<?php

/**
 * @file
 * Enables the creation of webforms and questionnaires.
 */

use Drupal\Component\Utility\Unicode;
use Drupal\Component\Serialization\Json;
use Drupal\Core\Access\AccessResult;
use Drupal\Core\Asset\AttachedAssetsInterface;
use Drupal\Core\Breadcrumb\Breadcrumb;
use Drupal\Core\Database\Query\AlterableInterface;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Session\AccountInterface;
use Drupal\Core\Url;
use Drupal\file\Entity\File;
use Drupal\file\FileInterface;
use Drupal\webform\Entity\Webform;
use Drupal\webform\Entity\WebformSubmission;
use Drupal\webform\Element\WebformMessage;
use Drupal\webform\Plugin\Field\FieldType\WebformEntityReferenceItem;
use Drupal\webform\Plugin\WebformElement\ManagedFile;
use Drupal\webform\Utility\WebformArrayHelper;
use Drupal\webform\WebformInterface;
use Drupal\webform\WebformSubmissionForm;

module_load_include('inc', 'webform', 'includes/webform.libraries');
module_load_include('inc', 'webform', 'includes/webform.options');
module_load_include('inc', 'webform', 'includes/webform.translation');

/**
 * Implements hook_help().
 */
function webform_help($route_name, RouteMatchInterface $route_match) {
  // Get path from route match.
  $path = preg_replace('/^' . preg_quote(base_path(), '/') . '/', '/', Url::fromRouteMatch($route_match)->setAbsolute(FALSE)->toString());
  if (!in_array($route_name, ['system.modules_list']) && strpos($route_name, 'webform') === FALSE && strpos($path, '/webform') === FALSE) {
    return NULL;
  }

  /** @var \Drupal\webform\WebformHelpManagerInterface $help_manager */
  $help_manager = \Drupal::service('webform.help_manager');
  if ($route_name == 'help.page.webform') {
    $build = $help_manager->buildIndex();
  }
  else {
    $build = $help_manager->buildHelp($route_name, $route_match);
  }

  if ($build) {
    $renderer = \Drupal::service('renderer');
    $config = \Drupal::config('webform.settings');
    $renderer->addCacheableDependency($build, $config);
    return $build;
  }
  else {
    return NULL;
  }
}

/**
 * Implements hook_modules_installed().
 */
function webform_modules_installed($modules) {
  // Add webform paths when the path.module is being installed.
  if (in_array('path', $modules)) {
    /** @var \Drupal\webform\WebformInterface[] $webforms */
    $webforms = Webform::loadMultiple();
    foreach ($webforms as $webform) {
      $webform->updatePaths();
    }
  }

  // Check HTML email provider support as modules are installed.
  /** @var \Drupal\webform\WebformEmailProviderInterface $email_provider */
  $email_provider = \Drupal::service('webform.email_provider');
  $email_provider->check();
}

/**
 * Implements hook_modules_uninstalled().
 */
function webform_modules_uninstalled($modules) {
  // Remove uninstalled module's third party settings from admin settings.
  $config = \Drupal::configFactory()->getEditable('webform.settings');
  $third_party_settings = $config->get('third_party_settings');
  foreach ($modules as $module) {
    unset($third_party_settings[$module]);
  }
  $config->set('third_party_settings', $third_party_settings);
  $config->save();

  // Check HTML email provider support as modules are ininstalled.
  /** @var \Drupal\webform\WebformEmailProviderInterface $email_provider */
  $email_provider = \Drupal::service('webform.email_provider');
  $email_provider->check();
}

/**
 * Implements hook_cron().
 */
function webform_cron() {
  $config = \Drupal::config('webform.settings');
  \Drupal::entityTypeManager()->getStorage('webform_submission')->purge($config->get('purge_settings.cron_size'));
}

/**
 * Implements hook_local_tasks_alter().
 */
function webform_local_tasks_alter(&$local_tasks) {
  if (isset($local_tasks['config_translation.local_tasks:entity.webform.config_translation_overview'])) {
    // Change 'Translate' base route from 'entity.webform.edit_form'
    // to 'entity.webform.canonical' because by default config entities don't
    // have canonical views but the webform entity does.
    $local_tasks['config_translation.local_tasks:entity.webform.config_translation_overview']['title'] = 'Translate';
    $local_tasks['config_translation.local_tasks:entity.webform.config_translation_overview']['base_route'] = 'entity.webform.canonical';
  }
}

