# Copyright 2018, 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 logging
import threading
import time
import types as stdlib_types

import mock
import pytest
from six.moves import queue

from google.api_core import bidi
from google.api_core import exceptions
from google.cloud.pubsub_v1 import types
from google.cloud.pubsub_v1.gapic import subscriber_client_config
from google.cloud.pubsub_v1.subscriber import client
from google.cloud.pubsub_v1.subscriber import message
from google.cloud.pubsub_v1.subscriber import scheduler
from google.cloud.pubsub_v1.subscriber._protocol import dispatcher
from google.cloud.pubsub_v1.subscriber._protocol import heartbeater
from google.cloud.pubsub_v1.subscriber._protocol import leaser
from google.cloud.pubsub_v1.subscriber._protocol import requests
from google.cloud.pubsub_v1.subscriber._protocol import streaming_pull_manager
import grpc


@pytest.mark.parametrize(
    "exception,expected_cls",
    [
        (ValueError("meep"), ValueError),
        (
            mock.create_autospec(grpc.RpcError, instance=True),
            exceptions.GoogleAPICallError,
        ),
    ],
)
def test__maybe_wrap_exception(exception, expected_cls):
    assert isinstance(
        streaming_pull_manager._maybe_wrap_exception(exception), expected_cls
    )


def test__wrap_callback_errors_no_error():
    msg = mock.create_autospec(message.Message, instance=True)
    callback = mock.Mock()
    on_callback_error = mock.Mock()

    streaming_pull_manager._wrap_callback_errors(callback, on_callback_error, msg)

    callback.assert_called_once_with(msg)
    msg.nack.assert_not_called()
    on_callback_error.assert_not_called()


def test__wrap_callback_errors_error():
    callback_error = ValueError("meep")

    msg = mock.create_autospec(message.Message, instance=True)
    callback = mock.Mock(side_effect=callback_error)
    on_callback_error = mock.Mock()

    streaming_pull_manager._wrap_callback_errors(callback, on_callback_error, msg)

    msg.nack.assert_called_once()
    on_callback_error.assert_called_once_with(callback_error)


def test_constructor_and_default_state():
    manager = streaming_pull_manager.StreamingPullManager(
        mock.sentinel.client, mock.sentinel.subscription
    )

    # Public state
    assert manager.is_active is False
    assert manager.flow_control == types.FlowControl()
    assert manager.dispatcher is None
    assert manager.leaser is None
    assert manager.ack_histogram is not None
    assert manager.ack_deadline == 10
    assert manager.load == 0

    # Private state
    assert manager._client == mock.sentinel.client
    assert manager._subscription == mock.sentinel.subscription
    assert manager._scheduler is not None


def test_constructor_with_options():
    manager = streaming_pull_manager.StreamingPullManager(
        mock.sentinel.client,
        mock.sentinel.subscription,
        flow_control=mock.sentinel.flow_control,
        scheduler=mock.sentinel.scheduler,
    )

    assert manager.flow_control == mock.sentinel.flow_control
    assert manager._scheduler == mock.sentinel.scheduler


def make_manager(**kwargs):
    client_ = mock.create_autospec(client.Client, instance=True)
    scheduler_ = mock.create_autospec(scheduler.Scheduler, instance=True)
    return streaming_pull_manager.StreamingPullManager(
        client_, "subscription-name", scheduler=scheduler_, **kwargs
    )


def fake_leaser_add(leaser, init_msg_count=0, init_bytes=0):
    """Add a simplified fake add() method to a leaser instance.

