// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {Ownable} from '@openzeppelin/contracts/access/Ownable.sol';
import {Pausable} from '@openzeppelin/contracts/security/Pausable.sol';
import {ReentrancyGuard} from '@openzeppelin/contracts/security/ReentrancyGuard.sol';
import {IERC20, SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
import {IUniswapV2Router02} from './IUniswapV2Router02.sol';
import {FeeSharingSystem} from './FeeSharingSystem.sol';
/**
 * @title X2Y2Compounder
 * @notice It sells WETH to X2Y2 using Uniswap V2.
 * @dev Prime shares represent the number of shares in the FeeSharingSystem. When not specified, shares represent secondary shares in this contract.
 */
contract X2Y2Compounder is Ownable, Pausable, ReentrancyGuard {
    using SafeERC20 for IERC20;
    // Maximum buffer between 2 harvests (in blocks)
    uint256 public constant MAXIMUM_HARVEST_BUFFER_BLOCKS = 6500;
    // FeeSharingSystem (handles the distribution of WETH for X2Y2 stakers)
    FeeSharingSystem public immutable feeSharingSystem;
    // Uniswap V2
    IUniswapV2Router02 public immutable uniswapRouter;
    // Minimum deposit in X2Y2 (it is derived from the FeeSharingSystem)
    uint256 public immutable MINIMUM_DEPOSIT_X2Y2;
    // Token Address
    IERC20 public immutable x2y2Token;
    // Reward token (WETH)
    IERC20 public immutable rewardToken;
    // Whether harvest and WETH selling is triggered automatically at user action
    bool public canHarvest;
    // Buffer between two harvests (in blocks)
    uint256 public harvestBufferBlocks;
    // Last user action block
    uint256 public lastHarvestBlock;
    // Maximum price of X2Y2 (in WETH) multiplied 1e18 (e.g., 0.0004 ETH --> 4e14)
    uint256 public maxPriceX2Y2InWETH;
    // Threshold amount (in rewardToken)
    uint256 public thresholdAmount;
    // Total number of shares outstanding
    uint256 public totalShares;
    // Keeps track of number of user shares
    mapping(address => uint256) public userInfo;
    event ConversionToX2Y2(uint256 amountSold, uint256 amountReceived);
    event Deposit(address indexed user, uint256 amount);
    event FailedConversion();
    event HarvestStart();
    event HarvestStop();
    event NewHarvestBufferBlocks(uint256 harvestBufferBlocks);
    event NewMaximumPriceX2Y2InWETH(uint256 value);
    event NewThresholdAmount(uint256 thresholdAmount);
    event Withdraw(address indexed user, uint256 amount);
    /**
     * @notice Constructor
     * @param _feeSharingSystem address of the fee sharing system contract
     * @param _uniswapRouter address of the Uniswap v3 router
     */
    constructor(FeeSharingSystem _feeSharingSystem, IUniswapV2Router02 _uniswapRouter) {
        feeSharingSystem = FeeSharingSystem(_feeSharingSystem);
        x2y2Token = IERC20(_feeSharingSystem.x2y2Token());
        rewardToken = IERC20(_feeSharingSystem.rewardToken());
        uniswapRouter = _uniswapRouter;
        x2y2Token.approve(address(_feeSharingSystem), type(uint256).max);
        rewardToken.approve(address(_uniswapRouter), type(uint256).max);
        MINIMUM_DEPOSIT_X2Y2 = FeeSharingSystem(_feeSharingSystem).PRECISION_FACTOR();
    }
    /**
     * @notice Deposit X2Y2 tokens
     * @param amount amount to deposit (in X2Y2)
     * @dev There is a limit of 1 X2Y2 per deposit to prevent potential manipulation of the shares
     */
    function deposit(uint256 amount) external nonReentrant whenNotPaused {
        require(amount >= MINIMUM_DEPOSIT_X2Y2, 'Deposit: Amount must be >= 1 X2Y2');
        if (
            block.number > (lastHarvestBlock + harvestBufferBlocks) &&
            canHarvest &&
            totalShares != 0
        ) {
            _harvestAndSellAndCompound();
        }
        // Transfer X2Y2 tokens to this address
        x2y2Token.safeTransferFrom(msg.sender, address(this), amount);
        // Fetch the total number of X2Y2 staked by this contract
        uint256 totalAmountStaked = feeSharingSystem.calculateSharesValueInX2Y2(address(this));
        uint256 currentShares = totalShares == 0
            ? amount
            : (amount * totalShares) / totalAmountStaked;
        require(currentShares != 0, 'Deposit: Fail');
        // Adjust number of shares for user/total
        userInfo[msg.sender] += currentShares;
        totalShares += currentShares;
        // Deposit to FeeSharingSystem contract
        feeSharingSystem.deposit(amount, false);
        emit Deposit(msg.sender, amount);
    }
    /**
     * @notice Redeem shares for X2Y2 tokens
     * @param shares number of shares to redeem
     */
    function withdraw(uint256 shares) external nonReentrant {
        require(
            (shares > 0) && (shares <= userInfo[msg.sender]),
            'Withdraw: Shares equal to 0 or larger than user shares'
        );
        _withdraw(shares);
    }
    /**
     * @notice Withdraw all shares of sender
     */
    function withdrawAll() external nonReentrant {
        require(userInfo[msg.sender] > 0, 'Withdraw: Shares equal to 0');
        _withdraw(userInfo[msg.sender]);
    }
    /**
     * @notice Harvest pending WETH, sell them to X2Y2, and deposit X2Y2 (if possible)
     * @dev Only callable by owner.
     */
    function harvestAndSellAndCompound() external nonReentrant onlyOwner {
        require(totalShares != 0, 'Harvest: No share');
        require(block.number != lastHarvestBlock, 'Harvest: Already done');
        _harvestAndSellAndCompound();
    }
    /**
     * @notice Adjust allowance if necessary
     * @dev Only callable by owner.
     */
    function checkAndAdjustX2Y2TokenAllowanceIfRequired() external onlyOwner {
        x2y2Token.approve(address(feeSharingSystem), type(uint256).max);
    }
    /**
     * @notice Adjust allowance if necessary
     * @dev Only callable by owner.
     */
    function checkAndAdjustRewardTokenAllowanceIfRequired() external onlyOwner {
        rewardToken.approve(address(uniswapRouter), type(uint256).max);
    }
    /**
     * @notice Update harvest buffer block
     * @param _newHarvestBufferBlocks buffer in blocks between two harvest operations
     * @dev Only callable by owner.
     */
    function updateHarvestBufferBlocks(uint256 _newHarvestBufferBlocks) external onlyOwner {
        require(
            _newHarvestBufferBlocks <= MAXIMUM_HARVEST_BUFFER_BLOCKS,
            'Owner: Must be below MAXIMUM_HARVEST_BUFFER_BLOCKS'
        );
        harvestBufferBlocks = _newHarvestBufferBlocks;
        emit NewHarvestBufferBlocks(_newHarvestBufferBlocks);
    }
    /**
     * @notice Start automatic harvest/selling transactions
     * @dev Only callable by owner
     */
    function startHarvest() external onlyOwner {
        canHarvest = true;
        emit HarvestStart();
    }
    /**
     * @notice Stop automatic harvest transactions
     * @dev Only callable by owner
     */
    function stopHarvest() external onlyOwner {
        canHarvest = false;
        emit HarvestStop();
    }
    /**
     * @notice Update maximum price of X2Y2 in WETH
     * @param _newMaxPriceX2Y2InWETH new maximum price of X2Y2 in WETH times 1e18
     * @dev Only callable by owner
     */
    function updateMaxPriceOfX2Y2InWETH(uint256 _newMaxPriceX2Y2InWETH) external onlyOwner {
        maxPriceX2Y2InWETH = _newMaxPriceX2Y2InWETH;
        emit NewMaximumPriceX2Y2InWETH(_newMaxPriceX2Y2InWETH);
    }
    /**
     * @notice Adjust threshold amount for periodic Uniswap v3 WETH --> X2Y2 conversion
     * @param _newThresholdAmount new threshold amount (in WETH)
     * @dev Only callable by owner
     */
    function updateThresholdAmount(uint256 _newThresholdAmount) external onlyOwner {
        thresholdAmount = _newThresholdAmount;
        emit NewThresholdAmount(_newThresholdAmount);
    }
    /**
     * @notice Pause
     * @dev Only callable by owner
     */
    function pause() external onlyOwner whenNotPaused {
        _pause();
    }
    /**
     * @notice Unpause
     * @dev Only callable by owner
     */
    function unpause() external onlyOwner whenPaused {
        _unpause();
    }
    /**
     * @notice Calculate price of one share (in X2Y2 token)
     * Share price is expressed times 1e18
     */
    function calculateSharePriceInX2Y2() external view returns (uint256) {
        uint256 totalAmountStakedWithAggregator = feeSharingSystem.calculateSharesValueInX2Y2(
            address(this)
        );
        return
            totalShares == 0
                ? MINIMUM_DEPOSIT_X2Y2
                : (totalAmountStakedWithAggregator * MINIMUM_DEPOSIT_X2Y2) / (totalShares);
    }
    /**
     * @notice Calculate price of one share (in prime share)
     * Share price is expressed times 1e18
     */
    function calculateSharePriceInPrimeShare() external view returns (uint256) {
        (uint256 totalNumberPrimeShares, , ) = feeSharingSystem.userInfo(address(this));
        return
            totalShares == 0
                ? MINIMUM_DEPOSIT_X2Y2
                : (totalNumberPrimeShares * MINIMUM_DEPOSIT_X2Y2) / totalShares;
    }
    /**
     * @notice Calculate shares value of a user (in X2Y2)
     * @param user address of the user
     */
    function calculateSharesValueInX2Y2(address user) external view returns (uint256) {
        uint256 totalAmountStakedWithAggregator = feeSharingSystem.calculateSharesValueInX2Y2(
            address(this)
        );
        return
            totalShares == 0 ? 0 : (totalAmountStakedWithAggregator * userInfo[user]) / totalShares;
    }
    /**
     * @notice Harvest pending WETH, sell them to X2Y2, and deposit X2Y2 (if possible)
     */
    function _harvestAndSellAndCompound() internal {
        // Try/catch to prevent revertions if nothing to harvest
        try feeSharingSystem.harvest() {} catch {}
        uint256 amountToSell = rewardToken.balanceOf(address(this));
        if (amountToSell >= thresholdAmount) {
            bool isExecuted = _sellRewardTokenToX2Y2(amountToSell);
            if (isExecuted) {
                uint256 adjustedAmount = x2y2Token.balanceOf(address(this));
                if (adjustedAmount >= MINIMUM_DEPOSIT_X2Y2) {
                    feeSharingSystem.deposit(adjustedAmount, false);
                }
            }
        }
        // Adjust last harvest block
        lastHarvestBlock = block.number;
    }
    /**
     * @notice Sell WETH to X2Y2
     * @param _amount amount of rewardToken to convert (WETH)
     * @return whether the transaction went through
     */
    function _sellRewardTokenToX2Y2(uint256 _amount) internal returns (bool) {
        uint256 minAmountOut = 0;
        if (maxPriceX2Y2InWETH > 0) {
            minAmountOut = (_amount * 1e18) / maxPriceX2Y2InWETH;
        }
        address[] memory path = new address[](2);
        path[0] = address(rewardToken);
        path[1] = address(x2y2Token);
        try
            uniswapRouter.swapExactTokensForTokens(
                _amount, // amountIn
                minAmountOut, // amountOutMin
                path, // path
                address(this), // to
                block.timestamp // deadline
            )
        returns (uint256[] memory amounts) {
            emit ConversionToX2Y2(amounts[0], amounts[1]);
            return true;
        } catch {
            emit FailedConversion();
            return false;
        }
        return false;
    }
    /**
     * @notice Withdraw shares
     * @param _shares number of shares to redeem
     * @dev The difference between the two snapshots of X2Y2 balances is used to know how many tokens to transfer to user.
