sakura/app/Forum/ForumPerms.php

<?php
/**
 * Holds the forum permission handler.
 * @package Sakura
 */

namespace Sakura\Forum;

use Illuminate\Database\Query\Builder;
use Sakura\DB;
use Sakura\User;
use Traversable;

/**
 * Forum permission handler.
 * @package Sakura
 * @author Julian van de Groep <me@flash.moe>
 */
class ForumPerms
{
    private static $table = 'forum_perms';
    private $forums = [];
    private $user = 0;
    private $ranks = [];
    private $permCache = [];
    private $validCache = [];

    public function __construct(Forum $forum, User $user)
    {
        $this->forums = iterator_to_array($this->getForumIds($forum->id));
        $this->user = $user->id;
        $this->ranks = array_keys($user->ranks);
    }

    public function getForumIds(int $id): Traversable
    {
        // yield the initial id
        yield $id;

        while ($id > 0) {
            $id = DB::table('forums')
                ->where('forum_id', $id)
                ->value('forum_category');

            yield $id;
        }
    }

    public function __get(string $name): bool
    {
        return $this->check($name);
    }

    public function __isset(string $name): bool
    {
        return $this->valid($name);
    }

    public function valid(string $name): bool
    {
        if (!array_key_exists($name, $this->validCache)) {
            $column = 'perm_' . camel_to_snake($name);
            $this->validCache[$name] =  DB::getSchemaBuilder()->hasColumn(static::$table, $column);
        }

        return $this->validCache[$name];
    }

    public function check(string $name): bool
    {
        if (!array_key_exists($name, $this->permCache)) {
            $column = 'perm_' . camel_to_snake($name);

            $result = DB::table(static::$table)
                ->whereIn('forum_id', $this->forums)
                ->where(function (Builder $query) {
                    $query->whereIn('rank_id', $this->ranks)
                        ->orWhere('user_id', $this->user);
                })
                ->whereNotNull($column)
                ->groupBy($column)
                ->min($column);

            $this->permCache[$name] = intval($result) === 1;
        }

        return $this->permCache[$name];
    }
}