# Generated by Django 4.2.30 on 2026-09-27 10:57

from django.db import migrations, models


def deduplicate_instances(apps, schema_editor):
    Instance = apps.get_model('instances', 'Instance')
    UserInstance = apps.get_model('accounts', 'UserInstance')
    from django.db.models import Count, Q
    import uuid as uuid_mod

    # Assign distinct UUIDs to legacy/corrupt records with null, empty, or whitespace UUIDs
    # so they are not treated as duplicates or collapsed together
    empty_uuid_instances = Instance.objects.filter(
        Q(uuid__isnull=True) | Q(uuid="") | Q(uuid__regex=r"^\s*$")
    )
    for inst in empty_uuid_instances:
        inst.uuid = str(uuid_mod.uuid4())
        inst.save(update_fields=['uuid'])

    duplicates = (
        Instance.objects.exclude(uuid__isnull=True).exclude(uuid="")
        .values('compute_id', 'uuid')
        .annotate(count=Count('id'))
        .filter(count__gt=1)
    )
    for item in duplicates:
        instances = list(Instance.objects.filter(
            compute_id=item['compute_id'],
            uuid=item['uuid']
        ).order_by('-id'))
        primary = instances[0]
        # Preserve is_template and non-default drbd across duplicate rows
        merged_is_template = any(getattr(inst, 'is_template', False) for inst in instances)
        non_default_drbd = next((inst.drbd for inst in instances if inst.drbd and inst.drbd != 'None'), None)
        updated = False
        if primary.is_template != merged_is_template:
            primary.is_template = merged_is_template
            updated = True
        if non_default_drbd and primary.drbd != non_default_drbd:
            primary.drbd = non_default_drbd
            updated = True
        if updated:
            primary.save()

        for dup in instances[1:]:
            # Reassign or merge UserInstance relationships
            for ui in UserInstance.objects.filter(instance=dup):
                existing = UserInstance.objects.filter(instance=primary, user=ui.user).first()
                if not existing:
                    ui.instance = primary
                    ui.save()
                else:
                    # Merge permissions with logical OR so no stronger permission is lost
                    updated = False
                    if ui.is_change and not existing.is_change:
                        existing.is_change = True
                        updated = True
                    if ui.is_delete and not existing.is_delete:
                        existing.is_delete = True
                        updated = True
                    if ui.is_vnc and not existing.is_vnc:
                        existing.is_vnc = True
                        updated = True
                    if updated:
                        existing.save()
                    ui.delete()
            dup.delete()


class Migration(migrations.Migration):

    dependencies = [
        ('instances', '0011_createinstance_migrateinstance'),
        ('accounts', '0001_initial'),
    ]

    operations = [
        migrations.RunPython(deduplicate_instances, migrations.RunPython.noop),
        migrations.AlterField(
            model_name='flavor',
            name='id',
            field=models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID'),
        ),
        migrations.AlterField(
            model_name='instance',
            name='id',
            field=models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID'),
        ),
        migrations.AddConstraint(
            model_name='instance',
            constraint=models.UniqueConstraint(fields=('compute', 'uuid'), name='unique_compute_uuid'),
        ),
    ]