class BlockContentHooks

class BlockContentHooks {
  use StringTranslationTrait;
  
  /**
   * Implements hook_help().
   */
  public function help($route_name, RouteMatchInterface $route_match) : ?string {
    switch ($route_name) {
      case 'help.page.block_content':
        $field_ui = \Drupal::moduleHandler()->moduleExists('field_ui') ? Url::fromRoute('help.page', [
          'name' => 'field_ui',
        ])->toString() : '#';
        $output = '';
        $output .= '<h2>' . $this->t('About') . '</h2>';
        $output .= '<p>' . $this->t('The Block Content module allows you to create and manage custom <em>block types</em> and <em>content-containing blocks</em>. For more information, see the <a href=":online-help">online documentation for the Block Content module</a>.', [
          ':online-help' => 'https://www.drupal.org/documentation/modules/block_content',
        ]) . '</p>';
        $output .= '<h2>' . $this->t('Uses') . '</h2>';
        $output .= '<dl>';
        $output .= '<dt>' . $this->t('Creating and managing block types') . '</dt>';
        $output .= '<dd>' . $this->t('Users with the <em>Administer blocks</em> permission can create and edit block types with fields and display settings, from the <a href=":types">Block types</a> page under the Structure menu. For more information about managing fields and display settings, see the <a href=":field-ui">Field UI module help</a> and <a href=":field">Field module help</a>.', [
          ':types' => Url::fromRoute('entity.block_content_type.collection')->toString(),
          ':field-ui' => $field_ui,
          ':field' => Url::fromRoute('help.page', [
            'name' => 'field',
          ])->toString(),
        ]) . '</dd>';
        $output .= '<dt>' . $this->t('Creating content blocks') . '</dt>';
        $output .= '<dd>' . $this->t('Users with the <em>Administer blocks</em> permission can create, edit, and delete content blocks of each defined block type, from the <a href=":block-library">Content blocks page</a>. After creating a block, place it in a region from the <a href=":blocks">Block layout page</a>, just like blocks provided by other modules.', [
          ':blocks' => Url::fromRoute('block.admin_display')->toString(),
          ':block-library' => Url::fromRoute('entity.block_content.collection')->toString(),
        ]) . '</dd>';
        $output .= '</dl>';
        return $output;
    }
    return NULL;
  }
  
  /**
   * Implements hook_theme().
   */
  public function theme($existing, $type, $theme, $path) : array {
    return [
      'block_content_add_list' => [
        'variables' => [
          'content' => NULL,
        ],
        'file' => 'block_content.pages.inc',
      ],
    ];
  }
  
  /**
   * Implements hook_entity_type_alter().
   */
  public function entityTypeAlter(array &$entity_types) : void {
    /** @var \Drupal\Core\Entity\EntityTypeInterface[] $entity_types */
    // Add a translation handler for fields if the language module is enabled.
    if (\Drupal::moduleHandler()->moduleExists('language')) {
      $translation = $entity_types['block_content']->get('translation');
      $translation['block_content'] = TRUE;
      $entity_types['block_content']->set('translation', $translation);
    }
    // Swap out the default EntityChanged constraint with a custom one with
    // different logic for inline blocks.
    $constraints = $entity_types['block_content']->getConstraints();
    unset($constraints['EntityChanged']);
    $constraints['BlockContentEntityChanged'] = NULL;
    $entity_types['block_content']->setConstraints($constraints);
  }
  
  /**
   * Implements hook_query_TAG_alter().
   *
   * Alters any 'entity_reference' query where the entity type is
   * 'block_content' and the query has the tag 'block_content_access'.
   *
   * These queries should only return reusable blocks unless a condition on
   * 'reusable' is explicitly set.
   *
   * Block_content entities that are not reusable should by default not be
   * selectable as entity reference values. A module can still create an
   * instance of \Drupal\Core\Entity\EntityReferenceSelection\SelectionInterface
   * that will allow selection of non-reusable blocks by explicitly setting a
   * condition on the 'reusable' field.
   *
   * @see \Drupal\block_content\BlockContentAccessControlHandler
   */
  public function queryEntityReferenceAlter(AlterableInterface $query) : void {
    if ($query instanceof SelectInterface && $query->getMetaData('entity_type') === 'block_content' && $query->hasTag('block_content_access')) {
      $data_table = \Drupal::entityTypeManager()->getDefinition('block_content')
        ->getDataTable();
      if (array_key_exists($data_table, $query->getTables()) && !_block_content_has_reusable_condition($query->conditions(), $query->getTables())) {
        $query->condition("{$data_table}.reusable", TRUE);
      }
    }
  }
  
  /**
   * Implements hook_theme_suggestions_HOOK_alter() for block templates.
   */
  public function themeSuggestionsBlockAlter(array &$suggestions, array $variables) : void {
    $suggestions_new = [];
    $content = $variables['elements']['content'];
    $block_content = $variables['elements']['content']['#block_content'] ?? NULL;
    if ($block_content instanceof BlockContentInterface) {
      $bundle = $content['#block_content']->bundle();
      $view_mode = strtr($variables['elements']['content']['#view_mode'], '.', '_');
      $suggestions_new[] = 'block__block_content__view__' . $view_mode;
      $suggestions_new[] = 'block__block_content__type__' . $bundle;
      $suggestions_new[] = 'block__block_content__view_type__' . $bundle . '__' . $view_mode;
      if (!empty($variables['elements']['#id'])) {
        $suggestions_new[] = 'block__block_content__id__' . $variables['elements']['#id'];
        $suggestions_new[] = 'block__block_content__id_view__' . $variables['elements']['#id'] . '__' . $view_mode;
      }
      // Remove duplicate block__block_content.
      $suggestions = array_unique($suggestions);
      array_splice($suggestions, 1, 0, $suggestions_new);
    }
  }
  
  /**
   * Implements hook_entity_operation().
   */
  public function entityOperation(EntityInterface $entity) : array {
    $operations = [];
    if ($entity instanceof BlockInterface) {
      $plugin = $entity->getPlugin();
      if ($plugin->getBaseId() === 'block_content') {
        $custom_block = \Drupal::entityTypeManager()->getStorage('block_content')
          ->loadByProperties([
          'uuid' => $plugin->getDerivativeId(),
        ]);
        $custom_block = reset($custom_block);
        if ($custom_block && $custom_block->access('update')) {
          $operations['block-edit'] = [
            'title' => $this->t('Edit block'),
            'url' => $custom_block->toUrl('edit-form')
              ->setOptions([]),
            'weight' => 50,
          ];
        }
      }
    }
    return $operations;
  }

}