class AbstractLoader

abstract class AbstractLoader implements LoaderInterface {
    
    /**
     * The namespace to load constraints from by default.
     */
    public const DEFAULT_NAMESPACE = '\\Symfony\\Component\\Validator\\Constraints\\';
    protected array $namespaces = [];
    
    /**
     * @var array<class-string, bool>
     */
    private array $namedArgumentsCache = [];
    
    /**
     * Adds a namespace alias.
     *
     * The namespace alias can be used to reference constraints from specific
     * namespaces in {@link newConstraint()}:
     *
     *     $this->addNamespaceAlias('mynamespace', '\\Acme\\Package\\Constraints\\');
     *
     *     $constraint = $this->newConstraint('mynamespace:NotNull');
     */
    protected function addNamespaceAlias(string $alias, string $namespace) : void {
        $this->namespaces[$alias] = $namespace;
    }
    
    /**
     * Creates a new constraint instance for the given constraint name.
     *
     * @param string $name    The constraint name. Either a constraint relative
     *                        to the default constraint namespace, or a fully
     *                        qualified class name. Alternatively, the constraint
     *                        may be preceded by a namespace alias and a colon.
     *                        The namespace alias must have been defined using
     *                        {@link addNamespaceAlias()}.
     * @param mixed  $options The constraint options
     *
     * @throws MappingException If the namespace prefix is undefined
     */
    protected function newConstraint(string $name, mixed $options = null) : Constraint {
        if (str_contains($name, '\\') && class_exists($name)) {
            $className = $name;
        }
        elseif (str_contains($name, ':')) {
            [
                $prefix,
                $className,
            ] = explode(':', $name, 2);
            if (!isset($this->namespaces[$prefix])) {
                throw new MappingException(\sprintf('Undefined namespace prefix "%s".', $prefix));
            }
            $className = $this->namespaces[$prefix] . $className;
        }
        else {
            $className = self::DEFAULT_NAMESPACE . $name;
        }
        if ($this->namedArgumentsCache[$className] ??= (bool) (new \ReflectionMethod($className, '__construct'))->getAttributes(HasNamedArguments::class)) {
            if (null === $options) {
                return new $className();
            }
            if (!\is_array($options)) {
                return new $className($options);
            }
            if (1 === \count($options) && isset($options['value'])) {
                return new $className($options['value']);
            }
            return new $className(...$options);
        }
        return new $className($options);
    }

}