{-
Copyright (C) 2008 John MacFarlane <jgm@berkeley.edu>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-}

{- Auxiliary functions for running shell commands.

   Note:  UTF-8 locale is assumed.
-}

module Gitit.Shell where

import Control.Monad.Trans (liftIO, MonadIO)
import System.Directory (getTemporaryDirectory, removeFile)
import System.Exit (ExitCode)
import System.IO (openTempFile)
import Prelude hiding (readFile)
import System.IO.UTF8
import System.Process (runProcess, waitForProcess)
import Codec.Binary.UTF8.String (encodeString)

-- | Run shell command and return error status, standard output, and error output.
runShellCommand :: FilePath -> Maybe [(String, String)] -> String -> [String] -> IO (ExitCode, String, String)
runShellCommand workingDir environment command optionList = do
  tempPath <- getTemporaryDirectory
  (outputPath, hOut) <- openTempFile tempPath "out"
  (errorPath, hErr) <- openTempFile tempPath "err"
  hProcess <- runProcess command optionList (Just workingDir) environment Nothing (Just hOut) (Just hErr)
  status <- waitForProcess hProcess
  errorOutput <- readFile errorPath
  output <- readFile outputPath
  removeFile errorPath
  removeFile outputPath
  return (status, errorOutput, output)

runProgCommand :: MonadIO m => String -> Maybe [(String, String)] -> String -> String -> [String] -> m (ExitCode, String, String)
runProgCommand workingDir environment prog command args = do
  liftIO $ runShellCommand workingDir environment prog (command : map encodeString args)