"""События домена и подписка модулей (задел; пока in-memory)."""

from __future__ import annotations

from collections.abc import Awaitable, Callable
from dataclasses import dataclass, field
from datetime import datetime, timezone
from typing import Protocol
from uuid import UUID

from onguard24.domain.entities import Alert


@dataclass
class DomainEvent:
    """Базовый тип события."""

    name: str = "domain.generic"
    occurred_at: datetime = field(default_factory=lambda: datetime.now(timezone.utc))


@dataclass
class AlertReceived(DomainEvent):
    """Алерт принят в систему (после нормализации)."""

    name: str = "alert.received"
    alert: Alert | None = None
    raw_payload_ref: UUID | None = None
    grafana_org_slug: str | None = None
    service_name: str | None = None


Handler = Callable[[DomainEvent], Awaitable[None]]


class Module(Protocol):
    """Модуль (schedules, contacts, …) может подписаться на события."""

    @property
    def name(self) -> str: ...

    async def on_event(self, event: DomainEvent) -> None: ...


class EventBus(Protocol):
    async def publish(self, event: DomainEvent) -> None: ...

    def subscribe(self, event_name: str, handler: Handler) -> None: ...


class InMemoryEventBus:
    """Простая шина для тестов и раннего прототипа."""

    def __init__(self) -> None:
        self._subs: dict[str, list[Handler]] = {}

    def subscribe(self, event_name: str, handler: Handler) -> None:
        self._subs.setdefault(event_name, []).append(handler)

    async def publish(self, event: DomainEvent) -> None:
        for h in self._subs.get(event.name, []):
            await h(event)

    async def publish_alert_received(
        self,
        alert: Alert,
        raw_payload_ref: UUID | None = None,
        *,
        grafana_org_slug: str | None = None,
        service_name: str | None = None,
    ) -> None:
        ev = AlertReceived(
            alert=alert,
            raw_payload_ref=raw_payload_ref,
            grafana_org_slug=grafana_org_slug,
            service_name=service_name,
        )
        await self.publish(ev)