module YJTools (
  getLineP
) where

import System.IO             (stdin, stdout, hGetBuffering, hSetBuffering, BufferMode(NoBuffering))
import System.Posix.Terminal (getTerminalAttributes, setTerminalAttributes,
                              TerminalState(Immediately), TerminalMode(EnableEcho), withoutMode)
import System.Posix.IO       (stdOutput)
import Control.Exception     (bracket)
import Control.Monad.Tools   (doWhile)

getLineP :: IO String
getLineP = bracket
  (do
     bi <- hGetBuffering stdin
     bo <- hGetBuffering stdout
     ta <- getTerminalAttributes stdOutput
     setTerminalAttributes stdOutput (withoutMode ta EnableEcho) Immediately
     hSetBuffering stdin NoBuffering
     hSetBuffering stdout NoBuffering
     return (bi, bo, ta))
  (\(bi, bo, ta) -> do
     setTerminalAttributes stdOutput ta Immediately
     hSetBuffering stdin bi
     hSetBuffering stdout bo)
  (const $ do
     doWhile "" $ \s -> do
       c <- getChar
       case c of
         '\n'   -> putChar '\n' >> return (reverse s, False)
	 '\DEL' -> if null s then return ("", True)
	                     else do putChar '\b' >> putChar ' ' >> putChar '\b'
			             return (tail s, True)
         _      -> putChar '*' >> return (c:s, True))