     */
    function _withdraw(uint256 _shares) internal {
        if (block.number > (lastHarvestBlock + harvestBufferBlocks) && canHarvest) {
            _harvestAndSellAndCompound();
        }
        // Take snapshot of current X2Y2 balance
        uint256 previousBalanceX2Y2 = x2y2Token.balanceOf(address(this));
        // Fetch total number of prime shares
        (uint256 totalNumberPrimeShares, , ) = feeSharingSystem.userInfo(address(this));
        // Calculate number of prime shares to redeem based on existing shares (from this contract)
        uint256 currentNumberPrimeShares = (totalNumberPrimeShares * _shares) / totalShares;
        // Adjust number of shares for user/total
        userInfo[msg.sender] -= _shares;
        totalShares -= _shares;
        // Withdraw amount equivalent in prime shares
        feeSharingSystem.withdraw(currentNumberPrimeShares, false);
        // Calculate the difference between the current balance of X2Y2 with the previous snapshot
        uint256 amountToTransfer = x2y2Token.balanceOf(address(this)) - previousBalanceX2Y2;
        // Transfer the x2y2 amount back to user
        x2y2Token.safeTransfer(msg.sender, amountToTransfer);
        emit Withdraw(msg.sender, amountToTransfer);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../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.
 *
 * By default, the owner account will be the one that deploys the contract. 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;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }
    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }
    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }
    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing 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 {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _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 v4.4.1 (security/Pausable.sol)
pragma solidity ^0.8.0;
import "../utils/Context.sol";
/**
 * @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 Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }
    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!paused(), "Pausable: paused");
        _;
    }
    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        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());
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
        _;
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;
    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }
    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }
    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.
        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}
pragma solidity >=0.6.2;
import './IUniswapV2Router01.sol';
interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountETH);
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {AccessControl} from '@openzeppelin/contracts/access/AccessControl.sol';
import {IERC20, SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
import {ReentrancyGuard} from '@openzeppelin/contracts/security/ReentrancyGuard.sol';
import {TokenDistributor} from './TokenDistributor.sol';
import {IStakeFor} from './IStakeFor.sol';
/**
 * @title FeeSharingSystem
 * @notice It handles the distribution of fees using
 * WETH along with the auto-compounding of X2Y2.
 */
contract FeeSharingSystem is ReentrancyGuard, AccessControl, IStakeFor {
    using SafeERC20 for IERC20;
    // for `depositFor` call
    bytes32 public constant DEPOSIT_ROLE = keccak256('DEPOSIT_ROLE');
    // for `updateRewards()`
    bytes32 public constant REWARD_UPDATE_ROLE = keccak256('REWARD_UPDATE_ROLE');
    struct UserInfo {
        uint256 shares; // shares of token staked
        uint256 userRewardPerTokenPaid; // user reward per token paid
        uint256 rewards; // pending rewards
    }
    // Precision factor for calculating rewards and exchange rate
    uint256 public constant PRECISION_FACTOR = 10**18;
    IERC20 public immutable x2y2Token;
    IERC20 public immutable rewardToken;
    TokenDistributor public immutable tokenDistributor;
    // Reward rate (block)
    uint256 public currentRewardPerBlock;
    // Last reward adjustment block number
    uint256 public lastRewardAdjustment;
    // Last update block for rewards
    uint256 public lastUpdateBlock;
    // Current end block for the current reward period
    uint256 public periodEndBlock;
    // Reward per token stored
    uint256 public rewardPerTokenStored;
    // Total existing shares
    uint256 public totalShares;
    mapping(address => UserInfo) public userInfo;
    event Deposit(address indexed user, uint256 amount, uint256 harvestedAmount);
    event Harvest(address indexed user, uint256 harvestedAmount);
    event NewRewardPeriod(uint256 numberBlocks, uint256 rewardPerBlock, uint256 reward);
    event Withdraw(address indexed user, uint256 amount, uint256 harvestedAmount);
    /**
     * @notice Constructor
     * @param _x2y2Token address of the token staked
     * @param _rewardToken address of the reward token
     * @param _tokenDistributor address of the token distributor contract
     */
    constructor(
        address _x2y2Token,
        address _rewardToken,
        address _tokenDistributor
    ) {
        rewardToken = IERC20(_rewardToken);
        x2y2Token = IERC20(_x2y2Token);
        tokenDistributor = TokenDistributor(_tokenDistributor);
        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
    }
    /**
     * @notice deposit on behalf of `user`, must be called on fresh deposit only
     * @param user deposit user
     * @param amount amount to deposit
     */
    function depositFor(address user, uint256 amount)
        external
        override
        nonReentrant
        onlyRole(DEPOSIT_ROLE)
        returns (bool)
    {
        require(amount >= PRECISION_FACTOR, 'Deposit: Amount must be >= 1 X2Y2');
        // Auto compounds for everyone
        tokenDistributor.harvestAndCompound();
        // Update reward for user
        _updateReward(user);
        // Retrieve total amount staked by this contract
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        // transfer stakingToken from **sender**
        x2y2Token.safeTransferFrom(msg.sender, address(this), amount);
        uint256 currentShares;
        // Calculate the number of shares to issue for the user
        if (totalShares != 0) {
            currentShares = (amount * totalShares) / totalAmountStaked;
            // This is a sanity check to prevent deposit for 0 shares
            require(currentShares != 0, 'Deposit: Fail');
        } else {
            currentShares = amount;
        }
        // Adjust internal shares
        userInfo[user].shares += currentShares;
        totalShares += currentShares;
        // Verify X2Y2 token allowance and adjust if necessary
        _checkAndAdjustX2Y2TokenAllowanceIfRequired(amount, address(tokenDistributor));
        // Deposit user amount in the token distributor contract
        tokenDistributor.deposit(amount);
        emit Deposit(user, amount, 0);
        return true;
    }
    /**
     * @notice Deposit staked tokens (and collect reward tokens if requested)
     * @param amount amount to deposit (in X2Y2)
     * @param claimRewardToken whether to claim reward tokens
     * @dev There is a limit of 1 X2Y2 per deposit to prevent potential manipulation of current shares
     */
    function deposit(uint256 amount, bool claimRewardToken) external nonReentrant {
        require(amount >= PRECISION_FACTOR, 'Deposit: Amount must be >= 1 X2Y2');
        // Auto compounds for everyone
        tokenDistributor.harvestAndCompound();
        // Update reward for user
        _updateReward(msg.sender);
        // Retrieve total amount staked by this contract
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        // Transfer X2Y2 tokens to this address
        x2y2Token.safeTransferFrom(msg.sender, address(this), amount);
        uint256 currentShares;
        // Calculate the number of shares to issue for the user
        if (totalShares != 0) {
            currentShares = (amount * totalShares) / totalAmountStaked;
            // This is a sanity check to prevent deposit for 0 shares
            require(currentShares != 0, 'Deposit: Fail');
        } else {
            currentShares = amount;
        }
        // Adjust internal shares
        userInfo[msg.sender].shares += currentShares;
        totalShares += currentShares;
        uint256 pendingRewards;
        if (claimRewardToken) {
            // Fetch pending rewards
            pendingRewards = userInfo[msg.sender].rewards;
            if (pendingRewards > 0) {
                userInfo[msg.sender].rewards = 0;
                rewardToken.safeTransfer(msg.sender, pendingRewards);
            }
        }
        // Verify X2Y2 token allowance and adjust if necessary
        _checkAndAdjustX2Y2TokenAllowanceIfRequired(amount, address(tokenDistributor));
        // Deposit user amount in the token distributor contract
        tokenDistributor.deposit(amount);
        emit Deposit(msg.sender, amount, pendingRewards);
    }
    /**
     * @notice Harvest reward tokens that are pending
     */
    function harvest() external nonReentrant {
        // Auto compounds for everyone
        tokenDistributor.harvestAndCompound();
        // Update reward for user
        _updateReward(msg.sender);
        // Retrieve pending rewards
        uint256 pendingRewards = userInfo[msg.sender].rewards;
        // If pending rewards are null, revert
        require(pendingRewards > 0, 'Harvest: Pending rewards must be > 0');
        // Adjust user rewards and transfer
        userInfo[msg.sender].rewards = 0;
        // Transfer reward token to sender
        rewardToken.safeTransfer(msg.sender, pendingRewards);
        emit Harvest(msg.sender, pendingRewards);
    }
    /**
     * @notice Withdraw staked tokens (and collect reward tokens if requested)
     * @param shares shares to withdraw
     * @param claimRewardToken whether to claim reward tokens
     */
    function withdraw(uint256 shares, bool claimRewardToken) external nonReentrant {
        require(
            (shares > 0) && (shares <= userInfo[msg.sender].shares),
            'Withdraw: Shares equal to 0 or larger than user shares'
        );
        _withdraw(shares, claimRewardToken);
    }
    /**
     * @notice Withdraw all staked tokens (and collect reward tokens if requested)
     * @param claimRewardToken whether to claim reward tokens
     */
    function withdrawAll(bool claimRewardToken) external nonReentrant {
        _withdraw(userInfo[msg.sender].shares, claimRewardToken);
    }
    /**
     * @notice Update the reward per block (in rewardToken)
     * @dev Only callable by owner. Owner is meant to be another smart contract.
