class CallbackToken

class CallbackToken implements TokenInterface {
    private $callback;
    
    /**
     * @var string|null
     */
    private $customStringRepresentation;
    
    /**
     * Initializes token.
     *
     * @param callable $callback
     * @param string|null $customStringRepresentation Customize the __toString() representation of this token
     *
     * @throws \Prophecy\Exception\InvalidArgumentException
     */
    public function __construct($callback, ?string $customStringRepresentation = null) {
        if (!is_callable($callback)) {
            throw new InvalidArgumentException(sprintf('Callable expected as an argument to CallbackToken, but got %s.', gettype($callback)));
        }
        $this->callback = $callback;
        $this->customStringRepresentation = $customStringRepresentation;
    }
    
    /**
     * Scores 7 if callback returns true, false otherwise.
     *
     * @param mixed $argument
     *
     * @return false|int
     */
    public function scoreArgument($argument) {
        return call_user_func($this->callback, $argument) ? 7 : false;
    }
    
    /**
     * Returns false.
     *
     * @return bool
     */
    public function isLast() {
        return false;
    }
    
    /**
     * Returns string representation for token.
     *
     * @return string
     */
    public function __toString() {
        if ($this->customStringRepresentation !== null) {
            return $this->customStringRepresentation;
        }
        return 'callback()';
    }

}