import asyncio
from datetime import UTC, datetime
from uuid import UUID

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


class MonitorStore:
    """Concurrency-safe process-local state; all values cross the lock as copies."""

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

    async def create(self, data: MonitorCreate) -> Monitor:
        monitor = Monitor(name=data.name, url=data.url)
        async with self._lock:
            self._items[monitor.id] = monitor
        return monitor.model_copy(deep=True)

    async def list(self) -> list[Monitor]:
        async with self._lock:
            return [item.model_copy(deep=True) for item in self._items.values()]

    async def get(self, monitor_id: UUID) -> Monitor | None:
        async with self._lock:
            item = self._items.get(monitor_id)
            return item.model_copy(deep=True) if item else None

    async def update(self, monitor_id: UUID, data: MonitorUpdate) -> Monitor | None:
        changes = data.model_dump(exclude_unset=True, exclude_none=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": datetime.now(UTC)})
            self._items[monitor_id] = updated
            return updated.model_copy(deep=True)

    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={"current_status": status, "updated_at": datetime.now(UTC)}
            )
            self._items[monitor_id] = updated
            return updated.model_copy(deep=True)