import asyncio
from uuid import UUID, uuid4

from .models import CheckSnapshot, Monitor, MonitorInput, now


class StoreFullError(Exception):
    pass


class MonitorStore:
    def __init__(self, max_monitors: int) -> None:
        self._items: dict[UUID, Monitor] = {}
        self._lock = asyncio.Lock()
        self._max = max_monitors

    async def create(self, data: MonitorInput) -> Monitor:
        async with self._lock:
            if len(self._items) >= self._max:
                raise StoreFullError
            timestamp = now()
            item = Monitor(id=uuid4(), **data.model_dump(), created_at=timestamp,
                           updated_at=timestamp, revision=1, status=CheckSnapshot())
            self._items[item.id] = item
            return item

    async def list(self) -> list[Monitor]:
        async with self._lock:
            return sorted(self._items.values(), key=lambda item: item.created_at)

    async def get(self, monitor_id: UUID) -> Monitor | None:
        async with self._lock:
            return self._items.get(monitor_id)

    async def replace(self, monitor_id: UUID, data: MonitorInput) -> Monitor | None:
        async with self._lock:
            old = self._items.get(monitor_id)
            if old is None:
                return None
            item = old.model_copy(update={**data.model_dump(), "updated_at": now(),
                                          "revision": old.revision + 1,
                                          "status": CheckSnapshot()})
            self._items[monitor_id] = item
            return item

    async def delete(self, monitor_id: UUID) -> bool:
        async with self._lock:
            return self._items.pop(monitor_id, None) is not None

    async def set_status(self, monitor_id: UUID, revision: int,
                         status: CheckSnapshot) -> Monitor | None:
        async with self._lock:
            old = self._items.get(monitor_id)
            if old is None or old.revision != revision:
                return None
            item = old.model_copy(update={"status": status, "updated_at": now()})
            self._items[monitor_id] = item
            return item