module Scrivito

class ChildListTag < Struct.new(:tag_name, :obj, :field_name, :view)
  include TagRenderer

  def initialize(tag_name, obj, field_name, view)
    unless field_name == 'toclist'
      raise "#{field_name} is not (yet) supported. Currently only toclist is supported."
    end
    super
  end

  def options
    return {} unless user_present? || obj.path.nil?

    allowed_classes = if classes = Obj.valid_page_classes_beneath(obj.path)
                        classes.map(&:to_s)
                      end

    options = {
      'private-child-list-allowed-classes' => allowed_classes.to_json,
      'private-child-list-path'            => obj.path,
      'private-obj-description-for-editor' => obj.description_for_editor,
    }

    if obj.sortable_toclist?
      options['private-child-list-order-obj-id'] = obj.id
      modification = comparison.modification_for_attribute(obj, :child_order)
      if modification == Modification::EDITED
        options['private-child-list-modification'] = modification
      end
    end

    options
  end

  def content(&block)
    return unless block_given?

    is_sortable = obj.sortable_toclist? && user_present?
    rendered_children = obj.sorted_toclist.map do |child|
      obj_tag = ObjTag.new(child, is_sortable, comparison.modification(child), view)
      yield obj_tag, child
      obj_tag.rendered
    end
    view.safe_join(rendered_children)
  end

  #
  # This is a helper class for {ScrivitoHelper#scrivito_tag_list}.
  #
  # @api public
  #
  class ObjTag < Struct.new(:obj, :is_sortable, :modification, :view)
    include TagRenderer

    attr_reader :tag_name, :rendered

    #
    # Renders HTML for the corresponding child with in-place editing enabled.
    #
    # @api public
    #
    # @note This method can be called only _once_ per child.
    #
    # @param tag_name [String, Symbol] Name of the HTML tag (e.g. +:li+ or +:div+).
    # @param html_options [Hash] Options to be passed to +content_tag+. Use them to add HTML
    #   attributes to the tag.
    #
    # @return [String] The rendered HTML tag.
    #
    # @see ScrivitoHelper#scrivito_tag_list
    #
    # @example Render a +div+ element containing text, and assign to it the +my_list_element+ CSS class.
    #   list.tag(:div, class: "my_list_element") do
    #     "random content"
    #   end
    #
    def tag(tag_name, html_options = {}, &block)
      raise '"list.tag" can only be called once per iteration!' if @rendered
      @tag_name = tag_name
      @rendered = render(html_options, &block)
      nil
    end

    def options
      return {} unless is_sortable
      options = {
        'private-obj-id'                     => obj.id,
        'private-obj-description-for-editor' => obj.description_for_editor,
      }
      if modification == Modification::NEW || modification == Modification::DELETED
        options['private-obj-modification'] = modification
      end
      options
    end

    def content(&block)
      view.capture { yield } if block_given?
    end
  end

  private

  def user_present?
    view.scrivito_user.present?
  end

  def comparison
    EditingContextMiddleware.from_request(view.request).comparison
  end
end

end