Add `StateManager` type

src/Internal/Values/StateManager.elm

@@ -0,0 +1,28 @@
+module Internal.Values.StateManager exposing (..)
+
+import Dict exposing (Dict)
+import Internal.Values.Event as Event exposing (Event)
+
+type alias StateManager = Dict (String, String) Event
+
+getStateEvent : String -> String -> StateManager -> Maybe Event
+getStateEvent eventType stateKey =
+    Dict.get ( eventType, stateKey )
+
+updateRoomStateWith : StateManager -> StateManager -> StateManager
+updateRoomStateWith = Dict.union
+
+fromEventList : List Event -> StateManager
+fromEventList =
+    List.filterMap
+        (\event ->
+            event
+                |> Event.stateKey
+                |> Maybe.map
+                    (\key ->
+                        ( ( Event.contentType event, key ), event )
+                    )
+        )
+        >> Dict.fromList
+
+