-------------------------------------------------------------------------------
-- |
-- Module: Main
-- Copyright: (c) 2008 Marco Túlio Gontijo e Silva <marcot@riseup.net>
-- License: Simple permissive license (see LICENSE)
--
-- Maintainer: Marco Túlio Gontijo e Silva <marcot@riseup.net>
-- Stability: unstable
-- Portability: unportable
--
-- Utility to call iwconfig with open networks.
-------------------------------------------------------------------------------

-- base
import Control.Applicative
import Data.List
import Data.Maybe
import Data.IORef
import GHC.Conc
import System.Environment
import System.Exit

-- mtl
import Control.Monad.Reader

-- process
import System.Cmd

-- HSH
import HSH.Command

-- n-m
import Network.Cell

dhclient :: String -> IORef (Maybe ThreadId) -> IO ()
dhclient interface waitThread
  = do
    exitCode <- system $ "dhclient " ++ interface
    when (exitCode == ExitSuccess)
      $ readIORef waitThread >>= killThread . fromJust

main :: IO ()
main
  = do
    interface <- fromMaybe "wlan0" <$> listToMaybe <$> getArgs
    run ("iwlist " ++ interface ++ " scan")
      >>= iwconfig interface
      . getOpenEssids
      . getCells

iwconfig :: String -> [String] -> IO ()
iwconfig _ [] = return ()
iwconfig interface (essid : rest)
  = do
    iWaitThread <- newIORef Nothing
    dhclientThread
      <- liftIO
      $ system ("iwconfig " ++ interface ++ " essid " ++ essid)
      >> forkIO (dhclient interface iWaitThread)
    waitThread <- forkIO $ wait interface dhclientThread rest
    writeIORef iWaitThread $ Just waitThread

wait :: String -> ThreadId -> [String] -> IO ()
wait interface dhclientThread rest
  = do
    char <- liftIO getChar
    if char == 'n'
      then liftIO (killThread dhclientThread) >> iwconfig interface rest
      else wait interface dhclientThread rest