class Fqsen

final class Fqsen {
    
    /** @var string full quallified class name */
    private $fqsen;
    
    /** @var string name of the element without path. */
    private $name;
    
    /**
     * Initializes the object.
     *
     * @throws InvalidArgumentException when $fqsen is not matching the format.
     */
    public function __construct(string $fqsen) {
        $matches = [];
        $result = preg_match('/^\\\\([a-zA-Z_\\x7f-\\xff][a-zA-Z0-9_\\x7f-\\xff\\\\]*)?(?:[:]{2}\\$?([a-zA-Z_\\x7f-\\xff][a-zA-Z0-9_\\x7f-\\xff]*))?(?:\\(\\))?$/', $fqsen, $matches);
        if ($result === 0) {
            throw new InvalidArgumentException(sprintf('"%s" is not a valid Fqsen.', $fqsen));
        }
        $this->fqsen = $fqsen;
        if (isset($matches[2])) {
            $this->name = $matches[2];
        }
        else {
            $matches = explode('\\', $fqsen);
            $name = end($matches);
            assert(is_string($name));
            $this->name = trim($name, '()');
        }
    }
    
    /**
     * converts this class to string.
     */
    public function __toString() : string {
        return $this->fqsen;
    }
    
    /**
     * Returns the name of the element without path.
     */
    public function getName() : string {
        return $this->name;
    }

}