#! /usr/bin/env nix-shell
#! nix-shell -p "haskellPackages.ghcWithPackages (p: [p.mustache p.pandoc p.shake p.deriving-aeson])"
#! nix-shell -i runhaskell

-- pulling heavily from https://abhinavsarkar.net/posts/static-site-generator-using-shake/
-- docs:
-- https://hackage.haskell.org/package/pandoc-3.2.1/docs/doc-index-All.html
-- https://hackage.haskell.org/package/mustache-2.4.2/docs/doc-index.html
--
{-# LANGUAGE ApplicativeDo, DataKinds, DeriveGeneric #-}
{-# LANGUAGE DerivingVia, LambdaCase, TypeApplications #-}

module Main where

import Control.Monad (forM, void)
import Data.Aeson.Types (Result (..))
import Data.List (nub, sortOn)
import Data.Text (Text)
import Data.Time (UTCTime, defaultTimeLocale, formatTime, parseTimeM)
import Deriving.Aeson
import Deriving.Aeson.Stock (PrefixedSnake)
import Development.Shake (Action, Rules, (%>), (|%>), (~>))
import Development.Shake.FilePath ((<.>), (</>))
import Text.Pandoc (Block (Plain), Meta (..), MetaValue (..), Pandoc (..))
import qualified Data.Aeson.Types as A
import qualified Data.HashMap.Strict as HM
import qualified Data.Ord as Ord
import qualified Data.Text as T
import qualified Development.Shake as Shake
import qualified Development.Shake.FilePath as Shake
import qualified Text.Mustache as Mus
import qualified Text.Mustache.Compile as Mus
import qualified Text.Pandoc as Pandoc

main :: IO ()
main = Shake.shakeArgs Shake.shakeOptions $ do
  Shake.withTargetDocs "Build the site" $
    "build" ~> buildTargets
  Shake.withTargetDocs "Clean the built site" $
    "clean" ~> Shake.removeFilesAfter outputDir ["//*"]

outputDir :: String
outputDir = "publish"

buildTargets :: Action ()
buildTargets = do
    assetPaths <- Shake.getDirectoryFiles "" assetGlobs

typstToHtml :: FilePath -> Action Text
typstToHtml filePath = do
  content <- Shake.readFile' filePath
  Shake.quietly . Shake.traced "Typst to HTML" $ do
    doc <- runPandoc . Pandoc.readTypst readerOptions . T.pack $ content
    
    runPandoc . Pandoc.writeHtml5String writerOptions $ doc
  where
    readerOptions =
      Pandoc.def {Pandoc.readerExtensions = Pandoc.pandocExtensions}
    writerOptions =
      Pandoc.def {Pandoc.writerExtensions = Pandoc.pandocExtensions}

assetGlobs :: [String]
assetGlobs = ["css/*.css", "images/*.png"]

runPandoc action =
      Pandoc.runIO (Pandoc.setVerbosity Pandoc.ERROR >> action)
        >>= either (fail . show) return