Merge pull request #140 from CS3219-AY2425S1/fix/bug/update-question-…

…endpoint

Fix duplicate handling in update questions backend

question-service/app/crud/questions.py

@@ -39,14 +39,22 @@ async def delete_question(question_id: str):
 
 async def update_question_by_id(question_id: str, question_data: UpdateQuestionModel):
     existing_question = await question_collection.find_one({"_id": ObjectId(question_id)})
+
     if existing_question is None:
         return None
+
+    update_data = question_data.model_dump(exclude_unset=True)
+
+    # Check if the new title already exists and belongs to another question
+    if "title" in update_data and update_data["title"] != existing_question["title"]:
+        existing_title = await question_collection.find_one({"title": update_data["title"]})
+        if existing_title and str(existing_title["_id"]) != question_id:
+            return "duplicate_title"
 
-    updated_data = {"$set": question_data.model_dump(exclude_unset=True)}
-    if not updated_data["$set"]:
+    if not update_data:
         return existing_question
-    
-    await question_collection.update_one({"_id": ObjectId(question_id)}, updated_data)
+
+    await question_collection.update_one({"_id": ObjectId(question_id)}, {"$set": update_data})
     return await question_collection.find_one({"_id": ObjectId(question_id)})
 
 async def batch_create_questions(questions: List[CreateQuestionModel]):
@@ -62,4 +70,4 @@ async def batch_create_questions(questions: List[CreateQuestionModel]):
 
     result = await question_collection.insert_many(new_questions)
 
-    return {"message": f"{len(result.inserted_ids)} questions added successfully."}
+    return {"message": f"{len(result.inserted_ids)} questions added successfully."}

question-service/app/routers/questions.py

@@ -47,9 +47,13 @@ async def delete(question_id: str):
 @router.put("/{question_id}", response_description="Update question with specified id", response_model=QuestionModel)
 async def update_question(question_id: str, question_data: UpdateQuestionModel):
     updated_question = await update_question_by_id(question_id, question_data)
+
     if updated_question is None:
         raise HTTPException(status_code=404, detail="Question with this id does not exist.")
 
+    if updated_question == "duplicate_title":
+        raise HTTPException(status_code=409, detail="A question with this title already exists.")
+
     return updated_question