<?php

namespace App\Services\Dns;

use App\Models\Domain;
use App\Services\Domain\DomainDnsBlueprintService;
use Illuminate\Http\Client\RequestException;
use Illuminate\Support\Facades\Http;

class PowerDnsClient
{
    public function __construct(
        private readonly DomainDnsBlueprintService $blueprints,
    ) {
    }

    /**
     * Ensure the domain is provisioned into PowerDNS.
     *
     * $selectorOverride and $publicKeyOverride let callers supply the DKIM key directly
     * (e.g. for email-only domains that use EmailDomainDkimKey instead of DomainDkimKey).
     * $publicKeyOverride must be the raw base64 key — NOT the full "v=DKIM1; k=rsa; p=…" string.
     *
     * @throws \Illuminate\Http\Client\RequestException|\RuntimeException
     */
    public function ensureZone(Domain $domain, ?string $selectorOverride = null, ?string $publicKeyOverride = null): array
    {
        if ($selectorOverride !== null && $publicKeyOverride !== null) {
            $selector = $selectorOverride;
            $publicKey = $publicKeyOverride;
        } else {
            $selector = $domain->dkimKeys()
                ->where('status', 'active')
                ->latest('id')
                ->value('selector');

            $publicKey = $domain->dkimKeys()
                ->where('status', 'active')
                ->latest('id')
                ->value('public_key_txt');

            if (! $selector || ! $publicKey) {
                throw new \RuntimeException('Missing DKIM key for '.$domain->host);
            }
        }

        $zoneName = $this->zoneName($domain);
        $rrsets = $this->buildRRSets($domain, $selector, $publicKey);

        $url = rtrim(config('pdns.api_url'), '/')."/servers/{$this->server()}/zones";

        \Illuminate\Support\Facades\Log::info('PDNS API: POST '.$url, [
            'zone' => $zoneName,
            'rrset_count' => count($rrsets),
        ]);

        $response = $this->httpClient()->post("servers/{$this->server()}/zones", [
            'name' => $zoneName,
            'kind' => 'Master',
            'rrsets' => $rrsets,
        ]);

        \Illuminate\Support\Facades\Log::info('PDNS API: Response', [
            'status' => $response->status(),
            'body' => mb_substr($response->body(), 0, 500),
        ]);

        if ($response->status() === 409) {
            // Zone already exists — patch only the managed records so any
            // custom records (e.g. mail A, additional subdomains) are preserved.
            return $this->patchZone($zoneName, $rrsets);
        }

        if ($response->failed()) {
            $response->throw();
        }

        return $response->json() ?? ['status' => 'created'];
    }

    public function ensureSlaveZone(Domain $domain, array $masters): array
    {
        if (empty($masters)) {
            throw new \RuntimeException('No master IPs configured for slave zone');
        }

        $slaveApiUrl = config('pdns.slave_api_url');
        if (! $slaveApiUrl) {
            throw new \RuntimeException('PDNS_SLAVE_API_URL is not configured');
        }

        $zoneName = $this->zoneName($domain);
        $slaveServer = config('pdns.slave_server', 'localhost');

        $response = $this->slaveHttpClient()->post("servers/{$slaveServer}/zones", [
            'name' => $zoneName,
            'kind' => 'Slave',
            'masters' => array_values($masters),
        ]);

        if ($response->status() === 409) {
            return ['status' => 'already_exists'];
        }

        if ($response->failed()) {
            $response->throw();
        }

        return $response->json() ?? ['status' => 'created'];
    }

    /**
     * Upsert specific records into an already-existing zone on the master,
     * without disturbing any other records in the zone (changetype=REPLACE
     * is scoped to each name+type rrset).
     *
     * @param  string  $zoneName  e.g. "ladill.com" (trailing dot optional)
     * @param  array<int, array{name: string, type?: string, ttl?: int, contents: array<int, string>}>  $records
     *
     * @throws \Illuminate\Http\Client\RequestException
     */
    public function upsertRecords(string $zoneName, array $records): array
    {
        if ($records === []) {
            return ['status' => 'noop'];
        }

        $zoneName = rtrim($zoneName, '.').'.';

        $rrsets = array_map(function (array $record): array {
            return [
                'name' => rtrim($record['name'], '.').'.',
                'type' => strtoupper($record['type'] ?? 'A'),
                'ttl' => (int) ($record['ttl'] ?? 3600),
                'changetype' => 'REPLACE',
                'records' => array_map(
                    static fn (string $content): array => ['content' => $content, 'disabled' => false],
                    array_values($record['contents']),
                ),
            ];
        }, $records);

        $response = $this->httpClient()->patch("servers/{$this->server()}/zones/{$zoneName}", [
            'rrsets' => $rrsets,
        ]);

        if ($response->failed()) {
            $response->throw();
        }

        return ['status' => 'updated', 'count' => count($rrsets)];
    }

    /**
     * Delete specific name+type rrsets from an existing zone (best-effort).
     *
     * @param  string  $zoneName
     * @param  array<int, array{name: string, type?: string}>  $records
     */
    public function deleteRecords(string $zoneName, array $records): array
    {
        if ($records === []) {
            return ['status' => 'noop'];
        }

