script for change absolute link to relative link

script.hs

module Main where

import Control.Concurrent
import Control.Monad
import Data.UUID
import System.Directory
import System.FilePath
import System.Process
import System.Posix.Files 


main :: IO ()
main = do 
  putStrLn "changing absolute link to relative link" 
  cdir <- getCurrentDirectory
  lst <- getDirectoryContents cdir
  mapM_ scriptaction . map fromString $ lst 
  
scriptaction :: Maybe UUID -> IO ()
scriptaction = 
  maybe (return ()) $ \uuid -> do 
    let str = toString uuid 
    odir <- getCurrentDirectory
    let ndir = odir </> str </>  "v0" </> "page"
    doesDirectoryExist ndir >>= \b -> when b $ do
      setCurrentDirectory ndir 
      lst <- return . filter isSVG =<< getDirectoryContents ndir
      putStrLn (str ++ ": " )
      mapM_ lnaction lst
      setCurrentDirectory odir

isSVG :: FilePath -> Bool 
isSVG fp = takeExtension fp  == ".svg"

lnaction :: FilePath -> IO ()
lnaction fp = do
  lfp <- readSymbolicLink fp 
  putStrLn $ fp ++ " -> " ++ lfp
  let fn = takeFileName lfp    
  putStrLn $ "filename = " ++ fn 
  removeLink fp
  threadDelay 100000
  system $ "ln -s ../data/" ++ fn ++ " " ++ fp
  return ()