Cryo Explorer Ethereum Mainnet

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

// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol


// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)


/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * The initial owner is set to the address provided by the deployer. This can
 * later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    /**
     * @dev The caller account is not authorized to perform an operation.
     */
    error OwnableUnauthorizedAccount(address account);

    /**
     * @dev The owner is not a valid owner account. (eg. `address(0)`)
     */
    error OwnableInvalidOwner(address owner);

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
     */
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/security/ReentrancyGuard.sol


// OpenZeppelin Contracts (last updated v4.9.0) (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @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 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;

    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
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // 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;
    }
}

// File: @openzeppelin/contracts/security/Pausable.sol


// OpenZeppelin Contracts (last updated v4.7.0) (security/Pausable.sol)

pragma solidity ^0.8.0;


/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor() {
        _paused = false;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        require(!paused(), "Pausable: paused");
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        require(paused(), "Pausable: not paused");
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol


// OpenZeppelin Contracts (last updated v5.1.0) (token/ERC20/IERC20.sol)


/**
 * @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);
}

// File: contracts/TrustSwap.sol

interface IUniswapV2Router {
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    
    function WETH() external pure returns (address);
    
    function getAmountsOut(
        uint amountIn, 
        address[] calldata path
    ) external view returns (uint[] memory amounts);
}

contract TRUSTSWAP is Ownable, ReentrancyGuard, Pausable {
    IUniswapV2Router public router;
    address public virtualToken;
    address public feeCollector;
    address public immutable WETH;
    
    // Fee settings
    uint256 public platformFeeBasisPoints = 25; // 0.25% fee (25/10000)
    uint256 public constant BASIS_POINTS_DENOMINATOR = 10000;
    uint256 public constant MIN_FEE_BASIS_POINTS = 0;
    uint256 public constant MAX_FEE_BASIS_POINTS = 100;
    
    // Events
    event TokensSwapped(
        address indexed user,
        address indexed tokenIn,
        address indexed tokenOut,
        uint256 amountIn,
        uint256 amountOut,
        uint256 feeAmount
    );
    
    event ETHSwapped(
        address indexed user,
        address indexed tokenOut,
        uint256 ethAmount,
        uint256 tokenAmount,
        uint256 feeAmount
    );
    
    event FeeCollectorUpdated(address indexed oldCollector, address indexed newCollector);
    event RouterUpdated(address indexed oldRouter, address indexed newRouter);
    event FeeUpdated(uint256 oldFee, uint256 newFee);
    
    constructor(
        address _router,
        address _virtualToken,
        address _feeCollector
    ) Ownable(msg.sender) {
        require(_router != address(0), "Router cannot be zero address");
        require(_virtualToken != address(0), "Virtual token cannot be zero address");
        require(_feeCollector != address(0), "Fee collector cannot be zero address");
        
        router = IUniswapV2Router(_router);
        virtualToken = _virtualToken;
        feeCollector = _feeCollector;
        WETH = router.WETH();
    }
    
    // Admin functions
    function setRouter(address _router) external onlyOwner {
        require(_router != address(0), "Router cannot be zero address");
        address oldRouter = address(router);
        router = IUniswapV2Router(_router);
        emit RouterUpdated(oldRouter, _router);
    }
    
    function setFeeCollector(address _feeCollector) external onlyOwner {
        require(_feeCollector != address(0), "Fee collector cannot be zero address");
        address oldCollector = feeCollector;
        feeCollector = _feeCollector;
        emit FeeCollectorUpdated(oldCollector, _feeCollector);
    }
    
    function setFeePercentage(uint256 _newFeeBasisPoints) external onlyOwner {
        require(_newFeeBasisPoints >= MIN_FEE_BASIS_POINTS, "Fee too low");
        require(_newFeeBasisPoints <= MAX_FEE_BASIS_POINTS, "Fee too high");
        
        uint256 oldFee = platformFeeBasisPoints;
        platformFeeBasisPoints = _newFeeBasisPoints;
        emit FeeUpdated(oldFee, _newFeeBasisPoints);
    }
    
    function togglePause() external onlyOwner {
        if (paused()) {
            _unpause();
        } else {
            _pause();
        }
    }
    
    // View functions
    function calculatePlatformFee(uint256 amount) public view returns (uint256) {
        return (amount * platformFeeBasisPoints) / BASIS_POINTS_DENOMINATOR;
    }
    
    function getAmountsOut(
        uint256 amountIn,
        address[] calldata path
    ) external view returns (uint256[] memory) {
        return router.getAmountsOut(amountIn, path);
    }
    
