{-# LANGUAGE ViewPatterns      #-}
{-# LANGUAGE LambdaCase #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE FlexibleContexts #-}
{-# OPTIONS_GHC -fno-warn-unused-do-bind #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Text.CSL.Input.Bibtex
-- Copyright   :  (c) John MacFarlane
-- License     :  BSD-style (see LICENSE)
--
-- Maintainer  :  John MacFarlane <fiddlosopher@gmail.com>
-- Stability   :  unstable
-- Portability :  portable
--
-----------------------------------------------------------------------------

module Text.Pandoc.Citeproc.BibTeX
    ( Variant(..)
    , readBibtexString
    , writeBibtexString
    )
    where

import Text.Pandoc.Definition
import Text.Pandoc.Builder as B
import Text.Pandoc.Readers.LaTeX (readLaTeX)
import Text.Pandoc.Extensions (Extension(..), extensionsFromList)
import Text.Pandoc.Options (ReaderOptions(..), WriterOptions)
import Text.Pandoc.Error (PandocError)
import Text.Pandoc.Shared (stringify)
import Text.Pandoc.Writers.LaTeX (writeLaTeX)
import Text.Pandoc.Class (runPure)
import qualified Text.Pandoc.Walk       as Walk
import Citeproc.Types
import Citeproc.Pandoc ()
import Data.List.Split (splitOn)
import Text.Pandoc.Citeproc.Util (toIETF, splitStrWhen)
import Text.Pandoc.Citeproc.Data (biblatexStringMap)
import Text.Pandoc.Citeproc.Name (toName, NameOpts(..), emptyName)
import Data.Default
import           Data.Text              (Text)
import qualified Data.Text              as T
import qualified Data.Map               as Map
import           Data.Maybe
import           Text.Pandoc.Parsing hiding ((<|>), many)
import           Control.Applicative
import           Control.Monad ( guard, MonadPlus(..), void )
import Control.Monad.RWS ( asks, RWST, gets, modify, evalRWST )
import qualified Data.Sequence          as Seq
import           Data.Char              (isAlphaNum, isDigit, isLetter,
                                         isUpper, toLower, toUpper,
                                         isLower, isPunctuation, isSpace)
import           Data.List              (foldl', intercalate, intersperse)
import           Safe                   (readMay)
import           Text.Printf            (printf)
import           Text.DocLayout         (literal, hsep, nest, hang, Doc(..),
                                         braces, ($$), cr)
data Variant = Bibtex | Biblatex
  deriving (Show, Eq, Ord)

-- | Parse BibTeX or BibLaTeX into a list of 'Reference's.
readBibtexString :: ToSources a
                 => Variant           -- ^ bibtex or biblatex
                 -> Locale            -- ^ Locale
                 -> (Text -> Bool)    -- ^ Filter on citation ids
                 -> a                 -- ^ bibtex/biblatex text
                 -> Either ParseError [Reference Inlines]
readBibtexString variant locale idpred contents = do
  case runParser (((resolveCrossRefs variant <$> bibEntries) <* eof) >>=
                   mapM (itemToReference locale variant) .
                      filter (\item -> idpred (identifier item) &&
                                        entryType item /= "xdata"))
           (fromMaybe defaultLang $ localeLanguage locale, Map.empty)
           (initialSourceName sources) sources of
          Left err -> Left err
          Right xs -> return xs
 where
  sources = toSources contents

-- | Write BibTeX or BibLaTeX given given a 'Reference'.
writeBibtexString :: WriterOptions       -- ^ options (for writing LaTex)
                  -> Variant             -- ^ bibtex or biblatex
                  -> Maybe Lang          -- ^ Language
                  -> Reference Inlines   -- ^ Reference to write
                  -> Doc Text
writeBibtexString opts variant mblang ref =
  "@" <> bibtexType <> "{" <> literal (unItemId (referenceId ref)) <> ","
  $$ nest 2 (renderFields fs)
  $$ "}" <> cr

 where
  bibtexType =
    case referenceType ref of
      "article-magazine"  -> "article"
      "article-newspaper" -> "article"
      "article-journal"   -> "article"
      "book"              -> "book"
      "pamphlet"          -> "booklet"
      "dataset" | variant == Biblatex -> "dataset"
      "webpage" | variant == Biblatex -> "online"
      "chapter"           -> case getVariable "editor" of
                                Just _  -> "incollection"
                                Nothing -> "inbook"
      "entry-encyclopedia" | variant == Biblatex -> "inreference"
                           | otherwise -> "inbook"
      "paper-conference"  -> "inproceedings"
      "thesis" -> case getVariableAsText "genre" of
                    Just "mathesis" -> "mastersthesis"
                    _               -> "phdthesis"
      "patent"            | variant == Biblatex -> "patent"
      "report"            | variant == Biblatex -> "report"
                          | otherwise -> "techreport"
      "speech"            -> "unpublished"
      "manuscript"        -> "unpublished"
      "graphic"           | variant == Biblatex -> "artwork"
      "song"              | variant == Biblatex -> "music"
      "legal_case"        | variant == Biblatex -> "jurisdictionN"
      "legislation"       | variant == Biblatex -> "legislation"
      "treaty"            | variant == Biblatex -> "legal"
      "personal_communication" | variant == Biblatex -> "letter"
      "motion_picture"    | variant == Biblatex -> "movie"
      "review"            | variant == Biblatex -> "review"
      "software"          | variant == Biblatex -> "software"
      _                   -> "misc"

  mbSubtype =
    case referenceType ref of
      "article-magazine"  -> Just "magazine"
      "article-newspaper" -> Just "newspaper"
      _ -> Nothing

  fs =
    case variant of
      Biblatex ->
           [ "author"
           , "editor"
           , "translator"
           , "publisher"
           , "title"
           , "booktitle"
           , "journal"
           , "series"
           , "edition"
           , "volume"
           , "volumes"
           , "number"
           , "pages"
           , "pagetotal"
           , "version"
           , "date"
           , "eventdate"
           , "urldate"
           , "address"
           , "url"
           , "doi"
           , "isbn"
           , "issn"
           , "type"
           , "entrysubtype"
           , "note"
           , "langid"
           , "abstract"
           , "keywords"
           , "annote"
           ]
      Bibtex ->
           [ "author"
           , "editor"
           , "translator"
           , "publisher"
           , "title"
           , "booktitle"
           , "journal"
           , "series"
           , "edition"
           , "volume"
           , "number"
           , "pages"
           , "year"
           , "month"
           , "address"
           , "type"
           , "note"
           , "annote"
           , "url" -- not officially supported, but supported by
                   -- some styles (#8287)
           ]

