# Copyright 2014 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.
"""Command for removing metadata."""
from __future__ import absolute_import
from __future__ import unicode_literals
from apitools.base.py import encoding

from googlecloudsdk.api_lib.compute import base_classes
from googlecloudsdk.api_lib.compute import metadata_utils
from googlecloudsdk.calliope import arg_parsers
from googlecloudsdk.calliope import base
from googlecloudsdk.calliope import exceptions as calliope_exceptions
from googlecloudsdk.command_lib.compute.instances import flags
from googlecloudsdk.core import log


class InstancesRemoveMetadata(base.UpdateCommand):
  """Remove instance metadata.

  {command} can be used to remove instance metadata entries.
  """

  @staticmethod
  def Args(parser):
    flags.INSTANCE_ARG.AddArgument(
        parser, operation_type='set metadata on')
    group = parser.add_mutually_exclusive_group()
    group.add_argument(
        '--all',
        action='store_true',
        default=False,
        help='If provided, all metadata entries are removed.')
    group.add_argument(
        '--keys',
        type=arg_parsers.ArgList(min_length=1),
        metavar='KEY',
        help='The keys of the entries to remove.')

  def CreateReference(self, client, resources, args):
    return flags.INSTANCE_ARG.ResolveAsResource(
        args, resources, scope_lister=flags.GetInstanceZoneScopeLister(client))

  def GetGetRequest(self, client, instance_ref):
    return (client.apitools_client.instances,
            'Get',
            client.messages.ComputeInstancesGetRequest(**instance_ref.AsDict()))

  def GetSetRequest(self, client, instance_ref, replacement):
    return (client.apitools_client.instances,
            'SetMetadata',
            client.messages.ComputeInstancesSetMetadataRequest(
                metadata=replacement.metadata,
                **instance_ref.AsDict()))

  def Modify(self, client, args, existing):
    new_object = encoding.CopyProtoMessage(existing)
    existing_metadata = getattr(existing, 'metadata', None)
    new_object.metadata = metadata_utils.RemoveEntries(
        client.messages,
        existing_metadata=existing_metadata,
        keys=args.keys,
        remove_all=args.all)

    if metadata_utils.MetadataEqual(existing_metadata, new_object.metadata):
      return None
    else:
      return new_object

  def Run(self, args):
    if not args.all and not args.keys:
      raise calliope_exceptions.ToolException(
          'One of [--all] or [--keys] must be provided.')

    holder = base_classes.ComputeApiHolder(self.ReleaseTrack())
    client = holder.client

    instance_ref = self.CreateReference(client, holder.resources, args)
    get_request = self.GetGetRequest(client, instance_ref)

    objects = client.MakeRequests([get_request])

    new_object = self.Modify(client, args, objects[0])

    # If existing object is equal to the proposed object or if
    # Modify() returns None, then there is no work to be done, so we
    # print the resource and return.
    if not new_object or objects[0] == new_object:
      log.status.Print(
          'No change requested; skipping update for [{0}].'.format(
              objects[0].name))
      return objects

    return client.MakeRequests(
        [self.GetSetRequest(client, instance_ref, new_object)])
