module RailsConnector
  # This module contains a helper that can be used to render attributes of the CMS models.
  # @api public
  module DisplayHelper
    # For a consistent look of your site and easy maintenance, only the display helpers
    # should be used to render an attribute <em>value</em> of a CMS model.
    #
    #   <%= display_value @obj.title %>
    # Renders the value, taking its type into account.
    # * An HtmlString will be exported by converting its links
    # * A Time will be exported in an international form: Year-Month-Day Hour:Minutes
    # * A non-HTML String will be quoted
    # * other values will be rendered unchanged
    #
    # @api public
    def display_value(value)
      case value
      when MarkdownString then markdown(convert_links(value)).html_safe
      when HtmlString then convert_links(value).html_safe
      when String then html_escape_once(value).html_safe
      when Time then html_escape_once(l(value)).html_safe
      else value
      end
    end

    def display_original_value(value)
      case value
      when HtmlString then convert_links(value, ignore_body_data_url: true).html_safe
      else display_value(value)
      end
    end

    # Renders a field from the CMS, including an edit marker for the preview
    # If the option :marker is +false+, no edit marker will be rendered.
    #
    # <%= display_field @obj, :title %>
    #
    # When creating an edit marker, all options except :marker are passed to {MarkerHelper#edit_marker}.
    #
    # @api public
    def display_field(obj, attr, options = {})
      options.reverse_merge!({
                               marker: !%i(id path created last_changed version).include?(attr.to_sym)
                             })
      if options.delete :marker
        edit_marker(obj, attr, options) do |obj, attr|
          display_value obj[attr]
        end
      else
        display_value obj[attr]
      end
    end

    # Legacy method - deprecated
    #
    # Use display_value and display_field instead
    def display(*args)
      options = if args.last.is_a? Hash
                  args.pop
                else
                  {}
                end
      return display_value(args.first) if args.size == 1

      display_field(args[0], args[1], options)
    end

    private

    def markdown(string)
      require "maruku"
      Maruku.new(string).to_html
    end

    LINK_PATTERN = '<?\binternallink:(\d+)\b>?'.freeze
    LINK_EXPRESSION = /#{LINK_PATTERN}/.freeze

    def convert_links(content_attribute, cms_path_options = {})
      return content_attribute unless content_attribute =~ LINK_EXPRESSION

      link_map = content_attribute.source.text_links.each_with_object({}) do |link, map|
        map[link.id.to_s] = link
      end
      content_attribute.gsub(/#{LINK_PATTERN}(['"]?)/) do
        link = link_map[Regexp.last_match(1).to_s]
        if link.blank?
          "#{CmsRoutingHelper::LINK_TO_UNREACHABLE}#{Regexp.last_match(2)}"
        else
          uri = "#{cms_path(link, cms_path_options)}#{Regexp.last_match(2)}"
          if link.markdown?
            markdown_link(link, uri)
          else
            html_link(link, uri)
          end
        end
      end
    end

    def html_link(link, uri)
      subst = uri
      name, value =
        case link.tag_name
        when "img", "input"
          ["alt", link.title || ""]
        when "a", "link"
          ["title", begin link.title unless link.title.blank? end]
        end
      subst << %( #{name}="#{html_escape_once(value)}") if value
      subst << %( target="#{html_escape_once(link.target)}") unless link.target.blank?
      subst
    end

    def markdown_link(link, uri)
      subst = "<#{uri}>"
      unless link.title.blank?
        case link.markdown_type
        when "inline", "reference"
          subst << %( "#{html_escape_once(link.title)}")
        end
      end
      subst
    end
  end
end