{-# LANGUAGE OverloadedStrings #-}
{-
Copyright (C) 2010-2017 John MacFarlane <jgm@berkeley.edu>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
-}

{- |
   Module      : Text.Pandoc.UTF8
   Copyright   : Copyright (C) 2010-2017 John MacFarlane
   License     : GNU GPL, version 2 or above

   Maintainer  : John MacFarlane <jgm@berkeley.edu>
   Stability   : alpha
   Portability : portable

UTF-8 aware string IO functions that will work with GHC 6.10, 6.12, or 7.
-}
module Text.Pandoc.UTF8 ( readFile
                        , getContents
                        , writeFileWith
                        , writeFile
                        , putStrWith
                        , putStr
                        , putStrLnWith
                        , putStrLn
                        , hPutStrWith
                        , hPutStr
                        , hPutStrLnWith
                        , hPutStrLn
                        , hGetContents
                        , toString
                        , toText
                        , fromString
                        , fromText
                        , toStringLazy
                        , fromTextLazy
                        , toTextLazy
                        , fromStringLazy
                        , encodePath
                        , decodeArg
                        )

where

import qualified Data.ByteString.Char8 as B
import qualified Data.ByteString.Lazy.Char8 as BL
import qualified Data.Text as T
import qualified Data.Text.Encoding as T
import qualified Data.Text.Lazy as TL
import qualified Data.Text.Lazy.Encoding as TL
import Prelude hiding (getContents, putStr, putStrLn, readFile, writeFile)
import System.IO hiding (getContents, hGetContents, hPutStr, hPutStrLn, putStr,
                  putStrLn, readFile, writeFile)
import qualified System.IO as IO

readFile :: FilePath -> IO String
readFile f = do
  h <- openFile (encodePath f) ReadMode
  hGetContents h

getContents :: IO String
getContents = hGetContents stdin

writeFileWith :: Newline -> FilePath -> String -> IO ()
writeFileWith eol f s =
  withFile (encodePath f) WriteMode $ \h -> hPutStrWith eol h s

writeFile :: FilePath -> String -> IO ()
writeFile = writeFileWith nativeNewline

putStrWith :: Newline -> String -> IO ()
putStrWith eol s = hPutStrWith eol stdout s

putStr :: String -> IO ()
putStr = putStrWith nativeNewline

putStrLnWith :: Newline -> String -> IO ()
putStrLnWith eol s = hPutStrLnWith eol stdout s

putStrLn :: String -> IO ()
putStrLn = putStrLnWith nativeNewline

hPutStrWith :: Newline -> Handle -> String -> IO ()
hPutStrWith eol h s =
  hSetNewlineMode h (NewlineMode eol eol) >>
  hSetEncoding h utf8 >> IO.hPutStr h s

hPutStr :: Handle -> String -> IO ()
hPutStr = hPutStrWith nativeNewline

hPutStrLnWith :: Newline -> Handle -> String -> IO ()
hPutStrLnWith eol h s =
  hSetNewlineMode h (NewlineMode eol eol) >>
  hSetEncoding h utf8 >> IO.hPutStrLn h s

hPutStrLn :: Handle -> String -> IO ()
hPutStrLn = hPutStrLnWith nativeNewline

hGetContents :: Handle -> IO String
hGetContents = fmap toString . B.hGetContents
-- hGetContents h = hSetEncoding h utf8_bom
--                   >> hSetNewlineMode h universalNewlineMode
--                   >> IO.hGetContents h

-- | Convert UTF8-encoded ByteString to Text, also
-- removing '\r' characters.
toText :: B.ByteString -> T.Text
toText = T.decodeUtf8 . filterCRs . dropBOM
  where dropBOM bs =
         if "\xEF\xBB\xBF" `B.isPrefixOf` bs
            then B.drop 3 bs
            else bs
        filterCRs = B.filter (/='\r')

-- | Convert UTF8-encoded ByteString to String, also
-- removing '\r' characters.
toString :: B.ByteString -> String
toString = T.unpack . toText

-- | Convert UTF8-encoded ByteString to Text, also
-- removing '\r' characters.
toTextLazy :: BL.ByteString -> TL.Text
toTextLazy = TL.decodeUtf8 . filterCRs . dropBOM
  where dropBOM bs =
         if "\xEF\xBB\xBF" `BL.isPrefixOf` bs
            then BL.drop 3 bs
            else bs
        filterCRs = BL.filter (/='\r')

-- | Convert UTF8-encoded ByteString to String, also
-- removing '\r' characters.
toStringLazy :: BL.ByteString -> String
toStringLazy = TL.unpack . toTextLazy

fromText :: T.Text -> B.ByteString
fromText = T.encodeUtf8

fromTextLazy :: TL.Text -> BL.ByteString
fromTextLazy = TL.encodeUtf8

fromString :: String -> B.ByteString
fromString = fromText . T.pack

fromStringLazy :: String -> BL.ByteString
fromStringLazy = fromTextLazy . TL.pack

encodePath :: FilePath -> FilePath
encodePath = id

decodeArg :: String -> String
decodeArg = id
