Toucan Protocol Yield: Complete Guide to Carbon Credit DeFi Integration

// Example: Bridging carbon credits to blockchain
contract CarbonCreditBridge {
    struct CarbonCredit {
        uint256 id;
        string registry;
        uint256 vintage;
        string methodology;
        address owner;
    }
    
    mapping(uint256 => CarbonCredit) public carbonCredits;
    
    function bridgeCredit(
        uint256 creditId,
        string memory registry,
        uint256 vintage,
        string memory methodology
    ) external {
        // Verify credit authenticity with registry
        require(verifyWithRegistry(creditId, registry), "Invalid credit");
        
        // Mint corresponding TCO2 token
        TCO2Token(tco2Address).mint(msg.sender, 1 ether);
        
        // Store credit metadata
        carbonCredits[creditId] = CarbonCredit(
            creditId,
            registry,
            vintage,
            methodology,
            msg.sender
        );
    }
}

// NCT Pool Configuration
const NCTPoolParams = {
  minimumVintage: 2008,
  regions: ["Global"],
  standards: ["VCS", "Gold Standard", "CAR"],
  methodologies: ["All approved methodologies"]
};

// BCT Pool Configuration  
const BCTPoolParams = {
  minimumVintage: 2008,
  regions: ["Global"], 
  standards: ["VCS"],
  methodologies: ["Specific approved list"]
};

// Connect to Toucan Protocol contracts
const Web3 = require('web3');
const web3 = new Web3('YOUR_RPC_URL');

// Contract addresses on Polygon
const NCT_ADDRESS = '0xD838290e877E0188a4A44700463419ED96c16107';
const BCT_ADDRESS = '0x2F800Db0fdb5223b3C3f354886d907A671414A7F';
const UNISWAP_V3_ROUTER = '0xE592427A0AEce92De3Edee1F18E0157C05861564';

async function addLiquidityToNCTPool() {
    // Approve tokens for Uniswap interaction
    const nctContract = new web3.eth.Contract(ERC20_ABI, NCT_ADDRESS);
    const usdcContract = new web3.eth.Contract(ERC20_ABI, USDC_ADDRESS);
    
    // Approve NCT tokens
    await nctContract.methods.approve(
        UNISWAP_V3_ROUTER, 
        web3.utils.toWei('100', 'ether')
    ).send({from: userAddress});
    
    // Approve USDC tokens  
    await usdcContract.methods.approve(
        UNISWAP_V3_ROUTER,
        '100000000' // 100 USDC (6 decimals)
    ).send({from: userAddress});
    
    // Add liquidity to NCT/USDC pool
    const routerContract = new web3.eth.Contract(UNISWAP_V3_ABI, UNISWAP_V3_ROUTER);
    
    const params = {
        token0: NCT_ADDRESS,
        token1: USDC_ADDRESS,
        fee: 3000, // 0.3% fee tier
        tickLower: -276320,
        tickUpper: -276200,
        amount0Desired: web3.utils.toWei('100', 'ether'),
        amount1Desired: '100000000',
        amount0Min: 0,
        amount1Min: 0,
        recipient: userAddress,
        deadline: Math.floor(Date.now() / 1000) + 3600
    };
    
    return await routerContract.methods.mint(params).send({
        from: userAddress,
        gas: 500000
    });
}

// Yield farming contract for carbon tokens
contract CarbonYieldFarm {
    IERC20 public nctToken;
    IERC20 public rewardToken;
    
    mapping(address => uint256) public stakedBalances;
    mapping(address => uint256) public rewardDebt;
    
    uint256 public rewardPerBlock = 1e18; // 1 token per block
    uint256 public lastRewardBlock;
    uint256 public accRewardPerShare;
    
    function stake(uint256 amount) external {
        updateRewards();
        
        // Transfer NCT tokens to contract
        nctToken.transferFrom(msg.sender, address(this), amount);
        
        // Calculate pending rewards
        if (stakedBalances[msg.sender] > 0) {
            uint256 pending = (stakedBalances[msg.sender] * accRewardPerShare / 1e12) - rewardDebt[msg.sender];
            rewardToken.transfer(msg.sender, pending);
        }
        
        // Update user balance
        stakedBalances[msg.sender] += amount;
        rewardDebt[msg.sender] = stakedBalances[msg.sender] * accRewardPerShare / 1e12;
    }
    
    function updateRewards() internal {
        if (block.number <= lastRewardBlock) return;
        
        uint256 totalStaked = nctToken.balanceOf(address(this));
        if (totalStaked == 0) {
            lastRewardBlock = block.number;
            return;
        }
        
        uint256 blocksPassed = block.number - lastRewardBlock;
        uint256 rewards = blocksPassed * rewardPerBlock;
        accRewardPerShare += (rewards * 1e12) / totalStaked;
        lastRewardBlock = block.number;
    }
}

