IRC bot in Haskell

IRC.hs

module Main where

import Network
import System.IO
import Text.Printf
import Data.List
import System.Exit
import System.Time

-- Simple IRC Bot

data Creds = Creds { ircServer :: String
                   , ircPort   :: Int
                   , ircChan   :: String
                   , ircNick   :: String
                   } deriving ( Show ) 

data Message = 
      Ping String 
    | PrivMsg String String String 
    | Join String String 
    | Quit String String
    deriving ( Show )

-- General IRC Utils

getPrivMsg :: Message -> Maybe String
getPrivMsg (PrivMsg x _ _) = Just x
getPrivMsg _ = Nothing

auth :: String -> Int -> String -> String -> Creds
auth s p c n =
    Creds { ircServer=s, ircPort=p, ircChan=c, ircNick=n }  

server = "irc.freenode.org"
port   = 6667
chan   = "#nordic"
nick   = "morpheus"
user   = nick

connectToIRC :: String -> Int -> String -> String ->  IO Handle
connectToIRC server port nick user = do
    h <- connectTo server (PortNumber (fromIntegral port))
    hSetBuffering h NoBuffering
    hPrintf h "NICK %s\n" nick
    hPrintf h "USER %s 0 * :Haskell IRC Bot\n" user
    joinChannel h chan
    return $ h
 
-- Write to the socket handle
write :: Handle -> String -> String -> IO ()
write handle command value = do
    hPrintf handle "%s %s\r\n" command value
    printf         "> %s %s\n" command value

privMsg :: Handle -> String -> IO ()
privMsg h s = write h "PRIVMSG" (chan ++ " :" ++ s)

-- Dispatch function that handles the commands
eval :: Handle -> String -> IO ()
eval h "!!quit" = write h "QUIT" ":Exiting" >> exitWith ExitSuccess
eval h "!!time" = write h "The time is : " " "
eval h _        = return ()

joinChannel :: Handle -> String -> IO ()
joinChannel h channel = do 
    write h "JOIN" channel
 
-- Listen to socket and handle 
listen :: Handle -> IO ()
listen h = forever $ do
    t <- hGetLine h
    putStrLn (init t)
    let s = init t
    if ping s then pong s else eval h (clean s)
  where
    forever a = a >> forever a 
    clean     = drop 1 . dropWhile (/= ':') . drop 1
    ping x    = "PING :" `isPrefixOf` x
    pong x    = write h "PONG" (':' : drop 6 x)

-- Main function
main :: IO()
main = do
    handle <- connectToIRC server port nick nick
    putStrLn msg
    listen handle
    where msg = "Connecting to " ++ server