/**
 * Implements hook_menu_local_tasks_alter().
 */
function webform_menu_local_tasks_alter(&$data, $route_name) {
  // Change 'Translate webform' tab to be just label 'Translate'.
  if (strpos($route_name, 'entity.webform.') === 0) {
    if (isset($data['tabs'][0]['config_translation.local_tasks:entity.webform.config_translation_overview']['#link']['title'])) {
      $data['tabs'][0]['config_translation.local_tasks:entity.webform.config_translation_overview']['#link']['title'] = t('Translate');
    }
  }

  // ISSUE:
  // Devel routes do not use 'webform' parameter which throws the below error.
  // Some mandatory parameters are missing ("webform") to generate a URL for
  // route "entity.webform_submission.canonical"
  //
  // WORKAROUND:
  // Make sure webform parameter is set for all routes.
  if (strpos($route_name, 'entity.webform_submission.devel_') === 0 || $route_name === 'entity.webform_submission.token_devel') {
    foreach ($data['tabs'] as $tab_level) {
      foreach ($tab_level as $tab) {
        /** @var Drupal\Core\Url $url */
        $url = $tab['#link']['url'];
        $tab_route_name = $url->getRouteName();
        $tab_route_parameters = $url->getRouteParameters();

        if (strpos($tab_route_name, 'entity.webform_submission.devel_') !== 0) {
          $webform_submission = WebformSubmission::load($tab_route_parameters['webform_submission']);
          $url->setRouteParameter('webform', $webform_submission->getWebform()->id());
        }
      }
    }
  }
}

/**
 * Implements hook_form_alter().
 */
function webform_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  if (strpos($form_id, 'webform_') === FALSE || strpos($form_id, 'node_') === 0) {
    return;
  }

  // Display editing original language warning.
  if (\Drupal::moduleHandler()->moduleExists('config_translation') && preg_match('/^entity.webform.(?:edit|settings|assets|access|handlers|third_party_settings)_form$/', \Drupal::routeMatch()->getRouteName())) {
    /** @var \Drupal\webform\WebformInterface $webform */
    $webform = \Drupal::routeMatch()->getParameter('webform');
    /** @var \Drupal\Core\Language\LanguageManagerInterface $language_manager */
    $language_manager = \Drupal::service('language_manager');

    // If current webform is translated, load the base (default) webform and apply
    // the translation to the elements.
    if ($webform->getLangcode() != $language_manager->getCurrentLanguage()->getId()) {
      $original_language = $language_manager->getLanguage($webform->getLangcode());
      $form['langcode_message'] = [
        '#type' => 'webform_message',
        '#message_type' => 'warning',
        '#message_message' => t('You are editing the original %language language for this webform.', ['%language' => $original_language->getName()]),
        '#message_close' => TRUE,
        '#message_storage' => WebformMessage::STORAGE_LOCAL,
        '#message_id' => $webform->id() . '.original_language',
        '#weight' => -100,
      ];
    }
  }

  // Don't include details toggle all for submission forms.
  $is_submission_form = ($form_state->getFormObject() instanceof WebformSubmissionForm);
  if (!$is_submission_form) {
    $form['#attributes']['class'][] = 'js-webform-details-toggle';
    $form['#attributes']['class'][] = 'webform-details-toggle';
    $form['#attached']['library'][] = 'webform/webform.element.details.toggle';
  }

  if ($is_submission_form) {
    $form['#after_build'][] = '_webform_form_after_build';
  }
}

/**
 * Alter webform after build.
 */
function _webform_form_after_build($form, FormStateInterface $form_state) {
  $form_object = $form_state->getFormObject();

  // Add contextual links and change theme wrapper to webform.html.twig
  // which includes 'title_prefix' and 'title_suffix' variables needed for
  // contextual links to appear.
  $form['#contextual_links']['webform'] = [
    'route_parameters' => ['webform' => $form_object->getEntity()->getWebform()->id()],
  ];
  $form['#theme_wrappers'] = ['webform'];
  return $form;
}

