Calculate a Time Difference Ago (ex: 4 hours ago)

This php function takes a timestamp and returns a detailed string of the time difference expressed in seconds, minutes, hours, days ago, or away if it’s in the future.

Examples

A timestamp 8 hours ago

echo timeDiffString(strtotime('-8 hours'));

Output

8 hours ago

A timestamp 18 hours ago

echo timeDiffString(strtotime('-18 days'));

Output

2 weeks ago

Function

function timeDiffString($timestamp, $detailed=false, $max_detail_levels=8, $precision_level='second', $textDesc=true){

	$now = time();

	//If the difference is positive "ago" - negative "away"
	($timestamp >= $now) ? $action = 'away' : $action = 'ago';

	//Set the periods of time
	$periods = array("second", "minute", "hour", "day", "week", "month", "year", "decade");
	$lengths = array(1, 60, 3600, 86400, 604800, 2630880, 31570560, 315705600);

	$diff = ($action == 'away' ? $timestamp - $now : $now - $timestamp);

	$prec_key = array_search($precision_level,$periods);

	//round diff to the precision_level
	$diff = round(($diff/$lengths[$prec_key]))*$lengths[$prec_key];

	//if the diff is very small, display for ex "just seconds ago"
	if ($diff <= 10) {
		$periodago = max(0,$prec_key-1);
		$agotxt = $periods[$periodago].'s';
		if($textDesc) return "just $agotxt $action";
		return "$agotxt";
	}

	//Go from decades backwards to seconds
	$time = "";
	for ($i = (sizeof($lengths) - 1); $i>0; $i--) {

		//if the difference is greater than the length we are checking... continue
		if($diff > $lengths[$i-1] && ($max_detail_levels > 0)) {

			//65 / 60 = 1.  That means one minute.  130 / 60 = 2. Two minutes.. etc
			$val = floor($diff / $lengths[$i-1]); 
			// add 's' if plural
			$time .= $val ." ". $periods[$i-1].($val > 1 ? 's ' : ' ');
			// subtract the values we just used from the overall diff so we can find the rest of the information
			$diff -= ($val * $lengths[$i-1]);
			//if detailed is turn off (default) only show the first set found, else show all information
			if(!$detailed) { $i = 0; }
			$max_detail_levels--;
		}
	}

	# Basic error checking.
	if($time == "") {
		return "Error-- Unable to calculate time.";
	} else {
		if($textDesc) return $time.$action;
		return $time;
	}
}

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