# -*- coding: utf-8 -*-
#
# Copyright 2019 Google LLC
#
# 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
#
#     https://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.


import google.api_core.grpc_helpers
import google.api_core.operations_v1

from google.cloud.automl_v1beta1.proto import prediction_service_pb2_grpc


class PredictionServiceGrpcTransport(object):
    """gRPC transport class providing stubs for
    google.cloud.automl.v1beta1 PredictionService API.

    The transport provides access to the raw gRPC stubs,
    which can be used to take advantage of advanced
    features of gRPC.
    """

    # The scopes needed to make gRPC calls to all of the methods defined
    # in this service.
    _OAUTH_SCOPES = ("https://www.googleapis.com/auth/cloud-platform",)

    def __init__(
        self, channel=None, credentials=None, address="automl.googleapis.com:443"
    ):
        """Instantiate the transport class.

        Args:
            channel (grpc.Channel): A ``Channel`` instance through
                which to make calls. This argument is mutually exclusive
                with ``credentials``; providing both will raise an exception.
            credentials (google.auth.credentials.Credentials): The
                authorization credentials to attach to requests. These
                credentials identify this application to the service. If none
                are specified, the client will attempt to ascertain the
                credentials from the environment.
            address (str): The address where the service is hosted.
        """
        # If both `channel` and `credentials` are specified, raise an
        # exception (channels come with credentials baked in already).
        if channel is not None and credentials is not None:
            raise ValueError(
                "The `channel` and `credentials` arguments are mutually " "exclusive."
            )

        # Create the channel.
        if channel is None:
            channel = self.create_channel(address=address, credentials=credentials)

        self._channel = channel

        # gRPC uses objects called "stubs" that are bound to the
        # channel and provide a basic method for each RPC.
        self._stubs = {
            "prediction_service_stub": prediction_service_pb2_grpc.PredictionServiceStub(
                channel
            )
        }

        # Because this API includes a method that returns a
        # long-running operation (proto: google.longrunning.Operation),
        # instantiate an LRO client.
        self._operations_client = google.api_core.operations_v1.OperationsClient(
            channel
        )

    @classmethod
    def create_channel(
        cls, address="automl.googleapis.com:443", credentials=None, **kwargs
    ):
        """Create and return a gRPC channel object.

        Args:
            address (str): The host for the channel to use.
            credentials (~.Credentials): The
                authorization credentials to attach to requests. These
                credentials identify this application to the service. If
                none are specified, the client will attempt to ascertain
                the credentials from the environment.
            kwargs (dict): Keyword arguments, which are passed to the
                channel creation.

        Returns:
            grpc.Channel: A gRPC channel object.
        """
        return google.api_core.grpc_helpers.create_channel(
            address, credentials=credentials, scopes=cls._OAUTH_SCOPES, **kwargs
        )

    @property
    def channel(self):
        """The gRPC channel used by the transport.

        Returns:
            grpc.Channel: A gRPC channel object.
        """
        return self._channel

    @property
    def predict(self):
        """Return the gRPC stub for :meth:`PredictionServiceClient.predict`.

        Perform an online prediction. The prediction result will be directly
        returned in the response. Available for following ML problems, and their
        expected request payloads:

        -  Image Classification - Image in .JPEG, .GIF or .PNG format,
           image\_bytes up to 30MB.
        -  Image Object Detection - Image in .JPEG, .GIF or .PNG format,
           image\_bytes up to 30MB.
        -  Text Classification - TextSnippet, content up to 60,000 characters,
           UTF-8 encoded.
        -  Text Extraction - TextSnippet, content up to 30,000 characters, UTF-8
           NFC encoded.
        -  Translation - TextSnippet, content up to 25,000 characters, UTF-8
           encoded.
        -  Tables - Row, with column values matching the columns of the model,
           up to 5MB. Not available for FORECASTING

        ``prediction_type``.

        Returns:
            Callable: A callable which accepts the appropriate
                deserialized request object and returns a
                deserialized response object.
        """
        return self._stubs["prediction_service_stub"].Predict

    @property
    def batch_predict(self):
        """Return the gRPC stub for :meth:`PredictionServiceClient.batch_predict`.

        Perform a batch prediction. Unlike the online ``Predict``, batch
        prediction result won't be immediately available in the response.
        Instead, a long running operation object is returned. User can poll the
        operation result via ``GetOperation`` method. Once the operation is
        done, ``BatchPredictResult`` is returned in the ``response`` field.
        Available for following ML problems:

        -  Video Classification
        -  Video Object Tracking
        -  Text Extraction
        -  Tables

        Returns:
            Callable: A callable which accepts the appropriate
                deserialized request object and returns a
                deserialized response object.
        """
        return self._stubs["prediction_service_stub"].BatchPredict
