Utils.py

from __future__ import annotations

import asyncio
import json
import typing
import builtins
import os
import subprocess
import sys
import pickle
import functools
import io
import collections
import importlib
import logging
from typing import BinaryIO, Coroutine, Optional, Set, Dict, Any, Union

from yaml import load, load_all, dump, SafeLoader

try:
    from yaml import CLoader as UnsafeLoader
    from yaml import CDumper as Dumper
except ImportError:
    from yaml import Loader as UnsafeLoader
    from yaml import Dumper

if typing.TYPE_CHECKING:
    import tkinter
    import pathlib


def tuplize_version(version: str) -> Version:
    return Version(*(int(piece, 10) for piece in version.split(".")))


class Version(typing.NamedTuple):
    major: int
    minor: int
    build: int


__version__ = "0.3.9"
version_tuple = tuplize_version(__version__)

is_linux = sys.platform.startswith("linux")
is_macos = sys.platform == "darwin"
is_windows = sys.platform in ("win32", "cygwin", "msys")


def int16_as_bytes(value: int) -> typing.List[int]:
    value = value & 0xFFFF
    return [value & 0xFF, (value >> 8) & 0xFF]


def int32_as_bytes(value: int) -> typing.List[int]:
    value = value & 0xFFFFFFFF
    return [value & 0xFF, (value >> 8) & 0xFF, (value >> 16) & 0xFF, (value >> 24) & 0xFF]


def pc_to_snes(value: int) -> int:
    return ((value << 1) & 0x7F0000) | (value & 0x7FFF) | 0x8000


def snes_to_pc(value: int) -> int:
    return ((value & 0x7F0000) >> 1) | (value & 0x7FFF)


RetType = typing.TypeVar("RetType")


def cache_argsless(function: typing.Callable[[], RetType]) -> typing.Callable[[], RetType]:
    assert not function.__code__.co_argcount, "Can only cache 0 argument functions with this cache."

    sentinel = object()
    result: typing.Union[object, RetType] = sentinel

    def _wrap() -> RetType:
        nonlocal result
        if result is sentinel:
            result = function()
        return typing.cast(RetType, result)

    return _wrap


def is_frozen() -> bool:
    return typing.cast(bool, getattr(sys, 'frozen', False))


def local_path(*path: str) -> str:
    """Returns path to a file in the local Archipelago installation or source."""
    if hasattr(local_path, 'cached_path'):
        pass
    elif is_frozen():
        if hasattr(sys, "_MEIPASS"):
            # we are running in a PyInstaller bundle
            local_path.cached_path = sys._MEIPASS  # pylint: disable=protected-access,no-member
        else:
            # cx_Freeze
            local_path.cached_path = os.path.dirname(os.path.abspath(sys.argv[0]))
    else:
        import __main__
        if hasattr(__main__, "__file__") and os.path.isfile(__main__.__file__):
            # we are running in a normal Python environment
            local_path.cached_path = os.path.dirname(os.path.abspath(__main__.__file__))
        else:
            # pray
            local_path.cached_path = os.path.abspath(".")

    return os.path.join(local_path.cached_path, *path)


def home_path(*path: str) -> str:
    """Returns path to a file in the user home's Archipelago directory."""
    if hasattr(home_path, 'cached_path'):
        pass
    elif sys.platform.startswith('linux'):
        home_path.cached_path = os.path.expanduser('~/Archipelago')
        os.makedirs(home_path.cached_path, 0o700, exist_ok=True)
    else:
        # not implemented
        home_path.cached_path = local_path()  # this will generate the same exceptions we got previously

    return os.path.join(home_path.cached_path, *path)


def user_path(*path: str) -> str:
    """Returns either local_path or home_path based on write permissions."""
    if hasattr(user_path, "cached_path"):
        pass
    elif os.access(local_path(), os.W_OK):
        user_path.cached_path = local_path()
    else:
        user_path.cached_path = home_path()
        # populate home from local - TODO: upgrade feature
        if user_path.cached_path != local_path() and not os.path.exists(user_path("host.yaml")):
            import shutil
            for dn in ("Players", "data/sprites"):
                shutil.copytree(local_path(dn), user_path(dn), dirs_exist_ok=True)
            for fn in ("manifest.json", "host.yaml"):
                shutil.copy2(local_path(fn), user_path(fn))

    return os.path.join(user_path.cached_path, *path)


