Add Managers to automatically create CriterionRatings on Creation of Sport and Criterion

unisportomat/quiz/management/commands/seed_db.py

@@ -74,7 +74,7 @@ class Command(BaseCommand):
             "Bouldern",
         ]
         for name in sports_names:
-            Sport(name=name).save()
+            Sport.objects.create_sport(name=name).save()
 
         # Create criteria
         criteria_names = [
@@ -85,7 +85,7 @@ class Command(BaseCommand):
             "Kampfsport",
         ]
         for name in criteria_names:
-            Criterion(name=name).save()
+            Criterion.objects.create_criterion(name=name).save()
 
         # Create ratings for all sports and criterions
         for sport in Sport.objects.all():

unisportomat/quiz/models.py

 """ Model definitions for the quiz """
 
 from django.core.validators import MaxValueValidator, MinValueValidator
+from django.core.exceptions import ValidationError
 from django.db import models
 
 
+def validate_rating(value):
+    """
+    TODO: Validations are only run when using Model Forms.
+    """
+
+    print("Validating")
+    if not (value <= 10 or value >= 1 or value == -1):
+        raise ValidationError(u"%s is not a valid rating!" % value)
+
+
 class CriterionRating(models.Model):
     """
     This is the relation between Sport and Criterion.
@@ -11,9 +22,7 @@ class CriterionRating(models.Model):
     To see it's usage check Sport.rate() and Sport.get_rating()
     """
 
-    rating = models.IntegerField(
-        validators=[MaxValueValidator(10), MinValueValidator(1)]
-    )
+    rating = models.IntegerField(validators=[validate_rating])
     criterion = models.ForeignKey("Criterion", on_delete=models.CASCADE)
     sport = models.ForeignKey("Sport", on_delete=models.CASCADE)
 
@@ -21,6 +30,25 @@ class CriterionRating(models.Model):
         return str(self.sport) + " - " + str(self.criterion) + ": " + str(self.rating)
 
 
+class SportManager(models.Manager):
+    """
+    Manages Creation of Sport Objects
+    Since every Criterion Connection needs to be present in the DB at all times,
+    the connections are made at creation of the Sport object. For this, Sport objects need to be
+    created through this Manager Class.
+
+    Docs: https://docs.djangoproject.com/en/3.2/ref/models/instances/#creating-objects
+    """
+
+    def create_sport(self, **kwargs):
+        sport = self.create(**kwargs)
+
+        for crit in Criterion.objects.iterator():
+            sport.rate(crit, -1)
+
+        return sport
+
+
 class Sport(models.Model):
     """
     Defines a Sport with name, url that leads to the booking page.
@@ -32,6 +60,8 @@ class Sport(models.Model):
     url = models.URLField()
     criteria_ratings = models.ManyToManyField("Criterion", through="CriterionRating")
 
+    objects = SportManager()
+
     def __str__(self):
         return self.name
 
@@ -50,6 +80,28 @@ class Sport(models.Model):
         return criterion_rating.rating
 
 
+class CriterionManager(models.Manager):
+    """
+    Manages Creation of Criterion Objects
+    Since every Sport Object needs to be rated in every criterion,
+    when a new Criterion is created, every Sport object needs to be rated for that Criterion.
+    As a default Value, -1 is entered so that it can be recognized that no true value is given.
+
+    Docs: https://docs.djangoproject.com/en/3.2/ref/models/instances/#creating-objects
+    """
+
+    def create_criterion(self, **kwargs):
+        crit = Criterion(**kwargs)
+
+        # Criterion needs to be saved before it can be connected to a sport
+        crit.save()
+
+        for sport in Sport.objects.iterator():
+            sport.rate(crit, -1)
+
+        return crit
+
+
 class Criterion(models.Model):
     """
     Defines a Sport property that is used a a criterion for our quiz.
@@ -58,6 +110,8 @@ class Criterion(models.Model):
 
     name = models.TextField()
 
+    objects = CriterionManager()
+
     def __str__(self):
         return self.name
 

unisportomat/quiz/views.py

@@ -121,7 +121,7 @@ class SmallSportListView(viewsets.ViewSet):
 
         print(data_dict)
 
-        new_sport = Sport()
+        new_sport = Sport.objects.create_sport()
 
         new_sport.name = data_dict["name"]
         new_sport.url = data_dict["url"]