-- |
-- Module      :  Main
-- Copyright   :  (c) OleksandrZhabenko 2021
-- License     :  MIT
-- Stability   :  Experimental
-- Maintainer  :  olexandr543@yahoo.com
--
--

{-# OPTIONS_GHC -threaded -rtsopts #-}

{-# LANGUAGE CPP, BangPatterns #-}

module Main where

import Ukrainian.ReverseConcatenations
import System.Environment (getArgs)
import Text.Read (readMaybe)
import Data.Maybe (fromMaybe)
#ifdef __GLASGOW_HASKELL__
#if __GLASGOW_HASKELL__==708
/* code that applies only to GHC 7.8.* */
mconcat = concat
#endif
#endif

main :: IO ()
main = do
  args0 <- getArgs
  let !fstA = fromMaybe 1 (readMaybe (mconcat . take 1 $ args0)::Maybe Int)
      !args
        | fstA == 1 = filter (/= "-i") args0
        | otherwise = filter (/= "-i") . drop 1 $ args0
      !stdinput = any (== "-i") args0 -- If you specify \"-i\" then reads the input text from the stdin otherwise from the file specified instead.
  if stdinput then do
     contents <- getContents
     putStrLn . reverseConcatenations fstA $ contents
  else do
     let !file = concat . take 1 $ args
         !toFile = concat . drop 1 . take 2 $ args
     if null file then putStrLn "No file to read the Ukrainian text is specified. "
     else readFile file >>= return . reverseConcatenations fstA >>= (\ts -> if null toFile then putStrLn ts else writeFile toFile ts)