module IsoDoc::HtmlFunction
  module Comments

    def in_comment
      @in_comment
    end

    def comments(div)
=begin
      return if @comments.empty?
      div.div **{ style: "mso-element:comment-list" } do |div1|
        @comments.each { |fn| div1.parent << fn }
      end
=end
    end

    def review_note_parse(node, out)
=begin
      fn = @comments.length + 1
      make_comment_link(out, fn, node)
      @in_comment = true
      @comments << make_comment_text(node, fn)
      @in_comment = false
=end
    end

    def comment_link_attrs(fnote, node)
      { style: "MsoCommentReference", target: fnote,
        class: "commentLink", from: node["from"],
        to: node["to"] }
    end

    # add in from and to links to move the comment into place
    def make_comment_link(out, fnote, node)
      out.span(**comment_link_attrs(fnote, node)) do |s1|
          s1.a **{ style: "mso-comment-reference:SMC_#{fnote};"\
                   "mso-comment-date:#{node['date'].gsub(/[-:Z]/, '')}" }
        end
    end

    def make_comment_target(out)
      out.span **{ style: "MsoCommentReference" } do |s1|
          s1.span **{ style: "mso-special-character:comment" }
        end
    end

    def make_comment_text(node, fnote)
      noko do |xml|
        xml.div **{ style: "mso-element:comment", id: fnote } do |div|
          div.span **{ style: %{mso-comment-author:"#{node['reviewer']}"} }
          make_comment_target(div)
          node.children.each { |n| parse(n, div) }
        end
      end.join("\n")
    end

    def comment_cleanup(docxml)
=begin
      move_comment_link_to_from(docxml)
      reorder_comments_by_comment_link(docxml)
      embed_comment_in_comment_list(docxml)
=end
    end

    COMMENT_IN_COMMENT_LIST =
      '//div[@style="mso-element:comment-list"]//'\
      'span[@style="MsoCommentReference"]'.freeze

    def embed_comment_in_comment_list(docxml)
      docxml.xpath(COMMENT_IN_COMMENT_LIST).each do |x|
        n = x.next_element
        n&.children&.first&.add_previous_sibling(x.remove)
      end
      docxml
    end

    def move_comment_link_to_from1(x, fromlink)
      x.remove
      link = x.at(".//a")
      fromlink.replace(x)
      link.children = fromlink
    end

    def comment_attributes(docxml, x)
      fromlink = docxml.at("//*[@id='#{x['from']}']")
      return(nil) if fromlink.nil?

      tolink = docxml.at("//*[@id='#{x['to']}']") || fromlink
      target = docxml.at("//*[@id='#{x['target']}']")
      { from: fromlink, to: tolink, target: target }
    end

    def wrap_comment_cont(from, target)
      s = from.replace("<span style='mso-comment-continuation:#{target}'>")
      s.first.children = from
    end

    def skip_comment_wrap(from)
      from["style"] != "mso-special-character:comment"
    end

    def insert_comment_cont(from, upto, target)
      # includes_to = from.at(".//*[@id='#{upto}']")
      while !from.nil? && from["id"] != upto
        following = from.xpath("./following::*")
        (from = following.shift) && incl_to = from.at(".//*[@id='#{upto}']")
        while !incl_to.nil? && !from.nil? && skip_comment_wrap(from)
          (from = following.shift) && incl_to = from.at(".//*[@id='#{upto}']")
        end
        wrap_comment_cont(from, target) if !from.nil?
      end
    end

    def move_comment_link_to_from(docxml)
      docxml.xpath('//span[@style="MsoCommentReference"][@from]').each do |x|
        attrs = comment_attributes(docxml, x) || next
        move_comment_link_to_from1(x, attrs[:from])
        insert_comment_cont(attrs[:from], x["to"], x["target"])
      end
    end

    def get_comments_from_text(docxml, link_order)
      comments = []
      docxml.xpath("//div[@style='mso-element:comment']").each do |c|
        next unless c["id"] && !link_order[c["id"]].nil?

        comments << { text: c.remove.to_s, id: c["id"] }
      end
      comments.sort! { |a, b| link_order[a[:id]] <=> link_order[b[:id]] }
      # comments
    end

    COMMENT_TARGET_XREFS =
      "//span[@style='mso-special-character:comment']/@target".freeze

    def reorder_comments_by_comment_link(docxml)
      link_order = {}
      docxml.xpath(COMMENT_TARGET_XREFS).each_with_index do |target, i|
        link_order[target.value] = i
      end
      comments = get_comments_from_text(docxml, link_order)
      list = docxml.at("//*[@style='mso-element:comment-list']") || return
      list.children = comments.map { |c| c[:text] }.join("\n")
    end
  end
end