--------------------------------------------------------------------------------
-- | Wraps pandocs bibiliography handling
--
-- In order to add a bibliography, you will need a bibliography file (e.g.
-- @.bib@) and a CSL file (@.csl@). Both need to be compiled with their
-- respective compilers ('biblioCompiler' and 'cslCompiler'). Then, you can
-- refer to these files when you use 'readPandocBiblio'. This function also
-- takes the reader options for completeness -- you can use
-- 'defaultHakyllReaderOptions' if you're unsure. If you already read the
-- source into a 'Pandoc' type and need to add processing for the bibliography,
-- you can use 'processPandocBiblio' instead.
-- 'pandocBiblioCompiler' is a convenience wrapper which works like 'pandocCompiler',
-- but also takes paths to compiled bibliography and csl files.
{-# LANGUAGE Arrows                     #-}
{-# LANGUAGE DeriveDataTypeable         #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE OverloadedStrings          #-}
module Hakyll.Web.Pandoc.Biblio
    ( CSL (..)
    , cslCompiler
    , Biblio (..)
    , biblioCompiler
    , readPandocBiblio
    , processPandocBiblio
    , pandocBiblioCompiler
    ) where


--------------------------------------------------------------------------------
import           Control.Monad                 (liftM)
import           Data.Binary                   (Binary (..))
import qualified Data.ByteString               as B
import qualified Data.ByteString.Lazy          as BL
import qualified Data.Map                      as Map
import qualified Data.Time                     as Time
import           Data.Typeable                 (Typeable)
import           Hakyll.Core.Compiler
import           Hakyll.Core.Compiler.Internal
import           Hakyll.Core.Identifier
import           Hakyll.Core.Item
import           Hakyll.Core.Writable
import           Hakyll.Web.Pandoc
import           Text.Pandoc                   (Extension (..), Pandoc,
                                                ReaderOptions (..),
                                                enableExtension)
import qualified Text.Pandoc                   as Pandoc
import qualified Text.Pandoc.Citeproc          as Pandoc (processCitations)


--------------------------------------------------------------------------------
newtype CSL = CSL {CSL -> ByteString
unCSL :: B.ByteString}
    deriving (Get CSL
[CSL] -> Put
CSL -> Put
(CSL -> Put) -> Get CSL -> ([CSL] -> Put) -> Binary CSL
forall t. (t -> Put) -> Get t -> ([t] -> Put) -> Binary t
putList :: [CSL] -> Put
$cputList :: [CSL] -> Put
get :: Get CSL
$cget :: Get CSL
put :: CSL -> Put
$cput :: CSL -> Put
Binary, Int -> CSL -> ShowS
[CSL] -> ShowS
CSL -> String
(Int -> CSL -> ShowS)
-> (CSL -> String) -> ([CSL] -> ShowS) -> Show CSL
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [CSL] -> ShowS
$cshowList :: [CSL] -> ShowS
show :: CSL -> String
$cshow :: CSL -> String
showsPrec :: Int -> CSL -> ShowS
$cshowsPrec :: Int -> CSL -> ShowS
Show, Typeable)



--------------------------------------------------------------------------------
instance Writable CSL where
    -- Shouldn't be written.
    write :: String -> Item CSL -> IO ()
write String
_ Item CSL
_ = () -> IO ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()


--------------------------------------------------------------------------------
cslCompiler :: Compiler (Item CSL)
cslCompiler :: Compiler (Item CSL)
cslCompiler = (ByteString -> CSL) -> Item ByteString -> Item CSL
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (ByteString -> CSL
CSL (ByteString -> CSL)
-> (ByteString -> ByteString) -> ByteString -> CSL
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ByteString -> ByteString
BL.toStrict) (Item ByteString -> Item CSL)
-> Compiler (Item ByteString) -> Compiler (Item CSL)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Compiler (Item ByteString)
getResourceLBS


--------------------------------------------------------------------------------
newtype Biblio = Biblio {Biblio -> ByteString
unBiblio :: B.ByteString}
    deriving (Get Biblio
[Biblio] -> Put
Biblio -> Put
(Biblio -> Put) -> Get Biblio -> ([Biblio] -> Put) -> Binary Biblio
forall t. (t -> Put) -> Get t -> ([t] -> Put) -> Binary t
putList :: [Biblio] -> Put
$cputList :: [Biblio] -> Put
get :: Get Biblio
$cget :: Get Biblio
put :: Biblio -> Put
$cput :: Biblio -> Put
Binary, Int -> Biblio -> ShowS
[Biblio] -> ShowS
Biblio -> String
(Int -> Biblio -> ShowS)
-> (Biblio -> String) -> ([Biblio] -> ShowS) -> Show Biblio
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [Biblio] -> ShowS
$cshowList :: [Biblio] -> ShowS
show :: Biblio -> String
$cshow :: Biblio -> String
showsPrec :: Int -> Biblio -> ShowS
$cshowsPrec :: Int -> Biblio -> ShowS
Show, Typeable)


--------------------------------------------------------------------------------
instance Writable Biblio where
    -- Shouldn't be written.
    write :: String -> Item Biblio -> IO ()
write String
_ Item Biblio
_ = () -> IO ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()


