    {-# LANGUAGE ScopedTypeVariables, FlexibleInstances #-}
    {-
    Copyright (C) 2006-2015 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
       Copyright   : Copyright (C) 2006-2015 John MacFarlane
       License     : GNU GPL, version 2 or above

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

    This helper module exports the main writers, readers, and data
    structure definitions from the Pandoc libraries.

    A typical application will chain together a reader and a writer
    to convert strings from one format to another.  For example, the
    following simple program will act as a filter converting markdown
    fragments to reStructuredText, using reference-style links instead of
    inline links:

    > module Main where
    > import Text.Pandoc
    > import Text.Pandoc.Error (handleError)
    >
    > markdownToRST :: String -> String
    > markdownToRST = handleError .
    >   writeRST def {writerReferenceLinks = True} .
    >   readMarkdown def
    >
    > main = getContents >>= putStrLn . markdownToRST

    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
                   (
                   -- * Definitions
                   module Text.Pandoc.Definition
                   -- * Generics
                   , module Text.Pandoc.Generic
                   -- * Options
                   , module Text.Pandoc.Options
                   -- * Lists of readers and writers
                   , readers
                   , writers
                   -- * Readers: converting /to/ Pandoc format
                   , Reader (..)
                   , mkStringReader
                   , readDocx
                   , readOdt
                   , readMarkdown
                   , readCommonMark
                   , readMediaWiki
                   , readRST
                   , readOrg
                   , readLaTeX
                   , readHtml
                   , readTextile
                   , readDocBook
                   , readOPML
                   , readHaddock
                   , readNative
                   , readJSON
                   , readTWiki
                   , readTxt2Tags
                   , readTxt2TagsNoMacros
                   , readEPUB
                   -- * Writers: converting /from/ Pandoc format
                  , Writer (..)
                   , writeNative
                   , writeJSON
                   , writeMarkdown
                   , writePlain
                   , writeRST
                   , writeLaTeX
                   , writeConTeXt
                   , writeTexinfo
                   , writeHtml
                   , writeHtmlString
                   , writeICML
                   , writeDocbook
                   , writeOPML
                   , writeOpenDocument
                   , writeMan
                   , writeMediaWiki
                   , writeDokuWiki
                   , writeTextile
                   , writeRTF
                   , writeODT
                   , writeDocx
                   , writeEPUB
                   , writeFB2
                   , writeOrg
                   , writeAsciiDoc
                   , writeHaddock
                   , writeCommonMark
                   , writeCustom
                   -- * Rendering templates and default templates
                   , module Text.Pandoc.Templates
                   -- * Miscellaneous
                   , getReader
                   , getWriter
                   , ToJsonFilter(..)
                   , pandocVersion
                 ) where

