🎲 Game Of Chance

Overview | Quickstart | Documentation

This project implements a decentralized lottery system using Chainlink VRF (Verifiable Random Function) for randomness and Chainlink Price Feeds to ensure the lottery entry is pegged to a minimum USD value. Participants can fund the lottery, and a random winner is selected after a specified duration.

⚙️ Built using Foundry, Scaffold-ETH2, Chainlink VRF, and Chainlink Price Feeds.

• 🎰 Randomness with Chainlink VRF: Guarantees a verifiably random lottery outcome.
• 💲 USD Pricing with Chainlink Price Feeds: Ensures participants contribute a minimum amount in USD, regardless of ETH price volatility.
• 🔄 Automatic Lottery Reset: After every round, the lottery resets, allowing for continuous operation.
• 🔐 Safe Fund Distribution: Winnings are automatically sent to the lottery winner securely.

Requirements

Before you begin, you need to install the following tools:

• Node (>= v18.17)
• Yarn
• Foundry
• Git

Quickstart

To get started with the Lottery Smart Contract, follow the steps below:

1. Install Dependencies

If you haven't installed dependencies already:

```bash yarn install ```

2. Run a Local Ethereum Network

In the first terminal, run a local Ethereum network:

```bash yarn chain ```

This starts a local blockchain using Foundry. You can customize the network configuration in foundry.toml.

3. Deploy the Lottery Contract

In the second terminal, deploy the contract:

```bash yarn deploy ```

This deploys the Lottery.sol contract to the local network. The contract can be modified in contracts/.

4. Start the Frontend

In the third terminal, start the Next.js app:

```bash yarn start ```

Visit your app at http://localhost:3000 to interact with the lottery contract. You can monitor the contract's state and interactions via the web UI.

Key Features

• Fund the Lottery: Participants can enter by sending a minimum amount of ETH, pegged to a USD value through Chainlink Price Feeds.
• End the Lottery: Automatically ends after 3 minutes and picks a winner using Chainlink VRF.
• Distribute Winnings: The smart contract transfers the entire lottery balance to the selected winner.

Contract Details

Lottery.sol

The primary contract of the system, Lottery.sol, manages:

• Funding: Users send ETH to enter the lottery.
• Randomness: Uses Chainlink VRF to ensure the winner is selected randomly.
• Payouts: Distributes the lottery funds to the winner automatically.

PriceConverter.sol

A utility library, PriceConverter.sol, converts ETH amounts to USD using Chainlink Price Feeds. This ensures that all participants meet the minimum entry requirement in USD.

Deploy.s.sol

The Deploy.s.sol script is used to deploy the Lottery contract. It configures the lottery with Chainlink Price Feeds and VRF settings, handling both local and live environments.

Running Tests

You can run the tests using Foundry’s test framework:

```bash forge test ```

The tests include mocks for the Chainlink Price Feeds and VRF for local testing.

Deployment to Sepolia Testnet

To deploy the contracts to Sepolia, set up your .env file with the required variables:

```bash SEPOLIA_RPC_URL=https://eth-sepolia.g.alchemy.com/v2/YOUR_ALCHEMY_KEY PRIVATE_KEY=YOUR_PRIVATE_KEY ETHERSCAN_API_KEY=YOUR_ETHERSCAN_API_KEY ```

Then deploy:

```bash forge script script/Deploy.s.sol --rpc-url $SEPOLIA_RPC_URL --private-key $PRIVATE_KEY --broadcast --verify --etherscan-api-key $ETHERSCAN_API_KEY ```

Documentation

For a detailed explanation of how the lottery works, as well as customization options, visit the project documentation:

• Contract Documentation: Lottery.sol
• Price Converter: PriceConverter.sol
• Chainlink VRF: VRF Consumer Guide

Check out Scaffold-ETH’s documentation for more on how this project integrates with the Scaffold-ETH2 framework.