Agregue un precio calculado de producto personalizado al carrito de Woocommerce

En woocommerce he agregado un campo de texto adicional antes de agregar al botón del carrito para agregar un cargo personalizado en la compra del producto.

Este complemento agregará un campo de texto adicional a la página de un solo producto y calculará el total más el cargo adicional.

Mi problema es que no puedo agregar totales de carrito personalizados y el cargo adicional se agrega antes de los totales

Lo intentéwoocommerce_cart_calculate_fees pero sin suerte solo muestra$0 en totales

ódigo @PHP:

 /**
 * Check if woocommerce is active and or installed.
 */

if ( class_exists( 'WooCommerce' ) || in_array( 'woocommerce/woocommerce.php', apply_filters( 'active_plugins', get_option( 'active_plugins' ) ) ) || function_exists( 'WC' ) && is_object( WC() ) && is_a( WC(), 'WooCommerce' )  )
{

/**
 * Style and Ajax script.
 */
    add_action('woocommerce_single_product_summary','extra_enqueue_scripts');

        function  extra_enqueue_scripts()
        {
            wp_enqueue_style('custom_style', plugins_url('/assets/css/custom_style.css', __FILE__));

            wp_register_script( 'item_add', plugins_url('/assets/js/item_add.js', __FILE__), array('jquery'), false, true ); 
            wp_enqueue_script('item_add'); 

            $array_to_be_sent = array( 'ajax_file_path' => admin_url('admin-ajax.php')); 

            wp_localize_script( 'item_add', 'wdm_object', $array_to_be_sent);

        }


/**
 * Add Text field Before add to cart button.
 */     

    add_action( 'woocommerce_before_add_to_cart_button', 'extra_add_custom_field', 0 );

        function extra_add_custom_field() 
        {
          $currency = get_woocommerce_currency_symbol();
          echo "<div class='custom-text text'><p>Extra Charge ($currency):</p>
          <input type='text' name='custom_price' value='' placeholder='e.g. 10' title='Custom Text' class='custom_price text_custom text'></div>";

        } 

/**
 * Add ajax callback function to get data
 * and add that data to session.
 */             

    add_action('wp_ajax_extra_add_user_custom_data_options_callback', 'extra_add_user_custom_data_options_callback');
    add_action('wp_ajax_nopriv_extra_add_user_custom_data_options_callback', 'extra_add_user_custom_data_options_callback');

        function extra_add_user_custom_data_options_callback()
        {
          $user_custom_data_values = (float)sanitize_text_field($_POST['custom_price']);
          session_start();
          $_SESSION['user_custom_data'] = $user_custom_data_values;
          die();
        }


/**
 * Add data to cart from session and then destroy session.
 */ 

    add_filter('woocommerce_add_cart_item_data','extra_add_custom_field_data',1,2);

        function extra_add_custom_field_data($cart_item_data,$product_id)
        {
            global $woocommerce;
            session_start();    
            if (isset($_SESSION['user_custom_data'])) 
            {
                $option    = $_SESSION['user_custom_data'];       
                $new_value = array('user_custom_data_value' => $option);
            }
            if(empty($option))
            {               
                return $cart_item_data;
            }
            else
            {    
                if(empty($cart_item_data))
                {
                    return $new_value;
                }
                else
                {
                    return array_merge($cart_item_data,$new_value);
                }
            }
            unset($_SESSION['user_custom_data']); 
        }


/**
 * Derive cart Item from session.
 */         

    add_filter('woocommerce_get_cart_item_from_session', 'extra_get_cart_items_from_session', 1, 3 );

        function extra_get_cart_items_from_session($item,$values,$key)
        {
            if (array_key_exists( 'user_custom_data_value', $values ) )
            {
                $item['user_custom_data_value'] = $values['user_custom_data_value'];
            }       
            return $item;
        }

