{-# LANGUAGE LambdaCase #-}
module Hcompta.CLI.Command.Balance where

import           Control.Monad.IO.Class (liftIO)
import           Control.Monad.Trans.Except (runExceptT)
import qualified Data.Either
import qualified Data.List
import           System.Console.GetOpt
                 ( ArgDescr(..)
                 , OptDescr(..)
                 , usageInfo
                 )
import           System.Environment (getProgName)
import           System.Exit (exitWith, ExitCode(..))
import qualified System.IO as IO

import qualified Hcompta.CLI.Args as Args
import qualified Hcompta.CLI.Context as Context
import qualified Hcompta.CLI.Write as Write
import qualified Hcompta.Calc.Balance
import qualified Hcompta.Format.Ledger.Read
-- import qualified Hcompta.Format.Ledger.Write
import qualified Hcompta.Format.Ledger.Journal

data Ctx
 =   Ctx
 { ctx_input :: [FilePath]
 } deriving (Eq, Show)

nil :: Ctx
nil =
	Ctx
	 { ctx_input = []
	 }

usage :: IO String
usage = do
	bin <- getProgName
	return $ unlines $
		[ "SYNTAX "
		, "  "++bin++" balance [option..]"
		, ""
		, usageInfo "OPTIONS" options
		]

options :: Args.Options Ctx
options =
	[ Option "h" ["help"]
	 (NoArg (\_ctx -> do
		usage >>= IO.hPutStr IO.stderr
		exitWith ExitSuccess))
	 "show this help"
	, Option "i" ["input"]
	 (ReqArg (\s ctx -> do
		return $ ctx{ctx_input=s:ctx_input ctx}) "file.ledger")
	 "read data from given file"
	]

run :: Context.Context -> [String] -> IO ()
run context args = do
	(ctx, _) <- Args.parse context usage options (nil, args)
	(flip mapM) (ctx_input ctx) $ \path -> do
		liftIO $ runExceptT $
			Hcompta.Format.Ledger.Read.file path
		>>= \case
		 Left  ko -> return $ Left (path, ko)
		 Right ok -> return $ Right ok
	>>= return . Data.Either.partitionEithers
	>>= \case
	 (kos@(_:_), _oks) ->
		(flip mapM_) kos $ \(_path, ko) ->
			Write.fatal context $ ko
	 ([], journals) -> do
		putStrLn $ show $
			Data.List.foldl
			 (\b j -> Hcompta.Calc.Balance.journal
				 (Hcompta.Format.Ledger.Journal.to_Model j) b)
			 Hcompta.Calc.Balance.nil
			 journals