<?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/>.
// }}}

/**
 * Base class for feed controllers
 *
 * @package  GNUsocial
 * @category Controller
 *
 * @author    Hugo Sales <hugo@hsal.es>
 * @copyright 2021 Free Software Foundation, Inc http://www.fsf.org
 * @license   https://www.gnu.org/licenses/agpl.html GNU AGPL v3 or later
 */

namespace Component\Feed\Util;

use App\Core\Controller;
use App\Core\Event;
use function App\Core\I18n\_m;
use App\Entity\Actor;
use App\Entity\Note;
use App\Util\Common;
use App\Util\Exception\ClientException;
use App\Util\Formatting;
use Functional as F;

abstract class FeedController extends Controller
{
    /**
     * Post-processing of the result of a feed controller, to remove any
     * notes or actors the user specified, as well as format the raw
     * list of notes into a usable format
     */
    protected function postProcess(array $result): array
    {
        $actor = Common::actor();

        if (\array_key_exists('notes', $result)) {
            $notes = $result['notes'];
            self::enforceScope($notes, $actor);
            $types = $this->string('types');
            if (!\is_null($types)) {
                self::filterNoteType($notes, $types);
            }
            Event::handle('FilterNoteList', [$actor, &$notes, $result['request']]);
            Event::handle('FormatNoteList', [$notes, &$result['notes']]);
        }

        return $result;
    }

    private static function filterNoteType(array &$notes, string $types): void
    {
        $types = explode(',', $types);
        $types = [
            ...$types,
            // Add any missing types as a negation
            ...array_diff(['!media', '!link', '!text', '!tags'], F\map($types, fn ($t) => $t[0] === '!' ? $t : '!' . $t)),
        ];

        $notes = F\select($notes, function (Note $note) use ($types) {
            $include = false;
            foreach ($types as $type) {
                $is_negate = $type[0] === '!';
                $type = Formatting::removePrefix($type, '!');
                $ret = (function () use ($note, $type) {
                    switch ($type) {
                    case 'media':
                        return !empty($note->getAttachments());
                    case 'link':
                        return !empty($note->getLinks());
                    case 'text':
                        return !\is_null($note->getContent());
                    case 'tags':
                        return !empty($note->getTags());
                    default:
                        throw new ClientException(_m('Unknown note type requested ({type})', ['{type}' => $type]));
                    }
                })();
                if ($is_negate && $ret) {
                    return false;
                }
                $include = $include || $ret;
            }
            return $include;
        });
    }

    private static function enforceScope(array &$notes, ?Actor $actor): void
    {
        $notes = F\select($notes, fn (Note $n) => $n->isVisibleTo($actor));
    }
}