Modify Game's export function to edit JSON content

hanafuda-webapp.cabal

@@ -1,7 +1,7 @@
 -- Initial hanafudapi.cabal generated by cabal init.  For further 
 -- documentation, see http://haskell.org/cabal/users-guide/
 
-name:                hanafudapi
+name:                hanafuda-webapp
 version:             0.1.1.0
 synopsis:            A webapp for the Haskell hanafuda library
 -- description:         
@@ -35,6 +35,7 @@ executable hanafudapi
   build-depends:       base >=4.10 && <4.11
                      , bytestring
                      , containers
+                     , unordered-containers
                      , hanafuda >= 0.3.0
                      , http-types
                      , aeson

src/Game.hs

@@ -4,6 +4,7 @@
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE GeneralizedNewtypeDeriving #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE OverloadedStrings #-}
 module Game (
       Key
     , View
@@ -15,7 +16,8 @@ module Game (
 
 import Data.Text (pack)
 import Data.Map (mapWithKey)
-import Data.Aeson (FromJSON(..), ToJSON(..), ToJSON1(..), ToJSONKey(..), genericParseJSON, genericToEncoding, genericLiftToEncoding, toEncoding1, toJSON1)
+import Data.HashMap.Strict (insert)
+import Data.Aeson (FromJSON(..), ToJSON(..), ToJSON1(..), ToJSONKey(..), Value(..), genericParseJSON, genericToEncoding, genericLiftToEncoding, toEncoding1, toJSON1)
 import Data.Aeson.Types (toJSONKeyText)
 import qualified JSON (defaultOptions, singleLCField)
 import qualified Data (Key)
@@ -90,16 +92,16 @@ new :: Player.Key -> Player.Key -> IO T
 new p1 p2 = do
   Hanafuda.KoiKoi.new [p1, p2] Hanafuda.KoiKoi.WholeYear
 
-export :: Player.Key -> T -> T
+export :: Player.Key -> T -> Value
-export key on = on {
+export key on = Object $ insert "deck" (toJSON $ length $ Hanafuda.KoiKoi.deck on) $ ast
-      Hanafuda.KoiKoi.deck = []
-    , Hanafuda.KoiKoi.players = Hanafuda.Player.Players $ mapWithKey maskOpponentsHand unfiltered
-  }
   where
     Hanafuda.Player.Players unfiltered = Hanafuda.KoiKoi.players on
     maskOpponentsHand k player
       | k == key = player
       | otherwise = player {Hanafuda.Player.hand = Hanafuda.empty}
+    Object ast = toJSON $ on {
+        Hanafuda.KoiKoi.players = Hanafuda.Player.Players $ mapWithKey maskOpponentsHand unfiltered
+      }
 
 play :: Player.Key -> Hanafuda.KoiKoi.Move -> T -> IO (Hanafuda.KoiKoi.Game Player.Key)
 play key move on