public function validate($vatNumber)
{
if (strlen($vatNumber) != 11) {
return false;
}
if (strpos($this->alphabet, $vatNumber[0]) === false) {
return false;
}
if (strpos($this->alphabet, $vatNumber[1]) === false) {
return false;
}
$checksum = substr($vatNumber, 0, 2);
if (ctype_digit($checksum)) {
$checkval = $this->validateOld($vatNumber);
} else {
$checkval = $this->validateNew($vatNumber);
}
if ($checksum != $checkval) {
return false;
}
return true;
}