islandora/islandora.module

<?php

/**
 * @file
 * Contains islandora.module.
 *
 * This file is part of the Islandora Project.
 *
 * (c) Islandora Foundation
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 *
 * @author Diego Pino Navarro <dpino@metro.org> https://github.com/diegopino
 */

use Drupal\Component\Plugin\Exception\PluginNotFoundException;
use Drupal\Core\Entity\Display\EntityViewDisplayInterface;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Site\Settings;
use Drupal\Core\Url;
use Drupal\islandora\Form\IslandoraSettingsForm;
use Drupal\node\NodeInterface;
use Drupal\media\MediaInterface;
use Drupal\file\FileInterface;
use Drupal\taxonomy\TermInterface;
use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\serialization\Normalizer\CacheableNormalizerInterface;
use Drupal\Core\Entity\EntityForm;
use Drupal\file\Entity\File;

/**
 * Implements hook_help().
 */
function islandora_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    // Main module help for the islandora module.
    case 'help.page.islandora':
      $output = '';
      $output .= '<h3>' . t('About') . '</h3>';
      $output .= '<p>' . t('Islandora integrates Drupal with a Fedora repository.') . '</p>';
      return $output;

    default:
  }
}

/**
 * Implements hook_node_insert().
 */
function islandora_node_insert(NodeInterface $node) {
  $utils = \Drupal::service('islandora.utils');

  // Execute index reactions.
  $utils->executeNodeReactions('\Drupal\islandora\Plugin\ContextReaction\IndexReaction', $node);
}

/**
 * Implements hook_node_update().
 */
function islandora_node_update(NodeInterface $node) {

  $utils = \Drupal::service('islandora.utils');
  if (!$utils->haveFieldsChanged($node, $node->original)) {
    return;
  };

  // Execute index reactions.
  $utils->executeNodeReactions('\Drupal\islandora\Plugin\ContextReaction\IndexReaction', $node);
}

/**
 * Implements hook_node_delete().
 */
function islandora_node_delete(NodeInterface $node) {
  $utils = \Drupal::service('islandora.utils');

  // Execute delete reactions.
  $utils->executeNodeReactions('\Drupal\islandora\Plugin\ContextReaction\DeleteReaction', $node);
}

/**
 * Implements hook_media_insert().
 */
function islandora_media_insert(MediaInterface $media) {
  $utils = \Drupal::service('islandora.utils');
  // Execute index reactions.
  $utils->executeMediaReactions('\Drupal\islandora\Plugin\ContextReaction\IndexReaction', $media);

  // If it has a parent node...
  $node = $utils->getParentNode($media);
  if ($node) {
    // Fire off derivative reactions for the Media.
    $utils->executeDerivativeReactions(
      '\Drupal\islandora\Plugin\ContextReaction\DerivativeReaction',
      $node,
      $media
    );
  }
  // Wait until the media insert is complete, then fire file derivatives.
  drupal_register_shutdown_function('_islandora_fire_media_file_derivative_reaction', $media);
}

/**
 * Implements hook_media_update().
 */
function islandora_media_update(MediaInterface $media) {
  $media_source_service = \Drupal::service('islandora.media_source_service');

  // Exit early if nothing's changed.
  $utils = \Drupal::service('islandora.utils');
  if (!$utils->haveFieldsChanged($media, $media->original)) {
    return;
  };

  // Execute index reactions.
  $utils->executeMediaReactions('\Drupal\islandora\Plugin\ContextReaction\IndexReaction', $media);
  // Does it have a source field?
  $source_field = $media_source_service->getSourceFieldName($media->bundle());
  if (empty($source_field)) {
    return;
  }

  // Exit early if the source file did not change.
  if ($media->get($source_field)->equals($media->original->get($source_field))) {
    return;
  }
  // If it has a parent node...
  $node = $utils->getParentNode($media);
  if ($node) {
    // Fire off derivative reactions for the Media.
    $utils->executeDerivativeReactions(
      '\Drupal\islandora\Plugin\ContextReaction\DerivativeReaction',
      $node,
      $media
    );
    $utils->executeMediaReactions('\Drupal\islandora\Plugin\ContextReaction\DerivativeFileReaction', $media);
  }
}

/**
 * Implements hook_media_delete().
 */
function islandora_media_delete(MediaInterface $media) {
  $utils = \Drupal::service('islandora.utils');

