From caa9e46694717bacabb2543fca9b062a9155303e Mon Sep 17 00:00:00 2001
From: Jweng88 <108978684+Jweng88@users.noreply.github.com>
Date: Wed, 11 Sep 2024 16:42:05 +0800
Subject: [PATCH] Add question id to question schema with auto-increment

---
 question-service/src/model/counter-model.ts  | 16 ++++++++++++++++
 question-service/src/model/question-model.ts | 19 +++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 question-service/src/model/counter-model.ts

diff --git a/question-service/src/model/counter-model.ts b/question-service/src/model/counter-model.ts
new file mode 100644
index 0000000000..4696e82faf
--- /dev/null
+++ b/question-service/src/model/counter-model.ts
@@ -0,0 +1,16 @@
+import mongoose from "mongoose";
+
+const counterSchema = new mongoose.Schema({
+  _id: {
+    type: String,
+    required: true,
+  },
+  seq: {
+    type: Number,
+    default: 0,
+  },
+});
+
+const Counter = mongoose.model("Counter", counterSchema);
+
+export default Counter;
diff --git a/question-service/src/model/question-model.ts b/question-service/src/model/question-model.ts
index 72d5d07209..2524f86b61 100644
--- a/question-service/src/model/question-model.ts
+++ b/question-service/src/model/question-model.ts
@@ -7,9 +7,11 @@
 //   export const users: User[] = [];
 
 import mongoose, { Schema, Document } from "mongoose";
+import Counter from "./counter-model";
 
 // Define the schema for a Question
 interface QuestionDocument extends Document {
+  question_id: number;
   title: string;
   description: string;
   category: string;
@@ -17,10 +19,27 @@ interface QuestionDocument extends Document {
 }
 
 const questionSchema: Schema = new Schema({
+  question_id: { type: Number, unique: true },
   title: { type: String, required: true },
   description: { type: String, required: true },
   category: { type: String, required: true },
   complexity: { type: String, required: true },
 });
 
+// Middleware to auto-increment the question_id before saving
+questionSchema.pre("save", async function (next) {
+  const question = this as any;
+
+  if (question.isNew) {
+    const counter = await Counter.findByIdAndUpdate(
+      { _id: "questionId" },
+      { $inc: { seq: 1 } },
+      { new: true, upsert: true }
+    );
+    question.question_id = counter?.seq;
+  }
+
+  next();
+});
+
 export default mongoose.model<QuestionDocument>("Question", questionSchema);