"""Per-turn orchestration trace (Open-Trace bonus).

Enable by setting VN_TRACE=runs/<name>.jsonl. Each line records the player input, the assembled
context, the raw directive output, applied effects, and the painter prompts/seeds — clean and
shareable as a Hub dataset because the state is structured.
"""

from __future__ import annotations

import json
import time
from pathlib import Path
from typing import Any


class Tracer:
    def __init__(self, path: str | None) -> None:
        self.path = Path(path) if path else None
        if self.path:
            self.path.parent.mkdir(parents=True, exist_ok=True)

    def log(self, **record: Any) -> None:
        if not self.path:
            return
        record["ts"] = time.time()
        with self.path.open("a", encoding="utf-8") as f:
            f.write(json.dumps(record, ensure_ascii=False, default=str) + "\n")