Discount depends on Woocemmerce payment method

add_action( 'woocommerce_cart_calculate_fees', 'wc_payment_based_discount', 10, 1 );
function wc_payment_based_discount( $cart ) {

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

  // Check if a coupon code has been applied
  if ( WC()->cart->has_discount() )
    return;

  // Check if the product "Wallet Topup" is in the cart
  $wallet_topup_found = false;
  foreach ( $cart->get_cart() as $cart_item ) {
    if ( $cart_item['data']->get_name() == 'Wallet Topup' ) {
      $wallet_topup_found = true;
      break;
    }
  }

  if ( $wallet_topup_found )
    return;

    // Check if the product is on sale
$product_on_sale = false;
foreach ( $cart->get_cart() as $cart_item ) {
  if ( $cart_item['data']->is_on_sale() ) {
    $product_on_sale = true;
    break;
  }
}

if ( $product_on_sale )
  return;

  // Get chosen payment method
  $payment_method = WC()->session->get( 'chosen_payment_method' );

  if ( $payment_method == 'wallet' ) {
    $discount_percent = 2;
  } elseif ( $payment_method == 'cod' ) {
    $discount_percent = 2;
  } else {
    $discount_percent = 0;
  }

  // Calculate discount amount
  $discount_amount = $cart->get_subtotal() * ( $discount_percent / 100 );
  $cart->add_fee( 'Discount', - $discount_amount, true );
}