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import argparse
import contextlib
import distutils.spawn
import errno
import itertools
import os
import pkg_resources
import shutil
import subprocess
import sys
import tempfile
import threading
import time
import unittest

from six import moves

from grpc.beta import implementations
from grpc.framework.foundation import future
from grpc.framework.interfaces.face import face
from tests.unit.framework.common import test_constants

# Identifiers of entities we expect to find in the generated module.
SERVICER_IDENTIFIER = 'BetaTestServiceServicer'
STUB_IDENTIFIER = 'BetaTestServiceStub'
SERVER_FACTORY_IDENTIFIER = 'beta_create_TestService_server'
STUB_FACTORY_IDENTIFIER = 'beta_create_TestService_stub'


class _ServicerMethods(object):

  def __init__(self, test_pb2):
    self._condition = threading.Condition()
    self._paused = False
    self._fail = False
    self._test_pb2 = test_pb2

  @contextlib.contextmanager
  def pause(self):  # pylint: disable=invalid-name
    with self._condition:
      self._paused = True
    yield
    with self._condition:
      self._paused = False
      self._condition.notify_all()

  @contextlib.contextmanager
  def fail(self):  # pylint: disable=invalid-name
    with self._condition:
      self._fail = True
    yield
    with self._condition:
      self._fail = False

  def _control(self):  # pylint: disable=invalid-name
    with self._condition:
      if self._fail:
        raise ValueError()
      while self._paused:
        self._condition.wait()

  def UnaryCall(self, request, unused_rpc_context):
    response = self._test_pb2.SimpleResponse()
    response.payload.payload_type = self._test_pb2.COMPRESSABLE
    response.payload.payload_compressable = 'a' * request.response_size
    self._control()
    return response

  def StreamingOutputCall(self, request, unused_rpc_context):
    for parameter in request.response_parameters:
      response = self._test_pb2.StreamingOutputCallResponse()
      response.payload.payload_type = self._test_pb2.COMPRESSABLE
      response.payload.payload_compressable = 'a' * parameter.size
      self._control()
      yield response

  def StreamingInputCall(self, request_iter, unused_rpc_context):
    response = self._test_pb2.StreamingInputCallResponse()
    aggregated_payload_size = 0
    for request in request_iter:
      aggregated_payload_size += len(request.payload.payload_compressable)
    response.aggregated_payload_size = aggregated_payload_size
    self._control()
    return response

  def FullDuplexCall(self, request_iter, unused_rpc_context):
    for request in request_iter:
      for parameter in request.response_parameters:
        response = self._test_pb2.StreamingOutputCallResponse()
        response.payload.payload_type = self._test_pb2.COMPRESSABLE
        response.payload.payload_compressable = 'a' * parameter.size
        self._control()
        yield response

  def HalfDuplexCall(self, request_iter, unused_rpc_context):
    responses = []
    for request in request_iter:
      for parameter in request.response_parameters:
        response = self._test_pb2.StreamingOutputCallResponse()
        response.payload.payload_type = self._test_pb2.COMPRESSABLE
        response.payload.payload_compressable = 'a' * parameter.size
        self._control()
        responses.append(response)
    for response in responses:
      yield response


@contextlib.contextmanager
def _CreateService(test_pb2):
  """Provides a servicer backend and a stub.

  The servicer is just the implementation of the actual servicer passed to the
  face player of the python RPC implementation; the two are detached.

  Args:
    test_pb2: The test_pb2 module generated by this test.

