Lottery - A Decentralized Raffle System

Decentralized Raffle System

Decentralized Raffle is a smart contract for a provably fair lottery system on Ethereum. Users enter by paying an entrance fee, and a winner is selected automatically using Chainlink VRF for random number generation and Chainlink Automation for execution. The contract handles entry, state management, randomness requests, and prize distribution. A Next.js frontend provides an interface for connecting wallets, entering raffles, viewing players, and triggering upkeep.

Features

• Entrance with ETH payment and player tracking.
• Time-based raffle intervals with automated winner selection.
• Cryptographic randomness via Chainlink VRF v2.5.
• Prize transfer to winner with error handling.
• View functions for fee, players, and recent winner.
• Frontend with wallet integration, transaction handling, and real-time status updates.
• Support for Sepolia testnet and local anvil network.
• Mock contracts for local testing.

Setup

Contracts (Foundry)

1. Navigate to the contracts directory:

   cd contracts
   

2. Install dependencies:

   forge install
   

3. Create a .env file in the contracts directory and add the following variables:

   SEPOLIA_RPC_URL=your_sepolia_rpc_url
   ETHERSCAN_API_KEY=your_etherscan_api_key
   PRIVATE_KEY=your_private_key
   

4. Compile the contract:

   forge build
   

5. Run tests:

   forge test
   

6. Deploy to Sepolia:

   make deploy-sepolia
   

7. Create and fund VRF subscription:

   make createSubscription
   make fundSubscription
   

8. Add consumer:

   make addConsumer
   

Frontend (Next.js)

1. Navigate to the frontend directory:

   cd frontend
   

2. Install dependencies:

   npm install
   

3. Create a .env.local file in the frontend directory and add the following variables:

   NEXT_PUBLIC_SEPOLIA_RPC_URL=your_sepolia_rpc_url
   NEXT_PUBLIC_RAFFLE_ADDRESS=your_deployed_raffle_address
   NEXT_PUBLIC_GITHUB_REPO_URL=your_github_repo_url
   

4. Run the development server:

   npm run dev
   

5. Open http://localhost:3000 in your browser.

For production builds:

npm run build
npm start

File Structure

shaah1d-lottery-solidity/
├── contracts/
│   ├── README.md
│   ├── foundry.toml
│   ├── Makefile
│   ├── script/
│   │   ├── DeployRaffle.s.sol
│   │   ├── HelperConfig.s.sol
│   │   └── Interactions.s.sol
│   ├── src/
│   │   └── Raffle.sol
│   ├── test/
│   │   ├── mocks/
│   │   │   └── LinkToken.sol
│   │   └── unit/
│   │       └── RaffleTest.t.sol
│   └── .github/
│       └── workflows/
│           └── test.yml
└── frontend/
    ├── README.md
    ├── components.json
    ├── eslint.config.mjs
    ├── next.config.ts
    ├── package.json
    ├── postcss.config.mjs
    ├── tailwind.config.js
    ├── tsconfig.json
    ├── abi/
    │   └── Raffle.json
    └── src/
        ├── app/
        │   ├── globals.css
        │   ├── layout.tsx
        │   ├── page.tsx
        │   └── raffle/
        │       └── how-it-works/
        │           └── page.tsx
        ├── components/
        │   ├── advanced-panel.tsx
        │   ├── brand-header.tsx
        │   ├── info-tile.tsx
        │   ├── page.tsx
        │   ├── players-panel.tsx
        │   ├── raffle-controls.tsx
        │   ├── status-panel.tsx
        │   └── ui/
        │       ├── badge.tsx
        │       ├── button.tsx
        │       ├── card.tsx
        │       ├── input.tsx
        │       ├── label.tsx
        │       └── scroll-area.tsx
        ├── hooks/
        │   └── use-raffle.ts
        └── lib/
            ├── address.ts
            ├── env.ts
            ├── fonts.ts
            ├── raffle-abi.ts
            └── utils.ts

Tech Stack

• Solidity 0.8.19
• Foundry for testing and deployment
• Chainlink VRF v2.5 and Automation
• Next.js 14
• TypeScript
• Tailwind CSS
• Ethers.js for wallet and contract interactions
• shadcn/ui components