class EnumRequirement

final class EnumRequirement implements \Stringable {
    private string $requirement;
    
    /**
     * @template T of \BackedEnum
     *
     * @param class-string<T>|list<T> $cases
     */
    public function __construct(string|array $cases = []) {
        if (\is_string($cases)) {
            if (!is_subclass_of($cases, \BackedEnum::class, true)) {
                throw new InvalidArgumentException(\sprintf('"%s" is not a "BackedEnum" class.', $cases));
            }
            $cases = $cases::cases();
        }
        else {
            $class = null;
            foreach ($cases as $case) {
                if (!$case instanceof \BackedEnum) {
                    throw new InvalidArgumentException(\sprintf('Case must be a "BackedEnum" instance, "%s" given.', get_debug_type($case)));
                }
                $class ??= $case::class;
                if (!$case instanceof $class) {
                    throw new InvalidArgumentException(\sprintf('"%s::%s" is not a case of "%s".', get_debug_type($case), $case->name, $class));
                }
            }
        }
        $this->requirement = implode('|', array_map(static fn($e) => preg_quote($e->value), $cases));
    }
    public function __toString() : string {
        return $this->requirement;
    }

}