add sorting by likes

rating_api/models/db.py

@@ -18,10 +18,12 @@
     String,
     UnaryExpression,
     and_,
+    case,
     desc,
     func,
     nulls_last,
     or_,
+    select,
     true,
 )
 from sqlalchemy.ext.hybrid import hybrid_method, hybrid_property
@@ -186,14 +188,64 @@ def search_by_subject(self, query: str) -> bool:
         return and_(Comment.review_status == ReviewStatus.APPROVED, func.lower(Comment.subject).contains(query))
 
     @hybrid_property
-    def like_count(self) -> int:
-        """Python access to like count"""
-        return sum(1 for like in self.reactions if like.reaction == 'like')
+    def like_count(self):
+        """Python доступ к числу лайков"""
+        return sum(1 for reaction in self.reactions if reaction.reaction == Reaction.LIKE)
+
+    @like_count.expression
+    def like_count(cls):
+        """SQL выражение для подсчета лайков"""
+        return (
+            select(func.count(CommentReaction.uuid))
+            .where(and_(CommentReaction.comment_uuid == cls.uuid, CommentReaction.reaction == Reaction.LIKE))
+            .label('like_count')
+        )
 
     @hybrid_property
-    def dislike_count(self) -> int:
-        """Python access to dislike count"""
-        return sum(1 for like in self.reactions if like.reaction == 'dislike')
+    def dislike_count(self):
+        """Python доступ к числу дизлайков"""
+        return sum(1 for reaction in self.reactions if reaction.reaction == Reaction.DISLIKE)
+
+    @dislike_count.expression
+    def dislike_count(cls):
+        """SQL выражение для подсчета дизлайков"""
+        return (
+            select(func.count(CommentReaction.uuid))
+            .where(and_(CommentReaction.comment_uuid == cls.uuid, CommentReaction.reaction == Reaction.DISLIKE))
+            .label('dislike_count')
+        )
+
+    @hybrid_property
+    def like_dislike_diff(self):
+        """Python доступ к разнице лайков и дизлайков"""
+        if hasattr(self, '_like_dislike_diff'):
+            return self._like_dislike_diff
+        return self.like_count - self.dislike_count
+
+    @like_dislike_diff.expression
+    def like_dislike_diff(cls):
+        """SQL выражение для вычисления разницы лайков/дизлайков"""
+        return (
+            select(
+                func.sum(
+                    case(
+                        (CommentReaction.reaction == Reaction.LIKE, 1),
+                        (CommentReaction.reaction == Reaction.DISLIKE, -1),
+                        else_=0,
+                    )
+                )
+            )
+            .where(CommentReaction.comment_uuid == cls.uuid)
+            .label('like_dislike_diff')
+        )
+
+    @hybrid_method
+    def order_by_like_diff(cls, asc_order: bool = False):
+        """Метод для сортировки по разнице лайков/дизлайков"""
+        if asc_order:
+            return cls.like_dislike_diff.asc()
+        else:
+            return cls.like_dislike_diff.desc()
 
 
 class LecturerUserComment(BaseDbModel):

rating_api/routes/comment.py

@@ -174,7 +174,7 @@ async def get_comments(
     user_id: int | None = None,
     subject: str | None = None,
     order_by: str = Query(
-        enum=["create_ts", "mark_kindness", "mark_freebie", "mark_clarity", "mark_general"],
+        enum=["create_ts", "mark_kindness", "mark_freebie", "mark_clarity", "mark_general", "like_diff"],
         default="create_ts",
     ),
     unreviewed: bool = False,
@@ -190,9 +190,10 @@ async def get_comments(
      Если без смещения возвращается комментарий с условным номером N,
      то при значении offset = X будет возвращаться комментарий с номером N + X
 
-    `order_by` - возможные значения `"create_ts", "mark_kindness", "mark_freebie", "mark_clarity", "mark_general"`.
-     Если передано `'create_ts'` - возвращается список комментариев отсортированных по времени
-     Если передано `'mark_...'` - возвращается список комментариев отсортированных по конкретной оценке
+    `order_by` - возможные значения `"create_ts", "mark_kindness", "mark_freebie", "mark_clarity", "mark_general", "like_diff"`.
+     Если передано `'create_ts'` - возвращается список комментариев, отсортированных по времени
+     Если передано `'mark_...'` - возвращается список комментариев, отсортированных по конкретной оценке
+     Если передано `'like_diff'` - возвращается список комментариев, отсортированных по разнице лайков и дизлайков
 
      `lecturer_id` - вернет все комментарии для преподавателя с конкретным id, по дефолту возвращает вообще все аппрувнутые комментарии.
 