     */
    function updateRewards(uint256 reward, uint256 rewardDurationInBlocks)
        external
        onlyRole(REWARD_UPDATE_ROLE)
    {
        // Adjust the current reward per block
        if (block.number >= periodEndBlock) {
            currentRewardPerBlock = reward / rewardDurationInBlocks;
        } else {
            currentRewardPerBlock =
                (reward + ((periodEndBlock - block.number) * currentRewardPerBlock)) /
                rewardDurationInBlocks;
        }
        lastUpdateBlock = block.number;
        periodEndBlock = block.number + rewardDurationInBlocks;
        emit NewRewardPeriod(rewardDurationInBlocks, currentRewardPerBlock, reward);
    }
    /**
     * @notice Calculate pending rewards (WETH) for a user
     * @param user address of the user
     */
    function calculatePendingRewards(address user) external view returns (uint256) {
        return _calculatePendingRewards(user);
    }
    /**
     * @notice Calculate value of X2Y2 for a user given a number of shares owned
     * @param user address of the user
     */
    function calculateSharesValueInX2Y2(address user) external view returns (uint256) {
        // Retrieve amount staked
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        // Adjust for pending rewards
        totalAmountStaked += tokenDistributor.calculatePendingRewards(address(this));
        // Return user pro-rata of total shares
        return
            userInfo[user].shares == 0
                ? 0
                : (totalAmountStaked * userInfo[user].shares) / totalShares;
    }
    /**
     * @notice Calculate price of one share (in X2Y2 token)
     * Share price is expressed times 1e18
     */
    function calculateSharePriceInX2Y2() external view returns (uint256) {
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        // Adjust for pending rewards
        totalAmountStaked += tokenDistributor.calculatePendingRewards(address(this));
        return
            totalShares == 0
                ? PRECISION_FACTOR
                : (totalAmountStaked * PRECISION_FACTOR) / (totalShares);
    }
    /**
     * @notice Return last block where trading rewards were distributed
     */
    function lastRewardBlock() external view returns (uint256) {
        return _lastRewardBlock();
    }
    /**
     * @notice Calculate pending rewards for a user
     * @param user address of the user
     */
    function _calculatePendingRewards(address user) internal view returns (uint256) {
        return
            ((userInfo[user].shares *
                (_rewardPerToken() - (userInfo[user].userRewardPerTokenPaid))) / PRECISION_FACTOR) +
            userInfo[user].rewards;
    }
    /**
     * @notice Check current allowance and adjust if necessary
     * @param _amount amount to transfer
     * @param _to token to transfer
     */
    function _checkAndAdjustX2Y2TokenAllowanceIfRequired(uint256 _amount, address _to) internal {
        if (x2y2Token.allowance(address(this), _to) < _amount) {
            x2y2Token.approve(_to, type(uint256).max);
        }
    }
    /**
     * @notice Return last block where rewards must be distributed
     */
    function _lastRewardBlock() internal view returns (uint256) {
        return block.number < periodEndBlock ? block.number : periodEndBlock;
    }
    /**
     * @notice Return reward per token
     */
    function _rewardPerToken() internal view returns (uint256) {
        if (totalShares == 0) {
            return rewardPerTokenStored;
        }
        return
            rewardPerTokenStored +
            ((_lastRewardBlock() - lastUpdateBlock) * (currentRewardPerBlock * PRECISION_FACTOR)) /
            totalShares;
    }
    /**
     * @notice Update reward for a user account
     * @param _user address of the user
     */
    function _updateReward(address _user) internal {
        if (block.number != lastUpdateBlock) {
            rewardPerTokenStored = _rewardPerToken();
            lastUpdateBlock = _lastRewardBlock();
        }
        userInfo[_user].rewards = _calculatePendingRewards(_user);
        userInfo[_user].userRewardPerTokenPaid = rewardPerTokenStored;
    }
    /**
     * @notice Withdraw staked tokens (and collect reward tokens if requested)
     * @param shares shares to withdraw
     * @param claimRewardToken whether to claim reward tokens
     */
    function _withdraw(uint256 shares, bool claimRewardToken) internal {
        // Auto compounds for everyone
        tokenDistributor.harvestAndCompound();
        // Update reward for user
        _updateReward(msg.sender);
        // Retrieve total amount staked and calculated current amount (in X2Y2)
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        uint256 currentAmount = (totalAmountStaked * shares) / totalShares;
        userInfo[msg.sender].shares -= shares;
        totalShares -= shares;
        // Withdraw amount equivalent in shares
        tokenDistributor.withdraw(currentAmount);
        uint256 pendingRewards;
        if (claimRewardToken) {
            // Fetch pending rewards
            pendingRewards = userInfo[msg.sender].rewards;
            if (pendingRewards > 0) {
                userInfo[msg.sender].rewards = 0;
                rewardToken.safeTransfer(msg.sender, pendingRewards);
            }
        }
        // Transfer X2Y2 tokens to sender
        x2y2Token.safeTransfer(msg.sender, currentAmount);
        emit Withdraw(msg.sender, currentAmount, pendingRewards);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
 * @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;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) 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 `amount` 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 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
    /**
     * @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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
pragma solidity ^0.8.0;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }
    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
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,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );
    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountA, uint256 amountB);
    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountToken, uint256 amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH);
    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);
    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);
    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) external pure returns (uint256 amountB);
    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountOut);
    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountIn);
    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
    function getAmountsIn(uint256 amountOut, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/AccessControl.sol)
pragma solidity ^0.8.0;
import "./IAccessControl.sol";
import "../utils/Context.sol";
import "../utils/Strings.sol";
import "../utils/introspection/ERC165.sol";
/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }
    mapping(bytes32 => RoleData) private _roles;
    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;
    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role, _msgSender());
        _;
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControl).interfaceId || super.supportsInterface(interfaceId);
    }
    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view override returns (bool) {
        return _roles[role].members[account];
    }
    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        Strings.toHexString(uint160(account), 20),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }
    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view override returns (bytes32) {
        return _roles[role].adminRole;
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }
    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }
    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been revoked `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual override {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");
        _revokeRole(role, account);
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     *
     * NOTE: This function is deprecated in favor of {_grantRole}.
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }
    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * Internal function without access restriction.
     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }
    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {ReentrancyGuard} from '@openzeppelin/contracts/security/ReentrancyGuard.sol';
import {IERC20, SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
import {IMintableERC20} from './IMintableERC20.sol';
/**
 * @title TokenDistributor
 * @notice It handles the distribution of X2Y2 token.
 * It auto-adjusts block rewards over a set number of periods.
 */
contract TokenDistributor is ReentrancyGuard {
    using SafeERC20 for IERC20;
    using SafeERC20 for IMintableERC20;
    struct StakingPeriod {
        uint256 rewardPerBlockForStaking;
        uint256 rewardPerBlockForOthers;
        uint256 periodLengthInBlock;
    }
    struct UserInfo {
        uint256 amount; // Amount of staked tokens provided by user
        uint256 rewardDebt; // Reward debt
    }
    // Precision factor for calculating rewards
    uint256 public constant PRECISION_FACTOR = 10**12;
    IMintableERC20 public immutable x2y2Token;
    address public immutable tokenSplitter;
    // Number of reward periods
    uint256 public immutable NUMBER_PERIODS;
    // Block number when rewards start
    uint256 public immutable START_BLOCK;
    // Accumulated tokens per share
    uint256 public accTokenPerShare;
    // Current phase for rewards
    uint256 public currentPhase;
    // Block number when rewards end
    uint256 public endBlock;
    // Block number of the last update
    uint256 public lastRewardBlock;
    // Tokens distributed per block for other purposes (team + treasury + trading rewards)
    uint256 public rewardPerBlockForOthers;
    // Tokens distributed per block for staking
    uint256 public rewardPerBlockForStaking;
    // Total amount staked
    uint256 public totalAmountStaked;
    mapping(uint256 => StakingPeriod) public stakingPeriod;
    mapping(address => UserInfo) public userInfo;
    event Compound(address indexed user, uint256 harvestedAmount);
    event Deposit(address indexed user, uint256 amount, uint256 harvestedAmount);
    event NewRewardsPerBlock(
        uint256 indexed currentPhase,
        uint256 startBlock,
        uint256 rewardPerBlockForStaking,
        uint256 rewardPerBlockForOthers
    );
    event Withdraw(address indexed user, uint256 amount, uint256 harvestedAmount);
    /**
     * @notice Constructor
     * @param _x2y2Token token address
     * @param _tokenSplitter token splitter contract address (for team and trading rewards)
     * @param _startBlock start block for reward program
     * @param _rewardsPerBlockForStaking array of rewards per block for staking
     * @param _rewardsPerBlockForOthers array of rewards per block for other purposes (team + treasury + trading rewards)
     * @param _periodLengthesInBlocks array of period lengthes
     * @param _numberPeriods number of periods with different rewards/lengthes (e.g., if 3 changes --> 4 periods)
     */
    constructor(
        address _x2y2Token,
        address _tokenSplitter,
        uint256 _startBlock,
        uint256[] memory _rewardsPerBlockForStaking,
        uint256[] memory _rewardsPerBlockForOthers,
        uint256[] memory _periodLengthesInBlocks,
        uint256 _numberPeriods
    ) {
        require(
            (_periodLengthesInBlocks.length == _numberPeriods) &&
                (_rewardsPerBlockForStaking.length == _numberPeriods) &&
                (_rewardsPerBlockForStaking.length == _numberPeriods),
            'Distributor: Lengthes must match numberPeriods'
        );
        // 1. Operational checks for supply