def cache_path(*path: str) -> str:
    """Returns path to a file in the user's Archipelago cache directory."""
    if hasattr(cache_path, "cached_path"):
        pass
    else:
        import appdirs
        cache_path.cached_path = appdirs.user_cache_dir("Archipelago", False)

    return os.path.join(cache_path.cached_path, *path)


def output_path(*path: str) -> str:
    if hasattr(output_path, 'cached_path'):
        return os.path.join(output_path.cached_path, *path)
    output_path.cached_path = user_path(get_options()["general_options"]["output_path"])
    path = os.path.join(output_path.cached_path, *path)
    os.makedirs(os.path.dirname(path), exist_ok=True)
    return path


def open_file(filename: typing.Union[str, "pathlib.Path"]) -> None:
    if is_windows:
        os.startfile(filename)
    else:
        from shutil import which
        open_command = which("open") if is_macos else (which("xdg-open") or which("gnome-open") or which("kde-open"))
        subprocess.call([open_command, filename])


# from https://gist.github.com/pypt/94d747fe5180851196eb#gistcomment-4015118 with some changes
class UniqueKeyLoader(SafeLoader):
    def construct_mapping(self, node, deep=False):
        mapping = set()
        for key_node, value_node in node.value:
            key = self.construct_object(key_node, deep=deep)
            if key in mapping:
                logging.error(f"YAML duplicates sanity check failed{key_node.start_mark}")
                raise KeyError(f"Duplicate key {key} found in YAML. Already found keys: {mapping}.")
            mapping.add(key)
        return super().construct_mapping(node, deep)


parse_yaml = functools.partial(load, Loader=UniqueKeyLoader)
parse_yamls = functools.partial(load_all, Loader=UniqueKeyLoader)
unsafe_parse_yaml = functools.partial(load, Loader=UnsafeLoader)

del load, load_all  # should not be used. don't leak their names


def get_cert_none_ssl_context():
    import ssl
    ctx = ssl.create_default_context()
    ctx.check_hostname = False
    ctx.verify_mode = ssl.CERT_NONE
    return ctx


@cache_argsless
def get_public_ipv4() -> str:
    import socket
    import urllib.request
    ip = socket.gethostbyname(socket.gethostname())
    ctx = get_cert_none_ssl_context()
    try:
        ip = urllib.request.urlopen("https://checkip.amazonaws.com/", context=ctx, timeout=10).read().decode("utf8").strip()
    except Exception as e:
        # noinspection PyBroadException
        try:
            ip = urllib.request.urlopen("https://v4.ident.me", context=ctx, timeout=10).read().decode("utf8").strip()
        except Exception:
            logging.exception(e)
            pass  # we could be offline, in a local game, so no point in erroring out
    return ip


@cache_argsless
def get_public_ipv6() -> str:
    import socket
    import urllib.request
    ip = socket.gethostbyname(socket.gethostname())
    ctx = get_cert_none_ssl_context()
    try:
        ip = urllib.request.urlopen("https://v6.ident.me", context=ctx, timeout=10).read().decode("utf8").strip()
    except Exception as e:
        logging.exception(e)
        pass  # we could be offline, in a local game, or ipv6 may not be available
    return ip


OptionsType = typing.Dict[str, typing.Dict[str, typing.Any]]


