Showing exceeding payers

7 files changed, 109 insertions, 8 deletions

diff --git a/src/client/Main.elm b/src/client/Main.elm
index badb450..57e41d4 100644
--- a/src/client/Main.elm
+++ b/src/client/Main.elm
@@ -13,6 +13,7 @@ import Json.Decode as Json
 
 import Model exposing (Model, initialModel)
 import Model.Payment exposing (Payments, paymentsDecoder)
+import Model.Payers exposing (Payers, payersDecoder)
 import Model.Message exposing (messageDecoder)
 import Model.Translations exposing (..)
 
@@ -55,7 +56,7 @@ port initView =
     Just msg ->
       Signal.send actions.address (SignInError msg)
     Nothing ->
-      Task.map2 GoPaymentView getUserName getPayments
+      Task.map3 GoPaymentView getUserName getPayments getPayers
         |> flip Task.andThen (Signal.send actions.address)
         |> flip Task.onError (\_ -> Signal.send actions.address GoSignInView)
 
@@ -65,6 +66,9 @@ getUserName = Http.get messageDecoder "/userName"
 getPayments : Task Http.Error Payments
 getPayments = Http.get paymentsDecoder "/payments"
 
+getPayers : Task Http.Error Payers
+getPayers = Http.get payersDecoder "/payments/total"
+
 ---------------------------------------
 
 port serverCommunicationsPort : Signal (Task Http.RawError ())
diff --git a/src/client/Model/Payers.elm b/src/client/Model/Payers.elm
new file mode 100644
index 0000000..6550eaa
--- /dev/null
+++ b/src/client/Model/Payers.elm
@@ -0,0 +1,57 @@
+module Model.Payers
+  ( Payers
+  , ExceedingPayer
+  , payersDecoder
+  , updatePayers
+  , getOrderedExceedingPayers
+  ) where
+
+import Json.Decode as Json exposing (..)
+import Dict exposing (..)
+import List
+import Maybe
+
+type alias Payers = Dict String Int
+
+payersDecoder : Decoder Payers
+payersDecoder = Json.map Dict.fromList (list payerDecoder)
+
+payerDecoder : Decoder (String, Int)
+payerDecoder =
+  object2 (,)
+    ("userName" := string)
+    ("totalPayment" := int)
+
+updatePayers : Payers -> String -> Int -> Payers
+updatePayers payers userName amountDiff =
+  Dict.update
+    userName
+    (\mbAmount ->
+      case mbAmount of
+        Just amount -> Just (amount + amountDiff)
+        Nothing -> Nothing
+    )
+    payers
+
+type alias ExceedingPayer =
+  { userName : String
+  , amount : Int
+  }
+
+getOrderedExceedingPayers : Payers -> List ExceedingPayer
+getOrderedExceedingPayers payers =
+  let orderedPayers =
+        Dict.toList payers
+          |> List.map (\(userName, amount) -> ExceedingPayer userName amount)
+          |> List.sortBy .amount
+      maybeMinAmount =
+        List.head orderedPayers
+          |> Maybe.map .amount
+  in  case maybeMinAmount of
+        Just minAmount ->
+          orderedPayers
+            |> List.map (\payer -> { payer | amount <- payer.amount - minAmount })
+            |> List.filter (\payer -> payer.amount /= 0)
+            |> List.reverse
+        Nothing ->
+          []
diff --git a/src/client/Model/View/PaymentView.elm b/src/client/Model/View/PaymentView.elm
index 2f2be46..19ad355 100644
--- a/src/client/Model/View/PaymentView.elm
+++ b/src/client/Model/View/PaymentView.elm
@@ -4,6 +4,7 @@ module Model.View.PaymentView
   ) where
 
 import Model.Payment exposing (Payments)
+import Model.Payers exposing (Payers)
 import Model.View.Payment.Add exposing (..)
 import Model.View.Payment.Edition exposing (..)
 
