from django.db import migrations, models
from django.utils import timezone


def backfill_sent_to_department(apps, schema_editor):
    Observation = apps.get_model("observations", "Observation")

    Observation.objects.filter(
        assigned_department__isnull=False
    ).update(sent_to_department=True)
    Observation.objects.filter(
        sent_to_department=True,
        sent_to_department_at__isnull=True,
        forwarded_to_dept_at__isnull=False,
    ).update(sent_to_department_at=models.F("forwarded_to_dept_at"))
    Observation.objects.filter(
        sent_to_department=True, sent_to_department_at__isnull=True
    ).update(sent_to_department_at=timezone.now())


def reverse_backfill(apps, schema_editor):
    Observation = apps.get_model("observations", "Observation")

    Observation.objects.all().update(
        sent_to_department=False, sent_to_department_at=None
    )


class Migration(migrations.Migration):

    dependencies = [
        ("observations", "0004_add_sent_to_department_fields"),
    ]

    operations = [
        migrations.RunPython(backfill_sent_to_department, reverse_backfill),
    ]