PHP友好的时间显示函数

function format_date($time){
    $t = time-$time;
    $f = array(
        '31536000'=>'年前',
        '2592000'=>'个月前',
        '604800'=>'星期前',
        '86400'=>'天前',
        '3600'=>'小时前',
        '60'=>'分钟前',
        '1'=>'刚刚',
    );
    
    foreach($if as $k=>$v){
        if(0 != $c = floor($t/(int)$k)){
            return $v;
        }
    }
}