class HistoryCommentLinkBuilder

class HistoryCommentLinkBuilder implements CommentLinkBuilderInterface {
  use StringTranslationTrait;
  
  /**
   * Constructs a new HistoryCommentLinkBuilder object.
   */
  public function __construct(protected CommentLinkBuilderInterface $inner, protected CommentManagerInterface $commentManager, protected AccountInterface $currentUser, protected EntityTypeManagerInterface $entityTypeManager) {
  }
  
  /**
   * {@inheritdoc}
   */
  public function buildCommentedEntityLinks(FieldableEntityInterface $entity, array &$context) : array {
    $entity_links = $this->inner
      ->buildCommentedEntityLinks($entity, $context);
    if ($context['view_mode'] !== 'teaser') {
      return $entity_links;
    }
    $fields = $this->commentManager
      ->getFields($entity->getEntityTypeId());
    foreach ($fields as $field_name => $detail) {
      // Skip fields that the entity does not have.
      if (!$entity->hasField($field_name)) {
        continue;
      }
      $links = [];
      $commenting_status = $entity->get($field_name)->status;
      if ($commenting_status != CommentItemInterface::HIDDEN) {
        // Entity has commenting status open or closed.
        if ($this->currentUser
          ->hasPermission('access comments')) {
          if (!empty($entity->get($field_name)->comment_count)) {
            $links['comment-new-comments'] = [
              'title' => '',
              'url' => Url::fromRoute('<current>'),
              'attributes' => [
                'class' => 'hidden',
                'title' => new TranslatableMarkup('Jump to the first new comment.'),
                'data-history-node-last-comment-timestamp' => $entity->get($field_name)->last_comment_timestamp,
                'data-history-node-field-name' => $field_name,
              ],
            ];
          }
        }
      }
      if (!empty($links)) {
        // @todo do we have the same order as before?
        $entity_links['comment__' . $field_name]['#links'] += $links;
        if ($this->currentUser
          ->isAuthenticated()) {
          $entity_links['comment__' . $field_name]['#cache']['contexts'][] = 'user';
          $entity_links['comment__' . $field_name]['#attached']['library'][] = 'history/drupal.node-new-comments-link';
          // Embed the metadata for the "X new comments" link (if any) on this
          // entity.
          $entity_links['comment__' . $field_name]['#attached']['drupalSettings']['history']['lastReadTimestamps'][$entity->id()] = history_read($entity->id());
          $new_comments = $this->commentManager
            ->getCountNewComments($entity);
          if ($new_comments > 0) {
            $page_number = $this->entityTypeManager
              ->getStorage('comment')
              ->getNewCommentPageNumber($entity->{$field_name}->comment_count, $new_comments, $entity, $field_name);
            $query = $page_number ? [
              'page' => $page_number,
            ] : NULL;
            $value = [
              'new_comment_count' => (int) $new_comments,
              'first_new_comment_link' => $entity->toUrl('canonical', [
                'query' => $query,
                'fragment' => 'new',
              ])
                ->toString(),
            ];
            $parents = [
              'comment',
              'newCommentsLinks',
              $entity->getEntityTypeId(),
              $field_name,
              $entity->id(),
            ];
            NestedArray::setValue($entity_links['comment__' . $field_name]['#attached']['drupalSettings'], $parents, $value);
          }
        }
      }
    }
    return $entity_links;
  }

}