Correct total calculator to use 8 decimals

CHANGELOG.md

@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- Fixed calculation of order total to ensure 8 decimal places
 - Fixed test for looking for an order with incorrect ID
 - Fixed payment scan to focus only on new transactions
 

src/Order.hs

@@ -188,7 +188,7 @@ updateOrderTotals o =
     (qprice o)
     (newTotal o)
     (if qprice o /= 0
-       then newTotal o / qprice o
+       then roundZec (newTotal o / qprice o)
        else 0)
     (qlines o)
     (qpaid o)
@@ -215,3 +215,7 @@ markOrderPaid i =
   modify
     (select ["_id" =: (read i :: B.ObjectId)] "orders")
     ["$set" =: ["paid" =: True]]
+
+-- | Helper function to round to 8 decimal places
+roundZec :: Double -> Double
+roundZec n = fromInteger (round $ n * (10 ^ 8)) / (10.0 ^^ 8)

src/ZGoBackend.hs

@@ -294,6 +294,10 @@ decodeHexText h = E.decodeUtf8With lenientDecode $ BS.pack $ hexRead h
 encodeHexText :: T.Text -> String
 encodeHexText t = T.unpack . toText . fromBytes $ E.encodeUtf8 t
 
+-- | Helper function to round to 8 decimal places
+roundZec :: Double -> Double
+roundZec n = fromInteger (round $ n * (10 ^ 8)) / (10.0 ^^ 8)
+
 -- Types for the ZGo database documents
 -- | Type to model a country for the database's country list
 data Country =
@@ -788,8 +792,7 @@ scanPayments config pipe = do
     getOrderId re t = do
       let reg = matchAllText re (T.unpack $ zmemo t)
       if not (null reg)
-        then do
-          fst $ head reg ! 1
+        then fst $ head reg ! 1
         else ""
 
 -- | RPC methods