🧠 NotAI — AI Chat, Code Execution & Contest Arena

A full-stack web app that merges AI-powered chat, live code execution, and AI-generated coding contests, built using React, TypeScript, Node.js, and MongoDB.

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⚡ Overview

NotAI lets users chat with Google Gemini AI, manage multiple conversations, execute code in real time across popular programming languages, and compete in AI-generated coding contests — all in one clean, responsive interface.

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✨ Features

💬 Chat Interface

• Google Gemini AI integration
• Real-time streaming responses
• Persistent chat history (MongoDB)
• Multiple conversation sessions

💻 Code Assistant

• Supports JavaScript, Python, Java, C++
• Judge0 API integration for safe cloud execution
• Monaco Editor (VS Code-like experience)
• Syntax highlighting and error reporting

🏆 Contest Arena

• AI-Generated DSA Problems — Unique coding challenges generated by Gemini AI
• Three Difficulty Levels — Beginner, Intermediate, and Expert
• Multiple Topics — Arrays, Strings, Trees, Graphs, Dynamic Programming, and more
• Live Code Execution — Test your solutions with example and hidden test cases
• Progress Tracking — Track solved problems and success rate
• Leaderboard — Compete with other users and see rankings by difficulty
• Submission History — Review all your previous attempts and solutions
• Smart Problem Generation — Never get the same problem twice for a topic

🔐 Authentication

• JWT-based user sessions
• Encrypted passwords (bcrypt)
• Protected API routes

📱 Responsive Design

• Mobile-first layout
• PWA-ready for installable experience
• Smooth animations and dark/light mode

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🧩 Project Structure

Frontend — React + TypeScript

frontend/
├── src/
│   ├── components/   # Chat, CodeEditor, Auth, Contest, Leaderboard, etc.
│   ├── context/      # Auth, Chat & Contest state
│   ├── services/     # API integration
│   └── types/        # TypeScript definitions

Backend — Node.js + Express

backend/
├── models/       # MongoDB schemas (User, Chat, Submission)
├── routes/       # Auth, Chat & Contest APIs
├── middleware/   # JWT verification
└── server.js     # Entry point

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🛠️ Tech Stack

Layer	Technologies
Frontend	React, TypeScript, Tailwind CSS, Vite, Monaco Editor
Backend	Node.js, Express.js, Mongoose
Database	MongoDB
External APIs	Google Gemini AI, Judge0 API
Auth	JWT, bcrypt

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🧱 Database Models

User

{
  username: String,
  email: String,
  password: String,
  createdAt: Date
}

Chat

{
  user: ObjectId (ref: User),
  title: String,
  messages: [{ role: String, content: String, timestamp: Date }],
  createdAt: Date
}

Submission (Contest)

{
  user: ObjectId (ref: User),
  problemTitle: String,
  problemDescription: String,
  difficulty: String,
  topic: String,
  language: String,
  code: String,
  solved: Boolean,
  attempts: Number,
  testCases: Array,
  lastAttemptedAt: Date
}

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🏆 Contest Arena — How It Works

Starting a Contest

1. Select Difficulty — Choose from Beginner, Intermediate, or Expert
2. Pick a Topic — Select from 15+ DSA topics or enter a custom one
3. Choose Language — Python, JavaScript, C++, or Java
4. Generate Problem — AI creates a unique coding challenge

Solving Problems

• Problem Description — Clear problem statement with constraints
• Example Test Cases — Visible test cases to understand the problem
• Code Editor — Monaco editor with syntax highlighting
• Run Code — Test with custom inputs
• Submit — Run against all test cases (including hidden ones)

Tracking Progress

• Dashboard — View your stats (problems solved, attempts, success rate)
• Submission History — Review all past attempts with code
• Leaderboard — See global rankings by difficulty level
• Smart Generation — System remembers solved problems to avoid duplicates

Difficulty Levels

• Beginner — Basic data structures and simple algorithms
• Intermediate — Moderate complexity with multiple concepts
• Expert — Advanced algorithms and complex problem-solving

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🚀 Getting Started

Prerequisites

• Node.js ≥ 16
• MongoDB (local or Atlas)
• Google Gemini API key
• Judge0 API key

Setup

git clone https://github.com/Harsh-sh7/NotAI.git
cd NotAI

Backend

cd backend
npm install
# Add .env
MONGODB_URI=mongodb://localhost:27017/notai
JWT_SECRET=your_jwt_secret
GEMINI_API_KEY=your_gemini_api_key
RAPIDAPI_KEY=your_judge0_api_key
PORT=5001

npm run dev

Frontend

cd ../frontend
npm install
# Add .env
VITE_API_URL=http://localhost:5001
GEMINI_API_KEY=your_gemini_api_key

npm run dev

Then visit http://localhost:3000.

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⚙️ Environment Variables

Variable	Description
MONGODB_URI	MongoDB connection string
JWT_SECRET	JWT encryption key
GEMINI_API_KEY	Google Gemini API key
RAPIDAPI_KEY	Judge0 API key
PORT	Backend port
VITE_API_URL	Frontend API base URL

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🚢 Deployment

Build & Deploy

# Frontend
cd frontend && npm run build

# Backend
cd backend && npm start

Recommended Hosting:

• Frontend → Vercel / Netlify
• Backend → Render / Railway / DigitalOcean
• Database → MongoDB Atlas

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🤝 Contributing

1. Fork the repo
2. Create a branch → git checkout -b feature/new-feature
3. Commit changes → git commit -m "Added new feature"
4. Push → git push origin feature/new-feature
5. Open a Pull Request

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📜 License

This project is licensed under the MIT License — see LICENSE.

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👨‍💻 Author

Harsh Sharma
🔗 GitHub Profile
💡 Project Repo: NotAI

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🙏 Acknowledgments

• Google Gemini AI
• Judge0 API
• React & TypeScript Communities
• Tailwind CSS & Vite
• MongoDB Atlas

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