#   Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
#
# 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.
# pylint: disable=doc-string-missing
from concurrent import futures
import grpc
import logging
import json
import socket
import contextlib
from contextlib import closing
import multiprocessing
import yaml

from .proto import pipeline_service_pb2_grpc, pipeline_service_pb2
from . import operator
from . import dag
from . import util
from . import channel

_LOGGER = logging.getLogger(__name__)


class PipelineServicer(pipeline_service_pb2_grpc.PipelineServiceServicer):
    """
    Pipeline Servicer entrance.
    """

    def __init__(self, name, response_op, dag_conf, worker_idx=-1):
        super(PipelineServicer, self).__init__()
        self._name = name

        # init dag executor
        self._dag_executor = dag.DAGExecutor(response_op, dag_conf, worker_idx)
        self._dag_executor.start()
        _LOGGER.info("[PipelineServicer] succ init")

    def inference(self, request, context):
        _LOGGER.info("(log_id={}) inference request name:{} self.name:{}".
                     format(request.logid, request.name, self._name))
        if request.name != "" and request.name != self._name:
            _LOGGER.error("(log_id={}) name dismatch error. request.name:{},"
                          "server.name={}".format(request.logid, request.name,
                                                  self._name))
            resp = pipeline_service_pb2.Response()
            resp.err_no = channel.ChannelDataErrcode.NO_SERVICE.value
            resp.err_msg = "Failed to inference: Service name error."
            resp.result = ""
            return resp
        resp = self._dag_executor.call(request)
        return resp


@contextlib.contextmanager
def _reserve_port(port):
    """
    Find and reserve a port for all subprocesses to use.
    """
    sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
    if sock.getsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT) == 0:
        raise RuntimeError("Failed to set SO_REUSEPORT.")
    sock.bind(('', port))
    try:
        yield sock.getsockname()[1]
    finally:
        sock.close()


class PipelineServer(object):
    """
    Pipeline Server : grpc gateway + grpc server.
    """

    def __init__(self, name=None):
        self._name = name  # for grpc-gateway path
        self._rpc_port = None
        self._worker_num = None
        self._response_op = None
        self._proxy_server = None

    def _grpc_gateway(self, grpc_port, http_port):
        """
        Running a gateway server, linking libproxy_server.so

        Args:
            grpc_port: GRPC port
            http_port: HTTP port

        Returns:
            None
        """
        import os
        from ctypes import cdll
        from . import gateway
        lib_path = os.path.join(
            os.path.dirname(gateway.__file__), "libproxy_server.so")
        proxy_server = cdll.LoadLibrary(lib_path)
        proxy_server.run_proxy_server(grpc_port, http_port)

    def _run_grpc_gateway(self, grpc_port, http_port):
        """
        Starting the GRPC gateway in a new process. Exposing one 
        available HTTP port outside, and reflecting the data to RPC port.

        Args:
            grpc_port: GRPC port
            http_port: HTTP port

        Returns:
            None
        """
        if http_port <= 0:
            _LOGGER.info("Ignore grpc_gateway configuration.")
            return
        if not util.AvailablePortGenerator.port_is_available(http_port):
            raise SystemExit("Failed to run grpc-gateway: prot {} "
                             "is already used".format(http_port))
        if self._proxy_server is not None:
            raise RuntimeError("Proxy server has been started.")
        self._proxy_server = multiprocessing.Process(
            target=self._grpc_gateway, args=(
                grpc_port,
                http_port, ))
        self._proxy_server.daemon = True
        self._proxy_server.start()

    def set_response_op(self, response_op):
        """
        Set the response OP.

        Args:
            response_op: ResponseOp or its subclass object

        Returns:
            None
        """
        if not isinstance(response_op, operator.ResponseOp):
            raise Exception("Failed to set response_op: response_op "
                            "must be ResponseOp type.")
        if len(response_op.get_input_ops()) != 1:
            raise Exception("Failed to set response_op: response_op "
                            "can only have one previous op.")
        self._response_op = response_op
        self._used_op, _ = dag.DAG.get_use_ops(self._response_op)

    def prepare_server(self, yml_file=None, yml_dict=None):
        """
        Reading configures from the yml file(config.yaml), and launching
        local services.

