# Copyright 2020 Google LLC
#
# 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
#
#     https://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 "google/cloud/spanner/status"
require "google/cloud/spanner/backup/job/list"

module Google
  module Cloud
    module Spanner
      class Backup
        ##
        # # Job
        #
        # A resource representing the long-running, asynchronous processing of
        # backup creation. The job can be refreshed to retrieve the backup
        # object once the operation has been completed.
        #
        # See {Google::Cloud::Spanner::Database#create_backup}
        #
        # @see https://cloud.google.com/spanner/reference/rpc/google.longrunning#google.longrunning.Operation
        #   Long-running Operation
        #
        # @example
        #   require "google/cloud/spanner"
        #
        #   spanner = Google::Cloud::Spanner.new
        #
        #   database = spanner.database "my-instance", "my-database"
        #   expire_time = Time.now + 36000
        #   job = database.create_backup "my-backup", expire_time
        #
        #   job.done? #=> false
        #   job.reload! # API call
        #   job.done? #=> true
        #
        #   if job.error?
        #     status = job.error
        #   else
        #     backup = job.backup
        #   end
        #
        class Job
          ##
          # @private The `Gapic::Operation` gRPC object.
          attr_accessor :grpc

          ##
          # @private The gRPC Service object.
          attr_accessor :service

          ##
          # @private Creates a new Backup::Job instance.
          def initialize
            @grpc = nil
            @service = nil
          end

          ##
          # The backup is the object of the operation.
          #
          # @return [Backup, nil] The backup, or
          #   `nil` if the operation is not complete.
          #
          # @example
          #   require "google/cloud/spanner"
          #
          #   spanner = Google::Cloud::Spanner.new
          #
          #   database = spanner.database "my-instance", "my-database"
          #   expire_time = Time.now + 36000
          #   job = database.create_backup "my-backup", expire_time
          #
          #   job.done? #=> false
          #   job.reload!
          #   job.done? #=> true
          #   backup = job.backup
          #
          def backup
            return nil unless done?
            return nil unless @grpc.grpc_op.result == :response
            Backup.from_grpc @grpc.results, service
          end

          ##
          # Checks if the processing of the backup operation is complete.
          #
          # @return [boolean] `true` when complete, `false` otherwise.
          #
          # @example
          #   require "google/cloud/spanner"
          #
          #   spanner = Google::Cloud::Spanner.new
          #
          #   database = spanner.database "my-instance", "my-database"
          #   expire_time = Time.now + 36000
          #   job = database.create_backup "my-backup", expire_time
          #
          #   job.done? #=> false
          #
          def done?
            @grpc.done?
          end

          ##
          # Checks if the processing of the backup operation has errored.
          #
          # @return [boolean] `true` when errored, `false` otherwise.
          #
          # @example
          #   require "google/cloud/spanner"
          #
          #   spanner = Google::Cloud::Spanner.new
          #
          #   database = spanner.database "my-instance", "my-database"
          #   expire_time = Time.now + 36000
          #   job = database.create_backup "my-backup", expire_time
          #
          #   job.error? #=> false
          #
          def error?
            @grpc.error?
          end

          ##
          # The status if the operation associated with this job produced an
          # error.
          #
          # @return [Google::Cloud::Spanner::Status, nil] A status object with
          #   the status code and message, or `nil` if no error occurred.
          #
          # @example
          #   require "google/cloud/spanner"
          #
          #   spanner = Google::Cloud::Spanner.new
          #
          #   database = spanner.database "my-instance", "my-database"
          #   expire_time = Time.now + 36000
          #   job = database.create_backup "my-backup", expire_time
          #
          #   job.error? # true
          #
          #   error = job.error
          #
          def error
            return nil unless error?
            Google::Cloud::Spanner::Status.from_grpc @grpc.error
          end

          ##
          # Reloads the job with current data from the long-running,
          # asynchronous processing of a backup operation.
          #
          # @return [Google::Cloud::Spanner::Backup::Job] The same job
          #   instance.
          #
          # @example
          #   require "google/cloud/spanner"
          #
          #   spanner = Google::Cloud::Spanner.new
          #
          #   database = spanner.database "my-instance", "my-database"
          #   expire_time = Time.now + 36000
          #   job = database.create_backup "my-backup", expire_time
          #
          #   job.done? #=> false
          #   job.reload! # API call
          #   job.done? #=> true
          #
          def reload!
            @grpc.reload!
            self
          end
          alias refresh! reload!

          ##
          # Reloads the job until the operation is complete. The delay between
          # reloads will incrementally increase.
          #
          # @example
          #   require "google/cloud/spanner"
          #
          #   spanner = Google::Cloud::Spanner.new
          #
          #   database = spanner.database "my-instance", "my-database"
          #   expire_time = Time.now + 36000
          #   job = database.create_backup "my-backup", expire_time
          #
          #   job.done? #=> false
          #   job.wait_until_done!
          #   job.done? #=> true
          #
          def wait_until_done!
            @grpc.wait_until_done!
          end

          ##
          # Cancel the backup job.
          #
          # @example
          #   require "google/cloud/spanner"
          #
          #   spanner = Google::Cloud::Spanner.new
          #
          #   database = spanner.database "my-instance", "my-database"
          #   expire_time = Time.now + 36000
          #   job = database.create_backup "my-backup", expire_time
          #
          #   job.done? #=> false
          #   job.cancel
          #
          def cancel
            @grpc.cancel
          end

          ##
          # The operation progress in percentage.
          #
          # @return [Integer]
          def progress_percent
            @grpc.metadata.progress.progress_percent
          end

          ##
          # The operation start time.
          #
          # @return [Time, nil]
          def start_time
            return nil unless @grpc.metadata.progress.start_time
            Convert.timestamp_to_time @grpc.metadata.progress.start_time
          end

          ##
          # The operation end time.
          #
          # @return [Time, nil]
          def end_time
            return nil unless @grpc.metadata.progress.end_time
            Convert.timestamp_to_time @grpc.metadata.progress.end_time
          end

          ##
          # The operation canceled time.
          #
          # @return [Time, nil]
          def cancel_time
            return nil unless @grpc.metadata.cancel_time
            Convert.timestamp_to_time @grpc.metadata.cancel_time
          end

          ##
          # @private New Backup::Job from a `Gapic::Operation` object.
          def self.from_grpc grpc, service
            new.tap do |job|
              job.instance_variable_set :@grpc, grpc
              job.instance_variable_set :@service, service
            end
          end
        end
      end
    end
  end
end