{-|
Module      : $header$
Copyright   : (c) Laurent P René de Cotret, 2020
License     : GNU GPL, version 2 or above
Maintainer  : laurent.decotret@outlook.com
Stability   : internal
Portability : portable

Prelude for renderers, containing some helpful utilities.
-}

module Text.Pandoc.Filter.Plot.Renderers.Prelude (

      module Prelude
    , module Text.Pandoc.Filter.Plot.Types
    , Text
    , st
    , unpack
    , commandSuccess
    , existsOnPath
) where

import           Data.Maybe                    (isJust)
import           Data.Text                     (Text, unpack)
import           System.Exit                   (ExitCode(..))
import           System.Process.Typed          (runProcess, shell, 
                                                setStdout, setStderr, 
                                                nullStream)
import           Text.Shakespeare.Text         (st)

import qualified Turtle                         as Sh

import           Text.Pandoc.Filter.Plot.Types


-- | Check that the supplied command results in
-- an exit code of 0 (i.e. no errors)
commandSuccess :: Text -> IO Bool
commandSuccess s = do
    ec <- runProcess 
            $ setStdout nullStream 
            $ setStderr nullStream 
            $ shell (unpack s)
    return $ ec == ExitSuccess


-- | Checks that an executable is available on path, at all.
existsOnPath :: FilePath -> IO Bool
existsOnPath fp = Sh.which (Sh.fromString fp) >>= fmap isJust . return