# Copyright 2010 by Eric Talevich. All rights reserved.
# Copyright 2012 by Wibowo Arindrarto. All rights reserved.
#
# This file is part of the Biopython distribution and governed by your
# choice of the "Biopython License Agreement" or the "BSD 3-Clause License".
# Please see the LICENSE file that should have been included as part of this
# package.
"""Common utility functions for various Bio submodules."""

import os
from typing import Any
from typing import Callable
from typing import cast
from typing import Optional
from typing import Protocol
from typing import TypeVar

# workaround type checking method attributes from https://github.com/python/mypy/issues/2087#issuecomment-587741762

F = TypeVar("F", bound=Callable[..., object])


class _FunctionWithPrevious(Protocol[F]):
    previous: Optional[int]
    __call__: F


def function_with_previous(func: F) -> _FunctionWithPrevious[F]:
    """Decorate a function as having an attribute named 'previous'."""
    function_with_previous = cast(_FunctionWithPrevious[F], func)
    # Make sure the cast isn't a lie.
    function_with_previous.previous = None
    return function_with_previous


def find_test_dir(start_dir: Optional[str] = None) -> str:
    """Find the absolute path of Biopython's Tests directory.

    Arguments:
    start_dir -- Initial directory to begin lookup (default to current dir)

    If the directory is not found up the filesystem's root directory, an
    exception will be raised.

    """
    if not start_dir:
        # no callbacks in function signatures!
        # defaults to the current directory
        # (using __file__ would give the installed Biopython)
        start_dir = "."

    target = os.path.abspath(start_dir)
    while True:
        if os.path.isdir(os.path.join(target, "Bio")) and os.path.isdir(
            os.path.join(target, "Tests")
        ):
            # Good, we're in the Biopython root now
            return os.path.abspath(os.path.join(target, "Tests"))
        # Recurse up the tree
        # TODO - Test this on Windows
        new, tmp = os.path.split(target)
        if target == new:
            # Reached root
            break
        target = new
    raise ValueError(
        f"Not within Biopython source tree: {os.path.abspath(start_dir)!r}"
    )


def run_doctest(target_dir: Optional[str] = None, *args: Any, **kwargs: Any) -> None:
    """Run doctest for the importing module."""
    import doctest

    # default doctest options
    doctest_attributes: dict[str, Any] = {"optionflags": doctest.ELLIPSIS}
    doctest_attributes.update(kwargs)

    cur_dir = os.path.abspath(os.curdir)

    print("Running doctests...")
    try:
        os.chdir(find_test_dir(target_dir))
        doctest.testmod(*args, **doctest_attributes)
    finally:
        # and revert back to initial directory
        os.chdir(cur_dir)
    print("Done")


if __name__ == "__main__":
    run_doctest()