# frozen_string_literal: true

# Copyright (C) 2015-2020 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
    class Find
      module Builder
        # Provides behavior for converting Ruby options to wire protocol flags
        # when sending find and related commands (e.g. explain).
        #
        # @api private
        module Flags
          # Options to cursor flags mapping.
          MAPPINGS = {
            allow_partial_results: [ :partial ],
            oplog_replay: [ :oplog_replay ],
            no_cursor_timeout: [ :no_cursor_timeout ],
            tailable: [ :tailable_cursor ],
            tailable_await: %i[await_data tailable_cursor],
            await_data: [ :await_data ],
            exhaust: [ :exhaust ],
          }.freeze

          # Converts Ruby find options to an array of flags.
          #
          # Any keys in the input hash that are not options that map to flags
          # are ignored.
          #
          # @param [ Hash, BSON::Document ] options The options.
          #
          # @return [ Array<Symbol> ] The flags.
          module_function def map_flags(options)
            MAPPINGS.each.each_with_object(options[:flags] || []) do |(key, value), flags|
              cursor_type = options[:cursor_type]
              flags.push(*value) if options[key] || (cursor_type && cursor_type == key)
            end
          end
        end
      end
    end
  end
end
