class StrictConfirmationQuestion

class StrictConfirmationQuestion extends Question {
    
    /** @var non-empty-string */
    private $trueAnswerRegex;
    
    /** @var non-empty-string */
    private $falseAnswerRegex;
    
    /**
     * Constructor.s
     *
     * @param string $question         The question to ask to the user
     * @param bool   $default          The default answer to return, true or false
     * @param non-empty-string $trueAnswerRegex  A regex to match the "yes" answer
     * @param non-empty-string $falseAnswerRegex A regex to match the "no" answer
     */
    public function __construct(string $question, bool $default = true, string $trueAnswerRegex = '/^y(?:es)?$/i', string $falseAnswerRegex = '/^no?$/i') {
        parent::__construct($question, $default);
        $this->trueAnswerRegex = $trueAnswerRegex;
        $this->falseAnswerRegex = $falseAnswerRegex;
        $this->setNormalizer($this->getDefaultNormalizer());
        $this->setValidator($this->getDefaultValidator());
    }
    
    /**
     * Returns the default answer normalizer.
     */
    private function getDefaultNormalizer() : callable {
        $default = $this->getDefault();
        $trueRegex = $this->trueAnswerRegex;
        $falseRegex = $this->falseAnswerRegex;
        return static function ($answer) use ($default, $trueRegex, $falseRegex) {
            if (is_bool($answer)) {
                return $answer;
            }
            if (empty($answer) && !empty($default)) {
                return $default;
            }
            if (Preg::isMatch($trueRegex, $answer)) {
                return true;
            }
            if (Preg::isMatch($falseRegex, $answer)) {
                return false;
            }
            return null;
        };
    }
    
    /**
     * Returns the default answer validator.
     */
    private function getDefaultValidator() : callable {
        return static function ($answer) : bool {
            if (!is_bool($answer)) {
                throw new InvalidArgumentException('Please answer yes, y, no, or n.');
            }
            return $answer;
        };
    }

}