<?php

namespace Egulias\EmailValidator\Validation;

use Egulias\EmailValidator\EmailLexer;
use Egulias\EmailValidator\Result\InvalidEmail;
use Egulias\EmailValidator\Result\Reason\DomainAcceptsNoMail;
use Egulias\EmailValidator\Result\Reason\LocalOrReservedDomain;
use Egulias\EmailValidator\Result\Reason\NoDNSRecord as ReasonNoDNSRecord;
use Egulias\EmailValidator\Result\Reason\UnableToGetDNSRecord;
use Egulias\EmailValidator\Warning\NoDNSMXRecord;

class DNSCheckValidation implements EmailValidation
{
    /**
     * @var int
     */
    protected const DNS_RECORD_TYPES_TO_CHECK = DNS_MX + DNS_A + DNS_AAAA;

    /**
     * Reserved Top Level DNS Names (https://tools.ietf.org/html/rfc2606#section-2),
     * mDNS and private DNS Namespaces (https://tools.ietf.org/html/rfc6762#appendix-G)
     */
    public const RESERVED_DNS_TOP_LEVEL_NAMES = [
        // Reserved Top Level DNS Names
        'test',
        'example',
        'invalid',
        'localhost',

        // mDNS
        'local',

        // Private DNS Namespaces
        'intranet',
        'internal',
        'private',
        'corp',
        'home',
        'lan',
    ];
    
    /**
     * @var array
     */
    private $warnings = [];

    /**
     * @var InvalidEmail|null
     */
    private $error;

    /**
     * @var array
     */
    private $mxRecords = [];

    /**
     * @var DNSGetRecordWrapper
     */
    private $dnsGetRecord;

    public function __construct(?DNSGetRecordWrapper $dnsGetRecord = null)
    {
        if (!function_exists('idn_to_ascii')) {
            throw new \LogicException(sprintf('The %s class requires the Intl extension.', __CLASS__));
        }

        if ($dnsGetRecord == null) {
            $dnsGetRecord = new DNSGetRecordWrapper();
        }

        $this->dnsGetRecord = $dnsGetRecord;
    }

    public function isValid(string $email, EmailLexer $emailLexer) : bool
    {
        // use the input to check DNS if we cannot extract something similar to a domain
        $host = $email;

        // Arguable pattern to extract the domain. Not aiming to validate the domain nor the email
        if (false !== $lastAtPos = strrpos($email, '@')) {
            $host = substr($email, $lastAtPos + 1);
        }

        // Get the domain parts
        $hostParts = explode('.', $host);

        $isLocalDomain = count($hostParts) <= 1;
        $isReservedTopLevel = in_array($hostParts[(count($hostParts) - 1)], self::RESERVED_DNS_TOP_LEVEL_NAMES, true);

        // Exclude reserved top level DNS names
        if ($isLocalDomain || $isReservedTopLevel) {
            $this->error = new InvalidEmail(new LocalOrReservedDomain(), $host);
            return false;
        }

        return $this->checkDns($host);
    }

    public function getError() : ?InvalidEmail
    {
        return $this->error;
    }

    public function getWarnings() : array
    {
        return $this->warnings;
    }

    /**
     * @param string $host
     *
     * @return bool
     */
    protected function checkDns($host)
    {
        $variant = INTL_IDNA_VARIANT_UTS46;

        $host = rtrim(idn_to_ascii($host, IDNA_DEFAULT, $variant), '.') . '.';

        return $this->validateDnsRecords($host);
    }


    /**
     * Validate the DNS records for given host.
     *
     * @param string $host A set of DNS records in the format returned by dns_get_record.
     *
     * @return bool True on success.
     */
    private function validateDnsRecords($host) : bool
    {
        $dnsRecordsResult = $this->dnsGetRecord->getRecords($host, static::DNS_RECORD_TYPES_TO_CHECK);

        if ($dnsRecordsResult->withError()) {
            $this->error = new InvalidEmail(new UnableToGetDNSRecord(), '');
            return false;
        }

        $dnsRecords = $dnsRecordsResult->getRecords();

        // No MX, A or AAAA DNS records
        if ($dnsRecords === []) {
            $this->error = new InvalidEmail(new ReasonNoDNSRecord(), '');
            return false;
        }

        // For each DNS record
        foreach ($dnsRecords as $dnsRecord) {
            if (!$this->validateMXRecord($dnsRecord)) {
                // No MX records (fallback to A or AAAA records)
                if (empty($this->mxRecords)) {
                    $this->warnings[NoDNSMXRecord::CODE] = new NoDNSMXRecord();
                }
                return false;
            }
        }
        return true;
    }

    /**
     * Validate an MX record
     *
     * @param array $dnsRecord Given DNS record.
     *
     * @return bool True if valid.
     */
    private function validateMxRecord($dnsRecord) : bool
    {
        if (!isset($dnsRecord['type'])) {
            $this->error = new InvalidEmail(new ReasonNoDNSRecord(), '');
            return false;
        }

        if ($dnsRecord['type'] !== 'MX') {
            return true;
        }

        // "Null MX" record indicates the domain accepts no mail (https://tools.ietf.org/html/rfc7505)
        if (empty($dnsRecord['target']) || $dnsRecord['target'] === '.') {
            $this->error = new InvalidEmail(new DomainAcceptsNoMail(), "");
            return false;
        }

        $this->mxRecords[] = $dnsRecord;

        return true;
    }
}

• [D] Exception
• [D] Extra
• [F] DNSCheckValidation.php
  Delete
• [F] DNSGetRecordWrapper.php
  Delete
• [F] DNSRecords.php
  Delete
• [F] EmailValidation.php
  Delete
• [F] MessageIDValidation.php
  Delete
• [F] MultipleValidationWithAnd.php
  Delete
• [F] NoRFCWarningsValidation.php
  Delete
• [F] RFCValidation.php
  Delete

How To Payment

Simple Steps to Complete Your Payment Securely and Efficiently

Making a payment on our website is quick and secure. Start by logging in or creating an account. Select your preferred payment method, input the required details, and review the information. Once you confirm everything is correct, click on the "Submit Payment" button. You’ll receive instant confirmation and can track your payment status through your account dashboard. It’s an easy and secure process.

• Go to the Payment Section: Access the payment area on our website or app.
• Choose Your Payment Method: Select your preferred payment option.
• Enter Payment Details: Provide the necessary payment information.
• Verify Your Information: Check that all details are correct.
• Confirm Your Payment: Click "Submit Payment" to complete the transaction.