from django.core.management.base import BaseCommand
from observations.models import Observation


class Command(BaseCommand):
    help = "Complète le champ 'code' des observations qui n'en ont pas encore."

    def handle(self, *args, **options):
        qs = Observation.objects.filter(code__isnull=True).order_by('pk')
        count = qs.count()
        if not count:
            self.stdout.write(self.style.SUCCESS("Toutes les observations ont déjà un code."))
            return

        updated = 0
        for obs in qs:
            obs.code = f"OBS{obs.pk:05d}"
            updated += 1

        Observation.objects.bulk_update(qs, ['code'])
        self.stdout.write(self.style.SUCCESS(f"{updated} observation(s) mises à jour."))