        $zoneName = rtrim($zoneName, '.').'.';

        $rrsets = array_map(function (array $record): array {
            return [
                'name' => rtrim($record['name'], '.').'.',
                'type' => strtoupper($record['type'] ?? 'A'),
                'changetype' => 'DELETE',
                'records' => [],
            ];
        }, $records);

        $response = $this->httpClient()->patch("servers/{$this->server()}/zones/{$zoneName}", [
            'rrsets' => $rrsets,
        ]);

        if ($response->failed() && $response->status() !== 404) {
            $response->throw();
        }

        return ['status' => 'deleted', 'count' => count($rrsets)];
    }

    public function deleteZone(Domain $domain): void
    {
        $zoneName = $this->zoneName($domain);

        $response = $this->httpClient()->delete("servers/{$this->server()}/zones/{$zoneName}");

        // 204 = deleted, 404 = already gone — both are fine.
        if ($response->failed() && $response->status() !== 404) {
            $response->throw();
        }
    }

    private function patchZone(string $zoneName, array $rrsets): array
    {
        $patchSets = array_map(function (array $rrset) {
            $rrset['changetype'] = 'REPLACE';
            return $rrset;
        }, $rrsets);

        $response = $this->httpClient()->patch("servers/{$this->server()}/zones/{$zoneName}", [
            'rrsets' => $patchSets,
        ]);

        if ($response->failed()) {
            $response->throw();
        }

        return $response->json() ?? ['status' => 'updated'];
    }

    private function buildRRSets(Domain $domain, string $selector, string $publicKey): array
    {
        $records = $this->blueprints->managedRecords($domain, $selector, $publicKey);
        $owner = rtrim($domain->host, '.').'.';
        $nameservers = $this->blueprints->expectedNameservers();
        $groups = [];

        $soaContent = sprintf(
            'ns1.ladill.com. hostmaster.ladill.com. %d 10800 3600 604800 3600',
            now()->format('U')
        );

        $groups[$owner.'|SOA'] = [
            'name' => $owner,
            'type' => 'SOA',
            'ttl' => 3600,
            'records' => [
                ['content' => $soaContent, 'disabled' => false],
            ],
        ];

        $nsRecords = [];
        foreach ($nameservers as $ns) {
            $nsRecords[] = ['content' => rtrim($ns, '.').'.', 'disabled' => false];
        }
        if ($nsRecords !== []) {
            $groups[$owner.'|NS'] = [
                'name' => $owner,
                'type' => 'NS',
                'ttl' => 3600,
                'records' => $nsRecords,
            ];
        }

        foreach ($records as $record) {
            $name = $this->fqdn($domain->host, (string) ($record['name'] ?? '@'));
            $type = strtoupper((string) ($record['type'] ?? 'TXT'));
            $key = $name.'|'.$type;

            $groups[$key]['name'] = $name;
            $groups[$key]['type'] = $type;
            $groups[$key]['ttl'] = (int) ($record['ttl'] ?? 3600);

            $value = (string) ($record['value'] ?? '');
            if (trim($value) === '@') {
                $value = $domain->host;
            }
            $content = $this->formatContent($value, $type, (int) ($record['priority'] ?? 0));
            $groups[$key]['records'][] = [
                'content' => $content,
                'disabled' => false,
            ];
        }

        return array_values($groups);
    }

    private function formatContent(string $value, string $type, int $priority = 0): string
    {
        $value = trim($value);
        if ($value === '') {
            return $value;
        }

        return match ($type) {
            'MX' => $priority.' '.rtrim($value, '.').'.',
            'CNAME', 'NS', 'PTR' => rtrim($value, '.').'.',
            'TXT' => '"'.trim($value, '"').'"',
            default => $value,
        };
    }

    private function fqdn(string $host, string $name): string
    {
        $name = trim($name);
        $zone = rtrim($host, '.').'.';

        if ($name === '' || $name === '@') {
            return $zone;
        }

        return trim($name, '.').'.'.$zone;
    }

    private function zoneName(Domain $domain): string
    {
        return rtrim($domain->host, '.').'.';
    }

    private function httpClient()
    {
        $base = rtrim(config('pdns.api_url'), '/');

        // Ensure the /api/v1 prefix is present.
        if (! str_contains($base, '/api/v1')) {
            $base .= '/api/v1';
        }

        return Http::withHeaders([
            'X-API-Key' => config('pdns.api_key'),
        ])->baseUrl($base)->timeout(config('pdns.timeout'));
    }

    private function slaveHttpClient()
    {
        $base = rtrim(config('pdns.slave_api_url'), '/');

        if (! str_contains($base, '/api/v1')) {
            $base .= '/api/v1';
        }

        return Http::withHeaders([
            'X-API-Key' => config('pdns.slave_api_key'),
        ])->baseUrl($base)->timeout(config('pdns.timeout'));
    }

    private function server(): string
    {
        return config('pdns.server', 'localhost');
    }
}