import asyncio
import contextvars
import functools
import getpass
from typing import Any, Callable, Optional, TypeVar

T = TypeVar("T")


# TODO When switching to 3.9, use asyncio.to_thread instead of this
async def to_thread(func: Callable[..., T], *args: Any, **kwargs: Any) -> T:
    # https://github.com/python/cpython/blob/8d47f92d46a92a5931b8f3dcb4a484df672fc4de/Lib/asyncio/threads.py
    loop = asyncio.get_event_loop()
    ctx = contextvars.copy_context()
    func_call = functools.partial(ctx.run, func, *args, **kwargs)
    return await loop.run_in_executor(None, func_call)  # type: ignore


async def ainput(prompt: str) -> str:
    return await to_thread(lambda: input(prompt))


async def agetpass(prompt: str) -> str:
    return await to_thread(lambda: getpass.getpass(prompt))


async def prompt_yes_no(query: str, default: Optional[bool]) -> bool:
    """
    Asks the user a yes/no question and returns their choice.
    """

    if default is True:
        query += " [Y/n] "
    elif default is False:
        query += " [y/N] "
    else:
        query += " [y/n] "

    while True:
        response = (await ainput(query)).strip().lower()
        if response == "y":
            return True
        elif response == "n":
            return False
        elif response == "" and default is not None:
            return default

        print("Please answer with 'y' or 'n'.")