PHP通过当前日期判断是当月的第几周

$now_week_num = self::current_week(strtotime($date));

public static function current_week($date)
{
    $week = self::get_week_block($date, $offset = 1);
    $wk_day = date('w', strtotime(date('Y-m-1 00:00:00', $date))) ?: 7; //今天周几
    $day = date('d', $date) - (8 - $wk_day); //今天几号
    $weekof = $day <= 0 ? 1 : ceil($day / 7) + 1; //计算是第几个星期
    if ($offset) {
        $week[0] = date('Y-m-d', max(strtotime(date('Y-m-1 00:00:00', $date)), $week[0]));
        $week[1] = date('Y-m-d', min(strtotime(date('Y-m-' . date('t', $date) . ' 23:59:59', $date)), $week[1]));
    } else {
        $week[0] = date('Y-m-d', $week[0]);
        $week[1] = date('Y-m-d', $week[1]);
    }
    return ['week' => $week, 'weekof' => $weekof];
}

public static function get_week_block($sdefaultDate = false, $first = 1)
{
    //当前日期
    //$first =1 表示每周星期一为开始日期 0表示每周日为开始日期
    if (!$sdefaultDate) $sdefaultDate = time();
    if (is_numeric($sdefaultDate)) $sdefaultDate = date('Y-m-d', $sdefaultDate);
    //获取当前周的第几天 周日是 0 周一到周六是 1 - 6
    $w = date('w', strtotime($sdefaultDate));
    //获取本周开始日期，如果$w是0，则表示周日，减去 6 天
    $week_start = date('Y-m-d', strtotime("$sdefaultDate -" . ($w ? $w - $first : 6) . ' days'));
    //本周结束日期
    $week_end = date('Y-m-d', strtotime("$week_start +6 days"));

    return array(strtotime($week_start . ' 00:00:00'), strtotime($week_end . ' 23:59:59'));
}