Add text to tell whether date was past/future. "2 days ago" or "2 days from now".

get_date_diff.php

<?php
    /**
     * Get human readable time difference between 2 dates
     *
     * Return difference between 2 dates in year, month, hour, minute or second
     * The $precision caps the number of time units used: for instance if
     * $time1 - $time2 = 3 days, 4 hours, 12 minutes, 5 seconds
     * - with precision = 1 : 3 days
     * - with precision = 2 : 3 days, 4 hours
     * - with precision = 3 : 3 days, 4 hours, 12 minutes
     *
     * From: http://www.if-not-true-then-false.com/2010/php-calculate-real-differences-between-two-dates-or-timestamps/
     *
     * @param mixed $time1 a time (string or timestamp)
     * @param mixed $time2 a time (string or timestamp)
     * @param integer $precision Optional precision
     * @return string time difference
     */
    function get_date_diff( $time1, $time2, $precision = 2 ) {
        // If not numeric then convert timestamps
        if( !is_int( $time1 ) ) {
            $time1 = strtotime( $time1 );
        }
        if( !is_int( $time2 ) ) {
            $time2 = strtotime( $time2 );
        }

        // By default, assume past
        $past = true;

        // If time1 > time2 then swap the 2 values
        if( $time1 > $time2 ) {
            list( $time1, $time2 ) = array( $time2, $time1 );
            $past = false;
        }

        // Set up intervals and diffs arrays
        $intervals = array( 'year', 'month', 'day', 'hour', 'minute', 'second' );
        $diffs = array();

        foreach( $intervals as $interval ) {
            // Create temp time from time1 and interval
            $ttime = strtotime( '+1 ' . $interval, $time1 );
            // Set initial values
            $add = 1;
            $looped = 0;
            // Loop until temp time is smaller than time2
            while ( $time2 >= $ttime ) {
                // Create new temp time from time1 and interval
                $add++;
                $ttime = strtotime( "+" . $add . " " . $interval, $time1 );
                $looped++;
            }

            $time1 = strtotime( "+" . $looped . " " . $interval, $time1 );
            $diffs[ $interval ] = $looped;
        }

        $count = 0;
        $times = array();
        foreach( $diffs as $interval => $value ) {
            // Break if we have needed precission
            if( $count >= $precision ) {
                break;
            }
            // Add value and interval if value is bigger than 0
            if( $value > 0 ) {
                if( $value != 1 ){
                    $interval .= "s";
                }
                // Add value and interval to times array
                $times[] = $value . " " . $interval;
                $count++;
            }
        }

        // Build text for past/future
        if($past == true){
            $suffix = ' ago';
        } else {
            $suffix = ' from now';
        }

        // Return string with times
        return implode( ", ", $times ).$suffix;
    }