pm-4.1.x-dev/src/Plugin/Validation/Constraint/PmExclusiveChildConstraintValidator.php

<?php

declare(strict_types=1);

namespace Drupal\pm\Plugin\Validation\Constraint;

use Drupal\Core\DependencyInjection\ContainerInjectionInterface;
use Drupal\Core\Entity\EntityTypeManagerInterface;
use Drupal\Core\Field\EntityReferenceFieldItemList;
use Drupal\pm\Service\PmConfig;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

/**
 * Validates the Exclusive Child constraint.
 */
final class PmExclusiveChildConstraintValidator extends ConstraintValidator implements ContainerInjectionInterface {

  /**
   * Constructs the object.
   */
  public function __construct(
    private readonly EntityTypeManagerInterface $entityTypeManager,
    private readonly PmConfig $pmConfig
  ) {}

  /**
   * {@inheritdoc}
   */
  public static function create(ContainerInterface $container): self {
    return new self(
      $container->get('entity_type.manager'),
      $container->get('pm.config')
    );
  }

  /**
   * {@inheritdoc}
   */
  public function validate(mixed $item, Constraint $constraint): void {
    if (!$item instanceof EntityReferenceFieldItemList) {
      throw new \InvalidArgumentException(
        sprintf('The validated value must be instance of \Drupal\Core\Field\EntityReferenceFieldItemList, %s was given.', get_debug_type($item))
      );
    }
    $entity = $item->getEntity();
    $child_ref_field_name = $this->pmConfig->getChildReferenceFieldName($entity->getEntityTypeId(), $entity->bundle());
    $storage = $this
      ->entityTypeManager
      ->getStorage($entity->getEntityTypeId());

    $referenced_items = $item->referencedEntities();
    $parent_id = $entity->id();
    foreach ($referenced_items as $referenced_item) {
      $ref_id = $referenced_item->id();
      $count = $storage
        ->getQuery()
        ->accessCheck(FALSE)
        ->condition('id', $parent_id, '<>')
        ->condition($child_ref_field_name, $ref_id)
        ->count()
        ->execute();
      if ($count) {
        $this->context->addViolation($constraint->message, [
          '%label' => $referenced_item->label(),
          '%id' => $referenced_item->id(),
          '%parent_label' => $entity->getEntityType()->getLabel(),
        ]);
      }
    }

  }

}