class BlockContent

class BlockContent extends EditorialContentEntityBase implements BlockContentInterface {
  use RefinableDependentAccessTrait;
  
  /**
   * The theme the block is being created in.
   *
   * When creating a new content block from the block library, the user is
   * redirected to the configure form for that block in the given theme. The
   * theme is stored against the block when the content block add form is shown.
   *
   * @var string
   */
  protected $theme;
  
  /**
   * {@inheritdoc}
   */
  public function createDuplicate() {
    $duplicate = parent::createDuplicate();
    $duplicate->revision_id->value = NULL;
    $duplicate->id->value = NULL;
    return $duplicate;
  }
  
  /**
   * {@inheritdoc}
   */
  public function setTheme($theme) {
    $this->theme = $theme;
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function getTheme() {
    return $this->theme;
  }
  
  /**
   * {@inheritdoc}
   */
  public function postSave(EntityStorageInterface $storage, $update = TRUE) {
    parent::postSave($storage, $update);
    if ($this->isReusable() || $this->getOriginal()?->isReusable()) {
      static::invalidateBlockPluginCache();
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public static function preDelete(EntityStorageInterface $storage, array $entities) {
    parent::preDelete($storage, $entities);
    /** @var \Drupal\block_content\BlockContentInterface $block */
    foreach ($entities as $block) {
      foreach ($block->getInstances() as $instance) {
        $instance->delete();
      }
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public static function postDelete(EntityStorageInterface $storage, array $entities) {
    parent::postDelete($storage, $entities);
    /** @var \Drupal\block_content\BlockContentInterface $block */
    foreach ($entities as $block) {
      if ($block->isReusable()) {
        // If any deleted blocks are reusable clear the block cache.
        static::invalidateBlockPluginCache();
        return;
      }
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public function getInstances() {
    return \Drupal::entityTypeManager()->getStorage('block')
      ->loadByProperties([
      'plugin' => 'block_content:' . $this->uuid(),
    ]);
  }
  
  /**
   * {@inheritdoc}
   */
  public function preSaveRevision(EntityStorageInterface $storage, \stdClass $record) {
    parent::preSaveRevision($storage, $record);
    if (!$this->isNewRevision() && $this->getOriginal() && empty($record->revision_log_message)) {
      // If we are updating an existing block_content without adding a new
      // revision and the user did not supply a revision log, keep the existing
      // one.
      $record->revision_log = $this->getOriginal()
        ->getRevisionLogMessage();
    }
  }
  
  /**
   * {@inheritdoc}
   */
  public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
    /** @var \Drupal\Core\Field\BaseFieldDefinition[] $fields */
    $fields = parent::baseFieldDefinitions($entity_type);
    $fields['id']->setLabel(t('Content block ID'))
      ->setDescription(t('The content block ID.'));
    $fields['uuid']->setDescription(t('The content block UUID.'));
    $fields['revision_id']->setDescription(t('The revision ID.'));
    $fields['langcode']->setDescription(t('The content block language code.'));
    $fields['type']->setLabel(t('Block type'))
      ->setDescription(t('The block type.'));
    $fields['revision_log']->setDescription(t('The log entry explaining the changes in this revision.'));
    $fields['info'] = BaseFieldDefinition::create('string')->setLabel(t('Block description'))
      ->setDescription(t('A brief description of your block.'))
      ->setRevisionable(TRUE)
      ->setTranslatable(TRUE)
      ->setRequired(TRUE)
      ->setDisplayOptions('form', [
      'type' => 'string_textfield',
      'weight' => -5,
    ])
      ->setDisplayConfigurable('form', TRUE);
    $fields['changed'] = BaseFieldDefinition::create('changed')->setLabel(t('Changed'))
      ->setDescription(t('The time that the content block was last edited.'))
      ->setTranslatable(TRUE)
      ->setRevisionable(TRUE);
    $fields['reusable'] = BaseFieldDefinition::create('boolean')->setLabel(t('Reusable'))
      ->setDescription(t('A boolean indicating whether this block is reusable.'))
      ->setTranslatable(FALSE)
      ->setRevisionable(FALSE)
      ->setDefaultValue(TRUE);
    return $fields;
  }
  
  /**
   * {@inheritdoc}
   */
  public function setInfo($info) {
    $this->set('info', $info);
    return $this;
  }
  
  /**
   * {@inheritdoc}
   */
  public function isReusable() {
    return (bool) $this->get('reusable')->value;
  }
  
  /**
   * {@inheritdoc}
   */
  public function setReusable() {
    return $this->set('reusable', TRUE);
  }
  
  /**
   * {@inheritdoc}
   */
  public function setNonReusable() {
    return $this->set('reusable', FALSE);
  }
  
  /**
   * Invalidates the block plugin cache after changes and deletions.
   */
  protected static function invalidateBlockPluginCache() {
    // Invalidate the block cache to update content block-based derivatives.
    \Drupal::service('plugin.manager.block')->clearCachedDefinitions();
  }

}