# frozen_string_literal: true

# Copyright (C) 2019-2021 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 Crypt
    module KMS
      module AWS
        # AWS KMS Credentials object contains credentials for using AWS KMS provider.
        #
        # @api private
        class Credentials
          extend Forwardable
          include KMS::Validations

          # @return [ String ] AWS access key.
          attr_reader :access_key_id

          # @return [ String ] AWS secret access key.
          attr_reader :secret_access_key

          # @return [ String | nil ] AWS session token.
          attr_reader :session_token

          # @api private
          def_delegator :@opts, :empty?

          FORMAT_HINT = 'AWS KMS provider options must be in the format: ' +
                        "{ access_key_id: 'YOUR-ACCESS-KEY-ID', secret_access_key: 'SECRET-ACCESS-KEY' }"

          # Creates an AWS KMS credentials object form a parameters hash.
          #
          # @param [ Hash ] opts A hash that contains credentials for
          #   AWS KMS provider
          # @option opts [ String ] :access_key_id AWS access key id.
          # @option opts [ String ] :secret_access_key AWS secret access key.
          # @option opts [ String | nil ] :session_token AWS session token, optional.
          #
          # @raise [ ArgumentError ] If required options are missing or incorrectly
          #   formatted.
          def initialize(opts)
            @opts = opts
            return if empty?

            @access_key_id = validate_param(:access_key_id, opts, FORMAT_HINT)
            @secret_access_key = validate_param(:secret_access_key, opts, FORMAT_HINT)
            @session_token = validate_param(:session_token, opts, FORMAT_HINT, required: false)
          end

          # Convert credentials object to a BSON document in libmongocrypt format.
          #
          # @return [ BSON::Document ] AWS KMS credentials in libmongocrypt format.
          def to_document
            return BSON::Document.new if empty?

            BSON::Document.new({
                                 accessKeyId: access_key_id,
                                 secretAccessKey: secret_access_key,
                               }).tap do |bson|
              bson.update({ sessionToken: session_token }) unless session_token.nil?
            end
          end
        end
      end
    end
  end
end
