builder.hs

module Main where

import Control.Monad (forM_)
import System.FilePath (isExtensionOf)
import qualified Data.ByteString as B
import qualified Data.ByteString.Builder as U
import System.Directory (listDirectory)
import DataSize

data FixState
  = Start
  | Backslash
  deriving (Show, Eq)

fixFile :: FilePath -> IO ()
fixFile file = do
    putStrLn $ "fixing " <> file
    contents <- B.readFile file
    let (fixedContents, _) = B.foldl' op (mempty, Start) contents
    U.writeFile file fixedContents
  where
    bs = 0x5c
    op (contents, Start) !c = (contents <> U.word8 c, if c == bs then Backslash else Start)
    op (contents, Backslash) !c
      | c == bs = (contents <> U.word8 bs, Start)
      | otherwise = (contents <> U.word8 bs <> U.word8 c, Start)

fixSlashes :: FilePath -> IO ()
fixSlashes directory = do
    files <- listDirectory directory
    let textFiles = filter (isExtensionOf "txt") files
    forM_ (inData <$> textFiles) fixFile
  where
    inData file = directory <> "/" <> file

main :: IO ()
main = do
  fixFile "example.txt"