<?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 <mail@diogo.site>
 * @author    Hugo Sales <hugo@hsal.es>
 * @copyright 2022 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

namespace Plugin\OAuth2;

use App\Core\Event;
use App\Core\Modules\Plugin;
use App\Core\Router;
use App\Util\Common;
use DateInterval;
use EventResult;
use Exception;
use League\OAuth2\Server\AuthorizationServer;
use League\OAuth2\Server\CryptKey;
use League\OAuth2\Server\Grant\AuthCodeGrant;
use Plugin\OAuth2\Controller as C;
use Plugin\OAuth2\Util\ExpandedBearerTokenResponse;
use XML_XRD_Element_Link;

/**
 * Adds OAuth2 support to GNU social when enabled
 *
 * @copyright 2022 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */
class OAuth2 extends Plugin
{
    public const OAUTH_REQUEST_TOKEN_REL                     = 'http://apinamespace.org/oauth/request_token';
    public const OAUTH_ACCESS_TOKEN_REL                      = 'http://apinamespace.org/oauth/access_token';
    public const OAUTH_AUTHORIZE_REL                         = 'http://apinamespace.org/oauth/authorize';
    public static ?AuthorizationServer $authorization_server = null;

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

    /**
     * @throws Exception
     */
    public function onInitializePlugin(): EventResult
    {
        self::$authorization_server = new AuthorizationServer(
            new Repository\Client,
            new Repository\AccessToken,
            new Repository\Scope,
            privateKey: new CryptKey(keyPath: Common::config('oauth2', 'private_key'), passPhrase: Common::config('oauth2', 'private_key_password')),
            encryptionKey: Common::config('oauth2', 'encryption_key'),
            responseType: new ExpandedBearerTokenResponse(),
        );

        self::$authorization_server->enableGrantType(
            new AuthCodeGrant(
                new Repository\AuthCode,
                new Repository\RefreshToken,
                new DateInterval('PT10M'), // ???
            ),
            new DateInterval('PT1H'),
        );
        return Event::next;
    }

    /**
     * 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 Router $r the router that was initialized
     */
    public function onAddRoute(Router $r): EventResult
    {
        $r->connect('oauth2_mastodon_api_apps', '/api/v1/apps', C\Client::class, ['http-methods' => ['POST']]);
        $r->connect('oauth2_client', '/oauth/client', C\Client::class, ['http-methods' => ['POST']]);
        $r->connect('oauth2_authorize', '/oauth/authorize', C\Authorize::class);
        $r->connect('oauth2_token', '/oauth/token', C\Token::class);
        return Event::next;
    }

    public function onEndHostMetaLinks(array &$links): EventResult
    {
        $links[] = new XML_XRD_Element_Link(self::OAUTH_REQUEST_TOKEN_REL, Router::url('oauth2_client', 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;
    }
}