--------------------------------------------------------------------------------
biblioCompiler :: Compiler (Item Biblio)
biblioCompiler :: Compiler (Item Biblio)
biblioCompiler = (ByteString -> Biblio) -> Item ByteString -> Item Biblio
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (ByteString -> Biblio
Biblio (ByteString -> Biblio)
-> (ByteString -> ByteString) -> ByteString -> Biblio
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ByteString -> ByteString
BL.toStrict) (Item ByteString -> Item Biblio)
-> Compiler (Item ByteString) -> Compiler (Item Biblio)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Compiler (Item ByteString)
getResourceLBS


--------------------------------------------------------------------------------
readPandocBiblio :: ReaderOptions
                 -> Item CSL
                 -> Item Biblio
                 -> (Item String)
                 -> Compiler (Item Pandoc)
readPandocBiblio :: ReaderOptions
-> Item CSL -> Item Biblio -> Item String -> Compiler (Item Pandoc)
readPandocBiblio ReaderOptions
ropt Item CSL
csl Item Biblio
biblio Item String
item = do
  Item Pandoc
pandoc <- ReaderOptions -> Item String -> Compiler (Item Pandoc)
readPandocWith ReaderOptions
ropt Item String
item
  Item CSL -> Item Biblio -> Item Pandoc -> Compiler (Item Pandoc)
processPandocBiblio Item CSL
csl Item Biblio
biblio Item Pandoc
pandoc


--------------------------------------------------------------------------------
processPandocBiblio :: Item CSL
                    -> Item Biblio
                    -> (Item Pandoc)
                    -> Compiler (Item Pandoc)
processPandocBiblio :: Item CSL -> Item Biblio -> Item Pandoc -> Compiler (Item Pandoc)
processPandocBiblio Item CSL
csl Item Biblio
biblio Item Pandoc
item = do
    -- It's not straightforward to use the Pandoc API as of 2.11 to deal with
    -- citations, since it doesn't export many things in 'Text.Pandoc.Citeproc'.
    -- The 'citeproc' package is also hard to use.
    --
    -- So instead, we try treating Pandoc as a black box.  Pandoc can read
    -- specific csl and bilbio files based on metadata keys.
    --
    -- So we load the CSL and Biblio files and pass them to Pandoc using the
    -- ersatz filesystem.
    let Pandoc.Pandoc (Pandoc.Meta Map Text MetaValue
meta) [Block]
blocks = Item Pandoc -> Pandoc
forall a. Item a -> a
itemBody Item Pandoc
item
        cslFile :: FileInfo
cslFile = UTCTime -> ByteString -> FileInfo
Pandoc.FileInfo UTCTime
zeroTime (ByteString -> FileInfo) -> (CSL -> ByteString) -> CSL -> FileInfo
forall b c a. (b -> c) -> (a -> b) -> a -> c
. CSL -> ByteString
unCSL (CSL -> FileInfo) -> CSL -> FileInfo
forall a b. (a -> b) -> a -> b
$ Item CSL -> CSL
forall a. Item a -> a
itemBody Item CSL
csl
        bibFile :: FileInfo
bibFile = UTCTime -> ByteString -> FileInfo
Pandoc.FileInfo UTCTime
zeroTime (ByteString -> FileInfo)
-> (Biblio -> ByteString) -> Biblio -> FileInfo
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Biblio -> ByteString
unBiblio (Biblio -> FileInfo) -> Biblio -> FileInfo
forall a b. (a -> b) -> a -> b
$ Item Biblio -> Biblio
forall a. Item a -> a
itemBody Item Biblio
biblio
        addBiblioFiles :: PureState -> PureState
addBiblioFiles = \PureState
st -> PureState
st
            { stFiles :: FileTree
Pandoc.stFiles =
                String -> FileInfo -> FileTree -> FileTree
Pandoc.insertInFileTree String
"_hakyll/style.csl" FileInfo
cslFile (FileTree -> FileTree)
-> (FileTree -> FileTree) -> FileTree -> FileTree
forall b c a. (b -> c) -> (a -> b) -> a -> c
.
                String -> FileInfo -> FileTree -> FileTree
Pandoc.insertInFileTree String
"_hakyll/refs.bib" FileInfo
bibFile (FileTree -> FileTree) -> FileTree -> FileTree
forall a b. (a -> b) -> a -> b
$
                PureState -> FileTree
Pandoc.stFiles PureState
st
            }
        biblioMeta :: Meta
biblioMeta = Map Text MetaValue -> Meta
Pandoc.Meta (Map Text MetaValue -> Meta)
-> (Map Text MetaValue -> Map Text MetaValue)
-> Map Text MetaValue
-> Meta
forall b c a. (b -> c) -> (a -> b) -> a -> c
.
            Text -> MetaValue -> Map Text MetaValue -> Map Text MetaValue
forall k a. Ord k => k -> a -> Map k a -> Map k a
Map.insert Text
"csl" (Text -> MetaValue
Pandoc.MetaString Text
"_hakyll/style.csl") (Map Text MetaValue -> Map Text MetaValue)
-> (Map Text MetaValue -> Map Text MetaValue)
-> Map Text MetaValue
-> Map Text MetaValue
forall b c a. (b -> c) -> (a -> b) -> a -> c
.
            Text -> MetaValue -> Map Text MetaValue -> Map Text MetaValue
forall k a. Ord k => k -> a -> Map k a -> Map k a
Map.insert Text
"bibliography" (Text -> MetaValue
Pandoc.MetaString Text
"_hakyll/refs.bib") (Map Text MetaValue -> Meta) -> Map Text MetaValue -> Meta
forall a b. (a -> b) -> a -> b
$
            Map Text MetaValue
meta
        errOrPandoc :: Either PandocError Pandoc
errOrPandoc = PandocPure Pandoc -> Either PandocError Pandoc
forall a. PandocPure a -> Either PandocError a
Pandoc.runPure (PandocPure Pandoc -> Either PandocError Pandoc)
-> PandocPure Pandoc -> Either PandocError Pandoc
forall a b. (a -> b) -> a -> b
$ do
            (PureState -> PureState) -> PandocPure ()
Pandoc.modifyPureState PureState -> PureState
addBiblioFiles
            Pandoc -> PandocPure Pandoc
forall (m :: * -> *). PandocMonad m => Pandoc -> m Pandoc
Pandoc.processCitations (Pandoc -> PandocPure Pandoc) -> Pandoc -> PandocPure Pandoc
forall a b. (a -> b) -> a -> b
$ Meta -> [Block] -> Pandoc
Pandoc.Pandoc Meta
biblioMeta [Block]
blocks

