# -*- coding: utf-8 -*- #
# Copyright 2015 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.

"""A command that reads JSON data and lists it."""


import json
import sys

from googlecloudsdk.calliope import base
from googlecloudsdk.calliope import exceptions
from googlecloudsdk.core.util import files


class ListFromJson(base.ListCommand):
  """Read JSON data and list it on the standard output.

  *{command}* is a test harness for resource output formatting and filtering.
  It behaves like any other `gcloud ... list` command except that the resources
  are read from a JSON data file.

  The input JSON data is either a single resource object or a list of resource
  objects of the same type. The resources are printed on the standard output.
  The default output format is *json*.
  """

  @staticmethod
  def Args(parser):
    base.URI_FLAG.RemoveFromParser(parser)
    parser.add_argument(
        'json_file',
        metavar='JSON-FILE',
        nargs='?',
        default=None,
        help=('A file containing JSON data for a single resource or a list of'
              ' resources of the same type. If omitted then the standard input'
              ' is read.'))
    parser.display_info.AddFormat('json')
    parser.display_info.AddCacheUpdater(None)  # No resource URIs.

  def Run(self, args):
    if args.json_file:
      try:
        resources = json.loads(files.ReadFileContents(args.json_file))
      except (files.Error, ValueError) as e:
        raise exceptions.BadFileException(
            'Cannot read [{}]: {}'.format(args.json_file, e))
    else:
      try:
        resources = json.load(sys.stdin)
      except (IOError, ValueError) as e:
        raise exceptions.BadFileException(
            'Cannot read the standard input: {}'.format(e))
    return resources
