#
#  Copyright 2019 The FATE 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.
#
import importlib
import inspect
from functools import wraps
from pathlib import Path

from filelock import FileLock as _FileLock

from fate_arch.protobuf.python.default_empty_fill_pb2 import DefaultEmptyFillMessage

from fate_flow.component_env_utils import provider_utils
from fate_flow.db.runtime_config import RuntimeConfig
from fate_flow.settings import stat_logger


def serialize_buffer_object(buffer_object):
    # the type is bytes, not str
    serialized_string = buffer_object.SerializeToString()
    if not serialized_string:
        fill_message = DefaultEmptyFillMessage()
        fill_message.flag = 'set'
        serialized_string = fill_message.SerializeToString()
    return serialized_string


def get_proto_buffer_class(buffer_name):
    module_path, base_import_path = provider_utils.get_provider_model_paths(RuntimeConfig.COMPONENT_PROVIDER)
    exception = ModuleNotFoundError(f'no module named {buffer_name}')
    for f in module_path.glob('*.py'):
        try:
            proto_module = importlib.import_module('.'.join([*base_import_path, f.stem]))
            for name, obj in inspect.getmembers(proto_module):
                if inspect.isclass(obj) and name == buffer_name:
                    return obj
        except Exception as e:
            exception = e
            stat_logger.warning(e)
    raise exception


def parse_proto_object(buffer_name, serialized_string, buffer_class=None):
    try:
        if buffer_class is None:
            buffer_class = get_proto_buffer_class(buffer_name)
        buffer_object = buffer_class()
    except Exception as e:
        stat_logger.exception('Can not restore proto buffer object')
        raise e
    buffer_name = type(buffer_object).__name__

    try:
        buffer_object.ParseFromString(serialized_string)
    except Exception as e1:
        stat_logger.exception(e1)
        try:
            DefaultEmptyFillMessage().ParseFromString(serialized_string)
            buffer_object.ParseFromString(bytes())
        except Exception as e2:
            stat_logger.exception(e2)
            raise e1
        else:
            stat_logger.info(f'parse {buffer_name} proto object with default values')
    else:
        stat_logger.info(f'parse {buffer_name} proto object normal')
    return buffer_object


def lock(method):
    @wraps(method)
    def magic(self, *args, **kwargs):
        with self.lock:
            return method(self, *args, **kwargs)
    return magic


def local_cache_required(locking=False):
    def decorator(method):
        @wraps(method)
        def magic(self, *args, **kwargs):
            if not self.exists():
                raise FileNotFoundError(f'Can not found {self.model_id} {self.model_version} model local cache')
            if not locking:
                return method(self, *args, **kwargs)
            with self.lock:
                return method(self, *args, **kwargs)
        return magic
    return decorator


class Locker:

    def __init__(self, directory):
        if isinstance(directory, str):
            directory = Path(directory)
        self.directory = directory
        self.lock = self._lock

    @property
    def _lock(self):
        return FileLock(self.directory / '.lock')

    def __copy__(self):
        return self

    def __deepcopy__(self, memo):
        return self

    # https://docs.python.org/3/library/pickle.html#handling-stateful-objects
    def __getstate__(self):
        state = self.__dict__.copy()
        state.pop('lock')
        return state

    def __setstate__(self, state):
        self.__dict__.update(state)
        self.lock = self._lock


class FileLock(_FileLock):

    def _acquire(self, *args, **kwargs):
        Path(self._lock_file).parent.mkdir(parents=True, exist_ok=True)

        super()._acquire(*args, **kwargs)