class Middleman::CoreExtensions::FrontMatter

def before_configuration
  app.files.on_change(:source, &method(:clear_data))
end

def clear_data(updated_files, removed_files)
  (updated_files + removed_files).each do |file|
    @cache.delete(file[:full_path].to_s)
  end
end

def data(path)
  file = app.files.find(:source, path)
  return [{}, nil] unless file
  file_path = file[:full_path].to_s
  @cache[file_path] ||= begin
    if ::Middleman::Util.contains_frontmatter?(file_path, app.config[:frontmatter_delims])
      ::Middleman::Util::Data.parse(
        file,
        app.config[:frontmatter_delims]
      )
    else
      [{}, nil]
    end
  end
end

def initialize(app, options_hash = ::Middleman::EMPTY_HASH, &block)
  super
  @cache = {}
end

def manipulate_resource_list_container!(resource_list)
  resource_list.by_binary(false).each do |resource|
    next if resource.file_descriptor.nil?
    next if resource.file_descriptor[:types].include?(:no_frontmatter)
    fmdata = data(resource.file_descriptor[:full_path].to_s).first.dup
    # Copy over special options
    # TODO: Should we make people put these under "options" instead of having
    # special known keys?
    opts = fmdata.extract!(:layout, :layout_engine, :renderer_options, :directory_index, :content_type)
    opts[:renderer_options].symbolize_keys! if opts.key?(:renderer_options)
    ignored = fmdata.delete(:ignored)
    # TODO: Enhance data? NOOOO
    # TODO: stringify-keys? immutable/freeze?
    resource.add_metadata_options opts
    if fmdata.key?(:id)
      resource_list.update!(resource, :page_id) do
        resource.add_metadata_page fmdata
      end
    else
      resource.add_metadata_page fmdata
    end
    next unless ignored == true && !resource.is_a?(::Middleman::Sitemap::ProxyResource)
    resource_list.update!(resource, :ignored) do
      resource.ignore!
    end
    # TODO: Save new template here somewhere?
  end
end

def template_data_for_file(path)
  data(path).last
end