from django.db import migrations


def backfill_voucher_numbers(apps, schema_editor):
    Voucher = apps.get_model('accounting', 'Voucher')

    max_number = (
        Voucher.objects.exclude(number__lte=0)
        .order_by('-number')
        .values_list('number', flat=True)
        .first()
        or 0
    )

    missing_number_vouchers = Voucher.objects.filter(number__lte=0).order_by('created_at', 'id')

    next_number = max_number + 1
    for voucher in missing_number_vouchers:
        voucher.number = next_number
        voucher.save(update_fields=['number'])
        next_number += 1


class Migration(migrations.Migration):
    dependencies = [
        ('accounting', '0006_treasury_fee_fields'),
    ]

    operations = [
        migrations.RunPython(backfill_voucher_numbers, migrations.RunPython.noop),
    ]