module Main where

import Control.Monad (forever)
import Data.Char (isSpace)
import Data.List (dropWhileEnd)
import System.IO (BufferMode (..), hFlush, hSetBuffering, stdin, stdout)
import System.IO.Error (catchIOError, isEOFError)

main :: IO ()
main = do
  hSetBuffering stdin LineBuffering
  hSetBuffering stdout LineBuffering
  loop `catchIOError` \e -> if isEOFError e then return () else ioError e
  where
    loop = forever $ do
      putStrLn "Please enter your name: "
      putStr "> "
      hFlush stdout
      name <- dropWhileEnd isSpace . dropWhile isSpace <$> getLine
      if null name
        then loop
        else putStrLn $ "Hello, " <> name <> "!\n"