  valToInlines (TextVal t) = B.text t
  valToInlines (FancyVal ils) = ils
  valToInlines (NumVal n) = B.text (T.pack $ show n)
  valToInlines (NamesVal names) =
    mconcat $ intersperse (B.space <> B.text "and" <> B.space)
            $ map renderName names
  valToInlines (DateVal date) = B.text $
    case dateLiteral date of
      Just t  -> t
      Nothing -> T.intercalate "/" (map renderDatePart (dateParts date)) <>
                    (if dateCirca date then "~" else mempty)
  valToInlines SubstitutedVal = mempty

  renderDatePart (DateParts xs) = T.intercalate "-" $
                                    map (T.pack . printf "%02d") xs

  renderName name =
    case nameLiteral name of
      Just t  -> B.spanWith ("",[],[]) $ B.text t
      Nothing -> spacedMaybes
                  [ nameNonDroppingParticle name
                  , nameFamily name
                  , if nameCommaSuffix name
                        then (", " <>) <$> nameSuffix name
                        else nameSuffix name ]
                  <>
                  spacedMaybes
                   [ (", " <>) <$> nameGiven name,
                     nameDroppingParticle name ]

  mblang' = case getVariableAsText "language" of
              Just l  -> either (const Nothing) Just $ parseLang l
              Nothing -> mblang

  titlecase = case mblang' of
                Just lang | langLanguage lang == "en"
                                   -> titlecase'
                Nothing            -> titlecase'
                _                  ->
                  case variant of
                    Bibtex         -> B.spanWith nullAttr
                     -- BibTex lacks a language field, so we wrap non-English
                     -- titles in {} to protect case.
                    Biblatex       -> id

  titlecase' = addTextCase mblang' TitleCase .
    (\ils -> B.fromList
               (case B.toList ils of
                  Str t : xs -> Str t : Walk.walk spanAroundCapitalizedWords xs
                  xs         -> Walk.walk spanAroundCapitalizedWords xs))

  -- protect capitalized words when we titlecase
  spanAroundCapitalizedWords (Str t)
    | not (T.all (\c -> isLower c || not (isLetter c)) t) =
       Span ("",["nocase"],[]) [Str t]
  spanAroundCapitalizedWords x = x

  spacedMaybes = mconcat . intersperse B.space . mapMaybe (fmap B.text)

  toLaTeX x =
    case runPure (writeLaTeX opts $ doc (B.plain x)) of
           Left _  -> Nothing
           Right t -> Just $ hsep . map literal $ T.words t

  renderField :: Text -> Maybe (Doc Text)
  renderField name =
    (((literal name) <>) . hang 2 " = " . braces)
      <$> getContentsFor name

  getVariable v = lookupVariable (toVariable v) ref

  getVariableAsText v = (stringify . valToInlines) <$> getVariable v

  getYear val =
    case val of
       DateVal date ->
         case dateLiteral date of
           Just t -> toLaTeX (B.text t)
           Nothing ->
             case dateParts date of
               [DateParts (y1:_), DateParts (y2:_)] ->
                 Just $ literal (T.pack (printf "%04d" y1) <> "--" <>
                        T.pack (printf "%04d" y2))
               [DateParts (y1:_)] ->
                 Just $ literal (T.pack (printf "%04d" y1))
               _ -> Nothing
       _ -> Nothing

  toMonth 1 = "jan"
  toMonth 2 = "feb"
  toMonth 3 = "mar"
  toMonth 4 = "apr"
  toMonth 5 = "may"
  toMonth 6 = "jun"
  toMonth 7 = "jul"
  toMonth 8 = "aug"
  toMonth 9 = "sep"
  toMonth 10 = "oct"
  toMonth 11 = "nov"
  toMonth 12 = "dec"
  toMonth x  = T.pack $ show x

  getMonth val =
    case val of
       DateVal date ->
         case dateParts date of
           [DateParts (_:m1:_), DateParts (_:m2:_)] ->
             Just $ literal (toMonth m1 <> "--" <> toMonth m2)
           [DateParts (_:m1:_)] -> Just $ literal (toMonth m1)
           _ -> Nothing
       _ -> Nothing

  getContentsFor :: Text -> Maybe (Doc Text)
  getContentsFor "type" =
    getVariableAsText "genre" >>=
       \case
          "mathesis"  -> Just "mastersthesis"
          "phdthesis" -> Just "phdthesis"
          _           -> Nothing
  getContentsFor "entrysubtype" = literal <$> mbSubtype
  getContentsFor "journal"
    | bibtexType `elem` ["article", "periodical", "suppperiodical", "review"]
      = getVariable "container-title" >>= toLaTeX . valToInlines
    | otherwise = Nothing
  getContentsFor "booktitle"
    | bibtexType `elem`
       ["inbook","incollection","inproceedings","inreference","bookinbook"]
    = (getVariable "volume-title" <|> getVariable "container-title")
                               >>= toLaTeX . valToInlines
    | otherwise = Nothing
  getContentsFor "series" = getVariable "collection-title"
                               >>= toLaTeX . valToInlines
  getContentsFor "address" = getVariable "publisher-place"
                               >>= toLaTeX . valToInlines
  getContentsFor "date"  = getVariable "issued" >>= toLaTeX . valToInlines
  getContentsFor "eventdate" = getVariable "event-date" >>= toLaTeX . valToInlines
  getContentsFor "urldate"  = getVariable "accessed" >>= toLaTeX . valToInlines
  getContentsFor "year"  = getVariable "issued" >>= getYear
  getContentsFor "month"  = getVariable "issued" >>= getMonth
  getContentsFor "pages"  = getVariable "page" >>= toLaTeX . valToInlines
  getContentsFor "pagetotal" = getVariable "number-of-pages"
                                  >>= toLaTeX . valToInlines
  getContentsFor "langid"  = getVariable "language" >>= toLaTeX . valToInlines
  getContentsFor "number" = (getVariable "number"
                         <|> getVariable "collection-number"
                         <|> getVariable "issue") >>= toLaTeX . valToInlines

  getContentsFor x = getVariable x >>=
    if isURL x
       then Just . literal . stringify . valToInlines
       else toLaTeX .
            (if x == "title"
                then titlecase
                else id) .
            valToInlines

  isURL x = x `elem` ["url","doi","issn","isbn"]

  renderFields = mconcat . intersperse ("," <> cr) . mapMaybe renderField

defaultLang :: Lang
defaultLang = Lang "en" Nothing (Just "US") [] [] []

