structural_pages/src/Plugin/ParentEntityHandler/TaxonomyTermHandler.php

<?php

declare(strict_types=1);

namespace Drupal\structural_pages\Plugin\ParentEntityHandler;

use Drupal\Core\Breadcrumb\Breadcrumb;
use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\StringTranslation\TranslatableMarkup;
use Drupal\structural_pages\Attribute\ParentEntityHandler;
use Drupal\structural_pages\ParentEntityHandler\ParentEntityHandlerBase;
use Drupal\taxonomy\TermInterface;

/**
 * Handler for taxonomy term entities.
 */
#[ParentEntityHandler(
  id: 'taxonomy_term',
  label: new TranslatableMarkup('Taxonomy Vocabularies (taxonomy_term)'),
  entity_type_id: 'taxonomy_term',
  clears_site_section: FALSE,
  sort_field: 'name',
  bundle_restrictions: [],
  weight: 0,
)]
class TaxonomyTermHandler extends ParentEntityHandlerBase {

  /**
   * {@inheritdoc}
   */
  public function getEntityFromRoute(\Drupal\Core\Routing\RouteMatchInterface $route_match): ?EntityInterface {
    $term = $route_match->getParameter('taxonomy_term');

    if (!$term instanceof TermInterface) {
      return NULL;
    }

    if (!$this->handlesEntity($term)) {
      return NULL;
    }

    return $term;
  }

  /**
   * {@inheritdoc}
   */
  public function buildBreadcrumb(Breadcrumb $breadcrumb, EntityInterface $entity): void {
    if (!$entity instanceof TermInterface) {
      return;
    }

    // Add all ancestors in the taxonomy hierarchy.
    $term_storage = $this->entityTypeManager->getStorage('taxonomy_term');
    $ancestors = $term_storage->loadAllParents($entity->id());
    $ancestors = array_reverse($ancestors);

    foreach ($ancestors as $ancestor) {
      $breadcrumb->addCacheableDependency($ancestor);
      $breadcrumb->addLink($ancestor->toLink());
    }
  }

  /**
   * {@inheritdoc}
   */
  public function handlesEntity(EntityInterface $entity): bool {
    if ($entity->getEntityTypeId() !== 'taxonomy_term') {
      return FALSE;
    }

    $vocabulary = \Drupal::config('structural_pages.settings')
      ->get('site_section_vocabulary') ?? 'site_sections';
    return $entity->bundle() === $vocabulary;
  }

  /**
   * {@inheritdoc}
   */
  public function getSiteSectionId(EntityInterface $entity): int|string|null {
    if (!$entity instanceof TermInterface) {
      return NULL;
    }

    if (!$this->handlesEntity($entity)) {
      return NULL;
    }

    return $entity->id();
  }

}