AI Chat - Local ChatGPT Clone

A fully-featured, locally-hosted AI chat application with multi-user support, powered by Ollama and PostgreSQL.

Features

• 🤖 AI Chat - Powered by Ollama (qwen2.5:1.5b or any model)
• 💬 Multi-User Support - PostgreSQL-based authentication and data isolation
• 🎨 Modern UI - Dark theme with Three.js particle background
• 📝 Markdown Support - Full markdown rendering with code syntax highlighting
• 🔄 Streaming Responses - Real-time AI responses
• 💾 Conversation Management - Create, rename, delete conversations
• 🔐 Secure Authentication - Session-based auth with bcrypt
• 📱 Responsive Design - Works on desktop, tablet, and mobile

Tech Stack

Backend

• Node.js & Express.js
• PostgreSQL
• Ollama (AI models)
• Session-based authentication

Frontend

• React 18 with Vite
• Tailwind CSS
• Zustand (state management)
• Three.js (3D background)
• React Markdown

Prerequisites

• Node.js (v18 or higher)
• PostgreSQL (v14 or higher)
• Ollama (with at least one model installed)

Installing Ollama

Linux/Mac:

curl -fsSL https://ollama.com/install.sh | sh

Windows:

Download from https://ollama.com/download

Pull AI Models

# Recommended lightweight model
ollama pull qwen2.5:1.5b

# Or other models
ollama pull llama2
ollama pull mistral
ollama pull codellama

Verify Ollama is running:

ollama list

Setup Instructions

1. Clone and Install Dependencies

cd think_ai

# Install backend dependencies
cd server
npm install

# Install frontend dependencies
cd ../client
npm install

2. Setup PostgreSQL Database

Create a PostgreSQL database:

# Login to PostgreSQL
psql -U postgres

# Create database
CREATE DATABASE ai_chat;

# Create user (optional)
CREATE USER ai_chat_user WITH PASSWORD 'your_password';
GRANT ALL PRIVILEGES ON DATABASE ai_chat TO ai_chat_user;

# Exit
\q

3. Configure Environment Variables

Create .env file in the server directory:

cd server
cp .env.example .env

Edit .env with your configuration:

# Server Configuration
PORT=3001
NODE_ENV=development

# Database Configuration
DB_HOST=localhost
DB_PORT=5432
DB_NAME=ai_chat
DB_USER=postgres
DB_PASSWORD=your_password_here

# Session Secret (change this!)
SESSION_SECRET=change-this-to-a-random-secret-key

# Ollama Configuration
OLLAMA_BASE_URL=http://localhost:11434
OLLAMA_MODEL=qwen2.5:1.5b

# CORS
CORS_ORIGIN=http://localhost:5173

4. Run Database Migrations

cd server
npm run migrate

You should see:

✓ Users table created
✓ Conversations table created
✓ Messages table created
✓ Generated files table created
✓ Settings table created
✓ Indexes created
✓ Triggers created
✅ All migrations completed successfully

5. Start the Application

Terminal 1 - Backend:

cd server
npm run dev

You should see:

╔═══════════════════════════════════════════╗
║                                           ║
║      AI Chat Server                       ║
║                                           ║
║      Server running on port 3001          ║
║      Environment: development             ║
║                                           ║
╚═══════════════════════════════════════════╝

✓ Database connected successfully
✓ Ollama connected successfully
✓ Available models: qwen2.5:1.5b

Terminal 2 - Frontend:

cd client
npm run dev

You should see:

  VITE v5.0.8  ready in 500 ms

  ➜  Local:   http://localhost:5173/
  ➜  Network: use --host to expose

6. Open the Application

Navigate to http://localhost:5173

Usage

First Time Setup

1. Register an Account

   • Click "Sign Up" on the login page
   • Enter username, email, and password
   • Submit to create your account

2. Start Chatting

   • Click "New Chat" in the sidebar
   • Type your message in the input box
   • Press Enter or click Send
   • Watch the AI respond in real-time!

