过滤器有问题

我有课程搜索一切正常，除了，当$r->price它返回所有课程，而不是最后搜索的课程。我需要捕获最后一个“时间”，然后按它过滤价格。 我怎样才能做到这一点？

 $courses = Course::when($r->mainCat, function ($query) use ($mainCat) {
            $courseIdsArray = Direction::whereIn('course_category_id', $mainCat)->pluck('course_id')->toArray();
            return $query->whereIn('id', $courseIdsArray);
        })->when($r->level, function ($query, $level) {
            return $query->where('level', 'like', "%{$level}%");
        })->when($categories && count($categories) > 0, function ($query) use ($categories) {
            return $query->whereIn('course_category_id', $categories);
        })->when($r->price && in_array($r->price, ['more-expensive', 'less-expensive']), function ($query) use ($r) {
            return $query->orderBy('price', $r->price == 'less-expensive' ? 'asc' : 'desc');
        }, function ($query) {
            return $query->statusOn()->order();
        })->paginate(18)->appends($r->query());