        })(jQuery);
    </script>
    <?php
}
add_action( 'wp_footer', 'razorpay_online_payment_discount_refresh', 50 );

Now this code is working fine but tere is an issue. Lets say the cart value is 798.00 then 5% of it should be 39.90 but the code is making it 41.10

I tried another code where instead of using add_fee function i tried to do it outside just to show text

  if ( 'razorpay' === $chosen_payment_method ) {
        $subtotal = WC()->cart->subtotal + WC()->cart->shipping_total;
        $discount = round( $subtotal * ( $discount_percentage / 100 ), 2 ); // Round the discount amount to two decimal places
        $formatted_discount = wc_price( $discount );

        echo '<tr class="discount-row">';
        echo '<th>' . __( 'Online Payment Discount', 'woocommerce' ) . '</th>';
        echo '<td>- ' . $formatted_discount . '</td>';
        echo '</tr>';
    }

This code works fine and gives me proper 39.90 value. Something is happening in the backend which i am not able to figure out how to solve this.

I am using these settings in woocommerce:

• Prices entered with tax -> Yes, I will enter prices inclusive of tax
• Rounding -> Rounding Round tax at subtotal level, instead of rounding per line
• Display prices during cart and checkout -> Including Tax

Any help would be appreciated to find what can be done to debug this.
Here is a cart var_dump if this helps – https://pastebin.com/raw/47LKk0VR

• This topic was modified 2 years, 11 months ago by nawafgantare.