<?php
namespace Swissup\Taxvat\Plugin\Model;

use Magento\Framework\Exception\ValidatorException;
use Magento\Framework\Exception\RemoteServiceUnavailableException;

class BillingAddressManagement
{
/**
* @var \Swissup\Taxvat\Helper\Data $helper
*/
protected $helper;
/**
* @param \Swissup\Taxvat\Helper\Data $helper
*/
public function __construct(
\Swissup\Taxvat\Helper\Data $helper
) {
$this->helper = $helper;
}

/**
* After is not used for Magento 2.2 compatibility
*
* @param \Magento\Quote\Model\BillingAddressManagement $subject
* @param callable $proceed
* @param int $cartId
* @param \Magento\Quote\Api\Data\AddressInterface $address
* @param boolean $useForShipping
* @return mixed
*/
public function aroundAssign(
\Magento\Quote\Model\BillingAddressManagement $subject,
callable $proceed,
$cartId,
\Magento\Quote\Api\Data\AddressInterface $address,
$useForShipping = false
) {
$result = $proceed($cartId, $address, $useForShipping);

if (!$this->helper->canValidateVat()) {
return $result;
}

if (!$this->helper->validateAddress($address)) {
throw new ValidatorException(__('Please enter a valid VAT number.'));
}

return $result;
}
}