{ pkgs, inputs }: 
{ 
  name,
  version,

  # TODO: do not require flakes
  markdollParser ? inputs.markdoll.packages.${pkgs.system}.markdoll.override({
    danger = true;
  }), 
  markdollPlugins ? [],
  src,

  layoutSrc,
  # otherwise set by frontmatter
  defaultLayout ? "default.html",
}: let 
  markdoll = "${markdollParser}/bin/markdoll";
in pkgs.stdenvNoCC.mkDerivation {
  inherit name version src;

  buildPhase = ''
    export PATH="$PATH:${pkgs.lib.makeBinPath markdollPlugins}"
    mkdir dist

    echoerr() { cat <<< "$@" 1>&2; }

    layout_inject() {
      local layoutFile=$1
      local placeholder=$2
      local contentFile=$3

      local layout=$(cat $layoutFile)
      local content=$(cat $contentFile)
      echo "''${layout/"$placeholder"/"$content"}"
    }

    get_frontmatter() {
      key=$1
      file=$2

      keyLine=$(grep -e "^$key: " $file || echo "")
      sed "s/.*: //" <<<$keyLine | xargs
    }

    render_final() {
      local file=$1
      local outFile=$2
      local content=$3

      ### Frontmatter: Get Layout
      local layout="${defaultLayout}"
      local layoutFm=$(get_frontmatter layout $file)
      if [ ! -z $layoutFm ]; then
        layout="$layoutFm"
      fi
      
      local layoutPath="$layout"
      if [ ! -f $layoutPath ]; then
        layoutPath="${layoutSrc}/$layout"
        if [ ! -f $layoutPath ]; then
          echo "Layout file $layout not found"
          exit 1
        fi
      fi
      
      ### Frontmatter: Title
      local title=$(get_frontmatter title $file)
      if [ -z $title ]; then
        title=$(basename $file | sed -e 's/.doll$//')
      fi

      ### Frontmatter: Meta Head Stuff
      local head=""
      local meta_description=$(get_frontmatter description $file)
      if [ ! -z meta_description ]; then
        head="$head<meta name='description' content='$meta_description'>"
      fi
      local meta_tags=$(get_frontmatter tags $file)
      if [ ! -z meta_tags ]; then
        head="$head<meta name='keywords' content='$meta_tags'>"
      fi
      local meta_author=$(get_frontmatter author $file)
      if [ ! -z meta_author ]; then
        head="$head<meta name='author' content='$meta_author'>"
      fi

      ### Layout: Title + Content
      layout_inject $layoutPath %%TITLE%% <<<"$title" > $outFile.tmp.1
      layout_inject $outFile.tmp.1 %%HEAD%% <<<"$head" > $outFile.tmp.2
      layout_inject $outFile.tmp.2 %%CONTENT%% $content > $outFile.tmp.final
      
      ### Layout: Cleanup Tmpfiles
      cp $outFile.tmp.final $outFile
      rm $outFile.tmp*
    }

    echo ">>> DOLLFILES"
    dollFiles=$(find . -name '*.doll')
    echo $dollFiles
    
    for file in $dollFiles; do
      outFile=$(realpath -m "dist/$(echo $file | sed -e 's/.doll$/.html/')")
      mkdir -p $(dirname $outFile)
      
      echo "reading $file; plopping $outFile"

      ### Markdoll: Convert
      local content=$(cat $file | ${markdoll} convert | tee $outFile.tmp.render)

      render_final $file $outFile $outFile.tmp.render
    done
  '';

  installPhase = ''
    cp -rv dist $out
  '';
}