-- | Gemini lightwight hypertext format, mime type text/gemini,
-- see <https://geminiprotocol.net/docs/specification.gmi>
module Gemini where
import Data.List(mapAccumL,stripPrefix)
--import Html
import HtmlTags
import HtmlConOps as H

-- | Convert a text/gemini document to HTML
gemini2html =
    (:[]) . body . map (ctx DIV).snd.mapAccumL renderLine False . lines
  where
    renderLine pre l = maybe (pre,plain) toggle (stripPrefix "```" l)
      where
        toggle _ = (not pre,[])
        plain | null l = [txt " "]
              | pre    = [H.pre [txt l]]
              | take 3 l == "=> " =
                   case words l of
                     ar:url:ws-> [ctx SPAN [txt "=> ",href url [txt linktext]]]
                       where linktext | null ws = url
                                      | otherwise = unwords ws -- !!
              | take 2 l == "* " = [ul [li [txt (drop 2 l)]]] -- !!
              | take 1 l == ">" = [ctx BLOCKQUOTE [txt (tail l)]]
              | level>0 = [m0 ([H1,H2,H3] !! (level-1)) [txt l']]
              | otherwise = [txt l]
        (hashes,l') = dropWhile (==' ') <$> span (=='#') l
        level = min 3 (length hashes)
        m0 t = ctx' t [("STYLE","margin:0")]