import Control.Concurrent

    str <- hGetLine handle

    if (linesNumber > 50) || (length str > 450) then

        writeChan chan $ ClientMessage (clientID, ["QUIT", "Protocol violation"])

        else

        if str == "" then do

            writeChan chan $ ClientMessage (clientID, buf)

            yield

            listenLoop handle 0 [] chan clientID

            else

            listenLoop handle (linesNumber + 1) (buf ++ [str]) chan clientID

    listenLoop handle 0 [] chan clientID

        `catch` (\e -> clientOff (show e) >> return ())

    where clientOff msg = writeChan chan $ ClientMessage (clientID, ["QUIT", msg]) -- if the client disconnects, we perform as if it sent QUIT message

    answer <- readChan chan

    doClose <- Exception.handle

        (\(e :: Exception.IOException) -> if isQuit answer then return True else sendQuit e >> return False) $ do

        forM_ answer (hPutStrLn handle)

        hPutStrLn handle ""

        hFlush handle

        return $ isQuit answer

    if doClose then

        Exception.handle (\(_ :: Exception.IOException) -> putStrLn "error on hClose") $ hClose handle

        else

        clientSendLoop handle coreChan chan clientID

    where

        sendQuit e = writeChan coreChan $ ClientMessage (clientID, ["QUIT", show e])

        isQuit ("BYE":xs) = True

        isQuit _ = False