import asyncio
from uuid import UUID, uuid4

from .models import CurrentStatus, Monitor, MonitorCreate, MonitorUpdate, utc_now


class MonitorStore:
    """Concurrency-safe process-local monitor state."""

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

    async def create(self, data: MonitorCreate) -> Monitor:
        now = utc_now()
        item = Monitor(
            id=uuid4(), name=data.name, url=data.url, created_at=now,
            updated_at=now, status=CurrentStatus(),
        )
        async with self._lock:
            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 update(self, monitor_id: UUID, data: MonitorUpdate) -> Monitor | None:
        changes = data.model_dump(exclude_unset=True)
        async with self._lock:
            item = self._items.get(monitor_id)
            if item is None:
                return None
            updated = item.model_copy(update={**changes, "updated_at": utc_now()})
            self._items[monitor_id] = updated
            return updated

    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, status: CurrentStatus) -> Monitor | None:
        async with self._lock:
            item = self._items.get(monitor_id)
            if item is None:
                return None
            updated = item.model_copy(update={"status": status})
            self._items[monitor_id] = updated
            return updated