# Copyright 2016 Google Inc.
#
# 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.

import unittest

import mock


def _make_credentials():
    import google.auth.credentials

    return mock.Mock(spec=google.auth.credentials.Credentials)


def _make_result(alternatives=()):
    from google.cloud.proto.speech.v1 import cloud_speech_pb2

    return cloud_speech_pb2.SpeechRecognitionResult(
        alternatives=[
            cloud_speech_pb2.SpeechRecognitionAlternative(
                transcript=alternative['transcript'],
                confidence=alternative['confidence'],
            ) for alternative in alternatives
        ],
    )


def _make_streaming_result(alternatives=(), is_final=True, stability=1.0):
    from google.cloud.proto.speech.v1 import cloud_speech_pb2

    return cloud_speech_pb2.StreamingRecognitionResult(
        alternatives=[
            cloud_speech_pb2.SpeechRecognitionAlternative(
                transcript=alternative['transcript'],
                confidence=alternative['confidence'],
            ) for alternative in alternatives
        ],
        is_final=is_final,
        stability=stability,
    )


def _make_streaming_response(*results):
    from google.cloud.proto.speech.v1 import cloud_speech_pb2

    response = cloud_speech_pb2.StreamingRecognizeResponse(
        results=results,
    )
    return response


def _make_sync_response(*results):
    from google.cloud.proto.speech.v1 import cloud_speech_pb2

    response = cloud_speech_pb2.RecognizeResponse(
        results=results,
    )
    return response


class TestClient(unittest.TestCase):
    SAMPLE_RATE = 16000
    HINTS = ['hi']
    AUDIO_SOURCE_URI = 'gs://sample-bucket/sample-recording.flac'
    AUDIO_CONTENT = b'testing 1 2 3'

    @staticmethod
    def _get_target_class():
        from google.cloud.speech.client import Client

        return Client

    def _make_one(self, *args, **kw):
        return self._get_target_class()(*args, **kw)

    def test_ctor(self):
        creds = _make_credentials()
        http = object()
        client = self._make_one(credentials=creds, _http=http)
        self.assertTrue(client._credentials is creds)
        self.assertTrue(client._http is http)

    def test_ctor_use_grpc_preset(self):
        creds = _make_credentials()
        http = object()
        client = self._make_one(credentials=creds, _http=http, _use_grpc=True)
        self.assertTrue(client._use_grpc)

    def test_create_sample_from_client(self):
        from google.cloud import speech
        from google.cloud.speech.sample import Sample

        credentials = _make_credentials()
        client = self._make_one(credentials=credentials)

        sample = client.sample(
            source_uri=self.AUDIO_SOURCE_URI, encoding=speech.Encoding.FLAC,
            sample_rate_hertz=self.SAMPLE_RATE)
        self.assertIsInstance(sample, Sample)
        self.assertEqual(sample.source_uri, self.AUDIO_SOURCE_URI)
        self.assertEqual(sample.sample_rate_hertz, self.SAMPLE_RATE)
        self.assertEqual(sample.encoding, speech.Encoding.FLAC)

        content_sample = client.sample(
            content=self.AUDIO_CONTENT, encoding=speech.Encoding.FLAC,
            sample_rate_hertz=self.SAMPLE_RATE)
        self.assertEqual(content_sample.content, self.AUDIO_CONTENT)
        self.assertEqual(content_sample.sample_rate_hertz, self.SAMPLE_RATE)
        self.assertEqual(content_sample.encoding, speech.Encoding.FLAC)

    def test_sync_recognize_content_with_optional_params_no_gax(self):
        from base64 import b64encode

        from google.cloud._helpers import _bytes_to_unicode

        from google.cloud import speech
        from google.cloud.speech.alternative import Alternative
        from google.cloud.speech.result import Result
        from tests.unit._fixtures import SYNC_RECOGNIZE_RESPONSE