  // Execute delete reactions.
  $utils->executeMediaReactions('\Drupal\islandora\Plugin\ContextReaction\DeleteReaction', $media);
}

/**
 * Helper to fire media derivative file reactions after a media 'insert'.
 *
 * This function should not be called on its own; it exists as a workaround to
 * being unable to fire media events after a media insert operation. This
 * behaviour will eventually be replaced by event listeners once these are
 * implemented in Drupal 9.
 *
 * @param \Drupal\Core\Media\MediaInterface $media
 *   The media that was just inserted.
 *
 * @see https://www.drupal.org/project/drupal/issues/2551893
 */
function _islandora_fire_media_file_derivative_reaction(MediaInterface $media) {
  $utils = \Drupal::service('islandora.utils');
  // Execute derivative file reactions.
  $utils->executeMediaReactions('\Drupal\islandora\Plugin\ContextReaction\DerivativeFileReaction', $media);
}

/**
 * Implements hook_file_insert().
 */
function islandora_file_insert(FileInterface $file) {
  $utils = \Drupal::service('islandora.utils');

  // Execute index reactions.
  $utils->executeFileReactions('\Drupal\islandora\Plugin\ContextReaction\IndexReaction', $file);
}

/**
 * Implements hook_file_update().
 */
function islandora_file_update(FileInterface $file) {
  // Exit early if unchanged.
  if ($file->hasField('sha1') && $file->original->hasField('sha1')
    && $file->sha1->getString() == $file->original->sha1->getString()) {
    return;
  }

  $utils = \Drupal::service('islandora.utils');

  // Execute index reactions.
  $utils->executeFileReactions('\Drupal\islandora\Plugin\ContextReaction\IndexReaction', $file);

  // Execute derivative reactions.
  foreach ($utils->getReferencingMedia($file->id()) as $media) {
    $node = $utils->getParentNode($media);
    if ($node) {
      $utils->executeDerivativeReactions(
        '\Drupal\islandora\Plugin\ContextReaction\DerivativeReaction',
        $node,
        $media
      );
    }
  }
}

/**
 * Implements hook_file_delete().
 */
function islandora_file_delete(FileInterface $file) {
  $utils = \Drupal::service('islandora.utils');

  // Execute delete reactions.
  $utils->executeFileReactions('\Drupal\islandora\Plugin\ContextReaction\DeleteReaction', $file);
}

/**
 * Implements hook_taxonomy_term_insert().
 */
function islandora_taxonomy_term_insert(TermInterface $term) {
  $utils = \Drupal::service('islandora.utils');

  // Execute index reactions.
  $utils->executeTermReactions('\Drupal\islandora\Plugin\ContextReaction\IndexReaction', $term);
}

/**
 * Implements hook_taxonomy_term_update().
 */
function islandora_taxonomy_term_update(TermInterface $term) {
  $utils = \Drupal::service('islandora.utils');

  // Execute index reactions.
  $utils->executeTermReactions('\Drupal\islandora\Plugin\ContextReaction\IndexReaction', $term);
}

/**
 * Implements hook_taxonomy_term_delete().
 */
function islandora_taxonomy_term_delete(TermInterface $term) {
  $utils = \Drupal::service('islandora.utils');

  // Execute delete reactions.
  $utils->executeTermReactions('\Drupal\islandora\Plugin\ContextReaction\DeleteReaction', $term);
}

/**
 * Implements hook_jsonld_alter_normalized_array().
 */
function islandora_jsonld_alter_normalized_array(EntityInterface $entity, array &$normalized, array $context) {
  $context_manager = \Drupal::service('context.manager');
  foreach ($context_manager->getActiveReactions('\Drupal\islandora\ContextReaction\NormalizerAlterReaction') as $reaction) {
    $reaction->execute($entity, $normalized, $context);
    foreach ($context_manager->getActiveContexts() as $context_config) {
      try {
        if ($context_config->getReaction($reaction->getPluginId()) && isset($context[CacheableNormalizerInterface::SERIALIZATION_CONTEXT_CACHEABILITY])) {
          $context[CacheableNormalizerInterface::SERIALIZATION_CONTEXT_CACHEABILITY]->addCacheableDependency($context_config);
        };
      }
      catch (PluginNotFoundException $e) {
        // Squash :(.
      }
    }
  }
}