    The fake add() method actually increases the leaser's internal message count
    by one for each message, and the total bytes by 10 for each message (hardcoded,
    regardless of the actual message size).
    """

    def fake_add(self, items):
        self.message_count += len(items)
        self.bytes += len(items) * 10

    leaser.message_count = init_msg_count
    leaser.bytes = init_bytes
    leaser.add = stdlib_types.MethodType(fake_add, leaser)


def test_ack_deadline():
    manager = make_manager()
    assert manager.ack_deadline == 10
    manager.ack_histogram.add(20)
    assert manager.ack_deadline == 20
    manager.ack_histogram.add(10)
    assert manager.ack_deadline == 20


def test_maybe_pause_consumer_wo_consumer_set():
    manager = make_manager(
        flow_control=types.FlowControl(max_messages=10, max_bytes=1000)
    )
    manager.maybe_pause_consumer()  # no raise
    # Ensure load > 1
    _leaser = manager._leaser = mock.create_autospec(leaser.Leaser)
    _leaser.message_count = 100
    _leaser.bytes = 10000
    manager.maybe_pause_consumer()  # no raise


def test_lease_load_and_pause():
    manager = make_manager(
        flow_control=types.FlowControl(max_messages=10, max_bytes=1000)
    )
    manager._leaser = leaser.Leaser(manager)
    manager._consumer = mock.create_autospec(bidi.BackgroundConsumer, instance=True)
    manager._consumer.is_paused = False

    # This should mean that our messages count is at 10%, and our bytes
    # are at 15%; load should return the higher (0.15), and shouldn't cause
    # the consumer to pause.
    manager.leaser.add([requests.LeaseRequest(ack_id="one", byte_size=150)])
    assert manager.load == 0.15
    manager.maybe_pause_consumer()
    manager._consumer.pause.assert_not_called()

    # After this message is added, the messages should be higher at 20%
    # (versus 16% for bytes).
    manager.leaser.add([requests.LeaseRequest(ack_id="two", byte_size=10)])
    assert manager.load == 0.2

    # Returning a number above 100% is fine, and it should cause this to pause.
    manager.leaser.add([requests.LeaseRequest(ack_id="three", byte_size=1000)])
    assert manager.load == 1.16
    manager.maybe_pause_consumer()
    manager._consumer.pause.assert_called_once()


def test_drop_and_resume():
    manager = make_manager(
        flow_control=types.FlowControl(max_messages=10, max_bytes=1000)
    )
    manager._leaser = leaser.Leaser(manager)
    manager._consumer = mock.create_autospec(bidi.BackgroundConsumer, instance=True)
    manager._consumer.is_paused = True

    # Add several messages until we're over the load threshold.
    manager.leaser.add(
        [
            requests.LeaseRequest(ack_id="one", byte_size=750),
            requests.LeaseRequest(ack_id="two", byte_size=250),
        ]
    )

    assert manager.load == 1.0

    # Trying to resume now should have no effect as we're over the threshold.
    manager.maybe_resume_consumer()
    manager._consumer.resume.assert_not_called()

    # Drop the 200 byte message, which should put us under the resume
    # threshold.
    manager.leaser.remove([requests.DropRequest(ack_id="two", byte_size=250)])
    manager.maybe_resume_consumer()
    manager._consumer.resume.assert_called_once()


def test_resume_not_paused():
    manager = make_manager()
    manager._consumer = mock.create_autospec(bidi.BackgroundConsumer, instance=True)
    manager._consumer.is_paused = False

    # Resuming should have no effect is the consumer is not actually paused.
    manager.maybe_resume_consumer()
    manager._consumer.resume.assert_not_called()


def test_maybe_resume_consumer_wo_consumer_set():
    manager = make_manager(
        flow_control=types.FlowControl(max_messages=10, max_bytes=1000)
    )
    manager.maybe_resume_consumer()  # no raise


def test__maybe_release_messages_on_overload():
    manager = make_manager(
        flow_control=types.FlowControl(max_messages=10, max_bytes=1000)
    )
    # Ensure load is exactly 1.0 (to verify that >= condition is used)
    _leaser = manager._leaser = mock.create_autospec(leaser.Leaser)
    _leaser.message_count = 10
    _leaser.bytes = 1000

    msg = mock.create_autospec(message.Message, instance=True, ack_id="ack", size=11)
    manager._messages_on_hold.put(msg)

    manager._maybe_release_messages()

    assert manager._messages_on_hold.qsize() == 1
    manager._leaser.add.assert_not_called()
    manager._scheduler.schedule.assert_not_called()


def test__maybe_release_messages_below_overload():
    manager = make_manager(
        flow_control=types.FlowControl(max_messages=10, max_bytes=1000)
    )
    manager._callback = mock.sentinel.callback

