php relative time

<?php
function ago($tm, $lang = 'fa', $ashtml = true) {
    $local = array('style' => array('fa' => 'style="<a href="http://direction:rtl">direction:rtl</a>;"', 
                                    'en' => 'style="<a href="http://direction:ltr">direction:ltr</a>"'), 
                                    'times' => array(
                                            'fa' => array('ثانیه', 'دقیقه', 'ساعت', 'روز', 'هفته', 'ماه', 'سال', 'دهه'), 
                                           'en' => array('second', 'minute', 'hour', 'day', 'week', 'month', 'year', 'decade')), 
                                           'ago' => array('fa' => 'پیش', 'en' => 'ago'));
    if (intval($tm) > 0) {
        $cur_tm = time();
        $dif = $cur_tm - $tm;
        $lngh = array(1, 60, 3600, 86400, 604800, 2630880, 31570560, 315705600);
        for ($v = sizeof($lngh) - 1; ($v >= 0) && (($no = $dif / $lngh[$v]) <= 1); $v--)
            ; if ($v < 0)
            $v = 0; $_tm = $cur_tm - ($dif % $lngh[$v]);
        $no = floor($no);
        if ($no <> 1 && $lang == 'en')
            $local['times'][$lang][$v] .= 's'; $x = sprintf("%d %s ", $no, $local['times'][$lang][$v]);
        if ($ashtml)
            return " " . $x . ' ' . $local['ago'][$lang] . "";
        else
            return $x . ' ' . $local['ago'][$lang];
    } else {
        return '-';
    }
}