DragonBe\Vies\Validator\ValidatorCZ::validate PHP Method

    public function validate($vatNumber)
    {
        if (strlen($vatNumber) != 8) {
            return false;
        }
        if (intval($vatNumber[0] == 9)) {
            return false;
        }
        $weights = array(8, 7, 6, 5, 4, 3, 2);
        $checksum = (int) $vatNumber[7];
        $checkbase = $this->sumWeights($weights, $vatNumber);
        $checkval = $checkbase % 11 ? ceil($checkbase / 11.1) * 11 : $checkbase % 11 + 11;
        if ($checksum != $checkval - $checkbase) {
            return false;
        }
        return true;
    }