Phalcon\Validation\Validator\CardNumber::validate PHP Method

    public function validate(Validation $validation, $attribute)
    {
        $value = preg_replace('/[^\\d]/', '', $validation->getValue($attribute));
        $message = $this->hasOption('message') ? $this->getOption('message') : 'Credit card number is invalid';
        if ($this->hasOption('type')) {
            $type = $this->getOption('type');
            switch ($type) {
                case CardNumber::AMERICAN_EXPRESS:
                    $issuer = substr($value, 0, 2);
                    $result = true === in_array($issuer, [34, 37]);
                    break;
                case CardNumber::MASTERCARD:
                    $issuer = substr($value, 0, 2);
                    $result = true === in_array($issuer, [51, 52, 53, 54, 55]);
                    break;
                case CardNumber::VISA:
                    $issuer = $value[0];
                    $result = $issuer == 4;
                    break;
                default:
                    throw new Exception('Incorrect type specifier');
            }
            if (false === $result) {
                $validation->appendMessage(new Message($message, $attribute, 'CardNumber'));
                return false;
            }
        }
        $value = strrev($value);
        $checkSum = 0;
        for ($i = 0; $i < strlen($value); $i++) {
            if ($i % 2 == 0) {
                $temp = $value[$i];
            } else {
                $temp = $value[$i] * 2;
                if ($temp > 9) {
                    $temp -= 9;
                }
            }
            $checkSum += $temp;
        }
        if ($checkSum % 10 != 0) {
            $validation->appendMessage(new Message($message, $attribute, 'CardNumber'));
            return false;
        }
        return true;
    }