from __future__ import annotations

import os


def resolve_device() -> str:
    requested = os.getenv("MOUSE_DEMO_DEVICE", "auto").strip().lower()

    if requested == "cpu":
        return "cpu"

    if requested == "cuda":
        import torch
        return "cuda" if torch.cuda.is_available() else "cpu"

    # auto
    import torch
    return "cuda" if torch.cuda.is_available() else "cpu"