"""Identity-consumer ownership transfer.

A consumer's ``owner_person_id`` is the accountable human for an outbound
data-pull integration. When the owner offboards, the owner FK is handed
to a named successor (the consumer keeps running under the new owner) —
this is the single write the offboarding handover path and any admin
reassign go through, so the audit trail is identical regardless of
caller.
"""
from __future__ import annotations

import logging
import uuid

from sqlalchemy.ext.asyncio import AsyncSession

from app.audit.service import AuditService
from app.core.exceptions import NotFoundError, ValidationError
from app.identity.consumers.models import IdentityConsumer
from app.identity.person_models import IdentityPerson

logger = logging.getLogger(__name__)


async def transfer_consumer_owner(
    db: AsyncSession,
    *,
    consumer_id: uuid.UUID,
    successor_person_id: uuid.UUID,
    trace_id: str,
    actor_user_id: uuid.UUID | None,
) -> IdentityConsumer:
    """Reassign a consumer's owner to an active successor. Idempotent on
    a no-op (already that owner). Raises if the consumer is gone or the
    successor isn't an active employee."""
    consumer = await db.get(IdentityConsumer, consumer_id)
    if consumer is None or consumer.deleted_at is not None:
        raise NotFoundError("IdentityConsumer", str(consumer_id))
    successor = await db.get(IdentityPerson, successor_person_id)
    if successor is None or successor.deleted_at is not None:
        raise ValidationError("successor_person_id does not reference a known person.")
    if successor.employment_status != "active":
        raise ValidationError(
            "Consumer owner must be an active employee."
        )
    old_owner = consumer.owner_person_id
    if old_owner == successor_person_id:
        return consumer
    consumer.owner_person_id = successor_person_id
    await db.flush()
    await AuditService(db).log(
        trace_id=trace_id,
        actor_type="user" if actor_user_id else "system",
        actor_user_id=actor_user_id,
        action="identity_consumer.owner_transferred",
        status="success",
        resource_type="identity_consumer",
        resource_id=str(consumer.id),
        detail={"slug": consumer.slug, "from": str(old_owner),
                "to": str(successor_person_id)},
    )
    return consumer


__all__ = ["transfer_consumer_owner"]