1 files changed, 43 insertions, 0 deletions
diff --git a/src/client/elm/Sign.elm b/src/client/elm/Sign.elm
new file mode 100644
index 0000000..44f23b8
--- /dev/null
+++ b/src/client/elm/Sign.elm
@@ -0,0 +1,43 @@
+module Sign
+  ( Operation(..)
+  , decodeOperation
+  , toServerCommunication
+  ) where
+
+import Json.Decode as Json
+import Json.Decode exposing (Value, Decoder, (:=))
+import Maybe
+
+import ServerCommunication as SC
+
+type Operation =
+  NoOp
+  | SignIn String
+  | SignOut
+
+decodeOperation : Value -> Operation
+decodeOperation value =
+  Json.decodeValue operationDecoder value
+    |> Result.toMaybe
+    |> Maybe.withDefault NoOp
+
+toServerCommunication : Operation -> SC.Communication
+toServerCommunication operation =
+  case operation of
+    NoOp -> SC.NoCommunication
+    SignIn assertion -> SC.SignIn assertion
+    SignOut -> SC.SignOut
+
+operationDecoder : Decoder Operation
+operationDecoder =
+  ("operation" := Json.string) `Json.andThen` operationDecoderWithTag
+
+operationDecoderWithTag : String -> Decoder Operation
+operationDecoderWithTag operation =
+  case operation of
+    "SignIn" ->
+      Json.map SignIn ("assertion" := Json.string)
+    "SignOut" ->
+      Json.succeed SignOut
+    _ ->
+      Json.succeed NoOp