relativeTime.php

<?php

function relativeTime(int|float|string $time): string {
	static $minute = 60;
	static $hour = 60 * 60;
	static $day = 24 * 60 * 60;
	static $month = 30 * 24 * 60 * 60;
	static $year = 365 * 24 * 60 * 60;

	if (!is_numeric($time)) {
		$time = strtotime($time);
		if ($time === false) {
			return '[invalid time]';
		}
	}

	$delta = time() - $time;
	$direction = $delta / abs($delta);
	$delta = abs($delta);

	if ($delta < $minute) {
		return $direction > 0 ? 'just now' : 'soon';
	} else if ($delta < $hour) {
		$count = round($delta / $minute);
		$unit = 'minute';
	} else if ($delta < $day) {
		$count = round($delta / $hour);
		$unit = 'hour';
	} else if ($delta < $month) {
		$count = round($delta / $day);
		$unit = 'day';
	} else if ($delta < $year) {
		$count = round($delta / $month);
		$unit = 'month';
	} else {
		$count = round($delta / $year);
		$unit = 'year';
	}

	return $count . ' ' . $unit . ($count == 1 ? '' : 's') . ($direction > 0 ? ' ago' : ' from now');
}