{- | You'll likely want to import this if you're
 using Procex for your shell, though you'll
 likely want to customize your 'promptFunction'
 some time.
-}
module Procex.Shell (promptFunction, initInteractive, cd) where

import System.IO
import System.Posix.Directory
import System.Posix.Env

{- | For some ungodly reason, cd-ing inside ghci won't change the cwd of ghci itself,
 so completion, etc. will always happen from the directory you started ghci in.
 This is a quick hack to work around this by also running changeWorkingDirectory
 "above" the shell.

 Do `:set prompt-function promptFunction` in GHCi
-}
promptFunction :: [String] -> Int -> IO String
promptFunction _modules _line = do
  d <- getEnvDefault "PWD" ""
  changeWorkingDirectory d
  pure $ d <> ": "

-- | You need to run this if you want stdin to work properly inside ghci.
initInteractive :: IO ()
initInteractive = hSetBuffering stdin LineBuffering

{- | This goes hand-in-hand with 'promptFunction'. It is a standard
 'System.Posix.Directory.changeWorkingDirectory', but it sets "PWD" in the environment too.
-}
cd :: String -> IO ()
cd x = changeWorkingDirectory x >> getWorkingDirectory >>= \d -> setEnv "PWD" d True