module Scrivito

  # @api public
  module DefaultCmsRoutingHelper
    # Returns the path for +target+ using the +CmsController+ routes.
    # +target+ can be an +Obj+ or a +Link+ or a +LinkList+.
    # If +target+ is a +Linklist+, it must be non-empty. The first +Link+ from the +LinkList+ will be used.
    # +options+ are optional and include url settings such as path parameters or protocol.
    # @return [String]
    # @api public
    def cms_path(target, options = {})
      cms_path_or_url(target, "path", options)
    end

    # Returns the absolute URL for target using the +CmsController+ routes.
    # +target+ can be an +Obj+ or a +Link+ or a +LinkList+.
    # If +target+ is a +Linklist+, it must be non-empty. The first +Link+ from the +LinkList+ will be used.
    # +options+ are optional and include url settings such as path parameters or protocol.
    # @return [String]
    # @api public
    def cms_url(target, options = {})
      cms_path_or_url(target, "url", options)
    end

    LINK_TO_EMPTY_LINKLIST = "#__empty_linklist"
    LINK_TO_EMPTY_BLOB = "#__empty_blob"

    def cms_path_or_url(target, path_or_url, options)
      if cms_with_editing_context?(target)
        cms_path_or_url_with_editing_context(target, path_or_url, options)
      else
        cms_path_or_url_without_editing_context(target, path_or_url, options)
      end
    end

    def cms_path_or_url_with_editing_context(target, path_or_url, options)
      cms_path_or_url_without_editing_context(target, path_or_url,
          options.merge(cms_editing_context.to_params))
    end

    def cms_path_or_url_without_editing_context(target, path_or_url, options)
      if target.is_a?(Link)
        cms_path_or_url_for_links(target, path_or_url, options)
      elsif target.is_a?(Obj)
        cms_path_or_url_for_objs(target, path_or_url, options)
      elsif target.respond_to?(:first)
        if target.first.is_a?(Link)
          cms_path_or_url_for_links(target.first, path_or_url, options)
        else
          return LINK_TO_EMPTY_LINKLIST
        end
      else
        raise "cms_path or cms_url was called with an instance of #{target.class}. "+
          "It must only be called with an Obj or a Link or a non-empty LinkList."
      end
    end

    def cms_path_or_url_for_links(link, path_or_url, options = {})
      url = basic_url_or_path_for_link(link, path_or_url,
          Rack::Utils.parse_nested_query(link.query).merge(options))
      url = url + "##{link.fragment}" if link.fragment.present?
      url
    end

    def cms_path_or_url_for_objs(obj, path_or_url, options = {})
      permalink = obj.permalink
      if permalink
        __send__("cms_permalink_#{path_or_url}", options.merge(:permalink => permalink))
      elsif obj.homepage?
        __send__("cms_root_#{path_or_url}", options)
      else
        if obj.binary? && cms_editing_context.display_mode != "editing"
          if obj.body_data_url
            enforce_protocol_from_request(obj.body_data_url)
          else
            LINK_TO_EMPTY_BLOB
          end
        else
          __send__(
            "cms_id_#{path_or_url}",
            options.merge(
              id: obj.id,
              slug: obj.slug.presence
            )
          )
        end
      end
    end

    def cms_editing_context
      request.env[EditingContextMiddleware::ENVKEY] || EditingContext.new
    end

    def inplace_editing_allowed?
      cms_editing_context.authenticated_editor?
    end

    private

    def cms_with_editing_context?(target)
      inplace_editing_allowed? && (!target.is_a?(Link) || target.internal?)
    end

    def basic_url_or_path_for_link(link, path_or_url, options = {})
      if link.internal?
        cms_path_or_url_without_editing_context(link.obj, path_or_url, options)
      else
        url = link.url
        url = merge_options(url, options) if options.any?
        url
      end
    end

    def merge_options(url, options)
      parsed_url = URI.parse(url)

      query = Rack::Utils.parse_query(parsed_url.query)
      merged_query = query.merge(options.stringify_keys)
      parsed_url.query = merged_query.to_query

      parsed_url.to_s
    end

    def enforce_protocol_from_request(url)
      request.ssl? && !url.starts_with?('https') ? url.gsub(/^http/, 'https') : url
    end
  end
end