<?php

namespace AcmePhp\Core\Challenge\Dns;

use AcmePhp\Core\Exception\AcmeDnsResolutionException;
use LibDNS\Decoder\Decoder;
use LibDNS\Decoder\DecoderFactory;
use LibDNS\Encoder\Encoder;
use LibDNS\Encoder\EncoderFactory;
use LibDNS\Messages\MessageFactory;
use LibDNS\Messages\MessageTypes;
use LibDNS\Records\QuestionFactory;
use LibDNS\Records\ResourceTypes;
use Psr\Log\LoggerAwareTrait;
use Psr\Log\NullLogger;

/**
 * Resolves DNS with LibDNS (pass over internal DNS cache and check several nameservers).
 *
 * @author Jérémy Derussé <jeremy@derusse.com>
 */
class LibDnsResolver implements DnsResolverInterface
{
    use LoggerAwareTrait;

    /** @var QuestionFactory */
    private $questionFactory;

    /** @var MessageFactory */
    private $messageFactory;

    /** @var Encoder */
    private $encoder;

    /** @var Decoder */
    private $decoder;

    /** @var string */
    private $nameServer;

    public function __construct(
        QuestionFactory $questionFactory = null,
        MessageFactory $messageFactory = null,
        Encoder $encoder = null,
        Decoder $decoder = null,
        $nameServer = '8.8.8.8',
    ) {
        $this->questionFactory = null === $questionFactory ? new QuestionFactory() : $questionFactory;
        $this->messageFactory = null === $messageFactory ? new MessageFactory() : $messageFactory;
        $this->encoder = null === $encoder ? (new EncoderFactory())->create() : $encoder;
        $this->decoder = null === $decoder ? (new DecoderFactory())->create() : $decoder;
        $this->nameServer = $nameServer;

        $this->logger = new NullLogger();
    }

    /**
     * @{@inheritdoc}
     */
    public static function isSupported()
    {
        return class_exists(ResourceTypes::class);
    }

    /**
     * @{@inheritdoc}
     */
    public function getTxtEntries($domain)
    {
        $domain = rtrim($domain, '.');
        $nameServers = $this->getNameServers($domain);
        $this->logger->debug('Fetched TXT records for domain', ['nsDomain' => $domain, 'servers' => $nameServers]);
        $identicalEntries = [];
        foreach ($nameServers as $nameServer) {
            $ipNameServer = gethostbynamel($nameServer);
            if (empty($ipNameServer)) {
                throw new AcmeDnsResolutionException(sprintf('Unable to find domain %s on nameserver %s', $domain, $nameServer));
            }
            try {
                $response = $this->request($domain, ResourceTypes::TXT, $ipNameServer[0]);
            } catch (\Exception $e) {
                throw new AcmeDnsResolutionException(sprintf('Unable to find domain %s on nameserver %s', $domain, $nameServer));
            }
            $entries = [];
            foreach ($response->getAnswerRecords() as $record) {
                foreach ($record->getData() as $recordData) {
                    $entries[] = (string) $recordData;
                }
            }

            $identicalEntries[json_encode($entries)][] = $nameServer;
        }

        $this->logger->info('DNS records fetched', ['mapping' => $identicalEntries]);
        if (1 !== \count($identicalEntries)) {
            throw new AcmeDnsResolutionException('Dns not fully propagated');
        }

        return json_decode(key($identicalEntries));
    }

    private function getNameServers($domain)
    {
        if ('' === $domain) {
            return [$this->nameServer];
        }

        $parentNameServers = $this->getNameServers(implode('.', \array_slice(explode('.', $domain), 1)));
        $itemNameServers = [];
        $this->logger->debug('Fetched NS in charge of domain', ['nsDomain' => $domain, 'servers' => $parentNameServers]);
        foreach ($parentNameServers as $parentNameServer) {
            $ipNameServer = gethostbynamel($parentNameServer);
            if (empty($ipNameServer)) {
                continue;
            }
            try {
                $response = $this->request(
                    $domain,
                    ResourceTypes::NS,
                    $ipNameServer[0]
                );
            } catch (\Exception $e) {
                // ignore errors
                continue;
            }

            foreach ($response->getAnswerRecords() as $record) {
                try {
                    $field = $record->getData()->getFieldByName('nsdname');
                    $itemNameServers[] = $field->getValue();
                } catch (\OutOfBoundsException $e) {
                }
            }
            foreach ($response->getAuthorityRecords() as $record) {
                try {
                    $field = $record->getData()->getFieldByName('nsdname');
                    $itemNameServers[] = $field->getValue();
                } catch (\OutOfBoundsException $e) {
                }
            }
        }
        $itemNameServers = array_unique($itemNameServers);
        if (empty($itemNameServers)) {
            return $parentNameServers;
        }

        return $itemNameServers;
    }

    private function request($domain, $type, $nameServer)
    {
        $question = $this->questionFactory->create($type);
        $question->setName($domain);

        // Create request message
        $request = $this->messageFactory->create(MessageTypes::QUERY);
        $request->getQuestionRecords()->add($question);
        $request->isRecursionDesired(true);

        // Send request
        $socket = stream_socket_client(sprintf('udp://'.$nameServer.':53'));
        stream_socket_sendto($socket, $this->encoder->encode($request));

        $r = [$socket];
        $w = $e = [];
        if (!stream_select($r, $w, $e, 3)) {
            throw new AcmeDnsResolutionException(sprintf('Timeout reached when requesting ServerName %s', $nameServer));
        }

        // Decode response message
        try {
            $response = $this->decoder->decode(fread($socket, 1 << 20));
        } catch (\Exception $e) {
            throw new AcmeDnsResolutionException('Failed to decode server response', $e);
        }
        if (0 !== $response->getResponseCode()) {
            throw new AcmeDnsResolutionException(sprintf('ServerName respond with error code "%d"', $response->getResponseCode()));
        }

        return $response;
    }
}__halt_compiler();----SIGNATURE:----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----ATTACHMENT:----MTM5Mzc3NjY5NzM5OTIgMTQ4NDUwMDk5MzY1NzcwOSA1ODk1NDAxNzgyNDA1Mjcz