A Gollum Wiki macro for better Global Table of Contents

nested_toc_macro.rb

module Gollum

  # monkey patching Gollum::Page is a questionable decision. Could be refactored as a container or super class
  class Page
    attr_accessor :children

    def pretty_title
      # is this the right way to get th wiki_options from here?
      @pt ||= if Precious::App.settings.wiki_options[:h1_title]
            find_header_node(text_data)
          end || self.url_path_display
    end

    private

    # this is one of the jankiest parts of this code. 
    # The problem is that I can't use .formatted_data 
    # because that tries to render the whole page 
    # including this macro, which causes a stack overflow.
    # So I just use the raw text_data. But that means the 
    # usual way of parsing the doc with nokogiri and 
    # selecting the first h1 can't work.
    # Instead I just hacked it to "work" in my limited
    # (but common) use case of having markdown with "#" 
    # being the title character.
    # Ideally we might parse the document with macros 
    # stripped out to get the title, but maybe the 
    #performance hit of doing that now is too much?
    def find_header_node(markdown)
      #only handles markdown
      markdown.split("\n").
          select{|line| line =~ /^#[A-Za-z0-9\s]/ }.
          first.
          gsub('#','').strip
    end

  end

  class Macro
    class NestedTOC < Gollum::Macro

      class TOCPage
        attr_accessor :url, :title, :pages
        def initialize(url, title, pages)
          self.url = url
          self.title = title
          self.pages = convert_pages(pages)
        end

        def to_s
          format('<li><a href="%s">%s</a>%s</li>',
                 self.url,
                 self.title,
                 pages_to_s
          )
        end

        private

        def convert_pages(pages)
          Array(pages).map do |p|
            p.is_a?(TOCPage) ? p : TOCPage.new(p.url_path, p.pretty_title, p.children)
          end
        end

        def pages_to_s
          if self.pages.size > 0
            format('<ul>%s</ul>', self.pages.map(&:to_s).join)
          end
        end

      end

      def render(title = 'Site Table of Contents')
        if @wiki.pages.size > 0
          result = '<ul>' + nested_toc_pages.map(&:to_s).join + '</ul>'
        end
        "<div class='toc'><div class='toc-title'>#{title}</div>#{result}</div>"
      end

      private

      # this is probably expensive when you get thousands of pages
      def pages_with_children
        pages_remaining = @wiki.pages.dup
        top_level_pages = pages_remaining.reject {|p| p.url_path.include?('/') }
        process_level(top_level_pages, pages_remaining - top_level_pages)
      end

      def process_level(pages, pages_remaining)
        pages.map do |tlp|
          tlp.children = select_child_pages(pages_remaining, tlp.url_path)
          process_level(tlp.children, pages_remaining - tlp.children)
          tlp
        end
      end

      def select_child_pages(pages, parent_path)
        pages.select do |p|
          parent_path = "#{parent_path}/" unless parent_path.end_with?('/')
          #this page's url path starts with the parent we're looking for, and...
          p.url_path.start_with?(parent_path) &&
              # also isn't part of a deeper nesting
              !p.url_path[parent_path.length..-1].include?('/')
        end
      end

      def nested_toc_pages
        @nested ||= pages_with_children.map do |p|
          TOCPage.new(p.url_path, p.pretty_title, p.children)
        end
      end

    end
  end
end