# -*- coding: utf-8 -*- #
# Copyright 2019 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 retrieving a screenshot from the designated instance."""

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

import base64
import sys

from googlecloudsdk.api_lib.compute import base_classes
from googlecloudsdk.calliope import base
from googlecloudsdk.command_lib.compute.instances import flags
from googlecloudsdk.core import log
from googlecloudsdk.core.util import files

_DETAILED_HELP = {
    'DESCRIPTION':
        ("Capture a screenshot (JPEG image) of the virtual machine instance's "
         "display."),
    'EXAMPLES':
        """\
        To get a screenshot from an instance named ``{0}'', run:

          $ {1} {0} --destination=output.jpg

        """.format('test-instance', '{command}'),
}


@base.ReleaseTracks(base.ReleaseTrack.BETA, base.ReleaseTrack.GA)
class GetScreenshot(base.Command):
  """Capture a screenshot (JPEG image) of the virtual machine instance's display."""

  detailed_help = _DETAILED_HELP
  _display_output = False

  @staticmethod
  def Args(parser):
    flags.INSTANCE_ARG.AddArgument(
        parser, operation_type='get a screenshot from')
    parser.add_argument(
        '--destination',
        help=('Filename, including the path, to save the screenshot '
              '(JPEG image).'))

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

  def _GetInstance(self, holder, instance_ref):
    request = holder.client.messages.ComputeInstancesGetRequest(
        **instance_ref.AsDict())
    return holder.client.MakeRequests([(holder.client.apitools_client.instances,
                                        'Get', request)])[0]

  def Run(self, args):
    holder = base_classes.ComputeApiHolder(self.ReleaseTrack())
    instance_ref = self._GetInstanceRef(holder, args)
    request = holder.client.messages.ComputeInstancesGetScreenshotRequest(
        **instance_ref.AsDict())

    response = holder.client.MakeRequests([
        (holder.client.apitools_client.instances, 'GetScreenshot', request)
    ])[0]

    self._display_file_output = False
    if args.IsSpecified('destination'):
      with files.BinaryFileWriter(args.destination) as output:
        output.write(base64.b64decode(response.contents))
      self._resource_name = instance_ref.instance
      self._destination = args.destination
      self._display_file_output = True
    else:
      self._response_contents = response.contents
    return

  def Epilog(self, resources_were_displayed=False):
    if self._display_file_output:
      log.status.Print("Output screenshot for [{}] to '{}'.".format(
          self._resource_name, self._destination))
    else:
      sys.stdout.buffer.write(base64.b64decode(self._response_contents))