Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";

interface IUniswapV2Router {
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
}

interface IPool {
    function flashLoan(
        address receiverAddress,
        address[] calldata assets,
        uint256[] calldata amounts,
        uint256[] calldata modes,
        address onBehalfOf,
        bytes calldata params,
        uint16 referralCode
    ) external;
}

contract FlashLoanArbitrage is ReentrancyGuard {
    address public owner;
    address public immutable POOL_ADDRESS;
    address public uniswapRouter;
    address public sushiswapRouter;
    address public constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    
    event DebugLog(string message, address asset, uint256 amount);
    event ArbitrageExecuted(address indexed asset, uint256 profit, address indexed initiator);

    constructor(address _poolAddress, address _uniswapRouter, address _sushiswapRouter) {
        owner = msg.sender;
        POOL_ADDRESS = _poolAddress;
        uniswapRouter = _uniswapRouter;
        sushiswapRouter = _sushiswapRouter;
    }
    
    function executeFlashLoan(
        address asset,
        uint256 amount
    ) external {
        require(msg.sender == owner, "Not authorized");
        
        // Declare arrays for flash loan parameters
        address[] memory assets = new address[](1);
        uint256[] memory amounts = new uint256[](1);
        uint256[] memory modes = new uint256[](1);
        
        assets[0] = asset;
        amounts[0] = amount;
        modes[0] = 0; // No debt mode, full repayment expected
        
        IPool(POOL_ADDRESS).flashLoan(
            address(this),
            assets,
            amounts,
            modes,
            address(this),
            abi.encode(asset, amount),
            0
        );
    }
    
    function executeOperation(
        address[] calldata assets,
        uint256[] calldata amounts,
        uint256[] calldata premiums,
        address initiator,
        bytes calldata params
    ) external returns (bool) {
        require(msg.sender == POOL_ADDRESS, "Caller must be lending pool");
        require(initiator == address(this), "Initiator must be this contract");
        
        // Extract the borrowed asset and amount
        address asset = assets[0];
        uint256 amount = amounts[0];
        uint256 premium = premiums[0];
        
        // Decode parameters
        (address borrowedAsset, uint256 borrowedAmount) = abi.decode(params, (address, uint256));
        require(asset == borrowedAsset, "Asset mismatch");
        require(amount == borrowedAmount, "Amount mismatch");
        
        emit DebugLog("Flash loan received", asset, amount);
        
        // Create path for Uniswap swap (asset → WETH)
        address[] memory uniswapPath = new address[](2);
        uniswapPath[0] = asset;
        uniswapPath[1] = WETH;
        
        // Approve Uniswap router to spend our tokens
        IERC20(asset).approve(uniswapRouter, amount);
        
        // Execute swap on Uniswap (asset → WETH)
        IUniswapV2Router(uniswapRouter).swapExactTokensForTokens(
            amount,
            0, // Accept any amount
            uniswapPath,
            address(this),
            block.timestamp + 300
        );
        
        // Create path for SushiSwap swap (WETH → asset)
        address[] memory sushiswapPath = new address[](2);
        sushiswapPath[0] = WETH;
        sushiswapPath[1] = asset;
        
        // Get WETH balance
        uint256 wethBalance = IERC20(WETH).balanceOf(address(this));
        
        // Approve SushiSwap router to spend our WETH
        IERC20(WETH).approve(sushiswapRouter, wethBalance);
        
        // Execute swap on SushiSwap (WETH → asset)
        IUniswapV2Router(sushiswapRouter).swapExactTokensForTokens(
            wethBalance,
            0, // Accept any amount
            sushiswapPath,
            address(this),
            block.timestamp + 300
        );
        
        // Calculate amount to repay (initial amount + premium)
        uint256 amountToRepay = amount + premium;
        
        // Check if arbitrage was profitable
        uint256 finalBalance = IERC20(asset).balanceOf(address(this));
        require(finalBalance >= amountToRepay, "Insufficient balance to repay flash loan");
        
        // Approve the lending pool to pull the owed amount
        IERC20(asset).approve(POOL_ADDRESS, amountToRepay);
        
        // Calculate profit
        uint256 profit = finalBalance - amountToRepay;
        emit ArbitrageExecuted(asset, profit, initiator);
        
        return true;
    }
    
    function withdraw(address token) external {
        require(msg.sender == owner, "Not authorized");
        uint256 balance = IERC20(token).balanceOf(address(this));
        IERC20(token).transfer(owner, balance);
    }
    
    // Function to receive ETH
    receive() external payable {}
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC-20 standard as defined in the ERC.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the value of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 value) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 value) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/ReentrancyGuard.sol)

pragma solidity ^0.8.20;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If EIP-1153 (transient storage) is available on the chain you're deploying at,
 * consider using {ReentrancyGuardTransient} instead.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant NOT_ENTERED = 1;
    uint256 private constant ENTERED = 2;

    uint256 private _status;

    /**
     * @dev Unauthorized reentrant call.
     */
    error ReentrancyGuardReentrantCall();

    constructor() {
        _status = NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be NOT_ENTERED
        if (_status == ENTERED) {
            revert ReentrancyGuardReentrantCall();
        }

        // Any calls to nonReentrant after this point will fail
        _status = ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = NOT_ENTERED;
    }

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == ENTERED;
    }
}