# -*- 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.
"""Cloud Spanner backups API helper."""

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

from googlecloudsdk.api_lib.util import apis
from googlecloudsdk.calliope import exceptions as c_exceptions
from googlecloudsdk.command_lib.spanner.resource_args import CloudKmsKeyName
from googlecloudsdk.core import exceptions as core_exceptions
from googlecloudsdk.core.credentials import requests
from googlecloudsdk.core.util import times
from six.moves import http_client as httplib
from six.moves import urllib


class HttpRequestFailedError(core_exceptions.Error):
  """Indicates that the http request failed in some way."""
  pass


# General Utils
def ParseExpireTime(expiration_value):
  """Parse flag value into Datetime format for expireTime."""
  # expiration_value could be in Datetime format or Duration format.
  datetime = (
      times.ParseDuration(expiration_value).GetRelativeDateTime(
          times.Now(times.UTC)))
  parsed_datetime = times.FormatDateTime(
      datetime, '%Y-%m-%dT%H:%M:%S.%6f%Ez', tzinfo=times.UTC)
  return parsed_datetime


def CheckAndGetExpireTime(args):
  """Check if fields for expireTime are correctly specified and parse value."""

  # User can only specify either expiration_date or retention_period, not both.
  if (args.IsSpecified('expiration_date') and
      args.IsSpecified('retention_period')) or not(
          args.IsSpecified('expiration_date') or
          args.IsSpecified('retention_period')):
    raise c_exceptions.InvalidArgumentException(
        '--expiration-date or --retention-period',
        'Must specify either --expiration-date or --retention-period.')
  if args.expiration_date:
    return args.expiration_date
  elif args.retention_period:
    return ParseExpireTime(args.retention_period)


def GetBackup(backup_ref):
  """Get a backup."""
  client = apis.GetClientInstance('spanner', 'v1')
  msgs = apis.GetMessagesModule('spanner', 'v1')
  req = msgs.SpannerProjectsInstancesBackupsGetRequest(
      name=backup_ref.RelativeName())
  return client.projects_instances_backups.Get(req)


def CreateBackup(
    backup_ref, args, encryption_type=None, kms_key: CloudKmsKeyName = None
):
  """Create a new backup."""
  client = apis.GetClientInstance('spanner', 'v1')
  msgs = apis.GetMessagesModule('spanner', 'v1')

  query_params = {'alt': 'json', 'backupId': args.backup}
  if encryption_type:
    query_params['encryptionConfig.encryptionType'] = encryption_type
  if kms_key:
    if kms_key.kms_key_name:
      query_params['encryptionConfig.kmsKeyName'] = kms_key.kms_key_name
    elif kms_key.kms_key_names:
      query_params['encryptionConfig.kmsKeyNames'] = kms_key.kms_key_names
  parent = backup_ref.Parent().RelativeName()
  url = '{}v1/{}/backups?{}'.format(
      client.url, parent, urllib.parse.urlencode(query_params, doseq=True)
  )
  backup = msgs.Backup(
      database=parent + '/databases/' + args.database,
      expireTime=CheckAndGetExpireTime(args))
  if args.IsSpecified('version_time'):
    backup.versionTime = args.version_time

  # We are not using `SpannerProjectsInstancesBackupsCreateRequest` from
  # `spanner_v1_messages.py` because `apitools` does not generate nested proto
  # messages correctly, b/31244944. Here, an `EncryptionConfig` should be a
  # nested proto, rather than `EncryptionConfig_kmsKeyName` being a
  # field(http://shortn/_gHieB9ir83). Thus, this workaround is necessary and
  # will be here to stay since `apitools` is not under active development and
  # gcloud will continue to support `apitools` http://shortn/_BJJCZbnCFp.
  # Make an http request directly instead of using the apitools client which
  # does not support '.' characters in query parameters (b/31244944).
  http_client = requests.GetSession()
  # Workaround since gcloud cannot handle HttpBody properly (b/31403673).
  http_client.encoding = 'utf-8'
  response = http_client.request(
      'POST', url, data=client.SerializeMessage(backup)
  )
  if int(response.status_code) != httplib.OK:
    raise HttpRequestFailedError(
        'HTTP request failed. Response: ' + response.text
    )
  message_type = getattr(msgs, 'Operation')
  return client.DeserializeMessage(message_type, response.content)


