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);
        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;
    }

}