module Miscutils where

import IO

import System.IO

import Control.Concurrent

import Control.Concurrent.STM

import Control.Exception (finally)

sendMsg :: Handle -> String -> IO()

sendMsg clientHandle str = finally (return ()) (hPutStrLn clientHandle str >> hFlush clientHandle) -- catch exception when client tries to send to other

sendAll :: [Handle] -> String -> IO[()]

sendAll clientsList str = mapM (\x -> sendMsg x str) clientsList

sendOthers :: [Handle] -> Handle -> String -> IO[()]

sendOthers clientsList clientHandle str = sendAll (filter (/= clientHandle) clientsList) str

extractCmd :: String -> (String, [String])

extractCmd str = if ws == [] then ("", []) else (head ws, tail ws)

		where ws = words str

manipState :: TVar[a] -> ([a] -> [a]) -> IO()

manipState state op =

	atomically $ do

			ls <- readTVar state

			writeTVar state $ op ls