/**
 * Implements hook_system_breadcrumb_alter().
 */
function webform_system_breadcrumb_alter(Breadcrumb &$breadcrumb, RouteMatchInterface $route_match, array $context) {
  // Remove 'Webforms' prefix from breadcrumb links generated path breadcrumbs.
  // @see \Drupal\system\PathBasedBreadcrumbBuilder
  $path = Url::fromRouteMatch($route_match)->toString();
  if (strpos($path, '/admin/structure/webform/settings/') !== FALSE) {
    $links = $breadcrumb->getLinks();
    foreach ($links as $link) {
      $text = $link->getText();
      if (strpos($text, ((string) t('Webforms')) . ' ') == 0) {
        $text = str_replace(((string) t('Webforms')) . ': ', '', $text);
        $link->setText(Unicode::ucfirst($text));
      }
    }
  }

  // Fix 'Help' breadcrumb text.
  if ($route_match->getRouteName() == 'webform.help') {
    $links = $breadcrumb->getLinks();
    $link = end($links);
    $link->setText(t('Webforms'));
  }
}

/**
 * Implements hook_entity_delete().
 */
function webform_entity_delete(EntityInterface $entity) {
  // Delete saved export settings for a webform or source entity with the
  // webform field.
  if (($entity instanceof WebformInterface) || WebformEntityReferenceItem::getEntityWebformFieldName($entity)) {
    $name = 'webform.export.' . $entity->getEntityTypeId() . '.' . $entity->id();
    \Drupal::state()->delete($name);
  }
}

/**
 * Implements hook_mail().
 */
function webform_mail($key, &$message, $params) {
  // Never send emails when using devel generate to create 1000's of
  // submissions.
  if (\Drupal::moduleHandler()->moduleExists('devel_generate')
    && \Drupal\webform\Plugin\DevelGenerate\WebformSubmissionDevelGenerate::isGeneratingSubmissions()) {
    $message['send'] = FALSE;
  }

  $message['subject'] = $params['subject'];
  $message['body'][] = $params['body'];

  // Set the header's 'From' to the 'from_mail' so that the webform's email from
  // value is used instead of site's email address.
  // See: \Drupal\Core\Mail\MailManager::mail.
  if (!empty($params['from_mail'])) {
    $message['from'] = $params['from_mail'];
    $message['headers']['From'] = $params['from_mail'];
    $message['headers']['Reply-to'] = $params['from_mail'];
    $message['headers']['Return-Path'] = $params['from_mail'];
  }

  if (!empty($params['cc_mail'])) {
    $message['headers']['Cc'] = $params['cc_mail'];
  }
  if (!empty($params['bcc_mail'])) {
    $message['headers']['Bcc'] = $params['bcc_mail'];
  }
}

/**
 * Implements hook_mail_alter().
 */
function webform_mail_alter(&$message) {
  // Drupal hardcodes all mail header as 'text/plain' so we need to set the
  // header's 'Content-type' to HTML if the EmailWebformHandler's
  // 'html' flag has been set.
  // @see \Drupal\Core\Mail\MailManager::mail()
  // @see \Drupal\webform\Plugin\WebformHandler\EmailWebformHandler::getMessage().
  if (strpos($message['id'], 'webform') === 0) {
    if (isset($message['params']['html']) && $message['params']['html']) {
      $message['headers']['Content-Type'] = 'text/html; charset=UTF-8; format=flowed';
    }
  }
}

/**
 * Implements hook_page_attachments().
 */
function webform_page_attachments(&$page) {
  $route_name = Drupal::routeMatch()->getRouteName();
  $url = Url::fromRoute('<current>')->toString();

  // Attach global libraries only to webform specific pages.
  if (preg_match('/^(webform\.|^entity\.([^.]+\.)?webform)/', $route_name) || preg_match('#(/node/add/webform|/admin/help/webform)#', $url)) {
    // Attach theme specific library to webform routers so that we can tweak
    // the bartik.theme and seven.theme.
    $theme = \Drupal::theme()->getActiveTheme()->getName();
    if (file_exists(drupal_get_path('module', 'webform') . "/css/webform.theme.$theme.css")) {
      $page['#attached']['library'][] = "webform/webform.theme.$theme";
    }

    // Attach details element save open/close library.
    // This ensures pages without a webform will still be able to save the
    // details element state.
    if (\Drupal::config('webform.settings')->get('ui.details_save')) {
      $page['#attached']['library'][] = 'webform/webform.element.details.save';
    }
  }

