# Copyright (C) 2014-2017 MongoDB, Inc.
#
# Licensed 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 Mongo
  module Operation
    module Commands

      # A MongoDB listCollections command operation.
      #
      # @example Create the listCollections command operation.
      #   ListCollections.new(db_name: 'test')
      #
      # @note A command is actually a query on the virtual '$cmd' collection.
      #
      # Initialization:
      #   param [ Hash ] spec The specifications for the command.
      #
      #   option spec :db_name [ String ] The name of the database whose list of
      #     collection names is requested.
      #   option spec :options [ Hash ] Options for the command.
      #
      # @since 2.0.0
      class ListCollections < Command

        private

        def selector
          (spec[SELECTOR] || {}).merge(
            listCollections: 1, filter: { name: { '$not' => /system\.|\$/ }}
          )
        end
      end
    end
  end
end

require 'mongo/operation/commands/list_collections/result'