module IsoDoc::HtmlFunction
  module Footnotes

    def footnotes(div)
      return if @footnotes.empty?

      @footnotes.each { |fn| div.parent << fn }
    end

    def make_table_footnote_link(out, fnid, fnref)
      attrs = { href: "##{fnid}", class: "TableFootnoteRef" }
      out.a **attrs do |a|
        a << fnref
      end
    end

    def make_table_footnote_target(out, fnid, fnref)
      attrs = { id: fnid, class: "TableFootnoteRef" }
      out.span do |s|
        out.span **attrs do |a|
          a << fnref
        end
        insert_tab(s, 1)
      end
    end

    def make_table_footnote_text(node, fnid, fnref)
      attrs = { id: "fn:#{fnid}" }
      noko do |xml|
        xml.div **attr_code(attrs) do |div|
          make_table_footnote_target(div, fnid, fnref)
          node.children.each { |n| parse(n, div) }
        end
      end.join("\n")
    end

    def make_generic_footnote_text(node, fnid)
      noko do |xml|
        xml.aside **{ id: "fn:#{fnid}", class: "footnote" } do |div|
          node.children.each { |n| parse(n, div) }
        end
      end.join("\n")
    end

    def get_table_ancestor_id(node)
      table = node.ancestors("table") || node.ancestors("figure")
      return UUIDTools::UUID.random_create.to_s if table.empty?

      table.last["id"]
    end

    # @seen_footnote:
    # do not output footnote text if we have already seen it for this table

    def table_footnote_parse(node, out)
      fn = node["reference"] || UUIDTools::UUID.random_create.to_s
      tid = get_table_ancestor_id(node)
      make_table_footnote_link(out, tid + fn, fn)
      return if @seen_footnote.include?(tid + fn)

      @in_footnote = true
      out.aside **{ class: "footnote" } do |a|
        a << make_table_footnote_text(node, tid + fn, fn)
      end
      @in_footnote = false
      @seen_footnote << (tid + fn)
    end

    def footnote_parse(node, out)
      return table_footnote_parse(node, out) if (@in_table || @in_figure) &&
        !node.ancestors.map(&:name).include?("name")

      fn = node["reference"] || UUIDTools::UUID.random_create.to_s
      attrs = { class: "FootnoteRef", href: "#fn:#{fn}" }
      out.a **attrs do |a|
        a.sup { |sup| sup << fn }
      end
      make_footnote(node, fn)
    end

    def make_footnote(node, fnote)
      return if @seen_footnote.include?(fnote)

      @in_footnote = true
      @footnotes << make_generic_footnote_text(node, fnote)
      @in_footnote = false
      @seen_footnote << fnote
    end
  end
end