"""
Copyright 2020 The OneFlow 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 os
import importlib.machinery


def _download_file_from_remote_location(fpath: str, url: str) -> None:
    pass


def _is_remote_location_available() -> bool:
    return False


try:
    from torch.hub import load_state_dict_from_url
except ImportError:
    from torch.utils.model_zoo import load_url as load_state_dict_from_url


def _get_extension_path(lib_name):

    lib_dir = os.path.dirname(__file__)
    if os.name == "nt":
        # Register the main torchvision library location on the default DLL path
        import ctypes
        import sys

        kernel32 = ctypes.WinDLL("kernel32.dll", use_last_error=True)
        with_load_library_flags = hasattr(kernel32, "AddDllDirectory")
        prev_error_mode = kernel32.SetErrorMode(0x0001)

        if with_load_library_flags:
            kernel32.AddDllDirectory.restype = ctypes.c_void_p

        if sys.version_info >= (3, 8):
            os.add_dll_directory(lib_dir)
        elif with_load_library_flags:
            res = kernel32.AddDllDirectory(lib_dir)
            if res is None:
                err = ctypes.WinError(ctypes.get_last_error())
                err.strerror += f' Error adding "{lib_dir}" to the DLL directories.'
                raise err

        kernel32.SetErrorMode(prev_error_mode)

    loader_details = (
        importlib.machinery.ExtensionFileLoader,
        importlib.machinery.EXTENSION_SUFFIXES,
    )

    extfinder = importlib.machinery.FileFinder(lib_dir, loader_details)
    ext_specs = extfinder.find_spec(lib_name)
    if ext_specs is None:
        raise ImportError

    return ext_specs.origin
