time.php

<?php

/*
 * These functions are to mess with time.
 */

// Calculate how long ago something was:
function get_time_ago( $time_stamp ) {
	$time_difference = strtotime('now') - $time_stamp;

	if ( $time_difference >= 60 * 60 * 24 * 365.242199 ) {
		/*
		 * 60 seconds/minute * 60 minutes/hour * 24 hours/day * 365.242199 days/year
		 * This means that the time difference is 1 year or more
		 */
		return get_time_ago_string( $time_stamp, 60 * 60 * 24 * 365.242199, 'year' );
	} elseif ($time_difference >= 60 * 60 * 24 * 30.4368499) {
		/*
		 * 60 seconds/minute * 60 minutes/hour * 24 hours/day * 30.4368499 days/month
		 * This means that the time difference is 1 month or more
		 */
		return get_time_ago_string( $time_stamp, 60 * 60 * 24 * 30.4368499, 'month' );
	} elseif ( $time_difference >= 60 * 60 * 24 * 7 ) {
		/*
		 * 60 seconds/minute * 60 minutes/hour * 24 hours/day * 7 days/week
		 * This means that the time difference is 1 week or more
		 */
		return get_time_ago_string( $time_stamp, 60 * 60 * 24 * 7, 'week' );
	} elseif ( $time_difference >= 60 * 60 * 24 ) {
		/*
		 * 60 seconds/minute * 60 minutes/hour * 24 hours/day
		 * This means that the time difference is 1 day or more
		 */
		return get_time_ago_string( $time_stamp, 60 * 60 * 24, 'day' );
	} elseif ( $time_difference >= 60 * 60 ) {
		/*
		 * 60 seconds/minute * 60 minutes/hour
		 * This means that the time difference is 1 hour or more
		 */
		return get_time_ago_string($time_stamp, 60 * 60, 'hour');
	} else {
		/*
		 * 60 seconds/minute
		 * This means that the time difference is a matter of minutes
		 */
		return get_time_ago_string($time_stamp, 60, 'minute');
	}
}

function get_time_ago_string( $time_stamp, $divisor, $time_unit ) {
	$time_difference = strtotime( 'now' ) - $time_stamp;
	$time_units      = floor( $time_difference / $divisor );

	settype( $time_units, 'string' );

	if ( $time_units === '0') {
		return 'less than 1 ' . $time_unit;
	} elseif ( $time_units === '1' ) {
		return '1 ' . $time_unit;
	} else {
		/*
		 * More than "1" $time_unit. This is the "plural" message.
		 */
		return $time_units . ' ' . $time_unit . 's';
	}
}