"""Kleine Helfer für Focus-Area-Nutzungstypen (ohne Router-/Auth-Abhängigkeiten)."""
from __future__ import annotations

import json
from typing import Any, List


def coerce_usage_type_keys(raw: Any) -> List[str]:
    """json_agg / JSON-Spalte zu list[str] normalisieren."""
    if raw is None:
        return []
    if isinstance(raw, list):
        return [str(x) for x in raw]
    if isinstance(raw, str):
        try:
            data = json.loads(raw)
            return [str(x) for x in data] if isinstance(data, list) else []
        except json.JSONDecodeError:
            return []
    return []
