require "htmlentities"
require "uri" if /^2\./.match?(RUBY_VERSION)
require_relative "./blocks_notes"

module Metanorma
  module Standoc
    module Blocks
      def id_attr(node = nil)
        { id: Metanorma::Utils::anchor_or_uuid(node),
          tag: node&.attr("tag"),
          "multilingual-rendering": node&.attr("multilingual-rendering") }
      end

      def id_unnum_attrs(node)
        attr_code(id_attr(node).merge(
                    unnumbered: node.option?("unnumbered") ? "true" : nil,
                    number: node.attr("number"),
                    subsequence: node.attr("subsequence"),
                  ))
      end

      def formula_attrs(node)
        attr_code(id_unnum_attrs(node)
          .merge(keep_attrs(node).merge(
                   inequality: node.option?("inequality") ? "true" : nil,
                 )))
      end

      def keep_attrs(node)
        { "keep-with-next": node.attr("keep-with-next"),
          "keep-lines-together": node.attr("keep-lines-together") }
      end

      # We append each contained block to its parent
      def open(node)
        role = node.role || node.attr("style")
        reqt_subpart(role) and return requirement_subpart(node)
        role == "form" and return form(node)
        role == "definition" and return termdefinition(node)
        result = []
        node.blocks.each do |b|
          result << send(b.context, b)
        end
        result
      end

      def form(node)
        noko do |xml|
          xml.form **attr_code(id_attr(node)
            .merge(class: node.attr("class"),
                   name: node.attr("name"), action: node.attr("action"))) do |f|
            f << node.content
          end
        end
      end

      def literal_attrs(node)
        attr_code(id_attr(node).merge(keep_attrs(node)))
      end

      def literal(node)
        noko do |xml|
          xml.figure **literal_attrs(node) do |f|
            figure_title(node, f)
            f.pre node.lines.join("\n"),
                  **attr_code(id: Metanorma::Utils::anchor_or_uuid,
                              alt: node.attr("alt"))
          end
        end
      end

      # NOTE: html escaping is performed by Nokogiri
      def stem(node)
        noko do |xml|
          xml.formula **formula_attrs(node) do |s|
            stem_parse(node.lines.join("\n"), s, node.style.to_sym)
          end
        end
      end

      def term_example(node)
        noko do |xml|
          xml.termexample **attr_code(id_attr(node)) do |ex|
            wrap_in_para(node, ex)
          end
        end.join("\n")
      end

      def example(node)
        return term_example(node) if in_terms?

        role = node.role || node.attr("style")
        %w(recommendation requirement permission).include?(role) and
          return requirement(node, role)
        return pseudocode_example(node) if role == "pseudocode"
        return svgmap_example(node) if role == "svgmap"
        return form(node) if role == "form"
        return termdefinition(node) if role == "definition"
        return figure_example(node) if role == "figure"

        reqt_subpart(role) and return requirement_subpart(node)
        example_proper(node)
      end

      def svgmap_attrs(node)
        attr_code(id_attr(node)
          .merge(id: node.id,
                 unnumbered: node.option?("unnumbered") ? "true" : nil,
                 number: node.attr("number"),
                 subsequence: node.attr("subsequence"))
        .merge(keep_attrs(node)))
      end

      def svgmap_example(node)
        noko do |xml|
          xml.svgmap **attr_code(svgmap_attrs(node).merge(
                                   src: node.attr("src"), alt: node.attr("alt"),
                                 )) do |ex|
            figure_title(node, ex)
            ex << node.content
          end
        end.join("\n")
      end

      # prevent A's and other subs inappropriate for pseudocode
      def pseudocode_example(node)
        node.blocks.each { |b| b.remove_sub(:replacements) }
        noko do |xml|
          xml.figure **example_attrs(node).merge(class: "pseudocode") do |ex|
            figure_title(node, ex)
            wrap_in_para(node, ex)
          end
        end.join("\n")
      end

      def example_attrs(node)
        attr_code(id_unnum_attrs(node).merge(keep_attrs(node)))
      end

      def example_proper(node)
        noko do |xml|
          xml.example **example_attrs(node) do |ex|
            node.title.nil? or ex.name { |name| name << node.title }
            wrap_in_para(node, ex)
          end
        end.join("\n")
      end

      def figure_example(node)
        noko do |xml|
          xml.figure **figure_attrs(node) do |ex|
            node.title.nil? or ex.name { |name| name << node.title }
            wrap_in_para(node, ex)
          end
        end.join("\n")
      end

      def figure_title(node, out)
        return if node.title.nil?

        out.name { |name| name << node.title }
      end

      def figure_attrs(node)
        attr_code(id_unnum_attrs(node).merge(keep_attrs(node)))
      end

      def image(node)
        noko do |xml|
          xml.figure **figure_attrs(node) do |f|
            figure_title(node, f)
            f.image **image_attributes(node)
          end
        end
      end

      def para_attrs(node)
        attr_code(id_attr(node).merge(keep_attrs(node)
          .merge(align: node.attr("align"),
                 variant_title: node.role == "variant-title" ? true : nil,
                 type: node.attr("type"))))
      end

      def paragraph(node)
        return termsource(node) if node.role == "source"

        noko do |xml|
          xml.p **para_attrs(node) do |xml_t|
            xml_t << node.content
          end
        end.join("\n")
      end

      def quote_attrs(node)
        attr_code(id_attr(node).merge(keep_attrs(node))
          .merge(align: node.attr("align")))
      end

      def quote_attribution(node, out)
        if node.attr("citetitle")
          m = /^(?<cite>[^,]+)(?:,(?<text>.*$))?$/m.match node.attr("citetitle")
          out.source **attr_code(target: m[:cite], type: "inline") do |s|
            s <<  m[:text]
          end
        end
        node.attr("attribution") and
          out.author { |a| a << node.attr("attribution") }
      end

      def quote(node)
        noko do |xml|
          xml.quote **quote_attrs(node) do |q|
            quote_attribution(node, q)
            wrap_in_para(node, q)
          end
        end.join("\n")
      end

      def listing_attrs(node)
        attr_code(id_attr(node).merge(keep_attrs(node)
                  .merge(lang: node.attr("language"),
                         unnumbered: node.option?("unnumbered") ? "true" : nil,
                         number: node.attr("number"),
                         filename: node.attr("filename"))))
      end

      # NOTE: html escaping is performed by Nokogiri
      def listing(node)
        fragment = ::Nokogiri::XML::Builder.new do |xml|
          xml.sourcecode **listing_attrs(node) do |s|
            figure_title(node, s)
            s << node.content
          end
        end
        fragment.to_xml(encoding: "US-ASCII", save_with:
                        Nokogiri::XML::Node::SaveOptions::NO_DECLARATION)
      end

      def pass(node)
        noko do |xml|
          xml.passthrough **attr_code(formats:
                                      node.attr("format") || "metanorma") do |p|
            p << HTMLEntities.new.encode(node.content, :basic, :hexadecimal)
          end
        end
      end
    end
  end
end