1 files changed, 27 insertions, 11 deletions
diff --git a/src/Chelleport/AppShell.hs b/src/Chelleport/AppShell.hs
index 0a5bdfe..897af83 100644
--- a/src/Chelleport/AppShell.hs
+++ b/src/Chelleport/AppShell.hs
@@ -14,38 +14,54 @@ data Action act = SysQuit | AppAction act
 
 newtype SysState = SysState {sysExit :: Bool}
 
+type Update state appAction = state -> DrawContext -> appAction -> IO (state, Maybe (Action appAction))
+
+type EventHandler state appAction = state -> SDL.Event -> Maybe (Action appAction)
+
+type View state = state -> DrawContext -> IO ()
+
+type Initializer state = DrawContext -> IO state
+
 setupAppShell ::
-  (DrawContext -> IO state) ->
-  (state -> DrawContext -> appAction -> IO state) ->
-  (state -> SDL.Event -> Maybe (Action appAction)) ->
-  (state -> DrawContext -> IO ()) ->
+  -- forall state appAction.
+  Initializer state ->
+  Update state appAction ->
+  EventHandler state appAction ->
+  View state ->
   IO ()
 setupAppShell initState update eventHandler draw = do
   -- Initialize SDL
   SDL.initializeAll
   TTF.initialize
-
   ctx <- initializeContext
   state <- initState ctx
+
   appLoop ctx (state, SysState {sysExit = False})
 
   shutdownApp ctx
   where
     appLoop drawCtx (state, sysState) = do
-      events <- SDL.pollEvents
-
       SDL.rendererDrawColor (ctxRenderer drawCtx) $= colorBackground
       SDL.clear $ ctxRenderer drawCtx
       draw state drawCtx
       SDL.present $ ctxRenderer drawCtx
 
+      events <- SDL.pollEvents
+
       (newState, newSysState) <- foldM (evaluateEvent drawCtx) (state, sysState) events
-      unless (sysExit newSysState) $ appLoop drawCtx (newState, newSysState)
 
-    evaluateEvent drawCtx stTup event = maybe (pure stTup) (updateState drawCtx stTup) (eventHandler (fst stTup) event)
+      unless (sysExit newSysState) $
+        appLoop drawCtx (newState, newSysState)
+
+    evaluateEvent drawCtx stTup event =
+      maybe (pure stTup) (updateState drawCtx stTup) (eventHandler (fst stTup) event)
+
+    evalUpdateResult _drawCtx sysState (state, Nothing) = pure (state, sysState)
+    evalUpdateResult drawCtx sysState (state, Just action) = updateState drawCtx (state, sysState) action
 
-    updateState _drawCtx (state, sysState) SysQuit = pure (state, sysState {sysExit = True})
-    updateState drawCtx (state, sysState) (AppAction action) = (,sysState) <$> update state drawCtx action
+    updateState _ (state, sysState) SysQuit = pure (state, sysState {sysExit = True})
+    updateState drawCtx (state, sysState) (AppAction action) =
+      update state drawCtx action >>= evalUpdateResult drawCtx sysState
 
 hideWindow :: DrawContext -> IO ()
 hideWindow ctx = SDL.hideWindow (ctxWindow ctx)