    {-# LANGUAGE MonoLocalBinds      #-}
    {-# LANGUAGE NoImplicitPrelude   #-}
    {-# LANGUAGE ScopedTypeVariables #-}

    {-
    Copyright (C) 2006-2018 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.Readers
       Copyright   : Copyright (C) 2006-2018 John MacFarlane
       License     : GNU GPL, version 2 or above

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

    This helper module exports the readers.

    Note:  all of the readers assume that the input text has @'\n'@
    line endings.  So if you get your input text from a web form,
    you should remove @'\r'@ characters using @filter (/='\r')@.

    -}

    module Text.Pandoc.Readers
      (
        -- * Readers: converting /to/ Pandoc format
        Reader (..)
      , readers
      , readDocx
      , readOdt
      , readMarkdown
      , readCommonMark
      , readCreole
      , readMediaWiki
      , readVimwiki
      , readRST
      , readOrg
      , readLaTeX
      , readHtml
      , readJATS
      , readTextile
      , readDocBook
      , readOPML
      , readHaddock
      , readNative
      , readJSON
      , readTWiki
      , readTikiWiki
      , readTxt2Tags
      , readEPUB
      , readMuse
      , readFB2
      -- * Miscellaneous
      , getReader
      , getDefaultExtensions
      ) where

    import Prelude
    import Control.Monad.Except (throwError)
    import Data.Aeson
    import qualified Data.ByteString.Lazy as BL
    import Data.List (intercalate)
    import Data.Text (Text)
    import Text.Pandoc.Class
    import Text.Pandoc.Definition
    import Text.Pandoc.Error
    import Text.Pandoc.Extensions
    import Text.Pandoc.Options
    import Text.Pandoc.Readers.CommonMark
    import Text.Pandoc.Readers.Creole
    import Text.Pandoc.Readers.DocBook
    import Text.Pandoc.Readers.Docx
    import Text.Pandoc.Readers.EPUB
    import Text.Pandoc.Readers.FB2
    import Text.Pandoc.Readers.Haddock
    import Text.Pandoc.Readers.HTML (readHtml)
    import Text.Pandoc.Readers.JATS (readJATS)
    import Text.Pandoc.Readers.LaTeX
    import Text.Pandoc.Readers.Markdown
    import Text.Pandoc.Readers.MediaWiki
    import Text.Pandoc.Readers.Muse
    import Text.Pandoc.Readers.Native
    import Text.Pandoc.Readers.Odt
    import Text.Pandoc.Readers.OPML
    import Text.Pandoc.Readers.Org
    import Text.Pandoc.Readers.RST
    import Text.Pandoc.Readers.Textile
    import Text.Pandoc.Readers.TikiWiki
    import Text.Pandoc.Readers.TWiki
    import Text.Pandoc.Readers.Txt2Tags
    import Text.Pandoc.Readers.Vimwiki
    import Text.Pandoc.Readers.Man
    import Text.Pandoc.Shared (mapLeft)
    import qualified Text.Pandoc.UTF8 as UTF8
    import Text.Parsec.Error

    data Reader m = TextReader (ReaderOptions -> Text -> m Pandoc)
                  | ByteStringReader (ReaderOptions -> BL.ByteString -> m Pandoc)

    -- | Association list of formats and readers.
    readers :: PandocMonad m => [(String, Reader m)]
    readers = [ ("native"       , TextReader readNative)
               ,("json"         , TextReader $ \o s ->
                                                   case readJSON o s of
                                                     Right doc -> return doc
                                                     Left _ -> throwError $ PandocParseError "JSON parse error")
               ,("markdown"     , TextReader readMarkdown)
               ,("markdown_strict" , TextReader readMarkdown)
               ,("markdown_phpextra" , TextReader readMarkdown)
               ,("markdown_github" , TextReader readMarkdown)
               ,("markdown_mmd",  TextReader readMarkdown)
               ,("commonmark"   , TextReader readCommonMark)
               ,("creole"       , TextReader readCreole)
               ,("gfm"          , TextReader readCommonMark)
               ,("rst"          , TextReader readRST)
               ,("mediawiki"    , TextReader readMediaWiki)
               ,("vimwiki"      , TextReader readVimwiki)
               ,("docbook"      , TextReader readDocBook)
               ,("opml"         , TextReader readOPML)
               ,("org"          , TextReader readOrg)
               ,("textile"      , TextReader readTextile) -- TODO : textile+lhs
               ,("html"         , TextReader readHtml)
               ,("jats"         , TextReader readJATS)
               ,("latex"        , TextReader readLaTeX)
               ,("haddock"      , TextReader readHaddock)
               ,("twiki"        , TextReader readTWiki)
               ,("tikiwiki"     , TextReader readTikiWiki)
               ,("docx"         , ByteStringReader readDocx)
               ,("odt"          , ByteStringReader readOdt)
               ,("t2t"          , TextReader readTxt2Tags)
               ,("epub"         , ByteStringReader readEPUB)
               ,("muse"         , TextReader readMuse)
               ,("man"          , TextReader readMan)
               ,("fb2"          , TextReader readFB2)
               ]

    -- | Retrieve reader, extensions based on formatSpec (format+extensions).
    getReader :: PandocMonad m => String -> Either String (Reader m, Extensions)
    getReader s =
      case parseFormatSpec s of
           Left e  -> Left $ intercalate "\n" [m | Message m <- errorMessages e]
           Right (readerName, setExts) ->
               case lookup readerName readers of
                       Nothing  -> Left $ "Unknown reader: " ++ readerName
                       Just  r  -> Right (r, setExts $
                                            getDefaultExtensions readerName)

    -- | Read pandoc document from JSON format.
    readJSON :: ReaderOptions -> Text -> Either PandocError Pandoc
    readJSON _ =
      mapLeft PandocParseError . eitherDecode' . BL.fromStrict . UTF8.fromText