class RevisionAccepter < Revision

  attr_reader :version, :versionable
  def initialize(version)
    @version = version
    @versionable = version.versionable
    accept_revision
  end

  private
  def accept_revision
    create_or_update_versionable
    update_version_children
  end

  def create_or_update_versionable
    versionable.present? ? update_versionable : create_versionable
  end

  def new_attributes
    version_attributes.each_with_object({}) {|v, h| h[v.name] = v.new_value }
  end

  def create_versionable
    version.versionable = version.versionable_type.constantize.
                          create(new_attributes)
  end

  def update_versionable
    versionable.update_attributes(new_attributes)
  end

  def update_version_children
    version_children.each do |child|
      update_or_destroy_child(child)
    end
  end

  def update_or_destroy_child(child)
    if child.marked_for_removal?
      destroy_child(child)
    else
      RevisionAccepter.new(child)
    end
  end

  def destroy_child(child)
    child.versionable.destroy
  end

end