        Args:
            yml_file: Reading configures from yaml files
            yml_dict: Reading configures from yaml dict.
   
        Returns:
            None 
        """
        conf = ServerYamlConfChecker.load_server_yaml_conf(
            yml_file=yml_file, yml_dict=yml_dict)

        self._rpc_port = conf.get("rpc_port")
        self._http_port = conf.get("http_port")
        if self._rpc_port is None:
            if self._http_port is None:
                raise SystemExit("Failed to prepare_server: rpc_port or "
                                 "http_port can not be None.")
            else:
                # http mode: generate rpc_port
                if not util.AvailablePortGenerator.port_is_available(
                        self._http_port):
                    raise SystemExit("Failed to prepare_server: http_port({}) "
                                     "is already used".format(self._http_port))
                self._rpc_port = util.GetAvailablePortGenerator().next()
        else:
            if not util.AvailablePortGenerator.port_is_available(
                    self._rpc_port):
                raise SystemExit("Failed to prepare_server: prot {} "
                                 "is already used".format(self._rpc_port))
            if self._http_port is None:
                # rpc mode
                pass
            else:
                # http mode
                if not util.AvailablePortGenerator.port_is_available(
                        self._http_port):
                    raise SystemExit("Failed to prepare_server: http_port({}) "
                                     "is already used".format(self._http_port))

        self._worker_num = conf["worker_num"]
        self._build_dag_each_worker = conf["build_dag_each_worker"]
        self._init_ops(conf["op"])

        _LOGGER.info("============= PIPELINE SERVER =============")
        _LOGGER.info("\n{}".format(
            json.dumps(
                conf, indent=4, separators=(',', ':'))))
        if self._build_dag_each_worker is True:
            _LOGGER.warning(
                "(Make sure that install grpcio whl with --no-binary flag: "
                "pip install grpcio --no-binary grpcio)")
        _LOGGER.info("-------------------------------------------")

        self._conf = conf
        self._start_local_rpc_service()

    def _init_ops(self, op_conf):
        """
        Initializing all OPs from dicetory.

        Args:
            op_conf: the op configures in yaml dict.

        Returns:
            None.
        """
        default_conf = {
            "concurrency": 1,
            "timeout": -1,
            "retry": 1,
            "batch_size": 1,
            "auto_batching_timeout": -1,
            "local_service_conf": {
                "workdir": "",
                "thread_num": 2,
                "devices": "",
                "mem_optim": True,
                "ir_optim": False,
            },
        }
        for op in self._used_op:
            if not isinstance(op, operator.RequestOp) and not isinstance(
                    op, operator.ResponseOp):
                conf = op_conf.get(op.name, default_conf)
                op.init_from_dict(conf)

    def _start_local_rpc_service(self):
        # only brpc now
        if self._conf["dag"]["client_type"] != "brpc":
            _LOGGER.warning("Local service version must be brpc type now.")
        for op in self._used_op:
            if not isinstance(op, operator.RequestOp):
                op.launch_local_rpc_service()

    def run_server(self):
        """
        If _build_dag_each_worker is True, Starting _worker_num processes and 
        running one GRPC server in each process. Otherwise, Staring one GRPC
        server.