/**
 * Implements hook_entity_view_mode_alter().
 */
function islandora_entity_view_mode_alter(&$view_mode, EntityInterface $entity) {
  // Change the view mode based on user input from a 'view_mode_alter'
  // ContextReaction.
  $entity_type = $entity->getEntityType()->id();
  $storage = \Drupal::service('entity_type.manager')->getStorage('entity_view_mode');
  $context_manager = \Drupal::service('context.manager');
  $current_entity = \Drupal::routeMatch()->getParameter($entity_type);
  $current_id = ($current_entity instanceof NodeInterface || $current_entity instanceof MediaInterface) ? $current_entity->id() : NULL;
  if (isset($current_id) && $current_id == $entity->id()) {
    foreach ($context_manager->getActiveReactions('\Drupal\islandora\Plugin\ContextReaction\ViewModeAlterReaction') as $reaction) {
      // Construct the new view mode's machine name.
      $entity_type = $entity->getEntityTypeId();
      $mode = $reaction->execute();
      $machine_name = "$entity_type.$mode";

      // Try to load it.
      $new_mode = $storage->load($machine_name);

      // If successful, alter the view mode.
      if ($new_mode) {
        $view_mode = $mode;
      }
      else {
        // Otherwise, leave it be, but log a message.
        \Drupal::logger('islandora')
          ->info("EntityViewMode $machine_name does not exist.  View mode cannot be altered.");
      }
    }
  }
}

/**
 * Implements hook_preprocess_node().
 */
function islandora_preprocess_node(&$variables) {
  // Using alternate view modes causes on a node's canoncial page
  // causes the title to get printed out twice.  Once from the
  // fields themselves and again as a block above the main content.
  // Setting 'page' to TRUE gets rid of the title in the fields and
  // leaves the block.  This makes it look uniform with the 'default'
  // view mode.
  if (node_is_page($variables['elements']['#node'])) {
    $variables['page'] = TRUE;
  }
}

/**
 * Implements hook_form_alter().
 */
function islandora_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  $media_add_forms = ['media_audio_add_form', 'media_document_add_form',
    'media_extracted_text_add_form', 'media_file_add_form', 'media_image_add_form',
    'media_fits_technical_metadata_add_form', 'media_video_add_form',
  ];

  if (in_array($form['#form_id'], $media_add_forms)) {
    $params = \Drupal::request()->query->all();
    if (isset($params['edit'])) {
      $media_of_nid = $params['edit']['field_media_of']['widget'][0]['target_id'];
      $node = \Drupal::entityTypeManager()->getStorage('node')->load($media_of_nid);
      if ($node) {
        $form['name']['widget'][0]['value']['#default_value'] = $node->getTitle();
      }
      $form['actions']['submit']['#submit'][] = 'islandora_media_custom_form_submit';
    }
  }

  $form_object = $form_state->getFormObject();
  $utils = \Drupal::service('islandora.utils');
  $config = \Drupal::config('islandora.settings')->get('delete_media_and_files');

  if ($config == 1 && $form_object instanceof EntityForm) {
    $entity = $form_object->getEntity();

    if ($entity->getEntityTypeId() == "node" && $utils->isIslandoraType($entity->getEntityTypeId(), $entity->bundle()) && strpos($form['#form_id'], 'delete_form') !== FALSE) {
      $medias = $utils->getMedia($form_state->getFormObject()->getEntity());
      if (count($medias) != 0) {
        $form['delete_associated_content'] = [
          '#type' => 'checkbox',
          '#title' => t('Delete all associated medias and nodes'),
        ];

        $media_list = [];

        foreach ($medias as $media) {
          $media_list[] = $media->getName();
        }

        $form['container'] = [
          '#type' => 'container',
          '#states' => [
            'visible' => [
              ':input[name="delete_associated_content"]' => ['checked' => TRUE],
            ],
          ],
        ];

        $form['container']['media_items'] = [
          '#theme' => 'item_list',
          '#type' => 'ul',
          '#items' => $media_list,
          '#attributes' => ['class' => ['islandora-media-items']],
          '#wrapper_attributes' => ['class' => ['container']],
          '#attached' => [
            'library' => [
              'islandora/islandora',
            ],
          ],
        ];