    import Text.Pandoc.Definition
    import Text.Pandoc.Generic
    import Text.Pandoc.JSON
    import Text.Pandoc.Readers.Markdown
    import Text.Pandoc.Readers.CommonMark
    import Text.Pandoc.Readers.MediaWiki
    import Text.Pandoc.Readers.RST
    import Text.Pandoc.Readers.Org
    import Text.Pandoc.Readers.DocBook
    import Text.Pandoc.Readers.OPML
    import Text.Pandoc.Readers.LaTeX
    import Text.Pandoc.Readers.HTML
    import Text.Pandoc.Readers.Textile
    import Text.Pandoc.Readers.Native
    import Text.Pandoc.Readers.Haddock
    import Text.Pandoc.Readers.TWiki
    import Text.Pandoc.Readers.Docx
    import Text.Pandoc.Readers.Odt
    import Text.Pandoc.Readers.Txt2Tags
    import Text.Pandoc.Readers.EPUB
    import Text.Pandoc.Writers.Native
    import Text.Pandoc.Writers.Markdown
    import Text.Pandoc.Writers.RST
    import Text.Pandoc.Writers.LaTeX
    import Text.Pandoc.Writers.ConTeXt
    import Text.Pandoc.Writers.Texinfo
    import Text.Pandoc.Writers.HTML
    import Text.Pandoc.Writers.ODT
    import Text.Pandoc.Writers.Docx
    import Text.Pandoc.Writers.EPUB
    import Text.Pandoc.Writers.FB2
    import Text.Pandoc.Writers.ICML
    import Text.Pandoc.Writers.Docbook
    import Text.Pandoc.Writers.OPML
    import Text.Pandoc.Writers.OpenDocument
    import Text.Pandoc.Writers.Man
    import Text.Pandoc.Writers.RTF
    import Text.Pandoc.Writers.MediaWiki
    import Text.Pandoc.Writers.DokuWiki
    import Text.Pandoc.Writers.Textile
    import Text.Pandoc.Writers.Org
    import Text.Pandoc.Writers.AsciiDoc
    import Text.Pandoc.Writers.Haddock
    import Text.Pandoc.Writers.CommonMark
    import Text.Pandoc.Writers.Custom
    import Text.Pandoc.Templates
    import Text.Pandoc.Options
    import Text.Pandoc.Shared (safeRead, warn, mapLeft, pandocVersion)
    import Text.Pandoc.MediaBag (MediaBag)
    import Text.Pandoc.Error
    import Data.Aeson
    import qualified Data.ByteString.Lazy as BL
    import Data.List (intercalate)
    import Data.Set (Set)
    import qualified Data.Set as Set
    import Text.Parsec
    import Text.Parsec.Error
    import qualified Text.Pandoc.UTF8 as UTF8

    parseFormatSpec :: String
                    -> Either ParseError (String, Set Extension -> Set Extension)
    parseFormatSpec = parse formatSpec ""
      where formatSpec = do
              name <- formatName
              extMods <- many extMod
              return (name, foldl (.) id extMods)
            formatName = many1 $ noneOf "-+"
            extMod = do
              polarity <- oneOf "-+"
              name <- many $ noneOf "-+"
              ext <- case safeRead ("Ext_" ++ name) of
                           Just n  -> return n
                           Nothing
                             | name == "lhs" -> return Ext_literate_haskell
                             | otherwise -> fail $ "Unknown extension: " ++ name
              return $ case polarity of
                            '-'  -> Set.delete ext
                            _    -> Set.insert ext

    data Reader = StringReader (ReaderOptions -> String -> IO (Either PandocError Pandoc))
                  | ByteStringReader (ReaderOptions -> BL.ByteString -> IO (Either PandocError (Pandoc,MediaBag)))

    mkStringReader :: (ReaderOptions -> String -> Either PandocError Pandoc) -> Reader
    mkStringReader r = StringReader (\o s -> return $ r o s)

    mkStringReaderWithWarnings :: (ReaderOptions -> String -> Either PandocError (Pandoc, [String])) -> Reader
    mkStringReaderWithWarnings r  = StringReader $ \o s ->
      case r o s of
        Left err -> return $ Left err
        Right (doc, warnings) -> do
          mapM_ warn warnings
          return (Right doc)

    mkBSReader :: (ReaderOptions -> BL.ByteString -> Either PandocError (Pandoc, MediaBag)) -> Reader
    mkBSReader r = ByteStringReader (\o s -> return $ r o s)