        _b64_audio_content = _bytes_to_unicode(b64encode(self.AUDIO_CONTENT))
        request = {
            'config': {
                'encoding': 'FLAC',
                'maxAlternatives': 2,
                'sampleRateHertz': 16000,
                'speechContext': {
                    'phrases': [
                        'hi',
                    ]
                },
                'languageCode': 'EN',
                'profanityFilter': True,
            },
            'audio': {
                'content': _b64_audio_content,
            }
        }
        credentials = _make_credentials()
        client = self._make_one(credentials=credentials, _use_grpc=False)
        speech_api = client.speech_api
        connection = _Connection(SYNC_RECOGNIZE_RESPONSE)
        speech_api._connection = connection

        encoding = speech.Encoding.FLAC

        sample = client.sample(
            content=self.AUDIO_CONTENT, encoding=encoding,
            sample_rate_hertz=self.SAMPLE_RATE)

        response = sample.recognize(
            language_code='EN', max_alternatives=2, profanity_filter=True,
            speech_contexts=self.HINTS)

        self.assertEqual(len(connection._requested), 1)
        req = connection._requested[0]
        self.assertEqual(len(req), 3)
        self.assertEqual(req['data'], request)
        self.assertEqual(req['method'], 'POST')
        self.assertEqual(req['path'], 'speech:recognize')

        alternative = SYNC_RECOGNIZE_RESPONSE['results'][0]['alternatives'][0]
        expected = Alternative.from_api_repr(alternative)
        self.assertEqual(len(response), 1)
        result = response[0]
        self.assertIsInstance(result, Result)
        self.assertEqual(len(result.alternatives), 1)
        alternative = result.alternatives[0]
        self.assertEqual(alternative.transcript, expected.transcript)
        self.assertEqual(alternative.confidence, expected.confidence)

    def test_sync_recognize_source_uri_without_optional_params_no_gax(self):
        from google.cloud import speech
        from google.cloud.speech.alternative import Alternative
        from google.cloud.speech.result import Result
        from tests.unit._fixtures import SYNC_RECOGNIZE_RESPONSE

        request = {
            'config': {
                'encoding': 'FLAC',
                'languageCode': 'en-US',
                'sampleRateHertz': 16000,
            },
            'audio': {
                'uri': self.AUDIO_SOURCE_URI,
            },
        }
        credentials = _make_credentials()
        client = self._make_one(credentials=credentials, _use_grpc=False)
        speech_api = client.speech_api
        connection = _Connection(SYNC_RECOGNIZE_RESPONSE)
        speech_api._connection = connection

        encoding = speech.Encoding.FLAC

        sample = client.sample(
            source_uri=self.AUDIO_SOURCE_URI, encoding=encoding,
            sample_rate_hertz=self.SAMPLE_RATE)

        response = [i for i in sample.recognize(language_code='en-US')]

        self.assertEqual(len(connection._requested), 1)
        req = connection._requested[0]
        self.assertEqual(len(req), 3)
        self.assertEqual(req['data'], request)
        self.assertEqual(req['method'], 'POST')
        self.assertEqual(req['path'], 'speech:recognize')

        expected = Alternative.from_api_repr(
            SYNC_RECOGNIZE_RESPONSE['results'][0]['alternatives'][0])
        self.assertEqual(len(response), 1)

        result = response[0]
        self.assertIsInstance(result, Result)
        self.assertEqual(len(result.alternatives), 1)

        alternative = result.alternatives[0]
        self.assertEqual(alternative.transcript, expected.transcript)
        self.assertEqual(alternative.confidence, expected.confidence)

    def test_sync_recognize_with_empty_results_no_gax(self):
        from google.cloud import speech
        from tests.unit._fixtures import SYNC_RECOGNIZE_EMPTY_RESPONSE

        credentials = _make_credentials()
        client = self._make_one(credentials=credentials, _use_grpc=False)
        speech_api = client.speech_api
        speech_api._connection = _Connection(SYNC_RECOGNIZE_EMPTY_RESPONSE)

        sample = client.sample(
            source_uri=self.AUDIO_SOURCE_URI, encoding=speech.Encoding.FLAC,
            sample_rate_hertz=self.SAMPLE_RATE)

        with self.assertRaises(ValueError):
            next(sample.recognize(language_code='en-US'))

    def test_sync_recognize_with_empty_results_gax(self):
        from google.cloud._testing import _Monkey

        from google.cloud import speech
        from google.cloud.speech import _gax

        credentials = _make_credentials()
        client = self._make_one(credentials=credentials, _use_grpc=True)
        client._credentials = credentials

        channel_args = []
        channel_obj = object()

