import base64, json
from typing import Any

def encode_cursor(values: list[Any] | None, desc_flags: list[bool], backward: bool) -> str | None:
    if not values:
        return None
    payload = {"v": values, "d": desc_flags, "b": backward}
    return base64.urlsafe_b64encode(json.dumps(payload).encode()).decode()

def decode_cursor(token: str | None) -> tuple[list[Any] | None, bool] | tuple[None, bool]:
    if not token:
        return None, False
    try:
        obj = json.loads(base64.urlsafe_b64decode(token.encode()).decode())
        vals = obj.get("v")
        backward = bool(obj.get("b", False))
        if isinstance(vals, list):
            return vals, backward
    except Exception:
        pass
    return None, False