-- a map of bibtex "string" macros
type StringMap = Map.Map Text Text

type BibParser = Parsec Sources (Lang, StringMap)

data Item = Item{ identifier :: Text
                , sourcePos  :: SourcePos
                , entryType  :: Text
                , fields     :: Map.Map Text Text
                }
                deriving (Show, Ord, Eq)

itemToReference :: Locale -> Variant -> Item -> BibParser (Reference Inlines)
itemToReference locale variant item = do
  setPosition (sourcePos item)
  bib item $ do
    let lang = fromMaybe defaultLang $ localeLanguage locale
    modify $ \st -> st{ localeLang = lang,
                        untitlecase = langLanguage lang == "en" }

    id' <- asks identifier
    otherIds <- (Just <$> getRawField "ids")
                  <|> return Nothing
    (reftype, genre) <- getTypeAndGenre
    -- hyphenation:
    let getLangId = do
             langid <- T.strip . T.toLower <$> getRawField "langid"
             idopts <- T.strip . T.toLower . stringify <$>
                           getField "langidopts" <|> return ""
             case (langid, idopts) of
                  ("english","variant=british")    -> return "british"
                  ("english","variant=american")   -> return "american"
                  ("english","variant=us")         -> return "american"
                  ("english","variant=usmax")      -> return "american"
                  ("english","variant=uk")         -> return "british"
                  ("english","variant=australian") -> return "australian"
                  ("english","variant=newzealand") -> return "newzealand"
                  (x,_)                            -> return x
    hyphenation <- (Just . toIETF . T.toLower <$>
                     (getLangId <|> getRawField "hyphenation"))
                  <|> return Nothing
    modify $ \s -> s{ untitlecase = untitlecase s &&
                                      case hyphenation of
                                        Just x ->
                                          "en-" `T.isPrefixOf` x || x == "en"
                                        _ -> True }


    opts <- (parseOptions <$> getRawField "options") <|> return []

    et <- asks entryType

    -- titles
    let isArticle = et `elem`
                     ["article", "periodical", "suppperiodical", "review"]
    let isPeriodical = et == "periodical"
    let isChapterlike = et `elem`
           ["inbook","incollection","inproceedings","inreference","bookinbook"]

    let getFieldMaybe f = (Just <$> getField f) <|> return Nothing

    -- names
    let getNameList' f = Just <$>
         getNameList opts f

    author' <- getNameList' "author" <|> return Nothing
    containerAuthor' <- getNameList' "bookauthor" <|> return Nothing
    translator' <- getNameList' "translator" <|> return Nothing
    editortype <- getRawField "editortype" <|> return mempty
    editor'' <- getNameList' "editor" <|> return Nothing
    director'' <- getNameList' "director" <|> return Nothing
    let (editor', director') = case editortype of
                                    "director" -> (Nothing, editor'')
                                    _          -> (editor'', director'')
    -- FIXME: add same for editora, editorb, editorc

    -- dates
    issued' <- (Just <$> (getDate "date" <|> getOldDate mempty)) <|>
               return Nothing
    eventDate' <- (Just <$> (getDate "eventdate" <|> getOldDate "event")) <|>
                   return Nothing
    origDate' <- (Just <$> (getDate "origdate" <|> getOldDate "orig")) <|>
                   return Nothing
    accessed' <- (Just <$> (getDate "urldate" <|> getOldDate "url")) <|>
                    return Nothing

    -- locators
    pages' <- getFieldMaybe "pages"
    volume' <- getFieldMaybe "volume"
    part' <- getFieldMaybe "part"
    volumes' <- getFieldMaybe "volumes"
    pagetotal' <- getFieldMaybe "pagetotal"
    chapter' <- getFieldMaybe "chapter"
    edition' <- getFieldMaybe "edition"
    version' <- getFieldMaybe "version"
    (number', collectionNumber', issue') <-
       (getField "number" >>= \x ->
         if et `elem` ["book","collection","proceedings","reference",
                       "mvbook","mvcollection","mvproceedings", "mvreference",
                       "bookinbook","inbook", "incollection","inproceedings",
                       "inreference", "suppbook","suppcollection"]
         then return (Nothing, Just x, Nothing)
         else if isArticle
              then (getField "issue" >>= \y ->
                      return (Nothing, Nothing, Just $ concatWith ',' [x,y]))
                 <|> return (Nothing, Nothing, Just x)
              else return (Just x, Nothing, Nothing))
        <|> return (Nothing, Nothing, Nothing)

    -- titles
    hasMaintitle <- (True <$ getRawField "maintitle") <|> return False

    title' <- Just <$>
              ((guard isPeriodical >> getTitle "issuetitle")
              <|> (guard hasMaintitle >>
                   guard (not isChapterlike) >>
                   getTitle "maintitle")
              <|> getTitle "title")
              <|> return Nothing

    subtitle' <- (guard isPeriodical >> getTitle "issuesubtitle")
                  <|> (guard hasMaintitle >>
                       guard (not isChapterlike) >>
                       getTitle "mainsubtitle")
                  <|> getTitle "subtitle"
                  <|> return mempty
    titleaddon' <- (guard hasMaintitle >>
                     guard (not isChapterlike) >>
                     getTitle "maintitleaddon")
                    <|> getTitle "titleaddon"
                    <|> return mempty

    volumeTitle' <- Just <$>
                    ((guard hasMaintitle >>
                      guard (not isChapterlike) >>
                      getTitle "title")
                     <|> (guard hasMaintitle >>
                          guard isChapterlike >>
                          getTitle "booktitle"))
                    <|> return Nothing
    volumeSubtitle' <- (guard hasMaintitle >>
                        guard (not isChapterlike) >>
                        getTitle "subtitle")
                       <|> (guard hasMaintitle >>
                            guard isChapterlike >>
                            getTitle "booksubtitle")
                       <|> return mempty
    volumeTitleAddon' <- (guard hasMaintitle >>
                          guard (not isChapterlike) >>
                          getTitle "titleaddon")
                         <|> (guard hasMaintitle >>
                              guard isChapterlike >>
                              getTitle "booktitleaddon")
                         <|> return mempty