  // Attach codemirror and select2 library to block admin to ensure that the
  // library is loaded by the webform block is placed using AJAX.
  if (strpos($route_name, 'block.admin_display') === 0) {
    $page['#attached']['library'][] = 'webform/webform.block';
  }
}

/**
 * Implements hook_css_alter().
 *
 * @see \Drupal\webform\WebformSubmissionForm::form
 */
function webform_css_alter(&$css, AttachedAssetsInterface $assets) {
  _webform_asset_alter($css, $assets, 'css', 'css');
}

/**
 * Implements hook_js_alter().
 *
 * @see \Drupal\webform\WebformSubmissionForm::form
 */
function webform_js_alter(&$javascript, AttachedAssetsInterface $assets) {
  _webform_asset_alter($javascript, $assets, 'javascript', 'js');
}

/**
 * Alter CSS or JavaScript assets to include custom webform assets.
 *
 * Note: CSS and JavaScript are not aggregated or minified to make it easier
 * for themers to debug and custom their code.  We could write the CSS and JS
 * to the 'files/css' and 'files/js' using the hash key and aggregrate them.
 *
 * @param array $items
 *   An array of all CSS or JavaScript being presented on the page.
 * @param \Drupal\Core\Asset\AttachedAssetsInterface $assets
 *   The assets attached to the current response.
 * @param string $type
 *   The type of asset being attached.
 * @param string $extension
 *   The asset file extension being attached.
 */
function _webform_asset_alter(array &$items, AttachedAssetsInterface $assets, $type, $extension) {
  $settings = $assets->getSettings();
  if (empty($settings['webform']['assets'][$type])) {
    return;
  }

  $path = drupal_get_path('module', 'webform');
  foreach ($settings['webform']['assets'][$type] as $id => $hash) {
    $key = "$path/$extension/webform.assets.$extension";
    if (isset($items[$key])) {
      $items[$key] = [
        'data' => base_path() . "webform/$id/assets/$type?v=$hash",
        'group' => 1000,
        'weight' => 1000,
      ] + $items[$key];
    }
  }
}

/**
 * Implements hook_file_access().
 *
 * @see file_file_download()
 * @see webform_preprocess_file_link()
 */
function webform_file_access(FileInterface $file, $operation, AccountInterface $account) {
  // Block access to temporary anonymous private file uploads.
  if ($operation == 'download' && $file->isTemporary() && $file->getOwnerId() == 0 && strpos($file->getFileUri(), 'private://webform/') === 0) {
    return AccessResult::forbidden();
  }
}

/**
 * Implements hook_file_download().
 */
function webform_file_download($uri) {
  return ManagedFile::accessFileDownload($uri);
}

/**
 * Implements hook_theme().
 */
function webform_theme() {
  $info = [
    'webform_help' => [
      'variables' => ['info' => []],
    ],
    'webform_help_video_youtube' => [
      'variables' => ['youtube_id' => NULL],
    ],

    'webform' => [
      'render element' => 'element',
    ],
    'webform_actions' => [
      'render element' => 'element',
    ],
    'webform_handler_email_summary' => [
      'variables' => ['settings' => NULL, 'handler' => []],
    ],
    'webform_handler_remote_post_summary' => [
      'variables' => ['settings' => NULL, 'handler' => []],
    ],

    'webform_confirmation' => [
      'variables' => ['webform' => NULL, 'source_entity' => NULL, 'webform_submission' => NULL],
    ],

    'webform_submission_navigation' => [
      'variables' => ['webform_submission' => NULL],
    ],
    'webform_submission_information' => [
      'variables' => ['webform_submission' => NULL, 'source_entity' => NULL, 'open' => FALSE],
    ],

    'webform_submission_html' => [
      'variables' => ['webform_submission' => NULL, 'source_entity' => NULL],
    ],
    'webform_submission_table' => [
      'variables' => ['webform_submission' => NULL, 'source_entity' => NULL],
    ],
    'webform_submission_text' => [
      'variables' => ['webform_submission' => NULL, 'source_entity' => NULL],
    ],
    'webform_submission_yaml' => [
      'variables' => ['webform_submission' => NULL, 'source_entity' => NULL],
    ],

    'webform_element_base_html' => [
      'variables' => ['element' => [], 'value' => NULL, 'options' => []],
    ],
    'webform_element_base_text' => [
      'variables' => ['element' => [], 'value' => NULL, 'options' => []],
    ],

