Refactored evaluation process for improved efficiency:

- Initial response set to null; Frontend now generates a list of anticipated stats;
- Background evaluation dynamically updates DB upon completion;
- Frontend actively monitors and finalizes upon stat evaluation completion.

src/pages/api/evaluate/interactiveSpeaking.ts

@@ -2,12 +2,16 @@
 import type {NextApiRequest, NextApiResponse} from "next";
 import {withIronSessionApiRoute} from "iron-session/next";
 import {sessionOptions} from "@/lib/session";
-import axios from "axios";
+import axios, {AxiosResponse} from "axios";
 import formidable from "formidable-serverless";
 import {ref, uploadBytes} from "firebase/storage";
 import fs from "fs";
-import {storage} from "@/firebase";
+import {app, storage} from "@/firebase";
+import {doc, getDoc, getFirestore, setDoc} from "firebase/firestore";
+import {Stat} from "@/interfaces/user";
+import {speakingReverseMarking} from "@/utils/score";
 
+const db = getFirestore(app);
 export default withIronSessionApiRoute(handler, sessionOptions);
 
 async function handler(req: NextApiRequest, res: NextApiResponse) {
@@ -36,20 +40,41 @@ async function handler(req: NextApiRequest, res: NextApiResponse) {
 			}),
 		);
 
-		const backendRequest = await axios.post(
-			`${process.env.BACKEND_URL}/speaking_task_3`,
-			{answers: uploadingAudios},
+		res.status(200).json(null);
+
+		console.log("🌱 - Still processing");
+		const backendRequest = await evaluate({answers: uploadingAudios});
+		console.log("🌱 - Process complete");
+
+		const correspondingStat = (await getDoc(doc(db, "stats", fields.id))).data() as Stat;
+		const solutions = correspondingStat.solutions.map((x) => ({...x, evaluation: backendRequest.data, solution: uploadingAudios}));
+		await setDoc(
+			doc(db, "stats", fields.id),
 			{
-				headers: {
-					Authorization: `Bearer ${process.env.BACKEND_JWT}`,
+				solutions,
+				score: {
+					correct: speakingReverseMarking[backendRequest.data.overall],
+					missing: 0,
+					total: 100,
 				},
 			},
+			{merge: true},
 		);
-
-		res.status(200).json({...backendRequest.data, answer: uploadingAudios});
+		console.log("🌱 - Updated the DB");
 	});
 }
 
+async function evaluate(body: {answers: object[]}): Promise<AxiosResponse> {
+	const backendRequest = await axios.post(`${process.env.BACKEND_URL}/speaking_task_3`, body, {
+		headers: {
+			Authorization: `Bearer ${process.env.BACKEND_JWT}`,
+		},
+	});
+
+	if (typeof backendRequest.data === "string") return evaluate(body);
+	return backendRequest;
+}
+
 export const config = {
 	api: {
 		bodyParser: false,