        uint256 nonCirculatingSupply = IMintableERC20(_x2y2Token).SUPPLY_CAP() -
            IMintableERC20(_x2y2Token).totalSupply();
        uint256 amountTokensToBeMinted;
        for (uint256 i = 0; i < _numberPeriods; i++) {
            amountTokensToBeMinted +=
                (_rewardsPerBlockForStaking[i] * _periodLengthesInBlocks[i]) +
                (_rewardsPerBlockForOthers[i] * _periodLengthesInBlocks[i]);
            stakingPeriod[i] = StakingPeriod({
                rewardPerBlockForStaking: _rewardsPerBlockForStaking[i],
                rewardPerBlockForOthers: _rewardsPerBlockForOthers[i],
                periodLengthInBlock: _periodLengthesInBlocks[i]
            });
        }
        require(
            amountTokensToBeMinted == nonCirculatingSupply,
            'Distributor: Wrong reward parameters'
        );
        // 2. Store values
        x2y2Token = IMintableERC20(_x2y2Token);
        tokenSplitter = _tokenSplitter;
        rewardPerBlockForStaking = _rewardsPerBlockForStaking[0];
        rewardPerBlockForOthers = _rewardsPerBlockForOthers[0];
        START_BLOCK = _startBlock;
        endBlock = _startBlock + _periodLengthesInBlocks[0];
        NUMBER_PERIODS = _numberPeriods;
        // Set the lastRewardBlock as the startBlock
        lastRewardBlock = _startBlock;
    }
    /**
     * @notice Deposit staked tokens and compounds pending rewards
     * @param amount amount to deposit (in X2Y2)
     */
    function deposit(uint256 amount) external nonReentrant {
        require(amount > 0, 'Deposit: Amount must be > 0');
        require(block.number >= START_BLOCK, 'Deposit: Not started yet');
        // Update pool information
        _updatePool();
        // Transfer X2Y2 tokens to this contract
        x2y2Token.safeTransferFrom(msg.sender, address(this), amount);
        uint256 pendingRewards;
        // If not new deposit, calculate pending rewards (for auto-compounding)
        if (userInfo[msg.sender].amount > 0) {
            pendingRewards =
                ((userInfo[msg.sender].amount * accTokenPerShare) / PRECISION_FACTOR) -
                userInfo[msg.sender].rewardDebt;
        }
        // Adjust user information
        userInfo[msg.sender].amount += (amount + pendingRewards);
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        // Increase totalAmountStaked
        totalAmountStaked += (amount + pendingRewards);
        emit Deposit(msg.sender, amount, pendingRewards);
    }
    /**
     * @notice Compound based on pending rewards
     */
    function harvestAndCompound() external nonReentrant {
        // Update pool information
        _updatePool();
        // Calculate pending rewards
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        // Return if no pending rewards
        if (pendingRewards == 0) {
            // It doesn't throw revertion (to help with the fee-sharing auto-compounding contract)
            return;
        }
        // Adjust user amount for pending rewards
        userInfo[msg.sender].amount += pendingRewards;
        // Adjust totalAmountStaked
        totalAmountStaked += pendingRewards;
        // Recalculate reward debt based on new user amount
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        emit Compound(msg.sender, pendingRewards);
    }
    /**
     * @notice Update pool rewards
     */
    function updatePool() external nonReentrant {
        _updatePool();
    }
    /**
     * @notice Withdraw staked tokens and compound pending rewards
     * @param amount amount to withdraw
     */
    function withdraw(uint256 amount) external nonReentrant {
        require(
            (userInfo[msg.sender].amount >= amount) && (amount > 0),
            'Withdraw: Amount must be > 0 or lower than user balance'
        );
        // Update pool
        _updatePool();
        // Calculate pending rewards
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        // Adjust user information
        userInfo[msg.sender].amount = userInfo[msg.sender].amount + pendingRewards - amount;
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        // Adjust total amount staked
        totalAmountStaked = totalAmountStaked + pendingRewards - amount;
        // Transfer X2Y2 tokens to the sender
        x2y2Token.safeTransfer(msg.sender, amount);
        emit Withdraw(msg.sender, amount, pendingRewards);
    }
    /**
     * @notice Withdraw all staked tokens and collect tokens
     */
    function withdrawAll() external nonReentrant {
        require(userInfo[msg.sender].amount > 0, 'Withdraw: Amount must be > 0');
        // Update pool
        _updatePool();
        // Calculate pending rewards and amount to transfer (to the sender)
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        uint256 amountToTransfer = userInfo[msg.sender].amount + pendingRewards;
        // Adjust total amount staked
        totalAmountStaked = totalAmountStaked - userInfo[msg.sender].amount;
        // Adjust user information
        userInfo[msg.sender].amount = 0;
        userInfo[msg.sender].rewardDebt = 0;
        // Transfer X2Y2 tokens to the sender
        x2y2Token.safeTransfer(msg.sender, amountToTransfer);
        emit Withdraw(msg.sender, amountToTransfer, pendingRewards);
    }
    /**
     * @notice Calculate pending rewards for a user
     * @param user address of the user
     * @return Pending rewards
     */
    function calculatePendingRewards(address user) external view returns (uint256) {
        if ((block.number > lastRewardBlock) && (totalAmountStaked != 0)) {
            uint256 multiplier = _getMultiplier(lastRewardBlock, block.number);
            uint256 tokenRewardForStaking = multiplier * rewardPerBlockForStaking;
            uint256 adjustedEndBlock = endBlock;
            uint256 adjustedCurrentPhase = currentPhase;
            // Check whether to adjust multipliers and reward per block
            while (
                (block.number > adjustedEndBlock) && (adjustedCurrentPhase < (NUMBER_PERIODS - 1))
            ) {
                // Update current phase
                adjustedCurrentPhase++;
                // Update rewards per block
                uint256 adjustedRewardPerBlockForStaking = stakingPeriod[adjustedCurrentPhase]
                    .rewardPerBlockForStaking;
                // Calculate adjusted block number
                uint256 previousEndBlock = adjustedEndBlock;
                // Update end block
                adjustedEndBlock =
                    previousEndBlock +
                    stakingPeriod[adjustedCurrentPhase].periodLengthInBlock;
                // Calculate new multiplier
                uint256 newMultiplier = (block.number <= adjustedEndBlock)
                    ? (block.number - previousEndBlock)
                    : stakingPeriod[adjustedCurrentPhase].periodLengthInBlock;
                // Adjust token rewards for staking
                tokenRewardForStaking += (newMultiplier * adjustedRewardPerBlockForStaking);
            }
            uint256 adjustedTokenPerShare = accTokenPerShare +
                (tokenRewardForStaking * PRECISION_FACTOR) /
                totalAmountStaked;
            return
                (userInfo[user].amount * adjustedTokenPerShare) /
                PRECISION_FACTOR -
                userInfo[user].rewardDebt;
        } else {
            return
                (userInfo[user].amount * accTokenPerShare) /
                PRECISION_FACTOR -
                userInfo[user].rewardDebt;
        }
    }
    /**
     * @notice Update reward variables of the pool
     */
    function _updatePool() internal {
        if (block.number <= lastRewardBlock) {
            return;
        }
        if (totalAmountStaked == 0) {
            lastRewardBlock = block.number;
            return;
        }
        // Calculate multiplier
        uint256 multiplier = _getMultiplier(lastRewardBlock, block.number);
        // Calculate rewards for staking and others
        uint256 tokenRewardForStaking = multiplier * rewardPerBlockForStaking;
        uint256 tokenRewardForOthers = multiplier * rewardPerBlockForOthers;
        // Check whether to adjust multipliers and reward per block
        while ((block.number > endBlock) && (currentPhase < (NUMBER_PERIODS - 1))) {
            // Update rewards per block
            _updateRewardsPerBlock(endBlock);
            uint256 previousEndBlock = endBlock;
            // Adjust the end block
            endBlock += stakingPeriod[currentPhase].periodLengthInBlock;
            // Adjust multiplier to cover the missing periods with other lower inflation schedule
            uint256 newMultiplier = _getMultiplier(previousEndBlock, block.number);
            // Adjust token rewards
            tokenRewardForStaking += (newMultiplier * rewardPerBlockForStaking);
            tokenRewardForOthers += (newMultiplier * rewardPerBlockForOthers);
        }
        // Mint tokens only if token rewards for staking are not null
        if (tokenRewardForStaking > 0) {
            // It allows protection against potential issues to prevent funds from being locked
            bool mintStatus = x2y2Token.mint(address(this), tokenRewardForStaking);
            if (mintStatus) {
                accTokenPerShare =
                    accTokenPerShare +
                    ((tokenRewardForStaking * PRECISION_FACTOR) / totalAmountStaked);
            }
            x2y2Token.mint(tokenSplitter, tokenRewardForOthers);
        }
        // Update last reward block only if it wasn't updated after or at the end block
        if (lastRewardBlock <= endBlock) {
            lastRewardBlock = block.number;
        }
    }
    /**
     * @notice Update rewards per block
     * @dev Rewards are halved by 2 (for staking + others)
     */
    function _updateRewardsPerBlock(uint256 _newStartBlock) internal {
        // Update current phase
        currentPhase++;
        // Update rewards per block
        rewardPerBlockForStaking = stakingPeriod[currentPhase].rewardPerBlockForStaking;
        rewardPerBlockForOthers = stakingPeriod[currentPhase].rewardPerBlockForOthers;
        emit NewRewardsPerBlock(
            currentPhase,
            _newStartBlock,
            rewardPerBlockForStaking,
            rewardPerBlockForOthers
        );
    }
    /**
     * @notice Return reward multiplier over the given "from" to "to" block.
     * @param from block to start calculating reward
     * @param to block to finish calculating reward
     * @return the multiplier for the period
     */
    function _getMultiplier(uint256 from, uint256 to) internal view returns (uint256) {
        if (to <= endBlock) {
            return to - from;
        } else if (from >= endBlock) {
            return 0;
        } else {
            return endBlock - from;
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface IStakeFor {
    function depositFor(address user, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)
pragma solidity ^0.8.0;
/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControl {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);
    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);
    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;
    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;
    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
pragma solidity ^0.8.0;
/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {IERC20} from '@openzeppelin/contracts/token/ERC20/IERC20.sol';
interface IMintableERC20 is IERC20 {
    function SUPPLY_CAP() external view returns (uint256);
    function mint(address account, uint256 amount) external returns (bool);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {ReentrancyGuard} from '@openzeppelin/contracts/security/ReentrancyGuard.sol';
import {IERC20, SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
import {IMintableERC20} from './IMintableERC20.sol';
/**
 * @title TokenDistributor
 * @notice It handles the distribution of X2Y2 token.
 * It auto-adjusts block rewards over a set number of periods.
