{- Compile this file with 

ghc -o talk1 -package concurrent -package network Talk1.hs

-}
module Main where

import Concurrent
import Network
import IO
import System (getArgs)
import Char(isControl,ord)

main :: IO ()
main =
  do portNum <- getArgs >>= return . read . head
     s <- listenOn (PortNumber (fromInteger portNum))
     ch<- newChan
     loop s ch

loop :: Socket -> Chan String -> IO ()
loop s ch = 
  do (handle, wh, p) <- accept s
     hSetBuffering handle NoBuffering
     putStrLn ("New connection from "++ wh++ " on "++ show p)
     ch2    <- dupChan ch
     forkIO (newUser handle ch2)
     loop s ch

newUser :: Handle-> Chan String -> IO ()
newUser socket msgch = 
  forkIO read >> write where
    read :: IO ()
    read  = hGetLine socket >>= writeChan msgch >> read
    write :: IO ()
    write = readChan msgch >>= hPutStrLn socket >> write