https://github.com/verumlotus/no-loss-erc721-raffle

No-loss NFT raffle that deposits user funds into a yield-bearing strategy and forwards all interest to the NFT creator..
https://github.com/verumlotus/no-loss-erc721-raffle

chainlink-vrf erc721 evm foundry nft solidity

Last synced: 15 days ago
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No-loss NFT raffle that deposits user funds into a yield-bearing strategy and forwards all interest to the NFT creator..

• Host: GitHub
• URL: https://github.com/verumlotus/no-loss-erc721-raffle
• Owner: verumlotus
• License: mit
• Created: 2022-05-26T17:10:21.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2022-05-26T20:33:49.000Z (over 2 years ago)
• Last Synced: 2024-12-21T12:34:58.297Z (28 days ago)
• Topics: chainlink-vrf, erc721, evm, foundry, nft, solidity
• Language: Solidity
• Homepage:
• Size: 28.3 KB
• Stars: 9
• Watchers: 3
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# No-Loss NFT Raffle

No-loss NFT raffle that deposits user funds into a yield-bearing strategy and forwards all interest to NFT creator.

## Background

Traditional auctions & raffles require users to deposit money that is not returned to them. [Premium Bond](https://en.wikipedia.org/wiki/Premium_Bond) inspired mechanisms (such as [PoolTogether](https://pooltogether.com/)) allow users to participate in a lottery with the ability to redeem their original deposit, regardless of whether they win. The `NFTRaffle.sol` contract in this repo contains similar logic for NFTs. An NFT creator is able to raffle off their NFT, collecting the interest generated from depositor's tokens during the raffle period. [Chainlink's VRF](https://docs.chain.link/docs/chainlink-vrf/) mechanism is leveraged to fairly determine a user at random (weighted by the size of their deposit). 



Traditional auctions & raffles require users to deposit money that is not returned to them. [Premium Bond](https://en.wikipedia.org/wiki/Premium_Bond) inspired mechanisms (such as [PoolTogether](https://pooltogether.com/)) allow users to participate in a lottery with the ability to redeem their original deposit, regardless of whether they win. The `NFTRaffle.sol` contract in this repo contains similar logic for NFTs. An NFT creator is able to raffle off their NFT, collecting the interest generated from depositor's tokens during the raffle period. [Chainlink's VRF](https://docs.chain.link/docs/chainlink-vrf/) mechanism is leveraged to fairly determine a user at random (weighted by the size of their deposit). 

## Flow for an NFT Raffler

- Acquires a Chainlink VRF Subscription Account and funds it with LINK token (see Chainlink docs [here](https://docs.chain.link/docs/chainlink-vrf/)

- Configures settings and deploys contract, adding the deployed contract address as a authorized Chainlink Consumer to the subscription account created above

- Escrows the NFT in the contract via `depositNFT`

- After the user deposit period is over, calls `investRaffleDeposits` to invest raffle deposits into a yield-bearing strategy (currently Yearn)

- After the interest generation period is over, calls `withdrawRaffleDepositsFromYearn` to withdraw the original yearn deposit along with interest. The interest generated is automatically transferred to the owner. 

## Flow for a user

- Calls `enterRaffle` with a specified amount of tokens to enter the raffle

- After the interest generation period is over, anyone can invoke `requestRandomWords`, which will trigger the chainlink VRF process to kick off

- The Chainlink VRF coordinator will invoke the `fulfillRandomWords` callback, which will randomly assign a winner

- All users can withdraw their original deposit via `withdrawRaffleDeposit`

- The winner can claim the NFT via `claimWinner`

## Build & Testing

This repo uses Foundry for both the build and testing flows. Run `forge build` to build the repo and `forge test` for tests.

## Improvements

This contract assumes that the interst-bearing strategy will return a positive interest, which is not always the case. A future iteration can be made more robust to account for a loss of funds and handle business logic accordingly. This contract is a prototype, and has not been gas-optimized either. 

## Acknowledgements

Part of this idea was inspired by [PoolTogether](https://pooltogether.com/) and they work they have done with their no-loss loterry. 

## Disclaimer

This was a minimal implementation created for personal uses and for fun, and should not be used in production.