[Forum] Display who upvoted/downvoted each post. Closes #346

oioioi/default_settings.py

@@ -865,6 +865,7 @@
 FORUM_THREADS_PER_PAGE = 30
 FORUM_POSTS_PER_PAGE = 30
 FORUM_POST_MAX_LENGTH = 20000
+FORUM_REACTIONS_TO_DISPLAY = 10
 
 # Check seems to be broken. https://stackoverflow.com/a/65578574
 SILENCED_SYSTEM_CHECKS = ['admin.E130']

oioioi/forum/migrations/0013_alter_postreaction_options.py

@@ -0,0 +1,17 @@
+# Generated by Django 4.2.16 on 2025-01-09 17:54
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('forum', '0012_merge_20231222_1900'),
+    ]
+
+    operations = [
+        migrations.AlterModelOptions(
+            name='postreaction',
+            options={'ordering': ['-pk']},
+        ),
+    ]

oioioi/forum/models.py

@@ -6,6 +6,7 @@
 from django.dispatch import receiver
 from django.urls import reverse
 from django.utils import timezone
+from django.conf import settings
 
 from django.utils.translation import gettext_lazy as _
 
@@ -192,22 +193,29 @@ class Post(models.Model):
     class PostsWithReactionsSummaryManager(models.Manager):
         def get_queryset(self):
             qs = super(Post.PostsWithReactionsSummaryManager, self).get_queryset()
-            for field_name, rtype in [
-                ('upvotes_count', 'UPVOTE'),
-                ('downvotes_count', 'DOWNVOTE'),
-            ]:
-                # In Django >=2.0 it can can be simplified with Count(filter=Q(...))
+
+            for rtype, attr_name in POST_REACTION_TO_COUNT_ATTR.items():
                 reaction_count_agg = {
-                    field_name: models.Sum(
-                        models.Case(
-                            models.When(reactions__type_of_reaction=rtype, then=1),
-                            default=0,
-                            output_field=models.IntegerField(),
-                        )
+                    attr_name: models.Count(
+                        'reactions', 
+                        filter=models.Q(reactions__type_of_reaction=rtype)
                     )
                 }
                 qs = qs.annotate(**reaction_count_agg)
 
+            max_count = getattr(settings, 'FORUM_REACTIONS_TO_DISPLAY', 10)
+            for rtype, attr_name in POST_REACTION_TO_PREFETCH_ATTR.items():
+                qs = qs.prefetch_related(
+                    models.Prefetch(
+                        'reactions', 
+                        to_attr=attr_name,
+                        queryset=PostReaction.objects
+                                .filter(type_of_reaction=rtype)
+                                .order_by('-pk')
+                                .select_related('author')[:max_count], 
+                    )
+                )
+
             return qs
 
     objects = PostsWithReactionsSummaryManager()
@@ -256,6 +264,15 @@ def is_reporter_banned(self):
 
         return Ban.is_banned(self.thread.category.forum, self.reported_by)
 
+POST_REACTION_TO_COUNT_ATTR = {
+    "UPVOTE": "upvotes_count",
+    "DOWNVOTE": "downvotes_count",
+}
+
+POST_REACTION_TO_PREFETCH_ATTR = {
+    "UPVOTE": "upvoted_by",
+    "DOWNVOTE": "downvoted_by",
+}
 
 post_reaction_types = EnumRegistry(
     entries=[
@@ -268,6 +285,9 @@ def is_reporter_banned(self):
 class PostReaction(models.Model):
     """PostReaction - represents a reaction to a post on the forum."""
 
+    class Meta(object):
+        ordering = ['-pk']
+
     post = models.ForeignKey(
         Post,
         verbose_name=_("post"),

oioioi/forum/templates/forum/thread-element-footer.html

@@ -1,6 +1,7 @@
 {% load i18n %}
 {% load check_perm %}
 {% load get_user_name %}
+{% load display_reacted_by %}
 {% load user_badge %}
 
 {% url 'forum_post_edit' contest_id=contest.id category_id=category.id thread_id=thread.id post_id=post.id as forum_post_edit_url %}
@@ -18,19 +19,29 @@
         {% if can_interact_with_users %}
             <a href="#" data-post-url="{{ forum_post_toggle_reaction_url }}?reaction=upvote">
         {% endif %}
-        <span class="{% if post.user_upvoted %} text-success {% else %} text-muted {% endif %}">
+
+        <span 
+            class="{% if post.user_upvoted %} text-success {% else %} text-muted {% endif %}"
+            data-toggle="tooltip" title="{% display_reacted_by post "UPVOTE" %}"
+        >
             <i class="fa-solid fa-plus"></i> {{ post.upvotes_count }}
         </span>
+
         {% if can_interact_with_users %}
             </a>
         {% endif %}
 
