require "nokogiri"

module Goethe
  class Utils
    class << self

      #
      # 从文本中找到链接，转化为 `<a>` 标签，找到换行符，转换为 `<br>` 标签
      #
      # @param [String] str
      #
      # @return [String]
      #
      def auto_link(str)
        str = str.dup
        str.gsub!(/<(S*?)[^>]*>.*?|<.*? \/>/) do |s|
          s.gsub!(/</, "&lt;")
          s.gsub!(/>/, "&gt;")
        end

        str.gsub!(/((https|http|ftp):\/\/)([a-zA-Z0-9.\-_%&=\/\#:\?]+)/i) do
          protocol, url = $1, $3
          %Q{<a href="#{protocol}#{url}" rel="nofollow" target="_blank">#{protocol}#{url}</a>}
        end

        str.gsub!(/\r\n|\n/, "<br>")
        str
      end

      #
      # 替换文本中所有的 HTML 标签，默认替换成空格
      #
      # @param [String] str
      # @param [String] replacement - 替换的字符，默认是空格
      #
      # @return [String]
      #
      def remove_html_tags(str, replacement: " ")
        return "" if str.nil?
        str.gsub(Goethe::Regex[:HTML_TAGS], replacement)
          .gsub(Goethe::Regex[:ADDITIONAL_HTML_TAG], replacement)
      end

      #
      # 移除文本中所有的 Markdown 控制字符
      #
      # @param [String] str
      #
      # @return [String]
      #
      def remove_markdown_symbols(str)
        return "" if str.nil?

        result = ""

        # HEADERS
        result = str.gsub(Goethe::Regex[:MARKDOWN][:HEADERS], "")
        #p "HEADERS: #{result}, #{result.size}"


        result = result.gsub(Goethe::Regex[:MARKDOWN][:BLOCKQUOTES], "")
        #p "BLOCKQUOTES: #{result}, #{result.size}"


        # RULERS
        result = result.gsub(Goethe::Regex[:MARKDOWN][:HRULERS], "") do
          $2
        end
        #p "RULERS: #{result}, #{result.size}"

        # LISTS
        result = result.gsub(Goethe::Regex[:MARKDOWN][:LISTS], "")
        #p "LISTS: #{result}, #{result.size}"

        # EMPHASIS
        result = result.gsub(Goethe::Regex[:MARKDOWN][:EMPHASIS]) do
          $2
        end


        # IMAGES
        result = result.gsub(Goethe::Regex[:MARKDOWN][:IMAGES], "")


        # LINKs
        result = result.gsub(Goethe::Regex[:MARKDOWN][:LINKS]) do
          $1
        end

        # COPYRIGHT
        result = result.gsub(Goethe::Regex[:MARKDOWN][:COPYRIGHT], "")

        # <quock_link>
        result = result.gsub(Goethe::Regex[:MARKDOWN][:QUICK_LINKS]) do
          " #{$1} "
        end

        result
      end
    end
  end
end