"""Exercise the real forward/reverse migration, including a refused legacy DB."""

import pytest
from django.db import IntegrityError, connection, transaction
from django.db.migrations.executor import MigrationExecutor

from coulomb_social.apps.spaces.models import Space, SpaceMembership
from tests.test_space_permissions import make_member

OLD = ("spaces", "0002_space_visual")
NEW = ("spaces", "0003_space_slug_global_uniq")


def migrate(target):
    executor = MigrationExecutor(connection)
    executor.migrate([target])
    return executor


@pytest.mark.django_db(transaction=True)
def test_forward_refusal_rollback_and_reapply_preserve_rows():
    owner = make_member("migration-owner")
    space = Space.objects.create(
        tenant_id=owner.tenant_id, slug="retained", title="Retained", created_by=owner,
    )
    SpaceMembership.objects.create(space=space, member=owner, role="owner")
    before_spaces = list(Space.objects.order_by("pk").values())
    before_grants = list(SpaceMembership.objects.order_by("pk").values())
    duplicate = None
    try:
        migrate(OLD)
        assert list(Space.objects.order_by("pk").values()) == before_spaces
        assert list(SpaceMembership.objects.order_by("pk").values()) == before_grants
        # The tenant constraint must survive rollback of the global constraint.
        with pytest.raises(IntegrityError), transaction.atomic():
            Space.objects.create(tenant_id=space.tenant_id, slug=space.slug, title="Denied")
        duplicate = Space.objects.create(
            tenant_id="tenant:legacy", slug=space.slug, title="Legacy collision", is_active=False,
        )
        collided = list(Space.objects.order_by("pk").values())
        with pytest.raises(RuntimeError, match="does not rename, merge, or delete"):
            migrate(NEW)
        assert list(Space.objects.order_by("pk").values()) == collided
        assert list(SpaceMembership.objects.order_by("pk").values()) == before_grants
        assert NEW not in MigrationExecutor(connection).loader.applied_migrations
        # Reconciliation here removes only the test's extra synthetic row.
        duplicate.delete()
        duplicate = None
        migrate(NEW)
        with pytest.raises(IntegrityError), transaction.atomic():
            Space.objects.create(tenant_id="tenant:other", slug=space.slug, title="Denied")
        assert list(Space.objects.order_by("pk").values()) == before_spaces
        assert list(SpaceMembership.objects.order_by("pk").values()) == before_grants
        assert NEW in MigrationExecutor(connection).loader.applied_migrations
        migrate(OLD)
        migrate(NEW)
        assert list(Space.objects.order_by("pk").values()) == before_spaces
        assert list(SpaceMembership.objects.order_by("pk").values()) == before_grants
    finally:
        if duplicate is not None:
            duplicate.delete()
        migrate(NEW)