    'webform_container_base_html' => [
      'variables' => ['element' => [], 'value' => NULL, 'options' => []],
    ],
    'webform_container_base_text' => [
      'variables' => ['element' => [], 'value' => NULL, 'options' => []],
    ],

    'webform_element_color_value_swatch' => [
      'variables' => ['element' => NULL, 'value' => NULL, 'options' => []],
    ],

    'webform_element_managed_file' => [
      'variables' => ['element' => NULL, 'value' => NULL, 'options' => [], 'file' => NULL],
    ],
    'webform_element_audio_file' => [
      'variables' => ['element' => NULL, 'value' => NULL, 'options' => [], 'file' => NULL],
    ],
    'webform_element_document_file' => [
      'variables' => ['element' => NULL, 'value' => NULL, 'options' => [], 'file' => NULL],
    ],
    'webform_element_image_file' => [
      'variables' => ['element' => NULL, 'value' => NULL, 'options' => [], 'file' => NULL],
    ],
    'webform_element_video_file' => [
      'variables' => ['element' => NULL, 'value' => NULL, 'options' => [], 'file' => NULL],
    ],

    'webform_message' => [
      'render element' => 'element',
    ],
    'webform_composite_address' => [
      'render element' => 'element',
    ],
    'webform_composite_contact' => [
      'render element' => 'element',
    ],
    'webform_composite_creditcard' => [
      'render element' => 'element',
    ],
    'webform_composite_location' => [
      'render element' => 'element',
    ],
    'webform_composite_name' => [
      'render element' => 'element',
    ],
    'webform_composite_telephone' => [
      'render element' => 'element',
    ],

    'webform_codemirror' => [
      'variables' => ['code' => NULL, 'type' => 'text'],
    ],

    'webform_progress' => [
      'variables' => [
        'webform' => NULL,
        'current_page' => NULL,
      ],
    ],

    'webform_progress_bar' => [
      'variables' => [
        'webform' => NULL,
        'current_page' => NULL,
        'max_pages' => 10,
      ],
    ],
  ];

  // Since any rendering of a webform is going to require 'webform.theme.inc'
  // we are going to just add it to every template.
  foreach ($info as &$template) {
    $template['file'] = 'includes/webform.theme.inc';
  }

  return $info;
}

/**
 * Implements hook_theme_registry_alter().
 */
function webform_theme_registry_alter(&$theme_registry) {
  // Allow attributes to be defined for status messages so that #states
  // can be added to messages.
  // @see \Drupal\webform\Element\WebformMessage
  if (!isset($theme_registry['status_messages']['variables']['attributes'])) {
    $theme_registry['status_messages']['variables']['attributes'] = [];
  }
}

/**
 * Implements hook_theme_suggestions_alter().
 */
function webform_theme_suggestions_alter(array &$suggestions, array $variables, $hook) {
  if (strpos($hook, 'webform') !== 0) {
    return;
  }

  if ($hook == 'webform') {
    $suggestions[] = $hook . '__' . $variables['element']['#webform_id'];
  }
  elseif (strpos($hook, 'webform_element_base_') === 0 || strpos($hook, 'webform_container_base_') === 0) {
    $element = $variables['element'];

    if (empty($element['#type'])) {
      return;
    }

    $type = $element['#type'];
    $name = $element['#webform_key'];

    $suggestions[] = $hook . '__' . $type;
    $suggestions[] = $hook . '__' . $type . '__' . $name;
  }
  elseif (isset($variables['webform_submission'])) {
    /** @var \Drupal\webform\WebformSubmissionInterface $webform_submission */
    $webform_submission = $variables['webform_submission'];
    $webform = $webform_submission->getWebform();
    $suggestions[] = $hook . '__' . $webform->id();
  }
  elseif (isset($variables['webform'])) {
    /** @var \Drupal\webform\WebformInterface $webform */
    $webform = $variables['webform'];
    $suggestions[] = $hook . '__' . $webform->id();
  }
}
/**
 * Prepares variables for checkboxes templates.
 *
 * @see \Drupal\webform\Plugin\WebformElement\OptionsBase
 */
function webform_preprocess_checkboxes(&$variables) {
  $element = $variables['element'];
  $options_display = (!empty($element['#options_display'])) ? $element['#options_display'] : 'one_column';
  $variables['attributes']['class'][] = 'webform-options-display-' . str_replace('_', '-', $options_display);
  $variables['#attached']['library'][] = 'webform/webform.element.options';
}