@@ -11,13 +12,15 @@ type alias PaymentView =
   { userName : String
   , add : AddPayment
   , payments : Payments
+  , payers : Payers
   , edition : Maybe Edition
   }
 
-initPaymentView : String -> Payments -> PaymentView
-initPaymentView userName payments =
+initPaymentView : String -> Payments -> Payers -> PaymentView
+initPaymentView userName payments payers =
   { userName = userName
   , add = initAddPayment
   , payments = payments
+  , payers = payers
   , edition = Nothing
   }
diff --git a/src/client/Update.elm b/src/client/Update.elm
index be7538a..df19775 100644
--- a/src/client/Update.elm
+++ b/src/client/Update.elm
@@ -8,6 +8,7 @@ import Time exposing (Time)
 
 import Model exposing (Model)
 import Model.Payment exposing (Payments)
+import Model.Payers exposing (Payers)
 import Model.View as V
 import Model.View.SignInView exposing (..)
 import Model.View.PaymentView exposing (..)
@@ -21,7 +22,7 @@ type Action =
   | GoSignInView
   | SignInError String
   | UpdateSignIn SignInAction
-  | GoPaymentView String Payments
+  | GoPaymentView String Payments Payers
   | UpdatePayment PaymentAction
 
 actions : Signal.Mailbox Action
@@ -36,8 +37,8 @@ updateModel action model =
       { model | currentTime <- time }
     GoSignInView ->
       { model | view <- V.SignInView initSignInView }
-    GoPaymentView userName payments ->
-      { model | view <- V.PaymentView (initPaymentView userName payments) }
+    GoPaymentView userName payments payers ->
+      { model | view <- V.PaymentView (initPaymentView userName payments payers) }
     SignInError msg ->
       let signInView = { initSignInView | result <- Just (Err msg) }
       in  { model | view <- V.SignInView signInView }
diff --git a/src/client/Update/Payment.elm b/src/client/Update/Payment.elm
index 67331d6..53dc08a 100644
--- a/src/client/Update/Payment.elm
+++ b/src/client/Update/Payment.elm
@@ -4,9 +4,11 @@ module Update.Payment
   ) where
 
 import Date
+import Dict
 
 import Model exposing (Model)
 import Model.Payment exposing (..)
+import Model.Payers exposing (..)
 import Model.View.PaymentView exposing (..)
 import Model.View.Payment.Add exposing (..)
 
@@ -36,8 +38,16 @@ updatePayment model action paymentView =
       in  { paymentView
           | payments <- addPayment paymentView.payments (id, payment)
           , add <- initAddPayment
+          , payers <- updatePayers paymentView.payers payment.userName payment.cost
           }
     ToggleEdit id ->
       { paymentView | edition <- if paymentView.edition == Just id then Nothing else Just id }
     Remove id ->
-      { paymentView | payments <- removePayment paymentView.payments id }
+      case Dict.get id paymentView.payments of
+        Just payment ->
+          { paymentView
+          | payments <- removePayment paymentView.payments id
+          , payers <- updatePayers paymentView.payers payment.userName -payment.cost
+          }
+        Nothing ->
+          paymentView
diff --git a/src/client/View/Payments.elm b/src/client/View/Payments.elm
index 29ab481..03886f8 100644
--- a/src/client/View/Payments.elm
+++ b/src/client/View/Payments.elm
@@ -9,6 +9,7 @@ import Model exposing (Model)
 import Model.Payment exposing (Payments)
 import Model.View.PaymentView exposing (PaymentView)
 
+import View.Payments.ExceedingPayer exposing (exceedingPayers)
 import View.Payments.Add exposing (addPayment)
 import View.Payments.Table exposing (paymentsTable)
 
@@ -16,6 +17,7 @@ renderPayments : Model -> PaymentView -> Html
 renderPayments model paymentView =
   div
     [ class "payments" ]
-    [ addPayment model paymentView.add
+    [ exceedingPayers paymentView
+    , addPayment model paymentView.add
     , paymentsTable model paymentView
     ]
diff --git a/src/client/View/Payments/ExceedingPayer.elm b/src/client/View/Payments/ExceedingPayer.elm
new file mode 100644
index 0000000..cea8d66
--- /dev/null
+++ b/src/client/View/Payments/ExceedingPayer.elm
@@ -0,0 +1,24 @@
+module View.Payments.ExceedingPayer
+  ( exceedingPayers
+  ) where
+
+import Html exposing (..)
+import Html.Attributes exposing (..)
+import List
+
+import Model.Payers exposing (..)
+import Model.View.PaymentView exposing (PaymentView)
+
+exceedingPayers : PaymentView -> Html
+exceedingPayers paymentView =
+  div
+    [ class "exceedingPayers" ]
+    (List.map exceedingPayer (getOrderedExceedingPayers paymentView.payers))
+
+exceedingPayer : ExceedingPayer -> Html
+exceedingPayer payer =
+  div
+    [ class "exceedingPayer" ]
+    [ span [ class "userName" ] [ text payer.userName ]
+    , span [ class "amount" ] [ text ("+ " ++ (toString payer.amount)) ]
+    ]