# Copyright 2011 OpenStack Foundation.
# 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 related utilities and helper functions.
"""

import sys
import traceback
from typing import Any


def import_class(import_str: str) -> Any:
    """Returns a class from a string including module and class.

    .. versionadded:: 0.3
    """
    mod_str, _sep, class_str = import_str.rpartition('.')
    __import__(mod_str)
    try:
        return getattr(sys.modules[mod_str], class_str)
    except AttributeError:
        raise ImportError(
            f'Class {class_str} cannot be found '
            f'({traceback.format_exception(*sys.exc_info())})'
        )


def import_object(import_str: str, *args: Any, **kwargs: Any) -> Any:
    """Import a class and return an instance of it.

    .. versionadded:: 0.3
    """
    return import_class(import_str)(*args, **kwargs)


def import_object_ns(
    name_space: str, import_str: str, *args: Any, **kwargs: Any
) -> Any:
    """Tries to import object from default namespace.

    Imports a class and return an instance of it, first by trying
    to find the class in a default namespace, then failing back to
    a full path if not found in the default namespace.

    .. versionadded:: 0.3

    .. versionchanged:: 2.6
       Don't capture :exc:`ImportError` when instanciating the object, only
       when importing the object class.
    """
    import_value = f"{name_space}.{import_str}"
    try:
        cls = import_class(import_value)
    except ImportError:
        cls = import_class(import_str)
    return cls(*args, **kwargs)


def import_module(import_str: str) -> Any:
    """Import a module.

    .. versionadded:: 0.3
    """
    __import__(import_str)
    return sys.modules[import_str]


def import_versioned_module(
    module: str, version: str | int, submodule: str | None = None
) -> Any:
    """Import a versioned module in format {module}.v{version][.{submodule}].

    :param module: the module name.
    :param version: the version number.
    :param submodule: the submodule name.
    :raises ValueError: For any invalid input.

    .. versionadded:: 0.3

    .. versionchanged:: 3.17
       Added *module* parameter.
    """

    # NOTE(gcb) Disallow parameter version include character '.'
    if '.' in f'{version}':
        raise ValueError("Parameter version shouldn't include character '.'.")
    module_str = f'{module}.v{version}'
    if submodule:
        module_str = '.'.join((module_str, submodule))
    return import_module(module_str)


def try_import(import_str: str, default: Any = None) -> Any:
    """Try to import a module and if it fails return default."""
    try:
        return import_module(import_str)
    except ImportError:
        return default


def import_any(module: str, *modules: str) -> Any:
    """Try to import a module from a list of modules.

    :param modules: A list of modules to try and import
    :returns: The first module found that can be imported
    :raises ImportError: If no modules can be imported from list

    .. versionadded:: 3.8
    """
    for module_name in (module,) + modules:
        imported_module = try_import(module_name)
        if imported_module:
            return imported_module

    raise ImportError(
        f'Unable to import any modules from the list {str(modules)}'
    )
