this is a lot of work...

src/Wealth.elm

@@ -0,0 +1,116 @@
+module Wealth exposing (Model, Msg(..), editValue, init, update, view)
+
+import Api.Player exposing (Wealth)
+import Html exposing (..)
+import Html.Attributes exposing (..)
+import Html.Events exposing (..)
+
+
+type Model
+    = View
+    | Edit String
+
+
+init =
+    View
+
+
+view wealth model =
+    div [ class "level-item" ]
+        [ span [ class "icon is-large" ] [ i [ class "fas fa-2x fa-piggy-bank" ] [] ]
+        , span [ class "icon", onClick StartEdit ] [ i [ class "fas fa-tools" ] [] ]
+        ]
+        :: (case model of
+                View ->
+                    viewWealth wealth
+
+                Edit amount ->
+                    viewUpdateWealth amount
+           )
+
+
+viewUpdateWealth amount =
+    [ input
+        [ class "level-item"
+        , class "input"
+        , classList
+            [ ( "is-danger", (not << isValid) amount )
+            , ( "is-success", isValid amount )
+            ]
+        , value amount
+        , onInput AmountChanged
+        ]
+        []
+    , button [ class "level-item button", onClick ConfirmEdit ] [ text "Ok" ]
+    ]
+
+
+viewWealth : Wealth -> List (Html Msg)
+viewWealth wealth =
+    [ showWealthField "pp" <| String.fromInt wealth.pp
+    , showWealthField "gp" <| String.padLeft 2 '0' <| String.fromInt wealth.gp
+    , showWealthField "sp" <| String.fromInt wealth.sp
+    , showWealthField "cp" <| String.fromInt wealth.cp
+    ]
+
+
+showWealthField : String -> String -> Html Msg
+showWealthField name value =
+    div [ class "level-item" ]
+        [ p [ class "has-text-right" ]
+            [ strong [ class "heading is-marginless has-text-white" ] [ text name ]
+            , span [ class <| "is-size-4" ] [ text value ]
+            ]
+        ]
+
+
+type Msg
+    = StartEdit
+    | QuitEdit
+    | AmountChanged String
+    | ConfirmEdit
+
+
+update : Msg -> Model -> ( Model, Maybe Float )
+update msg model =
+    case msg of
+        StartEdit ->
+            ( Edit "0.0", Nothing )
+
+        QuitEdit ->
+            ( View, Nothing )
+
+        AmountChanged newAmount ->
+            ( Edit <| String.replace "," "." newAmount
+            , Nothing
+            )
+
+        ConfirmEdit ->
+            ( View, editValue model )
+
+
+
+-- Checks that the amount is a valid float
+
+
+isValid amount =
+    case String.toFloat amount of
+        Just _ ->
+            True
+
+        Nothing ->
+            False
+
+
+
+-- Returns the edited value as a Float, if it exists
+
+
+editValue : Model -> Maybe Float
+editValue model =
+    case model of
+        View ->
+            Nothing
+
+        Edit value ->
+            String.toFloat value