// Monitor NCT prices across DEXs
class CarbonArbitrageBot {
    constructor() {
        this.uniswapPrice = 0;
        this.sushiswapPrice = 0;
        this.quickswapPrice = 0;
        this.minProfitThreshold = 0.02; // 2% minimum profit
    }
    
    async fetchPrices() {
        // Get Uniswap V3 price
        this.uniswapPrice = await this.getUniswapPrice(NCT_ADDRESS, USDC_ADDRESS);
        
        // Get SushiSwap price
        this.sushiswapPrice = await this.getSushiPrice(NCT_ADDRESS, USDC_ADDRESS);
        
        // Get QuickSwap price
        this.quickswapPrice = await this.getQuickswapPrice(NCT_ADDRESS, USDC_ADDRESS);
    }
    
    async executeArbitrage() {
        await this.fetchPrices();
        
        const prices = [
            {exchange: 'Uniswap', price: this.uniswapPrice},
            {exchange: 'SushiSwap', price: this.sushiswapPrice},
            {exchange: 'QuickSwap', price: this.quickswapPrice}
        ];
        
        const sortedPrices = prices.sort((a, b) => a.price - b.price);
        const buyExchange = sortedPrices[0];
        const sellExchange = sortedPrices[2];
        
        const profit = (sellExchange.price - buyExchange.price) / buyExchange.price;
        
        if (profit > this.minProfitThreshold) {
            console.log(`Arbitrage opportunity: Buy on ${buyExchange.exchange} at $${buyExchange.price}, sell on ${sellExchange.exchange} at $${sellExchange.price}`);
            
            // Execute trades
            await this.buyNCT(buyExchange.exchange, 1000); // Buy 1000 NCT
            await this.sellNCT(sellExchange.exchange, 1000); // Sell 1000 NCT
        }
    }
}

// Portfolio management for carbon credits
class CarbonPortfolioManager {
    constructor() {
        this.targetAllocation = {
            NCT: 0.4,  // 40% NCT
            BCT: 0.3,  // 30% BCT  
            USDC: 0.3  // 30% stable
        };
        this.rebalanceThreshold = 0.05; // 5% deviation triggers rebalance
    }
    
    async getCurrentAllocation() {
        const nctBalance = await this.getTokenBalance(NCT_ADDRESS);
        const bctBalance = await this.getTokenBalance(BCT_ADDRESS);
        const usdcBalance = await this.getTokenBalance(USDC_ADDRESS);
        
        const totalValue = nctBalance.usdValue + bctBalance.usdValue + usdcBalance.usdValue;
        
        return {
            NCT: nctBalance.usdValue / totalValue,
            BCT: bctBalance.usdValue / totalValue,
            USDC: usdcBalance.usdValue / totalValue
        };
    }
    
    async rebalancePortfolio() {
        const currentAllocation = await this.getCurrentAllocation();
        
        // Check if rebalancing is needed
        for (const [token, currentPercent] of Object.entries(currentAllocation)) {
            const targetPercent = this.targetAllocation[token];
            const deviation = Math.abs(currentPercent - targetPercent);
            
            if (deviation > this.rebalanceThreshold) {
                console.log(`Rebalancing needed for ${token}: Current ${currentPercent}, Target ${targetPercent}`);
                await this.executeRebalance(currentAllocation);
                break;
            }
        }
    }
}

// Security features for carbon yield contracts
contract SecureCarbonYield {
    using SafeMath for uint256;
    
    // Reentrancy protection
    modifier nonReentrant() {
        require(!locked, "ReentrancyGuard: reentrant call");
        locked = true;
        _;
        locked = false;
    }
    
    // Emergency pause functionality
    modifier whenNotPaused() {
        require(!paused, "Contract is paused");
        _;
    }
    
    // Maximum stake per user (whale protection)
    uint256 public maxStakePerUser = 10000 ether;
    
    function emergencyWithdraw() external nonReentrant {
        uint256 amount = stakedBalances[msg.sender];
        require(amount > 0, "No stake to withdraw");
        
        stakedBalances[msg.sender] = 0;
        rewardDebt[msg.sender] = 0;
        
        nctToken.transfer(msg.sender, amount);
        emit EmergencyWithdraw(msg.sender, amount);
    }
}

// Calculate price impact before large trades
async function calculatePriceImpact(tokenAddress, amount) {
    const pair = await uniswapFactory.getPair(tokenAddress, USDC_ADDRESS);
    const reserves = await pair.getReserves();
    
    const tokenReserve = tokenAddress < USDC_ADDRESS ? reserves[0] : reserves[1];
    const usdcReserve = tokenAddress < USDC_ADDRESS ? reserves[1] : reserves[0];
    