    -- | Association list of formats and readers.
    readers :: [(String, Reader)]
    readers = [ ("native"       , StringReader $ \_ s -> return $ readNative s)
               ,("json"         , mkStringReader readJSON )
               ,("markdown"     , mkStringReaderWithWarnings readMarkdownWithWarnings)
               ,("markdown_strict" , mkStringReaderWithWarnings readMarkdownWithWarnings)
               ,("markdown_phpextra" , mkStringReaderWithWarnings readMarkdownWithWarnings)
               ,("markdown_github" , mkStringReaderWithWarnings readMarkdownWithWarnings)
               ,("markdown_mmd",  mkStringReaderWithWarnings readMarkdownWithWarnings)
               ,("commonmark"   , mkStringReader readCommonMark)
               ,("rst"          , mkStringReaderWithWarnings readRSTWithWarnings )
               ,("mediawiki"    , mkStringReader readMediaWiki)
               ,("docbook"      , mkStringReader readDocBook)
               ,("opml"         , mkStringReader readOPML)
               ,("org"          , mkStringReader readOrg)
               ,("textile"      , mkStringReader readTextile) -- TODO : textile+lhs
               ,("html"         , mkStringReader readHtml)
               ,("latex"        , mkStringReader readLaTeX)
               ,("haddock"      , mkStringReader readHaddock)
               ,("twiki"        , mkStringReader readTWiki)
               ,("docx"         , mkBSReader readDocx)
               ,("odt"          , mkBSReader readOdt)
               ,("t2t"          , mkStringReader readTxt2TagsNoMacros)
               ,("epub"         , mkBSReader readEPUB)
               ]

    data Writer = PureStringWriter   (WriterOptions -> Pandoc -> String)
                | IOStringWriter     (WriterOptions -> Pandoc -> IO String)
                | IOByteStringWriter (WriterOptions -> Pandoc -> IO BL.ByteString)

    -- | Association list of formats and writers.
    writers :: [ ( String, Writer ) ]
    writers = [
       ("native"       , PureStringWriter writeNative)
      ,("json"         , PureStringWriter writeJSON)
      ,("docx"         , IOByteStringWriter writeDocx)
      ,("odt"          , IOByteStringWriter writeODT)
      ,("epub"         , IOByteStringWriter $ \o ->
                          writeEPUB o{ writerEpubVersion = Just EPUB2 })
      ,("epub3"        , IOByteStringWriter $ \o ->
                           writeEPUB o{ writerEpubVersion = Just EPUB3 })
      ,("fb2"          , IOStringWriter writeFB2)
      ,("html"         , PureStringWriter writeHtmlString)
      ,("html5"        , PureStringWriter $ \o ->
         writeHtmlString o{ writerHtml5 = True })
      ,("icml"         , IOStringWriter writeICML)
      ,("s5"           , PureStringWriter $ \o ->
         writeHtmlString o{ writerSlideVariant = S5Slides
                          , writerTableOfContents = False })
      ,("slidy"        , PureStringWriter $ \o ->
         writeHtmlString o{ writerSlideVariant = SlidySlides })
      ,("slideous"     , PureStringWriter $ \o ->
         writeHtmlString o{ writerSlideVariant = SlideousSlides })
      ,("dzslides"     , PureStringWriter $ \o ->
         writeHtmlString o{ writerSlideVariant = DZSlides
                          , writerHtml5 = True })
      ,("revealjs"      , PureStringWriter $ \o ->
         writeHtmlString o{ writerSlideVariant = RevealJsSlides
                          , writerHtml5 = True })
      ,("docbook"      , PureStringWriter writeDocbook)
      ,("opml"         , PureStringWriter writeOPML)
      ,("opendocument" , PureStringWriter writeOpenDocument)
      ,("latex"        , PureStringWriter writeLaTeX)
      ,("beamer"       , PureStringWriter $ \o ->
         writeLaTeX o{ writerBeamer = True })
      ,("context"      , PureStringWriter writeConTeXt)
      ,("texinfo"      , PureStringWriter writeTexinfo)
      ,("man"          , PureStringWriter writeMan)
      ,("markdown"     , PureStringWriter writeMarkdown)
      ,("markdown_strict" , PureStringWriter writeMarkdown)
      ,("markdown_phpextra" , PureStringWriter writeMarkdown)
      ,("markdown_github" , PureStringWriter writeMarkdown)
      ,("markdown_mmd" , PureStringWriter writeMarkdown)
      ,("plain"        , PureStringWriter writePlain)
      ,("rst"          , PureStringWriter writeRST)
      ,("mediawiki"    , PureStringWriter writeMediaWiki)
      ,("dokuwiki"     , PureStringWriter writeDokuWiki)
      ,("textile"      , PureStringWriter writeTextile)
      ,("rtf"          , IOStringWriter writeRTFWithEmbeddedImages)
      ,("org"          , PureStringWriter writeOrg)
      ,("asciidoc"     , PureStringWriter writeAsciiDoc)
      ,("haddock"      , PureStringWriter writeHaddock)
      ,("commonmark"   , PureStringWriter writeCommonMark)
      ]