    # init leaser message count to 8 to leave room for 2 more messages
    _leaser = manager._leaser = mock.create_autospec(leaser.Leaser)
    fake_leaser_add(_leaser, init_msg_count=8, init_bytes=200)
    _leaser.add = mock.Mock(wraps=_leaser.add)  # to spy on calls

    messages = [
        mock.create_autospec(message.Message, instance=True, ack_id="ack_foo", size=11),
        mock.create_autospec(message.Message, instance=True, ack_id="ack_bar", size=22),
        mock.create_autospec(message.Message, instance=True, ack_id="ack_baz", size=33),
    ]
    for msg in messages:
        manager._messages_on_hold.put(msg)

    # the actual call of MUT
    manager._maybe_release_messages()

    assert manager._messages_on_hold.qsize() == 1
    msg = manager._messages_on_hold.get_nowait()
    assert msg.ack_id == "ack_baz"

    assert len(_leaser.add.mock_calls) == 2
    expected_calls = [
        mock.call([requests.LeaseRequest(ack_id="ack_foo", byte_size=11)]),
        mock.call([requests.LeaseRequest(ack_id="ack_bar", byte_size=22)]),
    ]
    _leaser.add.assert_has_calls(expected_calls)

    schedule_calls = manager._scheduler.schedule.mock_calls
    assert len(schedule_calls) == 2
    for _, call_args, _ in schedule_calls:
        assert call_args[0] == mock.sentinel.callback
        assert isinstance(call_args[1], message.Message)
        assert call_args[1].ack_id in ("ack_foo", "ack_bar")


def test_send_unary():
    manager = make_manager()
    manager._UNARY_REQUESTS = True

    manager.send(
        types.StreamingPullRequest(
            ack_ids=["ack_id1", "ack_id2"],
            modify_deadline_ack_ids=["ack_id3", "ack_id4", "ack_id5"],
            modify_deadline_seconds=[10, 20, 20],
        )
    )

    manager._client.acknowledge.assert_called_once_with(
        subscription=manager._subscription, ack_ids=["ack_id1", "ack_id2"]
    )

    manager._client.modify_ack_deadline.assert_has_calls(
        [
            mock.call(
                subscription=manager._subscription,
                ack_ids=["ack_id3"],
                ack_deadline_seconds=10,
            ),
            mock.call(
                subscription=manager._subscription,
                ack_ids=["ack_id4", "ack_id5"],
                ack_deadline_seconds=20,
            ),
        ],
        any_order=True,
    )


def test_send_unary_empty():
    manager = make_manager()
    manager._UNARY_REQUESTS = True

    manager.send(types.StreamingPullRequest())

    manager._client.acknowledge.assert_not_called()
    manager._client.modify_ack_deadline.assert_not_called()


def test_send_unary_api_call_error(caplog):
    caplog.set_level(logging.DEBUG)

    manager = make_manager()
    manager._UNARY_REQUESTS = True

    error = exceptions.GoogleAPICallError("The front fell off")
    manager._client.acknowledge.side_effect = error

    manager.send(types.StreamingPullRequest(ack_ids=["ack_id1", "ack_id2"]))

    assert "The front fell off" in caplog.text


def test_send_unary_retry_error(caplog):
    caplog.set_level(logging.DEBUG)

    manager, _, _, _, _, _ = make_running_manager()
    manager._UNARY_REQUESTS = True

    error = exceptions.RetryError(
        "Too long a transient error", cause=Exception("Out of time!")
    )
    manager._client.acknowledge.side_effect = error

