Jak dodać rabat na podstawie ilości sztuk w WooCommerce?

				
					/**
 * Autor: Greatsite.pl 
 * Funkcjonalność: Rabat na podstawie ilości sztuk w WooCommerce.
 */

define('DISCOUNTS', [
    10 => 5,  // 10 sztuk - 5% rabatu
    25 => 15, // 25 sztuk - 15% rabatu
    50 => 25, // 50 sztuk - 25% rabatu
]);

function gr8_custom_quantity_based_discount_in_cart() {
    if ( ! class_exists( 'WooCommerce' ) ) return;

    $woocommerce = WC();
    $total_quantity = 0;
    $total_brutto = 0;
    $cart_items = $woocommerce->cart->get_cart();

    foreach ( $cart_items as $cart_item ) {
        $total_quantity += $cart_item['quantity'];
        $total_brutto += $cart_item['line_total'];
    }

    $discount_percentage = 0;
    $discount_description = '';

    foreach ( DISCOUNTS as $threshold => $percentage ) {
        if ( $total_quantity >= $threshold ) {
            $discount_percentage = $percentage;
            $discount_description = sprintf('Zniżka: -%d%% za %d sztuk produktu', $discount_percentage, $total_quantity);
        }
    }

    if ( $discount_percentage > 0 ) {
        $discount = round( $total_brutto * ( $discount_percentage / 100 ), 4 );
        $woocommerce->cart->add_fee( $discount_description, -$discount );
    }
}

add_action( 'woocommerce_cart_calculate_fees', 'gr8_custom_quantity_based_discount_in_cart' );

function gr8_custom_discount_message() {
    global $product, $woocommerce;

    if ( ! class_exists( 'WooCommerce' ) ) return;

    $total_quantity = 0;
    $cart_items = $woocommerce->cart->get_cart();

    foreach ( $cart_items as $cart_item ) {
        if ( $cart_item['product_id'] == $product->get_id() ) {
            $total_quantity += $cart_item['quantity'];
        }
    }

    $next_threshold = null;
    $discount_percentage = 0;

    foreach (DISCOUNTS as $threshold => $percentage) {
        if ($total_quantity < $threshold) {
            $next_threshold = $threshold;
            $discount_percentage = $percentage;
            break;
        }
    }

    if ( !is_null( $next_threshold ) ) {
        echo '<div class="woocommerce-info">';
        echo sprintf('Kup jeszcze %d sztuk, aby otrzymać %d%% zniżki!', ($next_threshold - $total_quantity), $discount_percentage);
        echo '</div>';
    }
}

add_action( 'woocommerce_before_add_to_cart_form', 'gr8_custom_discount_message' );