"""API 측 config IO 헬퍼.

프록시와 동일한 파일을 가리키고, atomic rename 으로 갱신해서 프록시가
mtime polling 으로 안전하게 hot reload 할 수 있게 한다.
"""
from __future__ import annotations

import json
import os
import threading
from pathlib import Path

CONFIG_PATH = Path(os.environ.get("MC_CONFIG_PATH", "/data/config.json"))
LOG_DB = Path(os.environ.get("MC_LOG_DB", "/data/logs.db"))

DEFAULT_CONFIG = {
    "proxy": {"listen_port": 25565, "enabled": True},
    "backend": {"host": "127.0.0.1", "port": 25565},
    "allowed_domains": [
        {"domain": "mc.tkrmagid.kr", "enabled": True, "note": "메인 도메인"}
    ],
}

_lock = threading.Lock()


def load_config() -> dict:
    if not CONFIG_PATH.exists():
        CONFIG_PATH.parent.mkdir(parents=True, exist_ok=True)
        save_config(DEFAULT_CONFIG)
        return json.loads(json.dumps(DEFAULT_CONFIG))
    with _lock:
        with CONFIG_PATH.open("r", encoding="utf-8") as f:
            return json.load(f)


def save_config(cfg: dict) -> None:
    CONFIG_PATH.parent.mkdir(parents=True, exist_ok=True)
    tmp = CONFIG_PATH.with_suffix(".json.tmp")
    with _lock:
        with tmp.open("w", encoding="utf-8") as f:
            json.dump(cfg, f, ensure_ascii=False, indent=2)
        os.replace(tmp, CONFIG_PATH)