        def make_channel(*args):
            channel_args.append(args)
            return channel_obj

        def speech_api(channel=None, **kwargs):
            return _MockGAPICSpeechAPI(
                response=_make_sync_response(), channel=channel, **kwargs)

        host = 'foo.apis.invalid'
        speech_api.SERVICE_ADDRESS = host

        with _Monkey(_gax, SpeechClient=speech_api,
                     make_secure_channel=make_channel):
            client._speech_api = _gax.GAPICSpeechAPI(client)

        low_level = client.speech_api._gapic_api
        self.assertIsInstance(low_level, _MockGAPICSpeechAPI)
        self.assertIs(low_level._channel, channel_obj)
        self.assertEqual(
            channel_args,
            [(credentials, _gax.DEFAULT_USER_AGENT, host)])

        sample = client.sample(
            source_uri=self.AUDIO_SOURCE_URI, encoding=speech.Encoding.FLAC,
            sample_rate_hertz=self.SAMPLE_RATE)

        with self.assertRaises(ValueError):
            next(sample.recognize(language_code='en-US'))

    def test_sync_recognize_with_gax(self):
        from google.cloud._testing import _Monkey

        from google.cloud import speech
        from google.cloud.speech import _gax

        creds = _make_credentials()
        client = self._make_one(credentials=creds, _use_grpc=True)
        client._credentials = creds

        alternatives = [{
            'transcript': 'testing 1 2 3',
            'confidence': 0.740234375,
        }, {
            'transcript': 'testing 4 5 6',
            'confidence': 0.6396484375,
        }]
        result = _make_result(alternatives)

        channel_args = []
        channel_obj = object()

        def make_channel(*args):
            channel_args.append(args)
            return channel_obj

        def speech_api(channel=None, **kwargs):
            return _MockGAPICSpeechAPI(
                response=_make_sync_response(result), channel=channel,
                **kwargs)

        host = 'foo.apis.invalid'
        speech_api.SERVICE_ADDRESS = host

        sample = client.sample(
            source_uri=self.AUDIO_SOURCE_URI, encoding=speech.Encoding.FLAC,
            sample_rate_hertz=self.SAMPLE_RATE)

        with _Monkey(_gax, SpeechClient=speech_api,
                     make_secure_channel=make_channel):
            client._speech_api = _gax.GAPICSpeechAPI(client)

        low_level = client.speech_api._gapic_api
        self.assertIsInstance(low_level, _MockGAPICSpeechAPI)
        self.assertIs(low_level._channel, channel_obj)
        self.assertEqual(
            channel_args, [(creds, _gax.DEFAULT_USER_AGENT, host)])

        results = [i for i in sample.recognize(language_code='en-US')]

        self.assertEqual(len(results), 1)
        result = results[0]
        self.assertEqual(len(results[0].alternatives), 2)
        self.assertEqual(
            result.transcript, result.alternatives[0].transcript,
            alternatives[0]['transcript'])
        self.assertEqual(
            result.confidence, result.alternatives[0].confidence,
            alternatives[0]['confidence'])
        self.assertEqual(
            result.alternatives[1].transcript, alternatives[1]['transcript'])
        self.assertEqual(
            result.alternatives[1].confidence, alternatives[1]['confidence'])

    def test_async_supported_encodings(self):
        from google.cloud import speech

        credentials = _make_credentials()
        client = self._make_one(credentials=credentials, _use_grpc=True)

        sample = client.sample(
            source_uri=self.AUDIO_SOURCE_URI, encoding=speech.Encoding.FLAC,
            sample_rate_hertz=self.SAMPLE_RATE)
        with self.assertRaises(ValueError):
            sample.recognize(language_code='en-US')

    def test_async_recognize_no_gax(self):
        from google.cloud import speech
        from google.cloud.speech.operation import Operation
        from tests.unit._fixtures import ASYNC_RECOGNIZE_RESPONSE