    containerTitle' <- Just <$>
                       ((guard isPeriodical >> getPeriodicalTitle "title")
                       <|> (guard isChapterlike >> getTitle "maintitle")
                       <|> (guard isChapterlike >> getTitle "booktitle")
                       <|> getPeriodicalTitle "journaltitle"
                       <|> getPeriodicalTitle "journal")
                       <|> return Nothing
    containerSubtitle' <- (guard isPeriodical >> getPeriodicalTitle "subtitle")
                          <|> (guard isChapterlike >> getTitle "mainsubtitle")
                          <|> (guard isChapterlike >> getTitle "booksubtitle")
                          <|> getPeriodicalTitle "journalsubtitle"
                          <|> return mempty
    containerTitleAddon' <- (guard isPeriodical >>
                             getPeriodicalTitle "titleaddon")
                            <|> (guard isChapterlike >>
                                 getTitle "maintitleaddon")
                            <|> (guard isChapterlike >>
                                 getTitle "booktitleaddon")
                            <|> return mempty
    containerTitleShort' <- Just <$>
                            ((guard isPeriodical >>
                              guard (not hasMaintitle) >>
                              getField "shorttitle")
                            <|> getPeriodicalTitle "shortjournal")
                           <|> return Nothing

    -- change numerical series title to e.g. 'series 3'
    let fixSeriesTitle [Str xs] | isNumber xs =
          [Str (ordinalize locale xs), Space, Str (resolveKey' lang "jourser")]
        fixSeriesTitle xs = xs

    seriesTitle' <- (Just . B.fromList . fixSeriesTitle . B.toList
                       <$> getTitle "series") <|>
                    return Nothing
    shortTitle' <- (Just <$> (guard (not hasMaintitle || isChapterlike) >>
                              getTitle "shorttitle"))
                 <|> (if (subtitle' /= mempty || titleaddon' /= mempty) &&
                          not hasMaintitle
                          then getShortTitle False "title"
                          else getShortTitle True  "title")
                 <|> return Nothing

    eventTitle' <- Just <$> getTitle "eventtitle" <|> return Nothing
    origTitle' <- Just <$> getTitle "origtitle" <|> return Nothing

    -- publisher
    pubfields <- mapM (\f -> Just `fmap`
                         (if variant == Bibtex || f == "howpublished"
                          then getField f
                          else getLiteralList' f)
                        <|> return Nothing)
           ["school","institution","organization", "howpublished","publisher"]
    let publisher' = case catMaybes pubfields of
                       [] -> Nothing
                       xs -> Just $ concatWith ';' xs
    origpublisher' <- (Just <$> getField "origpublisher") <|> return Nothing

    -- places
    venue' <- (Just <$> getField "venue") <|> return Nothing
    address' <- Just <$>
                  (if variant == Bibtex
                      then getField "address"
                      else getLiteralList' "address"
                         <|> (guard (et /= "patent") >>
                              getLiteralList' "location"))
                <|> return Nothing
    origLocation' <- Just <$>
                  (if variant == Bibtex
                      then getField "origlocation"
                      else getLiteralList' "origlocation")
                    <|> return Nothing
    jurisdiction' <- if reftype == "patent"
                     then Just <$>
                        (concatWith ';' . map (resolveKey lang) <$>
                             getLiteralList "location") <|> return Nothing
                     else return Nothing

    -- url, doi, isbn, etc.:
    -- note that with eprinttype = arxiv, we take eprint to be a partial url
    -- archivePrefix is an alias for eprinttype
    url' <- (guard (et == "online" || lookup "url" opts /= Just "false")
             >> Just <$> getRawField "url")
         <|> (do etype <- getRawField "eprinttype"
                 eprint <- getRawField "eprint"
                 let baseUrl =
                       case T.toLower etype of
                         "arxiv"       -> "https://arxiv.org/abs/"
                         "jstor"       -> "https://www.jstor.org/stable/"
                         "pubmed"      -> "https://www.ncbi.nlm.nih.gov/pubmed/"
                         "googlebooks" -> "https://books.google.com?id="
                         _             -> ""
                 if T.null baseUrl
                    then mzero
                    else return $ Just $ baseUrl <> eprint)
         <|> return Nothing
    doi' <- (guard (lookup "doi" opts /= Just "false") >>
             Just <$> getRawField "doi")
           <|> return Nothing
    isbn' <- Just <$> getRawField "isbn" <|> return Nothing
    issn' <- Just <$> getRawField "issn" <|> return Nothing
    pmid' <- Just <$> getRawField  "pmid" <|> return Nothing
    pmcid' <- Just <$> getRawField "pmcid" <|> return Nothing
    callNumber' <- Just <$> getRawField "library" <|> return Nothing

    -- notes
    annotation' <- Just <$>
                   (getField "annotation" <|> getField "annote")
                     <|> return Nothing
    abstract' <- Just <$> getField "abstract" <|> return Nothing
    keywords' <- Just <$> getField "keywords" <|> return Nothing
    note' <- if et == "periodical"
             then return Nothing
             else Just <$> getField "note" <|> return Nothing
    addendum' <- if variant == Bibtex
                    then return Nothing
                    else Just <$> getField "addendum"
                 <|> return Nothing
    pubstate' <- (  (Just . resolveKey lang <$> getField "pubstate")
                  <|> case dateLiteral <$> issued' of
                           Just (Just "forthcoming") ->
                             return $ Just $ B.str "forthcoming"
                           _ -> return Nothing
                   )




