{-# OPTIONS_GHC -fno-warn-orphans #-}
module Hakyll.TeX.BibTeX
    ( bibtexCompiler
    , compileBibtex
    , BibEntry
    , BibTeX
    ) where

import Prolog

import Data.List qualified as L
import Hakyll
import Text.BibTeX.Entry qualified as B
import Text.BibTeX.Format qualified as BF
import Text.BibTeX.Parse qualified as B
import Text.Parsec qualified as P

import Hakyll.Parsec

type BibEntry = B.T
type BibTeX = [BibEntry]

deriving instance Generic B.T
instance Binary B.T

instance Writable B.T where
    write p = write p . fmap BF.entry

instance Writable [B.T] where
    write p = write p . fmap (fold . L.intersperse "\n" . fmap BF.entry)


compileBibtex :: (StringConv s String) => Item s -> Compiler (Item BibTeX)
compileBibtex = fmap (B.lowerCaseFieldNames <<$>>) . compileParsec_ p . fmap toSL
    where
        p = B.skippingLeadingSpace $ B.file <* P.space <* P.eof

bibtexCompiler :: Compiler (Item BibTeX)
bibtexCompiler = getResourceBody >>= compileBibtex