Refactor calculator into its own module

frontend/Calculator.elm

@@ -0,0 +1,103 @@
+module Calculator exposing (..)
+
+import Html exposing (..)
+import Html.Attributes exposing (..)
+import Html.Events exposing (..)
+
+import NumberInput
+import Select
+
+type Tax = Net | Gross
+
+ctShow ct = case ct of
+  Gross -> "Brutto"
+  Net -> "Netto"
+
+type alias Model =
+  { tax : Select.Model Tax
+  , bundlePrice : NumberInput.Model Float
+  , bundleSize : NumberInput.Model Int
+  }
+
+init bundlePrice = Model
+  (Select.init ctShow ctShow Net [Net, Gross])
+  (NumberInput.fromFloat bundlePrice)
+  (NumberInput.fromInt 1)
+
+getResult model taxGroup =
+  case (NumberInput.get model.bundlePrice, NumberInput.get model.bundleSize) of
+    (Just bundlePrice, Just bundleSize) ->
+      Just <| roundTo 2 <|
+        if Select.get model.tax == Gross then
+          (bundlePrice / toFloat bundleSize) / (1 + taxGroup.percentage)
+        else
+          bundlePrice / toFloat bundleSize
+    _ ->
+      Nothing
+
+
+type Msg
+  = SetTax String
+  | SetBundlePrice String
+  | SetBundleSize String
+
+update msg model = case msg of
+  SetTax key ->
+    { model | tax = Select.update key model.tax }
+  SetBundlePrice str ->
+    { model | bundlePrice = NumberInput.update str model.bundlePrice }
+  SetBundleSize str ->
+    { model | bundleSize = NumberInput.update str model.bundleSize }
+
+view model taxGroup =
+  let
+    mainPart =
+      [ text "("
+      , input
+        [ class "formula-input", placeholder "Gebindepreis"
+        , value <| NumberInput.show model.bundlePrice
+        , onInput SetBundlePrice
+        ]
+        []
+      , text " ÷ "
+      , input
+        [ class "formula-input", placeholder "Gebindegröße"
+        , value <| NumberInput.show model.bundleSize
+        , onInput SetBundleSize
+        ]
+        []
+      , text ") "
+      ]
+    taxPart =
+      [ text " ÷ "
+      , input
+        [ class "formula-input"
+        , disabled True
+        , value <| String.fromFloat <| 1 + taxGroup.percentage
+        ]
+        []
+      ]
+    resultPart =
+      [ text " = "
+      , input
+        [ class "formula-input"
+        , disabled True
+        , value <| Maybe.withDefault "?" <| Maybe.map String.fromFloat <| getResult model taxGroup
+        ]
+        []
+      ]
+  in
+    fieldset []
+      [ legend [] [ text "Preisrechner" ]
+      , div [] <| List.concat <| List.filterMap identity
+        [ Just mainPart
+        , if Select.get model.tax == Gross then Just taxPart else Nothing
+        , Just resultPart
+        ]
+      , div [ class "form-input" ]
+        [ label [ for "calculator-tax" ] [ text "Gebindepreis ist" ]
+        , Select.view SetTax model.tax
+        ]
+      ]
+
+roundTo places x = toFloat (round <| x * 10 ^ places) / 10 ^ places

frontend/Entry.elm

@@ -10,6 +10,7 @@ import Html exposing (..)
 import Html.Attributes exposing (..)
 import Html.Events exposing (..)
 
