🏦 DeFi Staking Pool

A professional-grade Staking dApp built with Hardhat and Solidity. This project implements a "Synthetix-style" staking algorithm, allowing users to stake ERC20 tokens and earn rewards proportional to their share of the pool and the time staked.

🌟 Features

• Time-Based Rewards: Users earn rewards every second they are staked.
• Math Precision: Uses a "Global Odometer" (Reward Per Token) pattern for O(1) complexity, ensuring gas costs remain low regardless of user count.
• Security: Built with OpenZeppelin v5 (ReentrancyGuard, Ownable, SafeERC20).
• Admin Controls: Owner can set reward durations and fund the pool dynamically.
• Comprehensive Testing: Includes "Time Travel" tests to verify reward accumulation over time.

---

📂 Project Structure

• contracts/: Smart contracts (Staking.sol, MockERC20.sol).
• test/: Hardhat tests ensuring mathematical accuracy.
• ignition/modules/: Deployment modules for Hardhat Ignition.
• scripts/: Interaction scripts for mainnet/testnet and local time manipulation.

---

🛠️ Setup & Installation

1. Clone the repository

   git clone <your-repo-url>
   cd StakingPool

2. Install Dependencies

   npm install

3. Environment Configuration Create a .env file in the root directory (do not share this file!).

   # .env
   PRIVATE_KEY="your_wallet_private_key"
   SEPOLIA_RPC_URL="[https://sepolia.infura.io/v3/YOUR_KEY](https://sepolia.infura.io/v3/YOUR_KEY)"
   ETHERSCAN_API_KEY="your_etherscan_key"

---

🧪 Testing

We use Hardhat and Chai for testing. The test suite includes "Time Travel" scenarios to simulate days or weeks of staking in seconds.

npx hardhat test

What is tested?

• ✅ Staking & Withdrawing mechanics.
• ✅ Reward calculation accuracy (Math verification).
• ✅ Multi-user scenarios (ensuring no one steals rewards).
• ✅ Access controls (Owner functions).

---

🚀 Deployment

We use Hardhat Ignition for robust deployments.

Option 1: Local Blockchain (Fastest)

Great for development and frontend testing.

1. Start the Local Node:

npx hardhat node

2. Deploy:

npx hardhat ignition deploy ignition/modules/Deploy.js --network localhost

Option 2: Sepolia Testnet (Public)

Deploys to the real Ethereum test network.

npx hardhat ignition deploy ignition/modules/Deploy.js --network sepolia

---

🎮 Interaction Scripts

After deployment, you can interact with your contract using the provided scripts.

1. Setup & Stake (scripts/interact.js)

This script funds the pool, sets the reward rate, and stakes tokens on behalf of the owner.

• Note: If running on Sepolia, make sure to update the addresses in the script first.

npx hardhat run scripts/interact.js --network localhost
# OR
npx hardhat run scripts/interact.js --network sepolia

2. Time Travel Debugging (scripts/checkRewards.js)

Only works on localhost. This script simulates the passage of time (e.g., fast-forward 30 seconds) to verify rewards without waiting.

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

---

📜 Contract Details

StakingPool.sol

• Staking Token: The ERC20 token users deposit.
• Rewards Token: The ERC20 token users earn (can be the same or different).
• updateReward Modifier: The heartbeat of the contract. It updates the state whenever a user interacts, ensuring calculations are always precise down to the second.

---

🛡️ Security

• ReentrancyGuard: Prevents reentrancy attacks on withdraw/claim functions.
• SafeERC20: Handles non-standard ERC20 tokens securely.
• Rounding Errors: Minimized by scaling calculations by 1e18.