  Yields:
    A (servicer_methods, stub) pair where servicer_methods is the back-end of
      the service bound to the stub and and stub is the stub on which to invoke
      RPCs.
  """
  servicer_methods = _ServicerMethods(test_pb2)

  class Servicer(getattr(test_pb2, SERVICER_IDENTIFIER)):

    def UnaryCall(self, request, context):
      return servicer_methods.UnaryCall(request, context)

    def StreamingOutputCall(self, request, context):
      return servicer_methods.StreamingOutputCall(request, context)

    def StreamingInputCall(self, request_iter, context):
      return servicer_methods.StreamingInputCall(request_iter, context)

    def FullDuplexCall(self, request_iter, context):
      return servicer_methods.FullDuplexCall(request_iter, context)

    def HalfDuplexCall(self, request_iter, context):
      return servicer_methods.HalfDuplexCall(request_iter, context)

  servicer = Servicer()
  server = getattr(test_pb2, SERVER_FACTORY_IDENTIFIER)(servicer)
  port = server.add_insecure_port('[::]:0')
  server.start()
  channel = implementations.insecure_channel('localhost', port)
  stub = getattr(test_pb2, STUB_FACTORY_IDENTIFIER)(channel)
  yield servicer_methods, stub
  server.stop(0)


def _streaming_input_request_iterator(test_pb2):
  for _ in range(3):
    request = test_pb2.StreamingInputCallRequest()
    request.payload.payload_type = test_pb2.COMPRESSABLE
    request.payload.payload_compressable = 'a'
    yield request


def _streaming_output_request(test_pb2):
  request = test_pb2.StreamingOutputCallRequest()
  sizes = [1, 2, 3]
  request.response_parameters.add(size=sizes[0], interval_us=0)
  request.response_parameters.add(size=sizes[1], interval_us=0)
  request.response_parameters.add(size=sizes[2], interval_us=0)
  return request


def _full_duplex_request_iterator(test_pb2):
  request = test_pb2.StreamingOutputCallRequest()
  request.response_parameters.add(size=1, interval_us=0)
  yield request
  request = test_pb2.StreamingOutputCallRequest()
  request.response_parameters.add(size=2, interval_us=0)
  request.response_parameters.add(size=3, interval_us=0)
  yield request


class PythonPluginTest(unittest.TestCase):
  """Test case for the gRPC Python protoc-plugin.

  While reading these tests, remember that the futures API
  (`stub.method.future()`) only gives futures for the *response-unary*
  methods and does not exist for response-streaming methods.
  """

  def setUp(self):
    # Assume that the appropriate protoc and grpc_python_plugins are on the
    # path.
    protoc_command = 'protoc'
    protoc_plugin_filename = distutils.spawn.find_executable(
        'grpc_python_plugin')
    test_proto_filename = pkg_resources.resource_filename(
        'tests.protoc_plugin', 'protoc_plugin_test.proto')
    if not os.path.isfile(protoc_command):
      # Assume that if we haven't built protoc that it's on the system.
      protoc_command = 'protoc'

    # Ensure that the output directory exists.
    self.outdir = tempfile.mkdtemp()

    # Invoke protoc with the plugin.
    cmd = [
        protoc_command,
        '--plugin=protoc-gen-python-grpc=%s' % protoc_plugin_filename,
        '-I .',
        '--python_out=%s' % self.outdir,
        '--python-grpc_out=%s' % self.outdir,
        os.path.basename(test_proto_filename),
    ]
    subprocess.check_call(' '.join(cmd), shell=True, env=os.environ,
                          cwd=os.path.dirname(test_proto_filename))
    sys.path.insert(0, self.outdir)

  def tearDown(self):
    try:
      shutil.rmtree(self.outdir)
    except OSError as exc:
      if exc.errno != errno.ENOENT:
        raise
    sys.path.remove(self.outdir)

  def testImportAttributes(self):
    # check that we can access the generated module and its members.
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    self.assertIsNotNone(getattr(test_pb2, SERVICER_IDENTIFIER, None))
    self.assertIsNotNone(getattr(test_pb2, STUB_IDENTIFIER, None))
    self.assertIsNotNone(getattr(test_pb2, SERVER_FACTORY_IDENTIFIER, None))
    self.assertIsNotNone(getattr(test_pb2, STUB_FACTORY_IDENTIFIER, None))

  def testUpDown(self):
    import protoc_plugin_test_pb2 as test_pb2
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (servicer, stub):
      request = test_pb2.SimpleRequest(response_size=13)

