require 'rack/builder'
require 'rack/static'
require 'tilt'
require 'middleman-core/meta_pages/sitemap_tree'
require 'middleman-core/meta_pages/config_setting'

module Middleman
  module MetaPages
    # Metadata pages to be served in preview, in order to present information about the Middleman
    # application and its configuration. Analogous to Firefox/Chrome's "about:" pages.
    #
    # Built using a ghetto little Rack web framework cobbled together because I didn't want to depend
    # on Sinatra or figure out how to host Middleman inside Middleman.
    class Application
      def initialize(middleman)
        # Hold a reference to the middleman application
        @middleman = middleman

        meta_pages = self
        @rack_app = ::Rack::Builder.new do
          # Serve assets from metadata/assets
          use ::Rack::Static, urls: ['/assets'], root: File.join(File.dirname(__FILE__), 'meta_pages')

          map '/' do
            run meta_pages.method(:index)
          end

          map '/sitemap' do
            run meta_pages.method(:sitemap)
          end

          map '/config' do
            run meta_pages.method(:config)
          end
        end
      end

      def call(*args)
        @rack_app.call(*args)
      end

      # The index page
      def index(_)
        template('index.html.erb')
      end

      # Inspect the sitemap
      def sitemap(_)
        resources = @middleman.sitemap.resources(true)

        sitemap_tree = SitemapTree.new

        resources.each do |resource|
          sitemap_tree.add_resource resource
        end

        template('sitemap.html.erb', sitemap_tree: sitemap_tree)
      end

      # Inspect configuration
      def config(_)
        global_config = @middleman.config.all_settings.map { |c| ConfigSetting.new(c) }
        extension_config = {}
        auto_activated_config = {}

        @middleman.extensions.each do |ext_name, extension|
          if ::Middleman::Extensions.auto_activated.include? ext_name
            auto_activated_config[ext_name] = extension_options(extension)
            next
          end

          if extension.is_a?(Hash)
            # Multiple instance extension
            if extension.size == 1
              extension_config[ext_name] = extension_options(extension.values.first)
            else
              extension.each do |inst, ext|
                extension_config["#{ext_name} (#{inst})"] = extension_options(ext)
              end
            end
          else
            extension_config[ext_name] = extension_options(extension)
          end
        end

        template('config.html.erb',
                 global_config: global_config,
                 extension_config: extension_config,
                 auto_activated_config: auto_activated_config,
                 registered_extensions: Middleman::Extensions.registered.dup)
      end

      private

      # Render a template with the given name and locals
      def template(template_name, locals={})
        template_path = File.join(File.dirname(__FILE__), 'meta_pages', 'templates', template_name)
        content = Tilt.new(template_path).render(::Object.new, locals)
        response(content)
      end

      # Respond to an HTML request
      def response(content)
        [200, { 'Content-Type' => 'text/html' }, Array(content)]
      end

      def extension_options(extension)
        extension.options.all_settings.map { |c| ConfigSetting.new(c) }
      end
    end
  end
end