module Main where

import FRP.BearRiver
import Control.Monad.Trans.MSF.Reader

type Game = Ball
type Ball = Int

type GameEnv = ReaderT GameSettings

data GameSettings
    = GameSettings
      { leftPlayerPos  :: Int
      , rightPlayerPos :: Int
      }

ballToRight :: Monad m => MSF (GameEnv m) () Ball
ballToRight =
    count >>> arrM addToLeftPlayerPos
    where
      addToLeftPlayerPos =
          (n -> (n +) <$> asks leftPlayerPos)

hitRight :: Monad m => MSF (GameEnv m) Ball Bool
hitRight = arrM (i -> (i >=) <$> asks rightPlayerPos)

module Main where

import FRP.BearRiver
import Control.Monad
import Control.Monad.Trans.MSF.Reader
import Control.Monad.Trans.MSF.Writer

type Game = Ball
type Ball = Int

type GameEnv m =
    WriterT [String] (ReaderT GameSettings m)

data GameSettings
    = GameSettings
      { leftPlayerPos  :: Int
      , rightPlayerPos :: Int
      }

ballToRight :: Monad m => MSF (GameEnv m) () Ball
ballToRight =
    count >>> arrM addLeftPlayerPos >>> arrM checkHitR
    where
      addLeftPlayerPos =
          (n -> (n +) <$> asks leftPlayerPos)
      checkHitR n = do
          rp <- asks rightPlayerPos
when (rp > n) $ tell ["Ball is at " ++ (show n)]