ChronoStake

A Solidity-based NFT staking system that rewards NFT holders with ERC20 tokens over time. This project demonstrates how to implement a time-based staking mechanism where NFT holders earn yield tokens proportional to their holding period.

Overview

This project consists of three main smart contracts:

1. NFT.sol: An ERC721 token with staking capabilities
2. NftBase.sol: Base contract that implements the staking logic
3. YieldToken.sol: An ERC20 token that is minted as rewards for stakers

The system allows users to:

• Mint NFTs
• Earn yield tokens automatically by holding NFTs
• Collect accrued yield tokens at any time
• Transfer NFTs (which automatically collects rewards)

Features

• Time-based Rewards: NFT holders earn yield tokens based on how long they've held their NFTs
• Adjustable Reward Rates: Admin can change the reward rate at any time
• Staking Periods: Supports multiple staking periods with different reward rates
• Pause/Resume Staking: Admin can pause and resume the staking mechanism
• Automatic Reward Collection: Rewards are automatically collected when NFTs are transferred
• Batch Operations: Collect rewards for all owned NFTs in a single transaction

Smart Contracts

NFT.sol

The main NFT contract that users interact with. It extends NftBase and implements:

• Minting functionality (with a price of 0.01 ETH per NFT)
• Maximum supply of 10,000 NFTs
• Public sale toggle
• Admin functions for managing the contract

NftBase.sol

The core staking logic that:

• Tracks staking periods and reward rates
• Calculates rewards based on holding time
• Manages the collection of rewards
• Handles NFT transfers with automatic reward collection

YieldToken.sol

A standard ERC20 token with:

• Role-based access control
• Minting functionality restricted to authorized minters (the NFT contract)

Technical Details

Staking Mechanism

The staking system works by:

1. Recording the timestamp when an NFT is minted or transferred
2. Tracking different staking periods with their respective reward rates
3. Calculating rewards based on the formula: timeElapsed * dailyReward
4. Where dailyReward = (rewardRate * 10^18) / (24 * 60 * 60)

Reward Collection

Rewards can be collected in three ways:

1. Manually for a single NFT using collectYieldTokenForOne(tokenId)
2. In batch for all owned NFTs using collectYieldTokenForAll(address)
3. Automatically when transferring an NFT (rewards are sent to the previous owner)

Getting Started

Prerequisites

• Node.js v16+ (Note: v23.7.0 is used but not officially supported by Hardhat)
• npm or yarn
• Hardhat

Installation

1. Clone the repository:

git clone https://github.com/zxselimcan/chronostake.git
cd chronostake

2. Install dependencies:

npm install

Compilation

npx hardhat compile

Testing

Run the comprehensive test suite:

npx hardhat test

For test coverage:

npx hardhat coverage

Deployment

1. Set up your environment variables in a .env file:

PRIVATE_KEY=your_private_key
INFURA_API_KEY=your_infura_api_key
ETHERSCAN_API_KEY=your_etherscan_api_key

2. Deploy to a network:

npx hardhat run scripts/deploy.js --network <network_name>

Usage Examples

Minting NFTs

// Connect to the NFT contract
const nftContract = await ethers.getContractAt("NFT", nftContractAddress);

// Mint 2 NFTs for 0.02 ETH
await nftContract.mint(receiverAddress, 2, {
  value: ethers.parseEther("0.02"),
});

Checking Rewards

// Check rewards for a specific NFT
const rewards = await nftContract.collectableYieldTokenForOne(tokenId);
console.log(`Claimable rewards: ${ethers.formatEther(rewards)} YIELD`);

// Check rewards for all NFTs owned by an address
const totalRewards =
  await nftContract.collectableYieldTokenForAll(ownerAddress);
console.log(
  `Total claimable rewards: ${ethers.formatEther(totalRewards)} YIELD`
);

Collecting Rewards

// Collect rewards for a specific NFT
await nftContract.collectYieldTokenForOne(tokenId);

// Collect rewards for all owned NFTs
await nftContract.collectYieldTokenForAll(ownerAddress);

Admin Functions

// Toggle public sale status
await nftContract.togglePublicSaleStatus();

// Update reward rate (value between 1-1000)
await nftContract.setRewardRate(20);

// Pause staking
await nftContract.pauseStaking();

// Resume staking
await nftContract.continueStaking();

// Update base URI
await nftContract.setBaseURI("ipfs://newCID/");

// Withdraw contract funds
await nftContract.withdraw();