bulk discoutn for woo category

<?php

add_action( 'woocommerce_cart_calculate_fees', 'discount_for_special_sale_category', 10, 1 );

function discount_for_special_sale_category( $cart ) {
    if ( is_admin() && ! defined( 'DOING_AJAX' ) )
        return;

    // Initializing
    $discount = 0;
    $saved_amount = 0;
    $special_sale_category = 'special-sale';

    // Iterating through each cart item
    foreach ( $cart->get_cart() as $cart_item ) {
        // Get the product categories
        $product_categories = get_the_terms( $cart_item['product_id'], 'product_cat' );

        // Iterating through each product category
        foreach ( $product_categories as $product_category ) {
            // Check if the product category is "special-sale"
            if ( $product_category->slug == $special_sale_category ) {
                // Calculate the discount
                if ( $cart_item['quantity'] >= 3 ) {
                    $discount = $cart_item['line_total'] * 0.6;
                } elseif ( $cart_item['quantity'] >= 1 ) {
                    $discount = $cart_item['line_total'] * 0.5;
                }

                // Calculate the saved amount
                $saved_amount += $discount;
            }
        }
    }

    // Add the discount
    if ( $saved_amount > 0 ) {
        $cart->add_fee( __( 'Sonderrabatt für Kategorie "Special Sale"', 'woocommerce' ), -$saved_amount );
    }


}