"""Delivery event publisher — in-memory + transactional outbox (ADR-006)."""
from __future__ import annotations

from typing import Any, Protocol
from uuid import UUID, uuid4

from sqlalchemy.ext.asyncio import AsyncSession

from shared.events import EventEnvelope, EventStatus

from app.core.config import settings
from app.events.types import HealthcareEventType
from app.models.outbox import OutboxEvent


class EventPublisher(Protocol):
    def publish(
        self,
        *,
        event_type: HealthcareEventType,
        aggregate_type: str,
        aggregate_id: UUID,
        tenant_id: UUID,
        payload: dict[str, Any] | None = None,
    ) -> EventEnvelope: ...


class InMemoryEventPublisher:
    """Records published envelopes for tests and local verification."""

    def __init__(self) -> None:
        self.published: list[EventEnvelope] = []

    def publish(
        self,
        *,
        event_type: HealthcareEventType,
        aggregate_type: str,
        aggregate_id: UUID,
        tenant_id: UUID,
        payload: dict[str, Any] | None = None,
    ) -> EventEnvelope:
        envelope = EventEnvelope(
            event_id=uuid4(),
            event_type=event_type.value,
            aggregate_type=aggregate_type,
            aggregate_id=str(aggregate_id),
            tenant_id=tenant_id,
            source_service=settings.service_name,
            payload=payload or {},
        )
        self.published.append(envelope)
        return envelope

    def record(self, envelope: EventEnvelope) -> EventEnvelope:
        self.published.append(envelope)
        return envelope


class TransactionalEventPublisher:
    """Persist outbox row in the current transaction; mirror to memory in tests."""

    def __init__(
        self, session: AsyncSession, memory: InMemoryEventPublisher | None = None
    ) -> None:
        self.session = session
        if memory is not None:
            self.memory = memory
        elif settings.environment == "test":
            self.memory = get_event_publisher()
        else:
            self.memory = None

    async def publish(
        self,
        *,
        event_type: HealthcareEventType,
        aggregate_type: str,
        aggregate_id: UUID,
        tenant_id: UUID,
        payload: dict[str, Any] | None = None,
    ) -> EventEnvelope:
        envelope = EventEnvelope(
            event_id=uuid4(),
            event_type=event_type.value,
            aggregate_type=aggregate_type,
            aggregate_id=str(aggregate_id),
            tenant_id=tenant_id,
            source_service=settings.service_name,
            payload=payload or {},
        )
        row = OutboxEvent(
            tenant_id=tenant_id,
            event_type=envelope.event_type,
            aggregate_type=aggregate_type,
            aggregate_id=str(aggregate_id),
            payload={
                "event_id": str(envelope.event_id),
                "source_service": settings.service_name,
                **(payload or {}),
            },
            status=EventStatus.PENDING,
        )
        self.session.add(row)
        await self.session.flush()
        if self.memory is not None:
            self.memory.record(envelope)
        return envelope


_default_publisher = InMemoryEventPublisher()


def get_event_publisher() -> InMemoryEventPublisher:
    return _default_publisher


def reset_event_publisher() -> InMemoryEventPublisher:
    global _default_publisher
    _default_publisher = InMemoryEventPublisher()
    return _default_publisher