# Copyright 2019 Huawei Technologies Co., Ltd
#
# 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.
# ============================================================================
"""Base file system."""
from abc import ABC, abstractmethod
from collections import namedtuple
StatInfo = namedtuple("Info", ["size", "mtime"])


class BaseFileSystem(ABC):
    """Base class for file systems."""

    @abstractmethod
    def list_dir(self, path):
        """
        Abstract method for listing directories by path.

        Args:
            path (str): Directory path or file path.
        """

    @abstractmethod
    def is_dir(self, path):
        """
        Abstract method for determining if it is a directory.

        Args:
            path (str): Directory path or file path.
        """

    @abstractmethod
    def exists(self, path):
        """
        Abstract method for determining if it exists.

        Args:
            path (str): Directory path or file path.
        """

    @abstractmethod
    def file_stat(self, file_path):
        """
        Abstract method for getting file stat information.

        Args:
            file_path (str): File path.
        """

    @abstractmethod
    def join(self, path, *paths):
        """
        Abstract method for combining paths.

        Args:
            path (str): Directory path.
            *paths (str): Path or paths.
        """