"""配置文件路径解析（先于 config 加载，供测试在导入应用前切换配置文件）"""
from __future__ import annotations

from pathlib import Path
from typing import Optional

_CONFIG_FILE: Optional[Path] = None


def project_root() -> Path:
    """项目根目录（含 config/、app/ 的目录）"""
    return Path(__file__).resolve().parents[2]


def set_config_file(path: Path) -> None:
    """指定使用的应用配置文件（仅测试应在导入 app.core.config 之前调用）"""
    global _CONFIG_FILE
    _CONFIG_FILE = Path(path)


def resolved_config_path() -> Path:
    if _CONFIG_FILE is not None:
        return _CONFIG_FILE
    return project_root() / "config" / "app.json"