protected function calculateEventLength(array $data)
    {
        $start = $this->carbon->copy()->setTimestamp(strtotime($data['start']['date'] . ' ' . $data['start']['time']));

        if (array_key_exists('all_day', $data)) {
            $end = $this->carbon->copy()->setTimestamp(strtotime($data['start']['date'] . ' 23:59:59'));
        } else {
            $end = $this->carbon->copy()->setTimestamp(strtotime($data['start']['date'] . ' ' . $data['end']['time']));
        }

        return $start->diffInSeconds($end);
    }