Roulette React App

A decentralized roulette game built with React and Solidity, featuring real-time balance updates and blockchain-based betting.

Features

• Real-time Balance Updates: Player and house balances update automatically after transactions
• Blockchain-based Betting: All bets are placed and executed on the blockchain
• Token-based Economy: Uses a custom ERC-20 token (GAME) for betting
• Multiple Bet Types: Supports straight-up bets with 35:1 payouts
• Completion Tracking: Tracks player progress through all wheel numbers

Setup Instructions

Prerequisites

• Node.js (v16 or higher)
• npm or yarn
• MetaMask or similar Web3 wallet

Installation

1. Clone the repository

   git clone <repository-url>cd roulette-react

2. One-command setup (Recommended)

   npm run setup

   This will install dependencies, start the blockchain, deploy contracts, and update addresses automatically.

3. Start the React application

   npm start

Manual Installation (Alternative)

If you prefer to run each step manually:

1. Install dependencies

   npm install

2. Start the local blockchain

   npx hardhat node

3. Initialize the blockchain (in a new terminal)

   npx hardhat run scripts/initializeChain.js --network localhost

4. Update contract addresses (in a new terminal)

   npm run update-addresses

5. Start the React application

   npm start

6. Connect MetaMask

   • Network: Localhost 8545
   • Chain ID: 1337
   • Import one of the test accounts provided by Hardhat

How It Works

Contract Architecture

• MyGameToken.sol: ERC-20 token with 1:100,000 ETH ratio
• RandomnessProvider.sol: Provides random numbers (demo only - not secure for production)
• Roulette.sol: Main game contract handling bets and payouts

Balance Update System

The application now features a robust balance update system:

1. Real-time Updates: Balances refresh automatically when new blocks are mined
2. Transaction Confirmation: UI waits for transaction confirmation before updating
3. Error Handling: Graceful error handling with user feedback
4. Pending Bet Management: Bets are stored on-chain and can be cleared

Betting Flow

1. Place Bet: Click on a betting square to place a bet (requires token approval)
2. Spin: Click the spin button to execute the wager
3. Results: View results and updated balances
4. Payouts: Winnings are automatically transferred to the player

Recent Fixes

Balance Update Issues (Fixed)

• Problem: Player and house balances weren't updating after transactions
• Root Cause:
  • Roulette contract didn't handle actual token transfers
  • Balance updates happened before transaction confirmation
  • House balance only loaded once on component mount
• Solution:
  • Updated Roulette contract to handle real betting with token transfers
  • Implemented proper transaction confirmation flow
  • Added automatic balance refresh on block number changes
  • Fixed HouseInfo component to update with new transactions

Technical Improvements

• Contract Updates: Added placeBet(), clearBets(), and proper payout logic
• Frontend Updates: Implemented transaction confirmation and error handling
• Balance Management: Real-time balance updates with proper timing
• User Experience: Better error messages and loading states

Development

Running Tests

npm test

Contract Deployment

The contracts are automatically deployed during initialization. The deployment order is:

1. MyGameToken
2. RandomnessProvider
3. Roulette (with dependencies)

Environment Variables

The following environment variables can be set (with sensible defaults):

• REACT_APP_FIRST_PLAYER_ADDRESS
• REACT_APP_SECOND_PLAYER_ADDRESS
• REACT_APP_THIRD_PLAYER_ADDRESS
• REACT_APP_HOUSE_ADDRESS
• REACT_APP_TOKEN_CONTRACT_ADDRESS
• REACT_APP_ROULETTE_CONTRACT_ADDRESS

Security Notes

⚠️Important: This is a demo application with the following security considerations:

• Randomness: Uses on-chain randomness that is not secure for production
• No Real Value: Designed for testing and demonstration only
• Local Network: Only intended for local development

For production use, implement:

• Chainlink VRF for secure randomness
• Proper access controls
• Comprehensive testing
• Security audits

Troubleshooting

Common Issues

1. "Insufficient allowance" error

   • Run the initialization script to approve tokens
   • Check that you're using the correct network

2. Balances not updating

   • Ensure MetaMask is connected to localhost:8545
   • Check browser console for errors
   • Verify contracts are deployed correctly

3. Transaction failures

   • Check that you have sufficient tokens
   • Ensure the local blockchain is running
   • Verify contract addresses are correct

Reset Everything

To start fresh:

# Stop all processes# Delete node_modules and reinstall
rm -rf node_modules package-lock.json
npm install
# Restart hardhat node
npx hardhat node
# Reinitialize blockchain
npx hardhat run scripts/initializeChain.js --network localhost
# Start React app
npm start

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Submit a pull request

License

MIT License - see LICENSE file for details.