{-# LANGUAGE ScopedTypeVariables #-}
module Utils (
      outputLn
    , prompt
  ) where

import Control.Monad.IO.Class (MonadIO(..))
import Text.Read (readMaybe)

outputLn :: MonadIO m => String -> m ()
outputLn = liftIO . putStrLn

prompt :: MonadIO m => m () -> m () -> (Int, Int) -> m Int
prompt message onError range@(minVal, maxVal) = do
  message
  mn <- readMaybe <$> liftIO getLine
  case mn of
    Just n | n >= minVal && n <= maxVal -> return n
    _ -> onError >> prompt message onError range