aboutsummaryrefslogtreecommitdiffstats
path: root/guides/rails_guides/markdown.rb
blob: bf2cc82c7c7d69117b0926133b3631adca109ebc (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
require "redcarpet"
require "nokogiri"
require "rails_guides/markdown/renderer"

module RailsGuides
  class Markdown
    def initialize(view:, layout:, edge:, version:)
      @view          = view
      @layout        = layout
      @edge          = edge
      @version       = version
      @index_counter = Hash.new(0)
      @raw_header    = ""
      @node_ids      = {}
    end

    def render(body)
      @raw_body = body
      extract_raw_header_and_body
      generate_header
      generate_title
      generate_body
      generate_structure
      generate_index
      render_page
    end

    private

      def dom_id(nodes)
        dom_id = dom_id_text(nodes.last.text)

        # Fix duplicate node by prefix with its parent node
        if @node_ids[dom_id]
          if @node_ids[dom_id].size > 1
            duplicate_nodes = @node_ids.delete(dom_id)
            new_node_id = "#{duplicate_nodes[-2][:id]}-#{duplicate_nodes.last[:id]}"
            duplicate_nodes.last[:id] = new_node_id
            @node_ids[new_node_id] = duplicate_nodes
          end

          dom_id = "#{nodes[-2][:id]}-#{dom_id}"
        end

        @node_ids[dom_id] = nodes
        dom_id
      end

      def dom_id_text(text)
        escaped_chars = Regexp.escape('\\/`*_{}[]()#+-.!:,;|&<>^~=\'"')

        text.downcase.gsub(/\?/, "-questionmark")
                     .gsub(/!/, "-bang")
                     .gsub(/[#{escaped_chars}]+/, " ").strip
                     .gsub(/\s+/, "-")
      end

      def engine
        @engine ||= Redcarpet::Markdown.new(Renderer,
          no_intra_emphasis: true,
          fenced_code_blocks: true,
          autolink: true,
          strikethrough: true,
          superscript: true,
          tables: true
        )
      end

      def extract_raw_header_and_body
        if @raw_body =~ /^\-{40,}$/
          @raw_header, _, @raw_body = @raw_body.partition(/^\-{40,}$/).map(&:strip)
        end
      end

      def generate_body
        @body = engine.render(@raw_body)
      end

      def generate_header
        @header = engine.render(@raw_header).html_safe
      end

      def generate_structure
        @headings_for_index = []
        if @body.present?
          @body = Nokogiri::HTML.fragment(@body).tap do |doc|
            hierarchy = []

            doc.children.each do |node|
              if node.name =~ /^h[3-6]$/
                case node.name
                when "h3"
                  hierarchy = [node]
                  @headings_for_index << [1, node, node.inner_html]
                when "h4"
                  hierarchy = hierarchy[0, 1] + [node]
                  @headings_for_index << [2, node, node.inner_html]
                when "h5"
                  hierarchy = hierarchy[0, 2] + [node]
                when "h6"
                  hierarchy = hierarchy[0, 3] + [node]
                end

                node[:id] = dom_id(hierarchy)
                node.inner_html = "#{node_index(hierarchy)} #{node.inner_html}"
              end
            end
          end.to_html
        end
      end

      def generate_index
        if @headings_for_index.present?
          raw_index = ""
          @headings_for_index.each do |level, node, label|
            if level == 1
              raw_index += "1. [#{label}](##{node[:id]})\n"
            elsif level == 2
              raw_index += "    * [#{label}](##{node[:id]})\n"
            end
          end

          @index = Nokogiri::HTML.fragment(engine.render(raw_index)).tap do |doc|
            doc.at("ol")[:class] = "chapters"
          end.to_html

          @index = <<-INDEX.html_safe
          <div id="subCol">
            <h3 class="chapter"><img src="images/chapters_icon.gif" alt="" />Chapters</h3>
            #{@index}
          </div>
          INDEX
        end
      end

      def generate_title
        if heading = Nokogiri::HTML.fragment(@header).at(:h2)
          @title = "#{heading.text} — Ruby on Rails Guides"
        else
          @title = "Ruby on Rails Guides"
        end
      end

      def node_index(hierarchy)
        case hierarchy.size
        when 1
          @index_counter[2] = @index_counter[3] = @index_counter[4] = 0
          "#{@index_counter[1] += 1}"
        when 2
          @index_counter[3] = @index_counter[4] = 0
          "#{@index_counter[1]}.#{@index_counter[2] += 1}"
        when 3
          @index_counter[4] = 0
          "#{@index_counter[1]}.#{@index_counter[2]}.#{@index_counter[3] += 1}"
        when 4
          "#{@index_counter[1]}.#{@index_counter[2]}.#{@index_counter[3]}.#{@index_counter[4] += 1}"
        end
      end

      def render_page
        @view.content_for(:header_section) { @header }
        @view.content_for(:page_title) { @title }
        @view.content_for(:index_section) { @index }
        @view.render(layout: @layout, html: @body.html_safe)
      end
  end
end