{-# LANGUAGE FlexibleContexts #-}
{- LANGUAGE MultiParamTypeClasses #-}
module Message (
      Connected
    , receive
    , send
  ) where

import Control.Monad.Reader (MonadReader, ReaderT, ask)
import Control.Monad.State (StateT)
import Control.Monad.IO.Class (MonadIO(..))
import Network.WebSockets (Connection, receiveData, sendTextData)
import Data.Aeson (encode, eitherDecode')
import Game (Game)
import qualified Message.Client as Client (Message)
import qualified Message.Server as Server (Message(..))

type Connected a = ReaderT Connection (StateT Game IO) a

{-
class ReaderIO t c where
  f :: t a -> t c
  liftIO :: (a -> IO b) -> a -> t b
-}

send :: (MonadReader Connection t, MonadIO t) => Server.Message -> t ()
send message = do
  connection <- ask
  liftIO $ sendTextData connection $ encode message

receive :: (MonadReader Connection t, MonadIO t) => t Client.Message
receive = do
  connection <- ask
  received <- liftIO $ receiveData connection
  case eitherDecode' received of
    Left message -> send (Server.Error message) >> receive
    Right message -> return message