/** 
 * Add extra price into product regular price.
 * Calculate extra price before checkout.
 */         

    add_action( 'woocommerce_before_calculate_totals', 'extra_price_add_custom_price' );

        function extra_price_add_custom_price( $cart_object ) 
        {   
          foreach ( $cart_object->get_cart() as $hash => $value )       
          { 
            if(!empty($value['user_custom_data_value']) && $value['data']->is_on_sale())
            {   
                $newprice = $value['data']->get_sale_price() + $value['user_custom_data_value'];
                $value['data']->set_price((float)( $newprice ));
            }
            elseif(!empty($value['user_custom_data_value']))
            {
                $newprice = $value['data']->get_regular_price() + $value['user_custom_data_value'];
                $value['data']->set_price((float)( $newprice ));
            }
          }
        }


/**
 * Render extra charge in cart table.
 */         

    add_filter('woocommerce_checkout_cart_item_quantity','extra_add_user_custom_option_from_session_into_cart',1,3); 
    add_filter('woocommerce_cart_item_price','extra_add_user_custom_option_from_session_into_cart',1,3);

        function extra_add_user_custom_option_from_session_into_cart($product_name, $values, $cart_item_key )
        {
            if(count($values['user_custom_data_value']) > 0)
            {
                $currency      = get_woocommerce_currency_symbol();
                $product_price = wc_get_product( $values['product_id'] );
                if($product_price->is_on_sale())
                {
                    $price = $product_price->get_sale_price().'&nbsp;(On Sale!)';
                }
                else
                {
                    $price = $product_price->get_regular_price();
                }

                $custom_items  = $currency.$price."<br>";
                $custom_items .= $currency.$values['user_custom_data_value'].'&nbsp;';
                $custom_items .= __("Extra Charge", "woocommerce" );
                return $custom_items;
            }
            else
            {
                return $product_name;
            }
        }

/**
 * Remove custom data if quantity is zero.
 */ 

    add_action('woocommerce_before_cart_item_quantity_zero','extra_remove_user_custom_data_options_from_cart',1,1);

        function extra_remove_user_custom_data_options_from_cart($cart_item_key)
        {
            global $woocommerce;
            $cart = $woocommerce->cart->get_cart();
            foreach( $cart as $key => $values)
            {
                if ( $values['user_custom_data_value'] == $cart_item_key )
                {
                    unset( $woocommerce->cart->cart_contents[ $key ] );
                }
            }
        }       



/**
 * Add custom data to order meta after checkout.
 */ 

     add_action('woocommerce_add_order_item_meta','extra_add_values_to_order_item_meta',1,2);

        function extra_add_values_to_order_item_meta($item_id, $values)
        {
            global $woocommerce,$wpdb;
            $user_custom_values = $values['user_custom_data_value'];
            if(!empty($user_custom_values))
            {
                $currency = get_woocommerce_currency_symbol();
                wc_add_order_item_meta($item_id,'Extra Charge',$currency.$user_custom_values);  
            }
        }
} 

else 

{

/**
 * Generate error notice if woocommerce is not detected.
 */ 

    add_action( 'admin_notices', 'extra_no_woocommerce' );

        function extra_no_woocommerce()
        {
            $err_text = site_url()."/wp-admin/plugin-install.php?tab=plugin-information&plugin=woocommerce&TB_iframe=true";
            ?>
            <div class="error notice">
            <p><?php echo sprintf("Please Activate or <a href='%s' style='color:green;'>Install Woocommerce</a> to use extra field for product charge plugin",$err_text); ?></p>
            </div>
           <?php
        }
}

JS Código

jQuery(document).ready(function(){
        jQuery('.single_add_to_cart_button').click(function(){
          jQuery.ajax({
                    url: wdm_object.ajax_file_path,
                    type: "POST",
                    data: {
                            action:'add_user_custom_data_options_callback', 
                            custom_price : jQuery('.custom_price').val()
                          },
                    async : false,
                    success: function(data){
                        jQuery('.single_add_to_cart_button').text('Added to cart');
                    }
                });
 })
 });

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