         {% if can_interact_with_users %}
             <a href="#" data-post-url="{{ forum_post_toggle_reaction_url }}?reaction=downvote">
         {% endif %}
-        <span class="{% if post.user_downvoted %} text-danger {% else %} text-muted {% endif %}">
+
+        <span 
+            class="{% if post.user_downvoted %} text-danger {% else %} text-muted {% endif %}"
+            data-toggle="tooltip" title="{% display_reacted_by post "DOWNVOTE" %}"
+        >
             <i class="fa-solid fa-minus"></i> {{ post.downvotes_count }}
         </span>
+
         {% if can_interact_with_users %}
             </a>
         {% endif %}

oioioi/forum/templatetags/display_reacted_by.py

@@ -0,0 +1,25 @@
+from django import template
+from django.utils.translation import gettext as _
+from oioioi.base.utils import get_user_display_name
+from oioioi.forum.models import POST_REACTION_TO_PREFETCH_ATTR, POST_REACTION_TO_COUNT_ATTR
+from django.conf import settings
+
+register = template.Library()
+
+@register.simple_tag
+def display_reacted_by(post, rtype):
+  if(rtype not in POST_REACTION_TO_PREFETCH_ATTR):
+    raise ValueError('Invalid reaction type in template:' + rtype)
+
+  output = ', '.join([
+    get_user_display_name(reaction.author)
+    for reaction in getattr(post, POST_REACTION_TO_PREFETCH_ATTR[rtype])
+  ])
+
+  count = getattr(post, POST_REACTION_TO_COUNT_ATTR[rtype])
+  max_count = getattr(settings, 'FORUM_REACTIONS_TO_DISPLAY', 10)
+
+  if(count > max_count):
+    output += ' ' +  _('and others.')
+
+  return output

oioioi/forum/tests.py

@@ -402,6 +402,31 @@ def test_paging(self):
             posts_on_last_page,
         )
 
+    def test_reaction_display(self):
+        p = Post(
+            thread=self.thread,
+            content='test',
+            author=self.user,
+        )
+        p.save()
+
+        PostReaction(
+            post_id=p.id, 
+            type_of_reaction='UPVOTE',
+            author=self.user
+        ).save()
+
+        response = self.client.get(self.url, follow=True)
+        self.assertNotContains(response, 'post_reactions')
+        self.assertNotContains(response, 'title="Test User"')
+
+        self.cat.reactions_enabled = True
+        self.cat.save()
+
+        response = self.client.get(self.url, follow=True)
+        self.assertContains(response, 'post_reactions')
+        self.assertContains(response, 'title="Test User"')
+
 
 class TestPost(TestCase):
     fixtures = ['test_users', 'test_contest']
@@ -723,6 +748,38 @@ def count_reactions(r):
         self.assertEqual(1, count_reactions('DOWNVOTE'))
         self.assertEqual(1, self.p.reactions.count())
 
+    def test_reacted_by(self):
+        react_url = self.reverse_post('forum_post_toggle_reaction')
+        upvote_url = react_url + '?reaction=upvote'
+
+        self.cat.reactions_enabled = True
+        self.cat.save()
+
+        self.assertTrue(self.client.login(username='test_user'))
+        self.client.post(upvote_url, follow=True)
+        self.assertTrue(self.client.login(username='test_user2'))
+        self.client.post(upvote_url, follow=True)
+
+        response = self.client.get(self.thread_url, follow=True)
+        self.assertContains(response, 'Test User 2, Test User')
+
+    @override_settings(FORUM_REACTIONS_TO_DISPLAY=2)
+    def test_reacted_by_many_users(self):
+        react_url = self.reverse_post('forum_post_toggle_reaction')
+        upvote_url = react_url + '?reaction=upvote'
+
+        self.cat.reactions_enabled = True
+        self.cat.save()
+
+        self.assertTrue(self.client.login(username='test_user'))
+        self.client.post(upvote_url, follow=True)
+        self.assertTrue(self.client.login(username='test_user2'))
+        self.client.post(upvote_url, follow=True)
+        self.assertTrue(self.client.login(username='test_user3'))
+        self.client.post(upvote_url, follow=True)
+
+        response = self.client.get(self.thread_url, follow=True)
+        self.assertContains(response, 'Test User 3, Test User 2 and others')
 
 class TestBan(TestCase):
     fixtures = ['test_users', 'test_contest']