PCR comments

backend/courses/migrations/0064_auto_20240120_1914.py

@@ -0,0 +1,45 @@
+# Generated by Django 3.2.23 on 2024-01-21 00:14
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ("courses", "0063_auto_20231212_1750"),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name="section",
+            name="activity",
+            field=models.CharField(
+                choices=[
+                    ("", "Undefined"),
+                    ("CLN", "Clinic"),
+                    ("CRT", "Clinical Rotation"),
+                    ("DAB", "Dissertation Abroad"),
+                    ("DIS", "Dissertation"),
+                    ("DPC", "Doctoral Program Exchange"),
+                    ("FLD", "Field Work"),
+                    ("HYB", "Hybrid"),
+                    ("IND", "Independent Study"),
+                    ("LAB", "Lab"),
+                    ("LEC", "Lecture"),
+                    ("MST", "Masters Thesis"),
+                    ("ONL", "Online"),
+                    ("PRC", "Practicum"),
+                    ("REC", "Recitation"),
+                    ("SEM", "Seminar"),
+                    ("SRT", "Senior Thesis"),
+                    ("STU", "Studio"),
+                ],
+                db_index=True,
+                help_text='The section activity, e.g. `LEC` for CIS-120-001 (2020A). Options and meanings: <table width=100%><tr><td>""</td><td>"Undefined"</td></tr><tr><td>"CLN"</td><td>"Clinic"</td></tr><tr><td>"CRT"</td><td>"Clinical Rotation"</td></tr><tr><td>"DAB"</td><td>"Dissertation Abroad"</td></tr><tr><td>"DIS"</td><td>"Dissertation"</td></tr><tr><td>"DPC"</td><td>"Doctoral Program Exchange"</td></tr><tr><td>"FLD"</td><td>"Field Work"</td></tr><tr><td>"HYB"</td><td>"Hybrid"</td></tr><tr><td>"IND"</td><td>"Independent Study"</td></tr><tr><td>"LAB"</td><td>"Lab"</td></tr><tr><td>"LEC"</td><td>"Lecture"</td></tr><tr><td>"MST"</td><td>"Masters Thesis"</td></tr><tr><td>"ONL"</td><td>"Online"</td></tr><tr><td>"PRC"</td><td>"Practicum"</td></tr><tr><td>"REC"</td><td>"Recitation"</td></tr><tr><td>"SEM"</td><td>"Seminar"</td></tr><tr><td>"SRT"</td><td>"Senior Thesis"</td></tr><tr><td>"STU"</td><td>"Studio"</td></tr></table>',
+                max_length=50,
+            ),
+        )
+    ]

backend/courses/migrations/0066_merge_20240426_0627.py

@@ -0,0 +1,13 @@
+# Generated by Django 3.2.23 on 2024-04-26 10:27
+
+from django.db import migrations
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("courses", "0064_auto_20240120_1914"),
+        ("courses", "0065_topic_historical_probabilities_fall_and_more"),
+    ]
+
+    operations = []

backend/courses/migrations/0067_comment.py

@@ -0,0 +1,82 @@
+# Generated by Django 3.2.23 on 2024-04-26 10:27
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ("courses", "0066_merge_20240426_0627"),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name="Comment",
+            fields=[
+                (
+                    "id",
+                    models.AutoField(
+                        auto_created=True, primary_key=True, serialize=False, verbose_name="ID"
+                    ),
+                ),
+                ("text", models.TextField()),
+                ("created_at", models.DateTimeField(auto_now_add=True)),
+                ("modified_at", models.DateTimeField(auto_now=True)),
+                ("path", models.TextField(db_index=True)),
+                (
+                    "author",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=django.db.models.deletion.SET_NULL,
+                        related_name="comments",
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+                (
+                    "base",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=django.db.models.deletion.SET_NULL,
+                        to="courses.comment",
+                    ),
+                ),
+                (
+                    "downvotes",
+                    models.ManyToManyField(
+                        help_text="The number of downvotes a comment gets.",
+                        related_name="downvotes",
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+                (
+                    "parent",
+                    models.ForeignKey(
+                        null=True,
+                        on_delete=django.db.models.deletion.SET_NULL,
+                        related_name="children",
+                        to="courses.comment",
+                    ),
+                ),
+                (
+                    "section",
+                    models.ForeignKey(
+                        help_text="\nThe section with which a comment is associated. Section was chosen instead of topics for\nhosting comments because topics are SOFT STATE and are recomputed regularly.\n",
+                        null=True,
+                        on_delete=django.db.models.deletion.CASCADE,
+                        to="courses.section",
+                    ),
+                ),
+                (
+                    "upvotes",
+                    models.ManyToManyField(
+                        help_text="The number of upvotes a comment gets.",
+                        related_name="upvotes",
+                        to=settings.AUTH_USER_MODEL,
+                    ),
+                ),
+            ],
+        ),
+    ]

backend/courses/migrations/0068_comment_instructor.py

@@ -0,0 +1,24 @@
+# Generated by Django 5.0.2 on 2024-10-27 17:06
+
+import django.db.models.deletion
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("courses", "0067_comment"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="comment",
+            name="instructor",
+            field=models.ForeignKey(
+                help_text="\nThe instructor with which a comment is associated. Instructor was chosen instead of topics\nfor hosting comments because topics are SOFT STATE and are recomputed regularly.\n",
+                null=True,
+                on_delete=django.db.models.deletion.SET_NULL,
+                to="courses.instructor",
+            ),
+        ),
+    ]