    getDefaultExtensions :: String -> Set Extension
    getDefaultExtensions "markdown_strict" = strictExtensions
    getDefaultExtensions "markdown_phpextra" = phpMarkdownExtraExtensions
    getDefaultExtensions "markdown_mmd" = multimarkdownExtensions
    getDefaultExtensions "markdown_github" = githubMarkdownExtensions
    getDefaultExtensions "markdown"        = pandocExtensions
    getDefaultExtensions "plain"           = plainExtensions
    getDefaultExtensions "org"             = Set.fromList [Ext_citations,
                                                           Ext_auto_identifiers]
    getDefaultExtensions "textile"         = Set.fromList [Ext_auto_identifiers]
    getDefaultExtensions "html"            = Set.fromList [Ext_auto_identifiers,
                                                           Ext_native_divs,
                                                           Ext_native_spans]
    getDefaultExtensions "html5"           = getDefaultExtensions "html"
    getDefaultExtensions "epub"            = Set.fromList [Ext_raw_html,
                                                           Ext_native_divs,
                                                           Ext_native_spans,
                                                           Ext_epub_html_exts]
    getDefaultExtensions _                 = Set.fromList [Ext_auto_identifiers]

    -- | Retrieve reader based on formatSpec (format+extensions).
    getReader :: String -> Either String Reader
    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  (StringReader r)  -> Right $ StringReader $ \o ->
                                      r o{ readerExtensions = setExts $
                                                getDefaultExtensions readerName }
                       Just (ByteStringReader r) -> Right $ ByteStringReader $ \o ->
                                      r o{ readerExtensions = setExts $
                                                getDefaultExtensions readerName }

    -- | Retrieve writer based on formatSpec (format+extensions).
    getWriter :: String -> Either String Writer
    getWriter s
      = case parseFormatSpec s of
             Left e  -> Left $ intercalate "\n" [m | Message m <- errorMessages e]
             Right (writerName, setExts) ->
                 case lookup writerName writers of
                         Nothing -> Left $ "Unknown writer: " ++ writerName
                         Just (PureStringWriter r) -> Right $ PureStringWriter $
                                 \o -> r o{ writerExtensions = setExts $
                                                  getDefaultExtensions writerName }
                         Just (IOStringWriter r) -> Right $ IOStringWriter $
                                 \o -> r o{ writerExtensions = setExts $
                                                  getDefaultExtensions writerName }
                         Just (IOByteStringWriter r) -> Right $ IOByteStringWriter $
                                 \o -> r o{ writerExtensions = setExts $
                                                  getDefaultExtensions writerName }

    {-# DEPRECATED toJsonFilter "Use 'toJSONFilter' from 'Text.Pandoc.JSON' instead" #-}
    -- | Deprecated.  Use @toJSONFilter@ from @Text.Pandoc.JSON@ instead.
    class ToJSONFilter a => ToJsonFilter a
      where toJsonFilter :: a -> IO ()
            toJsonFilter = toJSONFilter

    readJSON :: ReaderOptions -> String -> Either PandocError Pandoc
    readJSON _ = mapLeft ParseFailure . eitherDecode' . UTF8.fromStringLazy

    writeJSON :: WriterOptions -> Pandoc -> String
    writeJSON _ = UTF8.toStringLazy . encode