-----------------------------------------------------------------------------
-- |
-- Module      :  XMonadContrib.Run
-- Copyright   :  (C) 2007 Spencer Janssen, Andrea Rossato, glasser@mit.edu
-- License     :  BSD-style (see LICENSE)
-- 
-- Maintainer  :  Christian Thiemann <mail@christian-thiemann.de>
-- Stability   :  unstable
-- Portability :  unportable
--
-- This modules provides several commands to run an external process.
-- It is composed of functions formerly defined in XMonadContrib.Dmenu (by
-- Spenver Jannsen), XMonadContrib.Dzen (by glasser@mit.edu) and
-- XMonadContrib.RunInXTerm (by Andrea Rossato).
--
-----------------------------------------------------------------------------

module XMonadContrib.Run (
                          -- * Usage
                          -- $usage
                          runInXTerm,
                          runProcessWithInput,
                          runProcessWithInputAndWait,
                          seconds
                         ) where

import XMonad
import Control.Concurrent (threadDelay)
import Control.Monad.State
import System.Environment
import System.Exit
import System.IO
import System.Posix.Process (forkProcess, getProcessStatus, createSession)
import System.Process


-- $usage
-- For an example usage of runInXTerm see XMonadContrib.SshPrompt
--
-- For an example usage of runProcessWithInput see
-- XMonadContrib.{DirectoryPrompt,Dmenu,ShellPrompt,WmiiActions,WorkspaceDir}
--
-- For an example usage of runProcessWithInputAndWait see XMonadContrib.Dzen

-- | Returns Just output if the command succeeded, and Nothing if it didn't.
-- This corresponds to dmenu's notion of exit code 1 for a cancelled invocation.
runProcessWithInput :: FilePath -> [String] -> String -> IO String
runProcessWithInput cmd args input = do
    (pin, pout, perr, ph) <- runInteractiveProcess cmd args Nothing Nothing
    hPutStr pin input
    hClose pin
    output <- hGetContents pout
    when (output==output) $ return ()
    hClose pout
    hClose perr
    waitForProcess ph
    return output

-- wait is in us
runProcessWithInputAndWait :: FilePath -> [String] -> String -> Int -> IO ()
runProcessWithInputAndWait cmd args input timeout = do
    pid <- forkProcess $ do
       forkProcess $ do -- double fork it over to init
         createSession
         (pin, pout, perr, ph) <- runInteractiveProcess cmd args Nothing Nothing
         hPutStr pin input
         hFlush pin
         threadDelay timeout
         hClose pin
         --     output <- hGetContents pout
         --     when (output==output) $ return ()
         hClose pout
         hClose perr
         waitForProcess ph
         return ()
       exitWith ExitSuccess
       return ()
    getProcessStatus True False pid
    return ()

runInXTerm :: String -> X ()
runInXTerm com = do
  c <- io $ catch (getEnv "XTERMCMD") (const $ return "xterm")
  spawn ("exec " ++ c ++ " -e " ++ com)

-- | Multiplies by ONE MILLION, for use with runProcessWithInputAndWait.
-- Use like:
-- > (5.5 `seconds`)
seconds :: Rational -> Int
seconds = fromEnum . (* 1000000)