# -*- coding: utf-8 -*- #
# Copyright 2020 Google LLC. 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 importing machine images in OVF format into GCE."""

from __future__ import absolute_import
from __future__ import division
from __future__ import unicode_literals

import io

from googlecloudsdk.api_lib.compute import base_classes
from googlecloudsdk.api_lib.compute import daisy_utils
from googlecloudsdk.api_lib.compute import utils
from googlecloudsdk.calliope import base
from googlecloudsdk.calliope import exceptions as calliope_exceptions
from googlecloudsdk.command_lib.compute.instances import flags as instances_flags
from googlecloudsdk.command_lib.compute.os_config import flags
from googlecloudsdk.core import log
from googlecloudsdk.core.console import console_io
from googlecloudsdk.core.resource import resource_printer


_OUTPUT_FILTER = []
_OS_UPGRADE_OPERATION_TYPE = 'os-upgrade'
_OS_CHOICES_SOURCE = [
    'windows-2008r2',
]
_OS_CHOICES_TARGET = [
    'windows-2012r2',
]

_OS_UPGRADE_PROMPT = 'The following instance will be upgraded.'


@base.ReleaseTracks(base.ReleaseTrack.ALPHA, base.ReleaseTrack.BETA)
class OsUpgrade(base.Command):
  """Upgrade a instance's OS version."""

  @classmethod
  def Args(cls, parser):
    parser.add_argument(
        '--source-os',
        required=True,
        choices=sorted(_OS_CHOICES_SOURCE),
        help='OS version of the source instance to upgrade.')
    parser.add_argument(
        '--target-os',
        required=True,
        choices=sorted(_OS_CHOICES_TARGET),
        help='Version of the OS after upgrade.')

    parser.add_argument(
        '--create-machine-backup',
        required=False,
        action='store_true',
        default=True,
        help='When enabled, a machine image is created that backs up the '
             'original state of your instance.')
    parser.add_argument(
        '--auto-rollback',
        required=False,
        action='store_true',
        help='When auto rollback is enabled, the instance and its resources '
             'are restored to their original state. Otherwise, the instance '
             'and any temporary resources are left in the intermediate state '
             'of the time of failure. This is useful for debugging.')
    parser.add_argument(
        '--use-staging-install-media',
        required=False,
        action='store_true',
        help='Use staging install media. This flag is for testing only. Set to '
             'true to upgrade with staging windows install media.',
        hidden=True)

    daisy_utils.AddCommonDaisyArgs(parser)
    daisy_utils.AddExtraCommonDaisyArgs(parser)

    flags.INSTANCES_ARG_FOR_OS_UPGRADE.AddArgument(
        parser, operation_type=_OS_UPGRADE_OPERATION_TYPE)

  def _ValidateArgs(self, args, compute_client):
    daisy_utils.ValidateZone(args, compute_client)

  def Run(self, args):
    holder = base_classes.ComputeApiHolder(self.ReleaseTrack())
    client = holder.client
    self._ValidateArgs(args, client)

    ref = flags.INSTANCES_ARG_FOR_OS_UPGRADE.ResolveAsResource(
        args, holder.resources,
        scope_lister=instances_flags.GetInstanceZoneScopeLister(client))
    instance_uri = 'projects/{0}/zones/{1}/instances/{2}'.format(
        ref.project, ref.zone, ref.Name())

    _PromptForUpgrade(ref, args)

    log.warning('Upgrading OS. This usually takes around 40 minutes but may '
                'take up to 90 minutes.')

    return daisy_utils.RunOsUpgradeBuild(
        args=args,
        output_filter=_OUTPUT_FILTER,
        instance_uri=instance_uri,
        release_track=self.ReleaseTrack().id.lower()
        if self.ReleaseTrack() else None
    )


OsUpgrade.detailed_help = {
    'brief': 'Upgrade the instance''s OS version.',
    'DESCRIPTION':
        """\
      *{command}* upgrades the instance's OS version.

      OS Upgrade involves:
      *  Create a snapshot and/or machine image for the instance.
      *  Create an install media disk and attach it to the instance.
      *  Upgrade the OS version.
      *  Cleanup install media disk after upgrade.

      Virtual instances, snapshots, machine images, and disks in Compute Engine
      and files stored on Cloud Storage incur charges. See [](https://cloud.google.com/compute/docs/images/importing-virtual-disks#resource_cleanup).
      """,
    'EXAMPLES':
        """\
      To upgrade a instance named `my-instance` from windows-2008r2 to windows-2012r2, run:

        $ {command} my-instance --source-os=windows-2008r2 --target-os=windows-2012r2
      """,
}


def _PromptForUpgrade(ref, args):
  """Prompts the user to confirm upgrade of instance."""
  scope_name = 'zone'
  resource_type = utils.CollectionToResourceType(ref.Collection())
  resource_name = utils.CamelCaseToOutputFriendly(resource_type)

  prompt_item = '[{0}] in [{1}]'.format(ref.Name(), getattr(ref, scope_name))
  prompt_title = 'The following {0} will be upgraded from {1} to {2}:'.format(
      resource_name, args.source_os, args.target_os)

  buf = io.StringIO()
  fmt = 'list[title="{title}",always-display-title]'.format(title=prompt_title)
  resource_printer.Print(prompt_item, fmt, out=buf)
  prompt_message = buf.getvalue()

  if not console_io.PromptContinue(message=prompt_message):
    raise calliope_exceptions.ToolException('Upgrade aborted by user.')
