Code-Snippets-Functions/Execute a function on a child site/WooCommerce/progressive-discount-based-on-cart-subtotal-if-there-are-no-discount.txt

// Conditional function that check if there are cart items "on sale"
function has_items_on_sale( $cart ) {
    // Loop through cart items
    foreach ( $cart->get_cart() as $item ) {
        if ( $item['data']->is_on_sale() ) {
            return true;
        }
    }
    return false;
}

// Progessive discount based on cart subtotal
add_action( 'woocommerce_cart_calculate_fees', 'subtotal_based_progressive_discount' );
function subtotal_based_progressive_discount( $cart ) {
    if( is_admin() && !defined('DOING_AJAX') ) {
        return;
    }
    // Exit if a cart item is on sale
    if( has_items_on_sale( $cart ) ) {
        return;
    }
    // Exit if a coupon has been applied to cart
    if( $cart->get_applied_coupons() ) {
        return;
    }

    $subtotal = $cart->subtotal;
    $percent  = 0;

    if( $subtotal >= 3000 && $subtotal < 10000 ) {
        $percent = 2; // 2 %
    } elseif( $subtotal >= 10000 ) {
        $percent = 5; // 5 %
    }

    if( $percent > 0 ) {
        $cart->add_fee( __('Sale') . " {$percent}%", -($subtotal * $percent / 100) );
    }
}