Function to work out if a coupon is valid .... Returns false if the coupon is invalid and true if the coupon is valid.

gistfile1.php

<?php
	function getIsValid() {
		//we go through all the options that would make it invalid...
		if(! $this->NumberOfTimesCouponCanBeUsed) {
			return false;
		}
		if($this->getUseCount() > $this->NumberOfTimesCouponCanBeUsed) {
			return false;
		}
		$now = strtotime("now");
		$startDate = strtotime($this->StartDate);
		if($now < $startDate) {
			return false;
		}
		//include the end date itself.
		$endDate = strtotime($this->EndDate)+(60*60*24);
		if($now > $endDate) {
			return false;
		}
		return true;
	}