  def testUnaryCall(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      request = test_pb2.SimpleRequest(response_size=13)
      response = stub.UnaryCall(request, test_constants.LONG_TIMEOUT)
    expected_response = methods.UnaryCall(request, 'not a real context!')
    self.assertEqual(expected_response, response)

  def testUnaryCallFuture(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request = test_pb2.SimpleRequest(response_size=13)
    with _CreateService(test_pb2) as (methods, stub):
      # Check that the call does not block waiting for the server to respond.
      with methods.pause():
        response_future = stub.UnaryCall.future(
            request, test_constants.LONG_TIMEOUT)
      response = response_future.result()
    expected_response = methods.UnaryCall(request, 'not a real RpcContext!')
    self.assertEqual(expected_response, response)

  def testUnaryCallFutureExpired(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      request = test_pb2.SimpleRequest(response_size=13)
      with methods.pause():
        response_future = stub.UnaryCall.future(
            request, test_constants.SHORT_TIMEOUT)
        with self.assertRaises(face.ExpirationError):
          response_future.result()

  def testUnaryCallFutureCancelled(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request = test_pb2.SimpleRequest(response_size=13)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.pause():
        response_future = stub.UnaryCall.future(request, 1)
        response_future.cancel()
        self.assertTrue(response_future.cancelled())

  def testUnaryCallFutureFailed(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request = test_pb2.SimpleRequest(response_size=13)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.fail():
        response_future = stub.UnaryCall.future(
            request, test_constants.LONG_TIMEOUT)
        self.assertIsNotNone(response_future.exception())

  def testStreamingOutputCall(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request = _streaming_output_request(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      responses = stub.StreamingOutputCall(
          request, test_constants.LONG_TIMEOUT)
      expected_responses = methods.StreamingOutputCall(
          request, 'not a real RpcContext!')
      for expected_response, response in moves.zip_longest(
          expected_responses, responses):
        self.assertEqual(expected_response, response)

  def testStreamingOutputCallExpired(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request = _streaming_output_request(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.pause():
        responses = stub.StreamingOutputCall(
            request, test_constants.SHORT_TIMEOUT)
        with self.assertRaises(face.ExpirationError):
          list(responses)

  def testStreamingOutputCallCancelled(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request = _streaming_output_request(test_pb2)
    with _CreateService(test_pb2) as (unused_methods, stub):
      responses = stub.StreamingOutputCall(
          request, test_constants.LONG_TIMEOUT)
      next(responses)
      responses.cancel()
      with self.assertRaises(face.CancellationError):
        next(responses)

  def testStreamingOutputCallFailed(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request = _streaming_output_request(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.fail():
        responses = stub.StreamingOutputCall(request, 1)
        self.assertIsNotNone(responses)
        with self.assertRaises(face.RemoteError):
          next(responses)

  def testStreamingInputCall(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      response = stub.StreamingInputCall(
          _streaming_input_request_iterator(test_pb2),
          test_constants.LONG_TIMEOUT)
    expected_response = methods.StreamingInputCall(
        _streaming_input_request_iterator(test_pb2), 'not a real RpcContext!')
    self.assertEqual(expected_response, response)

  def testStreamingInputCallFuture(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.pause():
        response_future = stub.StreamingInputCall.future(
            _streaming_input_request_iterator(test_pb2),
            test_constants.LONG_TIMEOUT)
      response = response_future.result()
    expected_response = methods.StreamingInputCall(
        _streaming_input_request_iterator(test_pb2), 'not a real RpcContext!')
    self.assertEqual(expected_response, response)

  def testStreamingInputCallFutureExpired(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.pause():
        response_future = stub.StreamingInputCall.future(
            _streaming_input_request_iterator(test_pb2),
            test_constants.SHORT_TIMEOUT)
        with self.assertRaises(face.ExpirationError):
          response_future.result()
        self.assertIsInstance(
            response_future.exception(), face.ExpirationError)