def CopyBackup(source_backup_ref,
               destination_backup_ref,
               args,
               encryption_type=None,
               kms_key=None):
  """Copy a backup."""
  client = apis.GetClientInstance('spanner', 'v1')
  msgs = apis.GetMessagesModule('spanner', 'v1')
  copy_backup_request = msgs.CopyBackupRequest(
      backupId=destination_backup_ref.Name(),
      sourceBackup=source_backup_ref.RelativeName())
  copy_backup_request.expireTime = CheckAndGetExpireTime(args)
  if kms_key:
    copy_backup_request.encryptionConfig = msgs.CopyBackupEncryptionConfig(
        encryptionType=encryption_type,
        kmsKeyName=kms_key.kms_key_name,
        kmsKeyNames=kms_key.kms_key_names,
    )
  elif encryption_type:
    copy_backup_request.encryptionConfig = msgs.CopyBackupEncryptionConfig(
        encryptionType=encryption_type,
    )

  req = msgs.SpannerProjectsInstancesBackupsCopyRequest(
      parent=destination_backup_ref.Parent().RelativeName(),
      copyBackupRequest=copy_backup_request)
  return client.projects_instances_backups.Copy(req)


def ModifyUpdateMetadataRequest(backup_ref, args, req):
  """Parse arguments and construct update backup request."""
  req.backup.name = backup_ref.Parent().RelativeName(
  ) + '/backups/' + args.backup
  req.backup.expireTime = CheckAndGetExpireTime(args)
  req.updateMask = 'expire_time'
  return req


def ModifyListRequest(instance_ref, args, req):
  """Parse arguments and construct list backups request."""
  req.parent = instance_ref.RelativeName()
  if args.database:
    database = instance_ref.RelativeName() + '/databases/' + args.database
    req.filter = 'database="{}"'.format(database)
  return req


def CheckBackupExists(backup_ref, _, req):
  """Checks if backup exists, if so, returns request."""

  # The delete API returns a 200 regardless of whether the backup being
  # deleted exists. In order to show users feedback for incorrectly
  # entered backup names, we have to make a request to check if the backup
  # exists. If the backup exists, it's deleted, otherwise, we display the
  # error from backups.Get.
  GetBackup(backup_ref)
  return req


def FormatListBackups(backup_refs, _):
  """Formats existing fields for displaying them in the list response.

  Args:
    backup_refs: A list of backups.

  Returns:
    The list of backups with the new formatting.
  """
  return [_FormatBackup(backup_ref) for backup_ref in backup_refs]


def _FormatBackup(backup_ref):
  """Formats a single backup for displaying it in the list response.

  This function makes in-place modifications.

  Args:
    backup_ref: The backup to format.

  Returns:
    The backup with the new formatting.
  """
  formatted_backup_ref = backup_ref
  formatted_backup_ref.backupSchedules = [
      _ExtractScheduleNameFromScheduleUri(schedule_uri)
      for schedule_uri in backup_ref.backupSchedules
  ]
  formatted_backup_ref.instancePartitions = [
      _ExtractInstancePartitionNameFromInstancePartitionUri(
          instance_partition.instancePartition
      )
      for instance_partition in backup_ref.instancePartitions
  ]
  return formatted_backup_ref


def _ExtractScheduleNameFromScheduleUri(schedule_uri):
  """Converts a schedule URI to an schedule name.

  Args:
      schedule_uri: The URI of the schedule, e.g.,
      "projects/test-project/instances/test-instance/databases/test-database/backupSchedules/test-backup-schedule".

  Returns:
      The name of the schedule ("test-backup-schedule" in the example above).
  """
  return schedule_uri.split('/')[-1]


def _ExtractInstancePartitionNameFromInstancePartitionUri(
    instance_partition_uri,
):
  """Converts an instance partition URI to an instance partition name.

  Args:
      instance_partition_uri: The URI of an instance partition, e.g.,
        "projects/test-project/instances/test-instance/instancePartitions/test-instance-partition".

  Returns:
      The name of the instance partition ("test-instance-partition" in the
      example above).
  """
  return {'instancePartition': instance_partition_uri.split('/')[-1]}