    Pandoc
pandoc <- case Either PandocError Pandoc
errOrPandoc of
        Left  PandocError
e -> [String] -> Compiler Pandoc
forall a. [String] -> Compiler a
compilerThrow [String
"Error during processCitations: " String -> ShowS
forall a. [a] -> [a] -> [a]
++ PandocError -> String
forall a. Show a => a -> String
show PandocError
e]
        Right Pandoc
x -> Pandoc -> Compiler Pandoc
forall (m :: * -> *) a. Monad m => a -> m a
return Pandoc
x

    Item Pandoc -> Compiler (Item Pandoc)
forall (m :: * -> *) a. Monad m => a -> m a
return (Item Pandoc -> Compiler (Item Pandoc))
-> Item Pandoc -> Compiler (Item Pandoc)
forall a b. (a -> b) -> a -> b
$ (Pandoc -> Pandoc) -> Item Pandoc -> Item Pandoc
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap (Pandoc -> Pandoc -> Pandoc
forall a b. a -> b -> a
const Pandoc
pandoc) Item Pandoc
item

  where
    zeroTime :: UTCTime
zeroTime = Day -> DiffTime -> UTCTime
Time.UTCTime (Int -> Day
forall a. Enum a => Int -> a
toEnum Int
0) DiffTime
0


--------------------------------------------------------------------------------
-- | Compiles a markdown file via Pandoc. Requires the .csl and .bib files to be known to the compiler via match statements.
pandocBiblioCompiler :: String -> String -> Compiler (Item String)
pandocBiblioCompiler :: String -> String -> Compiler (Item String)
pandocBiblioCompiler String
cslFileName String
bibFileName = do
    Item CSL
csl <- Identifier -> Compiler (Item CSL)
forall a. (Binary a, Typeable a) => Identifier -> Compiler (Item a)
load (Identifier -> Compiler (Item CSL))
-> Identifier -> Compiler (Item CSL)
forall a b. (a -> b) -> a -> b
$ String -> Identifier
fromFilePath String
cslFileName
    Item Biblio
bib <- Identifier -> Compiler (Item Biblio)
forall a. (Binary a, Typeable a) => Identifier -> Compiler (Item a)
load (Identifier -> Compiler (Item Biblio))
-> Identifier -> Compiler (Item Biblio)
forall a b. (a -> b) -> a -> b
$ String -> Identifier
fromFilePath String
bibFileName
    (Item Pandoc -> Item String)
-> Compiler (Item Pandoc) -> Compiler (Item String)
forall (m :: * -> *) a1 r. Monad m => (a1 -> r) -> m a1 -> m r
liftM Item Pandoc -> Item String
writePandoc
        (Compiler (Item String)
getResourceBody Compiler (Item String)
-> (Item String -> Compiler (Item Pandoc))
-> Compiler (Item Pandoc)
forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= ReaderOptions
-> Item CSL -> Item Biblio -> Item String -> Compiler (Item Pandoc)
readPandocBiblio ReaderOptions
ropt Item CSL
csl Item Biblio
bib)
    where ropt :: ReaderOptions
ropt = ReaderOptions
defaultHakyllReaderOptions
            { -- The following option enables citation rendering
              readerExtensions :: Extensions
readerExtensions = Extension -> Extensions -> Extensions
enableExtension Extension
Ext_citations (Extensions -> Extensions) -> Extensions -> Extensions
forall a b. (a -> b) -> a -> b
$ ReaderOptions -> Extensions
readerExtensions ReaderOptions
defaultHakyllReaderOptions
            }