# coding=utf-8
# Copyright 2022-present, the HuggingFace Inc. team.
#
# 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.
"""Contains utilities to handle paths in Huggingface Hub."""
from fnmatch import fnmatch
from pathlib import Path
from typing import Callable, Generator, Iterable, List, Optional, TypeVar, Union


T = TypeVar("T")


def filter_repo_objects(
    items: Iterable[T],
    *,
    allow_patterns: Optional[Union[List[str], str]] = None,
    ignore_patterns: Optional[Union[List[str], str]] = None,
    key: Optional[Callable[[T], str]] = None,
) -> Generator[T, None, None]:
    """Filter repo objects based on an allowlist and a denylist.

    Input must be a list of paths (`str` or `Path`) or a list of arbitrary objects.
    In the later case, `key` must be provided and specifies a function of one argument
    that is used to extract a path from each element in iterable.

    Patterns are Unix shell-style wildcards which are NOT regular expressions. See
    https://docs.python.org/3/library/fnmatch.html for more details.

    Args:
        items (`Iterable`):
            List of items to filter.
        allow_patterns (`str` or `List[str]`, *optional*):
            Patterns constituing the allowlist. If provided, item paths must match at
            least one pattern from the allowlist.
        ignore_patterns (`str` or `List[str]`, *optional*):
            Patterns constituing the denylist. If provided, item paths must not match
            any patterns from the denylist.
        key (`Callable[[T], str]`, *optional*):
            Single-argument function to extract a path from each item. If not provided,
            the `items` must already be `str` or `Path`.

    Returns:
        Filtered list of objects, as a generator.

    Raises:
        :class:`ValueError`:
            If `key` is not provided and items are not `str` or `Path`.

    Example usage with paths:
    ```python
    >>> # Filter only PDFs that are not hidden.
    >>> list(filter_repo_objects(
    ...     ["aaa.PDF", "bbb.jpg", ".ccc.pdf", ".ddd.png"],
    ...     allow_patterns=["*.pdf"],
    ...     ignore_patterns=[".*"],
    ... ))
    ["aaa.pdf"]
    ```

    Example usage with objects:
    ```python
    >>> list(filter_repo_objects(
    ... [
    ...     CommitOperationAdd(path_or_fileobj="/tmp/aaa.pdf", path_in_repo="aaa.pdf")
    ...     CommitOperationAdd(path_or_fileobj="/tmp/bbb.jpg", path_in_repo="bbb.jpg")
    ...     CommitOperationAdd(path_or_fileobj="/tmp/.ccc.pdf", path_in_repo=".ccc.pdf")
    ...     CommitOperationAdd(path_or_fileobj="/tmp/.ddd.png", path_in_repo=".ddd.png")
    ... ],
    ... allow_patterns=["*.pdf"],
    ... ignore_patterns=[".*"],
    ... key=lambda x: x.repo_in_path
    ... ))
    [CommitOperationAdd(path_or_fileobj="/tmp/aaa.pdf", path_in_repo="aaa.pdf")]
    ```
    """
    if isinstance(allow_patterns, str):
        allow_patterns = [allow_patterns]

    if isinstance(ignore_patterns, str):
        ignore_patterns = [ignore_patterns]

    if key is None:

        def _identity(item: T) -> str:
            if isinstance(item, str):
                return item
            if isinstance(item, Path):
                return str(item)
            raise ValueError(
                f"Please provide `key` argument in `filter_repo_objects`: `{item}` is"
                " not a string."
            )

        key = _identity  # Items must be `str` or `Path`, otherwise raise ValueError

    for item in items:
        path = key(item)

        # Skip if there's an allowlist and path doesn't match any
        if allow_patterns is not None and not any(
            fnmatch(path, r) for r in allow_patterns
        ):
            continue

        # Skip if there's a denylist and path matches any
        if ignore_patterns is not None and any(
            fnmatch(path, r) for r in ignore_patterns
        ):
            continue

        yield item
