feat(elections): Pseudonimize tallied elections

elections/migrations/0035_auto_20240711_1424.py

@@ -0,0 +1,44 @@
+# Generated by Django 4.2.12 on 2024-07-11 12:24
+
+import random
+
+from django.db import migrations
+
+alphabet = "abcdefghjkmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ23456789"
+
+
+def generate_password(size):
+    random.seed()
+
+    return "".join(random.choice(alphabet) for _ in range(size))
+
+
+def pseudonymize_users(apps, _):
+    Question = apps.get_model("elections", "Question")
+    Vote = apps.get_model("elections", "Vote")
+
+    votes = set()
+
+    for q in Question.objects.filter(election__tallied=True).prefetch_related(
+        "options__vote_set"
+    ):
+
+        for v in q.voters.all():
+            pseudonym = generate_password(16)
+
+            for opt in q.options.all():
+                for vote in opt.vote_set.filter(user=v):
+                    vote.pseudonymous_user = pseudonym
+                    vote.user = None
+                    votes.add(vote)
+
+    Vote.objects.bulk_update(votes, ["pseudonymous_user", "user"])
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("elections", "0034_vote_pseudonymous_user_alter_vote_user"),
+    ]
+
+    operations = [migrations.RunPython(pseudonymize_users)]