import json
import logging
from pathlib import Path
from threading import RLock
from typing import Any

logger = logging.getLogger(__name__)

SHARED_USER = "shared"
MA_ALERT_PERIODS = (10, 20, 50, 100, 200)


class UserPrefStore:
    """Per-user JSON bags, one file.

    Namespaces are versioned objects. ``ma_alerts`` is ``{"1d": [200]}``.
    ``user_id`` is ``shared`` until OIDC supplies a subject.
    """

    def __init__(self, path: str | Path):
        self.path = Path(path)
        self._lock = RLock()
        self._by_user: dict[str, dict[str, Any]] = self._load()

    def _load(self) -> dict[str, dict[str, Any]]:
        if not self.path.exists():
            return {}
        try:
            payload = json.loads(self.path.read_text(encoding="utf-8"))
        except Exception:
            logger.warning("Could not read user prefs; starting empty", exc_info=True)
            return {}
        if not isinstance(payload, dict):
            return {}
        loaded: dict[str, dict[str, Any]] = {}
        for user_id, namespaces in payload.items():
            if isinstance(namespaces, dict):
                loaded[str(user_id)] = namespaces
        return loaded

    def _save(self) -> None:
        self.path.parent.mkdir(parents=True, exist_ok=True)
        temporary = self.path.with_suffix(self.path.suffix + ".tmp")
        temporary.write_text(
            json.dumps(self._by_user, indent=2, sort_keys=True) + "\n",
            encoding="utf-8",
        )
        temporary.replace(self.path)

    def get(self, namespace: str, default: Any = None, user_id: str = SHARED_USER) -> Any:
        return self._by_user.get(user_id, {}).get(namespace, default)

    def put(self, namespace: str, value: Any, user_id: str = SHARED_USER) -> Any:
        with self._lock:
            self._by_user.setdefault(user_id, {})[namespace] = value
            self._save()
        return value