Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.19;

/**
 * @title STATE Activation & Buyback Contract
 * @author NWO.CAPITAL
 * @notice Users pay ETH to activate their payout window.
 *         30% goes to deployer operations wallet.
 *         70% auto-buys STATE from DEX to create buy pressure.
 * @dev Deployed on Ethereum mainnet
 */

import "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/security/ReentrancyGuard.sol";

contract STATEActivationBuyback is Ownable, ReentrancyGuard {
    
    // ============ IMMUTABLE PARAMETERS ============
    
    /// @notice Deployer/operations wallet - receives 30% of ETH
    address public immutable DEPLOYER_WALLET;
    
    /// @notice STATE token contract address
    address public immutable STATE_TOKEN;
    
    /// @notice WETH address for Uniswap routing
    address public immutable WETH;
    
    /// @notice Uniswap V2 Router for buybacks
    IUniswapV2Router02 public immutable UNISWAP_ROUTER;
    
    /// @notice Activation fee in ETH (~$9 USD)
    uint256 public constant ACTIVATION_FEE = 0.003 ether;
    
    /// @notice Deployer share: 30%
    uint256 public constant DEPLOYER_SHARE = 30;
    
    /// @notice Buyback share: 70%
    uint256 public constant BUYBACK_SHARE = 70;
    
    /// @notice Total basis points
    uint256 public constant TOTAL_BPS = 100;
    
    /// @notice Slippage tolerance for buybacks (2%)
    uint256 public constant SLIPPAGE_TOLERANCE = 200;
    
    // ============ STATE VARIABLES ============
    
    /// @notice Tracks total ETH collected from activations
    uint256 public totalEthCollected;
    
    /// @notice Tracks total ETH sent to deployer
    uint256 public totalEthToDeployer;
    
    /// @notice Tracks total ETH used for buybacks
    uint256 public totalEthForBuyback;
    
    /// @notice Tracks total STATE tokens bought back
    uint256 public totalStateBoughtBack;
    
    /// @notice Tracks user activation status
    mapping(address => bool) public hasActivated;
    
    /// @notice Backend signer for authorizing claims
    address public backendSigner;
    
    /// @notice Used nonces (prevents replay attacks)
    mapping(bytes32 => bool) public usedNonces;
    
    // ============ EVENTS ============
    
    event ActivationPaid(
        address indexed user,
        uint256 ethAmount,
        uint256 deployerShare,
        uint256 buybackShare,
        uint256 stateBought
    );
    
    event TokensClaimed(
        address indexed user,
        uint256 amount,
        bytes32 indexed nonce
    );
    
    event BackendSignerUpdated(address indexed oldSigner, address indexed newSigner);
    
    // ============ ERRORS ============
    
    error InvalidETHAmount();
    error ActivationFailed();
    error BuybackFailed();
    error TransferFailed();
    error InvalidTokenAddress();
    error InvalidRouterAddress();
    error InvalidSignature();
    error NonceAlreadyUsed();
    error ActivationRequired();
    error AlreadyActivated();
    error InsufficientContractBalance();
    
    // ============ CONSTRUCTOR ============
    
    constructor(
        address _stateToken,
        address _weth,
        address _uniswapRouter,
        address _deployerWallet,
        address _backendSigner
    ) Ownable(msg.sender) {
        if (_stateToken == address(0)) revert InvalidTokenAddress();
        if (_uniswapRouter == address(0)) revert InvalidRouterAddress();
        if (_deployerWallet == address(0)) revert InvalidTokenAddress();
        if (_backendSigner == address(0)) revert InvalidTokenAddress();
        
        STATE_TOKEN = _stateToken;
        WETH = _weth;
        UNISWAP_ROUTER = IUniswapV2Router02(_uniswapRouter);
        DEPLOYER_WALLET = _deployerWallet;
        backendSigner = _backendSigner;
    }
    // ============ ACTIVATION WITH AUTO-BUYBACK ============
    
    /**
     * @notice User pays ETH to activate their payout window
     * @dev Sends 30% to deployer, 70% buys STATE from DEX
     */
    function activate() external payable nonReentrant {
        if (hasActivated[msg.sender]) revert AlreadyActivated();
        if (msg.value != ACTIVATION_FEE) revert InvalidETHAmount();
        
        // Calculate shares
        uint256 deployerAmount = (msg.value * DEPLOYER_SHARE) / TOTAL_BPS;
        uint256 buybackAmount = msg.value - deployerAmount;
        
        // Update tracking
        totalEthCollected += msg.value;
        
        // 1. Send 30% to deployer wallet
        (bool deployerSuccess, ) = payable(DEPLOYER_WALLET).call{value: deployerAmount}("");
        if (!deployerSuccess) revert TransferFailed();
        totalEthToDeployer += deployerAmount;
        
        // 2. Use 70% to buy STATE from DEX
        uint256 stateBought = _executeBuyback(buybackAmount);
        