/**
 * Prepares variables for radios templates.
 *
 * @see \Drupal\webform\Plugin\WebformElement\OptionsBase
 */
function webform_preprocess_radios(&$variables) {
  webform_preprocess_checkboxes($variables);
  // @see js/webform.element.radios.js
  $variables['attributes']['class'][] = 'js-webform-radios';
}

/**
 * Prepares variables for file link templates.
 *
 * @see webform_file_access
 */
function webform_preprocess_file_link(&$variables) {
  /** @var \Drupal\file\FileInterface $file */
  $file = $variables['file'];
  $file = ($file instanceof File) ? $file : File::load($file->fid);

  // Remove link to temporary anonymous private file uploads.
  if ($file->isTemporary() && $file->getOwnerId() === 0 && strpos($file->getFileUri(), 'private://webform/') === 0) {
    $variables['link'] = $file->getFilename();
  }
}

/**
 * Adds JavaScript to change the state of an element based on another element.
 *
 * @param array $elements
 *   A renderable array element having a #states property as described above.
 * @param string $key
 *   The element property to add the states attribute to.
 *
 * @see drupal_process_states()
 */
function webform_process_states(array &$elements, $key = '#attributes') {
  if (empty($elements['#states'])) {
    return;
  }

  $elements['#attached']['library'][] = 'core/drupal.states';
  $elements[$key]['data-drupal-states'] = Json::encode($elements['#states']);
  // Make sure to include target class for this container.
  if (empty($elements[$key]['class']) || !WebformArrayHelper::inArray(['js-form-item', 'js-form-submit', 'js-form-wrapper'], $elements[$key]['class'])) {
    $elements[$key]['class'][] = 'js-form-item';
  }
}

/******************************************************************************/
// Private functions.
/******************************************************************************/

/**
 * Provides custom PHP error handling when webform rendering is validated.
 *
 * Converts E_RECOVERABLE_ERROR to WARNING so that an exceptions can be thrown
 * and caught by
 * \Drupal\webform\WebformEntityElementsValidator::validateRendering().
 *
 * @param int $error_level
 *   The level of the error raised.
 * @param string $message
 *   The error message.
 * @param string $filename
 *   The filename that the error was raised in.
 * @param int $line
 *   The line number the error was raised at.
 * @param array $context
 *   An array that points to the active symbol table at the point the error
 *   occurred.
 *
 * @throws \ErrorException
 *   Throw ErrorException for E_RECOVERABLE_ERROR errors.
 *
 * @see \Drupal\webform\WebformEntityElementsValidator::validateRendering()
 */
function _webform_entity_element_validate_rendering_error_handler($error_level, $message, $filename, $line, array $context) {
  // From: http://stackoverflow.com/questions/15461611/php-try-catch-not-catching-all-exceptions
  if (E_RECOVERABLE_ERROR === $error_level) {
    // Allow Drupal to still log the error but convert it to a warning.
    _drupal_error_handler(E_WARNING, $message, $filename, $line, $context);
    throw new ErrorException($message, $error_level, 0, $filename, $line);
  }
  else {
    _drupal_error_handler($message, $message, $filename, $line, $context);
  }
}

/**
 * Implements hook_query_alter().
 *
 * Append EAV sort to webform_submission entity query.
 *
 * @see http://stackoverflow.com/questions/12893314/sorting-eav-database
 * @see \Drupal\webform\WebformSubmissionListBuilder::getEntityIds
 */
function webform_query_alter(AlterableInterface $query) {
  /** @var \Drupal\Core\Database\Query\SelectInterface $query */
  $name = $query->getMetaData('webform_submission_element_name');
  if (!$name) {
    return;
  }

  $direction = $query->getMetaData('webform_submission_element_direction');
  $property_name = $query->getMetaData('webform_submission_element_property_name');

  $query->distinct();
  $query->addJoin('INNER', 'webform_submission_data', NULL, 'base_table.sid = webform_submission_data.sid');
  $query->addField('webform_submission_data', 'value', 'value');
  $query->condition('name', $name);
  if ($property_name) {
    $query->condition('property', $property_name);
  }
  $query->orderBy('value', $direction);
}