# Copyright 2016 Google Inc. All rights reserved.
#
# 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.


require "delegate"

module Gcloud
  module Logging
    class ResourceDescriptor
      ##
      # ResourceDescriptor::List is a special case Array with additional values.
      class List < DelegateClass(::Array)
        ##
        # If not empty, indicates that there are more records that match
        # the request and this value should be passed to continue.
        attr_accessor :token

        ##
        # @private Create a new ResourceDescriptor::List with an array of
        # ResourceDescriptor instances.
        def initialize arr = []
          super arr
        end

        ##
        # Whether there is a next page of resource descriptors.
        def next?
          !token.nil?
        end

        ##
        # Retrieve the next page of resource descriptors.
        def next
          return nil unless next?
          ensure_service!
          list_grpc = @service.list_resource_descriptors token: token
          self.class.from_grpc list_grpc, @service
        rescue GRPC::BadStatus => e
          raise Gcloud::Error.from_error(e)
        end

        ##
        # @private New ResourceDescriptor::List from a
        # Google::Logging::V2::ListMonitoredResourceDescriptorsResponse object.
        def self.from_grpc grpc_list, service
          sinks = new(Array(grpc_list.resource_descriptors).map do |grpc|
            ResourceDescriptor.from_grpc grpc
          end)
          sinks.instance_eval do
            @token = grpc_list.next_page_token
            @token = nil if @token == ""
            @service = service
          end
          sinks
        end

        protected

        ##
        # Raise an error unless an active service is available.
        def ensure_service!
          fail "Must have active service" unless @service
        end
      end
    end
  end
end