    with pytest.raises(exceptions.RetryError):
        manager.send(types.StreamingPullRequest(ack_ids=["ack_id1", "ack_id2"]))

    assert "RetryError while sending unary RPC" in caplog.text
    assert "signaled streaming pull manager shutdown" in caplog.text


def test_send_streaming():
    manager = make_manager()
    manager._UNARY_REQUESTS = False
    manager._rpc = mock.create_autospec(bidi.BidiRpc, instance=True)

    manager.send(mock.sentinel.request)

    manager._rpc.send.assert_called_once_with(mock.sentinel.request)


def test_heartbeat():
    manager = make_manager()
    manager._rpc = mock.create_autospec(bidi.BidiRpc, instance=True)
    manager._rpc.is_active = True

    manager.heartbeat()

    manager._rpc.send.assert_called_once_with(types.StreamingPullRequest())


def test_heartbeat_inactive():
    manager = make_manager()
    manager._rpc = mock.create_autospec(bidi.BidiRpc, instance=True)
    manager._rpc.is_active = False

    manager.heartbeat()

    manager._rpc.send.assert_not_called()


@mock.patch("google.api_core.bidi.ResumableBidiRpc", autospec=True)
@mock.patch("google.api_core.bidi.BackgroundConsumer", autospec=True)
@mock.patch("google.cloud.pubsub_v1.subscriber._protocol.leaser.Leaser", autospec=True)
@mock.patch(
    "google.cloud.pubsub_v1.subscriber._protocol.dispatcher.Dispatcher", autospec=True
)
@mock.patch(
    "google.cloud.pubsub_v1.subscriber._protocol.heartbeater.Heartbeater", autospec=True
)
def test_open(heartbeater, dispatcher, leaser, background_consumer, resumable_bidi_rpc):
    manager = make_manager()

    manager.open(mock.sentinel.callback, mock.sentinel.on_callback_error)

    heartbeater.assert_called_once_with(manager)
    heartbeater.return_value.start.assert_called_once()
    assert manager._heartbeater == heartbeater.return_value

    dispatcher.assert_called_once_with(manager, manager._scheduler.queue)
    dispatcher.return_value.start.assert_called_once()
    assert manager._dispatcher == dispatcher.return_value

    leaser.assert_called_once_with(manager)
    leaser.return_value.start.assert_called_once()
    assert manager.leaser == leaser.return_value

    background_consumer.assert_called_once_with(manager._rpc, manager._on_response)
    background_consumer.return_value.start.assert_called_once()
    assert manager._consumer == background_consumer.return_value

    resumable_bidi_rpc.assert_called_once_with(
        start_rpc=manager._client.api.streaming_pull,
        initial_request=manager._get_initial_request,
        should_recover=manager._should_recover,
        throttle_reopen=True,
    )
    resumable_bidi_rpc.return_value.add_done_callback.assert_called_once_with(
        manager._on_rpc_done
    )
    assert manager._rpc == resumable_bidi_rpc.return_value

    manager._consumer.is_active = True
    assert manager.is_active is True


def test_open_already_active():
    manager = make_manager()
    manager._consumer = mock.create_autospec(bidi.BackgroundConsumer, instance=True)
    manager._consumer.is_active = True

    with pytest.raises(ValueError, match="already open"):
        manager.open(mock.sentinel.callback, mock.sentinel.on_callback_error)


def test_open_has_been_closed():
    manager = make_manager()
    manager._closed = True

    with pytest.raises(ValueError, match="closed"):
        manager.open(mock.sentinel.callback, mock.sentinel.on_callback_error)


def make_running_manager():
    manager = make_manager()
    manager._consumer = mock.create_autospec(bidi.BackgroundConsumer, instance=True)
    manager._consumer.is_active = True
    manager._dispatcher = mock.create_autospec(dispatcher.Dispatcher, instance=True)
    manager._leaser = mock.create_autospec(leaser.Leaser, instance=True)
    manager._heartbeater = mock.create_autospec(heartbeater.Heartbeater, instance=True)

