WooCommerce

add_action('woocommerce_before_add_to_cart_button', function () {
    global $product;
    $wf = get_post_meta($product->get_id(), '_fc_workflow_id', true)
          ?: get_option('fc_default_workflow_id');
    if (!$wf) return;

    $pk   = esc_js(get_option('fc_publishable_key'));
    $pid  = (int) $product->get_id();

    echo "<div id='fc-slot-{$pid}'></div>";
    echo "<input type='hidden' name='fc_job_id' id='fc-job-id-{$pid}' value=''>";

    wp_enqueue_script('filecheck', "https://cdn.filecheck.io/element/{$pk}/filecheck.js", [], null, true);

    wp_add_inline_script('filecheck', "
        (function () {
            var started = Date.now();
            (function tick() {
                if (window.Filecheck && window.Filecheck.mount) {
                    var el = window.Filecheck.mount({
                        publishableKey: '{$pk}',
                        workflowId:     '{$wf}',
                        mountSelector:  '#fc-slot-{$pid}'
                    });
                    if (el) el.on('status', function (e) {
                        document.getElementById('fc-job-id-{$pid}').value = e.jobId || '';
                    });
                    return;
                }
                if (Date.now() - started < 10000) setTimeout(tick, 50);
            })();
        })();
    ");
});

add_filter('woocommerce_add_to_cart_validation', function ($valid, $product_id) {
    if (get_post_meta($product_id, '_fc_required', true) && empty($_POST['fc_job_id'])) {
        wc_add_notice('Please upload and validate your file first.', 'error');
        return false;
    }
    return $valid;
}, 10, 2);

add_filter('woocommerce_add_cart_item_data', function ($data) {
    if (!empty($_POST['fc_job_id']))
        $data['fc_job_id'] = sanitize_text_field($_POST['fc_job_id']);
    return $data;
});

add_action('woocommerce_checkout_create_order_line_item', function ($item, $key, $values) {
    if (!empty($values['fc_job_id']))
        $item->update_meta_data('Filecheck Job', $values['fc_job_id']);
}, 10, 3);