        Args:
            None

        Returns:
            None
        """
        if self._build_dag_each_worker:
            with _reserve_port(self._rpc_port) as port:
                bind_address = 'localhost:{}'.format(port)
                workers = []
                for i in range(self._worker_num):
                    worker = multiprocessing.Process(
                        target=self._run_server_func,
                        args=(bind_address, self._response_op, self._conf, i))
                    worker.start()
                    workers.append(worker)
                self._run_grpc_gateway(
                    grpc_port=self._rpc_port,
                    http_port=self._http_port)  # start grpc_gateway
                for worker in workers:
                    worker.join()
        else:
            server = grpc.server(
                futures.ThreadPoolExecutor(max_workers=self._worker_num),
                options=[('grpc.max_send_message_length', 256 * 1024 * 1024),
                         ('grpc.max_receive_message_length', 256 * 1024 * 1024)
                         ])
            pipeline_service_pb2_grpc.add_PipelineServiceServicer_to_server(
                PipelineServicer(self._name, self._response_op, self._conf),
                server)
            server.add_insecure_port('[::]:{}'.format(self._rpc_port))
            server.start()
            self._run_grpc_gateway(
                grpc_port=self._rpc_port,
                http_port=self._http_port)  # start grpc_gateway
            server.wait_for_termination()

    def _run_server_func(self, bind_address, response_op, dag_conf, worker_idx):
        """
        Running one GRPC server with PipelineServicer.

        Args:
            bind_address: binding IP/Port
            response_op: ResponseOp or its subclass object
            dag_conf: DAG config
            worker_idx: Process index.
        """
        options = [('grpc.so_reuseport', 1),
                   ('grpc.max_send_message_length', 256 * 1024 * 1024),
                   ('grpc.max_send_message_length', 256 * 1024 * 1024)]
        server = grpc.server(
            futures.ThreadPoolExecutor(
                max_workers=1, ), options=options)
        pipeline_service_pb2_grpc.add_PipelineServiceServicer_to_server(
            PipelineServicer(self._name, response_op, dag_conf, worker_idx),
            server)
        server.add_insecure_port(bind_address)
        server.start()
        server.wait_for_termination()


class ServerYamlConfChecker(object):
    """
    Checking validities of server yaml files.
    """

    def __init__(self):
        pass

    @staticmethod
    def load_server_yaml_conf(yml_file=None, yml_dict=None):
        if yml_file is not None and yml_dict is not None:
            raise SystemExit("Failed to prepare_server: only one of yml_file"
                             " or yml_dict can be selected as the parameter.")
        if yml_file is not None:
            with open(yml_file, encoding='utf-8') as f:
                conf = yaml.load(f.read())
        elif yml_dict is not None:
            conf = yml_dict
        else:
            raise SystemExit("Failed to prepare_server: yml_file or yml_dict"
                             " can not be None.")
        ServerYamlConfChecker.check_server_conf(conf)
        ServerYamlConfChecker.check_dag_conf(conf["dag"])
        ServerYamlConfChecker.check_tracer_conf(conf["dag"]["tracer"])
        for op_name in conf["op"]:
            ServerYamlConfChecker.check_op_conf(conf["op"][op_name])
            ServerYamlConfChecker.check_local_service_conf(conf["op"][op_name][
                "local_service_conf"])
        return conf

    @staticmethod
    def check_conf(conf, default_conf, conf_type, conf_qualification):
        ServerYamlConfChecker.fill_with_default_conf(conf, default_conf)
        ServerYamlConfChecker.check_conf_type(conf, conf_type)
        ServerYamlConfChecker.check_conf_qualification(conf, conf_qualification)

    @staticmethod
    def check_server_conf(conf):
        default_conf = {
            # "rpc_port": 9292,
            "worker_num": 1,
            "build_dag_each_worker": False,
            #"http_port": 0,
            "dag": {},
            "op": {},
        }

        conf_type = {
            "rpc_port": int,
            "http_port": int,
            "worker_num": int,
            "build_dag_each_worker": bool,
            "grpc_gateway_port": int,
        }

        conf_qualification = {
            "rpc_port": [(">=", 1024), ("<=", 65535)],
            "http_port": [(">=", 1024), ("<=", 65535)],
            "worker_num": (">=", 1),
        }

        ServerYamlConfChecker.check_conf(conf, default_conf, conf_type,
                                         conf_qualification)

