From 42a8d40b37f703380fa0f19fc55e2f01baecae42 Mon Sep 17 00:00:00 2001
From: Sylvain <bond.never.die@gmail.com>
Date: Mon, 28 Nov 2016 16:34:39 +0100
Subject: [PATCH] fix partial refund of invoices with cash coupons

---
 app/models/invoice.rb   | 11 ++++++++---
 app/pdfs/pdf/invoice.rb | 14 +++++++++++---
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/app/models/invoice.rb b/app/models/invoice.rb
index bc0e9683f..3facee497 100644
--- a/app/models/invoice.rb
+++ b/app/models/invoice.rb
@@ -138,9 +138,14 @@ class Invoice < ActiveRecord::Base
     # override created_at to compute CA in stats
     avoir.created_at = avoir.avoir_date
     avoir.total = 0
+    # refunds of invoices with cash coupons: we need to ventilate coupons on paid items
+    paid_items = 0
+    refund_items = 0
     invoice_items.each do |ii|
-      if attrs[:invoice_items_ids].include? ii.id
-        raise Exception if ii.invoice_item
+      paid_items += 1 unless ii.amount == 0
+      if attrs[:invoice_items_ids].include? ii.id  # list of items to refund (partial refunds)
+        raise Exception if ii.invoice_item  # cannot refund an item that was already refunded
+        refund_items += 1 unless ii.amount == 0
         avoir_ii = avoir.invoice_items.build(ii.dup.attributes)
         avoir_ii.created_at = avoir.avoir_date
         avoir_ii.invoice_item_id = ii.id
@@ -153,7 +158,7 @@ class Invoice < ActiveRecord::Base
       if avoir.coupon.type == 'percent_off'
         discount = avoir.total * avoir.coupon.percent_off / 100.0
       elsif avoir.coupon.type == 'amount_off'
-        discount = avoir.coupon.amount_off
+        discount = (avoir.coupon.amount_off / paid_items) * refund_items
       else
         raise InvalidCouponError
       end
diff --git a/app/pdfs/pdf/invoice.rb b/app/pdfs/pdf/invoice.rb
index b7720dcd1..6e02e15d2 100644
--- a/app/pdfs/pdf/invoice.rb
+++ b/app/pdfs/pdf/invoice.rb
@@ -141,14 +141,22 @@ module PDF
           total_calc += price
         end
 
-        # subtract the coupon, if any
+        ## subtract the coupon, if any
         unless invoice.coupon_id.nil?
           cp = invoice.coupon
           discount = 0
           if cp.type == 'percent_off'
             discount = total_calc  * cp.percent_off / 100.0
           elsif cp.type == 'amount_off'
-            discount = cp.amount_off / 100.00
+            # refunds of invoices with cash coupons: we need to ventilate coupons on paid items
+            if invoice.is_a?(Avoir)
+              paid_items = invoice.invoice.invoice_items.select{ |ii| ii.amount > 0 }.length
+              refund_items = invoice.invoice_items.select{ |ii| ii.amount > 0 }.length
+
+              discount = ((invoice.coupon.amount_off / paid_items) * refund_items) / 100.0
+            else
+              discount = cp.amount_off / 100.00
+            end
           else
             raise InvalidCouponError
           end
@@ -158,7 +166,7 @@ module PDF
           # discount textual description
           literal_discount = cp.percent_off
           if cp.type == 'amount_off'
-            literal_discount = number_to_currency(discount)
+            literal_discount = number_to_currency(cp.amount_off / 100.00)
           end
 
           # add a row for the coupon