<?php

/**
 * @file
 * CER keeps reference fields in sync.
 */

use Drupal\Core\Entity\EntityInterface;
use Drupal\Core\Entity\FieldableEntityInterface;

/**
 * Implements hook_entity_insert().
 */
function cer_entity_insert(EntityInterface $entity) {
  cer_sync_corresponding_references($entity);
}

/**
 * Implements hook_entity_update().
 */
function cer_entity_update(EntityInterface $entity) {
  cer_sync_corresponding_references($entity);
}

/**
 * Implements hook_entity_delete().
 */
function cer_entity_delete(Drupal\Core\Entity\EntityInterface $entity) {
  cer_sync_corresponding_references($entity, TRUE);
}

/**
 * Synchronize corresponding references for an entity.
 *
 * @param \Drupal\Core\Entity\EntityInterface $entity
 *   The entity to synchronize corresponding references for.
 * @param bool $deleted
 *   Whether the entity is deleted.
 *
 * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
 * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
 */
function cer_sync_corresponding_references(EntityInterface $entity, $deleted = FALSE) {
  if (!$entity instanceof FieldableEntityInterface) {
    return;
  }

  /** @var \Drupal\cer\CorrespondingReferenceStorageInterface $storage */
  $storage = \Drupal::entityTypeManager()->getStorage('corresponding_reference');

  $references = $storage->loadValid($entity);

  foreach ($references as $reference) {
    $reference->synchronizeCorrespondingFields($entity, $deleted);
  }
}