    let addField (_, Nothing) = id
        addField (f, Just x)  = Map.insert f x
    let vars = foldr addField mempty
                [ ("other-ids", TextVal <$> otherIds)
                , ("genre", TextVal <$> genre)
                , ("language", TextVal <$> hyphenation)
                -- dates
                , ("accessed", DateVal <$> accessed')
                , ("event-date", DateVal <$> eventDate')
                , ("issued", DateVal <$> issued')
                , ("original-date", DateVal <$> origDate')
                -- names
                , ("author", NamesVal <$> author')
                , ("editor", NamesVal <$> editor')
                , ("translator", NamesVal <$> translator')
                , ("director", NamesVal <$> director')
                , ("container-author", NamesVal <$> containerAuthor')
                -- locators
                , ("page", FancyVal . Walk.walk convertEnDash <$> pages')
                , ("number-of-pages", FancyVal <$> pagetotal')
                , ("volume", case (volume', part') of
                               (Nothing, Nothing) -> Nothing
                               (Just v, Nothing) -> Just $ FancyVal v
                               (Nothing, Just p) -> Just $ FancyVal p
                               (Just v, Just p)  ->
                                 Just $ FancyVal $ v <> B.str "." <> p)
                , ("number-of-volumes", FancyVal <$> volumes')
                , ("chapter-number", FancyVal <$> chapter')
                , ("edition", FancyVal <$> edition')
                , ("version", FancyVal <$> version')
                , ("number", FancyVal <$> number')
                , ("collection-number", FancyVal <$> collectionNumber')
                , ("issue", FancyVal <$> issue')
                -- title
                , ("original-title", FancyVal <$> origTitle')
                , ("event", FancyVal <$> eventTitle')
                , ("title", case title' of
                              Just t -> Just $ FancyVal $
                                         concatWith '.' [
                                             concatWith ':' [t, subtitle']
                                           , titleaddon' ]
                              Nothing -> Nothing)
                , ("volume-title",
                            case volumeTitle' of
                              Just t -> Just $ FancyVal $
                                         concatWith '.' [
                                             concatWith ':' [t, volumeSubtitle']
                                           , volumeTitleAddon' ]
                              Nothing -> Nothing)
                , ("container-title",
                            case containerTitle' of
                              Just t -> Just $ FancyVal $
                                         concatWith '.' [
                                             concatWith ':' [t,
                                               containerSubtitle']
                                           , containerTitleAddon' ]
                              Nothing -> Nothing)
                , ("container-title-short", FancyVal <$> containerTitleShort')
                , ("collection-title", FancyVal <$> seriesTitle')
                , ("title-short", FancyVal <$> shortTitle')
                -- publisher
                , ("publisher", FancyVal <$> publisher')
                , ("original-publisher", FancyVal <$> origpublisher')
                -- places
                , ("jurisdiction", FancyVal <$> jurisdiction')
                , ("event-place",  FancyVal <$> venue')
                , ("publisher-place", FancyVal <$> address')
                , ("original-publisher-place", FancyVal <$> origLocation')
                -- urls
                , ("url", TextVal <$> url')
                , ("doi", TextVal <$> doi')
                , ("isbn", TextVal <$> isbn')
                , ("issn", TextVal <$> issn')
                , ("pmcid", TextVal <$> pmcid')
                , ("pmid", TextVal <$> pmid')
                , ("call-number", TextVal <$> callNumber')
                -- notes
                , ("note", case catMaybes [note', addendum'] of
                             [] -> Nothing
                             xs -> return $ FancyVal $ concatWith '.' xs)
                , ("annote", FancyVal <$> annotation')
                , ("abstract", FancyVal <$> abstract')
                , ("keyword", FancyVal <$> keywords')
                , ("status", FancyVal <$> pubstate')
                ]
    return $ Reference
      { referenceId             = ItemId id'
      , referenceType           = reftype
      , referenceDisambiguation = Nothing
      , referenceVariables      = vars }


bib :: Item -> Bib a -> BibParser a
bib entry m = fst <$> evalRWST m entry (BibState True defaultLang)

resolveCrossRefs :: Variant -> [Item] -> [Item]
resolveCrossRefs variant entries =
  map (resolveCrossRef variant entries) entries

resolveCrossRef :: Variant -> [Item] -> Item -> Item
resolveCrossRef variant entries entry =
  Map.foldrWithKey go entry (fields entry)
  where go key val entry' =
          if key == "crossref" || key == "xdata"
          then entry'{ fields = fields entry' <>
                          Map.fromList (getXrefFields variant
                                        entry entries val) }
          else entry'

getXrefFields :: Variant -> Item -> [Item] -> Text -> [(Text, Text)]
getXrefFields variant baseEntry entries keys = do
  let keys' = splitKeys keys
  xrefEntry <- [e | e <- entries, identifier e `elem` keys']
  (k, v) <- Map.toList $ fields xrefEntry
  if k == "crossref" || k == "xdata"
     then do
       xs <- mapM (getXrefFields variant baseEntry entries)
                   (splitKeys v)
       (x, y) <- xs
       guard $ isNothing $ Map.lookup x $ fields xrefEntry
       return (x, y)
     else do
       k' <- case variant of
               Bibtex -> return k
               Biblatex -> transformKey
                            (entryType xrefEntry) (entryType baseEntry) k
       guard $ isNothing $ Map.lookup k' $ fields baseEntry
       return (k',v)



data BibState = BibState{
           untitlecase    :: Bool
         , localeLang     :: Lang
         }

type Bib = RWST Item () BibState BibParser

blocksToInlines :: [Block] -> Inlines
blocksToInlines bs =
  case bs of
       [Plain xs] -> B.fromList xs
       [Para  xs] -> B.fromList xs
       _          -> B.fromList $ Walk.query (:[]) bs

adjustSpans :: Lang -> Inline -> Inline
adjustSpans lang (Span ("",[],[("bibstring",s)]) _) = Str $ resolveKey' lang s
adjustSpans _ SoftBreak = Space
adjustSpans _ x = x

latex' :: Text -> Bib [Block]
latex' t = do
  lang <- gets localeLang
  case parseLaTeX lang t of
    Left _   -> mzero
    Right bs -> return bs

parseLaTeX :: Lang -> Text -> Either PandocError [Block]
parseLaTeX lang t =
  case runPure (readLaTeX
                def{ readerExtensions =
                      extensionsFromList [Ext_raw_tex, Ext_smart] } t) of
    Left e              -> Left e
    Right (Pandoc _ bs) -> Right $ Walk.walk (adjustSpans lang) bs

latex :: Text -> Bib Inlines
latex = fmap blocksToInlines . latex' . T.strip

bibEntries :: BibParser [Item]
bibEntries = do
  skipMany nonEntry
  many (bibItem <* skipMany nonEntry)
 where nonEntry = bibSkip <|>
                  comment <|>
                  try (char '@' >>
                       (bibComment <|> bibPreamble <|> bibString))

bibSkip :: BibParser ()
bibSkip = skipMany1 (satisfy (\c -> c /='@' && c /='%'))

comment :: BibParser ()
comment = char '%' *> void anyLine

bibComment :: BibParser ()
bibComment = do
  cistring "comment"
  spaces'
  void inBraces <|> bibSkip <|> return ()

bibPreamble :: BibParser ()
bibPreamble = do
  cistring "preamble"
  spaces'
  void inBraces

bibString :: BibParser ()
bibString = do
  cistring "string"
  spaces'
  char '{'
  spaces'
  (k,v) <- entField
  char '}'
  updateState (\(l,m) -> (l, Map.insert k v m))
  return ()

take1WhileP :: Monad m => (Char -> Bool) -> ParsecT Sources u m Text
take1WhileP f = T.pack <$> many1 (satisfy f)

