# Licensed to Elasticsearch B.V. under one or more contributor
# license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright
# ownership. Elasticsearch B.V. licenses this file to you under
# the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

module Elasticsearch
  module DSL
    module Search
      module Aggregations

        # A single-bucket aggregation which allows to aggregate on "parent" documents
        # from the nested documents
        #
        # @example
        #
        #     search do
        #       aggregation :offers do
        #         nested do
        #           path 'offers'
        #           aggregation :top_categories do
        #             reverse_nested do
        #               aggregation :top_category_per_offer do
        #                 terms field: 'category'
        #               end
        #             end
        #           end
        #         end
        #       end
        #     end
        #
        # See the integration test for a full example.
        #
        # @see http://elasticsearch.org/guide/en/elasticsearch/guide/current/nested-aggregation.html
        #
        class ReverseNested
          include BaseAggregationComponent
        end

      end
    end
  end
end