@cache_argsless
def get_default_options() -> OptionsType:
    # Refer to host.yaml for comments as to what all these options mean.
    options = {
        "general_options": {
            "output_path": "output",
        },
        "factorio_options": {
            "executable": os.path.join("factorio", "bin", "x64", "factorio"),
            "filter_item_sends": False,
            "bridge_chat_out": True,
        },
        "sni_options": {
            "sni_path": "SNI",
            "snes_rom_start": True,
        },
        "sm_options": {
            "rom_file": "Super Metroid (JU).sfc",
        },
        "soe_options": {
            "rom_file": "Secret of Evermore (USA).sfc",
        },
        "lttp_options": {
            "rom_file": "Zelda no Densetsu - Kamigami no Triforce (Japan).sfc",
        },
        "ladx_options": {
            "rom_file": "Legend of Zelda, The - Link's Awakening DX (USA, Europe) (SGB Enhanced).gbc",
        },
        "server_options": {
            "host": None,
            "port": 38281,
            "password": None,
            "multidata": None,
            "savefile": None,
            "disable_save": False,
            "loglevel": "info",
            "server_password": None,
            "disable_item_cheat": False,
            "location_check_points": 1,
            "hint_cost": 10,
            "release_mode": "goal",
            "collect_mode": "disabled",
            "remaining_mode": "goal",
            "auto_shutdown": 0,
            "compatibility": 2,
            "log_network": 0
        },
        "generator": {
            "enemizer_path": os.path.join("EnemizerCLI", "EnemizerCLI.Core"),
            "player_files_path": "Players",
            "players": 0,
            "weights_file_path": "weights.yaml",
            "meta_file_path": "meta.yaml",
            "spoiler": 3,
            "glitch_triforce_room": 1,
            "race": 0,
            "plando_options": "bosses",
        },
        "minecraft_options": {
            "forge_directory": "Minecraft Forge server",
            "max_heap_size": "2G",
            "release_channel": "release"
        },
        "oot_options": {
            "rom_file": "The Legend of Zelda - Ocarina of Time.z64",
            "rom_start": True
        },
        "dkc3_options": {
            "rom_file": "Donkey Kong Country 3 - Dixie Kong's Double Trouble! (USA) (En,Fr).sfc",
        },
        "smw_options": {
            "rom_file": "Super Mario World (USA).sfc",
        },
        "zillion_options": {
            "rom_file": "Zillion (UE) [!].sms",
            # RetroArch doesn't make it easy to launch a game from the command line.
            # You have to know the path to the emulator core library on the user's computer.
            "rom_start": "retroarch",
        },
        "pokemon_rb_options": {
            "red_rom_file": "Pokemon Red (UE) [S][!].gb",
            "blue_rom_file": "Pokemon Blue (UE) [S][!].gb",
            "rom_start": True
        },
        "ffr_options": {
            "display_msgs": True,
        },
        "lufia2ac_options": {
            "rom_file": "Lufia II - Rise of the Sinistrals (USA).sfc",
        },
        "tloz_options": {
            "rom_file": "Legend of Zelda, The (U) (PRG0) [!].nes",
            "rom_start": True,
            "display_msgs": True,
        },
        "wargroove_options": {
            "root_directory": "C:/Program Files (x86)/Steam/steamapps/common/Wargroove"
        },
        "adventure_options": {
            "rom_file": "ADVNTURE.BIN",
            "display_msgs": True,
            "rom_start": True,
            "rom_args": ""
        },
    }
    return options


def update_options(src: dict, dest: dict, filename: str, keys: list) -> OptionsType:
    for key, value in src.items():
        new_keys = keys.copy()
        new_keys.append(key)
        option_name = '.'.join(new_keys)
        if key not in dest:
            dest[key] = value
            if filename.endswith("options.yaml"):
                logging.info(f"Warning: {filename} is missing {option_name}")
        elif isinstance(value, dict):
            if not isinstance(dest.get(key, None), dict):
                if filename.endswith("options.yaml"):
                    logging.info(f"Warning: {filename} has {option_name}, but it is not a dictionary. overwriting.")
                dest[key] = value
            else:
                dest[key] = update_options(value, dest[key], filename, new_keys)
    return dest


@cache_argsless
def get_options() -> OptionsType:
    filenames = ("options.yaml", "host.yaml")
    locations: typing.List[str] = []
    if os.path.join(os.getcwd()) != local_path():
        locations += filenames  # use files from cwd only if it's not the local_path
    locations += [user_path(filename) for filename in filenames]

    for location in locations:
        if os.path.exists(location):
            with open(location) as f:
                options = parse_yaml(f.read())
            return update_options(get_default_options(), options, location, list())

    raise FileNotFoundError(f"Could not find {filenames[1]} to load options.")


def persistent_store(category: str, key: typing.Any, value: typing.Any):
    path = user_path("_persistent_storage.yaml")
    storage: dict = persistent_load()
    category = storage.setdefault(category, {})
    category[key] = value
    with open(path, "wt") as f:
        f.write(dump(storage, Dumper=Dumper))


def persistent_load() -> typing.Dict[str, dict]:
    storage = getattr(persistent_load, "storage", None)
    if storage:
        return storage
    path = user_path("_persistent_storage.yaml")
    storage: dict = {}
    if os.path.exists(path):
        try:
            with open(path, "r") as f:
                storage = unsafe_parse_yaml(f.read())
        except Exception as e:
            logging.debug(f"Could not read store: {e}")
    if storage is None:
        storage = {}
    persistent_load.storage = storage
    return storage