@@ -210,7 +211,11 @@ async def get_comments(
         .order_by(
             Comment.order_by_mark(order_by, asc_order)
             if "mark" in order_by
-            else Comment.order_by_create_ts(order_by, asc_order)
+            else (
+                Comment.order_by_like_diff(asc_order)
+                if order_by == "like_diff"
+                else Comment.order_by_create_ts(order_by, asc_order)
+            )
         )
     )
     comments = comments_query.limit(limit).offset(offset).all()

tests/test_routes/test_comment.py

@@ -5,7 +5,7 @@
 import pytest
 from starlette import status
 
-from rating_api.models import Comment, LecturerUserComment, ReviewStatus
+from rating_api.models import Comment, CommentReaction, LecturerUserComment, Reaction, ReviewStatus
 from rating_api.settings import get_settings
 
 
@@ -205,6 +205,116 @@ def test_get_comment(client, comment):
     assert response.status_code == status.HTTP_404_NOT_FOUND
 
 
+@pytest.fixture
+def comments_with_likes(client, dbsession, lecturers):
+    """
+    Создает несколько комментариев с разным количеством лайков/дизлайков
+    """
+    comments = []
+
+    user_id = 9999
+
+    comment_data = [
+        {
+            "user_id": user_id,
+            "lecturer_id": lecturers[0].id,
+            "subject": "test_subject",
+            "text": "Comment with many likes",
+            "mark_kindness": 1,
+            "mark_freebie": 0,
+            "mark_clarity": 0,
+            "review_status": ReviewStatus.APPROVED,
+        },
+        {
+            "user_id": user_id,
+            "lecturer_id": lecturers[0].id,
+            "subject": "test_subject",
+            "text": "Comment with many dislikes",
+            "mark_kindness": 1,
+            "mark_freebie": 0,
+            "mark_clarity": 0,
+            "review_status": ReviewStatus.APPROVED,
+        },
+        {
+            "user_id": user_id,
+            "lecturer_id": lecturers[0].id,
+            "subject": "test_subject",
+            "text": "Comment with balanced reactions",
+            "mark_kindness": 1,
+            "mark_freebie": 0,
+            "mark_clarity": 0,
+            "review_status": ReviewStatus.APPROVED,
+        },
+    ]
+
+    for data in comment_data:
+        comment = Comment(**data)
+        dbsession.add(comment)
+        comments.append(comment)
+
+    dbsession.commit()
+
+    for _ in range(10):
+        reaction = CommentReaction(comment_uuid=comments[0].uuid, user_id=user_id, reaction=Reaction.LIKE)
+        dbsession.add(reaction)
+    for _ in range(2):
+        reaction = CommentReaction(comment_uuid=comments[0].uuid, user_id=user_id, reaction=Reaction.DISLIKE)
+        dbsession.add(reaction)
+
+    for _ in range(3):
+        reaction = CommentReaction(comment_uuid=comments[1].uuid, user_id=user_id, reaction=Reaction.LIKE)
+        dbsession.add(reaction)
+    for _ in range(8):
+        reaction = CommentReaction(comment_uuid=comments[1].uuid, user_id=user_id, reaction=Reaction.DISLIKE)
+        dbsession.add(reaction)
+
+    for _ in range(5):
+        reaction = CommentReaction(comment_uuid=comments[2].uuid, user_id=user_id, reaction=Reaction.LIKE)
+        dbsession.add(reaction)
+    for _ in range(5):
+        reaction = CommentReaction(comment_uuid=comments[2].uuid, user_id=user_id, reaction=Reaction.DISLIKE)
+        dbsession.add(reaction)
+
+    dbsession.commit()
+
+    for comment in comments:
+        dbsession.refresh(comment)
+
+    return comments
+
+
+@pytest.mark.parametrize(
+    'order_by, asc_order',
+    [
+        ('like_diff', False),
+        ('like_diff', True),
+    ],
+)
+def test_comments_sort_by_like_diff(client, comments_with_likes, order_by, asc_order):
+    """
+    Тестирует сортировку комментариев по разнице лайков (like_diff)
+    """
+    params = {"order_by": order_by, "asc_order": asc_order, "limit": 10}
+
+    response = client.get('/comment', params=params)
+    assert response.status_code == status.HTTP_200_OK
+
+    json_response = response.json()
+    returned_comments = json_response["comments"]
+
+    if order_by == 'like_diff':
+        if asc_order:
+            for i in range(len(returned_comments) - 1):
+                current_like_diff = returned_comments[i]["like_count"] - returned_comments[i]["dislike_count"]
+                next_like_diff = returned_comments[i + 1]["like_count"] - returned_comments[i + 1]["dislike_count"]
+                assert current_like_diff <= next_like_diff
+        else:
+            for i in range(len(returned_comments) - 1):
+                current_like_diff = returned_comments[i]["like_count"] - returned_comments[i]["dislike_count"]
+                next_like_diff = returned_comments[i + 1]["like_count"] - returned_comments[i + 1]["dislike_count"]
+                assert current_like_diff >= next_like_diff
+
+
 @pytest.mark.parametrize(
     'lecturer_n,response_status',
     [(0, status.HTTP_200_OK), (1, status.HTTP_200_OK), (2, status.HTTP_200_OK), (3, status.HTTP_404_NOT_FOUND)],