fix: calculation of percentage increase for trending

Author: danihodovic

django_wtf/core/models/repository_model.py

@@ -1,4 +1,5 @@
-from datetime import datetime, timedelta
+# pylint: disable=redefined-outer-name
+from datetime import date, datetime, timedelta
 
 import hanzidentifier
 from django.contrib.postgres.fields import ArrayField
@@ -65,17 +66,31 @@ def __repr__(self):
     def __str__(self):
         return self.__repr__()
 
-    def stars_since(self, td: timedelta, date=None):
+    def stars_since(self, since: timedelta, date=None):
         if date is None:
             date = datetime.today().date()
-        previous_date = date - td
+        previous_date = date - since
+        return self.stars - self.stars_at(previous_date)
+
+    def stars_at(self, date: date):
         try:
             previous_stars = RepositoryStars.objects.get(
-                created_at=previous_date, repository=self
+                created_at=date, repository=self
             )
         except ObjectDoesNotExist:
             return 0
-        return self.stars - previous_stars.stars
+        return previous_stars.stars
+
+    def stars_relative_increase(self, since: timedelta):
+        """
+        Return the relative increase in stars going back `since` timedelta.
+        Useful for calculating the percentage increase in stars.
+        """
+        before = datetime.today().date() - since
+        try:
+            return (self.stars - self.stars_at(before)) / self.stars_at(before)
+        except ZeroDivisionError:
+            return 0
 
     @property
     def truncated_description(self):

django_wtf/core/queries.py

@@ -17,13 +17,16 @@
 def trending_repositories(days_since, **filters):
     trending = []
     for repo in Repository.valid.filter(stars__gte=20, **filters):
-        stars_in_the_last_week = repo.stars_since(timedelta(days=days_since))
-        if stars_in_the_last_week > 0:
-            setattr(repo, "stars_lately", stars_in_the_last_week)
-            setattr(repo, "stars_quota", repo.stars_lately / repo.stars)  # type: ignore
+        delta = timedelta(days=days_since)
+        stars_gained = repo.stars_since(delta)
+        if stars_gained > 0:
+            setattr(repo, "stars_gained", stars_gained)
+            setattr(
+                repo, "percentage_increase", repo.stars_relative_increase(delta) * 100
+            )
             trending.append(repo)
 
-    return sorted(trending, key=lambda e: e.stars_quota, reverse=True)
+    return sorted(trending, key=lambda e: e.percentage_increase, reverse=True)
 
 
 @cached_as(Contributor, timeout=60 * 60 * 24)

django_wtf/core/templatetags/wtf_tags.py

@@ -6,5 +6,7 @@
 @register.filter
 def to_percent(obj):
     if obj:
-        return f"{obj:.2%}"
-    return obj
+        if obj > 10:
+            return f"{obj:.0f}%"
+        return f"{obj:.2f}%"
+    return ""

django_wtf/core/views/test_trending_repositories_view.py

@@ -24,7 +24,7 @@ def test_trending_by_week(
     res = user_client.get(url + "?trending=7")
     assert res.context["object_list"][0] == more_popular
     assert res.context["object_list"][1] == less_popular
-    assert res.context["object_list"][0].stars_lately == 30
-    assert res.context["object_list"][0].stars_quota == 0.9375
-    assert res.context["object_list"][1].stars_lately == 30
-    assert res.context["object_list"][1].stars_quota == 0.75
+    assert res.context["object_list"][0].stars_gained == 30
+    assert res.context["object_list"][0].percentage_increase == 1500.0
+    assert res.context["object_list"][1].stars_gained == 30
+    assert res.context["object_list"][1].percentage_increase == 300

django_wtf/templates/core/trending_repositories.html

@@ -57,7 +57,7 @@
                             </td>
                             <td class="text-right">
                                 <a href="{{ url }}" target="_blank">
-                                    <strong>{{ repo.stars_quota | to_percent }}</strong> ({{ repo.stars_lately }})
+                                    <strong>{{ repo.percentage_increase | to_percent }}</strong> ({{ repo.stars_gained }})
                                 </a>
                             </td>
                         {% endwith %}