如何用一个接口优雅的实现2个List的翻页加载

const TYPE_LIST1 = 1; 
    const TYPE_LIST2 = 2;
        public static function demoList($userid, $pageCount = 10, $track = '', $select = '*')
    {
        $offsetTrack = 0;
        $typeTrack = 1;
        $more = 1;
        $list1 = [];
        $list2 = [];
        if (!empty($track)) {
            $decodeTrack = explode("|", $track);
            $offsetTrack = intval($decodeTrack[0]);
            $typeTrack = intval($decodeTrack[1]);
        }
        //取list1 或者 list1+list2
        if ($typeTrack == self::TYPE_LIST1) {
            $list1 = self::getList1($userid, $offsetTrack, $pageCount);
            //list1返回的个数比pageCount小 说明数据不足 需要在请求list2的数据
            $list1Count = count($list1);
            if ($list1Count < $pageCount) {
                $typeTrack = self::TYPE_LIST2;
                $offsetTrack = $list1Count;
            } else {
                $track = $offsetTrack + $list1Count . "|" . self::TYPE_LIST1;
                $more = 1;
            }
        }
        //只取list2
        if ($typeTrack == self::TYPE_LIST2) {
            $offset = $offsetTrack;
            $list2 = self::getList2($userid, $pageCount, $offset);
            $more = count($list2) < $pageCount ? 0 : 1;
            $track = $offset + count($list2) . "|" . self::TYPE_LIST2;
        }
        $ret = [
            'track' => $track,
            'more' => $more,
            'list1' => $list1,
            'list2' => $list2,
        ];
        return $ret;
    }
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