    {-# LANGUAGE NoImplicitPrelude #-}
    {-
    Copyright (C) 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.LaTeX.Lang
       Copyright   : Copyright (C) 2018 John MacFarlane
       License     : GNU GPL, version 2 or above

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

    Functions for parsing polyglossia and babel language specifiers to
    BCP47 'Lang'.
    -}
    module Text.Pandoc.Readers.LaTeX.Lang
      ( polyglossiaLangToBCP47
      , babelLangToBCP47
      )
    where
    import Prelude
    import qualified Data.Map as M
    import Text.Pandoc.BCP47 (Lang(..))

    polyglossiaLangToBCP47 :: M.Map String (String -> Lang)
    polyglossiaLangToBCP47 = M.fromList
      [ ("arabic", \o -> case filter (/=' ') o of
           "locale=algeria"    -> Lang "ar" "" "DZ" []
           "locale=mashriq"    -> Lang "ar" "" "SY" []
           "locale=libya"      -> Lang "ar" "" "LY" []
           "locale=morocco"    -> Lang "ar" "" "MA" []
           "locale=mauritania" -> Lang "ar" "" "MR" []
           "locale=tunisia"    -> Lang "ar" "" "TN" []
           _                   -> Lang "ar" "" "" [])
      , ("german", \o -> case filter (/=' ') o of
           "spelling=old" -> Lang "de" "" "DE" ["1901"]
           "variant=austrian,spelling=old"
                           -> Lang "de" "" "AT" ["1901"]
           "variant=austrian" -> Lang "de" "" "AT" []
           "variant=swiss,spelling=old"
                           -> Lang "de" "" "CH" ["1901"]
           "variant=swiss" -> Lang "de" "" "CH" []
           _ -> Lang "de" "" "" [])
      , ("lsorbian", \_ -> Lang "dsb" "" "" [])
      , ("greek", \o -> case filter (/=' ') o of
           "variant=poly"    -> Lang "el" "" "polyton" []
           "variant=ancient" -> Lang "grc" "" "" []
           _                 -> Lang "el" "" "" [])
      , ("english", \o -> case filter (/=' ') o of
           "variant=australian" -> Lang "en" "" "AU" []
           "variant=canadian"   -> Lang "en" "" "CA" []
           "variant=british"    -> Lang "en" "" "GB" []
           "variant=newzealand" -> Lang "en" "" "NZ" []
           "variant=american"   -> Lang "en" "" "US" []
           _                    -> Lang "en" "" "" [])
      , ("usorbian", \_ -> Lang "hsb" "" "" [])
      , ("latin", \o -> case filter (/=' ') o of
           "variant=classic" -> Lang "la" "" "" ["x-classic"]
           _                 -> Lang "la" "" "" [])
      , ("slovenian", \_ -> Lang "sl" "" "" [])
      , ("serbianc", \_ -> Lang "sr" "cyrl" "" [])
      , ("pinyin", \_ -> Lang "zh" "Latn" "" ["pinyin"])
      , ("afrikaans", \_ -> Lang "af" "" "" [])
      , ("amharic", \_ -> Lang "am" "" "" [])
      , ("assamese", \_ -> Lang "as" "" "" [])
      , ("asturian", \_ -> Lang "ast" "" "" [])
      , ("bulgarian", \_ -> Lang "bg" "" "" [])
      , ("bengali", \_ -> Lang "bn" "" "" [])
      , ("tibetan", \_ -> Lang "bo" "" "" [])
      , ("breton", \_ -> Lang "br" "" "" [])
      , ("catalan", \_ -> Lang "ca" "" "" [])
      , ("welsh", \_ -> Lang "cy" "" "" [])
      , ("czech", \_ -> Lang "cs" "" "" [])
      , ("coptic", \_ -> Lang "cop" "" "" [])
      , ("danish", \_ -> Lang "da" "" "" [])
      , ("divehi", \_ -> Lang "dv" "" "" [])
      , ("esperanto", \_ -> Lang "eo" "" "" [])
      , ("spanish", \_ -> Lang "es" "" "" [])
      , ("estonian", \_ -> Lang "et" "" "" [])
      , ("basque", \_ -> Lang "eu" "" "" [])
      , ("farsi", \_ -> Lang "fa" "" "" [])
      , ("finnish", \_ -> Lang "fi" "" "" [])
      , ("french", \_ -> Lang "fr" "" "" [])
      , ("friulan", \_ -> Lang "fur" "" "" [])
      , ("irish", \_ -> Lang "ga" "" "" [])
      , ("scottish", \_ -> Lang "gd" "" "" [])
      , ("ethiopic", \_ -> Lang "gez" "" "" [])
      , ("galician", \_ -> Lang "gl" "" "" [])
      , ("hebrew", \_ -> Lang "he" "" "" [])
      , ("hindi", \_ -> Lang "hi" "" "" [])
      , ("croatian", \_ -> Lang "hr" "" "" [])
      , ("magyar", \_ -> Lang "hu" "" "" [])
      , ("armenian", \_ -> Lang "hy" "" "" [])
      , ("interlingua", \_ -> Lang "ia" "" "" [])
      , ("indonesian", \_ -> Lang "id" "" "" [])
      , ("icelandic", \_ -> Lang "is" "" "" [])
      , ("italian", \_ -> Lang "it" "" "" [])
      , ("japanese", \_ -> Lang "jp" "" "" [])
      , ("khmer", \_ -> Lang "km" "" "" [])
      , ("kurmanji", \_ -> Lang "kmr" "" "" [])
      , ("kannada", \_ -> Lang "kn" "" "" [])
      , ("korean", \_ -> Lang "ko" "" "" [])
      , ("lao", \_ -> Lang "lo" "" "" [])
      , ("lithuanian", \_ -> Lang "lt" "" "" [])
      , ("latvian", \_ -> Lang "lv" "" "" [])
      , ("malayalam", \_ -> Lang "ml" "" "" [])
      , ("mongolian", \_ -> Lang "mn" "" "" [])
      , ("marathi", \_ -> Lang "mr" "" "" [])
      , ("dutch", \_ -> Lang "nl" "" "" [])
      , ("nynorsk", \_ -> Lang "nn" "" "" [])
      , ("norsk", \_ -> Lang "no" "" "" [])
      , ("nko", \_ -> Lang "nqo" "" "" [])
      , ("occitan", \_ -> Lang "oc" "" "" [])
      , ("panjabi", \_ -> Lang "pa" "" "" [])
      , ("polish", \_ -> Lang "pl" "" "" [])
      , ("piedmontese", \_ -> Lang "pms" "" "" [])
      , ("portuguese", \_ -> Lang "pt" "" "" [])
      , ("romansh", \_ -> Lang "rm" "" "" [])
      , ("romanian", \_ -> Lang "ro" "" "" [])
      , ("russian", \_ -> Lang "ru" "" "" [])
      , ("sanskrit", \_ -> Lang "sa" "" "" [])
      , ("samin", \_ -> Lang "se" "" "" [])
      , ("slovak", \_ -> Lang "sk" "" "" [])
      , ("albanian", \_ -> Lang "sq" "" "" [])
      , ("serbian", \_ -> Lang "sr" "" "" [])
      , ("swedish", \_ -> Lang "sv" "" "" [])
      , ("syriac", \_ -> Lang "syr" "" "" [])
      , ("tamil", \_ -> Lang "ta" "" "" [])
      , ("telugu", \_ -> Lang "te" "" "" [])
      , ("thai", \_ -> Lang "th" "" "" [])
      , ("turkmen", \_ -> Lang "tk" "" "" [])
      , ("turkish", \_ -> Lang "tr" "" "" [])
      , ("ukrainian", \_ -> Lang "uk" "" "" [])
      , ("urdu", \_ -> Lang "ur" "" "" [])
      , ("vietnamese", \_ -> Lang "vi" "" "" [])
      ]

