Woocommerce中成本更低的产品的购物车折扣

如何在产品购物车中为成本较低的产品应用折扣?

例如:
我的购物车里有两个产品:一个150美元,一个200美元。我只想对价格更低的产品打10%的折扣,在这种情况下是第一个。

我有此代码,但它仅适用于购物车中的第二个产品:

add_filter( 'woocommerce_before_calculate_totals', 'discount_on_2nd_cart_item', 10, 1 );
function discount_on_2nd_cart_item( $cart_object ) {

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

    // Initialising
    $count = 0;
    $discount = 0.10; // 10 %
    $discounted = 0;
    // Iterating though each cart items
    foreach ( $cart_object->get_cart() as $cart_item ) {
        $count++;
        if( 2 == $count){ // Second item only
            $price = $cart_item['data']->get_price(); // product price
            $discounted_price = $price - ($price * $discount); // calculation
            $discounted = $price - $discounted_price;
            // Set the new price
            //$cart_item['data']->set_price( $discounted_price );
            break; // stop the loop
        }
    }

    $cart_object->add_fee( "Discount (10%) on second product", -$discounted, true );
}