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?

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

    if obj.has_attribute?(:child_order)
      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.has_attribute?(:child_order) && user_present?
    rendered_children = sorted_children.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

    #
    # @api public
    #
    # @param tag_name [String, Symbol] Name of the html tag (e.g. +:div+ or +:span+).
    # @param html_options [Hash] Additional options, which are passed to +content_tag+.
    #   Use them to add HTML attributes to the tag.
    #
    # @return [String] The rendered html tag
    #
    # @example Render a <div> tag containing the text "random content" and assigns the tag a css class called +very_important+.
    #   <%= list.tag :div, class: "very_important" 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

  def sorted_children
    children = obj.toclist
    obj.has_attribute?(:child_order) ? Obj.sort_by_list(children, obj.child_order) : children
  end
end

end