from __future__ import annotations

import json
from datetime import UTC, datetime
from pathlib import Path
from threading import Lock
from typing import Any


class ConversationLogStore:
    """Append-only local audit log for chat and tool activity."""

    def __init__(self, path: str | Path) -> None:
        self.path = Path(path)
        self._lock = Lock()

    def append(self, event: dict[str, Any]) -> None:
        record = {"timestamp": datetime.now(UTC).isoformat(), **_safe(event)}
        self.path.parent.mkdir(parents=True, exist_ok=True)
        with self._lock, self.path.open("a", encoding="utf-8") as stream:
            stream.write(json.dumps(record, ensure_ascii=True, default=str) + "\n")


def _safe(value: Any) -> Any:
    if isinstance(value, dict):
        return {str(k): _safe(v) for k, v in value.items()}
    if isinstance(value, list):
        return [_safe(v) for v in value]
    return value if isinstance(value, (str, int, float, bool)) or value is None else str(value)