+import Calculator
 import NumberInput
 import Select
 
@@ -90,35 +91,6 @@ type alias Globals =
   , taxGroups : List TaxGroup
   }
 
-type CalculatorTax = Net | Gross
-
-ctToInt ct = case ct of
-  Gross -> 0
-  Net -> 1
-
-ctShow ct = case ct of
-  Gross -> "Brutto"
-  Net -> "Netto"
-
-type alias CalculatorModel =
-  { tax : Select.Model CalculatorTax
-  , bundlePrice : NumberInput.Model Float
-  , bundleSize : NumberInput.Model Int
-  }
-
-type CalculatorMsg
-  = SetTax String
-  | SetBundlePrice String
-  | SetBundleSize String
-
-updateCalculator msg model = case msg of
-  SetTax key ->
-    { model | tax = Select.update key model.tax }
-  SetBundlePrice str ->
-    { model | bundlePrice = NumberInput.update str model.bundlePrice }
-  SetBundleSize str ->
-    { model | bundleSize = NumberInput.update str model.bundleSize }
-
 type State
   = ItemSearch
     { searchTerm : String
@@ -128,7 +100,7 @@ type State
     { barcode : String
     , name : String
     , salesUnits : NumberInput.Model Int
-    , calculator : CalculatorModel
+    , calculator : Calculator.Model
     , netUnitPrice : NumberInput.Model Float
     , grossUnitPrice : NumberInput.Model Float
     , group : Select.Model Group
@@ -144,7 +116,7 @@ type Msg
   | SetBarcode String
   | SetName String
   | SetSalesUnits String
-  | CalculatorMsg CalculatorMsg
+  | CalculatorMsg Calculator.Msg
   | SetNetUnitPrice String
   | SetGrossUnitPrice String
   | SetGroup String
@@ -179,11 +151,7 @@ updateState msg globals state = case state of
           ( ItemEditor
             { barcode = searchResult.barcode
             , name = searchResult.name
-            , calculator =
-              { tax = Select.init ctShow ctShow Net [Net, Gross]
-              , bundlePrice = NumberInput.fromFloat searchResult.netUnitPrice
-              , bundleSize = NumberInput.fromInt 1
-              }
+            , calculator = Calculator.init searchResult.netUnitPrice
             , netUnitPrice = NumberInput.fromFloat searchResult.netUnitPrice
             , grossUnitPrice = NumberInput.fromFloat
               (suggestedGrossPrice searchResult.netUnitPrice taxGroup.percentage)
@@ -204,7 +172,7 @@ updateState msg globals state = case state of
     SetSalesUnits str ->
       (ItemEditor { model | salesUnits = NumberInput.update str model.salesUnits }, Cmd.none)
     CalculatorMsg msg_ ->
-      (ItemEditor { model | calculator = updateCalculator msg_ model.calculator }, Cmd.none)
+      (ItemEditor { model | calculator = Calculator.update msg_ model.calculator }, Cmd.none)
     SetNetUnitPrice str ->
       ( ItemEditor { model | netUnitPrice = NumberInput.update str model.netUnitPrice }
       , Cmd.none
@@ -269,7 +237,7 @@ view { globals, state } = case state of
           [ label [ for "tax-group" ] [ text "Steuergruppe" ]
           , Select.view SetTaxGroup model.taxGroup
           ]
-        , Html.map CalculatorMsg <| viewCalculator model.calculator (Select.get model.taxGroup)
+        , Html.map CalculatorMsg <| Calculator.view model.calculator (Select.get model.taxGroup)
         , div [ class "form-input" ]
           [ label [ for "net-unit-price" ] [ text "Einkaufspreis (Netto)" ]
           , input
@@ -297,70 +265,8 @@ view { globals, state } = case state of
         ]
       ]
 
-viewCalculator model taxGroup =
-  let
-    mainPart =
-      [ text "("
-      , input
-        [ class "formula-input", placeholder "Gebindepreis"
-        , value <| NumberInput.show model.bundlePrice
-        , onInput SetBundlePrice
-        ]
-        []
-      , text " ÷ "
-      , input
-        [ class "formula-input", placeholder "Gebindegröße"
-        , value <| NumberInput.show model.bundleSize
-        , onInput SetBundleSize
-        ]
-        []
-      , text ") "
-      ]
-    taxPart =
-      [ text " ÷ "
-      , input
-        [ class "formula-input"
-        , disabled True
-        , value <| String.fromFloat <| 1 + taxGroup.percentage
-        ]
-        []
-      ]
-    resultPart =
-      [ text " = "
-      , input
-        [ class "formula-input"
-        , disabled True
-        , value <| Maybe.withDefault "?" <| Maybe.map String.fromFloat <| calculatorResult model taxGroup
-        ]
-        []
-      ]
-  in
-    fieldset []
-      [ legend [] [ text "Preisrechner" ]
-      , div [] <| List.concat <| List.filterMap identity
-        [ Just mainPart
-        , if Select.get model.tax == Gross then Just taxPart else Nothing
-        , Just resultPart
-        ]
-      , div [ class "form-input" ]
-        [ label [ for "calculator-tax" ] [ text "Gebindepreis ist" ]
-        , Select.view SetTax model.tax
-        ]
-      ]
-
-calculatorResult model taxGroup =
-  case (NumberInput.get model.bundlePrice, NumberInput.get model.bundleSize) of
-    (Just bundlePrice, Just bundleSize) ->
-      Just <| roundTo 2 <|
-        if Select.get model.tax == Gross then
-          (bundlePrice / toFloat bundleSize) / (1 + taxGroup.percentage)
-        else
-          bundlePrice / toFloat bundleSize
-    _ ->
-      Nothing
-
 viewSetCalculatedPriceButton model =
-  case calculatorResult model.calculator (Select.get model.taxGroup) of
+  case Calculator.getResult model.calculator (Select.get model.taxGroup) of
     Nothing ->
       button [ disabled True ] [ text "Auf ? setzen" ]
     Just calculatedPrice ->