def get_file_safe_name(name: str) -> str:
    return "".join(c for c in name if c not in '<>:"/\\|?*')


def load_data_package_for_checksum(game: str, checksum: typing.Optional[str]) -> Dict[str, Any]:
    if checksum and game:
        if checksum != get_file_safe_name(checksum):
            raise ValueError(f"Bad symbols in checksum: {checksum}")
        path = cache_path("datapackage", get_file_safe_name(game), f"{checksum}.json")
        if os.path.exists(path):
            try:
                with open(path, "r", encoding="utf-8-sig") as f:
                    return json.load(f)
            except Exception as e:
                logging.debug(f"Could not load data package: {e}")

    # fall back to old cache
    cache = persistent_load().get("datapackage", {}).get("games", {}).get(game, {})
    if cache.get("checksum") == checksum:
        return cache

    # cache does not match
    return {}


def store_data_package_for_checksum(game: str, data: typing.Dict[str, Any]) -> None:
    checksum = data.get("checksum")
    if checksum and game:
        if checksum != get_file_safe_name(checksum):
            raise ValueError(f"Bad symbols in checksum: {checksum}")
        game_folder = cache_path("datapackage", get_file_safe_name(game))
        os.makedirs(game_folder, exist_ok=True)
        try:
            with open(os.path.join(game_folder, f"{checksum}.json"), "w", encoding="utf-8-sig") as f:
                json.dump(data, f, ensure_ascii=False, separators=(",", ":"))
        except Exception as e:
            logging.debug(f"Could not store data package: {e}")


def get_adjuster_settings(game_name: str) -> typing.Dict[str, typing.Any]:
    adjuster_settings = persistent_load().get("adjuster", {}).get(game_name, {})
    return adjuster_settings


@cache_argsless
def get_unique_identifier():
    uuid = persistent_load().get("client", {}).get("uuid", None)
    if uuid:
        return uuid

    import uuid
    uuid = uuid.getnode()
    persistent_store("client", "uuid", uuid)
    return uuid


safe_builtins = frozenset((
    'set',
    'frozenset',
))


class RestrictedUnpickler(pickle.Unpickler):
    def __init__(self, *args, **kwargs):
        super(RestrictedUnpickler, self).__init__(*args, **kwargs)
        self.options_module = importlib.import_module("Options")
        self.net_utils_module = importlib.import_module("NetUtils")
        self.generic_properties_module = importlib.import_module("worlds.generic")

    def find_class(self, module, name):
        if module == "builtins" and name in safe_builtins:
            return getattr(builtins, name)
        # used by MultiServer -> savegame/multidata
        if module == "NetUtils" and name in {"NetworkItem", "ClientStatus", "Hint", "SlotType", "NetworkSlot"}:
            return getattr(self.net_utils_module, name)
        # Options and Plando are unpickled by WebHost -> Generate
        if module == "worlds.generic" and name in {"PlandoItem", "PlandoConnection"}:
            return getattr(self.generic_properties_module, name)
        # pep 8 specifies that modules should have "all-lowercase names" (options, not Options)
        if module.lower().endswith("options"):
            if module == "Options":
                mod = self.options_module
            else:
                mod = importlib.import_module(module)
            obj = getattr(mod, name)
            if issubclass(obj, self.options_module.Option):
                return obj
        # Forbid everything else.
        raise pickle.UnpicklingError(f"global '{module}.{name}' is forbidden")


def restricted_loads(s):
    """Helper function analogous to pickle.loads()."""
    return RestrictedUnpickler(io.BytesIO(s)).load()


class KeyedDefaultDict(collections.defaultdict):
    """defaultdict variant that uses the missing key as argument to default_factory"""
    default_factory: typing.Callable[[typing.Any], typing.Any]

    def __missing__(self, key):
        self[key] = value = self.default_factory(key)
        return value


def get_text_between(text: str, start: str, end: str) -> str:
    return text[text.index(start) + len(start): text.rindex(end)]


def get_text_after(text: str, start: str) -> str:
    return text[text.index(start) + len(start):]


loglevel_mapping = {'error': logging.ERROR, 'info': logging.INFO, 'warning': logging.WARNING, 'debug': logging.DEBUG}


