Compute payers client side rather than server side

1 files changed, 8 insertions, 0 deletions

diff --git a/src/client/elm/Model/Payment.elm b/src/client/elm/Model/Payment.elm
index 31aba1d..80579e2 100644
--- a/src/client/elm/Model/Payment.elm
+++ b/src/client/elm/Model/Payment.elm
@@ -7,6 +7,7 @@ module Model.Payment
   , paymentIdDecoder
   , deletePayment
   , PaymentFrequency(..)
+  , totalPayments
   ) where
 
 import Date exposing (..)
@@ -49,3 +50,10 @@ paymentIdDecoder = Json.int
 
 deletePayment : PaymentId -> Payments -> Payments
 deletePayment paymentId = List.filter (((/=) paymentId) << .id)
+
+totalPayments : (Payment -> Bool) -> UserId -> Payments -> Int
+totalPayments paymentFilter userId payments =
+  payments
+    |> List.filter (\payment -> paymentFilter payment && payment.userId == userId)
+    |> List.map .cost
+    |> List.sum