class EntityContentBase

class EntityContentBase extends Entity implements HighestIdInterface, MigrateValidatableEntityInterface {

  /**
   * Field type plugin manager.
   *
   * @var \Drupal\Core\Field\FieldTypePluginManagerInterface
   */
  protected $fieldTypeManager;

  /**
   * The account switcher service.
   *
   * @var \Drupal\Core\Session\AccountSwitcherInterface
   */
  protected $accountSwitcher;

  /**
   * Constructs a content entity.
   *
   * @param array $configuration
   *   A configuration array containing information about the plugin instance.
   * @param string $plugin_id
   *   The plugin ID for the plugin instance.
   * @param mixed $plugin_definition
   *   The plugin implementation definition.
   * @param \Drupal\migrate\Plugin\MigrationInterface $migration
   *   The migration entity.
   * @param \Drupal\Core\Entity\EntityStorageInterface $storage
   *   The storage for this entity type.
   * @param array $bundles
   *   The list of bundles this entity type has.
   * @param \Drupal\Core\Entity\EntityFieldManagerInterface $entity_field_manager
   *   The entity field manager.
   * @param \Drupal\Core\Field\FieldTypePluginManagerInterface $field_type_manager
   *   The field type plugin manager service.
   * @param \Drupal\Core\Session\AccountSwitcherInterface $account_switcher
   *   The account switcher service.
   */
  public function __construct(array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration, EntityStorageInterface $storage, array $bundles, EntityFieldManagerInterface $entity_field_manager, FieldTypePluginManagerInterface $field_type_manager, AccountSwitcherInterface $account_switcher = NULL) {
    parent::__construct($configuration, $plugin_id, $plugin_definition, $migration, $storage, $bundles);
    $this->entityFieldManager = $entity_field_manager;
    $this->fieldTypeManager = $field_type_manager;
    $this->accountSwitcher = $account_switcher;
  }

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {
    $entity_type = static::getEntityTypeId($plugin_id);
    return new static($configuration, $plugin_id, $plugin_definition, $migration, $container
      ->get('entity_type.manager')
      ->getStorage($entity_type), array_keys($container
      ->get('entity_type.bundle.info')
      ->getBundleInfo($entity_type)), $container
      ->get('entity_field.manager'), $container
      ->get('plugin.manager.field.field_type'), $container
      ->get('account_switcher'));
  }

  /**
   * {@inheritdoc}
   *
   * @throws \Drupal\migrate\MigrateException
   *   When an entity cannot be looked up.
   * @throws \Drupal\migrate\Exception\EntityValidationException
   *   When an entity validation hasn't been passed.
   */
  public function import(Row $row, array $old_destination_id_values = []) {
    $this->rollbackAction = MigrateIdMapInterface::ROLLBACK_DELETE;
    $entity = $this
      ->getEntity($row, $old_destination_id_values);
    if (!$entity) {
      throw new MigrateException('Unable to get entity');
    }
    assert($entity instanceof ContentEntityInterface);
    if ($this
      ->isEntityValidationRequired($entity)) {
      $this
        ->validateEntity($entity);
    }
    $ids = $this
      ->save($entity, $old_destination_id_values);
    if ($this
      ->isTranslationDestination()) {
      $ids[] = $entity
        ->language()
        ->getId();
    }
    return $ids;
  }

  /**
   * {@inheritdoc}
   */
  public function isEntityValidationRequired(FieldableEntityInterface $entity) {

    // Prioritize the entity method over migration config because it won't be
    // possible to save that entity non validated.

    /* @see \Drupal\Core\Entity\ContentEntityBase::preSave() */
    return $entity
      ->isValidationRequired() || !empty($this->configuration['validate']);
  }

  /**
   * {@inheritdoc}
   */
  public function validateEntity(FieldableEntityInterface $entity) {

    // Entity validation can require the user that owns the entity. Switch to
    // use that user during validation.
    // As an example:
    // @see \Drupal\Core\Entity\Plugin\Validation\Constraint\ValidReferenceConstraint
    $account = $entity instanceof EntityOwnerInterface ? $entity
      ->getOwner() : NULL;

    // Validate account exists as the owner reference could be invalid for any
    // number of reasons.
    if ($account) {
      $this->accountSwitcher
        ->switchTo($account);
    }

    // This finally block ensures that the account is always switched back, even
    // if an exception was thrown. Any validation exceptions are intentionally
    // left unhandled. They should be caught and logged by a catch block
    // surrounding the row import and then added to the migration messages table
    // for the current row.
    try {
      $violations = $entity
        ->validate();
    } finally {
      if ($account) {
        $this->accountSwitcher
          ->switchBack();
      }
    }
    if (count($violations) > 0) {
      throw new EntityValidationException($violations);
    }
  }

  /**
   * Saves the entity.
   *
   * @param \Drupal\Core\Entity\ContentEntityInterface $entity
   *   The content entity.
   * @param array $old_destination_id_values
   *   (optional) An array of destination ID values. Defaults to an empty array.
   *
   * @return array
   *   An array containing the entity ID.
   */
  protected function save(ContentEntityInterface $entity, array $old_destination_id_values = []) {
    $entity
      ->setSyncing(TRUE);
    $entity
      ->save();
    return [
      $entity
        ->id(),
    ];
  }

  /**
   * {@inheritdoc}
   */
  public function isTranslationDestination() {
    return !empty($this->configuration['translations']);
  }

