"""디바이스 선택 (Apple Silicon MPS 우선)."""
import torch

_DEVICE = None


def get_device() -> torch.device:
    global _DEVICE
    if _DEVICE is not None:
        return _DEVICE
    if torch.backends.mps.is_available():
        _DEVICE = torch.device("mps")
    elif torch.cuda.is_available():
        _DEVICE = torch.device("cuda")
    else:
        _DEVICE = torch.device("cpu")
    return _DEVICE


def device_name() -> str:
    d = get_device()
    if d.type == "mps":
        return "Apple Silicon (MPS)"
    if d.type == "cuda":
        return f"CUDA ({torch.cuda.get_device_name(0)})"
    return "CPU"