public static function human_time( $time, $current = null ) {
		if ( empty( $current ) ) {
			$current = time();
		}

		$diff = (int) abs( $current - $time );

		if ( $diff < 60 ) {
			$since = sprintf( __( '%ss', 'popup-maker' ), $diff );
		} else if ( $diff < HOUR_IN_SECONDS ) {
			$mins = round( $diff / MINUTE_IN_SECONDS );
			if ( $mins <= 1 ) {
				$mins = 1;
			}
			$since = sprintf( __( '%smin', 'popup-maker' ), $mins );
		} elseif ( $diff < DAY_IN_SECONDS && $diff >= HOUR_IN_SECONDS ) {
			$hours = round( $diff / HOUR_IN_SECONDS );
			if ( $hours <= 1 ) {
				$hours = 1;
			}
			$since = sprintf( __( '%shr', 'popup-maker' ), $hours );
		} elseif ( $diff < WEEK_IN_SECONDS && $diff >= DAY_IN_SECONDS ) {
			$days = round( $diff / DAY_IN_SECONDS );
			if ( $days <= 1 ) {
				$days = 1;
			}
			$since = sprintf( __( '%sd', 'popup-maker' ), $days );
		} elseif ( $diff < MONTH_IN_SECONDS && $diff >= WEEK_IN_SECONDS ) {
			$weeks = round( $diff / WEEK_IN_SECONDS );
			if ( $weeks <= 1 ) {
				$weeks = 1;
			}
			$since = sprintf( __( '%sw', 'popup-maker' ), $weeks );
		} else {
			$since = '';
		}

		return apply_filters( 'pum_human_time_diff', $since, $diff, $time, $current );
	}