-----------------------------------------------------------------------------
-- |
-- Module      :  Plugins.XMonadLog
-- Copyright   :  (c) Andrea Rossato
-- License     :  BSD-style (see LICENSE)
-- 
-- Maintainer  :  Andrea Rossato <andrea.rossato@unibz.it>
-- Stability   :  unstable
-- Portability :  unportable
--
-- A plugin example for Xmobar, a text based status bar 
--
-----------------------------------------------------------------------------

module Plugins.XMonadLog where

import Prelude hiding (catch)
import Control.Concurrent
import Control.Exception
--import Data.Maybe (fromMaybe)
import System.Environment
import System.Posix.Files (fileExist)
--import System.Posix.IO
import System.IO
import System.Exit

import Plugins

data XLog = XLog
    deriving (Read)

instance Exec XLog where
    run XLog = doXlog
    rate XLog = 10
    alias XLog = "xlog"

doXlog :: IO String
doXlog = do
  h <- getEnv "HOME"
  let fp = h ++ "/.xmonad-status" 
  b <- fileExist h
  if b
     then do 
       var <- newMVar ""
       t <- forkIO (block $ readPipe var fp)
       threadDelay (5 * 100000)
       throwTo t (ExitException ExitSuccess)
       mb <- readMVar var
       return mb -- $ fromMaybe "" mb
     else return []

readPipe :: MVar String -> FilePath -> IO ()
readPipe var fp = do
  catch (unblock go) (const $ return ())
  where go = do
          fh <- openFile fp ReadMode
          str <- hGetLine fh
          modifyMVar_ var (\_ -> return str)
          hClose fh