module Run (runCommand) where

import System.Process (runInteractiveCommand,waitForProcess)

import Control.Concurrent (forkIO)

import Control.Concurrent.MVar (newEmptyMVar,takeMVar,putMVar)

import Control.Exception (finally)

import System.IO (stderr,hGetContents,hPutStr,hPutStrLn)

import System.Exit (ExitCode(..))

runCommand ::  String -> String -> Bool -> IO (String,Bool)
runCommand cmd input silent = do
    (inp,out,err,pid) <- runInteractiveCommand cmd
    let get h = do
            mvar <- newEmptyMVar
            let put xs = seq (length xs) (putMVar mvar xs)
            forkIO $ finally (hGetContents h >>= put) (put [])
            takeMVar mvar            
    if null input then return () else hPutStr inp input
    output <- get out
    errmsg <- get err
    exit   <- waitForProcess pid
    case exit of
        ExitSuccess -> return (output,True)
        ExitFailure _ -> do
            if silent then return () else hPutStrLn stderr errmsg
            return (errmsg,False)