commerce_line_item_ajax_recalculate.module

<?php

/**
 * @file
 * Recalculates the sell price of the line item on Add to Cart form.
 */


/**
 * Implements hook_form_BASE_FORM_ID_alter().
 */
function commerce_line_item_ajax_recalculate_form_commerce_cart_add_to_cart_form_alter(&$form, &$form_state, $form_id) {
  // AJAXify line item elements.
  foreach (element_children($form['line_item_fields']) as $field_name) {
    if (!empty($form['line_item_fields'][$field_name]['#commerce_cart_settings']['field_access'])) {
      // Append an AJAX callback to each of the line item field widgets
      // so that we can dynamically calculate pricing on change events.
      $field_lang = $form['line_item_fields'][$field_name]['#language'];
      if (count(element_children($form['line_item_fields'][$field_name][$field_lang])) > 0) {
        foreach (element_children($form['line_item_fields'][$field_name][$field_lang]) as $delta) {
          foreach (element_children($form['line_item_fields'][$field_name][$field_lang][$delta]) as $sub_field) {
            $form['line_item_fields'][$field_name][$field_lang][$delta][$sub_field]['#ajax'] = array(
              'callback' => '_commerce_line_item_ajax_recalculate_line_item_field_refresh',
            );
          }
        }
      } else {
        $form['line_item_fields'][$field_name][$field_lang]['#ajax'] = array(
          'callback' => '_commerce_line_item_ajax_recalculate_line_item_field_refresh',
        );
      }
    }
  }
}

/**
 * Ajax callback: returns AJAX commands when line items fields change.
 */
function _commerce_line_item_ajax_recalculate_line_item_field_refresh($form, &$form_state) {
  $line_item = $form_state['line_item'];
  $line_item_wrapper = entity_metadata_wrapper('commerce_line_item', $line_item);

  // Pass the line item object to rules to calculate the sale price.
  drupal_alter('commerce_product_calculate_sell_price_line_item', $line_item);
  rules_invoke_event('commerce_product_calculate_sell_price', $line_item);

  // Load a product wrapper and pseudo replace the commerce_price value
  // so that we can generate a new render array.
  $product = commerce_product_load($form_state['default_product_id']);
  $product_wrapper = entity_metadata_wrapper('commerce_product', $product);
  try {
    $product_wrapper->commerce_price->set($line_item_wrapper->commerce_unit_price->value());
  }
  catch (Exception $ex) {
    // Leave the commerce_price field untouched if there were issues setting
    // the value.
  }

  // Determine the appropriate class wrappers to use when replacing the price.
  $replacement_class = drupal_html_class(implode('-', array($form_state['context']['class_prefix'], 'product', 'commerce_price')));

  $classes = array(
    'commerce-product-field',
    drupal_html_class('commerce-product-field-' . 'commerce_price'),
    drupal_html_class('field-' . 'commerce_price'),
    $replacement_class,
  );

  $element = field_view_field('commerce_product', $product, 'commerce_price', $form_state['context']['view_mode']);

  // Append the prefix and suffix around existing values if necessary.
  $element += array('#prefix' => '', '#suffix' => '');
  $element['#prefix'] = '<div class="' . implode(' ', $classes) . '">' . $element['#prefix'];
  $element['#suffix'] .= '</div>';

  // Replace the rendered commerce product price field via AJAX.
  $commands[] = ajax_command_replace('.' . $form_state['context']['class_prefix'] . '-product-commerce-price', drupal_render($element));

  return array('#type' => 'ajax', '#commands' => $commands);
}