{-# LANGUAGE PatternGuards #-}

{-
Copyright (C) 2015 Martin Linnemann <theCodingMarlin@googlemail.com>

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.Reader.Odt
   Copyright   : Copyright (C) 2015 Martin Linnemann
   License     : GNU GPL, version 2 or above

   Maintainer  : Martin Linnemann <theCodingMarlin@googlemail.com>
   Stability   : alpha
   Portability : portable

Entry point to the odt reader.
-}

module Text.Pandoc.Readers.Odt ( readOdt ) where

import           Codec.Archive.Zip
import qualified Text.XML.Light                        as XML

import qualified Data.ByteString.Lazy                  as B
import           Data.Monoid                                   ( mempty )

import           Text.Pandoc.Definition
import           Text.Pandoc.Error
import           Text.Pandoc.Options
import           Text.Pandoc.MediaBag
import qualified Text.Pandoc.UTF8                      as UTF8

import           Text.Pandoc.Readers.Odt.ContentReader
import           Text.Pandoc.Readers.Odt.StyleReader

import           Text.Pandoc.Readers.Odt.Generic.XMLConverter
import           Text.Pandoc.Readers.Odt.Generic.Fallible

--
readOdt :: ReaderOptions
        -> B.ByteString
        -> Either PandocError (Pandoc, MediaBag)
readOdt _ bytes = case bytesToOdt bytes of
                    Right pandoc -> Right (pandoc , mempty)
                    Left  err    -> Left err

--
bytesToOdt :: B.ByteString -> Either PandocError Pandoc
bytesToOdt bytes = archiveToOdt $ toArchive bytes

--
archiveToOdt :: Archive -> Either PandocError Pandoc
archiveToOdt archive
  | Just contentEntry <- findEntryByPath "content.xml" archive
  , Just stylesEntry  <- findEntryByPath "styles.xml"  archive
  , Just contentElem  <- entryToXmlElem contentEntry
  , Just stylesElem   <- entryToXmlElem stylesEntry
  , Right styles      <- chooseMax (readStylesAt stylesElem )
                                   (readStylesAt contentElem)
  , startState        <- readerState styles
  , Right pandoc      <- runConverter' read_body
                                       startState
                                       contentElem
  = Right pandoc

  | otherwise
    -- Not very detailed, but I don't think more information would be helpful
  = Left $ ParseFailure "Couldn't parse odt file."

--
entryToXmlElem :: Entry -> Maybe XML.Element
entryToXmlElem = XML.parseXMLDoc . UTF8.toStringLazy . fromEntry
