class Term

class Term extends EditorialContentEntityBase implements TermInterface {
  
  /**
   * {@inheritdoc}
   */
  public static function postDelete(EntityStorageInterface $storage, array $entities) {
    parent::postDelete($storage, $entities);
    // See if any of the term's children are about to be become orphans.
    $orphans = [];
    /** @var \Drupal\taxonomy\TermInterface $term */
    foreach ($entities as $tid => $term) {
      if ($children = $storage->getChildren($term)) {
        /** @var \Drupal\taxonomy\TermInterface $child */
        foreach ($children as $child) {
          $parent = $child->get('parent');
          // Update child parents item list.
          $parent->filter(function ($item) use ($tid) {
            return $item->target_id != $tid;
          });
          // If the term has multiple parents, we don't delete it.
          if ($parent->count()) {
            $child->save();
          }
          else {
            $orphans[] = $child;
          }
        }
      }
    }
    if (!empty($orphans)) {
      $storage->delete($orphans);
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function preSave(EntityStorageInterface $storage) {
    parent::preSave($storage);
    // Terms with no parents are mandatory children of <root>.
    if (!$this->get('parent')
      ->count()) {
      $this->parent->target_id = 0;
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
    /** @var \Drupal\Core\Field\BaseFieldDefinition[] $fields */
    $fields = parent::baseFieldDefinitions($entity_type);
    // @todo Remove the usage of StatusItem in
    //   https://www.drupal.org/project/drupal/issues/2936864.
    $fields['status']->getItemDefinition()
      ->setClass(StatusItem::class);
    $fields['tid']->setLabel(t('Term ID'))
      ->setDescription(t('The term ID.'));
    $fields['uuid']->setDescription(t('The term UUID.'));
    $fields['status']->setDisplayOptions('form', [
      'type' => 'boolean_checkbox',
      'settings' => [
        'display_label' => TRUE,
      ],
      'weight' => 100,
    ])
      ->setDisplayConfigurable('form', TRUE);
    $fields['vid']->setLabel(t('Vocabulary'))
      ->setDescription(t('The vocabulary to which the term is assigned.'));
    $fields['langcode']->setDescription(t('The term language code.'));
    $fields['name'] = BaseFieldDefinition::create('string')->setLabel(t('Name'))
      ->setTranslatable(TRUE)
      ->setRevisionable(TRUE)
      ->setRequired(TRUE)
      ->setSetting('max_length', 255)
      ->setDisplayOptions('view', [
      'label' => 'hidden',
      'type' => 'string',
      'weight' => -5,
    ])
      ->setDisplayOptions('form', [
      'type' => 'string_textfield',
      'weight' => -5,
    ])
      ->setDisplayConfigurable('form', TRUE);
    $fields['description'] = BaseFieldDefinition::create('text_long')->setLabel(t('Description'))
      ->setTranslatable(TRUE)
      ->setRevisionable(TRUE)
      ->setDisplayOptions('view', [
      'label' => 'hidden',
      'type' => 'text_default',
      'weight' => 0,
    ])
      ->setDisplayConfigurable('view', TRUE)
      ->setDisplayOptions('form', [
      'type' => 'text_textfield',
      'weight' => 0,
    ])
      ->setDisplayConfigurable('form', TRUE);
    $fields['weight'] = BaseFieldDefinition::create('integer')->setLabel(t('Weight'))
      ->setDescription(t('The weight of this term in relation to other terms.'))
      ->setDefaultValue(0);
    $fields['parent'] = BaseFieldDefinition::create('entity_reference')->setLabel(t('Term Parents'))
      ->setDescription(t('The parents of this term.'))
      ->setSetting('target_type', 'taxonomy_term')
      ->setCardinality(BaseFieldDefinition::CARDINALITY_UNLIMITED);
    $fields['changed'] = BaseFieldDefinition::create('changed')->setLabel(t('Changed'))
      ->setDescription(t('The time that the term was last edited.'))
      ->setTranslatable(TRUE)
      ->setRevisionable(TRUE);
    // @todo Keep this field hidden until we have a revision UI for terms.
    // @see https://www.drupal.org/project/drupal/issues/2936995
    $fields['revision_log_message']->setDisplayOptions('form', [
      'region' => 'hidden',
    ]);
    return $fields;
  }
  
  /**
   * {@inheritdoc}
   */
  public static function bundleFieldDefinitions(EntityTypeInterface $entity_type, $bundle, array $base_field_definitions) {
    // Only terms in the same bundle can be a parent.
    $fields['parent'] = clone $base_field_definitions['parent'];
    $fields['parent']->setSetting('handler_settings', [
      'target_bundles' => [
        $bundle => $bundle,
      ],
    ]);
    return $fields;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getDescription() {
    return $this->get('description')->value;
  }
  
  /**
   * {@inheritdoc}
   */
  public function setDescription($description) {
    $this->set('description', $description);
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getFormat() {
    return $this->get('description')->format;
  }
  
  /**
   * {@inheritdoc}
   */
  public function setFormat($format) {
    $this->get('description')->format = $format;
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getName() {
    return $this->label();
  }
  
  /**
   * {@inheritdoc}
   */
  public function setName($name) {
    $this->set('name', $name);
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getWeight() {
    return (int) $this->get('weight')->value;
  }
  
  /**
   * {@inheritdoc}
   */
  public function setWeight($weight) {
    $this->set('weight', $weight);
    return $this;
  }

}