    babelLangToBCP47 :: String -> Maybe Lang
    babelLangToBCP47 s =
      case s of
           "austrian" -> Just $ Lang "de" "" "AT" ["1901"]
           "naustrian" -> Just $ Lang "de" "" "AT" []
           "swissgerman" -> Just $ Lang "de" "" "CH" ["1901"]
           "nswissgerman" -> Just $ Lang "de" "" "CH" []
           "german" -> Just $ Lang "de" "" "DE" ["1901"]
           "ngerman" -> Just $ Lang "de" "" "DE" []
           "lowersorbian" -> Just $ Lang "dsb" "" "" []
           "uppersorbian" -> Just $ Lang "hsb" "" "" []
           "polutonikogreek" -> Just $ Lang "el" "" "" ["polyton"]
           "slovene" -> Just $ Lang "sl" "" "" []
           "australian" -> Just $ Lang "en" "" "AU" []
           "canadian" -> Just $ Lang "en" "" "CA" []
           "british" -> Just $ Lang "en" "" "GB" []
           "newzealand" -> Just $ Lang "en" "" "NZ" []
           "american" -> Just $ Lang "en" "" "US" []
           "classiclatin" -> Just $ Lang "la" "" "" ["x-classic"]
           _ -> fmap ($ "") $ M.lookup s polyglossiaLangToBCP47