 */
contract TokenDistributor is ReentrancyGuard {
    using SafeERC20 for IERC20;
    using SafeERC20 for IMintableERC20;
    struct StakingPeriod {
        uint256 rewardPerBlockForStaking;
        uint256 rewardPerBlockForOthers;
        uint256 periodLengthInBlock;
    }
    struct UserInfo {
        uint256 amount; // Amount of staked tokens provided by user
        uint256 rewardDebt; // Reward debt
    }
    // Precision factor for calculating rewards
    uint256 public constant PRECISION_FACTOR = 10**12;
    IMintableERC20 public immutable x2y2Token;
    address public immutable tokenSplitter;
    // Number of reward periods
    uint256 public immutable NUMBER_PERIODS;
    // Block number when rewards start
    uint256 public immutable START_BLOCK;
    // Accumulated tokens per share
    uint256 public accTokenPerShare;
    // Current phase for rewards
    uint256 public currentPhase;
    // Block number when rewards end
    uint256 public endBlock;
    // Block number of the last update
    uint256 public lastRewardBlock;
    // Tokens distributed per block for other purposes (team + treasury + trading rewards)
    uint256 public rewardPerBlockForOthers;
    // Tokens distributed per block for staking
    uint256 public rewardPerBlockForStaking;
    // Total amount staked
    uint256 public totalAmountStaked;
    mapping(uint256 => StakingPeriod) public stakingPeriod;
    mapping(address => UserInfo) public userInfo;
    event Compound(address indexed user, uint256 harvestedAmount);
    event Deposit(address indexed user, uint256 amount, uint256 harvestedAmount);
    event NewRewardsPerBlock(
        uint256 indexed currentPhase,
        uint256 startBlock,
        uint256 rewardPerBlockForStaking,
        uint256 rewardPerBlockForOthers
    );
    event Withdraw(address indexed user, uint256 amount, uint256 harvestedAmount);
    /**
     * @notice Constructor
     * @param _x2y2Token token address
     * @param _tokenSplitter token splitter contract address (for team and trading rewards)
     * @param _startBlock start block for reward program
     * @param _rewardsPerBlockForStaking array of rewards per block for staking
     * @param _rewardsPerBlockForOthers array of rewards per block for other purposes (team + treasury + trading rewards)
     * @param _periodLengthesInBlocks array of period lengthes
     * @param _numberPeriods number of periods with different rewards/lengthes (e.g., if 3 changes --> 4 periods)
     */
    constructor(
        address _x2y2Token,
        address _tokenSplitter,
        uint256 _startBlock,
        uint256[] memory _rewardsPerBlockForStaking,
        uint256[] memory _rewardsPerBlockForOthers,
        uint256[] memory _periodLengthesInBlocks,
        uint256 _numberPeriods
    ) {
        require(
            (_periodLengthesInBlocks.length == _numberPeriods) &&
                (_rewardsPerBlockForStaking.length == _numberPeriods) &&
                (_rewardsPerBlockForStaking.length == _numberPeriods),
            'Distributor: Lengthes must match numberPeriods'
        );
        // 1. Operational checks for supply
        uint256 nonCirculatingSupply = IMintableERC20(_x2y2Token).SUPPLY_CAP() -
            IMintableERC20(_x2y2Token).totalSupply();
        uint256 amountTokensToBeMinted;
        for (uint256 i = 0; i < _numberPeriods; i++) {
            amountTokensToBeMinted +=
                (_rewardsPerBlockForStaking[i] * _periodLengthesInBlocks[i]) +
                (_rewardsPerBlockForOthers[i] * _periodLengthesInBlocks[i]);
            stakingPeriod[i] = StakingPeriod({
                rewardPerBlockForStaking: _rewardsPerBlockForStaking[i],
                rewardPerBlockForOthers: _rewardsPerBlockForOthers[i],
                periodLengthInBlock: _periodLengthesInBlocks[i]
            });
        }
        require(
            amountTokensToBeMinted == nonCirculatingSupply,
            'Distributor: Wrong reward parameters'
        );
        // 2. Store values
        x2y2Token = IMintableERC20(_x2y2Token);
        tokenSplitter = _tokenSplitter;
        rewardPerBlockForStaking = _rewardsPerBlockForStaking[0];
        rewardPerBlockForOthers = _rewardsPerBlockForOthers[0];
        START_BLOCK = _startBlock;
        endBlock = _startBlock + _periodLengthesInBlocks[0];
        NUMBER_PERIODS = _numberPeriods;
        // Set the lastRewardBlock as the startBlock
        lastRewardBlock = _startBlock;
    }
    /**
     * @notice Deposit staked tokens and compounds pending rewards
     * @param amount amount to deposit (in X2Y2)
     */
    function deposit(uint256 amount) external nonReentrant {
        require(amount > 0, 'Deposit: Amount must be > 0');
        require(block.number >= START_BLOCK, 'Deposit: Not started yet');
        // Update pool information
        _updatePool();
        // Transfer X2Y2 tokens to this contract
        x2y2Token.safeTransferFrom(msg.sender, address(this), amount);
        uint256 pendingRewards;
        // If not new deposit, calculate pending rewards (for auto-compounding)
        if (userInfo[msg.sender].amount > 0) {
            pendingRewards =
                ((userInfo[msg.sender].amount * accTokenPerShare) / PRECISION_FACTOR) -
                userInfo[msg.sender].rewardDebt;
        }
        // Adjust user information
        userInfo[msg.sender].amount += (amount + pendingRewards);
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        // Increase totalAmountStaked
        totalAmountStaked += (amount + pendingRewards);
        emit Deposit(msg.sender, amount, pendingRewards);
    }
    /**
     * @notice Compound based on pending rewards
     */
    function harvestAndCompound() external nonReentrant {
        // Update pool information
        _updatePool();
        // Calculate pending rewards
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        // Return if no pending rewards
        if (pendingRewards == 0) {
            // It doesn't throw revertion (to help with the fee-sharing auto-compounding contract)
            return;
        }
        // Adjust user amount for pending rewards
        userInfo[msg.sender].amount += pendingRewards;
        // Adjust totalAmountStaked
        totalAmountStaked += pendingRewards;
        // Recalculate reward debt based on new user amount
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        emit Compound(msg.sender, pendingRewards);
    }
    /**
     * @notice Update pool rewards
     */
    function updatePool() external nonReentrant {
        _updatePool();
    }
    /**
     * @notice Withdraw staked tokens and compound pending rewards
     * @param amount amount to withdraw
     */
    function withdraw(uint256 amount) external nonReentrant {
        require(
            (userInfo[msg.sender].amount >= amount) && (amount > 0),
            'Withdraw: Amount must be > 0 or lower than user balance'
        );
        // Update pool
        _updatePool();
        // Calculate pending rewards
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        // Adjust user information
        userInfo[msg.sender].amount = userInfo[msg.sender].amount + pendingRewards - amount;
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        // Adjust total amount staked
        totalAmountStaked = totalAmountStaked + pendingRewards - amount;
        // Transfer X2Y2 tokens to the sender
        x2y2Token.safeTransfer(msg.sender, amount);
        emit Withdraw(msg.sender, amount, pendingRewards);
    }
    /**
     * @notice Withdraw all staked tokens and collect tokens
     */
    function withdrawAll() external nonReentrant {
        require(userInfo[msg.sender].amount > 0, 'Withdraw: Amount must be > 0');
        // Update pool
        _updatePool();
        // Calculate pending rewards and amount to transfer (to the sender)
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        uint256 amountToTransfer = userInfo[msg.sender].amount + pendingRewards;
        // Adjust total amount staked
        totalAmountStaked = totalAmountStaked - userInfo[msg.sender].amount;
        // Adjust user information
        userInfo[msg.sender].amount = 0;
        userInfo[msg.sender].rewardDebt = 0;
        // Transfer X2Y2 tokens to the sender
        x2y2Token.safeTransfer(msg.sender, amountToTransfer);
        emit Withdraw(msg.sender, amountToTransfer, pendingRewards);
    }
    /**
     * @notice Calculate pending rewards for a user
     * @param user address of the user
     * @return Pending rewards
     */
    function calculatePendingRewards(address user) external view returns (uint256) {
        if ((block.number > lastRewardBlock) && (totalAmountStaked != 0)) {
            uint256 multiplier = _getMultiplier(lastRewardBlock, block.number);
            uint256 tokenRewardForStaking = multiplier * rewardPerBlockForStaking;
            uint256 adjustedEndBlock = endBlock;
            uint256 adjustedCurrentPhase = currentPhase;
            // Check whether to adjust multipliers and reward per block
            while (
                (block.number > adjustedEndBlock) && (adjustedCurrentPhase < (NUMBER_PERIODS - 1))
            ) {
                // Update current phase
                adjustedCurrentPhase++;
                // Update rewards per block
                uint256 adjustedRewardPerBlockForStaking = stakingPeriod[adjustedCurrentPhase]
                    .rewardPerBlockForStaking;
                // Calculate adjusted block number
                uint256 previousEndBlock = adjustedEndBlock;
                // Update end block
                adjustedEndBlock =
                    previousEndBlock +
                    stakingPeriod[adjustedCurrentPhase].periodLengthInBlock;
                // Calculate new multiplier
                uint256 newMultiplier = (block.number <= adjustedEndBlock)
                    ? (block.number - previousEndBlock)
                    : stakingPeriod[adjustedCurrentPhase].periodLengthInBlock;
                // Adjust token rewards for staking
                tokenRewardForStaking += (newMultiplier * adjustedRewardPerBlockForStaking);
            }
            uint256 adjustedTokenPerShare = accTokenPerShare +
                (tokenRewardForStaking * PRECISION_FACTOR) /
                totalAmountStaked;
            return
                (userInfo[user].amount * adjustedTokenPerShare) /
                PRECISION_FACTOR -
                userInfo[user].rewardDebt;
        } else {
            return
                (userInfo[user].amount * accTokenPerShare) /
                PRECISION_FACTOR -
                userInfo[user].rewardDebt;
        }
    }
    /**
     * @notice Update reward variables of the pool
     */
    function _updatePool() internal {
        if (block.number <= lastRewardBlock) {
            return;
        }
        if (totalAmountStaked == 0) {
            lastRewardBlock = block.number;
            return;
        }
        // Calculate multiplier
        uint256 multiplier = _getMultiplier(lastRewardBlock, block.number);
        // Calculate rewards for staking and others
        uint256 tokenRewardForStaking = multiplier * rewardPerBlockForStaking;
        uint256 tokenRewardForOthers = multiplier * rewardPerBlockForOthers;
        // Check whether to adjust multipliers and reward per block
        while ((block.number > endBlock) && (currentPhase < (NUMBER_PERIODS - 1))) {
            // Update rewards per block
            _updateRewardsPerBlock(endBlock);
            uint256 previousEndBlock = endBlock;
            // Adjust the end block
            endBlock += stakingPeriod[currentPhase].periodLengthInBlock;
            // Adjust multiplier to cover the missing periods with other lower inflation schedule
            uint256 newMultiplier = _getMultiplier(previousEndBlock, block.number);
            // Adjust token rewards
            tokenRewardForStaking += (newMultiplier * rewardPerBlockForStaking);
            tokenRewardForOthers += (newMultiplier * rewardPerBlockForOthers);
        }
        // Mint tokens only if token rewards for staking are not null
        if (tokenRewardForStaking > 0) {
            // It allows protection against potential issues to prevent funds from being locked
            bool mintStatus = x2y2Token.mint(address(this), tokenRewardForStaking);
            if (mintStatus) {
                accTokenPerShare =
                    accTokenPerShare +
                    ((tokenRewardForStaking * PRECISION_FACTOR) / totalAmountStaked);
            }
            x2y2Token.mint(tokenSplitter, tokenRewardForOthers);
        }
        // Update last reward block only if it wasn't updated after or at the end block
        if (lastRewardBlock <= endBlock) {
            lastRewardBlock = block.number;
        }
    }
    /**
     * @notice Update rewards per block
     * @dev Rewards are halved by 2 (for staking + others)
     */
    function _updateRewardsPerBlock(uint256 _newStartBlock) internal {
        // Update current phase
        currentPhase++;
        // Update rewards per block
        rewardPerBlockForStaking = stakingPeriod[currentPhase].rewardPerBlockForStaking;
        rewardPerBlockForOthers = stakingPeriod[currentPhase].rewardPerBlockForOthers;
        emit NewRewardsPerBlock(
            currentPhase,
            _newStartBlock,
            rewardPerBlockForStaking,
            rewardPerBlockForOthers
        );
    }
    /**
     * @notice Return reward multiplier over the given "from" to "to" block.
