"""바이너리·npz 파일을 원자적으로 저장하는 공통 유틸리티."""

import os
import tempfile
from pathlib import Path

import numpy as np


def atomic_write_bytes(path: str | Path, payload: bytes) -> None:
    """같은 디렉터리의 임시 파일을 교체하여 바이트를 원자적으로 저장한다."""
    target = Path(path)
    target.parent.mkdir(parents=True, exist_ok=True)
    temporary_path: Path | None = None
    try:
        with tempfile.NamedTemporaryFile(
            mode="wb",
            dir=target.parent,
            prefix=f".{target.name}.",
            suffix=".tmp",
            delete=False,
        ) as temporary:
            temporary.write(payload)
            temporary.flush()
            os.fsync(temporary.fileno())
            temporary_path = Path(temporary.name)
        os.replace(temporary_path, target)
        temporary_path = None
    finally:
        if temporary_path is not None:
            temporary_path.unlink(missing_ok=True)


def atomic_write_npz(path: str | Path, **arrays: np.ndarray) -> None:
    """같은 디렉터리의 임시 파일을 교체하여 압축 npz를 원자적으로 저장한다."""
    target = Path(path)
    target.parent.mkdir(parents=True, exist_ok=True)
    temporary_path: Path | None = None
    try:
        with tempfile.NamedTemporaryFile(
            mode="wb",
            dir=target.parent,
            prefix=f".{target.name}.",
            suffix=".tmp",
            delete=False,
        ) as temporary:
            np.savez_compressed(temporary, **arrays)
            temporary.flush()
            os.fsync(temporary.fileno())
            temporary_path = Path(temporary.name)
        os.replace(temporary_path, target)
        temporary_path = None
    finally:
        if temporary_path is not None:
            temporary_path.unlink(missing_ok=True)