    // Get expected output amounts with fee deducted (for UI purposes)
    function getAmountsOutWithFee(
        uint256 amountIn,
        address[] calldata path
    ) external view returns (uint256[] memory amounts, uint256 feeAmount) {
        // Check if this is a swap to or from VIRTUAL
        bool isToVirtual = path[path.length - 1] == virtualToken;
        bool isFromVirtual = path[0] == virtualToken;
        
        uint256[] memory rawAmounts = router.getAmountsOut(amountIn, path);
        
        if (isFromVirtual) {
            // When buying with VIRTUAL, fee is taken from input
            feeAmount = calculatePlatformFee(amountIn);
            // Calculate output with reduced input
            uint256 amountInAfterFee = amountIn - feeAmount;
            if (amountInAfterFee > 0) {
                amounts = router.getAmountsOut(amountInAfterFee, path);
            } else {
                // If fee consumes all input, return zeros
                amounts = new uint256[](path.length);
            }
        } else if (isToVirtual) {
            // When selling for VIRTUAL, fee is taken from output
            amounts = rawAmounts;
            feeAmount = calculatePlatformFee(rawAmounts[rawAmounts.length - 1]);
            // Adjust final output after fee
            amounts[amounts.length - 1] = rawAmounts[rawAmounts.length - 1] - feeAmount;
        } else {
            // Non-VIRTUAL swaps - still charge fee in VIRTUAL (must be handled separately)
            amounts = rawAmounts;
            feeAmount = 0; // Fee must be supplied separately in VIRTUAL
        }
        
        return (amounts, feeAmount);
    }
    
    // Get ETH to token amounts with fee calculation (for UI purposes)
    function getETHToTokenAmountsWithFee(
        uint256 ethAmountIn,
        address tokenOut
    ) external view returns (uint256 expectedTokens, uint256 feeAmountETH) {
        address[] memory path = new address[](2);
        path[0] = WETH;
        path[1] = tokenOut;
        
        // Calculate fee in ETH
        feeAmountETH = calculatePlatformFee(ethAmountIn);
        uint256 ethAmountAfterFee = ethAmountIn - feeAmountETH;
        
        // Get expected tokens with reduced ETH input
        if (ethAmountAfterFee > 0) {
            uint256[] memory amountsAfterFee = router.getAmountsOut(ethAmountAfterFee, path);
            expectedTokens = amountsAfterFee[1];
        } else {
            expectedTokens = 0;
        }
        
        return (expectedTokens, feeAmountETH);
    }
    
    // Simplified function for buying with VIRTUAL (fee taken from input)
    function swapVirtualWithFee(
        uint256 amountIn,
        uint256 amountOutMin,
        address tokenOut,
        uint256 deadline
    ) external nonReentrant whenNotPaused returns (uint256[] memory) {
        require(tokenOut != address(0), "Invalid token out address");
        require(tokenOut != virtualToken, "Cannot swap VIRTUAL for itself");
        
        // Calculate fee
        uint256 feeAmount = calculatePlatformFee(amountIn);
        uint256 amountInAfterFee = amountIn - feeAmount;
        
        require(amountInAfterFee > 0, "Fee exceeds input amount");
        
        // Transfer total amount from user (includes fee)
        IERC20(virtualToken).transferFrom(msg.sender, address(this), amountIn);
        
        // Transfer fee to fee collector
        IERC20(virtualToken).transfer(feeCollector, feeAmount);
        
        // Prepare path
        address[] memory path = new address[](2);
        path[0] = virtualToken;
        path[1] = tokenOut;
        
        // Record balance before swap
        uint256 balanceBefore = IERC20(tokenOut).balanceOf(msg.sender);
        
        // Approve router to spend VIRTUAL
        IERC20(virtualToken).approve(address(router), amountInAfterFee);
        
        // Execute swap
        router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
            amountInAfterFee,
            amountOutMin,
            path,
            msg.sender,
            deadline
        );
        
        // Calculate output amount
        uint256 balanceAfter = IERC20(tokenOut).balanceOf(msg.sender);
        uint256 amountOut = balanceAfter - balanceBefore;
        
