ProfitabilitySimulator.cs

using System.Numerics;
using Nethereum.Web3;
using Nethereum.Util;

public class ProfitabilitySimulator(
    Web3 web3,
    string dexRouterAddress,
    decimal flashloanPremiumPercent = 0.09m,
    decimal liquidationBonusPercent = 5.0m,
    decimal slippagePercent = 1.0m,
    decimal gasPriceGwei = 1,
    long estimatedGasUnits = 500_000)
{
    private static readonly string _routerV2Abi = @"[
        {
            'name':'getAmountsOut',
            'type':'function',
            'stateMutability':'view',
            'inputs':[
                {'name':'amountIn','type':'uint256'},
                {'name':'path','type':'address[]'}
            ],
            'outputs':[
                {'name':'amounts','type':'uint256[]'}
            ]
        }
    ]";

    public async Task<decimal> SimulateProfitAsync(
        decimal debtAmount, // (e.g., 5000 USDC)
        int debtAssetDecimals,
        string collateralAsset,
        string debtAsset
    )
    {
        var contract = web3.Eth.GetContract(_routerV2Abi, dexRouterAddress);
        var getAmountsOutFunc = contract.GetFunction("getAmountsOut");

        var debtAmountWei = UnitConversion.Convert.ToWei(debtAmount, debtAssetDecimals);

        var path = new[] { collateralAsset, debtAsset };

        // Estimate how much debtAsset we get when swapping collateral
        var expectedAmounts = await getAmountsOutFunc.CallAsync<List<BigInteger>>(debtAmountWei, path);

        if (expectedAmounts.Count != 2)
            throw new Exception("Invalid amountsOut length");

        var expectedSwapOutput = Web3.Convert.FromWei(expectedAmounts[1], debtAssetDecimals);

        var collateralReceived = debtAmount * (1 + liquidationBonusPercent / 100m);

        var collateralAfterSlippage = collateralReceived * (1 - slippagePercent / 100m);

        var flashloanCost = debtAmount * (flashloanPremiumPercent / 100m);

        // Gas cost (in ETH)
        var gasPriceWei = UnitConversion.Convert.ToWei(gasPriceGwei, UnitConversion.EthUnit.Gwei);
        var gasCostEth = (decimal)(estimatedGasUnits * gasPriceWei) / (decimal)Math.Pow(10, 18);

        // Gross profit
        var grossProfit = collateralAfterSlippage - (debtAmount + flashloanCost);

        // Subtract gas cost in USD terms (approximate)
        // You could use ETH/USD price from Chainlink to be more accurate
        var gasCostUsd = gasCostEth * 3100; // assume ETH price is 3100 USD
        var netProfit = grossProfit - gasCostUsd;

        return netProfit;
    }

    public async Task<bool> IsProfitableAsync(
        decimal debtAmount,
        int debtAssetDecimals,
        string collateralAsset,
        string debtAsset
    )
    {
        var profit = await SimulateProfitAsync(debtAmount, debtAssetDecimals, collateralAsset, debtAsset);
        return profit > 0;
    }
}