Facebook Product Feed dynamic attribute for WooCommerce

/*
 * START patch for minimum price meta on bundle products
 */
// We will create a new meta or update the existing one each time we update our products
add_action('save_post_product', 'update_bundle_product_min_price', 10, 1);
function update_bundle_product_min_price( $post_id) {
    $product = wc_get_product( $post_id );
    if($product->get_type() == 'grouped') {
        $bundled_items = $product->get_children();
        // Verify that the product bundle has bundle items
        if(count($bundled_items) > 0) {
            $lower_price = min_price_in_bundle($bundled_items);
            update_post_meta($post_id,'_min_group_product_price',$lower_price);
        }
    } else if ($product->get_type() == 'composite') {
        update_post_meta($post_id,'_min_group_product_price',get_post_meta($post_id,'_price',true));
    } else if($product->get_type() == 'variable'){
       update_post_meta($post_id,'_min_group_product_price',get_post_meta($post_id,'_min_variation_price',true));
    } else {
       update_post_meta($post_id,'_min_group_product_price',get_post_meta($post_id,'_regular_price',true));
    }
}
// Small helper function to find the cheapest product
function min_price_in_bundle($bundle) {
    return min(array_map(function($b){
        return wc_get_product($b)->get_price();
    },$bundle));
}
/*
 * END patch for minimum price meta on bundle products
 */