Globals.php

/**
 * Ensures that the value passed is in datetime format
 * @param null $dateOrTime
 * @param string $format
 * @param string $fallback
 * @return null|string
 */
function ensureDateTime($dateOrTime = null, $format = "c", $fallback = null) {
	if(!$dateOrTime && !$fallback)
		return null;

	//is it a normal datetime string
	if(is_string($dateOrTime) && strtotime($dateOrTime) !== false) {
		return date($format, strtotime($dateOrTime)); //ensure we have the correct format

	//maybe it's a unix timestamp
	} elseif(is_int($dateOrTime) && ($dateOrTime <= PHP_INT_MAX && $dateOrTime >= ~PHP_INT_MAX)) {
		return date($format, $dateOrTime);

	//or possibly a unix timestamp as a string
	} elseif(is_string($dateOrTime) && strtotime($dateOrTime) === false) {
		$dateOrTime = (int) $dateOrTime;
		return (date($format, $dateOrTime) !== false) ? date($format, $dateOrTime) : null;

	//no idea
	} else {
		return date($format, strtotime($fallback));
	}
}


/**
 * Ensures that the passed value is a valid unix timestamp
 * @param null $dateOrTime
 * @param int $fallback
 * @return int|null
 */
function ensureTimestamp($dateOrTime = null, $fallback = null) {
	if(!$dateOrTime && !$fallback)
		return null;

	//maybe it's a unix timestamp
	if(is_int($dateOrTime) && ($dateOrTime <= PHP_INT_MAX && $dateOrTime >= ~PHP_INT_MAX)) {
		return $dateOrTime; //no need to change

	//maybe it's datetime string
	} elseif(is_string($dateOrTime) && strtotime($dateOrTime) !== false) {
		return strtotime($dateOrTime);

	//or possibly a unix timestamp as a string
	} elseif(is_string($dateOrTime) && strtotime($dateOrTime) === false) {
		return (int) $dateOrTime;

	//no idea
	} else {
		return $fallback;
	}
}