forked from fedi/mastodon
70 lines
1.5 KiB
Ruby
70 lines
1.5 KiB
Ruby
# frozen_string_literal: true
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class TOCGenerator
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TARGET_ELEMENTS = %w(h1 h2 h3 h4 h5 h6).freeze
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LISTED_ELEMENTS = %w(h2 h3).freeze
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class Section
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attr_accessor :depth, :title, :children, :anchor
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def initialize(depth, title, anchor)
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@depth = depth
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@title = title
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@children = []
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@anchor = anchor
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end
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delegate :<<, to: :children
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end
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def initialize(source_html)
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@source_html = source_html
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@processed = false
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@target_html = ''
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@headers = []
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@slugs = Hash.new { |h, k| h[k] = 0 }
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end
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def html
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parse_and_transform unless @processed
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@target_html
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end
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def toc
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parse_and_transform unless @processed
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@headers
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end
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private
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def parse_and_transform
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return if @source_html.blank?
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parsed_html = Nokogiri::HTML.fragment(@source_html)
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parsed_html.traverse do |node|
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next unless TARGET_ELEMENTS.include?(node.name)
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anchor = node['id'] || node.text.parameterize
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@slugs[anchor] += 1
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anchor = "#{anchor}-#{@slugs[anchor]}" if @slugs[anchor] > 1
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node['id'] = anchor
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next unless LISTED_ELEMENTS.include?(node.name)
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depth = node.name[1..-1]
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latest_section = @headers.last
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if latest_section.nil? || latest_section.depth >= depth
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@headers << Section.new(depth, node.text, anchor)
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else
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latest_section << Section.new(depth, node.text, anchor)
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end
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end
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@target_html = parsed_html.to_s
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@processed = true
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end
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end
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