woocommerce_calc_discounts_sequentially option to keep backwards comp…

…atible

includes/admin/settings/class-wc-settings-checkout.php

@@ -68,13 +68,24 @@ public function get_settings() {
 			array(	'title' => __( 'Checkout Process', 'woocommerce' ), 'type' => 'title', 'id' => 'checkout_process_options' ),
 
 			array(
-				'title'    => __( 'Coupons', 'woocommerce' ),
-				'desc'     => __( 'Enable the use of coupons', 'woocommerce' ),
-				'id'       => 'woocommerce_enable_coupons',
-				'default'  => 'yes',
-				'type'     => 'checkbox',
-				'desc_tip' =>  __( 'Coupons can be applied from the cart and checkout pages.', 'woocommerce' ),
-				'autoload' => false
+				'title'         => __( 'Coupons', 'woocommerce' ),
+				'desc'          => __( 'Enable the use of coupons', 'woocommerce' ),
+				'id'            => 'woocommerce_enable_coupons',
+				'default'       => 'yes',
+				'type'          => 'checkbox',
+				'checkboxgroup' => 'start',
+				'desc_tip'      =>  __( 'Coupons can be applied from the cart and checkout pages.', 'woocommerce' ),
+				'autoload'      => false
+			),
+
+			array(
+				'desc'          => __( 'Calculate coupon discounts sequentially', 'woocommerce' ),
+				'id'            => 'woocommerce_calc_discounts_sequentially',
+				'default'       => 'no',
+				'type'          => 'checkbox',
+				'desc_tip'      =>  __( 'When applying multiple coupons, apply the first coupon to the full price and the second coupon to the discounted price and so on.', 'woocommerce' ),
+				'checkboxgroup' => 'end',
+				'autoload'      => false
 			),
 
 			array(

includes/class-wc-cart.php

@@ -1804,7 +1804,7 @@ public function get_discounted_price( $values, $price, $add_totals = false ) {
 
 				foreach ( $this->coupons as $code => $coupon ) {
 					if ( $coupon->is_valid() && ( $coupon->is_valid_for_product( $product, $values ) || $coupon->is_valid_for_cart() ) ) {
-						$discount_amount = $coupon->get_discount_amount( $undiscounted_price, $values, $single = true );
+						$discount_amount = $coupon->get_discount_amount( ( 'yes' === get_option( 'woocommerce_calc_discounts_sequentially', 'no' ) ? $price : $undiscounted_price ), $values, $single = true );
 						$discount_amount = min( $price, $discount_amount );
 						$price           = max( $price - $discount_amount, 0 );
 

includes/updates/woocommerce-update-2.4.php

@@ -0,0 +1,16 @@
+<?php
+/**
+ * Update WC to 2.4.0
+ *
+ * @author 		WooThemes
+ * @category 	Admin
+ * @package 	WooCommerce/Admin/Updates
+ * @version     2.4.0
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+// Maintain the old coupon logic for upgrades
+update_option( 'woocommerce_calc_discounts_sequentially', 'yes' )