        RETURNED = ASYNC_RECOGNIZE_RESPONSE

        credentials = _make_credentials()
        client = self._make_one(credentials=credentials, _use_grpc=False)
        speech_api = client.speech_api
        speech_api._connection = _Connection(RETURNED)

        sample = client.sample(
            encoding=speech.Encoding.LINEAR16,
            sample_rate_hertz=self.SAMPLE_RATE,
            source_uri=self.AUDIO_SOURCE_URI,
        )
        operation = sample.long_running_recognize(language_code='en-US')
        self.assertIsInstance(operation, Operation)
        self.assertIs(operation.client, client)
        self.assertEqual(operation.caller_metadata, {
            'request_type': 'LongRunningRecognize',
        })
        self.assertFalse(operation.complete)
        self.assertIsNone(operation.metadata)

    def test_async_recognize_with_gax(self):
        from google.cloud._testing import _Monkey

        from google.cloud import speech
        from google.cloud.speech import _gax
        from google.cloud.speech.operation import Operation

        credentials = _make_credentials()
        client = self._make_one(credentials=credentials, _use_grpc=True)
        client._credentials = credentials

        channel_args = []
        channel_obj = object()

        def make_channel(*args):
            channel_args.append(args)
            return channel_obj

        sample = client.sample(
            encoding=speech.Encoding.LINEAR16,
            sample_rate_hertz=self.SAMPLE_RATE,
            source_uri=self.AUDIO_SOURCE_URI,
        )

        def speech_api(channel=None, **kwargs):
            return _MockGAPICSpeechAPI(channel=channel, **kwargs)

        host = 'foo.apis.invalid'
        speech_api.SERVICE_ADDRESS = host

        with _Monkey(_gax, SpeechClient=speech_api,
                     make_secure_channel=make_channel):
            api = client.speech_api

        low_level = api._gapic_api
        self.assertIsInstance(low_level, _MockGAPICSpeechAPI)
        self.assertIs(low_level._channel, channel_obj)
        expected = (credentials, _gax.DEFAULT_USER_AGENT,
                    low_level.SERVICE_ADDRESS)
        self.assertEqual(channel_args, [expected])

        operation = sample.long_running_recognize(language_code='en-US')
        self.assertIsInstance(operation, Operation)
        self.assertFalse(operation.complete)
        self.assertIsNone(operation.response)

    def test_streaming_depends_on_gax(self):
        from google.cloud import speech

        credentials = _make_credentials()
        client = self._make_one(credentials=credentials, _use_grpc=False)
        sample = client.sample(
            content=self.AUDIO_CONTENT, encoding=speech.Encoding.LINEAR16,
            sample_rate_hertz=self.SAMPLE_RATE)

        with self.assertRaises(EnvironmentError):
            list(sample.streaming_recognize(language_code='en-US'))

    def test_streaming_closed_stream(self):
        from io import BytesIO

        from google.cloud._testing import _Monkey

        from google.cloud.speech import _gax
        from google.cloud.speech.encoding import Encoding

        stream = BytesIO(b'Some audio data...')
        credentials = _make_credentials()
        client = self._make_one(credentials=credentials)
        client._credentials = credentials

        channel_args = []
        channel_obj = object()

        def make_channel(*args):
            channel_args.append(args)
            return channel_obj

        def speech_api(channel=None, **kwargs):
            return _MockGAPICSpeechAPI(channel=channel, **kwargs)

        host = 'foo.apis.invalid'
        speech_api.SERVICE_ADDRESS = host

        stream.close()
        self.assertTrue(stream.closed)

        sample = client.sample(
            stream=stream, encoding=Encoding.LINEAR16,
            sample_rate_hertz=self.SAMPLE_RATE)

        with _Monkey(_gax, SpeechClient=speech_api,
                     make_secure_channel=make_channel):
            client._speech_api = _gax.GAPICSpeechAPI(client)

        with self.assertRaises(ValueError):
            list(sample.streaming_recognize(language_code='en-US'))

    def test_stream_recognize_interim_results(self):
        from io import BytesIO

        from google.cloud._testing import _Monkey

        from google.cloud.speech import _gax
        from google.cloud.speech.encoding import Encoding
        from google.cloud.speech.result import StreamingSpeechResult

        stream = BytesIO(b'Some audio data...')
        credentials = _make_credentials()
        client = self._make_one(credentials=credentials)
        client._credentials = credentials

