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"""Coverage across the Face layer's generic-to-dynamic range for invocation."""

import abc

import six

from grpc.framework.common import cardinality

_CARDINALITY_TO_GENERIC_BLOCKING_BEHAVIOR = {
    cardinality.Cardinality.UNARY_UNARY: 'blocking_unary_unary',
    cardinality.Cardinality.UNARY_STREAM: 'inline_unary_stream',
    cardinality.Cardinality.STREAM_UNARY: 'blocking_stream_unary',
    cardinality.Cardinality.STREAM_STREAM: 'inline_stream_stream',
}

_CARDINALITY_TO_GENERIC_FUTURE_BEHAVIOR = {
    cardinality.Cardinality.UNARY_UNARY: 'future_unary_unary',
    cardinality.Cardinality.UNARY_STREAM: 'inline_unary_stream',
    cardinality.Cardinality.STREAM_UNARY: 'future_stream_unary',
    cardinality.Cardinality.STREAM_STREAM: 'inline_stream_stream',
}

_CARDINALITY_TO_GENERIC_EVENT_BEHAVIOR = {
    cardinality.Cardinality.UNARY_UNARY: 'event_unary_unary',
    cardinality.Cardinality.UNARY_STREAM: 'event_unary_stream',
    cardinality.Cardinality.STREAM_UNARY: 'event_stream_unary',
    cardinality.Cardinality.STREAM_STREAM: 'event_stream_stream',
}

_CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE = {
    cardinality.Cardinality.UNARY_UNARY: 'unary_unary',
    cardinality.Cardinality.UNARY_STREAM: 'unary_stream',
    cardinality.Cardinality.STREAM_UNARY: 'stream_unary',
    cardinality.Cardinality.STREAM_STREAM: 'stream_stream',
}


class Invoker(six.with_metaclass(abc.ABCMeta)):
  """A type used to invoke test RPCs."""

  @abc.abstractmethod
  def blocking(self, group, name):
    """Invokes an RPC with blocking control flow."""
    raise NotImplementedError()

  @abc.abstractmethod
  def future(self, group, name):
    """Invokes an RPC with future control flow."""
    raise NotImplementedError()

  @abc.abstractmethod
  def event(self, group, name):
    """Invokes an RPC with event control flow."""
    raise NotImplementedError()


class InvokerConstructor(six.with_metaclass(abc.ABCMeta)):
  """A type used to create Invokers."""

  @abc.abstractmethod
  def name(self):
    """Specifies the name of the Invoker constructed by this object."""
    raise NotImplementedError()

  @abc.abstractmethod
  def construct_invoker(self, generic_stub, dynamic_stubs, methods):
    """Constructs an Invoker for the given stubs and methods."""
    raise NotImplementedError()


class _GenericInvoker(Invoker):

  def __init__(self, generic_stub, methods):
    self._stub = generic_stub
    self._methods = methods

  def _behavior(self, group, name, cardinality_to_generic_method):
    method_cardinality = self._methods[group, name].cardinality()
    behavior = getattr(
        self._stub, cardinality_to_generic_method[method_cardinality])
    return lambda *args, **kwargs: behavior(group, name, *args, **kwargs)

  def blocking(self, group, name):
    return self._behavior(
        group, name, _CARDINALITY_TO_GENERIC_BLOCKING_BEHAVIOR)

  def future(self, group, name):
    return self._behavior(group, name, _CARDINALITY_TO_GENERIC_FUTURE_BEHAVIOR)

  def event(self, group, name):
    return self._behavior(group, name, _CARDINALITY_TO_GENERIC_EVENT_BEHAVIOR)


class _GenericInvokerConstructor(InvokerConstructor):

  def name(self):
    return 'GenericInvoker'

  def construct_invoker(self, generic_stub, dynamic_stub, methods):
    return _GenericInvoker(generic_stub, methods)


class _MultiCallableInvoker(Invoker):

  def __init__(self, generic_stub, methods):
    self._stub = generic_stub
    self._methods = methods

  def _multi_callable(self, group, name):
    method_cardinality = self._methods[group, name].cardinality()
    behavior = getattr(
        self._stub,
        _CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE[method_cardinality])
    return behavior(group, name)

  def blocking(self, group, name):
    return self._multi_callable(group, name)

  def future(self, group, name):
    method_cardinality = self._methods[group, name].cardinality()
    behavior = getattr(
        self._stub,
        _CARDINALITY_TO_MULTI_CALLABLE_ATTRIBUTE[method_cardinality])
    if method_cardinality in (
        cardinality.Cardinality.UNARY_UNARY,
        cardinality.Cardinality.STREAM_UNARY):
      return behavior(group, name).future
    else:
      return behavior(group, name)

  def event(self, group, name):
    return self._multi_callable(group, name).event


class _MultiCallableInvokerConstructor(InvokerConstructor):

  def name(self):
    return 'MultiCallableInvoker'

  def construct_invoker(self, generic_stub, dynamic_stub, methods):
    return _MultiCallableInvoker(generic_stub, methods)


class _DynamicInvoker(Invoker):

  def __init__(self, dynamic_stubs, methods):
    self._stubs = dynamic_stubs
    self._methods = methods

  def blocking(self, group, name):
    return getattr(self._stubs[group], name)

  def future(self, group, name):
    if self._methods[group, name].cardinality() in (
        cardinality.Cardinality.UNARY_UNARY,
        cardinality.Cardinality.STREAM_UNARY):
      return getattr(self._stubs[group], name).future
    else:
      return getattr(self._stubs[group], name)

  def event(self, group, name):
    return getattr(self._stubs[group], name).event


class _DynamicInvokerConstructor(InvokerConstructor):

  def name(self):
    return 'DynamicInvoker'

  def construct_invoker(self, generic_stub, dynamic_stubs, methods):
    return _DynamicInvoker(dynamic_stubs, methods)


def invoker_constructors():
  """Creates a sequence of InvokerConstructors to use in tests of RPCs.

  Returns:
    A sequence of InvokerConstructors.
  """
  return (
      _GenericInvokerConstructor(),
      _MultiCallableInvokerConstructor(),
      _DynamicInvokerConstructor(),
  )