php 判断输入日期 的本周，本月，本年的起止日期

public function searchDate（$data）{     if(empty($data['time'])){         $data['time'] = date('Y-m-d H:i:s');     }     switch ($data['time_type']){            case 2:                // 当前周                $time = $data['time'];                $end = date("Y-m-d 23:59:59",strtotime("$time Sunday"));                $start = date("Y-m-d 00:00:00",strtotime("$end - 6 days"));                break;            case 3:                // 当前月                $data['time'] = strtotime($data['time']);                $start = date("Y-m-d H:i:s",mktime(0, 0 , 0,date("m",$data['time']),1,date("Y",$data['time'])));                $end = date("Y-m-d H:i:s",mktime(23,59,59,date("m",$data['time']),date("t",$data['time']),date("Y",$data['time'])));                break;            case 4:                // 当前年                $year = date('Y');                $start = $year."-01-01 00:00:00";                $end = $year."-12-31 23:59:59";                break;            default:                // 当前天                $start = $data['time'] . " 00:00:00";                $end = $data['time'] . " 23:59:59";                break;        }        var_dump($start);echo '<br>';        var_dump($end);die;}

后续会添加 上周下周，上月下月，去年等系列操作