import uuid

from sqlalchemy import select
from sqlalchemy.exc import IntegrityError
from sqlalchemy.ext.asyncio import AsyncSession

from app.models import OutboxEvent, Payment
from app.schemas import PaymentCreate, PaymentCreatedEvent


async def create_payment(
    session: AsyncSession,
    request: PaymentCreate,
    idempotency_key: str,
) -> Payment:
    payment_id = uuid.uuid4()
    payment = Payment(
        id=payment_id,
        amount=request.amount,
        currency=request.currency,
        description=request.description,
        metadata_=request.metadata,
        idempotency_key=idempotency_key,
        webhook_url=str(request.webhook_url),
    )
    event = PaymentCreatedEvent(payment_id=payment_id)
    outbox_event = OutboxEvent(
        aggregate_id=payment_id,
        event_type="payment.created",
        payload=event.model_dump(mode="json"),
    )
    session.add_all((payment, outbox_event))

    try:
        await session.commit()
    except IntegrityError:
        await session.rollback()
        existing = await session.scalar(
            select(Payment).where(Payment.idempotency_key == idempotency_key)
        )
        if existing is None:
            raise
        return existing

    return payment


async def get_payment(session: AsyncSession, payment_id: uuid.UUID) -> Payment | None:
    return await session.get(Payment, payment_id)