gistfile1.txt

	public function couponPostAction()
	{
		/**
		 * No reason continue with empty shopping cart
		 */
		if (!$this->_getCart()->getQuote()->getItemsCount()) {
			$this->_goBack();
			return;
		}

		$couponCode = (string) $this->getRequest()->getParam('coupon_code');
		if ($this->getRequest()->getParam('remove') == 1) {
			$couponCode = '';
		}
		$oldCouponCode = $this->_getQuote()->getCouponCode();

		if (!strlen($couponCode) && !strlen($oldCouponCode)) {
			$this->_goBack();
			return;
		}

		try {
			$codeLength = strlen($couponCode);
			$isCodeLengthValid = $codeLength && $codeLength <= Mage_Checkout_Helper_Cart::COUPON_CODE_MAX_LENGTH;

			$this->_getQuote()->getShippingAddress()->setCollectShippingRates(true);
			$this->_getQuote()->setCouponCode($isCodeLengthValid ? $couponCode : '')
				->collectTotals()
				->save();

			if ($codeLength) {
				if ($isCodeLengthValid && $couponCode == $this->_getQuote()->getCouponCode()) {
					$this->_getSession()->addSuccess(
						$this->__('Coupon code "%s" was applied.', Mage::helper('core')->escapeHtml($couponCode))
					);
					$this->_getSession()->setCartCouponCode(strtolower($couponCode));
				} else {
					$this->_getSession()->addError(
						$this->__('Coupon code "%s" is not valid.', Mage::helper('core')->escapeHtml($couponCode))
					);
				}
			} else {
				$this->_getSession()->addSuccess($this->__('Coupon code was canceled.'));
			}

		} catch (Mage_Core_Exception $e) {
			$this->_getSession()->addError($e->getMessage());
		} catch (Exception $e) {
			$this->_getSession()->addError($this->__('Cannot apply the coupon code.'));
			Mage::logException($e);
		}

		$this->_goBack();
	}