# Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
# For details: https://github.com/pylint-dev/pylint/blob/main/LICENSE
# Copyright (c) https://github.com/pylint-dev/pylint/blob/main/CONTRIBUTORS.txt

from __future__ import annotations

import contextlib
import os
import sys
from collections.abc import Generator, Iterator
from copy import copy
from pathlib import Path
from typing import TextIO


@contextlib.contextmanager
def _patch_streams(out: TextIO) -> Iterator[None]:
    """Patch and subsequently reset a text stream."""
    sys.stderr = sys.stdout = out
    try:
        yield
    finally:
        sys.stderr = sys.__stderr__
        sys.stdout = sys.__stdout__


@contextlib.contextmanager
def _test_sys_path(
    replacement_sys_path: list[str] | None = None,
) -> Generator[None, None, None]:
    original_path = sys.path
    try:
        if replacement_sys_path is not None:
            sys.path = copy(replacement_sys_path)
        yield
    finally:
        sys.path = original_path


@contextlib.contextmanager
def _test_cwd(
    current_working_directory: str | Path | None = None,
) -> Generator[None, None, None]:
    original_dir = os.getcwd()
    try:
        if current_working_directory is not None:
            os.chdir(current_working_directory)
        yield
    finally:
        os.chdir(original_dir)


@contextlib.contextmanager
def _test_environ_pythonpath(
    new_pythonpath: str | None = None,
) -> Generator[None, None, None]:
    original_pythonpath = os.environ.get("PYTHONPATH")
    if new_pythonpath:
        os.environ["PYTHONPATH"] = new_pythonpath
    elif new_pythonpath is None and original_pythonpath is not None:
        # If new_pythonpath is None, make sure to delete PYTHONPATH if present
        del os.environ["PYTHONPATH"]
    try:
        yield
    finally:
        if original_pythonpath is not None:
            os.environ["PYTHONPATH"] = original_pythonpath
        elif "PYTHONPATH" in os.environ:
            del os.environ["PYTHONPATH"]


def create_files(paths: list[str], chroot: str = ".") -> None:
    """Creates directories and files found in <path>.

    :param list paths: list of relative paths to files or directories
    :param str chroot: the root directory in which paths will be created

    >>> from os.path import isdir, isfile
    >>> isdir('/tmp/a')
    False
    >>> create_files(['a/b/foo.py', 'a/b/c/', 'a/b/c/d/e.py'], '/tmp')
    >>> isdir('/tmp/a')
    True
    >>> isdir('/tmp/a/b/c')
    True
    >>> isfile('/tmp/a/b/c/d/e.py')
    True
    >>> isfile('/tmp/a/b/foo.py')
    True
    """
    dirs, files = set(), set()
    for path in paths:
        path = os.path.join(chroot, path)
        filename = os.path.basename(path)
        # path is a directory path
        if not filename:
            dirs.add(path)
        # path is a filename path
        else:
            dirs.add(os.path.dirname(path))
            files.add(path)
    for dirpath in dirs:
        if not os.path.isdir(dirpath):
            os.makedirs(dirpath)
    for filepath in files:
        with open(filepath, "w", encoding="utf-8"):
            pass