From 30f56747f7906b10def4b313221d040c2142f6e4 Mon Sep 17 00:00:00 2001
From: Ly Tuan Kiet <lyhung998877@gmail.com>
Date: Mon, 9 Dec 2024 20:07:22 +0700
Subject: [PATCH] feat: enhance Quiz schema with random quiz retrieval and
 amount argument

- Added a new 'amount' argument to the quiz retrieval query, allowing users to specify the number of quizzes to return.
- Implemented a seeded randomization mechanism to select quizzes based on the user's ID, improving the randomness of quiz selection.
- Refactored the quiz retrieval logic to utilize the new randomization and amount features, enhancing user experience and engagement.
---
 src/Quiz/quiz.schema.ts | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/Quiz/quiz.schema.ts b/src/Quiz/quiz.schema.ts
index 5c2c2fb..70a7ef5 100644
--- a/src/Quiz/quiz.schema.ts
+++ b/src/Quiz/quiz.schema.ts
@@ -1,10 +1,10 @@
+import crypto from 'crypto'
 import { Inject, Injectable } from '@nestjs/common'
 import { AnswerType, Role } from '@prisma/client'
 import { QuestionType } from '@prisma/client'
 import { Pothos, PothosRef, PothosSchema, SchemaBuilderToken } from '@smatch-corp/nestjs-pothos'
 import { Builder } from '../Graphql/graphql.builder'
 import { PrismaService } from '../Prisma/prisma.service'
-
 @Injectable()
 export class QuizSchema extends PothosSchema {
   constructor(
@@ -155,6 +155,10 @@ export class QuizSchema extends PothosSchema {
             type: 'String',
             required: false,
           }),
+          amount: t.arg({
+            type: 'Int',
+            required: false,
+          }),
         },
         resolve: async (query, _root, args, ctx, _info) => {
           if (ctx.isSubscription) {
@@ -168,16 +172,23 @@ export class QuizSchema extends PothosSchema {
             const centerMentor = await this.prisma.centerMentor.findUnique({
               where: { mentorId: ctx.http.me.id },
             })
+            // using pseudo random to get amount of quizzes based on userid as seed
+            const random = getRandomWithSeed(
+              parseInt(crypto.createHash('sha256').update(ctx.http.me.id).digest('hex'), 16),
+            )
             if (!centerMentor) {
               throw new Error('Center mentor not found')
             }
-            return await this.prisma.quiz.findMany({
+            const quizzes = await this.prisma.quiz.findMany({
               ...query,
               where: {
                 serviceId: args.serviceId,
                 centerMentorId: centerMentor.mentorId,
               },
             })
+            // get amount of quizzes using args.amount and random index based on random
+            const randomIndex = Math.floor(random * quizzes.length)
+            return quizzes.slice(randomIndex, randomIndex + (args.amount ?? 1))
           }
 
           // use case 2: Customer
@@ -311,3 +322,12 @@ export class QuizSchema extends PothosSchema {
     }))
   }
 }
+
+function seededRandom(seed: number) {
+  const x = Math.sin(seed) * 10000
+  return x - Math.floor(x)
+}
+
+function getRandomWithSeed(seed: number) {
+  return seededRandom(seed)
+}