from __future__ import annotations

import json
import os
from pathlib import Path
from typing import Any


class StateStore:
    """Small JSON store for UI preferences; native runtime state is not stored here."""

    def __init__(self) -> None:
        storage_root = os.getenv("FLET_APP_STORAGE_DATA")
        root = Path(
            os.getenv(
                "VPNAPP_STATE_DIR",
                storage_root or str(Path.home() / ".vpnapp"),
            )
        )
        root.mkdir(parents=True, exist_ok=True)
        self.path = root / "ui-state.json"

    def load(self) -> dict[str, Any]:
        try:
            return json.loads(self.path.read_text(encoding="utf-8"))
        except (FileNotFoundError, json.JSONDecodeError):
            return {}

    def save(self, value: dict[str, Any]) -> None:
        temporary = self.path.with_suffix(".tmp")
        temporary.write_text(json.dumps(value, ensure_ascii=False, indent=2), encoding="utf-8")
        temporary.replace(self.path)