        // 3. Record user activation
        hasActivated[msg.sender] = true;
        
        emit ActivationPaid(
            msg.sender,
            msg.value,
            deployerAmount,
            buybackAmount,
            stateBought
        );
    }
    
    // ============ CLAIM EARNED TOKENS ============
    
    function claim(
        uint256 amount,
        bytes32 nonce,
        bytes memory signature,
        uint256 deadline
    ) external nonReentrant {
        // Verify user activated
        if (!hasActivated[msg.sender]) revert ActivationRequired();
        
        // Check deadline not expired
        if (block.timestamp > deadline) revert TransferFailed();
        
        // Check nonce not used before
        if (usedNonces[nonce]) revert NonceAlreadyUsed();
        
        // Verify backend signature
        bytes32 message = keccak256(abi.encodePacked(
            msg.sender,
            amount,
            nonce,
            deadline,
            address(this)
        ));
        bytes32 ethSignedMessage = keccak256(abi.encodePacked(
            "\x19Ethereum Signed Message:\n32",
            message
        ));
        
        address signer = recoverSigner(ethSignedMessage, signature);
        if (signer != backendSigner) revert InvalidSignature();
        
        // Mark nonce used
        usedNonces[nonce] = true;
        
        // Verify contract has enough STATE
        if (IERC20(STATE_TOKEN).balanceOf(address(this)) < amount) {
            revert InsufficientContractBalance();
        }
        
        // Send STATE to user
        IERC20(STATE_TOKEN).transfer(msg.sender, amount);
        
        emit TokensClaimed(msg.sender, amount, nonce);
    }
    
    // ============ INTERNAL FUNCTIONS ============
    
    function _executeBuyback(uint256 _ethAmount) internal returns (uint256) {
        address[] memory path = new address[](2);
        path[0] = WETH;
        path[1] = STATE_TOKEN;
        
        // Get expected output
        uint256[] memory amounts = UNISWAP_ROUTER.getAmountsOut(_ethAmount, path);
        uint256 expectedOutput = amounts[1];
        
        // Apply 2% slippage (98% of expected)
        uint256 minOutput = (expectedOutput * (10000 - SLIPPAGE_TOLERANCE)) / 10000;
        
        uint256 deadline = block.timestamp + 5 minutes;
        
        uint256[] memory swapResults = UNISWAP_ROUTER.swapExactETHForTokens{value: _ethAmount}(
            minOutput,
            path,
            address(this),
            deadline
        );
        
        uint256 stateReceived = swapResults[1];
        
        totalEthForBuyback += _ethAmount;
        totalStateBoughtBack += stateReceived;
        
        return stateReceived;
    }
    
    function recoverSigner(bytes32 ethSignedMessage, bytes memory signature) 
        internal 
        pure 
        returns (address) 
    {
        require(signature.length == 65, "Invalid signature length");
        
        bytes32 r;
        bytes32 s;
        uint8 v;
        
        assembly {
            r := mload(add(signature, 32))
            s := mload(add(signature, 64))
            v := byte(0, mload(add(signature, 96)))
        }
        
        if (v < 27) v += 27;
        
        return ecrecover(ethSignedMessage, v, r, s);
    }
    
    // ============ ADMIN FUNCTIONS ============
    
    function setBackendSigner(address _newSigner) external onlyOwner {
        require(_newSigner != address(0), "Invalid address");
        address oldSigner = backendSigner;
        backendSigner = _newSigner;
        emit BackendSignerUpdated(oldSigner, _newSigner);
    }
    
    function fundContract(uint256 amount) external {
        IERC20(STATE_TOKEN).transferFrom(msg.sender, address(this), amount);
    }
    
    function emergencyWithdrawState(address _to, uint256 _amount) external onlyOwner {
        IERC20(STATE_TOKEN).transfer(_to, _amount);
    }
    
    function emergencyWithdrawETH(address _to, uint256 _amount) external onlyOwner {
        (bool success, ) = payable(_to).call{value: _amount}("");
        if (!success) revert TransferFailed();
    }
    
    // ============ VIEW FUNCTIONS ============
    
    function isActivated(address user) external view returns (bool) {
        return hasActivated[user];
    }
    
    function getContractBalance() external view returns (uint256) {
        return IERC20(STATE_TOKEN).balanceOf(address(this));
    }
    
    function isNonceUsed(bytes32 nonce) external view returns (bool) {
        return usedNonces[nonce];
    }
    
    receive() external payable {
        revert("Use activate() function");
    }
}

// SPDX-License-Identifier: MIT
// 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;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;

import {Context} from "../utils/Context.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);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/IERC20.sol)

pragma solidity >=0.4.16;

/**
 * @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);
}

pragma solidity >=0.6.2;

import './IUniswapV2Router01.sol';

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    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 swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

pragma solidity >=0.6.2;

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

pragma solidity ^0.8.20;

/**
 * @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;
    }
}