SSMU MCQs (Production-Grade Monorepo)

This repository contains a scalable 3-layer system for SSMU MCQs:

• mobile-app/: React Native Android app (student experience).
• backend/: Node.js + Express REST API + MongoDB.
• admin-panel/: React web admin console.

Core Product Coverage

• Google/Gmail login flow (POST /auth/google-login) with JWT session.
• Single-device session policy: new login invalidates previous device session for the same account.
• 90-day subscription activation from verified payment (INR 49).
• Strict learning hierarchy: Course → Subject → Module → Topic → Task Type → MCQs.
• One-question-at-a-time MCQ engine with instant correct/incorrect + explanation.
• Offline-friendly behavior with cached course/content fallback.
• Admin content and import workflow for PDF/DOCX: upload → preview → validate/edit → publish.
• Seeded 6-course structure from the provided university curriculum.

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Project Structure

/backend
  /src
    /config
    /controllers
    /middlewares
    /models
    /routes
    /services
    /seed
    server.js
/mobile-app
  /src
    /components
    /navigation
    /screens
    /services
    /store
    /utils
/admin-panel
  /src
    /pages
    /services

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API Endpoints (Implemented)

Auth

• POST /auth/google-login

User

• GET /user/profile
• GET /user/subscription-status

Payment

• POST /payment/create-order
• POST /payment/verify

Content

• GET /courses
• GET /subjects/:course_id
• GET /modules/:subject_id
• GET /topics/:module_id
• GET /task-types/:topic_id
• GET /mcqs/:task_type_id

MCQ

• POST /mcq/attempt
• GET /mcq/history
• POST /mcq/bookmark
• GET /mcq/bookmarks

Admin

• POST /admin/course
• POST /admin/subject
• POST /admin/module
• POST /admin/topic
• POST /admin/task-type
• POST /admin/mcq
• POST /admin/upload
• GET /admin/users
• GET /admin/payments
• GET /admin/analytics

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Payment & Subscription

• Gateway: Razorpay integration service with secure signature verification.
• UPI settlement target: merchant UPI mrx4u@ybl.
• Subscription starts only after verified payment.
• Duration: exactly 90 days server-side (subscription_start + 90 days).

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Offline Behavior

• Mobile app caches course/content payloads using AsyncStorage.
• If API fails offline, cached content is shown.
• MCQ explanation always uses stored DB explanation; optional enhancement can be layered online later.

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Setup

1) Backend

cd backend
npm install
cp .env.example .env
npm run dev

Create .env with:

PORT=4000
MONGO_URI=mongodb://127.0.0.1:27017/ssmu_mcqs
JWT_SECRET=replace_in_production
JWT_EXPIRY=7d
RAZORPAY_KEY_ID=rzp_xxx
RAZORPAY_KEY_SECRET=xxx
FRONTEND_URL=http://localhost:5173
ADMIN_URL=http://localhost:5174

2) Seed initial 6-course data

cd backend
npm run seed

3) Mobile app (Android)

cd mobile-app
npm install
npm run android

4) Admin panel

cd admin-panel
npm install
npm run dev

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Production Hardening Checklist

• Replace mock Google sign-in in mobile/admin with official SDK + ID token verification.
• Enable webhook-based payment verification in addition to callback signature checks.
• Add refresh tokens, device binding, and secure key vault storage.
• Add pagination/search + audit export in admin panel.
• Add test suites (unit/integration/e2e) and CI pipelines.
• Deploy with Docker/Kubernetes + managed MongoDB + centralized logging.