module Handler.Extract where

import Import

import Text.Pandoc
import Text.Pandoc.Walk (walk)
import Text.Pandoc.Shared (stringify)

import Data.Maybe

import System.IO (withFile, IOMode(..))

extractHeaders :: Block -> [String]
extractHeaders (Header 1 _ x) = [stringify x]
extractHeaders _ = []

extractFirstHeader :: Pandoc -> Maybe String
extractFirstHeader doc = case queryWith extractHeaders doc of
  (s:_) -> Just s
  [] -> Nothing

extractParas :: Block -> [String]
extractParas (Para x) = [stringify x]
extractParas _ = []

extractFirstPara :: Pandoc -> Maybe String
extractFirstPara doc = case queryWith extractParas doc of
  (s:_) -> Just s
  [] -> Nothing

readDoc :: String -> Pandoc
readDoc s = case readMarkdown def s of
                Right doc -> doc
                Left err  -> error (show err)

defaultTitle :: String
defaultTitle = "[???]"

defaultDescription :: String
defaultDescription = ""

readmeFile :: FilePath
readmeFile = "README.md"

getTitleAndDescription :: String -> (String, String)
getTitleAndDescription contents = (title, description)
                       where title = fromMaybe defaultTitle $ extractFirstHeader doc
                             description = fromMaybe defaultDescription $ extractFirstPara doc
                             doc = readDoc contents

extractTitleAndDescription :: FilePath -> IO (String, String)
extractTitleAndDescription fp = do
  contents <- readFile fp
  return $ getTitleAndDescription contents