inBraces :: BibParser Text
inBraces = do
  char '{'
  res <- manyTill
         (  take1WhileP (\c -> c /= '{' && c /= '}' && c /= '\\')
        <|> (char '\\' >> T.cons '\\' . T.singleton <$> anyChar)
        <|> (braced <$> inBraces)
         ) (char '}')
  return $ T.concat res

braced :: Text -> Text
braced = T.cons '{' . flip T.snoc '}'

inQuotes :: BibParser Text
inQuotes = do
  char '"'
  T.concat <$> manyTill
             ( take1WhileP (\c -> c /= '{' && c /= '"' && c /= '\\')
               <|> (char '\\' >> T.cons '\\' . T.singleton <$> anyChar)
               <|> braced <$> inBraces
            ) (char '"')

fieldName :: BibParser Text
fieldName = resolveAlias . T.toLower
  <$> take1WhileP (\c ->
         isAlphaNum c || c == '-' || c == '_' || c == ':' || c == '+')

isBibtexKeyChar :: Char -> Bool
isBibtexKeyChar c =
  isAlphaNum c || c `elem` (".:;?!`'()$/*@_+=-[]*&" :: [Char])

spaces' :: BibParser ()
spaces' = skipMany (void (satisfy isSpace) <|> comment)

bibItem :: BibParser Item
bibItem = do
  char '@'
  pos <- getPosition
  enttype <- T.toLower <$> take1WhileP isLetter
  spaces'
  char '{'
  spaces'
  entid <- take1WhileP isBibtexKeyChar
  spaces'
  char ','
  spaces'
  entfields <- entField `sepEndBy` (char ',' >> spaces')
  spaces'
  char '}'
  return $ Item entid pos enttype (Map.fromList entfields)

entField :: BibParser (Text, Text)
entField = do
  k <- fieldName
  spaces'
  char '='
  spaces'
  vs <- (expandString <|> inQuotes <|> inBraces <|> rawWord) `sepBy`
            try (spaces' >> char '#' >> spaces')
  spaces'
  return (k, T.concat vs)

resolveAlias :: Text -> Text
resolveAlias "archiveprefix" = "eprinttype"
resolveAlias "primaryclass" = "eprintclass"
resolveAlias s = s

rawWord :: BibParser Text
rawWord = take1WhileP isAlphaNum

expandString :: BibParser Text
expandString = do
  k <- fieldName
  (lang, strs) <- getState
  case Map.lookup k strs of
       Just v  -> return v
       Nothing -> return $ resolveKey' lang k

cistring :: Text -> BibParser Text
cistring s = try (go s)
 where go t = case T.uncons t of
         Nothing     -> return ""
         Just (c,cs) -> do
           x <- char (toLower c) <|> char (toUpper c)
           xs <- go cs
           return (T.cons x xs)

splitKeys :: Text -> [Text]
splitKeys = filter (not . T.null) . T.split (\c -> c == ' ' || c == ',')

-- Biblatex Localization Keys (see Biblatex manual)
-- Currently we only map a subset likely to be used in Biblatex *databases*
-- (in fields such as `type`, and via `\bibstring{}` commands).

parseMonth :: Text -> Maybe Int
parseMonth s =
  case T.toLower s of
         "jan" -> Just 1
         "feb" -> Just 2
         "mar" -> Just 3
         "apr" -> Just 4
         "may" -> Just 5
         "jun" -> Just 6
         "jul" -> Just 7
         "aug" -> Just 8
         "sep" -> Just 9
         "oct" -> Just 10
         "nov" -> Just 11
         "dec" -> Just 12
         _     -> readMay (T.unpack s)

notFound :: Text -> Bib a
notFound f = Prelude.fail $ T.unpack f ++ " not found"

getField :: Text -> Bib Inlines
getField f = do
  fs <- asks fields
  case Map.lookup f fs of
       Just x  -> latex x
       Nothing -> notFound f


getPeriodicalTitle :: Text -> Bib Inlines
getPeriodicalTitle f = do
  ils <- getField f
  return ils

protectCase :: (Inlines -> Inlines) -> (Inlines -> Inlines)
protectCase f = Walk.walk unprotect . f . Walk.walk protect
 where
  protect (Span ("",[],[]) xs) = Span ("",["nocase"],[]) xs
  protect  x = x
  unprotect (Span ("",["nocase"],[]) xs)
    | hasLowercaseWord xs = Span ("",["nocase"],[]) xs
    | otherwise           = Span ("",[],[]) xs
  unprotect x = x
  hasLowercaseWord = any startsWithLowercase . splitStrWhen isPunctuation
  startsWithLowercase (Str (T.uncons -> Just (x,_))) = isLower x
  startsWithLowercase _           = False

unTitlecase :: Maybe Lang -> Inlines -> Inlines
unTitlecase mblang = protectCase (addTextCase mblang SentenceCase)

getTitle :: Text -> Bib Inlines
getTitle f = do
  ils <- getField f
  utc <- gets untitlecase
  lang <- gets localeLang
  let ils' =
        if f == "series"
           then resolveKey lang ils
           else ils
  let processTitle = if utc then unTitlecase (Just lang) else id
  return $ processTitle ils'

getShortTitle :: Bool -> Text -> Bib (Maybe Inlines)
getShortTitle requireColon f = do
  ils <- splitStrWhen (==':') . B.toList <$> getTitle f
  if not requireColon || containsColon ils
     then return $ Just $ B.fromList $ upToColon ils
     else return Nothing

containsColon :: [Inline] -> Bool
containsColon xs = Str ":" `elem` xs

upToColon :: [Inline] -> [Inline]
upToColon xs = takeWhile (/= Str ":") xs

isNumber :: Text -> Bool
isNumber t = case T.uncons t of
  Just ('-', ds) -> T.all isDigit ds
  Just _         -> T.all isDigit t
  Nothing        -> False

getDate :: Text -> Bib Date
getDate f = do
  -- the ~ can used for approx dates, but the latex reader
  -- parses this as a nonbreaking space, so we need to convert it back!
  let nbspToTilde '\160' = '~'
      nbspToTilde c      = c
  mbd <- rawDateEDTF . T.map nbspToTilde <$> getRawField f
  case mbd of
    Nothing -> Prelude.fail "expected date"
    Just d  -> return d

