Ensure those dates and times are working for you!

Globals.php

/**
 * Checks a date/time string to verify it's a valid date/time
 * Supports both Y-m-d and Y-m-d H:i:s
 * @param $dateOrTime
 * @return bool
 */
function isValidDateTime($dateOrTime) {
	if(preg_match("/^(\d{4})-(\d{2})-(\d{2})( ([01][0-9]|2[0-3]):([0-5][0-9]):([0-5][0-9]))?$/", $dateOrTime, $matches)) {
		if(checkdate($matches[2], $matches[3], $matches[1])) {
			return true;
		}
	}

	return false;
}


/**
 * Checks a timestamp to make sure it's valid, integer or string format supported
 * @param $dateOrTime
 * @return bool
 */
function isValidTimestamp($dateOrTime) {
	return ((((string) (int) $dateOrTime === $dateOrTime) && ($dateOrTime <= PHP_INT_MAX) && ($dateOrTime >= ~PHP_INT_MAX))
		|| (is_int($dateOrTime) && $dateOrTime <= PHP_INT_MAX && $dateOrTime >= ~PHP_INT_MAX));
}


/**
 * 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($dateOrTime) && isValidTimestamp($dateOrTime) === false && isValidDateTime($dateOrTime) === true) {
		return date($format, strtotime($dateOrTime)); //ensure we have the correct format

	//maybe it's a unix timestamp
	} elseif(isValidTimestamp($dateOrTime) === true) {
		return date($format, $dateOrTime);

	//rely on the set fallback if set
	} elseif($fallback !== null) {
		return date($format, strtotime($fallback));

	//no idea, return itself
	} else {
		return $dateOrTime;
	}
}


/**
 * 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(isValidTimestamp($dateOrTime) === true) {
		return (int) $dateOrTime; //no need to change

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

	//rely on the set fallback if set
	} elseif($fallback !== null) {
		return (int) $fallback;

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