        alternatives = [{
            'transcript': 'testing streaming 1 2 3',
            'confidence': 0.5888671875,
        }, {
            'transcript': 'testing streaming 4 5 6',
            'confidence': 0.28125,
        }]
        first_response = _make_streaming_response(
            _make_streaming_result([], is_final=False, stability=0.314453125))
        second_response = _make_streaming_response(
            _make_streaming_result(
                alternatives, is_final=False, stability=0.28125))
        last_response = _make_streaming_response(
            _make_streaming_result(
                alternatives, is_final=True, stability=0.4375))
        responses = [first_response, second_response, last_response]

        channel_args = []
        channel_obj = object()

        def make_channel(*args):
            channel_args.append(args)
            return channel_obj

        def speech_api(channel=None, **kwargs):
            return _MockGAPICSpeechAPI(
                channel=channel, response=responses, **kwargs)

        host = 'foo.apis.invalid'
        speech_api.SERVICE_ADDRESS = host

        with _Monkey(_gax, SpeechClient=speech_api,
                     make_secure_channel=make_channel):
            client._speech_api = _gax.GAPICSpeechAPI(client)

        sample = client.sample(
            stream=stream, encoding=Encoding.LINEAR16,
            sample_rate_hertz=self.SAMPLE_RATE)

        results = list(sample.streaming_recognize(
            interim_results=True,
            language_code='en-US',
        ))

        self.assertEqual(len(results), 3)
        for result in results:
            self.assertIsInstance(result, StreamingSpeechResult)

        result = results[0]
        self.assertEqual(result.alternatives, [])
        self.assertFalse(result.is_final)
        self.assertEqual(result.stability, 0.314453125)

        result_two = results[1]
        self.assertEqual(result_two.stability, 0.28125)
        self.assertFalse(result_two.is_final)
        self.assertEqual(
            result_two.transcript, result_two.alternatives[0].transcript,
            alternatives[0]['transcript'])
        self.assertEqual(
            result_two.confidence, result_two.alternatives[0].confidence,
            alternatives[0]['confidence'])
        self.assertEqual(
            result_two.alternatives[1].transcript,
            alternatives[1]['transcript'])
        self.assertEqual(
            result_two.alternatives[1].confidence,
            alternatives[1]['confidence'])
        result_three = results[2]
        self.assertTrue(result_three.is_final)
        self.assertEqual(result_three.stability, 0.4375)
        self.assertEqual(
            result_three.transcript, result_three.alternatives[0].transcript,
            alternatives[0]['transcript'])
        self.assertEqual(
            result_three.confidence, result_three.alternatives[0].confidence,
            alternatives[0]['confidence'])

    def test_stream_recognize(self):
        from io import BytesIO

        from google.cloud._testing import _Monkey

        from google.cloud.speech import _gax
        from google.cloud.speech.encoding import Encoding

        stream = BytesIO(b'Some audio data...')
        credentials = _make_credentials()
        client = self._make_one(credentials=credentials)
        client._credentials = credentials

        alternatives = [{
            'transcript': 'testing streaming 1 2 3',
            'confidence': 0.4375,
        }, {
            'transcript': 'testing streaming 4 5 6',
            'confidence': 0.84375,
        }]

        first_response = _make_streaming_response(
            _make_streaming_result(alternatives=alternatives, is_final=False))
        last_response = _make_streaming_response(
            _make_streaming_result(alternatives=alternatives, is_final=True))
        responses = [first_response, last_response]

        channel_args = []
        channel_obj = object()

        def make_channel(*args):
            channel_args.append(args)
            return channel_obj

        def speech_api(channel=None, **kwargs):
            return _MockGAPICSpeechAPI(
                channel=channel, response=responses, **kwargs)

        host = 'foo.apis.invalid'
        speech_api.SERVICE_ADDRESS = host

        with _Monkey(_gax, SpeechClient=speech_api,
                     make_secure_channel=make_channel):
            client._speech_api = _gax.GAPICSpeechAPI(client)

        sample = client.sample(
            stream=stream, encoding=Encoding.LINEAR16,
            sample_rate_hertz=self.SAMPLE_RATE)

        results = list(sample.streaming_recognize(language_code='en-US'))
        self.assertEqual(len(results), 1)
        result = results[0]
        self.assertEqual(
            result.alternatives[0].transcript, alternatives[0]['transcript'])
        self.assertEqual(
            result.alternatives[0].confidence, alternatives[0]['confidence'])

