<?php

namespace App\Jobs\InboxPipeline;

use App\Models\Profile;
use App\Util\ActivityPub\Helpers;
use App\Util\ActivityPub\HttpSignature;
use Illuminate\Bus\Queueable;
use Illuminate\Contracts\Queue\ShouldQueue;
use Illuminate\Foundation\Bus\Dispatchable;
use Illuminate\Queue\InteractsWithQueue;
use Illuminate\Queue\SerializesModels;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Lottery;

class InboxValidator implements ShouldQueue
{
    use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

    protected $username;

    protected $headers;

    protected $payload;

    public $timeout = 300;

    public $tries = 1;

    public $maxExceptions = 1;

    /**
     * Create a new job instance.
     *
     * @return void
     */
    public function __construct($username, $headers, $payload)
    {
        $this->username = $username;
        $this->headers = $headers;
        $this->payload = $payload;
    }

    /**
     * Execute the job.
     *
     * @return void
     */
    public function handle()
    {
        $username = $this->username;
        $headers = $this->headers;

        if (empty($headers) || empty($this->payload) || ! isset($headers['signature']) || ! isset($headers['date'])) {
            return null;
        }

        $payload = json_decode($this->payload, true, 8);

        $profile = Profile::whereNull('domain')->whereUsername($username)->first();

        if (empty($profile) || empty($headers) || empty($payload)) {
            return null;
        }

        if ($profile->status != null) {
            return null;
        }

        if ($this->verifySignature($headers, $profile, $payload) == true) {
            if (isset($payload['id'])) {
                $lockKey = 'pf:ap:user-inbox:activity:'.hash('sha256', $payload['id']);
                if (! Cache::add($lockKey, 1, 3600)) {
                    // Already processed after valid signature check
                    return 1;
                }
            }

            if (isset($payload['type']) && in_array($payload['type'], ['Follow', 'Accept'])) {
                ActivityHandler::dispatch($headers, $profile, $payload)->onQueue('follow');
            } else {
                $onQueue = Lottery::odds(1, 12)->winner(fn () => 'high')->loser(fn () => 'inbox')->choose();
                ActivityHandler::dispatch($headers, $profile, $payload)->onQueue($onQueue);
            }

            return null;
        }
        return null;
    }

    protected function verifySignature($headers, $profile, $payload)
    {
        $body = $this->payload;
        $bodyDecoded = $payload;
        $signature = is_array($headers['signature']) ? $headers['signature'][0] : $headers['signature'];
        $date = is_array($headers['date']) ? $headers['date'][0] : $headers['date'];
        if (! $signature) {
            return false;
        }
        if (! $date) {
            return false;
        }
        if (
            ! now()->parse($date)->gt(now()->subDays(1)) ||
            ! now()->parse($date)->lt(now()->addDays(1))
        ) {
            return false;
        }
        if (! isset($bodyDecoded['id'])) {
            return false;
        }
        $signatureData = HttpSignature::parseSignatureHeader($signature);

        if (! isset($signatureData['keyId'], $signatureData['signature'], $signatureData['headers']) || isset($signatureData['error'])) {
            return false;
        }

        $keyId = Helpers::validateUrl($signatureData['keyId']);
        $id = Helpers::validateUrl($bodyDecoded['id']);
        $keyDomain = parse_url($keyId, PHP_URL_HOST);
        $idDomain = parse_url($id, PHP_URL_HOST);
        $claimedActor = Helpers::pluckval($bodyDecoded['actor'] ?? null);
        if (is_array($claimedActor)) {
            $claimedActor = $claimedActor['id'] ?? null;
        }
        if (! $claimedActor && self::actorOptionalFor($bodyDecoded)) {
            $claimedActor = $keyId ? strtok($keyId, '#') : null;
        }
        $actorDomain = parse_url((string) $claimedActor, PHP_URL_HOST);
        if (
            isset($bodyDecoded['object'])
            && is_array($bodyDecoded['object'])
            && isset($bodyDecoded['object']['attributedTo'])
        ) {
            $attr = Helpers::pluckval($bodyDecoded['object']['attributedTo']);
            if (is_array($attr)) {
                if (isset($attr['id'])) {
                    $attr = $attr['id'];
                } else {
                    $attr = '';
                }
            }
            if (parse_url($attr, PHP_URL_HOST) !== $keyDomain) {
                return false;
            }
        }
        if (
            ! $keyDomain || ! $idDomain || ! $actorDomain
            || $keyDomain !== $idDomain || $keyDomain !== $actorDomain
        ) {
            return false;
        }
        $actor = Profile::whereKeyId($keyId)->first();
        if (! $actor) {
            $actor = Helpers::profileFirstOrNew($claimedActor);
        }
        if (! $actor) {
            return false;
        }
        // Rebind: the profile resolved by keyId must belong to the keyId host.
        // This rejects a poisoned or stale row whose remote_url host differs
        // from the request's keyId host, so a planted key_id -> attacker key
        // binding cannot authenticate.
        if (parse_url($actor->remote_url, PHP_URL_HOST) !== $keyDomain) {
            return false;
        }
        $pkey = openssl_pkey_get_public($actor->public_key);
        if (! $pkey) {
            return false;
        }
        $inboxPath = "/users/{$profile->username}/inbox";
        [$verified, $headers] = HttpSignature::verify($pkey, $signatureData, $headers, $inboxPath, $body);
        return $verified == 1;
    }

    public static function actorOptionalFor(array $payload): bool
    {
        return isset($payload['type']) && $payload['type'] === 'FeatureRequest';
    }
}