"""Model run registry helpers."""

from __future__ import annotations

import json
from pathlib import Path
from typing import Any


def register_model_run(registry_path: Path, payload: dict[str, Any]) -> dict[str, Any]:
    registry_path.parent.mkdir(parents=True, exist_ok=True)
    if registry_path.exists():
        existing = json.loads(registry_path.read_text(encoding="utf-8"))
        if not isinstance(existing, list):
            existing = []
    else:
        existing = []
    existing.append(payload)
    registry_path.write_text(json.dumps(existing, ensure_ascii=True, indent=2), encoding="utf-8")
    return {"runs": len(existing), "registry_path": str(registry_path)}


def latest_run(registry_path: Path) -> dict[str, Any]:
    if not registry_path.exists():
        return {}
    payload = json.loads(registry_path.read_text(encoding="utf-8"))
    if not payload:
        return {}
    if isinstance(payload, list):
        return payload[-1]
    return {}