"""
配置加载

从 scripts/data/config.json 读取用户配置，环境变量可覆盖系统 URL 与用户字段。
"""

import json
import os
from pathlib import Path

# 项目根 = src/config.py 的上上级（曾多写一层 parent，导致解析到项目之外、凭据恒为空）
_CONFIG_PATH = Path(__file__).resolve().parent.parent / "scripts" / "data" / "config.json"

# 会话级配置允许覆盖的用户相关字段白名单（含密码）

# 前端安全的配置字段白名单（不含密码）
SAFE_CONFIG_KEYS = frozenset(
    {
        "username",
        "default_name",
        "default_card_no",
        "default_person_id",
    }
)

# 模块级配置缓存
_config_cache: dict[str, str | Path] | None = None


def _read_config() -> dict[str, str | Path]:
    """读取并合并配置，缺失字段使用默认值"""
    raw = {}
    if _CONFIG_PATH.exists():
        with open(_CONFIG_PATH, encoding="utf-8") as f:
            raw = json.load(f)

    project_root = _CONFIG_PATH.parent

    return {
        "sso_login_url": os.environ.get("SSO_LOGIN_URL", "https://tyrz.fynu.edu.cn/sso/login"),
        "portal_url": os.environ.get("PORTAL_URL", "https://tyrz.fynu.edu.cn/oshall"),
        "reimburse_url": os.environ.get("REIMBURSE_URL", "http://210.45.32.214:8081"),
        "reimburse_page": os.environ.get("REIMBURSE_PAGE", "/expen/common/common?v=4.0"),
        "travel_page": os.environ.get("TRAVEL_PAGE", "/expen/travel/travel?v=4.0"),
        "username": raw.get("username", ""),
        "password": raw.get("password", ""),
        "default_name": raw.get("default_name", ""),
        "default_card_no": raw.get("default_card_no", ""),
        "default_person_id": raw.get("default_person_id", ""),
        "upload_pin": os.environ.get("UPLOAD_PIN") or raw.get("upload_pin", ""),
        "attachment_dir": project_root / "attachments",
    }


def load_config() -> dict[str, str | Path]:
    """加载并合并配置，使用模块级缓存避免重复读取文件"""
    global _config_cache
    if _config_cache is None:
        _config_cache = _read_config()
    return dict(_config_cache)


def clear_config_cache() -> None:
    """清除配置缓存（测试或配置变更时调用）"""
    global _config_cache
    _config_cache = None