<?php

namespace App\Services\CardDav;

use App\Contracts\CardDav\CardDavClientInterface;
use GuzzleHttp\ClientInterface;
use GuzzleHttp\Exception\GuzzleException;
use RuntimeException;
use SimpleXMLElement;
use Throwable;

class CardDavClient implements CardDavClientInterface
{
    public function __construct(
        private readonly ClientInterface $http,
    ) {}

    public function fetchCards(): array
    {
        try {
            $cards = $this->fetchCardsWithReport();

            if ($cards !== []) {
                return $cards;
            }
        } catch (GuzzleException|RuntimeException) {
            // Some CardDAV servers restrict addressbook-query. Fall back to PROPFIND + GET.
        }

        return $this->fetchCardsWithPropfind();
    }

    /**
     * @return array<int, CardDavRemoteCard>
     */
    private function fetchCardsWithReport(): array
    {
        $url = rtrim((string) config('relais_sms.carddav.url'), '/').'/';
        $username = (string) config('relais_sms.carddav.username');
        $password = (string) config('relais_sms.carddav.password');

        $this->ensureConfigured($url, $username, $password);

        $response = $this->http->request('REPORT', $url, [
            'auth' => [$username, $password],
            'headers' => [
                'Content-Type' => 'application/xml; charset=utf-8',
                'Depth' => '1',
            ],
            'body' => <<<'XML'
<?xml version="1.0" encoding="utf-8" ?>
<c:addressbook-query xmlns:d="DAV:" xmlns:c="urn:ietf:params:xml:ns:carddav">
  <d:prop>
    <d:getetag />
    <c:address-data />
  </d:prop>
</c:addressbook-query>
XML,
            'timeout' => (float) config('relais_sms.carddav.timeout'),
        ]);

        return $this->parseReport((string) $response->getBody());
    }

    /**
     * @return array<int, CardDavRemoteCard>
     */
    private function fetchCardsWithPropfind(): array
    {
        $url = rtrim((string) config('relais_sms.carddav.url'), '/').'/';
        $username = (string) config('relais_sms.carddav.username');
        $password = (string) config('relais_sms.carddav.password');

        $this->ensureConfigured($url, $username, $password);

        $response = $this->http->request('PROPFIND', $url, [
            'auth' => [$username, $password],
            'headers' => [
                'Content-Type' => 'application/xml; charset=utf-8',
                'Depth' => '1',
            ],
            'body' => <<<'XML'
<?xml version="1.0" encoding="utf-8" ?>
<d:propfind xmlns:d="DAV:">
  <d:prop>
    <d:getetag />
  </d:prop>
</d:propfind>
XML,
            'timeout' => (float) config('relais_sms.carddav.timeout'),
        ]);

        $entries = $this->parsePropfind((string) $response->getBody(), $url);
        $cards = [];

        foreach ($entries as $entry) {
            $cardResponse = $this->http->request('GET', $entry['url'], [
                'auth' => [$username, $password],
                'headers' => [
                    'Accept' => 'text/vcard,text/x-vcard,text/plain,*/*',
                ],
                'timeout' => (float) config('relais_sms.carddav.timeout'),
            ]);

            $cards[] = new CardDavRemoteCard(
                href: $entry['href'],
                etag: $entry['etag'],
                vcard: (string) $cardResponse->getBody(),
            );
        }

        return $cards;
    }

    private function ensureConfigured(string $url, string $username, string $password): void
    {
        if ($url === '/' || $username === '' || $password === '') {
            throw new RuntimeException('Configuration CardDAV incomplete.');
        }
    }

    /**
     * @return array<int, CardDavRemoteCard>
     */
    private function parseReport(string $xml): array
    {
        try {
            $document = new SimpleXMLElement($xml);
        } catch (Throwable $exception) {
            throw new RuntimeException('Reponse CardDAV REPORT illisible.', previous: $exception);
        }

        $document->registerXPathNamespace('d', 'DAV:');
        $responses = $document->xpath('//d:response') ?: [];
        $cards = [];

        foreach ($responses as $response) {
            $response->registerXPathNamespace('d', 'DAV:');
            $response->registerXPathNamespace('c', 'urn:ietf:params:xml:ns:carddav');

            $hrefNodes = $response->xpath('./d:href') ?: [];
            $cardNodes = $response->xpath('.//c:address-data') ?: [];
            $href = trim((string) ($hrefNodes[0] ?? ''));
            $vcard = (string) ($cardNodes[0] ?? '');

            if ($href === '' || trim($vcard) === '') {
                continue;
            }

            $etagNodes = $response->xpath('.//d:getetag') ?: [];
            $cards[] = new CardDavRemoteCard(
                href: $href,
                etag: trim((string) ($etagNodes[0] ?? ''), '"') ?: null,
                vcard: $vcard,
            );
        }

        return $cards;
    }

    /**
     * @return array<int, array{href: string, etag: ?string, url: string}>
     */
    private function parsePropfind(string $xml, string $baseUrl): array
    {
        try {
            $document = new SimpleXMLElement($xml);
        } catch (Throwable $exception) {
            throw new RuntimeException('Reponse CardDAV PROPFIND illisible.', previous: $exception);
        }

        $document->registerXPathNamespace('d', 'DAV:');
        $responses = $document->xpath('//d:response') ?: [];
        $entries = [];

        foreach ($responses as $response) {
            $response->registerXPathNamespace('d', 'DAV:');
            $hrefNodes = $response->xpath('./d:href') ?: [];
            $href = trim((string) ($hrefNodes[0] ?? ''));

            if ($href === '' || ! str_ends_with(strtolower(parse_url($href, PHP_URL_PATH) ?: $href), '.vcf')) {
                continue;
            }

            $etagNodes = $response->xpath('.//d:getetag') ?: [];
            $entries[] = [
                'href' => $href,
                'etag' => trim((string) ($etagNodes[0] ?? ''), '"') ?: null,
                'url' => $this->absoluteUrl($baseUrl, $href),
            ];
        }

        return $entries;
    }

    private function absoluteUrl(string $baseUrl, string $href): string
    {
        if (parse_url($href, PHP_URL_SCHEME)) {
            return $href;
        }

        $base = parse_url($baseUrl);

        if (! isset($base['scheme'], $base['host'])) {
            throw new RuntimeException('URL CardDAV invalide.');
        }

        $port = isset($base['port']) ? ':'.$base['port'] : '';
        $path = str_starts_with($href, '/') ? $href : rtrim((string) ($base['path'] ?? ''), '/').'/'.$href;

        return $base['scheme'].'://'.$base['host'].$port.$path;
    }
}