        $form['actions']['submit']['#submit'][] = 'islandora_object_delete_form_submit';
        return $form;
      }
    }
  }

  return $form;
}

/**
 * Redirect submit handler for media save.
 */
function islandora_media_custom_form_submit(&$form, FormStateInterface $form_state) {
  // Check configuration to see whether a redirect is desired.
  $redirect = \Drupal::config('islandora.settings')->get('redirect_after_media_save');
  if ($redirect) {
    $params = \Drupal::request()->query->all();
    if (!empty($params)) {
      $target_id = $params['edit']['field_media_of']['widget'][0]['target_id'];
      $url = Url::fromRoute('view.media_of.page_1', ['node' => $target_id]);
      $form_state->setRedirectUrl($url);
    }
  }
}

/**
 * Implements a submit handler for the delete form.
 */
function islandora_object_delete_form_submit($form, FormStateInterface $form_state) {

  $result = $form_state->getValues('delete_associated_content');
  $utils = \Drupal::service('islandora.utils');

  if ($result['delete_associated_content'] == 1) {

    $node = $form_state->getFormObject()->getEntity();
    $medias = $utils->getMedia($node);
    $media_list = [];

    $entity_field_manager = \Drupal::service('entity_field.manager');
    $current_user = \Drupal::currentUser();
    $logger = \Drupal::logger('logger.channel.islandora');
    $messenger = \Drupal::messenger();

    $delete_media = [];
    $media_translations = [];
    $media_files = [];
    $entity_protected_medias = [];
    $inaccessible_entities = [];

    foreach ($medias as $id => $media) {
      $lang = $media->language()->getId();
      $selected_langcodes[$lang] = $lang;

      if (!$media->access('delete', $current_user)) {
        $inaccessible_entities[] = $media;
        continue;
      }
      // Check for files.
      $fields = $entity_field_manager->getFieldDefinitions('media', $media->bundle());
      foreach ($fields as $field) {
        $type = $field->getType();
        if ($type == 'file' || $type == 'image') {
          $target_id = $media->get($field->getName())->target_id;
          $file = File::load($target_id);
          if ($file) {
            if (!$file->access('delete', $current_user)) {
              $inaccessible_entities[] = $file;
              continue;
            }
            $media_files[$id][$file->id()] = $file;
          }
        }
      }

      foreach ($selected_langcodes as $langcode) {
        // We're only working with media, which are translatable.
        $entity = $media->getTranslation($langcode);
        if ($entity->isDefaultTranslation()) {
          $delete_media[$id] = $entity;
          unset($media_translations[$id]);
        }
        elseif (!isset($delete_media[$id])) {
          $media_translations[$id][] = $entity;
        }
      }
    }

    if ($delete_media) {
      foreach ($delete_media as $id => $media) {
        try {
          $media->delete();
          $media_list[] = $id;
          $logger->notice('The media %label has been deleted.', [
            '%label' => $media->label(),
          ]);
        }
        catch (Exception $e) {
          $entity_protected_medias[] = $id;
        }
      }
    }

    $delete_files = array_filter($media_files, function ($media) use ($entity_protected_medias) {
      return !in_array($media, $entity_protected_medias);
    }, ARRAY_FILTER_USE_KEY);

    if ($delete_files) {
      foreach ($delete_files as $files_array) {
        foreach ($files_array as $file) {
          $file->delete();
          $logger->notice('The file %label has been deleted.', [
            '%label' => $file->label(),
          ]);
        }
      }
    }

    $delete_media_translations = array_filter($media_translations, function ($media) use ($entity_protected_medias) {
      return !in_array($media, $entity_protected_medias);
    }, ARRAY_FILTER_USE_KEY);

    if ($delete_media_translations) {
      foreach ($delete_media_translations as $id => $translations) {
        $media = $medias[$id];
        foreach ($translations as $translation) {
          $media->removeTranslation($translation->language()->getId());
        }
        $media->save();
        foreach ($translations as $translation) {
          $logger->notice('The media %label @language translation has been deleted', [
            '%label' => $media->label(),
            '@language' => $translation->language()->getName(),
          ]);
        }
      }
    }

    if ($inaccessible_entities) {
      $messenger->addWarning("@count items have not been deleted because you do not have the necessary permissions.", [
        '@count' => count($inaccessible_entities),
      ]);
    }