     * @param from block to start calculating reward
     * @param to block to finish calculating reward
     * @return the multiplier for the period
     */
    function _getMultiplier(uint256 from, uint256 to) internal view returns (uint256) {
        if (to <= endBlock) {
            return to - from;
        } else if (from >= endBlock) {
            return 0;
        } else {
            return endBlock - from;
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
        _;
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;
    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }
    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }
    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.
        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {IERC20} from '@openzeppelin/contracts/token/ERC20/IERC20.sol';
interface IMintableERC20 is IERC20 {
    function SUPPLY_CAP() external view returns (uint256);
    function mint(address account, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) 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 `amount` 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 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
    /**
     * @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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
pragma solidity ^0.8.0;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }
    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {Ownable} from '@openzeppelin/contracts/access/Ownable.sol';
import {ERC20} from '@openzeppelin/contracts/token/ERC20/ERC20.sol';
import {IMintableERC20} from './IMintableERC20.sol';
contract X2Y2Token is ERC20, Ownable, IMintableERC20 {
    uint256 private immutable _SUPPLY_CAP;
    constructor(
        address _premintReceiver,
        uint256 _premintAmount,
        uint256 _cap
    ) ERC20('X2Y2Token', 'X2Y2') {
        require(_cap > _premintAmount, 'Premint exceeds cap');
        // Transfer the sum of the premint to address
        _mint(_premintReceiver, _premintAmount);
        _SUPPLY_CAP = _cap;
    }
    function mint(address account, uint256 amount)
        external
        override
        onlyOwner
        returns (bool status)
    {
        if (totalSupply() + amount <= _SUPPLY_CAP) {
            _mint(account, amount);
            return true;
        }
        return false;
    }
    /**
     * @notice View supply cap
     */
    function SUPPLY_CAP() external view override returns (uint256) {
        return _SUPPLY_CAP;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../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.
 *
 * By default, the owner account will be the one that deploys the contract. 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;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }
    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }
    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }
    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing 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 {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _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 v4.4.1 (token/ERC20/ERC20.sol)
pragma solidity ^0.8.0;
import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";
/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    uint256 private _totalSupply;
    string private _name;
    string private _symbol;
    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }
    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }
    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }
    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }
    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }
    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }
    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }
    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }
    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }
    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }
        return true;
    }
    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
        return true;
    }
    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
        }
        return true;
    }
    /**
     * @dev Moves `amount` of tokens from `sender` to `recipient`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        _beforeTokenTransfer(sender, recipient, amount);
        uint256 senderBalance = _balances[sender];
        require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[sender] = senderBalance - amount;
        }
        _balances[recipient] += amount;
        emit Transfer(sender, recipient, amount);
        _afterTokenTransfer(sender, recipient, amount);
    }
    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");
        _beforeTokenTransfer(address(0), account, amount);
        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);
        _afterTokenTransfer(address(0), account, amount);
    }
    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");
        _beforeTokenTransfer(account, address(0), amount);
        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;
        emit Transfer(account, address(0), amount);
        _afterTokenTransfer(account, address(0), amount);
    }
    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }
    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {IERC20} from '@openzeppelin/contracts/token/ERC20/IERC20.sol';
interface IMintableERC20 is IERC20 {
    function SUPPLY_CAP() external view returns (uint256);
    function mint(address account, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
 * @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;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) 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 `amount` 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 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
    /**
     * @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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);
    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);
    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {Ownable} from '@openzeppelin/contracts/access/Ownable.sol';
import {ReentrancyGuard} from '@openzeppelin/contracts/security/ReentrancyGuard.sol';
import {IERC20, SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
/**
 * @title TokenSplitter
 * @notice It splits X2Y2 to team/treasury/trading volume reward accounts based on shares.
 */
contract TokenSplitter is Ownable, ReentrancyGuard {
    using SafeERC20 for IERC20;
    struct AccountInfo {
        uint256 shares;
        uint256 tokensDistributedToAccount;
    }
    uint256 public immutable TOTAL_SHARES;
    IERC20 public immutable x2y2Token;
    // Total tokens distributed across all accounts
    uint256 public totalTokensDistributed;
    mapping(address => AccountInfo) public accountInfo;
    event NewSharesOwner(address indexed oldRecipient, address indexed newRecipient);
    event TokensTransferred(address indexed account, uint256 amount);
    /**
     * @notice Constructor
     * @param _accounts array of accounts addresses
     * @param _shares array of shares per account
     * @param _x2y2Token address of the X2Y2 token
     */
    constructor(
        address[] memory _accounts,
        uint256[] memory _shares,
        address _x2y2Token
    ) {
        require(_accounts.length == _shares.length, 'Splitter: Length differ');
        require(_accounts.length > 0, 'Splitter: Length must be > 0');
        uint256 currentShares;
        for (uint256 i = 0; i < _accounts.length; i++) {
            require(_shares[i] > 0, 'Splitter: Shares are 0');
            currentShares += _shares[i];
            accountInfo[_accounts[i]].shares = _shares[i];
        }
        TOTAL_SHARES = currentShares;
        x2y2Token = IERC20(_x2y2Token);
    }
    /**
     * @notice Release X2Y2 tokens to the account
     * @param account address of the account
     */
    function releaseTokens(address account) external nonReentrant {
        require(accountInfo[account].shares > 0, 'Splitter: Account has no share');
        // Calculate amount to transfer to the account
        uint256 totalTokensReceived = x2y2Token.balanceOf(address(this)) + totalTokensDistributed;
        uint256 pendingRewards = ((totalTokensReceived * accountInfo[account].shares) /
            TOTAL_SHARES) - accountInfo[account].tokensDistributedToAccount;
        // Revert if equal to 0
        require(pendingRewards != 0, 'Splitter: Nothing to transfer');
        accountInfo[account].tokensDistributedToAccount += pendingRewards;
        totalTokensDistributed += pendingRewards;
        // Transfer funds to account
        x2y2Token.safeTransfer(account, pendingRewards);
        emit TokensTransferred(account, pendingRewards);
    }
    /**
     * @notice Update share recipient
     * @param _newRecipient address of the new recipient
     * @param _currentRecipient address of the current recipient
     */
    function updateSharesOwner(address _newRecipient, address _currentRecipient)
        external
        onlyOwner
    {
        require(
            accountInfo[_currentRecipient].shares > 0,
            'Owner: Current recipient has no shares'
        );
        require(accountInfo[_newRecipient].shares == 0, 'Owner: New recipient has existing shares');
        // Copy shares to new recipient
        accountInfo[_newRecipient].shares = accountInfo[_currentRecipient].shares;
        accountInfo[_newRecipient].tokensDistributedToAccount = accountInfo[_currentRecipient]
            .tokensDistributedToAccount;
        // Reset existing shares
        accountInfo[_currentRecipient].shares = 0;
        accountInfo[_currentRecipient].tokensDistributedToAccount = 0;
        emit NewSharesOwner(_currentRecipient, _newRecipient);
    }
    /**
     * @notice Retrieve amount of X2Y2 tokens that can be transferred
     * @param account address of the account
     */
    function calculatePendingRewards(address account) external view returns (uint256) {
        if (accountInfo[account].shares == 0) {
            return 0;
        }
        uint256 totalTokensReceived = x2y2Token.balanceOf(address(this)) + totalTokensDistributed;
        uint256 pendingRewards = ((totalTokensReceived * accountInfo[account].shares) /
            TOTAL_SHARES) - accountInfo[account].tokensDistributedToAccount;
        return pendingRewards;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)
pragma solidity ^0.8.0;
import "../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.
 *
 * By default, the owner account will be the one that deploys the contract. 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;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }
    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }
    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }
    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing 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 {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _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 v4.4.1 (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() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
        _;
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;
    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }
    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }
    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.
        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
 * @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;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) 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 `amount` 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 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
    /**
     * @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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
pragma solidity ^0.8.0;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }
    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {AccessControl} from '@openzeppelin/contracts/access/AccessControl.sol';
import {IERC20, SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
import {ReentrancyGuard} from '@openzeppelin/contracts/security/ReentrancyGuard.sol';
import {TokenDistributor} from './TokenDistributor.sol';
import {IStakeFor} from './IStakeFor.sol';
/**
 * @title FeeSharingSystem
 * @notice It handles the distribution of fees using
 * WETH along with the auto-compounding of X2Y2.
