require "asciidoctor"
require "tempfile"
require "sterile"
require "uuidtools"

module Metanorma
  module Utils
    NAMECHAR = "\u0000-\u0022\u0024\u002c\u002f\u003a-\u0040\\u005b-\u005e"\
      "\u0060\u007b-\u00b6\u00b8-\u00bf\u00d7\u00f7\u037e\u2000-\u200b"\
      "\u200e-\u203e\u2041-\u206f\u2190-\u2bff\u2ff0-\u3000".freeze
    NAMESTARTCHAR = "\\u002d\u002e\u0030-\u0039\u00b7\u0300-\u036f"\
      "\u203f-\u2040".freeze

    class << self
      def to_ncname(tag)
        start = tag[0]
        ret1 = if %r([#{NAMECHAR}#]).match?(start)
                 "_"
               else
                 (%r([#{NAMESTARTCHAR}#]).match?(start) ? "_#{start}" : start)
               end
        ret2 = tag[1..-1] || ""
        (ret1 || "") + ret2.gsub(%r([#{NAMECHAR}#]), "_")
      end

      def anchor_or_uuid(node = nil)
        uuid = UUIDTools::UUID.random_create
        node.nil? || node.id.nil? || node.id.empty? ? "_#{uuid}" : node.id
      end

      def asciidoc_sub(text, flavour = :standoc)
        return nil if text.nil?
        return "" if text.empty?

        d = Asciidoctor::Document.new(
          text.lines.entries,
          { header_footer: false, backend: flavour }
        )
        b = d.parse.blocks.first
        b.apply_subs(b.source)
      end

      def localdir(node)
        docfile = node.attr("docfile")
        docfile.nil? ? "./" : "#{Pathname.new(docfile).parent}/"
      end

      # TODO needs internationalisation
      def smartformat(text)
        text.gsub(/ --? /, "&#8201;&#8212;&#8201;")
          .gsub(/--/, "&#8212;").smart_format.gsub(/</, "&lt;")
          .gsub(/>/, "&gt;")
      end

      def endash_date(elem)
        elem.traverse do |n|
          next unless n.text?

          n.replace(n.text.gsub(/\s+--?\s+/, "&#8211;").gsub(/--/, "&#8211;"))
        end
      end

      # Set hash value using keys path
      # mod from https://stackoverflow.com/a/42425884
      def set_nested_value(hash, keys, new_val)
        key = keys[0]
        if keys.length == 1
          hash[key] = if hash[key].is_a?(Array)
                        (hash[key] << new_val)
                      else
                        hash[key].nil? ? new_val : [hash[key], new_val]
                      end
        elsif hash[key].is_a?(Array)
          hash[key][-1] = {} if !hash[key].empty? && hash[key][-1].nil?
          hash[key] << {} if hash[key].empty? || !hash[key][-1].is_a?(Hash)
          set_nested_value(hash[key][-1], keys[1..-1], new_val)
        elsif hash[key].nil? || hash[key].empty?
          hash[key] = {}
          set_nested_value(hash[key], keys[1..-1], new_val)
        elsif hash[key].is_a?(Hash) && !hash[key][keys[1]]
          set_nested_value(hash[key], keys[1..-1], new_val)
        elsif !hash[key][keys[1]]
          hash[key] = [hash[key], {}]
          set_nested_value(hash[key][-1], keys[1..-1], new_val)
        else
          set_nested_value(hash[key], keys[1..-1], new_val)
        end
        hash
      end

      # not currently used
      def flatten_rawtext_lines(node, result)
        node.lines.each do |x|
          result << if node.respond_to?(:context) &&
              (node.context == :literal || node.context == :listing)
                      x.gsub(/</, "&lt;").gsub(/>/, "&gt;")
                    else
                      # strip not only HTML <tag>, and Asciidoc xrefs <<xref>>
                      x.gsub(/<[^>]*>+/, "")
                    end
        end
        result
      end

      # not currently used
      # if node contains blocks, flatten them into a single line;
      # and extract only raw text
      def flatten_rawtext(node)
        result = []
        if node.respond_to?(:blocks) && node.blocks?
          node.blocks.each { |b| result << flatten_rawtext(b) }
        elsif node.respond_to?(:lines)
          result = flatten_rawtext_lines(node, result)
        elsif node.respond_to?(:text)
          result << node.text.gsub(/<[^>]*>+/, "")
        else
          result << node.content.gsub(/<[^>]*>+/, "")
        end
        result.reject(&:empty?)
      end
    end
  end
end