Woocommerce simple product kaucija

<?php

// doda kaucija field pod tab Općenito
function wb_add_kaucija_field() {
    global $post;

    $product = wc_get_product($post->ID);

    if ($product->is_type('simple')) {
        echo '<div class="options_group">';
        woocommerce_wp_text_input(
            array(
                'id' => 'kaucija',
                'label' => __('Kaucija', 'woocommerce'),
                'placeholder' => __('0.00', 'woocommerce')
            )
        );
        echo '</div>';
    }
}
add_action('woocommerce_product_options_general_product_data', 'wb_add_kaucija_field');

// save
function wb_save_kaucija_field($post_id) {
    $kaucija = isset($_POST['kaucija']) ? wc_clean(wp_unslash($_POST['kaucija'])) : '';
    update_post_meta($post_id, 'kaucija', sanitize_text_field($kaucija));
}
add_action('woocommerce_process_product_meta', 'wb_save_kaucija_field');

// kalkulacija cijene
function wb_calculate_total_product_price($price, $product) {
    $kaucija = get_post_meta($product->get_id(), 'kaucija', true);
    $kaucija = floatval($kaucija);

    if ($kaucija) {
        $price += $kaucija;
    }

    return $price;
}
add_filter('woocommerce_get_price', 'wb_calculate_total_product_price', 10, 2);