    return (
        manager,
        manager._consumer,
        manager._dispatcher,
        manager._leaser,
        manager._heartbeater,
        manager._scheduler,
    )


def test_close():
    manager, consumer, dispatcher, leaser, heartbeater, scheduler = (
        make_running_manager()
    )

    manager.close()

    consumer.stop.assert_called_once()
    leaser.stop.assert_called_once()
    dispatcher.stop.assert_called_once()
    heartbeater.stop.assert_called_once()
    scheduler.shutdown.assert_called_once()

    assert manager.is_active is False


def test_close_inactive_consumer():
    manager, consumer, dispatcher, leaser, heartbeater, scheduler = (
        make_running_manager()
    )
    consumer.is_active = False

    manager.close()

    consumer.stop.assert_not_called()
    leaser.stop.assert_called_once()
    dispatcher.stop.assert_called_once()
    heartbeater.stop.assert_called_once()
    scheduler.shutdown.assert_called_once()


def test_close_idempotent():
    manager, _, _, _, _, scheduler = make_running_manager()

    manager.close()
    manager.close()

    assert scheduler.shutdown.call_count == 1


class FakeDispatcher(object):
    def __init__(self, manager, error_callback):
        self._manager = manager
        self._error_callback = error_callback
        self._thread = None
        self._stop = False

    def start(self):
        self._thread = threading.Thread(target=self._do_work)
        self._thread.daemon = True
        self._thread.start()

    def stop(self):
        self._stop = True
        self._thread.join()
        self._thread = None

    def _do_work(self):
        while not self._stop:
            try:
                self._manager.leaser.add([mock.Mock()])
            except Exception as exc:
                self._error_callback(exc)
            time.sleep(0.1)

        # also try to interact with the leaser after the stop flag has been set
        try:
            self._manager.leaser.remove([mock.Mock()])
        except Exception as exc:
            self._error_callback(exc)


def test_close_no_dispatcher_error():
    manager, _, _, _, _, _ = make_running_manager()
    error_callback = mock.Mock(name="error_callback")
    dispatcher = FakeDispatcher(manager=manager, error_callback=error_callback)
    manager._dispatcher = dispatcher
    dispatcher.start()

    manager.close()

    error_callback.assert_not_called()


def test_close_callbacks():
    manager, _, _, _, _, _ = make_running_manager()

    callback = mock.Mock()

    manager.add_close_callback(callback)
    manager.close(reason="meep")

    callback.assert_called_once_with(manager, "meep")


def test__get_initial_request():
    manager = make_manager()
    manager._leaser = mock.create_autospec(leaser.Leaser, instance=True)
    manager._leaser.ack_ids = ["1", "2"]

    initial_request = manager._get_initial_request()

    assert isinstance(initial_request, types.StreamingPullRequest)
    assert initial_request.subscription == "subscription-name"
    assert initial_request.stream_ack_deadline_seconds == 10
    assert initial_request.modify_deadline_ack_ids == ["1", "2"]
    assert initial_request.modify_deadline_seconds == [10, 10]


def test__get_initial_request_wo_leaser():
    manager = make_manager()
    manager._leaser = None

    initial_request = manager._get_initial_request()

    assert isinstance(initial_request, types.StreamingPullRequest)
    assert initial_request.subscription == "subscription-name"
    assert initial_request.stream_ack_deadline_seconds == 10
    assert initial_request.modify_deadline_ack_ids == []
    assert initial_request.modify_deadline_seconds == []


def test__on_response_no_leaser_overload():
    manager, _, dispatcher, leaser, _, scheduler = make_running_manager()
    manager._callback = mock.sentinel.callback

    # Set up the messages.
    response = types.StreamingPullResponse(
        received_messages=[
            types.ReceivedMessage(
                ack_id="fack", message=types.PubsubMessage(data=b"foo", message_id="1")
            ),
            types.ReceivedMessage(
                ack_id="back", message=types.PubsubMessage(data=b"bar", message_id="2")
            ),
        ]
    )