backend/courses/models.py

@@ -1540,3 +1540,79 @@ def __str__(self):
         return (
             f"Friendship(Sender: {self.sender}, Recipient: {self.recipient}, Status: {self.status})"
         )
+
+
+class Comment(models.Model):
+    """
+    A single comment associated with a topic to be displayed on PCR. Comments support replies
+    through the parent_id and path fields. The path field allows for efficient database querying
+    and can indicate levels of nesting and can make pagination simpler. Idea implemented based
+    on this guide: https://blog.miguelgrinberg.com/post/implementing-user-comments-with-sqlalchemy.
+    """
+
+    # Log base 10 value of maximum adjacent comment length.
+    _N = 10
+
+    text = models.TextField()
+    created_at = models.DateTimeField(auto_now_add=True)
+    modified_at = models.DateTimeField(auto_now=True)
+    author = models.ForeignKey(
+        get_user_model(), on_delete=models.SET_NULL, null=True, related_name="comments"
+    )
+    upvotes = models.ManyToManyField(
+        get_user_model(), related_name="upvotes", help_text="The number of upvotes a comment gets."
+    )
+    downvotes = models.ManyToManyField(
+        get_user_model(),
+        related_name="downvotes",
+        help_text="The number of downvotes a comment gets.",
+    )
+    section = models.ForeignKey(
+        Section,
+        on_delete=models.CASCADE,
+        help_text=dedent(
+            """
+        The section with which a comment is associated. Section was chosen instead of topics for
+        hosting comments because topics are SOFT STATE and are recomputed regularly.
+        """
+        ),
+        null=True,
+    )
+
+    instructor = models.ForeignKey(
+        Instructor,
+        on_delete=models.SET_NULL,
+        help_text=dedent(
+            """
+        The instructor with which a comment is associated. Instructor was chosen instead of topics
+        for hosting comments because topics are SOFT STATE and are recomputed regularly.
+        """
+        ),
+        null=True,
+    )
+
+    base = models.ForeignKey(
+        "self",
+        on_delete=models.SET_NULL,  # redundant due to special deletion conditions
+        null=True,
+    )
+    parent = models.ForeignKey(
+        "self", on_delete=models.SET_NULL, null=True, related_name="children"  # similarly redundant
+    )
+    path = models.TextField(db_index=True)
+
+    def level(self):
+        return len(self.path.split("."))
+
+    def delete(self, **kwargs):
+        if Comment.objects.filter(parent_id=self).exists():
+            self.text = "This comment has been removed."
+            self.upvotes.clear()
+            self.downvotes.clear()
+            self.author = None
+            self.save()
+        else:
+            super().delete(**kwargs)
+
+    def __str__(self):
+        return f"{self.author}: {self.text}"

backend/courses/serializers.py

@@ -5,6 +5,7 @@
 
 from courses.models import (
     Attribute,
+    Comment,
     Course,
     Friendship,
     Instructor,
@@ -475,3 +476,83 @@ class FriendshipRequestSerializer(serializers.Serializer):
 
     def to_representation(self, instance):
         return super().to_representation(instance)
+
+
+class CommentSerializer(serializers.ModelSerializer):
+    author_name = serializers.CharField(source="author.username", read_only=True)
+    votes = serializers.SerializerMethodField()
+    section = serializers.CharField(source="section.full_code", read_only=True)
+    base = serializers.SerializerMethodField()
+    parent = serializers.SerializerMethodField()
+    semester = serializers.CharField(source="section.course.semester", read_only=True)
+
+    def get_votes(self, obj):
+        return len(obj.upvotes.values_list("id")) - len(obj.downvotes.values_list("id"))
+
+    def get_base(self, obj):
+        if obj.base is None:
+            return None
+        return obj.base.id
+
+    def get_parent(self, obj):
+        if obj.parent is None:
+            return None
+        return obj.parent.id
+
+    class Meta:
+        model = Comment
+        fields = [
+            "id",
+            "text",
+            "created_at",
+            "modified_at",
+            "author_name",
+            "votes",
+            "section",
+            "base",
+            "parent",
+            "path",
+            "semester"
+        ]
+
+
+class CommentListSerializer(serializers.ModelSerializer):
+    author_name = serializers.CharField(source="author.username", read_only=True)
+    votes = serializers.SerializerMethodField()
+    section = serializers.CharField(source="section.full_code", read_only=True)
+    base = serializers.SerializerMethodField()
+    parent = serializers.SerializerMethodField()
+    user_upvoted = serializers.BooleanField()
+    user_downvoted = serializers.BooleanField()
+    semester = serializers.CharField(source="section.course.semester", read_only=True)
+
+    def get_votes(self, obj):
+        return len(obj.upvotes.values_list("id")) - len(obj.downvotes.values_list("id"))
+
+    def get_base(self, obj):
+        if obj.base is None:
+            return None
+        return obj.base.id
+
+    def get_parent(self, obj):
+        if obj.parent is None:
+            return None
+        return obj.parent.id
+
+    class Meta:
+        model = Comment
+        fields = [
+            "id",
+            "text",
+            "created_at",
+            "modified_at",
+            "author_name",
+            "votes",
+            "section",
+            "base",
+            "parent",
+            "path",
+            "user_upvoted",
+            "user_downvoted",
+            "semester",
+        ]