def init_logging(name: str, loglevel: typing.Union[str, int] = logging.INFO, write_mode: str = "w",
                 log_format: str = "[%(name)s at %(asctime)s]: %(message)s",
                 exception_logger: typing.Optional[str] = None):
    import datetime
    loglevel: int = loglevel_mapping.get(loglevel, loglevel)
    log_folder = user_path("logs")
    os.makedirs(log_folder, exist_ok=True)
    root_logger = logging.getLogger()
    for handler in root_logger.handlers[:]:
        root_logger.removeHandler(handler)
        handler.close()
    root_logger.setLevel(loglevel)
    if "a" not in write_mode:
        name += f"_{datetime.datetime.now().strftime('%Y_%m_%d_%H_%M_%S')}"
    file_handler = logging.FileHandler(
        os.path.join(log_folder, f"{name}.txt"),
        write_mode,
        encoding="utf-8-sig")
    file_handler.setFormatter(logging.Formatter(log_format))
    root_logger.addHandler(file_handler)
    if sys.stdout:
        root_logger.addHandler(
            logging.StreamHandler(sys.stdout)
        )

    # Relay unhandled exceptions to logger.
    if not getattr(sys.excepthook, "_wrapped", False):  # skip if already modified
        orig_hook = sys.excepthook

        def handle_exception(exc_type, exc_value, exc_traceback):
            if issubclass(exc_type, KeyboardInterrupt):
                sys.__excepthook__(exc_type, exc_value, exc_traceback)
                return
            logging.getLogger(exception_logger).exception("Uncaught exception",
                                                          exc_info=(exc_type, exc_value, exc_traceback))
            return orig_hook(exc_type, exc_value, exc_traceback)

        handle_exception._wrapped = True

        sys.excepthook = handle_exception

    def _cleanup():
        for file in os.scandir(log_folder):
            if file.name.endswith(".txt"):
                last_change = datetime.datetime.fromtimestamp(file.stat().st_mtime)
                if datetime.datetime.now() - last_change > datetime.timedelta(days=7):
                    try:
                        os.unlink(file.path)
                    except Exception as e:
                        logging.exception(e)
                    else:
                        logging.debug(f"Deleted old logfile {file.path}")
    import threading
    threading.Thread(target=_cleanup, name="LogCleaner").start()
    import platform
    logging.info(
        f"Archipelago ({__version__}) logging initialized"
        f" on {platform.platform()}"
        f" running Python {sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}"
    )


def stream_input(stream, queue):
    def queuer():
        while 1:
            try:
                text = stream.readline().strip()
            except UnicodeDecodeError as e:
                logging.exception(e)
            else:
                if text:
                    queue.put_nowait(text)

    from threading import Thread
    thread = Thread(target=queuer, name=f"Stream handler for {stream.name}", daemon=True)
    thread.start()
    return thread


def tkinter_center_window(window: "tkinter.Tk") -> None:
    window.update()
    x = int(window.winfo_screenwidth() / 2 - window.winfo_reqwidth() / 2)
    y = int(window.winfo_screenheight() / 2 - window.winfo_reqheight() / 2)
    window.geometry(f"+{x}+{y}")


class VersionException(Exception):
    pass


def chaining_prefix(index: int, labels: typing.Tuple[str]) -> str:
    text = ""
    max_label = len(labels) - 1
    while index > max_label:
        text += labels[-1]
        index -= max_label
    return labels[index] + text


# noinspection PyPep8Naming
def format_SI_prefix(value, power=1000, power_labels=("", "k", "M", "G", "T", "P", "E", "Z", "Y")) -> str:
    """Formats a value into a value + metric/si prefix. More info at https://en.wikipedia.org/wiki/Metric_prefix"""
    import decimal
    n = 0
    value = decimal.Decimal(value)
    limit = power - decimal.Decimal("0.005")
    while value >= limit:
        value /= power
        n += 1

    return f"{value.quantize(decimal.Decimal('1.00'))} {chaining_prefix(n, power_labels)}"


def get_fuzzy_results(input_word: str, wordlist: typing.Sequence[str], limit: typing.Optional[int] = None) \
        -> typing.List[typing.Tuple[str, int]]:
    import jellyfish

    def get_fuzzy_ratio(word1: str, word2: str) -> float:
        return (1 - jellyfish.damerau_levenshtein_distance(word1.lower(), word2.lower())
                / max(len(word1), len(word2)))

