Nice relative time (ago)

timeago.php

<?php

protected function nice_time($timestamp) {
    if ( !$timestamp ){
        return '';
    }
    // if no timestamp, do it now
    if ( !is_numeric($timestamp) ){ $timestamp = strtotime( $timestamp ); }
    // $periods = array("second", "minute", "hour", "day", "week", "month", "year", "decade");
    $periods = [$this->_("second"), $this->_("minute"), $this->_("hour"), $this->_("day"), $this->_("week"), $this->_("month"), $this->_("year"), $this->_("decade")];
    $lengths = ["60","60","24","7","4.35","12","10"];
    $tense = $this->_("ago");
    $tense_future = $this->_("in");
    $tense_present = $this->_("just now");
    $now = time();

    $difference = $now - $timestamp;

    if ($difference == 0) {return $tense_present;}
    if ($difference < 0) {$tense = $tense_future;$difference=$difference*-1;/*return 'now';*/}

    for($j = 0; $difference >= $lengths[$j] && $j < count($lengths)-1; $j++) {
        $difference /= $lengths[$j];
    }

    $difference = round($difference);

    if ($difference != 1) {
        $periods[$j].= "s";
    }

    $result = $this->_("{difference} {periods} {tense}");
    $result = str_replace(['{difference}', '{periods}', '{tense}', 'mess'], [$difference, $periods[$j], $tense, 'meses'], $result);

    return $result;
}

protected function _( $string, $vars = [] ){
    $i = 1;
    foreach ($vars as $var) {
        $return = str_replace( '%' . $i, $vars[ $i-1 ], $return );
        $i++;
    }
    return $return;
}