"""
ONNX 模型 sidecar metadata 辅助工具。
"""

from __future__ import annotations

import json
from pathlib import Path


def model_metadata_path(model_path: str | Path) -> Path:
    return Path(model_path).with_suffix(".meta.json")


def write_model_metadata(model_path: str | Path, metadata: dict) -> Path:
    path = model_metadata_path(model_path)
    payload = {
        "version": 1,
        **metadata,
    }
    path.parent.mkdir(parents=True, exist_ok=True)
    with path.open("w", encoding="utf-8") as f:
        json.dump(payload, f, ensure_ascii=True, indent=2, sort_keys=True)
        f.write("\n")
    return path


def load_model_metadata(model_path: str | Path) -> dict | None:
    path = model_metadata_path(model_path)
    if not path.exists():
        return None
    with path.open("r", encoding="utf-8") as f:
        return json.load(f)