from django.db import migrations, models
import django.db.models.deletion


def backfill_flock_kandang_from_cycle(apps, schema_editor):
    Flock = apps.get_model("farms", "Flock")
    for flock in Flock.objects.select_related("cycle").iterator():
        if flock.cycle_id and flock.kandang_id is None:
            flock.kandang_id = flock.cycle.kandang_id
            flock.save(update_fields=["kandang_id"])


class Migration(migrations.Migration):
    atomic = False

    dependencies = [
        ("farms", "0010_restore_flock_cycle_erd"),
    ]

    operations = [
        migrations.AddField(
            model_name="flock",
            name="kandang",
            field=models.ForeignKey(
                null=True,
                on_delete=django.db.models.deletion.CASCADE,
                related_name="flocks",
                to="farms.kandang",
            ),
        ),
        migrations.RunPython(backfill_flock_kandang_from_cycle, migrations.RunPython.noop),
        migrations.AlterField(
            model_name="flock",
            name="kandang",
            field=models.ForeignKey(
                on_delete=django.db.models.deletion.CASCADE,
                related_name="flocks",
                to="farms.kandang",
            ),
        ),
        migrations.RemoveField(
            model_name="flock",
            name="cycle",
        ),
    ]