feat: Add command to clean locations

src/fellchensammlung/management/commands/clean_locations.py

@@ -0,0 +1,32 @@
+from django.core.management import BaseCommand
+from fellchensammlung.models import AdoptionNotice, Location
+
+
+class Command(BaseCommand):
+    help = 'Clean up empty locations by re-querying them'
+
+    def add_arguments(self, parser):
+        # Named (optional) arguments
+        parser.add_argument(
+            "--all",
+            action="store_true",
+            help="Re-query all locations, not only where they are empty",
+        )
+
+    def handle(self, *args, **options):
+        adoption_notices_without_location = AdoptionNotice.objects.filter(location__isnull=True)
+        num_of_all = AdoptionNotice.objects.count()
+        num_without_location = adoption_notices_without_location.count()
+        print(f"From {num_of_all} there are {num_without_location} adoption notices without location "
+              f"({num_without_location/num_of_all*100:.2f}%)")
+        for adoption_notice in adoption_notices_without_location:
+            print(f"Searching {adoption_notice.location_string} in Nominatim")
+            location = Location.get_location_from_string(adoption_notice.location_string)
+            if location:
+                adoption_notice.location = location
+                adoption_notice.save()
+
+        adoption_notices_without_location_new = AdoptionNotice.objects.filter(location__isnull=True)
+        num_without_location_new = adoption_notices_without_location_new.count()
+        num_new = num_without_location - num_without_location_new
+        print(f"Added {num_new} new locations")