        // Prepare return amounts
        uint256[] memory amounts = new uint256[](2);
        amounts[0] = amountIn;
        amounts[1] = amountOut;
        
        emit TokensSwapped(
            msg.sender,
            virtualToken,
            tokenOut,
            amountIn,
            amountOut,
            feeAmount
        );
        
        return amounts;
    }
    
    // Simplified function for selling for VIRTUAL (fee taken from output)
    function swapForVirtualWithFee(
        address tokenIn,
        uint256 amountIn,
        uint256 amountOutMin,
        uint256 deadline
    ) external nonReentrant whenNotPaused returns (uint256[] memory) {
        require(tokenIn != address(0), "Invalid token in address");
        require(tokenIn != virtualToken, "Cannot swap VIRTUAL for itself");
        
        // Transfer input tokens from user
        IERC20(tokenIn).transferFrom(msg.sender, address(this), amountIn);
        
        // Prepare path
        address[] memory path = new address[](2);
        path[0] = tokenIn;
        path[1] = virtualToken;
        
        // Approve router to spend input tokens
        IERC20(tokenIn).approve(address(router), amountIn);
        
        // Record VIRTUAL balance before swap
        uint256 balanceBefore = IERC20(virtualToken).balanceOf(address(this));
        
        // Execute swap to contract first
        router.swapExactTokensForTokensSupportingFeeOnTransferTokens(
            amountIn,
            0, // We'll check minimum output manually
            path,
            address(this),
            deadline
        );
        
        // Calculate received amount
        uint256 balanceAfter = IERC20(virtualToken).balanceOf(address(this));
        uint256 totalReceived = balanceAfter - balanceBefore;
        
        // Calculate fee
        uint256 feeAmount = calculatePlatformFee(totalReceived);
        uint256 amountToSend = totalReceived - feeAmount;
        
        // Check minimum output requirement
        require(amountToSend >= amountOutMin, "Insufficient output amount");
        
        // Transfer fee to fee collector
        IERC20(virtualToken).transfer(feeCollector, feeAmount);
        
        // Transfer remaining amount to user
        IERC20(virtualToken).transfer(msg.sender, amountToSend);
        
        // Prepare return amounts
        uint256[] memory amounts = new uint256[](2);
        amounts[0] = amountIn;
        amounts[1] = amountToSend;
        
        emit TokensSwapped(
            msg.sender,
            tokenIn,
            virtualToken,
            amountIn,
            amountToSend,
            feeAmount
        );
        
        return amounts;
    }
    
    // New function: Swap ETH for tokens with fee
    function swapETHForTokensWithFee(
        address tokenOut,
        uint256 amountOutMin,
        uint256 deadline
    ) external payable nonReentrant whenNotPaused returns (uint256) {
        require(tokenOut != address(0), "Invalid token out address");
        require(tokenOut != WETH, "Use DEX directly for ETH to WETH");
        require(msg.value > 0, "Must send ETH");
        
        // Calculate fee in ETH
        uint256 feeAmount = calculatePlatformFee(msg.value);
        uint256 swapAmount = msg.value - feeAmount;
        
        require(swapAmount > 0, "Fee exceeds ETH amount");
        
        // Transfer ETH fee to fee collector
        (bool feeSent, ) = payable(feeCollector).call{value: feeAmount}("");
        require(feeSent, "Fee transfer failed");
        
        // Prepare path
        address[] memory path = new address[](2);
        path[0] = WETH;
        path[1] = tokenOut;
        
        // Record balance before swap
        uint256 balanceBefore = IERC20(tokenOut).balanceOf(msg.sender);
        
        // Execute swap with remaining ETH
        router.swapExactETHForTokensSupportingFeeOnTransferTokens{value: swapAmount}(
            amountOutMin,
            path,
            msg.sender,
            deadline
        );
        
        // Calculate output amount
        uint256 balanceAfter = IERC20(tokenOut).balanceOf(msg.sender);
        uint256 amountOut = balanceAfter - balanceBefore;
        
        emit ETHSwapped(
            msg.sender,
            tokenOut,
            msg.value,
            amountOut,
            feeAmount
        );
        
        return amountOut;
    }
    
    // Emergency function to recover any tokens accidentally sent to the contract
    function recoverERC20(address tokenAddress, uint256 tokenAmount) external onlyOwner {
        IERC20(tokenAddress).transfer(owner(), tokenAmount);
    }
    
    // Emergency function to recover ETH accidentally sent to the contract
    function recoverETH(uint256 amount) external onlyOwner {
        payable(owner()).transfer(amount);
    }
    
    // Required to receive ETH from swaps
    receive() external payable {}
}