    limit: int = limit if limit else len(wordlist)
    return list(
        map(
            lambda container: (container[0], int(container[1]*100)),  # convert up to limit to int %
            sorted(
                map(lambda candidate:
                    (candidate,  get_fuzzy_ratio(input_word, candidate)),
                    wordlist),
                key=lambda element: element[1],
                reverse=True)[0:limit]
        )
    )


def open_filename(title: str, filetypes: typing.Sequence[typing.Tuple[str, typing.Sequence[str]]]) \
        -> typing.Optional[str]:
    def run(*args: str):
        return subprocess.run(args, capture_output=True, text=True).stdout.split("\n", 1)[0] or None

    if is_linux:
        # prefer native dialog
        from shutil import which
        kdialog = which("kdialog")
        if kdialog:
            k_filters = '|'.join((f'{text} (*{" *".join(ext)})' for (text, ext) in filetypes))
            return run(kdialog, f"--title={title}", "--getopenfilename", ".", k_filters)
        zenity = which("zenity")
        if zenity:
            z_filters = (f'--file-filter={text} ({", ".join(ext)}) | *{" *".join(ext)}' for (text, ext) in filetypes)
            return run(zenity, f"--title={title}", "--file-selection", *z_filters)

    # fall back to tk
    try:
        import tkinter
        import tkinter.filedialog
    except Exception as e:
        logging.error('Could not load tkinter, which is likely not installed. '
                      f'This attempt was made because open_filename was used for "{title}".')
        raise e
    else:
        root = tkinter.Tk()
        root.withdraw()
        return tkinter.filedialog.askopenfilename(title=title, filetypes=((t[0], ' '.join(t[1])) for t in filetypes))


def messagebox(title: str, text: str, error: bool = False) -> None:
    def run(*args: str):
        return subprocess.run(args, capture_output=True, text=True).stdout.split("\n", 1)[0] or None

    def is_kivy_running():
        if "kivy" in sys.modules:
            from kivy.app import App
            return App.get_running_app() is not None
        return False

    if is_kivy_running():
        from kvui import MessageBox
        MessageBox(title, text, error).open()
        return

    if is_linux and "tkinter" not in sys.modules:
        # prefer native dialog
        from shutil import which
        kdialog = which("kdialog")
        if kdialog:
            return run(kdialog, f"--title={title}", "--error" if error else "--msgbox", text)
        zenity = which("zenity")
        if zenity:
            return run(zenity, f"--title={title}", f"--text={text}", "--error" if error else "--info")

    # fall back to tk
    try:
        import tkinter
        from tkinter.messagebox import showerror, showinfo
    except Exception as e:
        logging.error('Could not load tkinter, which is likely not installed. '
                      f'This attempt was made because messagebox was used for "{title}".')
        raise e
    else:
        root = tkinter.Tk()
        root.withdraw()
        showerror(title, text) if error else showinfo(title, text)
        root.update()


def title_sorted(data: typing.Sequence, key=None, ignore: typing.Set = frozenset(("a", "the"))):
    """Sorts a sequence of text ignoring typical articles like "a" or "the" in the beginning."""
    def sorter(element: Union[str, Dict[str, Any]]) -> str:
        if (not isinstance(element, str)):
            element = element["title"]

        parts = element.split(maxsplit=1)
        if parts[0].lower() in ignore:
            return parts[1].lower()
        else:
            return element.lower()
    return sorted(data, key=lambda i: sorter(key(i)) if key else sorter(i))


def read_snes_rom(stream: BinaryIO, strip_header: bool = True) -> bytearray:
    """Reads rom into bytearray and optionally strips off any smc header"""
    buffer = bytearray(stream.read())
    if strip_header and len(buffer) % 0x400 == 0x200:
        return buffer[0x200:]
    return buffer


_faf_tasks: "Set[asyncio.Task[None]]" = set()


def async_start(co: Coroutine[typing.Any, typing.Any, bool], name: Optional[str] = None) -> None:
    """
    Use this to start a task when you don't keep a reference to it or immediately await it,
    to prevent early garbage collection. "fire-and-forget"
    """
    # https://docs.python.org/3.10/library/asyncio-task.html#asyncio.create_task
    # Python docs:
    # ```
    # Important: Save a reference to the result of [asyncio.create_task],
    # to avoid a task disappearing mid-execution.
    # ```
    # This implementation follows the pattern given in that documentation.

    task = asyncio.create_task(co, name=name)
    _faf_tasks.add(task)
    task.add_done_callback(_faf_tasks.discard)