 */
contract FeeSharingSystem is ReentrancyGuard, AccessControl, IStakeFor {
    using SafeERC20 for IERC20;
    // for `depositFor` call
    bytes32 public constant DEPOSIT_ROLE = keccak256('DEPOSIT_ROLE');
    // for `updateRewards()`
    bytes32 public constant REWARD_UPDATE_ROLE = keccak256('REWARD_UPDATE_ROLE');
    struct UserInfo {
        uint256 shares; // shares of token staked
        uint256 userRewardPerTokenPaid; // user reward per token paid
        uint256 rewards; // pending rewards
    }
    // Precision factor for calculating rewards and exchange rate
    uint256 public constant PRECISION_FACTOR = 10**18;
    IERC20 public immutable x2y2Token;
    IERC20 public immutable rewardToken;
    TokenDistributor public immutable tokenDistributor;
    // Reward rate (block)
    uint256 public currentRewardPerBlock;
    // Last reward adjustment block number
    uint256 public lastRewardAdjustment;
    // Last update block for rewards
    uint256 public lastUpdateBlock;
    // Current end block for the current reward period
    uint256 public periodEndBlock;
    // Reward per token stored
    uint256 public rewardPerTokenStored;
    // Total existing shares
    uint256 public totalShares;
    mapping(address => UserInfo) public userInfo;
    event Deposit(address indexed user, uint256 amount, uint256 harvestedAmount);
    event Harvest(address indexed user, uint256 harvestedAmount);
    event NewRewardPeriod(uint256 numberBlocks, uint256 rewardPerBlock, uint256 reward);
    event Withdraw(address indexed user, uint256 amount, uint256 harvestedAmount);
    /**
     * @notice Constructor
     * @param _x2y2Token address of the token staked
     * @param _rewardToken address of the reward token
     * @param _tokenDistributor address of the token distributor contract
     */
    constructor(
        address _x2y2Token,
        address _rewardToken,
        address _tokenDistributor
    ) {
        rewardToken = IERC20(_rewardToken);
        x2y2Token = IERC20(_x2y2Token);
        tokenDistributor = TokenDistributor(_tokenDistributor);
        _grantRole(DEFAULT_ADMIN_ROLE, msg.sender);
    }
    /**
     * @notice deposit on behalf of `user`, must be called on fresh deposit only
     * @param user deposit user
     * @param amount amount to deposit
     */
    function depositFor(address user, uint256 amount)
        external
        override
        nonReentrant
        onlyRole(DEPOSIT_ROLE)
        returns (bool)
    {
        require(amount >= PRECISION_FACTOR, 'Deposit: Amount must be >= 1 X2Y2');
        // Auto compounds for everyone
        tokenDistributor.harvestAndCompound();
        // Update reward for user
        _updateReward(user);
        // Retrieve total amount staked by this contract
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        // transfer stakingToken from **sender**
        x2y2Token.safeTransferFrom(msg.sender, address(this), amount);
        uint256 currentShares;
        // Calculate the number of shares to issue for the user
        if (totalShares != 0) {
            currentShares = (amount * totalShares) / totalAmountStaked;
            // This is a sanity check to prevent deposit for 0 shares
            require(currentShares != 0, 'Deposit: Fail');
        } else {
            currentShares = amount;
        }
        // Adjust internal shares
        userInfo[user].shares += currentShares;
        totalShares += currentShares;
        // Verify X2Y2 token allowance and adjust if necessary
        _checkAndAdjustX2Y2TokenAllowanceIfRequired(amount, address(tokenDistributor));
        // Deposit user amount in the token distributor contract
        tokenDistributor.deposit(amount);
        emit Deposit(user, amount, 0);
        return true;
    }
    /**
     * @notice Deposit staked tokens (and collect reward tokens if requested)
     * @param amount amount to deposit (in X2Y2)
     * @param claimRewardToken whether to claim reward tokens
     * @dev There is a limit of 1 X2Y2 per deposit to prevent potential manipulation of current shares
     */
    function deposit(uint256 amount, bool claimRewardToken) external nonReentrant {
        require(amount >= PRECISION_FACTOR, 'Deposit: Amount must be >= 1 X2Y2');
        // Auto compounds for everyone
        tokenDistributor.harvestAndCompound();
        // Update reward for user
        _updateReward(msg.sender);
        // Retrieve total amount staked by this contract
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        // Transfer X2Y2 tokens to this address
        x2y2Token.safeTransferFrom(msg.sender, address(this), amount);
        uint256 currentShares;
        // Calculate the number of shares to issue for the user
        if (totalShares != 0) {
            currentShares = (amount * totalShares) / totalAmountStaked;
            // This is a sanity check to prevent deposit for 0 shares
            require(currentShares != 0, 'Deposit: Fail');
        } else {
            currentShares = amount;
        }
        // Adjust internal shares
        userInfo[msg.sender].shares += currentShares;
        totalShares += currentShares;
        uint256 pendingRewards;
        if (claimRewardToken) {
            // Fetch pending rewards
            pendingRewards = userInfo[msg.sender].rewards;
            if (pendingRewards > 0) {
                userInfo[msg.sender].rewards = 0;
                rewardToken.safeTransfer(msg.sender, pendingRewards);
            }
        }
        // Verify X2Y2 token allowance and adjust if necessary
        _checkAndAdjustX2Y2TokenAllowanceIfRequired(amount, address(tokenDistributor));
        // Deposit user amount in the token distributor contract
        tokenDistributor.deposit(amount);
        emit Deposit(msg.sender, amount, pendingRewards);
    }
    /**
     * @notice Harvest reward tokens that are pending
     */
    function harvest() external nonReentrant {
        // Auto compounds for everyone
        tokenDistributor.harvestAndCompound();
        // Update reward for user
        _updateReward(msg.sender);
        // Retrieve pending rewards
        uint256 pendingRewards = userInfo[msg.sender].rewards;
        // If pending rewards are null, revert
        require(pendingRewards > 0, 'Harvest: Pending rewards must be > 0');
        // Adjust user rewards and transfer
        userInfo[msg.sender].rewards = 0;
        // Transfer reward token to sender
        rewardToken.safeTransfer(msg.sender, pendingRewards);
        emit Harvest(msg.sender, pendingRewards);
    }
    /**
     * @notice Withdraw staked tokens (and collect reward tokens if requested)
     * @param shares shares to withdraw
     * @param claimRewardToken whether to claim reward tokens
     */
    function withdraw(uint256 shares, bool claimRewardToken) external nonReentrant {
        require(
            (shares > 0) && (shares <= userInfo[msg.sender].shares),
            'Withdraw: Shares equal to 0 or larger than user shares'
        );
        _withdraw(shares, claimRewardToken);
    }
    /**
     * @notice Withdraw all staked tokens (and collect reward tokens if requested)
     * @param claimRewardToken whether to claim reward tokens
     */
    function withdrawAll(bool claimRewardToken) external nonReentrant {
        _withdraw(userInfo[msg.sender].shares, claimRewardToken);
    }
    /**
     * @notice Update the reward per block (in rewardToken)
     * @dev Only callable by owner. Owner is meant to be another smart contract.
     */
    function updateRewards(uint256 reward, uint256 rewardDurationInBlocks)
        external
        onlyRole(REWARD_UPDATE_ROLE)
    {
        // Adjust the current reward per block
        if (block.number >= periodEndBlock) {
            currentRewardPerBlock = reward / rewardDurationInBlocks;
        } else {
            currentRewardPerBlock =
                (reward + ((periodEndBlock - block.number) * currentRewardPerBlock)) /
                rewardDurationInBlocks;
        }
        lastUpdateBlock = block.number;
        periodEndBlock = block.number + rewardDurationInBlocks;
        emit NewRewardPeriod(rewardDurationInBlocks, currentRewardPerBlock, reward);
    }
    /**
     * @notice Calculate pending rewards (WETH) for a user
     * @param user address of the user
     */
    function calculatePendingRewards(address user) external view returns (uint256) {
        return _calculatePendingRewards(user);
    }
    /**
     * @notice Calculate value of X2Y2 for a user given a number of shares owned
     * @param user address of the user
     */
    function calculateSharesValueInX2Y2(address user) external view returns (uint256) {
        // Retrieve amount staked
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        // Adjust for pending rewards
        totalAmountStaked += tokenDistributor.calculatePendingRewards(address(this));
        // Return user pro-rata of total shares
        return
            userInfo[user].shares == 0
                ? 0
                : (totalAmountStaked * userInfo[user].shares) / totalShares;
    }
    /**
     * @notice Calculate price of one share (in X2Y2 token)
     * Share price is expressed times 1e18
     */
    function calculateSharePriceInX2Y2() external view returns (uint256) {
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        // Adjust for pending rewards
        totalAmountStaked += tokenDistributor.calculatePendingRewards(address(this));
        return
            totalShares == 0
                ? PRECISION_FACTOR
                : (totalAmountStaked * PRECISION_FACTOR) / (totalShares);
    }
    /**
     * @notice Return last block where trading rewards were distributed
     */
    function lastRewardBlock() external view returns (uint256) {
        return _lastRewardBlock();
    }
    /**
     * @notice Calculate pending rewards for a user
     * @param user address of the user
     */
    function _calculatePendingRewards(address user) internal view returns (uint256) {
        return
            ((userInfo[user].shares *
                (_rewardPerToken() - (userInfo[user].userRewardPerTokenPaid))) / PRECISION_FACTOR) +
            userInfo[user].rewards;
    }
    /**
     * @notice Check current allowance and adjust if necessary
     * @param _amount amount to transfer
     * @param _to token to transfer
     */
    function _checkAndAdjustX2Y2TokenAllowanceIfRequired(uint256 _amount, address _to) internal {
        if (x2y2Token.allowance(address(this), _to) < _amount) {
            x2y2Token.approve(_to, type(uint256).max);
        }
    }
    /**
     * @notice Return last block where rewards must be distributed
     */
    function _lastRewardBlock() internal view returns (uint256) {
        return block.number < periodEndBlock ? block.number : periodEndBlock;
    }
    /**
     * @notice Return reward per token
     */
    function _rewardPerToken() internal view returns (uint256) {
        if (totalShares == 0) {
            return rewardPerTokenStored;
        }
        return
            rewardPerTokenStored +
            ((_lastRewardBlock() - lastUpdateBlock) * (currentRewardPerBlock * PRECISION_FACTOR)) /
            totalShares;
    }
    /**
     * @notice Update reward for a user account
     * @param _user address of the user
     */
    function _updateReward(address _user) internal {
        if (block.number != lastUpdateBlock) {
            rewardPerTokenStored = _rewardPerToken();
            lastUpdateBlock = _lastRewardBlock();
        }
        userInfo[_user].rewards = _calculatePendingRewards(_user);
        userInfo[_user].userRewardPerTokenPaid = rewardPerTokenStored;
    }
    /**
     * @notice Withdraw staked tokens (and collect reward tokens if requested)
     * @param shares shares to withdraw
     * @param claimRewardToken whether to claim reward tokens
     */
    function _withdraw(uint256 shares, bool claimRewardToken) internal {
        // Auto compounds for everyone
        tokenDistributor.harvestAndCompound();
        // Update reward for user
        _updateReward(msg.sender);
        // Retrieve total amount staked and calculated current amount (in X2Y2)
        (uint256 totalAmountStaked, ) = tokenDistributor.userInfo(address(this));
        uint256 currentAmount = (totalAmountStaked * shares) / totalShares;
        userInfo[msg.sender].shares -= shares;
        totalShares -= shares;
        // Withdraw amount equivalent in shares
        tokenDistributor.withdraw(currentAmount);
        uint256 pendingRewards;
        if (claimRewardToken) {
            // Fetch pending rewards
            pendingRewards = userInfo[msg.sender].rewards;
            if (pendingRewards > 0) {
                userInfo[msg.sender].rewards = 0;
                rewardToken.safeTransfer(msg.sender, pendingRewards);
            }
        }
        // Transfer X2Y2 tokens to sender
        x2y2Token.safeTransfer(msg.sender, currentAmount);
        emit Withdraw(msg.sender, currentAmount, pendingRewards);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/AccessControl.sol)
pragma solidity ^0.8.0;
import "./IAccessControl.sol";
import "../utils/Context.sol";
import "../utils/Strings.sol";
import "../utils/introspection/ERC165.sol";
/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }
    mapping(bytes32 => RoleData) private _roles;
    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;
    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role, _msgSender());
        _;
    }
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControl).interfaceId || super.supportsInterface(interfaceId);
    }
    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view override returns (bool) {
        return _roles[role].members[account];
    }
    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        Strings.toHexString(uint160(account), 20),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }
    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view override returns (bytes32) {
        return _roles[role].adminRole;
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }
    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }
    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been revoked `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual override {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");
        _revokeRole(role, account);
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     *
     * NOTE: This function is deprecated in favor of {_grantRole}.