-- A negative (BC) year might be written with -- or --- in bibtex:
fixLeadingDash :: Text -> Text
fixLeadingDash t = case T.uncons t of
  Just (c, ds) | (c == '–' || c == '—') && firstIsDigit ds -> T.cons '–' ds
  _ -> t
 where firstIsDigit = maybe False (isDigit . fst) . T.uncons

getOldDate :: Text -> Bib Date
getOldDate prefix = do
  year' <- (readMay . T.unpack . fixLeadingDash . stringify
              <$> getField (prefix <> "year")) <|> return Nothing
  month' <- (parseMonth <$> getRawField (prefix <> "month"))
            <|> return Nothing
  day' <- (readMay . T.unpack <$> getRawField (prefix <> "day"))
          <|> return Nothing
  endyear' <- (readMay . T.unpack . fixLeadingDash . stringify
              <$> getField (prefix <> "endyear")) <|> return Nothing
  endmonth' <- (parseMonth . stringify
                 <$> getField (prefix <> "endmonth")) <|> return Nothing
  endday' <- (readMay . T.unpack . stringify <$>
                 getField (prefix <> "endday")) <|> return Nothing
  let toDateParts (y', m', d') =
              DateParts $
                 case y' of
                   Nothing -> []
                   Just y  ->
                     case m' of
                       Nothing -> [y]
                       Just m  ->
                         case d' of
                           Nothing -> [y,m]
                           Just d  -> [y,m,d]
  let dateparts = filter (\x -> x /= DateParts [])
                  $ map toDateParts [(year',month',day'),
                                     (endyear',endmonth',endday')]
  literal' <- if null dateparts
                 then Just <$> getRawField (prefix <> "year")
                 else return Nothing
  return $
    Date { dateParts = dateparts
         , dateCirca = False
         , dateSeason = Nothing
         , dateLiteral = literal' }

getRawField :: Text -> Bib Text
getRawField f = do
  fs <- asks fields
  case Map.lookup f fs of
       Just x  -> return x
       Nothing -> notFound f

getLiteralList :: Text -> Bib [Inlines]
getLiteralList f = do
  fs <- asks fields
  case Map.lookup f fs of
       Just x  -> latex' x >>= toLiteralList
       Nothing -> notFound f

-- separates items with semicolons
getLiteralList' :: Text -> Bib Inlines
getLiteralList' f = do
  fs <- asks fields
  case Map.lookup f fs of
    Just x    -> do
      x' <- latex' x
      case x' of
        [Para xs]  ->
          return $ B.fromList
                 $ intercalate [Str ";", Space]
                 $ splitByAnd xs
        [Plain xs] ->
          return $ B.fromList
                 $ intercalate [Str ";", Space]
                 $ splitByAnd xs
        _          -> mzero
    Nothing   -> notFound f

splitByAnd :: [Inline] -> [[Inline]]
splitByAnd = splitOn [Space, Str "and", Space]

toLiteralList :: [Block] -> Bib [Inlines]
toLiteralList [Para xs] =
  return $ map B.fromList $ splitByAnd xs
toLiteralList [Plain xs] = toLiteralList [Para xs]
toLiteralList _ = mzero

concatWith :: Char -> [Inlines] -> Inlines
concatWith sep = foldl' go mempty
  where go :: Inlines -> Inlines -> Inlines
        go accum s
          | s == mempty = accum
          | otherwise   =
              case Seq.viewr (B.unMany accum) of
                     Seq.EmptyR -> s
                     _ Seq.:> Str x
                       | not (T.null x) &&
                         T.last x `elem` ("!?.,:;" :: String)
                                    -> accum <> B.space <> s
                     _ -> accum <> B.str (T.singleton sep) <>
                                                B.space <> s


parseOptions :: Text -> [(Text, Text)]
parseOptions = map breakOpt . T.splitOn ","
  where breakOpt x = case T.break (=='=') x of
                          (w,v) -> (T.toLower $ T.strip w,
                                    T.toLower $ T.strip $ T.drop 1 v)

optionSet :: Text -> [(Text, Text)] -> Bool
optionSet key opts = case lookup key opts of
                      Just "true" -> True
                      Just s      -> s == mempty
                      _           -> False

getNameList :: [(Text, Text)] -> Text -> Bib [Name]
getNameList opts  f = do
  fs <- asks fields
  case Map.lookup f fs of
       Just x  -> latexNames nameopts x
       Nothing -> notFound f
 where
  nameopts = NameOpts{
                 nameOptsPrefixIsNonDroppingParticle = optionSet "useprefix" opts,
                 nameOptsUseJuniorComma = optionSet "juniorcomma" opts}

toNameList :: NameOpts -> [Block] -> Bib [Name]
toNameList opts [Para xs] =
  filter (/= emptyName) <$> mapM (toName opts . addSpaceAfterPeriod)
                                    (splitByAnd xs)
toNameList opts [Plain xs] = toNameList opts [Para xs]
toNameList _ _ = mzero

latexNames :: NameOpts -> Text -> Bib [Name]
latexNames opts t = latex' (T.strip t) >>= toNameList opts

-- see issue 392 for motivation.  We want to treat
-- "J.G. Smith" and "J. G. Smith" the same.
addSpaceAfterPeriod :: [Inline] -> [Inline]
addSpaceAfterPeriod = go . splitStrWhen (=='.')
  where
    go [] = []
    go (Str (T.unpack -> [c]):Str ".":Str (T.unpack -> [d]):xs)
      | isLetter d
      , isLetter c
      , isUpper c
      , isUpper d
        = Str (T.singleton c):Str ".":Space:go (Str (T.singleton d):xs)
    go (x:xs) = x:go xs

ordinalize :: Locale -> Text -> Text
ordinalize locale n =
  let terms = localeTerms locale
      pad0 t = case T.length t of
                 0 -> "00"
                 1 -> "0" <> t
                 _ -> t
   in case Map.lookup ("ordinal-" <> pad0 n) terms <|>
           Map.lookup "ordinal" terms of
        Nothing    -> n
        Just []    -> n
        Just (t:_) -> n <> snd t

