{-# LANGUAGE NoImplicitPrelude #-}
Copyright (C) 2008-2018 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
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.Highlighting
   Copyright   : Copyright (C) 2008-2018 John MacFarlane
   License     : GNU GPL, version 2 or above

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

Exports functions for syntax highlighting.

module Text.Pandoc.Highlighting ( highlightingStyles
                                , languages
                                , languagesByExtension
                                , highlight
                                , formatLaTeXInline
                                , formatLaTeXBlock
                                , styleToLaTeX
                                , formatHtmlInline
                                , formatHtmlBlock
                                , styleToCss
                                , pygments
                                , espresso
                                , zenburn
                                , tango
                                , kate
                                , monochrome
                                , breezeDark
                                , haddock
                                , Style
                                , fromListingsLanguage
                                , toListingsLanguage
                                ) where
import Prelude
import Control.Monad
import Data.Char (toLower)
import qualified Data.Map as M
import Data.Maybe (fromMaybe)
import qualified Data.Text as T
import Skylighting
import Text.Pandoc.Definition
import Text.Pandoc.Shared (safeRead)

highlightingStyles :: [(String, Style)]
highlightingStyles =
  [("pygments", pygments),
   ("tango", tango),
   ("espresso", espresso),
   ("zenburn", zenburn),
   ("kate", kate),
   ("monochrome", monochrome),
   ("breezedark", breezeDark),
   ("haddock", haddock)]

languages :: [String]
languages = [T.unpack (T.toLower (sName s)) | s <- M.elems defaultSyntaxMap]

languagesByExtension :: String -> [String]
languagesByExtension ext =
  [T.unpack (T.toLower (sName s)) | s <- syntaxesByExtension defaultSyntaxMap ext]

highlight :: SyntaxMap
          -> (FormatOptions -> [SourceLine] -> a) -- ^ Formatter
          -> Attr   -- ^ Attributes of the CodeBlock
          -> String -- ^ Raw contents of the CodeBlock
          -> Either String a
highlight syntaxmap formatter (ident, classes, keyvals) rawCode =
  let firstNum = fromMaybe 1 (safeRead (fromMaybe "1" $ lookup "startFrom" keyvals))
      fmtOpts = defaultFormatOpts{
                  startNumber = firstNum,
                  lineAnchors = any (`elem`
                        ["line-anchors", "lineAnchors"]) classes,
                  numberLines = any (`elem`
                        ["number","numberLines", "number-lines"]) classes,
                  lineIdPrefix = if null ident
                                    then mempty
                                    else T.pack (ident ++ "-") }
      tokenizeOpts = TokenizerConfig{ syntaxMap = syntaxmap
                                    , traceOutput = False }
      classes' = map T.pack classes
      rawCode' = T.pack rawCode
  in  case msum (map (`lookupSyntax` syntaxmap) classes') of
              | numberLines fmtOpts -> Right
                              $ formatter fmtOpts{ codeClasses = [],
                                                   containerClasses = classes' }
                              $ map (\ln -> [(NormalTok, ln)])
                              $ T.lines rawCode'
              | otherwise  -> Left ""
            Just syntax  ->
              formatter fmtOpts{ codeClasses =
                                   [T.toLower (sShortname syntax)],
                                  containerClasses = classes' } <$>
                tokenize tokenizeOpts syntax rawCode'

-- Functions for correlating latex listings package's language names
-- with skylighting language names:

langToListingsMap :: M.Map String String
langToListingsMap = M.fromList langsList

listingsToLangMap :: M.Map String String
listingsToLangMap = M.fromList $ map switch langsList
  where switch (a,b) = (b,a)

langsList :: [(String, String)]
langsList =

-- | Determine listings language name from skylighting language name.
toListingsLanguage :: String -> Maybe String
toListingsLanguage lang = M.lookup (map toLower lang) langToListingsMap

-- | Determine skylighting language name from listings language name.
fromListingsLanguage :: String -> Maybe String
fromListingsLanguage lang = M.lookup lang listingsToLangMap