Features Guide

Conversations

• New Conversation: Click the "New Chat" button
• Rename: Click on the conversation title to edit
• Delete: Hover over a conversation and click the delete icon
• Switch: Click any conversation to load it

Messages

• Send: Type and press Enter (Shift+Enter for new line)
• Regenerate: Click regenerate icon on AI messages
• Copy: Click copy icon to copy message content
• Delete: Click delete icon to remove a message

Keyboard Shortcuts

• Enter - Send message
• Shift + Enter - New line in message
• Ctrl/Cmd + N - New conversation (when implemented)

API Endpoints

Authentication

• POST /api/auth/register - Register new user
• POST /api/auth/login - Login
• POST /api/auth/logout - Logout
• GET /api/auth/me - Get current user

Conversations

• GET /api/conversations - List all conversations
• POST /api/conversations - Create conversation
• GET /api/conversations/:id - Get conversation
• PUT /api/conversations/:id - Update conversation
• DELETE /api/conversations/:id - Delete conversation
• GET /api/conversations/:id/messages - Get messages

Messages

• POST /api/conversations/:id/messages - Send message (supports streaming)
• POST /api/conversations/messages/:id/regenerate - Regenerate message
• DELETE /api/conversations/messages/:id - Delete message

Project Structure

think_ai/
├── client/                   # React frontend
│   ├── src/
│   │   ├── components/      # React components
│   │   │   ├── Chat/       # Chat UI components
│   │   │   ├── Sidebar/    # Sidebar components
│   │   │   └── ThreeBackground/  # 3D background
│   │   ├── store/          # Zustand store
│   │   ├── utils/          # API utilities
│   │   └── App.jsx         # Main app
│   └── package.json
│
├── server/                  # Node.js backend
│   ├── src/
│   │   ├── config/         # Database config
│   │   ├── controllers/    # Route controllers
│   │   ├── services/       # Ollama service
│   │   ├── middleware/     # Express middleware
│   │   ├── routes/         # API routes
│   │   └── server.js       # Main server
│   └── package.json
│
└── storage/                # File storage
    ├── uploads/
    ├── generated/
    └── temp/

Troubleshooting

Database Connection Error

Error: connect ECONNREFUSED

Solution: Make sure PostgreSQL is running:

# Linux/Mac
sudo service postgresql start

# Check status
sudo service postgresql status

Ollama Connection Error

⚠ Ollama not connected

Solution: Start Ollama:

ollama serve

In another terminal, verify models:

ollama list

Port Already in Use

Error: listen EADDRINUSE: address already in use :::3001

Solution: Change the port in server/.env:

PORT=3002

Or kill the process using the port:

# Find process
lsof -i :3001

# Kill it
kill -9 <PID>

CORS Errors

Access to fetch blocked by CORS policy

Solution: Update CORS_ORIGIN in server/.env:

CORS_ORIGIN=http://localhost:5173

ngrok Setup (Optional - External Access)

To access your chat from outside your network:

1. Install ngrok:

# Linux/Mac
brew install ngrok

# Or download from https://ngrok.com/download

2. Start ngrok:

ngrok http 3001

3. Update frontend API calls to use ngrok URL

Performance Tips

• Use a lightweight model for faster responses (qwen2.5:1.5b, phi, etc.)
• Limit conversation history for better performance
• Use SSD storage for PostgreSQL for faster queries
• Allocate enough RAM (4-8GB recommended for model + app)

Development

Backend Development

cd server
npm run dev  # Auto-restart on changes

Frontend Development

cd client
npm run dev  # Hot reload enabled

Database Migrations

To run migrations again:

cd server
npm run migrate

Security Notes

⚠️ Important for Production:

1. Change SESSION_SECRET in .env to a random secure key
2. Use HTTPS in production
3. Set NODE_ENV=production
4. Enable PostgreSQL SSL
5. Use environment-specific .env files
6. Never commit .env files to version control

License

MIT

Contributing

1. Fork the repository
2. Create a feature branch
3. Commit your changes
4. Push to the branch
5. Create a Pull Request

Support

For issues and questions:

• Check the troubleshooting section
• Review Ollama documentation: https://ollama.com
• Check PostgreSQL logs

Roadmap

• File upload support (images, PDFs, documents)
• Voice input/output (TTS/STT)
• Image generation
• Export conversations (PDF, DOCX)
• Advanced settings (temperature, max tokens)
• Model switching in UI
• Conversation search
• Message editing
• Dark/Light theme toggle

Credits

Built with:

• Ollama - Local AI models
• React - UI framework
• Three.js - 3D graphics
• Tailwind CSS - Styling
• Express - Backend framework
• PostgreSQL - Database