getTypeAndGenre :: Bib (Text, Maybe Text)
getTypeAndGenre = do
  lang <- gets localeLang
  et <- asks entryType
  reftype' <- resolveKey' lang <$> getRawField "type"
         <|> return mempty
  st <- getRawField "entrysubtype" <|> return mempty
  isEvent <- (True <$ (getRawField "eventdate"
                     <|> getRawField "eventtitle"
                     <|> getRawField "venue")) <|> return False
  let reftype =
        case et of
           "article"
             | st == "magazine"  -> "article-magazine"
             | st == "newspaper" -> "article-newspaper"
             | otherwise         -> "article-journal"
           "book"                -> "book"
           "booklet"             -> "pamphlet"
           "bookinbook"          -> "chapter"
           "collection"          -> "book"
           "dataset"             -> "dataset"
           "electronic"          -> "webpage"
           "inbook"              -> "chapter"
           "incollection"        -> "chapter"
           "inreference"         -> "entry-encyclopedia"
           "inproceedings"       -> "paper-conference"
           "manual"              -> "book"
           "mastersthesis"       -> "thesis"
           "misc"                -> ""
           "mvbook"              -> "book"
           "mvcollection"        -> "book"
           "mvproceedings"       -> "book"
           "mvreference"         -> "book"
           "online"              -> "webpage"
           "patent"              -> "patent"
           "periodical"
             | st == "magazine"  -> "article-magazine"
             | st == "newspaper" -> "article-newspaper"
             | otherwise         -> "article-journal"
           "phdthesis"           -> "thesis"
           "proceedings"         -> "book"
           "reference"           -> "book"
           "report"              -> "report"
           "software"            -> "software"
           "suppbook"            -> "chapter"
           "suppcollection"      -> "chapter"
           "suppperiodical"
             | st == "magazine"  -> "article-magazine"
             | st == "newspaper" -> "article-newspaper"
             | otherwise         -> "article-journal"
           "techreport"          -> "report"
           "thesis"              -> "thesis"
           "unpublished"         -> if isEvent then "speech" else "manuscript"
           "www"                 -> "webpage"
           -- biblatex, "unsupported"
           "artwork"             -> "graphic"
           "audio"               -> "song"    -- for audio *recordings*
           "commentary"          -> "book"
           "image"               -> "graphic"   -- or "figure" ?
           "jurisdiction"        -> "legal_case"
           "legislation"         -> "legislation"  -- or "bill" ?
           "legal"               -> "treaty"
           "letter"              -> "personal_communication"
           "movie"               -> "motion_picture"
           "music"               -> "song"        -- for musical *recordings*
           "performance"         -> "speech"
           "review"              -> "review"      -- or "review-book" ?
           "standard"            -> "legislation"
           "video"               -> "motion_picture"
           -- biblatex-apa:
           "data"                -> "dataset"
           "letters"             -> "personal_communication"
           "newsarticle"         -> "article-newspaper"
           _                     -> ""

  let refgenre =
        case et of
          "mastersthesis"  -> if T.null reftype'
                                 then Just $ resolveKey' lang "mathesis"
                                 else Just reftype'
          "phdthesis"      -> if T.null reftype'
                                 then Just $ resolveKey' lang "phdthesis"
                                 else Just reftype'
          _                -> if T.null reftype'
                                 then Nothing
                                 else Just reftype'
  return (reftype, refgenre)


-- transformKey source target key
-- derived from Appendix C of bibtex manual
transformKey :: Text -> Text -> Text -> [Text]
transformKey _ _ "ids"            = []
transformKey _ _ "crossref"       = []
transformKey _ _ "xref"           = []
transformKey _ _ "entryset"       = []
transformKey _ _ "entrysubtype"   = []
transformKey _ _ "execute"        = []
transformKey _ _ "label"          = []
transformKey _ _ "options"        = []
transformKey _ _ "presort"        = []
transformKey _ _ "related"        = []
transformKey _ _ "relatedoptions" = []
transformKey _ _ "relatedstring"  = []
transformKey _ _ "relatedtype"    = []
transformKey _ _ "shorthand"      = []
transformKey _ _ "shorthandintro" = []
transformKey _ _ "sortkey"        = []
transformKey x y "author"
  | x `elem` ["mvbook", "book"] &&
    y `elem` ["inbook", "bookinbook", "suppbook"] = ["bookauthor", "author"]
-- note: this next clause is not in the biblatex manual, but it makes
-- sense in the context of CSL conversion:
transformKey x y "author"
  | x == "mvbook" && y == "book" = ["bookauthor", "author"]
transformKey "mvbook" y z
  | y `elem` ["book", "inbook", "bookinbook", "suppbook"] = standardTrans z
transformKey x y z
  | x `elem` ["mvcollection", "mvreference"] &&
    y `elem` ["collection", "reference", "incollection", "inreference",
               "suppcollection"] = standardTrans z
transformKey "mvproceedings" y z
  | y `elem` ["proceedings", "inproceedings"] = standardTrans z
transformKey "book" y z
  | y `elem` ["inbook", "bookinbook", "suppbook"] = bookTrans z
transformKey x y z
  | x `elem` ["collection", "reference"] &&
    y `elem` ["incollection", "inreference", "suppcollection"] = bookTrans z
transformKey "proceedings" "inproceedings" z = bookTrans z
transformKey "periodical" y z
  | y `elem` ["article", "suppperiodical"] =
  case z of
       "title"          -> ["journaltitle"]
       "subtitle"       -> ["journalsubtitle"]
       "shorttitle"     -> []
       "sorttitle"      -> []
       "indextitle"     -> []
       "indexsorttitle" -> []
       _                -> [z]
transformKey _ _ x                = [x]

standardTrans :: Text -> [Text]
standardTrans z =
  case z of
       "title"          -> ["maintitle"]
       "subtitle"       -> ["mainsubtitle"]
       "titleaddon"     -> ["maintitleaddon"]
       "shorttitle"     -> []
       "sorttitle"      -> []
       "indextitle"     -> []
       "indexsorttitle" -> []
       _                -> [z]

bookTrans :: Text -> [Text]
bookTrans z =
  case z of
       "title"          -> ["booktitle"]
       "subtitle"       -> ["booksubtitle"]
       "titleaddon"     -> ["booktitleaddon"]
       "shorttitle"     -> []
       "sorttitle"      -> []
       "indextitle"     -> []
       "indexsorttitle" -> []
       _                -> [z]

resolveKey :: Lang -> Inlines -> Inlines
resolveKey lang (Many ils) = Many $ fmap go ils
  where go (Str s) = Str $ resolveKey' lang s
        go x       = x

resolveKey' :: Lang -> Text -> Text
resolveKey' lang k =
  case Map.lookup (langLanguage lang) biblatexStringMap >>=
        Map.lookup k of
    Nothing     -> k
    Just (x, _) -> either (const k) stringify $ parseLaTeX lang x

convertEnDash :: Inline -> Inline
convertEnDash (Str s) = Str (T.map (\c -> if c == '–' then '-' else c) s)
convertEnDash x       = x