    // Calculate price impact using constant product formula
    const priceImpact = amount / (tokenReserve + amount);
    
    console.log(`Price impact for ${amount} tokens: ${priceImpact * 100}%`);
    return priceImpact;
}

// Split large orders to minimize impact
async function executeLargeOrder(tokenAddress, totalAmount) {
    const maxSingleTradeImpact = 0.02; // 2% max impact per trade
    const chunks = [];
    let remainingAmount = totalAmount;
    
    while (remainingAmount > 0) {
        // Find optimal chunk size
        let chunkSize = remainingAmount * 0.1; // Start with 10% of remaining
        let impact = await calculatePriceImpact(tokenAddress, chunkSize);
        
        while (impact > maxSingleTradeImpact && chunkSize > remainingAmount * 0.01) {
            chunkSize *= 0.8; // Reduce chunk size
            impact = await calculatePriceImpact(tokenAddress, chunkSize);
        }
        
        chunks.push(chunkSize);
        remainingAmount -= chunkSize;
    }
    
    // Execute trades with delays
    for (const chunk of chunks) {
        await executeSwap(tokenAddress, chunk);
        await new Promise(resolve => setTimeout(resolve, 60000)); // 1 minute delay
    }
}

// Deposit NCT tokens to Aave for lending
async function depositToAave() {
    const aavePool = new web3.eth.Contract(AAVE_POOL_ABI, AAVE_POOL_ADDRESS);
    
    // Approve NCT tokens for Aave
    await nctContract.methods.approve(
        AAVE_POOL_ADDRESS,
        web3.utils.toWei('1000', 'ether')
    ).send({from: userAddress});
    
    // Deposit NCT tokens
    await aavePool.methods.supply(
        NCT_ADDRESS,
        web3.utils.toWei('1000', 'ether'),
        userAddress,
        0 // referral code
    ).send({from: userAddress});
    
    console.log('NCT tokens deposited to Aave successfully');
}

// Borrow against carbon collateral
async function borrowAgainstCarbon() {
    const aavePool = new web3.eth.Contract(AAVE_POOL_ABI, AAVE_POOL_ADDRESS);
    
    // Borrow USDC against NCT collateral
    await aavePool.methods.borrow(
        USDC_ADDRESS,
        '50000000', // 50 USDC
        2, // Variable rate mode
        0, // referral code
        userAddress
    ).send({from: userAddress});
    
    console.log('USDC borrowed against carbon collateral');
}

// Supply carbon tokens to Compound
async function supplyToCompound() {
    // Note: This assumes NCT has been listed on Compound
    const cNCTContract = new web3.eth.Contract(CERC20_ABI, CNCT_ADDRESS);
    
    // Approve NCT for cNCT contract
    await nctContract.methods.approve(
        CNCT_ADDRESS,
        web3.utils.toWei('500', 'ether')
    ).send({from: userAddress});
    
    // Mint cNCT tokens
    await cNCTContract.methods.mint(
        web3.utils.toWei('500', 'ether')
    ).send({from: userAddress});
    
    console.log('NCT tokens supplied to Compound');
}

// Carbon portfolio analytics
class CarbonPortfolioAnalytics {
    constructor() {
        this.positions = [];
        this.historicalData = [];
    }
    
    async trackYieldPerformance() {
        const currentPositions = await this.getCurrentPositions();
        
        const performance = {
            totalValue: 0,
            totalYield: 0,
            apy: 0,
            carbonCreditsOwned: 0
        };
        
        for (const position of currentPositions) {
            const currentValue = await this.getPositionValue(position);
            const initialValue = position.initialValue;
            const timeHeld = (Date.now() - position.startTime) / (1000 * 60 * 60 * 24); // days
            
            const positionYield = currentValue - initialValue;
            const positionAPY = (positionYield / initialValue) * (365 / timeHeld) * 100;
            
            performance.totalValue += currentValue;
            performance.totalYield += positionYield;
            performance.carbonCreditsOwned += position.carbonAmount;
        }
        
        performance.apy = performance.totalYield / (performance.totalValue - performance.totalYield) * 365 / this.getAverageHoldingPeriod() * 100;
        
        return performance;
    }
    
    generateReport() {
        const report = `
# Carbon Credit DeFi Portfolio Report

## Current Holdings
- Total Portfolio Value: $${this.totalValue.toFixed(2)}
- Total Carbon Credits: ${this.carbonCreditsOwned.toFixed(2)} tonnes CO2
- Average APY: ${this.apy.toFixed(2)}%

## Environmental Impact
- Carbon Offset: ${this.carbonCreditsOwned.toFixed(2)} tonnes CO2e
- Equivalent to: ${(this.carbonCreditsOwned * 0.4).toFixed(1)} cars off road for 1 year

## Top Performing Strategies
${this.getTopStrategies()}
        `;
        
        return report;
    }
}