# Copyright 2016 gRPC authors.
#
# 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.
"""Defines a number of module-scope gRPC scenarios to test clean exit."""

import argparse
import threading
import time

import grpc

from tests.unit.framework.common import test_constants

WAIT_TIME = 1000

REQUEST = b'request'

UNSTARTED_SERVER = 'unstarted_server'
RUNNING_SERVER = 'running_server'
POLL_CONNECTIVITY_NO_SERVER = 'poll_connectivity_no_server'
POLL_CONNECTIVITY = 'poll_connectivity'
IN_FLIGHT_UNARY_UNARY_CALL = 'in_flight_unary_unary_call'
IN_FLIGHT_UNARY_STREAM_CALL = 'in_flight_unary_stream_call'
IN_FLIGHT_STREAM_UNARY_CALL = 'in_flight_stream_unary_call'
IN_FLIGHT_STREAM_STREAM_CALL = 'in_flight_stream_stream_call'
IN_FLIGHT_PARTIAL_UNARY_STREAM_CALL = 'in_flight_partial_unary_stream_call'
IN_FLIGHT_PARTIAL_STREAM_UNARY_CALL = 'in_flight_partial_stream_unary_call'
IN_FLIGHT_PARTIAL_STREAM_STREAM_CALL = 'in_flight_partial_stream_stream_call'

UNARY_UNARY = b'/test/UnaryUnary'
UNARY_STREAM = b'/test/UnaryStream'
STREAM_UNARY = b'/test/StreamUnary'
STREAM_STREAM = b'/test/StreamStream'
PARTIAL_UNARY_STREAM = b'/test/PartialUnaryStream'
PARTIAL_STREAM_UNARY = b'/test/PartialStreamUnary'
PARTIAL_STREAM_STREAM = b'/test/PartialStreamStream'

TEST_TO_METHOD = {
    IN_FLIGHT_UNARY_UNARY_CALL: UNARY_UNARY,
    IN_FLIGHT_UNARY_STREAM_CALL: UNARY_STREAM,
    IN_FLIGHT_STREAM_UNARY_CALL: STREAM_UNARY,
    IN_FLIGHT_STREAM_STREAM_CALL: STREAM_STREAM,
    IN_FLIGHT_PARTIAL_UNARY_STREAM_CALL: PARTIAL_UNARY_STREAM,
    IN_FLIGHT_PARTIAL_STREAM_UNARY_CALL: PARTIAL_STREAM_UNARY,
    IN_FLIGHT_PARTIAL_STREAM_STREAM_CALL: PARTIAL_STREAM_STREAM,
}


def hang_unary_unary(request, servicer_context):
    time.sleep(WAIT_TIME)


def hang_unary_stream(request, servicer_context):
    time.sleep(WAIT_TIME)


def hang_partial_unary_stream(request, servicer_context):
    for _ in range(test_constants.STREAM_LENGTH // 2):
        yield request
    time.sleep(WAIT_TIME)


def hang_stream_unary(request_iterator, servicer_context):
    time.sleep(WAIT_TIME)


def hang_partial_stream_unary(request_iterator, servicer_context):
    for _ in range(test_constants.STREAM_LENGTH // 2):
        next(request_iterator)
    time.sleep(WAIT_TIME)


def hang_stream_stream(request_iterator, servicer_context):
    time.sleep(WAIT_TIME)


def hang_partial_stream_stream(request_iterator, servicer_context):
    for _ in range(test_constants.STREAM_LENGTH // 2):
        yield next(request_iterator)
    time.sleep(WAIT_TIME)


class MethodHandler(grpc.RpcMethodHandler):

    def __init__(self, request_streaming, response_streaming, partial_hang):
        self.request_streaming = request_streaming
        self.response_streaming = response_streaming
        self.request_deserializer = None
        self.response_serializer = None
        self.unary_unary = None
        self.unary_stream = None
        self.stream_unary = None
        self.stream_stream = None
        if self.request_streaming and self.response_streaming:
            if partial_hang:
                self.stream_stream = hang_partial_stream_stream
            else:
                self.stream_stream = hang_stream_stream
        elif self.request_streaming:
            if partial_hang:
                self.stream_unary = hang_partial_stream_unary
            else:
                self.stream_unary = hang_stream_unary
        elif self.response_streaming:
            if partial_hang:
                self.unary_stream = hang_partial_unary_stream
            else:
                self.unary_stream = hang_unary_stream
        else:
            self.unary_unary = hang_unary_unary


