"""简单的文件锁标记工具。"""

from os import PathLike
from pathlib import Path
import json
import os
from tempfile import NamedTemporaryFile


def is_lock(file_path: str | PathLike[str]) -> bool:
    """判断指定的锁文件是否存在。"""
    return Path(file_path).is_file()


def write_lockfile(file_path: str | PathLike[str]) -> None:
    """创建锁文件；父目录不存在时自动创建。"""
    path = Path(file_path)
    path.parent.mkdir(parents=True, exist_ok=True)
    path.write_text("LOCK", encoding="utf-8")


def claim_json(path: Path, record: dict) -> bool:
    """原子占位并落盘，成功后才允许提交；异常留下记录等待核对。"""
    path.parent.mkdir(parents=True, exist_ok=True)
    try:
        stream = path.open('x', encoding='utf-8')
    except FileExistsError:
        return False
    with stream:
        json.dump(record, stream, ensure_ascii=False)
        stream.flush()
        os.fsync(stream.fileno())
    return True


def replace_json(path: Path, record: dict) -> None:
    """原子替换核对结果，避免其他任务读取到半条记录。"""
    temporary = None
    try:
        with NamedTemporaryFile(mode='w', encoding='utf-8', dir=path.parent, delete=False) as stream:
            temporary = Path(stream.name)
            json.dump(record, stream, ensure_ascii=False)
            stream.flush()
            os.fsync(stream.fileno())
        os.replace(temporary, path)
    finally:
        if temporary is not None:
            temporary.unlink(missing_ok=True)