feat: enhance Quiz schema with schedule-based quiz retrieval and error handling

- Added logic to require 'scheduleId' for customers when retrieving quizzes, ensuring proper association with schedules.
- Implemented error handling for missing 'scheduleId' and non-existent schedules, improving robustness and user feedback.
- Refactored quiz retrieval logic for customers and center mentors to utilize the correct center mentor ID from the schedule, enhancing data integrity.
- Updated comments for clarity regarding the quiz selection process based on user roles.

src/Quiz/quiz.schema.ts

@@ -163,33 +163,50 @@ export class QuizSchema extends PothosSchema {
           if (!ctx.http.me) {
             throw new Error('Unauthorized')
           }
-          // use case 1: center mentor or center owner
-          if (ctx.http.me.role === Role.CENTER_MENTOR || ctx.http.me.role === Role.CENTER_OWNER) {
-            const centerMentor = await this.prisma.centerMentor.findUnique({
-              where: { mentorId: ctx.http.me.id },
-            })
+          // use case 1: customer
+          if (ctx.http.me.role === Role.CUSTOMER) {
             // 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) {
+            if (!args.scheduleId) {
+              throw new Error('Schedule ID is required')
+            }
+            // get schedule from scheduleId
+            const schedule = await this.prisma.schedule.findUnique({
+              where: { id: args.scheduleId },
+              include: {
+                managedService: true,
+              },
+            })
+            if (!schedule) {
+              throw new Error('Schedule not found')
+            }
+            // get centerMentorId from schedule
+            const centerMentorId = schedule.managedService.mentorId
+            if (!centerMentorId) {
               throw new Error('Center mentor not found')
             }
             const quizzes = await this.prisma.quiz.findMany({
               ...query,
               where: {
                 serviceId: args.serviceId,
-                centerMentorId: centerMentor.mentorId,
+                centerMentorId: centerMentorId,
               },
             })
-            // get amount of quizzes using nrOfQuestions and random index based on random
-            const randomIndex = Math.floor(random * quizzes.length)
-            return quizzes.slice(randomIndex, randomIndex + (quizzes[0].nrOfQuestions ?? 1))
+            // get amount of questions using nrOfQuestions and random index based on random
+            const randomIndex = Math.floor(random * (quizzes[0]?.nrOfQuestions ?? 1))
+            return quizzes.slice(randomIndex, randomIndex + (quizzes[0]?.nrOfQuestions ?? 1))
           }
 
-          // use case 2: Customer
-          if (ctx.http.me.role === Role.CUSTOMER) {
-            // if scheduleId is provided, return quizzes for the schedule
+          // use case 2: center mentor or center owner
+          if (ctx.http.me.role === Role.CENTER_MENTOR || ctx.http.me.role === Role.CENTER_OWNER) {
+            const centerMentor = await this.prisma.centerMentor.findUnique({
+              where: { mentorId: ctx.http.me.id },
+            })
+            if (!centerMentor) {
+              throw new Error('Center mentor not found')
+            }
             if (args.scheduleId) {
               const schedule = await this.prisma.schedule.findUnique({
                 where: { id: args.scheduleId },
@@ -201,6 +218,7 @@ export class QuizSchema extends PothosSchema {
                 ...query,
                 where: {
                   serviceId: args.serviceId,
+                  centerMentorId: centerMentor.mentorId,
                 },
               })
             }