PHPで日付を中国語に変換する方法

$date_str = $this -> toDateChinese ( date ( 'Ym-d' ));

private function toDateChinese($date)
    {
        $date_arr = explode('-', $date);
        $arr = [];
        foreach ($date_arr as $index => &$val) {
            if (mb_strlen($val) == 4) {
                $arr[] = preg_split(&#39;/(?<!^)(?!$)/u&#39;, $val);
            } else {
                if ($val > 10) {
                    $v[] = 10;
                    $v[] = $val % 10;
                    $arr[] = $v;
                    unset($v);
                } else {
                    $arr[][] = $val;
                }
            }
        }
        $cn = array("一", "二", "三", "四", "五", "六", "七", "八", "九", "十", "零");
        $num = array("1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "0");
        $str_time = &#39;&#39;;
        for ($i = 0; $i < count($arr); $i++) {
            foreach ($arr[$i] as $index => $item) {
                $str_time .= $cn[array_search($item, $num)];
            }
            if ($i == 0) {
                $str_time .= &#39;年&#39;;
            } elseif ($i == 1) {
                $str_time .= &#39;月&#39;;
            } elseif ($i == 2) {
                $str_time .= &#39;日&#39;;
            }
        }
        return $str_time;
    }