WIP: multi code discount constraint

Relates to: #31

code/constraints/MultiCodeDiscountConstraint.php

@@ -0,0 +1,40 @@
+<?php
+
+class MultiCodeDiscountConstraint extends DiscountConstraint{
+
+	private static $has_many = array(
+		"Codes" => "DiscountCode"
+	);
+
+	function updateCMSFields(FieldList $fields){
+		//add datalist for codes
+		//create a datalist component for generating codes
+	}
+
+	public function filter(DataList $list) {
+		//TODO: join with Codes
+
+		return $list;
+	}
+
+	public function check(Discount $discount) {
+		$code = strtolower($this->findCouponCode());
+
+		//TODO: look for code in list
+
+		return true;
+	}
+
+	protected function findCouponCode() {
+		return isset($this->context['CouponCode']) ? $this->context['CouponCode'] : null;
+	}
+
+}
+
+class DiscountCode extends DataObject{
+
+	private static $db = array(
+		"Code" => "Varchar(25)"
+	);
+
+}