import Development.Shake
import Development.Shake.Command
import Development.Shake.FilePath
import Development.Shake.Util

main :: IO ()
main = do
  let shOpts = shakeOptions { shakeVerbosity = Chatty, shakeLintInside = ["\\"] }
  shakeArgsForward shOpts buildRules

buildRules :: Action ()
buildRules = do
  allPosts <- buildPosts
  buildIndex allPosts
  buildFeed allPosts
  copyStaticFiles

-- | Find and build all posts
buildPosts :: Action [Post]
buildPosts = do
  pPaths <- getDirectoryFiles "." ["site/posts//*.md"]
  forP pPaths buildPost

-- | Load a post, process metadata, write it to output, then return the post object
-- Detects changes to either post content or template
buildPost :: FilePath -> Action Post
buildPost srcPath = cacheAction ("build" :: T.Text, srcPath) $ do
  liftIO . putStrLn $ "Rebuilding post: " <> srcPath
  postContent <- readFile' srcPath
  -- load post content and metadata as JSON blob
  postData <- markdownToHTML . T.pack $ postContent
  let postUrl = T.pack . dropDirectory1 $ srcPath -<.> "html"
      withPostUrl = _Object . at "url" ?~ String postUrl
  -- Add additional metadata we've been able to compute
  let fullPostData = withSiteMeta . withPostUrl $ postData
  template <- compileTemplate' "site/templates/post.html"
  writeFile' (outputFolder </> T.unpack postUrl) . T.unpack $ substitute template fullPostData
  convert fullPostData