    @staticmethod
    def check_local_service_conf(conf):
        default_conf = {
            "workdir": "",
            "thread_num": 2,
            "devices": "",
            "mem_optim": True,
            "ir_optim": False,
        }
        conf_type = {
            "model_config": str,
            "workdir": str,
            "thread_num": int,
            "devices": str,
            "mem_optim": bool,
            "ir_optim": bool,
        }
        conf_qualification = {"thread_num": (">=", 1), }
        ServerYamlConfChecker.check_conf(conf, default_conf, conf_type,
                                         conf_qualification)

    @staticmethod
    def check_op_conf(conf):
        default_conf = {
            "concurrency": 1,
            "timeout": -1,
            "retry": 1,
            "batch_size": 1,
            "auto_batching_timeout": -1,
            "local_service_conf": {},
        }
        conf_type = {
            "server_endpoints": list,
            "fetch_list": list,
            "client_config": str,
            "concurrency": int,
            "timeout": int,
            "retry": int,
            "batch_size": int,
            "auto_batching_timeout": int,
        }
        conf_qualification = {
            "concurrency": (">=", 1),
            "retry": (">=", 1),
            "batch_size": (">=", 1),
        }
        ServerYamlConfChecker.check_conf(conf, default_conf, conf_type,
                                         conf_qualification)

    @staticmethod
    def check_tracer_conf(conf):
        default_conf = {"interval_s": -1, }

        conf_type = {"interval_s": int, }

        conf_qualification = {}

        ServerYamlConfChecker.check_conf(conf, default_conf, conf_type,
                                         conf_qualification)

    @staticmethod
    def check_dag_conf(conf):
        default_conf = {
            "retry": 1,
            "client_type": "brpc",
            "use_profile": False,
            "channel_size": 0,
            "is_thread_op": True,
            "tracer": {},
        }

        conf_type = {
            "retry": int,
            "client_type": str,
            "use_profile": bool,
            "channel_size": int,
            "is_thread_op": bool,
        }

        conf_qualification = {
            "retry": (">=", 1),
            "client_type": ("in", ["brpc", "grpc"]),
            "channel_size": (">=", 0),
        }

        ServerYamlConfChecker.check_conf(conf, default_conf, conf_type,
                                         conf_qualification)

    @staticmethod
    def fill_with_default_conf(conf, default_conf):
        for key, val in default_conf.items():
            if conf.get(key) is None:
                _LOGGER.warning("[CONF] {} not set, use default: {}"
                                .format(key, val))
                conf[key] = val

    @staticmethod
    def check_conf_type(conf, conf_type):
        for key, val in conf_type.items():
            if key not in conf:
                continue
            if not isinstance(conf[key], val):
                raise SystemExit("[CONF] {} must be {} type, but get {}."
                                 .format(key, val, type(conf[key])))

    @staticmethod
    def check_conf_qualification(conf, conf_qualification):
        for key, qualification in conf_qualification.items():
            if key not in conf:
                continue
            if not isinstance(qualification, list):
                qualification = [qualification]
            if not ServerYamlConfChecker.qualification_check(conf[key],
                                                             qualification):
                raise SystemExit("[CONF] {} must be {}, but get {}."
                                 .format(key, ", ".join([
                                     "{} {}"
                                     .format(q[0], q[1]) for q in qualification
                                 ]), conf[key]))

    @staticmethod
    def qualification_check(value, qualifications):
        if not isinstance(qualifications, list):
            qualifications = [qualifications]
        ok = True
        for q in qualifications:
            operator, limit = q
            if operator == "<":
                ok = value < limit
            elif operator == "==":
                ok = value == limit
            elif operator == ">":
                ok = value > limit
            elif operator == "<=":
                ok = value <= limit
            elif operator == ">=":
                ok = value >= limit
            elif operator == "in":
                ok = value in limit
            else:
                raise SystemExit("unknow operator: {}".format(operator))
            if ok == False:
                break
        return ok