protected function resortChangelog($changelog)
    {
        // cleanup whitespace
        foreach ($changelog as $i => $line) {
            $changelog[$i] = rtrim($line);
        }
        $changelog = array_filter($changelog);

        $i = 0;
        ArrayHelper::multisort($changelog, function ($line) use (&$i) {
            if (preg_match('/^- (Chg|Enh|Bug|New)( #\d+(, #\d+)*)?: .+/', $line, $m)) {
                $o = ['Bug' => 'C', 'Enh' => 'D', 'Chg' => 'E', 'New' => 'F'];
                return $o[$m[1]] . ' ' . (!empty($m[2]) ? $m[2] : 'AAAA' . $i++);
            }

            return 'B' . $i++;
        }, SORT_ASC, SORT_NATURAL);

        // re-add leading and trailing lines
        array_unshift($changelog, '');
        $changelog[] = '';
        $changelog[] = '';

        return $changelog;
    }