{-# LANGUAGE TupleSections #-}
module Hcompta.CLI.Args where

import           Control.Monad (Monad(..), liftM)
import           Data.List (map, foldl')
import           Data.String (String)
import qualified Data.Text.Lazy as TL
import           Prelude (($), (.), IO)
import           System.Console.GetOpt
                  ( getOpt
                  , ArgOrder(..)
                  , OptDescr(..)
                  )

import           Hcompta.CLI.Context (Context)
import qualified Hcompta.CLI.Write as Write
import           Hcompta.Lib.Leijen ((<>))
import qualified Hcompta.Lib.Leijen as W

type Options context
 = [OptDescr (context -> IO context)]

parse
 :: Context
 -> (Context -> IO String)
 -> (Context -> Options c)
 -> (c, [String])
 -> IO (c, [String])
parse c usage options (ctx, args) =
	case getOpt RequireOrder (options c) args of
	 (parsers, cmds, []) -> do
		liftM (, cmds) $
			Data.List.foldl' (>>=) (return ctx) parsers
	 (_, _, errs) -> do
		usage c >>= Write.fatal c .
			(W.vsep (map (W.text . TL.pack) errs) <>) .
			W.text . TL.pack