    def test_stream_recognize_no_results(self):
        from io import BytesIO

        from google.cloud._testing import _Monkey

        from google.cloud.speech import _gax
        from google.cloud.speech.encoding import Encoding

        stream = BytesIO(b'Some audio data...')
        credentials = _make_credentials()
        client = self._make_one(credentials=credentials)
        client._credentials = credentials

        responses = [_make_streaming_response()]

        channel_args = []
        channel_obj = object()

        def make_channel(*args):
            channel_args.append(args)
            return channel_obj

        def speech_api(channel=None, **kwargs):
            return _MockGAPICSpeechAPI(
                channel=channel, response=responses, **kwargs)

        host = 'foo.apis.invalid'
        speech_api.SERVICE_ADDRESS = host

        with _Monkey(_gax, SpeechClient=speech_api,
                     make_secure_channel=make_channel):
            client._speech_api = _gax.GAPICSpeechAPI(client)

        sample = client.sample(
            stream=stream, encoding=Encoding.LINEAR16,
            sample_rate_hertz=self.SAMPLE_RATE)

        results = list(sample.streaming_recognize(language_code='en-US'))
        self.assertEqual(results, [])

    def test_speech_api_with_gax(self):
        from google.cloud._testing import _Monkey

        from google.cloud.speech import _gax

        creds = _make_credentials()
        client = self._make_one(credentials=creds, _use_grpc=True)
        client._credentials = creds

        channel_args = []
        channel_obj = object()

        def make_channel(*args):
            channel_args.append(args)
            return channel_obj

        def speech_api(channel=None, **kwargs):
            return _MockGAPICSpeechAPI(channel=channel, **kwargs)

        host = 'foo.apis.invalid'
        speech_api.SERVICE_ADDRESS = host

        with _Monkey(_gax, SpeechClient=speech_api,
                     make_secure_channel=make_channel):
            client._speech_api = _gax.GAPICSpeechAPI(client)

        low_level = client.speech_api._gapic_api
        self.assertIsInstance(low_level, _MockGAPICSpeechAPI)
        self.assertIs(low_level._channel, channel_obj)
        expected = (
            creds, _gax.DEFAULT_USER_AGENT, low_level.SERVICE_ADDRESS)
        self.assertEqual(channel_args, [expected])

    def test_speech_api_without_gax(self):
        from google.cloud._http import Connection
        from google.cloud.speech._http import HTTPSpeechAPI

        creds = _make_credentials()
        client = self._make_one(credentials=creds, _use_grpc=False)
        self.assertIsNone(client._speech_api)
        self.assertIsInstance(client.speech_api, HTTPSpeechAPI)
        self.assertIsInstance(client.speech_api._connection, Connection)

    def test_speech_api_preset(self):
        creds = _make_credentials()
        client = self._make_one(credentials=creds)
        fake_api = object()
        client._speech_api = fake_api

        self.assertIs(client.speech_api, fake_api)


class _MockGAPICSpeechAPI(object):
    _requests = None
    _response = None
    _results = None

    SERVICE_ADDRESS = 'foo.apis.invalid'

    def __init__(self, response=None, channel=None, **kwargs):
        self._response = response
        self._channel = channel
        self._kwargs = kwargs

    def long_running_recognize(self, config, audio):
        from google.gapic.longrunning.operations_client import OperationsClient
        from google.gax import _OperationFuture
        from google.longrunning.operations_pb2 import Operation
        from google.cloud.proto.speech.v1.cloud_speech_pb2 import (
            LongRunningRecognizeResponse)

        self.config = config
        self.audio = audio
        operations_client = mock.Mock(spec=OperationsClient)
        operation_future = _OperationFuture(
            Operation(), operations_client, LongRunningRecognizeResponse, {})
        return operation_future

    def recognize(self, config, audio):
        self.config = config
        self.audio = audio

        return self._response

    def streaming_recognize(self, requests):
        self._requests = requests
        for response in self._response:
            yield response


class _Connection(object):

    def __init__(self, *responses):
        self._responses = responses
        self._requested = []

    def api_request(self, **kw):
        self._requested.append(kw)
        response, self._responses = self._responses[0], self._responses[1:]
        return response
