feat: compute scores from ratings via management command

pretalx_musicrate/__init__.py

@@ -1 +1 @@
-__version__ = "0.13.1"
+__version__ = "0.14.0"

pretalx_musicrate/management/commands/computescores.py

@@ -0,0 +1,65 @@
+import math
+import statistics
+from operator import itemgetter
+
+from django.core.management.base import BaseCommand, CommandError
+from django_scopes import scope
+from pretalx.event.models import Event
+from pretalx.submission.models import Submission
+
+from ...models import Rating, Score
+
+RATINGS_MIN = 30
+SCALE = list(map(float, map(itemgetter(0), Rating.RATING_CHOICES)))
+
+MEAN = statistics.mean(SCALE)
+STD = math.sqrt(statistics.mean([(i - MEAN) ** 2 for i in SCALE]))
+
+
+class Command(BaseCommand):
+    help = "Compute submission scores from ratings"
+
+    def add_arguments(self, parser):
+        parser.add_argument("event")
+
+    def handle(self, *args, **kwargs):
+        try:
+            event = Event.objects.get(slug=kwargs["event"])
+        except Event.DoesNotExist:
+            raise CommandError(f"no event found with slug '{kwargs['event']}'")
+
+        with scope(event=event):
+            submissions = {}
+
+            for juror in event.jurors.prefetch_related("ratings"):
+                ratings = {
+                    r.submission.code: int(r.rating)
+                    for r in juror.ratings.exclude(rating="")
+                }
+                values = list(ratings.values())
+
+                if len(values) < RATINGS_MIN:
+                    mean = MEAN
+                    std = STD
+                else:
+                    mean = sum(values) / len(values)
+                    std = math.sqrt(
+                        sum([(i - mean) ** 2 for i in values]) / len(values)
+                    )
+
+                for code in ratings:
+                    if code not in submissions:
+                        submissions[code] = []
+                    submissions[code].append((ratings[code] - mean) / std * STD + MEAN)
+
+            for submission in Submission.objects.prefetch_related("score").filter(
+                code__in=submissions.keys()
+            ):
+                try:
+                    score = submission.score
+                except Submission.score.RelatedObjectDoesNotExist:
+                    score = Score(submission=submission)
+
+                ratings = submissions[submission.code]
+                score.value = sum(ratings) / len(ratings)
+                score.save()