module Check (checkSyntax) where

import Control.Applicative
import Control.Monad
import Data.Char
import Data.List
import Param
import System.Directory
import System.FilePath
import System.IO
import System.Process

----------------------------------------------------------------

checkSyntax :: Options -> String -> IO String
checkSyntax opt file = do
    makeDirectory (outDir opt)
    (_,_,herr,_) <- runInteractiveProcess (ghc opt) ["--make","-Wall",file,"-outputdir","dist/flymake","-o","dist/flymake/a.out"] Nothing Nothing
    refine <$> hGetContents herr
  where
   refine = unfoldLines start . map (dropWhile isSpace) . filter (/="") . lines
   start = (file `isPrefixOf`)

unfoldLines :: (String -> Bool) -> [String] -> String
unfoldLines _ [] = ""
unfoldLines p (x:xs) = x ++ unfold xs
  where
    unfold [] = "\n"
    unfold (l:ls)
      | p l       = ('\n':l) ++ unfold ls
      | otherwise = (' ' :l) ++ unfold ls

----------------------------------------------------------------

makeDirectory :: FilePath -> IO ()
makeDirectory dir = makeDirectoryRecur $ normalise dir
  where
    makeDirectoryRecur "" = return ()
    makeDirectoryRecur cur = do
      exist <- doesDirectoryExist cur
      let par = takeDirectory cur
      unless exist $ do
          makeDirectoryRecur par
          createDirectory cur