AltTextContainsLlamasConstraintValidator.php

<?php

declare (strict_types=1);
namespace Drupal\image_field_property_constraint_validation\Plugin\Validation\Constraint;

use Symfony\Component\Validator\Constraint;
use Symfony\Component\Validator\ConstraintValidator;

/**
 * Validates the alt text contains llamas.
 */
final class AltTextContainsLlamasConstraintValidator extends ConstraintValidator {
    
    /**
     * {@inheritdoc}
     */
    public function validate(mixed $value, Constraint $constraint) : void {
        if (is_string($value) && !str_contains(strtolower($value), 'llamas')) {
            $this->context
                ->buildViolation($constraint->message)
                ->setInvalidValue($value)
                ->addViolation();
        }
    }

}