    # adjust message bookkeeping in leaser
    fake_leaser_add(leaser, init_msg_count=0, init_bytes=0)

    # Actually run the method and prove that modack and schedule
    # are called in the expected way.
    manager._on_response(response)

    dispatcher.modify_ack_deadline.assert_called_once_with(
        [requests.ModAckRequest("fack", 10), requests.ModAckRequest("back", 10)]
    )

    schedule_calls = scheduler.schedule.mock_calls
    assert len(schedule_calls) == 2
    for call in schedule_calls:
        assert call[1][0] == mock.sentinel.callback
        assert isinstance(call[1][1], message.Message)

    # the leaser load limit not hit, no messages had to be put on hold
    assert manager._messages_on_hold.qsize() == 0


def test__on_response_with_leaser_overload():
    manager, _, dispatcher, leaser, _, scheduler = make_running_manager()
    manager._callback = mock.sentinel.callback

    # Set up the messages.
    response = types.StreamingPullResponse(
        received_messages=[
            types.ReceivedMessage(
                ack_id="fack", message=types.PubsubMessage(data=b"foo", message_id="1")
            ),
            types.ReceivedMessage(
                ack_id="back", message=types.PubsubMessage(data=b"bar", message_id="2")
            ),
            types.ReceivedMessage(
                ack_id="zack", message=types.PubsubMessage(data=b"baz", message_id="3")
            ),
        ]
    )

    # Adjust message bookkeeping in leaser. Pick 99 messages, which is just below
    # the default FlowControl.max_messages limit.
    fake_leaser_add(leaser, init_msg_count=99, init_bytes=990)

    # Actually run the method and prove that modack and schedule
    # are called in the expected way.
    manager._on_response(response)

    dispatcher.modify_ack_deadline.assert_called_once_with(
        [
            requests.ModAckRequest("fack", 10),
            requests.ModAckRequest("back", 10),
            requests.ModAckRequest("zack", 10),
        ]
    )

    # one message should be scheduled, the leaser capacity allows for it
    schedule_calls = scheduler.schedule.mock_calls
    assert len(schedule_calls) == 1
    call_args = schedule_calls[0][1]
    assert call_args[0] == mock.sentinel.callback
    assert isinstance(call_args[1], message.Message)
    assert call_args[1].message_id == "1"

    # the rest of the messages should have been put on hold
    assert manager._messages_on_hold.qsize() == 2
    while True:
        try:
            msg = manager._messages_on_hold.get_nowait()
        except queue.Empty:
            break
        else:
            assert isinstance(msg, message.Message)
            assert msg.message_id in ("2", "3")


def test_retryable_stream_errors():
    # Make sure the config matches our hard-coded tuple of exceptions.
    interfaces = subscriber_client_config.config["interfaces"]
    retry_codes = interfaces["google.pubsub.v1.Subscriber"]["retry_codes"]
    idempotent = retry_codes["idempotent"]

    status_codes = tuple(getattr(grpc.StatusCode, name, None) for name in idempotent)
    expected = tuple(
        exceptions.exception_class_for_grpc_status(status_code)
        for status_code in status_codes
    )
    assert set(expected).issubset(set(streaming_pull_manager._RETRYABLE_STREAM_ERRORS))


def test__should_recover_true():
    manager = make_manager()

    details = "UNAVAILABLE. Service taking nap."
    exc = exceptions.ServiceUnavailable(details)

    assert manager._should_recover(exc) is True


def test__should_recover_false():
    manager = make_manager()

    exc = TypeError("wahhhhhh")

    assert manager._should_recover(exc) is False


@mock.patch("threading.Thread", autospec=True)
def test__on_rpc_done(thread):
    manager = make_manager()

    manager._on_rpc_done(mock.sentinel.error)

    thread.assert_called_once_with(
        name=mock.ANY, target=manager.close, kwargs={"reason": mock.sentinel.error}
    )
