text: # Copyright 2017 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.
  
  """Helpers for batch requests to the Google Cloud Firestore API."""
  
  
  from google.cloud.firestore_v1 import _helpers
  
  
  class WriteBatch(object):
      """Accumulate write operations to be sent in a batch.
  
      This has the same set of methods for write operations that
      :class:`~google.cloud.firestore_v1.document.DocumentReference` does,
      e.g. :meth:`~google.cloud.firestore_v1.document.DocumentReference.create`.
  
      Args:
          client (:class:`~google.cloud.firestore_v1.client.Client`):
              The client that created this batch.
      """
  
      def __init__(self, client):
          self._client = client
          self._write_pbs = []
          self.write_results = None
          self.commit_time = None
  
      def _add_write_pbs(self, write_pbs):
          """Add `Write`` protobufs to this transaction.
  
          This method intended to be over-ridden by subclasses.
  
          Args:
              write_pbs (List[google.cloud.proto.firestore.v1.\
                  write_pb2.Write]): A list of write protobufs to be added.
          """
          self._write_pbs.extend(write_pbs)
  
      def create(self, reference, document_data):
          """Add a "change" to this batch to create a document.
  
          If the document given by ``reference`` already exists, then this
          batch will fail when :meth:`commit`-ed.
  
          Args:
              reference (:class:`~google.cloud.firestore_v1.document.DocumentReference`):
                  A document reference to be created in this batch.
              document_data (dict): Property names and values to use for
                  creating a document.
          """
          write_pbs = _helpers.pbs_for_create(reference._document_path, document_data)
          self._add_write_pbs(write_pbs)
  
      def set(self, reference, document_data, merge=False):
          """Add a "change" to replace a document.
  
          See
          :meth:`google.cloud.firestore_v1.document.DocumentReference.set` for
          more information on how ``option`` determines how the change is
          applied.
  
          Args:
              reference (:class:`~google.cloud.firestore_v1.document.DocumentReference`):
                  A document reference that will have values set in this batch.
              document_data (dict):
                  Property names and values to use for replacing a document.
              merge (Optional[bool] or Optional[List<apispec>]):
                  If True, apply merging instead of overwriting the state
                  of the document.
          """
          if merge is not False:
              write_pbs = _helpers.pbs_for_set_with_merge(
                  reference._document_path, document_data, merge
              )
          else:
              write_pbs = _helpers.pbs_for_set_no_merge(
                  reference._document_path, document_data
              )
  
          self._add_write_pbs(write_pbs)
  
      def update(self, reference, field_updates, option=None):
          """Add a "change" to update a document.
  
          See
          :meth:`google.cloud.firestore_v1.document.DocumentReference.update`
          for more information on ``field_updates`` and ``option``.
  
          Args:
              reference (:class:`~google.cloud.firestore_v1.document.DocumentReference`):
                  A document reference that will be updated in this batch.
              field_updates (dict):
                  Field names or paths to update and values to update with.
              option (Optional[:class:`~google.cloud.firestore_v1.client.WriteOption`]):
                  A write option to make assertions / preconditions on the server
                  state of the document before applying changes.
          """
          if option.__class__.__name__ == "ExistsOption":
              raise ValueError("you must not pass an explicit write option to " "update.")
          write_pbs = _helpers.pbs_for_update(
              reference._document_path, field_updates, option
          )
          self._add_write_pbs(write_pbs)
  
      def delete(self, reference, option=None):
          """Add a "change" to delete a document.
  
          See
          :meth:`google.cloud.firestore_v1.document.DocumentReference.delete`
          for more information on how ``option`` determines how the change is
          applied.
  
          Args:
              reference (:class:`~google.cloud.firestore_v1.document.DocumentReference`):
                  A document reference that will be deleted in this batch.
              option (Optional[:class:`~google.cloud.firestore_v1.client.WriteOption`]):
                  A write option to make assertions / preconditions on the server
                  state of the document before applying changes.
          """
          write_pb = _helpers.pb_for_delete(reference._document_path, option)
          self._add_write_pbs([write_pb])
  
      def commit(self):
          """Commit the changes accumulated in this batch.
  
          Returns:
              List[:class:`google.cloud.proto.firestore.v1.write_pb2.WriteResult`, ...]:
              The write results corresponding to the changes committed, returned
              in the same order as the changes were applied to this batch. A
              write result contains an ``update_time`` field.
          """
          commit_response = self._client._firestore_api.commit(
              self._client._database_string,
              self._write_pbs,
              transaction=None,
              metadata=self._client._rpc_metadata,
          )
  
          self._write_pbs = []
          self.write_results = results = list(commit_response.write_results)
          self.commit_time = commit_response.commit_time
          return results
  
      def __enter__(self):
          return self
  
      def __exit__(self, exc_type, exc_value, traceback):
          if exc_type is None:
              self.commit()
  