<?php

declare(strict_types = 1);

// {{{ License
// This file is part of GNU social - https://www.gnu.org/software/social
//
// GNU social is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// GNU social is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with GNU social.  If not, see <http://www.gnu.org/licenses/>.
// }}}

/**
 * ActivityPub implementation for GNU social
 *
 * @package   GNUsocial
 * @category  API
 *
 * @author    Diogo Peralta Cordeiro <@diogo.site>
 * @copyright 2021 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

namespace Plugin\IndieAuth;

use App\Core\Event;
use App\Core\Log;
use App\Core\Modules\Plugin;
use App\Core\Router\RouteLoader;
use App\Core\Router\Router;
use App\Util\Common;
use Nyholm\Psr7\Response;
use Plugin\IndieAuth\Controller\Apps;
use Plugin\IndieAuth\Controller\OAuth2;
use Psr\Http\Message\ServerRequestInterface;
use Taproot\IndieAuth\Server;
use XML_XRD_Element_Link;

/**
 * Adds OAuth2 support to GNU social when enabled
 *
 * @copyright 2021 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */
class IndieAuth extends Plugin
{
    public const OAUTH_ACCESS_TOKEN_REL  = 'http://apinamespace.org/oauth/access_token';
    public const OAUTH_REQUEST_TOKEN_REL = 'http://apinamespace.org/oauth/request_token';
    public const OAUTH_AUTHORIZE_REL     = 'http://apinamespace.org/oauth/authorize';

    public static Server $server;

    public function onInitializePlugin()
    {
        self::$server = new Server([
            'secret'      => 'YOUR_APP_INDIEAUTH_SECRET$config["secret"] must be a string with a minimum length of 64 characters.yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee',
            'logger'      => Log::getLogger(),
            'requirePKCE' => false,
            // A path to store token data, or an object implementing TokenStorageInterface.
            'tokenStorage' => '/../data/auth_tokens/',

            // An authentication callback function, which either returns data about the current user,
            // or redirects to/implements an authentication flow.
            'authenticationHandler' => function (ServerRequestInterface $request, string $authenticationRedirect, ?string $normalizedMeUrl) {
                // If the request is authenticated, return an array with a `me` key containing the
                // canonical URL of the currently logged-in user.
                if ($actor = Common::actor()) {
                    return ['me' => $actor->getUri(Router::ABSOLUTE_URL)];
                }

                // Otherwise, redirect the user to a login page, ensuring that they will be redirected
                // back to the IndieAuth flow with query parameters intact once logged in.
                return new Response(302, ['Location' => Router::url('security_login') . '?returnUrl=' . urlencode($authenticationRedirect)]);
            },
        ]);
    }

    public function version(): string
    {
        return '3.0.0';
    }

    /**
     * This code executes when GNU social creates the page routing, and we hook
     * on this event to add our Inbox and Outbox handler for ActivityPub.
     *
     * @param RouteLoader $r the router that was initialized
     */
    public function onAddRoute(RouteLoader $r): bool
    {
        $r->connect(
            'oauth2_apps',
            '/api/v1/apps',
            Apps::class,
            ['http-methods' => ['POST']],
        );

        $r->connect(
            'oauth2_authorization_code',
            '/oauth/authorize',
            [OAuth2::class, 'handleAuthorizationEndpointRequest'],
        );

        $r->connect(
            'oauth2_token',
            '/oauth/token',
            [OAuth2::class, 'handleTokenEndpointRequest'],
        );

        return Event::next;
    }

    public function onEndHostMetaLinks(array &$links): bool
    {
        $links[] = new XML_XRD_Element_link(self::OAUTH_REQUEST_TOKEN_REL, Router::url('oauth2_apps', type: Router::ABSOLUTE_URL));
        $links[] = new XML_XRD_Element_link(self::OAUTH_AUTHORIZE_REL, Router::url('oauth2_authorize', type: Router::ABSOLUTE_URL));
        $links[] = new XML_XRD_Element_link(self::OAUTH_ACCESS_TOKEN_REL, Router::url('oauth2_token', type: Router::ABSOLUTE_URL));
        return Event::next;
    }
}