# Copyright 2015 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.

cimport cpython

import time


cdef class Server:

  def __cinit__(self, ChannelArgs arguments):
    grpc_init()
    cdef grpc_channel_args *c_arguments = NULL
    self.references = []
    self.registered_completion_queues = []
    if len(arguments) > 0:
      c_arguments = &arguments.c_args
      self.references.append(arguments)
    with nogil:
      self.c_server = grpc_server_create(c_arguments, NULL)
    self.is_started = False
    self.is_shutting_down = False
    self.is_shutdown = False

  def request_call(
      self, CompletionQueue call_queue not None,
      CompletionQueue server_queue not None, tag):
    if not self.is_started or self.is_shutting_down:
      raise ValueError("server must be started and not shutting down")
    if server_queue not in self.registered_completion_queues:
      raise ValueError("server_queue must be a registered completion queue")
    cdef grpc_call_error result
    cdef OperationTag operation_tag = OperationTag(tag)
    operation_tag.operation_call = Call()
    operation_tag.request_call_details = CallDetails()
    operation_tag.request_metadata = MetadataArray()
    operation_tag.references.extend([self, call_queue, server_queue])
    operation_tag.is_new_request = True
    operation_tag.batch_operations = Operations([])
    cpython.Py_INCREF(operation_tag)
    with nogil:
      result = grpc_server_request_call(
          self.c_server, &operation_tag.operation_call.c_call,
          &operation_tag.request_call_details.c_details,
          &operation_tag.request_metadata.c_metadata_array,
          call_queue.c_completion_queue, server_queue.c_completion_queue,
          <cpython.PyObject *>operation_tag)
    return result

  def register_completion_queue(
      self, CompletionQueue queue not None):
    if self.is_started:
      raise ValueError("cannot register completion queues after start")
    with nogil:
      grpc_server_register_completion_queue(
          self.c_server, queue.c_completion_queue, NULL)
    self.registered_completion_queues.append(queue)

  def start(self):
    if self.is_started:
      raise ValueError("the server has already started")
    self.backup_shutdown_queue = CompletionQueue(shutdown_cq=True)
    self.register_completion_queue(self.backup_shutdown_queue)
    self.is_started = True
    with nogil:
      grpc_server_start(self.c_server)
    # Ensure the core has gotten a chance to do the start-up work
    self.backup_shutdown_queue.poll(Timespec(None))

  def add_http2_port(self, bytes address,
                     ServerCredentials server_credentials=None):
    address = str_to_bytes(address)
    self.references.append(address)
    cdef int result
    cdef char *address_c_string = address
    if server_credentials is not None:
      self.references.append(server_credentials)
      with nogil:
        result = grpc_server_add_secure_http2_port(
            self.c_server, address_c_string, server_credentials.c_credentials)
    else:
      with nogil:
        result = grpc_server_add_insecure_http2_port(self.c_server,
                                                     address_c_string)
    return result

  cdef _c_shutdown(self, CompletionQueue queue, tag):
    self.is_shutting_down = True
    operation_tag = OperationTag(tag)
    operation_tag.shutting_down_server = self
    cpython.Py_INCREF(operation_tag)
    with nogil:
      grpc_server_shutdown_and_notify(
          self.c_server, queue.c_completion_queue,
          <cpython.PyObject *>operation_tag)

  def shutdown(self, CompletionQueue queue not None, tag):
    cdef OperationTag operation_tag
    if queue.is_shutting_down:
      raise ValueError("queue must be live")
    elif not self.is_started:
      raise ValueError("the server hasn't started yet")
    elif self.is_shutting_down:
      return
    elif queue not in self.registered_completion_queues:
      raise ValueError("expected registered completion queue")
    else:
      self._c_shutdown(queue, tag)

  cdef notify_shutdown_complete(self):
    # called only by a completion queue on receiving our shutdown operation tag
    self.is_shutdown = True

  def cancel_all_calls(self):
    if not self.is_shutting_down:
      raise RuntimeError("the server must be shutting down to cancel all calls")
    elif self.is_shutdown:
      return
    else:
      with nogil:
        grpc_server_cancel_all_calls(self.c_server)

  def __dealloc__(self):
    if self.c_server != NULL:
      if not self.is_started:
        pass
      elif self.is_shutdown:
        pass
      elif not self.is_shutting_down:
        # the user didn't call shutdown - use our backup queue
        self._c_shutdown(self.backup_shutdown_queue, None)
        # and now we wait
        while not self.is_shutdown:
          self.backup_shutdown_queue.poll()
      else:
        # We're in the process of shutting down, but have not shutdown; can't do
        # much but repeatedly release the GIL and wait
        while not self.is_shutdown:
          time.sleep(0)
      grpc_server_destroy(self.c_server)
    grpc_shutdown()