    $build = [
      'heading' => [
        '#type' => 'html_tag',
        '#tag' => 'div',
        '#value' => t("The repository item @node and @media", [
          '@node' => $node->getTitle(),
          '@media' => \Drupal::translation()->formatPlural(
            count($media_list), 'the media with the id @media has been deleted.',
            'the medias with the ids @media have been deleted.',
            ['@media' => implode(", ", $media_list)],
          ),
        ]),
      ],
    ];

    $message = \Drupal::service('renderer')->renderPlain($build);
    $messenger->deleteByType('status');
    $messenger->addStatus($message);
  }
}

/**
 * Implements hook_field_widget_single_element_WIDGET_TYPE_form_alter().
 */
function islandora_field_widget_single_element_image_image_form_alter(&$element, $form_state, $context) {
  $element['#process'][] = 'islandora_add_default_image_alt_text';
}

/**
 * Callback for hook_field_widget_single_element_WIDGET_TYPE_form_alter().
 */
function islandora_add_default_image_alt_text($element, $form_state, $form) {
  if ($element['alt']['#access']) {
    $params = \Drupal::request()->query->all();
    if (isset($params['edit'])) {
      $media_of_nid = $params['edit']['field_media_of']['widget'][0]['target_id'];
      $node = \Drupal::entityTypeManager()->getStorage('node')->load($media_of_nid);
      if ($node) {
        $element['alt']['#default_value'] = $node->getTitle();
      }
    }
  }
  return $element;
}

/**
 * Implements hook_entity_form_display_alter().
 */
function islandora_entity_form_display_alter(&$form_display, $context) {
  // Change the form display based on user input from a 'form_display_alter'
  // ContextReaction.
  $storage = \Drupal::service('entity_type.manager')->getStorage('entity_form_display');
  $context_manager = \Drupal::service('context.manager');

  // Alter form display based on context.
  foreach ($context_manager->getActiveReactions('\Drupal\islandora\Plugin\ContextReaction\FormDisplayAlterReaction') as $reaction) {
    // Construct the new form display's machine name.
    $entity_type = $context['entity_type'];
    $bundle = $context['bundle'];
    $mode = $reaction->execute();
    $machine_name = "$entity_type.$bundle.$mode";

    // Try to load it.
    $new_display = $storage->load($machine_name);

    // If successful, alter the form display.
    if ($new_display) {
      $form_display = $new_display;
    }
    else {
      // Otherwise, leave it be, but log a message.
      \Drupal::logger('islandora')->info("EntityFormDisplay $machine_name does not exist.  Form display cannot be altered.");
    }
  }
}

/**
 * Implements hook_form_form_id_alter().
 */
function islandora_form_block_form_alter(&$form, FormStateInterface $form_state, $form_id) {
  // Unset our custom conditions.  There's too many to use well within
  // the core block placement UI, and no other reasonable way to filter
  // them out.  See https://www.drupal.org/node/2284687.  Use
  // /admin/structure/context instead if you want to use these conditions
  // to alter block layout.
  unset($form['visibility']['content_entity_type']);
  unset($form['visibility']['file_uses_filesystem']);
  unset($form['visibility']['media_has_mimetype']);
  unset($form['visibility']['media_has_term']);
  unset($form['visibility']['media_is_islandora_media']);
  unset($form['visibility']['media_uses_filesystem']);
  unset($form['visibility']['node_had_namespace']);
  unset($form['visibility']['node_has_ancestor']);
  unset($form['visibility']['node_has_parent']);
  unset($form['visibility']['node_has_term']);
  unset($form['visibility']['node_is_islandora_object']);
  unset($form['visibility']['node_referenced_by_node']);
  unset($form['visibility']['parent_node_has_term']);
}

/**
 * Implements hook_entity_extra_field_info().
 */
function islandora_entity_extra_field_info() {
  $config_factory = \Drupal::service('config.factory')->get(IslandoraSettingsForm::CONFIG_NAME);
  $extra_field = [];

  $pseudo_bundles = $config_factory->get(IslandoraSettingsForm::GEMINI_PSEUDO);

  if (!empty($pseudo_bundles)) {
    foreach ($pseudo_bundles as $key) {
      [$bundle, $content_entity] = explode(":", $key);
      $extra_field[$content_entity][$bundle]['display'][IslandoraSettingsForm::GEMINI_PSEUDO_FIELD] = [
        'label' => t('Fedora URI'),
        'description' => t('The URI to the persistent'),
        'weight' => 100,
        'visible' => TRUE,
      ];
    }
  }
  return $extra_field;
}

