{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeOperators #-}
module Text.Compdoc.Dhall where

import Composite.Aeson
import Composite.Record
import Data.Either.Validation
import Data.Void
import qualified Dhall as D
import Data.Text as T
import Text.Compdoc
import Data.Typeable
import Text.Pandoc

-- | Decode a Compdoc value.
compdocDecoder :: WriterOptions -> JsonFormat Void (Record a) -> D.InputNormalizer -> D.Decoder (Record (FContent ': a))
compdocDecoder wopts f opts =
      D.Decoder
            { D.extract = extractDoc
            , D.expected = expectedDoc
            }
      where
        docDecoder :: D.Decoder Text
        docDecoder = D.autoWith opts

        extractDoc expression =
          case D.extract docDecoder expression of
              Success x -> case readMarkdown' def { readerExtensions = pandocExtensions } wopts f x of
                Left exception   -> D.extractError (T.pack $ show exception)
                Right path       -> Success path
              Failure e        -> Failure e
        expectedDoc = D.expected docDecoder