import Text.Pandoc.Definition
import Text.Pandoc.JSON
import Text.Pandoc.Builder

main :: IO ()
main = toJSONFilter \case
  Code _ txt
    | Just _ <- enclosed '/' '/' txt ->
        Span (cls ["ipa", "ipa-broad"]) $ text' txt
    | Just _ <- enclosed '[' ']' txt ->
        Span (cls ["ipa", "ipa-narrow"]) $ text' txt
    | Just txt' <- enclosed '{' '}' txt ->
        Span (cls ["lang"]) $ text' txt'
  i -> i

cls :: [String] -> Attr
cls cs = ("", cs, [])

text' :: String -> [Inline]
text' = toList . text


enclosed :: Char -> Char -> String -> Maybe String
enclosed o c txt
  | length txt >= 2, head txt == o, last txt == c
  = Just $ init $ tail txt
enclosed _ _ _ = Nothing