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

import           Control.Monad (Monad(..))
import           Data.Function ((.))
import qualified Data.List as List
import           Data.Monoid ((<>))
import           Data.Functor ((<$>))
import           Data.String (String)
import qualified Data.Text.Lazy as TL
import           System.Console.GetOpt
                  ( getOpt
                  , ArgOrder(..)
                  , OptDescr(..)
                  )
import           System.IO (IO)
import qualified Text.WalderLeijen.ANSI.Text as W

import           Hcompta.CLI.Context (Context)
import qualified Hcompta.CLI.Write as Write

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, []) ->
		(, cmds) <$>
			List.foldl' (>>=) (return ctx) parsers
	 (_, _, errs) ->
		usage c >>=
		Write.fatal c .
			(W.vsep (W.text . TL.pack <$> errs) <>) .
			W.text . TL.pack