module Hcompta.CLI.Env where

import           Control.Exception (tryJust)
import           Control.Monad (Monad(..), guard)
import           Data.Either (Either(..))
import           Prelude (($), (.), IO)
import           System.Environment as Env (getEnv)
import           System.IO (FilePath)
import           System.IO.Error (isDoesNotExistError)

import qualified Hcompta.CLI.Context as C
import qualified Hcompta.CLI.Lang as Lang
import qualified Hcompta.CLI.Write as Write

-- | Return 'FilePath's containing 'Hcompta.Format.JCC.Journal's:
--
-- * either those given if any,
-- * or the one in HCOMPTA_JOURNAL environment variable if any,
paths :: C.Context -> [FilePath] -> IO [FilePath]
paths c [] = do
	tryJust (guard . isDoesNotExistError) $ Env.getEnv "HCOMPTA_JOURNAL"
	>>= \x -> case x of
	 Right ok -> return [ok]
	 Left  _ko -> Write.fatal c Lang.Error_No_input_file_given
paths _c ps = return ps