  def testStreamingInputCallFutureCancelled(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.pause():
        response_future = stub.StreamingInputCall.future(
            _streaming_input_request_iterator(test_pb2),
            test_constants.LONG_TIMEOUT)
        response_future.cancel()
        self.assertTrue(response_future.cancelled())
      with self.assertRaises(future.CancelledError):
        response_future.result()

  def testStreamingInputCallFutureFailed(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.fail():
        response_future = stub.StreamingInputCall.future(
            _streaming_input_request_iterator(test_pb2),
            test_constants.LONG_TIMEOUT)
        self.assertIsNotNone(response_future.exception())

  def testFullDuplexCall(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      responses = stub.FullDuplexCall(
          _full_duplex_request_iterator(test_pb2), test_constants.LONG_TIMEOUT)
      expected_responses = methods.FullDuplexCall(
          _full_duplex_request_iterator(test_pb2), 'not a real RpcContext!')
      for expected_response, response in moves.zip_longest(
          expected_responses, responses):
        self.assertEqual(expected_response, response)

  def testFullDuplexCallExpired(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request_iterator = _full_duplex_request_iterator(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.pause():
        responses = stub.FullDuplexCall(
            request_iterator, test_constants.SHORT_TIMEOUT)
        with self.assertRaises(face.ExpirationError):
          list(responses)

  def testFullDuplexCallCancelled(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      request_iterator = _full_duplex_request_iterator(test_pb2)
      responses = stub.FullDuplexCall(
          request_iterator, test_constants.LONG_TIMEOUT)
      next(responses)
      responses.cancel()
      with self.assertRaises(face.CancellationError):
        next(responses)

  def testFullDuplexCallFailed(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    request_iterator = _full_duplex_request_iterator(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      with methods.fail():
        responses = stub.FullDuplexCall(
            request_iterator, test_constants.LONG_TIMEOUT)
        self.assertIsNotNone(responses)
        with self.assertRaises(face.RemoteError):
          next(responses)

  def testHalfDuplexCall(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    with _CreateService(test_pb2) as (methods, stub):
      def half_duplex_request_iterator():
        request = test_pb2.StreamingOutputCallRequest()
        request.response_parameters.add(size=1, interval_us=0)
        yield request
        request = test_pb2.StreamingOutputCallRequest()
        request.response_parameters.add(size=2, interval_us=0)
        request.response_parameters.add(size=3, interval_us=0)
        yield request
      responses = stub.HalfDuplexCall(
          half_duplex_request_iterator(), test_constants.LONG_TIMEOUT)
      expected_responses = methods.HalfDuplexCall(
          half_duplex_request_iterator(), 'not a real RpcContext!')
      for check in moves.zip_longest(expected_responses, responses):
        expected_response, response = check
        self.assertEqual(expected_response, response)

  def testHalfDuplexCallWedged(self):
    import protoc_plugin_test_pb2 as test_pb2  # pylint: disable=g-import-not-at-top
    moves.reload_module(test_pb2)
    condition = threading.Condition()
    wait_cell = [False]
    @contextlib.contextmanager
    def wait():  # pylint: disable=invalid-name
      # Where's Python 3's 'nonlocal' statement when you need it?
      with condition:
        wait_cell[0] = True
      yield
      with condition:
        wait_cell[0] = False
        condition.notify_all()
    def half_duplex_request_iterator():
      request = test_pb2.StreamingOutputCallRequest()
      request.response_parameters.add(size=1, interval_us=0)
      yield request
      with condition:
        while wait_cell[0]:
          condition.wait()
    with _CreateService(test_pb2) as (methods, stub):
      with wait():
        responses = stub.HalfDuplexCall(
            half_duplex_request_iterator(), test_constants.SHORT_TIMEOUT)
        # half-duplex waits for the client to send all info
        with self.assertRaises(face.ExpirationError):
          next(responses)


if __name__ == '__main__':
  os.chdir(os.path.dirname(sys.argv[0]))
  unittest.main(verbosity=2)
