module Middleman::Renderers::AsciiDoc

def registered(app)
  app.config.define_setting :asciidoc, {
    safe: :safe,
    backend: :html5,
    attributes: %W(showtitle env=middleman env-middleman middleman-version=#{::Middleman::VERSION})
  }, 'AsciiDoc engine options (Hash)'
  app.config.define_setting :asciidoc_attributes, [], 'AsciiDoc custom attributes (Array)'
  app.before_configuration do
    template_extensions adoc: :html
  end
  app.after_configuration do
    # QUESTION should base_dir be equal to docdir instead?
    config[:asciidoc][:base_dir] = source_dir
    config[:asciidoc][:attributes].concat(config[:asciidoc_attributes] || [])
    config[:asciidoc][:attributes] << %(imagesdir=#{File.join((config[:http_prefix] || '/').chomp('/'), config[:images_dir])})
    sitemap.provides_metadata(/\.adoc$/) do |path|
      # read the AsciiDoc header only to set page options and data
      # header values can be accessed via app.data.page.<name> in the layout
      doc = Asciidoctor.load_file path, safe: :safe, parse_header_only: true
      opts = {}
      if doc.attr? 'page-layout'
        case (layout = (doc.attr 'page-layout'))
        when '', 'false'
          opts[:layout] = false
        else
          opts[:layout] = layout
        end
      end
      opts[:layout_engine] = (doc.attr 'page-layout-engine') if doc.attr? 'page-layout-engine'
      # TODO: override attributes to set docfile, docdir, docname, etc
      # alternative is to set :renderer_options, which get merged into options by the rendering extension
      # opts[:attributes] = config[:asciidoc][:attributes].dup
      # opts[:attributes].concat %W(docfile=#{path} docdir=#{File.dirname path} docname=#{(File.basename path).sub(/\.adoc$/, '')})
      page = {}
      page[:title] = doc.doctitle
      page[:date] = (doc.attr 'date') unless (doc.attr 'date').nil?
      # TODO: grab all the author information
      page[:author] = (doc.attr 'author') unless (doc.attr 'author').nil?
      { options: opts, page: ::Middleman::Util.recursively_enhance(page) }
    end
  end
end