🎟️ Full Stack Ticket Booking + Wallet System

📌 Overview

This project is a full-stack ticket booking system with an integrated wallet and admin dashboard. It enables users to reserve and book event seats while ensuring data consistency, concurrency safety, and transactional integrity.

🚀 Features

👤 User Features

• User registration & login (JWT-based authentication)
• Add money to the wallet
• View wallet balance & transaction history
• Browse events
• View seat availability
• Reserve seats (with 5-minute expiry)
• Book seats using your wallet
• View booking history

🛠️ Admin Features

• Admin authentication
• Create/update/delete events
• Bulk create and manage seats
• Monitor bookings
• View wallet transactions
• Cancel bookings
• Process refunds

🧱 System Architecture

1. Backend (Core Logic)

• RESTful APIs
• Business logic implementation
• Concurrency handling
• Transaction management
• Idempotency handling

2. Frontend (UI)

• User interface for booking
• Wallet dashboard
• Admin panel

3. Database

• MongoDB (NoSQL)

• Optimized schema design for:

  • Users
  • Wallet transactions
  • Events
  • Seats
  • Bookings

⚙️ Tech Stack

Backend

• Node.js
• Express.js
• TypeScript

Frontend

• Next.js (Recommended)
• Tailwind CSS
• ShadCN UI
• Redux (State management)

Database

• MongoDB (with Mongoose)

🔐 Authentication Module

Requirements

• User signup & login
• Admin login
• JWT-based authentication

Security Considerations

• Password hashing (bcrypt)
• Token expiration & refresh strategy
• Role-based access control (User/Admin)

💰 Wallet System

Features

• Credit (Add money)
• Debit (Booking payment)
• Transaction history
• Optional: Wallet transfer

Rules

• ❌ No negative balance
• ✅ Use integer values (paise/cents)
• ✅ Maintain transaction ledger

Data Model (Concept)

{
  userId: ObjectId,
  balance: number,
  transactions: [
    {
      type: "credit" | "debit",
      amount: number,
      status: "success" | "failed",
      referenceId: string
    }
  ]
}

🎫 Event & Seat Booking System

Features

• List events
• View seat availability
• Reserve seats
• Book seats

🪑 Seat States

AVAILABLE → RESERVED → BOOKED

⏳ Reservation Rules

• Seats are locked for 5 minutes
• Expired reservations are auto-released

💳 Booking Flow

1. Reserve seats
2. Validate reservation
3. Deduct wallet balance
4. Confirm booking

⚠️ Constraints

• Atomic operations (all-or-nothing)
• No double booking
• No double spending

📜 History Module

Users can view:

• Booking history
• Wallet transaction history

🧑‍💼 Admin Dashboard

Event Management

• Create/update/delete events

Seat Management

• Bulk seat creation
• View seat states

Booking Monitoring

• View all bookings

• Filter by:

  • User
  • Event
  • Status

Wallet Monitoring

• View all transactions

Refund & Cancellation

• Cancel booking
• Refund wallet

⚠️ Critical Requirements

⚔️ Concurrency Handling

• Prevent double booking
• Prevent race conditions in wallet deduction

🔁 Idempotency

• APIs must be retry-safe
• Prevent duplicate booking/payment

⏳ Expiry Handling

• Reservation timeout (5 minutes)
• Auto-release seats

💥 Atomicity

• Booking + payment must succeed or fail together

🧪 Edge Cases to Handle

• Parallel booking requests for the same seat
• Wallet race conditions
• Expired reservations during payment
• Duplicate API requests
• Partial failures in booking flow

🛠️ Setup Instructions

Clone Repository

mkdir project
git clone <repo-url>
cd project

Install node modules

npm install

Deployment

Start the app locally in your system (http://localhost:3000)

npm run dev

Create a build of the application

npm run build

To deploy this project, run

  npm run start

🧠 Design Decisions

• MongoDB Transactions for atomic booking & payment
• Optimistic/Pessimistic locking for seat reservation
• Separate Wallet Ledger for auditability
• Reservation expiry via TTL / cron job
• Idempotency keys for payment APIs

📈 Future Improvements

• Payment gateway integration
• WebSockets for real-time seat updates