class GenericHandler(grpc.GenericRpcHandler):

    def service(self, handler_call_details):
        if handler_call_details.method == UNARY_UNARY:
            return MethodHandler(False, False, False)
        elif handler_call_details.method == UNARY_STREAM:
            return MethodHandler(False, True, False)
        elif handler_call_details.method == STREAM_UNARY:
            return MethodHandler(True, False, False)
        elif handler_call_details.method == STREAM_STREAM:
            return MethodHandler(True, True, False)
        elif handler_call_details.method == PARTIAL_UNARY_STREAM:
            return MethodHandler(False, True, True)
        elif handler_call_details.method == PARTIAL_STREAM_UNARY:
            return MethodHandler(True, False, True)
        elif handler_call_details.method == PARTIAL_STREAM_STREAM:
            return MethodHandler(True, True, True)
        else:
            return None


# Traditional executors will not exit until all their
# current jobs complete.  Because we submit jobs that will
# never finish, we don't want to block exit on these jobs.
class DaemonPool(object):

    def submit(self, fn, *args, **kwargs):
        thread = threading.Thread(target=fn, args=args, kwargs=kwargs)
        thread.daemon = True
        thread.start()

    def shutdown(self, wait=True):
        pass


def infinite_request_iterator():
    while True:
        yield REQUEST


if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('scenario', type=str)
    parser.add_argument(
        '--wait_for_interrupt', dest='wait_for_interrupt', action='store_true')
    args = parser.parse_args()

    if args.scenario == UNSTARTED_SERVER:
        server = grpc.server(DaemonPool())
        if args.wait_for_interrupt:
            time.sleep(WAIT_TIME)
    elif args.scenario == RUNNING_SERVER:
        server = grpc.server(DaemonPool())
        port = server.add_insecure_port('[::]:0')
        server.start()
        if args.wait_for_interrupt:
            time.sleep(WAIT_TIME)
    elif args.scenario == POLL_CONNECTIVITY_NO_SERVER:
        channel = grpc.insecure_channel('localhost:12345')

        def connectivity_callback(connectivity):
            pass

        channel.subscribe(connectivity_callback, try_to_connect=True)
        if args.wait_for_interrupt:
            time.sleep(WAIT_TIME)
    elif args.scenario == POLL_CONNECTIVITY:
        server = grpc.server(DaemonPool())
        port = server.add_insecure_port('[::]:0')
        server.start()
        channel = grpc.insecure_channel('localhost:%d' % port)

        def connectivity_callback(connectivity):
            pass

        channel.subscribe(connectivity_callback, try_to_connect=True)
        if args.wait_for_interrupt:
            time.sleep(WAIT_TIME)

    else:
        handler = GenericHandler()
        server = grpc.server(DaemonPool())
        port = server.add_insecure_port('[::]:0')
        server.add_generic_rpc_handlers((handler,))
        server.start()
        channel = grpc.insecure_channel('localhost:%d' % port)

        method = TEST_TO_METHOD[args.scenario]

        if args.scenario == IN_FLIGHT_UNARY_UNARY_CALL:
            multi_callable = channel.unary_unary(method)
            future = multi_callable.future(REQUEST)
            result, call = multi_callable.with_call(REQUEST)
        elif (args.scenario == IN_FLIGHT_UNARY_STREAM_CALL or
              args.scenario == IN_FLIGHT_PARTIAL_UNARY_STREAM_CALL):
            multi_callable = channel.unary_stream(method)
            response_iterator = multi_callable(REQUEST)
            for response in response_iterator:
                pass
        elif (args.scenario == IN_FLIGHT_STREAM_UNARY_CALL or
              args.scenario == IN_FLIGHT_PARTIAL_STREAM_UNARY_CALL):
            multi_callable = channel.stream_unary(method)
            future = multi_callable.future(infinite_request_iterator())
            result, call = multi_callable.with_call(
                iter([REQUEST] * test_constants.STREAM_LENGTH))
        elif (args.scenario == IN_FLIGHT_STREAM_STREAM_CALL or
              args.scenario == IN_FLIGHT_PARTIAL_STREAM_STREAM_CALL):
            multi_callable = channel.stream_stream(method)
            response_iterator = multi_callable(infinite_request_iterator())
            for response in response_iterator:
                pass
