# Copyright (c) 2021 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.
import importlib
from typing import Any
from typing import Dict
from typing import Text

from deepspeech.utils.log import Log

logger = Log(__name__).getlog()

__all__ = ["dynamic_import", "instance_class"]


def dynamic_import(import_path, alias=dict()):
    """dynamic import module and class

    :param str import_path: syntax 'module_name:class_name'
        e.g., 'deepspeech.models.u2:U2Model'
    :param dict alias: shortcut for registered class
    :return: imported class
    """
    if import_path not in alias and ":" not in import_path:
        raise ValueError("import_path should be one of {} or "
                         'include ":", e.g. "deepspeech.models.u2:U2Model" : '
                         "{}".format(set(alias), import_path))
    if ":" not in import_path:
        import_path = alias[import_path]

    module_name, objname = import_path.split(":")
    m = importlib.import_module(module_name)
    return getattr(m, objname)


def instance_class(module_class, args: Dict[Text, Any]):
    # filter out `val` which is None
    new_args = {key: val for key, val in args.items() if val is not None}
    logger.info(f"Instance: {module_class.__name__} {new_args}.")
    return module_class(**new_args)