  /**
   * {@inheritdoc}
   */
  public function getIds() {
    $ids = [];
    $id_key = $this
      ->getKey('id');
    $ids[$id_key] = $this
      ->getDefinitionFromEntity($id_key);
    if ($this
      ->isTranslationDestination()) {
      $langcode_key = $this
        ->getKey('langcode');
      if (!$langcode_key) {
        throw new MigrateException(sprintf('The "%s" entity type does not support translations.', $this->storage
          ->getEntityTypeId()));
      }
      $ids[$langcode_key] = $this
        ->getDefinitionFromEntity($langcode_key);
    }
    return $ids;
  }

  /**
   * {@inheritdoc}
   */
  protected function updateEntity(EntityInterface $entity, Row $row) {
    $empty_destinations = $row
      ->getEmptyDestinationProperties();

    // By default, an update will be preserved.
    $rollback_action = MigrateIdMapInterface::ROLLBACK_PRESERVE;

    // Make sure we have the right translation.
    if ($this
      ->isTranslationDestination()) {
      $property = $this->storage
        ->getEntityType()
        ->getKey('langcode');
      if ($row
        ->hasDestinationProperty($property)) {
        $language = $row
          ->getDestinationProperty($property);
        if (!$entity
          ->hasTranslation($language)) {
          $entity
            ->addTranslation($language);

          // We're adding a translation, so delete it on rollback.
          $rollback_action = MigrateIdMapInterface::ROLLBACK_DELETE;
        }
        $entity = $entity
          ->getTranslation($language);
      }
    }

    // If the migration has specified a list of properties to be overwritten,
    // clone the row with an empty set of destination values, and re-add only
    // the specified properties.
    if (isset($this->configuration['overwrite_properties'])) {
      $empty_destinations = array_intersect($empty_destinations, $this->configuration['overwrite_properties']);
      $clone = $row
        ->cloneWithoutDestination();
      foreach ($this->configuration['overwrite_properties'] as $property) {
        $clone
          ->setDestinationProperty($property, $row
          ->getDestinationProperty($property));
      }
      $row = $clone;
    }
    foreach ($row
      ->getDestination() as $field_name => $values) {
      $field = $entity->{$field_name};
      if ($field instanceof TypedDataInterface) {
        $field
          ->setValue($values);
      }
    }
    foreach ($empty_destinations as $field_name) {
      $entity->{$field_name} = NULL;
    }
    $this
      ->setRollbackAction($row
      ->getIdMap(), $rollback_action);

    // We might have a different (translated) entity, so return it.
    return $entity;
  }

  /**
   * {@inheritdoc}
   */
  protected function processStubRow(Row $row) {
    $bundle_key = $this
      ->getKey('bundle');
    if ($bundle_key && empty($row
      ->getDestinationProperty($bundle_key))) {
      if (empty($this->bundles)) {
        throw new MigrateException('Stubbing failed, no bundles available for entity type: ' . $this->storage
          ->getEntityTypeId());
      }
      $row
        ->setDestinationProperty($bundle_key, reset($this->bundles));
    }
    $bundle = $row
      ->getDestinationProperty($bundle_key) ?? $this->storage
      ->getEntityTypeId();

    // Populate any required fields not already populated.
    $fields = $this->entityFieldManager
      ->getFieldDefinitions($this->storage
      ->getEntityTypeId(), $bundle);
    foreach ($fields as $field_name => $field_definition) {
      if ($field_definition
        ->isRequired() && is_null($row
        ->getDestinationProperty($field_name))) {

        // Use the configured default value for this specific field, if any.
        if ($default_value = $field_definition
          ->getDefaultValueLiteral()) {
          $values = $default_value;
        }
        else {

          /** @var \Drupal\Core\Field\FieldItemInterface $field_type_class */
          $field_type_class = $this->fieldTypeManager
            ->getPluginClass($field_definition
            ->getType());
          $values = $field_type_class::generateSampleValue($field_definition);
          if (is_null($values)) {

            // Handle failure to generate a sample value.
            throw new MigrateException('Stubbing failed, unable to generate value for field ' . $field_name);
          }
        }
        $row
          ->setDestinationProperty($field_name, $values);
      }
    }
  }

  /**
   * {@inheritdoc}
   */
  public function rollback(array $destination_identifier) {
    if ($this
      ->isTranslationDestination()) {

      // Attempt to remove the translation.
      $entity = $this->storage
        ->load(reset($destination_identifier));
      if ($entity && $entity instanceof TranslatableInterface) {
        if ($key = $this
          ->getKey('langcode')) {
          if (isset($destination_identifier[$key])) {
            $langcode = $destination_identifier[$key];
            if ($entity
              ->hasTranslation($langcode)) {

              // Make sure we don't remove the default translation.
              $translation = $entity
                ->getTranslation($langcode);
              if (!$translation
                ->isDefaultTranslation()) {
                $entity
                  ->removeTranslation($langcode);
                $entity
                  ->setSyncing(TRUE);
                $entity
                  ->save();
              }
            }
          }
        }
      }
    }
    else {
      parent::rollback($destination_identifier);
    }
  }

  /**
   * {@inheritdoc}
   */
  public function getHighestId() {
    $values = $this->storage
      ->getQuery()
      ->accessCheck(FALSE)
      ->sort($this
      ->getKey('id'), 'DESC')
      ->range(0, 1)
      ->execute();
    return (int) current($values);
  }

}