"""审计日志：每次 MCP 调用记录一行（含只读）。"""
import json
import os
from datetime import datetime

_file = None


def init(path):
    global _file
    os.makedirs(os.path.dirname(path), exist_ok=True)
    _file = open(path, "a", encoding="utf-8")
    audit("system", "startup", "", "")


def audit(tool, serial, args_summary, result):
    global _file
    if _file is None:
        return
    rec = {"ts": datetime.now().isoformat(timespec="seconds"),
           "tool": tool, "serial": serial,
           "args": str(args_summary)[:200], "result": str(result)[:200]}
    try:
        _file.write(json.dumps(rec, ensure_ascii=False) + "\n")
        _file.flush()
    except Exception:
        pass