/**
 * Implements hook_entity_view().
 */
function islandora_entity_view(array &$build, EntityInterface $entity, EntityViewDisplayInterface $display, $view_mode) {
  $route_match_item = \Drupal::routeMatch()->getParameters()->get($entity->getEntityTypeId());
  // Ensure the entity matches the route.
  if ($entity === $route_match_item) {
    if ($display->getComponent('field_gemini_uri')) {
      $mapper = \Drupal::service('islandora.entity_mapper');
      $flysystem_config = Settings::get('flysystem');
      $fedora_root = $flysystem_config['fedora']['config']['root'];
      $fedora_root = rtrim($fedora_root, '/');

      if ($entity->getEntityTypeId() == 'media') {
        // Check if the source file is in Fedora or not.
        $media_source_service = \Drupal::service('islandora.media_source_service');
        $source_file = $media_source_service->getSourceFile($entity);
        if (!$source_file) {
          \Drupal::logger('islandora')->error(
            \Drupal::service('string_translation')->translate(
              "Can't get source file for @label (@id)", [
                '@label' => $entity->label(),
                "@id" => $entity->id(),
              ]
            )
          );
          return;
        }
        $uri = $source_file->getFileUri();
        $scheme = \Drupal::service('stream_wrapper_manager')->getScheme($uri);
        $flysystem_config = Settings::get('flysystem');

        // Use the file's path if it's in fedora.
        // Otherwise do the UUID -> pair tree thang.
        if (isset($flysystem_config[$scheme]) && $flysystem_config[$scheme]['driver'] == 'fedora') {
          $parts = parse_url($uri);
          $path = $parts['host'] . $parts['path'];
        }
        else {
          $path = $mapper->getFedoraPath($source_file->uuid());
        }
        $path = trim($path, '/');
        $fedora_uri = "$fedora_root/$path/fcr:metadata";
      }
      else {
        // All non-media entities do the UUID -> pair tree thang.
        $path = $mapper->getFedoraPath($entity->uuid());
        $path = trim($path, '/');
        $fedora_uri = "$fedora_root/$path";
      }

      // Stuff the fedora url into the pseudo field.
      $build['field_gemini_uri'] = [
        '#type' => 'container',
        '#attributes' => [
          'id' => 'field-gemini-uri',
        ],
        'internal_label' => [
          '#type' => 'item',
          '#title' => t('Fedora URI'),
          'internal_uri' => [
            '#type' => 'link',
            '#title' => t("@url", ['@url' => $fedora_uri]),
            '#url' => Url::fromUri($fedora_uri),
          ],
        ],
      ];
    }
  }
}

/**
 * Implements hook_preprocess_views_view_table().
 *
 * Used for the integer-weight drag-n-drop. Taken almost
 * verbatim from the weight module.
 */
function islandora_preprocess_views_view_table(&$variables) {

  // Check for a weight selector field.
  foreach ($variables['view']->field as $field_key => $field) {
    if ($field->getPluginId() == 'integer_weight_selector') {

      // Check if the weight selector is on the first column.
      $is_first_column = array_search($field_key, array_keys($variables['view']->field)) > 0 ? FALSE : TRUE;

      // Add the tabledrag attributes.
      foreach ($variables['rows'] as $key => $row) {
        if ($is_first_column) {
          // If the weight selector is the first column move it to the last
          // column, in order to make the draggable widget appear.
          $weight_selector = $variables['rows'][$key]['columns'][$field->field];
          unset($variables['rows'][$key]['columns'][$field->field]);
          $variables['rows'][$key]['columns'][$field->field] = $weight_selector;
        }
        // Add draggable attribute.
        $variables['rows'][$key]['attributes']->addClass('draggable');
      }
      // The row key identify in an unique way a view grouped by a field.
      // Without row number, all the groups will share the same table_id
      // and just the first table can be draggable.
      $table_id = 'weight-table-' . $variables['view']->dom_id . '-row-' . $key;
      $variables['attributes']['id'] = $table_id;

      $options = [
        'table_id' => $table_id,
        'action' => 'order',
        'relationship' => 'sibling',
        'group' => 'weight-selector',
      ];
      drupal_attach_tabledrag($variables, $options);
    }
  }
}