app\models\Beatmapset::rankingETA PHP Method

    public function rankingETA()
    {
        if (!$this->isQualified()) {
            return;
        }
        $queueSize = static::qualified()->where('approved_date', '<', $this->approved_date)->count();
        $days = ceil($queueSize / static::QUALIFICATIONS_PER_DAY);
        return $days > 0 ? Carbon::now()->addDays($days)->startOfDay() : null;
    }