"""In-memory state controller'а."""

from __future__ import annotations

import asyncio
from dataclasses import dataclass, field


@dataclass
class InstanceState:
    name: str
    active_layout: str
    # Future: fps_out, dropped_frames, motion_cameras, last_event_ts


@dataclass
class ControllerState:
    instances: dict[str, InstanceState] = field(default_factory=dict)
    _lock: asyncio.Lock = field(default_factory=asyncio.Lock)

    async def set_layout(self, instance: str, layout: str) -> None:
        async with self._lock:
            st = self.instances.get(instance)
            if st is None:
                st = InstanceState(name=instance, active_layout=layout)
                self.instances[instance] = st
            else:
                st.active_layout = layout

    async def get_layout(self, instance: str) -> str | None:
        async with self._lock:
            st = self.instances.get(instance)
            return st.active_layout if st else None