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }
    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }
    /**
     * @dev Grants `role` to `account`.
     *
     * Internal function without access restriction.
     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }
    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)
pragma solidity ^0.8.0;
import "../IERC20.sol";
import "../../../utils/Address.sol";
/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;
    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }
    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }
    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }
    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }
    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.
        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (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() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");
        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
        _;
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {ReentrancyGuard} from '@openzeppelin/contracts/security/ReentrancyGuard.sol';
import {IERC20, SafeERC20} from '@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol';
import {IMintableERC20} from './IMintableERC20.sol';
/**
 * @title TokenDistributor
 * @notice It handles the distribution of X2Y2 token.
 * It auto-adjusts block rewards over a set number of periods.
 */
contract TokenDistributor is ReentrancyGuard {
    using SafeERC20 for IERC20;
    using SafeERC20 for IMintableERC20;
    struct StakingPeriod {
        uint256 rewardPerBlockForStaking;
        uint256 rewardPerBlockForOthers;
        uint256 periodLengthInBlock;
    }
    struct UserInfo {
        uint256 amount; // Amount of staked tokens provided by user
        uint256 rewardDebt; // Reward debt
    }
    // Precision factor for calculating rewards
    uint256 public constant PRECISION_FACTOR = 10**12;
    IMintableERC20 public immutable x2y2Token;
    address public immutable tokenSplitter;
    // Number of reward periods
    uint256 public immutable NUMBER_PERIODS;
    // Block number when rewards start
    uint256 public immutable START_BLOCK;
    // Accumulated tokens per share
    uint256 public accTokenPerShare;
    // Current phase for rewards
    uint256 public currentPhase;
    // Block number when rewards end
    uint256 public endBlock;
    // Block number of the last update
    uint256 public lastRewardBlock;
    // Tokens distributed per block for other purposes (team + treasury + trading rewards)
    uint256 public rewardPerBlockForOthers;
    // Tokens distributed per block for staking
    uint256 public rewardPerBlockForStaking;
    // Total amount staked
    uint256 public totalAmountStaked;
    mapping(uint256 => StakingPeriod) public stakingPeriod;
    mapping(address => UserInfo) public userInfo;
    event Compound(address indexed user, uint256 harvestedAmount);
    event Deposit(address indexed user, uint256 amount, uint256 harvestedAmount);
    event NewRewardsPerBlock(
        uint256 indexed currentPhase,
        uint256 startBlock,
        uint256 rewardPerBlockForStaking,
        uint256 rewardPerBlockForOthers
    );
    event Withdraw(address indexed user, uint256 amount, uint256 harvestedAmount);
    /**
     * @notice Constructor
     * @param _x2y2Token token address
     * @param _tokenSplitter token splitter contract address (for team and trading rewards)
     * @param _startBlock start block for reward program
     * @param _rewardsPerBlockForStaking array of rewards per block for staking
     * @param _rewardsPerBlockForOthers array of rewards per block for other purposes (team + treasury + trading rewards)
     * @param _periodLengthesInBlocks array of period lengthes
     * @param _numberPeriods number of periods with different rewards/lengthes (e.g., if 3 changes --> 4 periods)
     */
    constructor(
        address _x2y2Token,
        address _tokenSplitter,
        uint256 _startBlock,
        uint256[] memory _rewardsPerBlockForStaking,
        uint256[] memory _rewardsPerBlockForOthers,
        uint256[] memory _periodLengthesInBlocks,
        uint256 _numberPeriods
    ) {
        require(
            (_periodLengthesInBlocks.length == _numberPeriods) &&
                (_rewardsPerBlockForStaking.length == _numberPeriods) &&
                (_rewardsPerBlockForStaking.length == _numberPeriods),
            'Distributor: Lengthes must match numberPeriods'
        );
        // 1. Operational checks for supply
        uint256 nonCirculatingSupply = IMintableERC20(_x2y2Token).SUPPLY_CAP() -
            IMintableERC20(_x2y2Token).totalSupply();
        uint256 amountTokensToBeMinted;
        for (uint256 i = 0; i < _numberPeriods; i++) {
            amountTokensToBeMinted +=
                (_rewardsPerBlockForStaking[i] * _periodLengthesInBlocks[i]) +
                (_rewardsPerBlockForOthers[i] * _periodLengthesInBlocks[i]);
            stakingPeriod[i] = StakingPeriod({
                rewardPerBlockForStaking: _rewardsPerBlockForStaking[i],
                rewardPerBlockForOthers: _rewardsPerBlockForOthers[i],
                periodLengthInBlock: _periodLengthesInBlocks[i]
            });
        }
        require(
            amountTokensToBeMinted == nonCirculatingSupply,
            'Distributor: Wrong reward parameters'
        );
        // 2. Store values
        x2y2Token = IMintableERC20(_x2y2Token);
        tokenSplitter = _tokenSplitter;
        rewardPerBlockForStaking = _rewardsPerBlockForStaking[0];
        rewardPerBlockForOthers = _rewardsPerBlockForOthers[0];
        START_BLOCK = _startBlock;
        endBlock = _startBlock + _periodLengthesInBlocks[0];
        NUMBER_PERIODS = _numberPeriods;
        // Set the lastRewardBlock as the startBlock
        lastRewardBlock = _startBlock;
    }
    /**
     * @notice Deposit staked tokens and compounds pending rewards
     * @param amount amount to deposit (in X2Y2)
     */
    function deposit(uint256 amount) external nonReentrant {
        require(amount > 0, 'Deposit: Amount must be > 0');
        require(block.number >= START_BLOCK, 'Deposit: Not started yet');
        // Update pool information
        _updatePool();
        // Transfer X2Y2 tokens to this contract
        x2y2Token.safeTransferFrom(msg.sender, address(this), amount);
        uint256 pendingRewards;
        // If not new deposit, calculate pending rewards (for auto-compounding)
        if (userInfo[msg.sender].amount > 0) {
            pendingRewards =
                ((userInfo[msg.sender].amount * accTokenPerShare) / PRECISION_FACTOR) -
                userInfo[msg.sender].rewardDebt;
        }
        // Adjust user information
        userInfo[msg.sender].amount += (amount + pendingRewards);
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        // Increase totalAmountStaked
        totalAmountStaked += (amount + pendingRewards);
        emit Deposit(msg.sender, amount, pendingRewards);
    }
    /**
     * @notice Compound based on pending rewards
     */
    function harvestAndCompound() external nonReentrant {
        // Update pool information
        _updatePool();
        // Calculate pending rewards
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        // Return if no pending rewards
        if (pendingRewards == 0) {
            // It doesn't throw revertion (to help with the fee-sharing auto-compounding contract)
            return;
        }
        // Adjust user amount for pending rewards
        userInfo[msg.sender].amount += pendingRewards;
        // Adjust totalAmountStaked
        totalAmountStaked += pendingRewards;
        // Recalculate reward debt based on new user amount
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        emit Compound(msg.sender, pendingRewards);
    }
    /**
     * @notice Update pool rewards
     */
    function updatePool() external nonReentrant {
        _updatePool();
    }
    /**
     * @notice Withdraw staked tokens and compound pending rewards
     * @param amount amount to withdraw
     */
    function withdraw(uint256 amount) external nonReentrant {
        require(
            (userInfo[msg.sender].amount >= amount) && (amount > 0),
            'Withdraw: Amount must be > 0 or lower than user balance'
        );
        // Update pool
        _updatePool();
        // Calculate pending rewards
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        // Adjust user information
        userInfo[msg.sender].amount = userInfo[msg.sender].amount + pendingRewards - amount;
        userInfo[msg.sender].rewardDebt =
            (userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR;
        // Adjust total amount staked
        totalAmountStaked = totalAmountStaked + pendingRewards - amount;
        // Transfer X2Y2 tokens to the sender
        x2y2Token.safeTransfer(msg.sender, amount);
        emit Withdraw(msg.sender, amount, pendingRewards);
    }
    /**
     * @notice Withdraw all staked tokens and collect tokens
     */
    function withdrawAll() external nonReentrant {
        require(userInfo[msg.sender].amount > 0, 'Withdraw: Amount must be > 0');
        // Update pool
        _updatePool();
        // Calculate pending rewards and amount to transfer (to the sender)
        uint256 pendingRewards = ((userInfo[msg.sender].amount * accTokenPerShare) /
            PRECISION_FACTOR) - userInfo[msg.sender].rewardDebt;
        uint256 amountToTransfer = userInfo[msg.sender].amount + pendingRewards;
        // Adjust total amount staked
        totalAmountStaked = totalAmountStaked - userInfo[msg.sender].amount;
        // Adjust user information
        userInfo[msg.sender].amount = 0;
        userInfo[msg.sender].rewardDebt = 0;
        // Transfer X2Y2 tokens to the sender
        x2y2Token.safeTransfer(msg.sender, amountToTransfer);
        emit Withdraw(msg.sender, amountToTransfer, pendingRewards);
    }
    /**
     * @notice Calculate pending rewards for a user
     * @param user address of the user
     * @return Pending rewards
     */
    function calculatePendingRewards(address user) external view returns (uint256) {
        if ((block.number > lastRewardBlock) && (totalAmountStaked != 0)) {
            uint256 multiplier = _getMultiplier(lastRewardBlock, block.number);
            uint256 tokenRewardForStaking = multiplier * rewardPerBlockForStaking;
            uint256 adjustedEndBlock = endBlock;
            uint256 adjustedCurrentPhase = currentPhase;
            // Check whether to adjust multipliers and reward per block
            while (
                (block.number > adjustedEndBlock) && (adjustedCurrentPhase < (NUMBER_PERIODS - 1))
            ) {
                // Update current phase
                adjustedCurrentPhase++;
                // Update rewards per block
                uint256 adjustedRewardPerBlockForStaking = stakingPeriod[adjustedCurrentPhase]
                    .rewardPerBlockForStaking;
                // Calculate adjusted block number
                uint256 previousEndBlock = adjustedEndBlock;
                // Update end block
                adjustedEndBlock =
                    previousEndBlock +
                    stakingPeriod[adjustedCurrentPhase].periodLengthInBlock;
                // Calculate new multiplier
                uint256 newMultiplier = (block.number <= adjustedEndBlock)
                    ? (block.number - previousEndBlock)
                    : stakingPeriod[adjustedCurrentPhase].periodLengthInBlock;
                // Adjust token rewards for staking
                tokenRewardForStaking += (newMultiplier * adjustedRewardPerBlockForStaking);
            }
            uint256 adjustedTokenPerShare = accTokenPerShare +
                (tokenRewardForStaking * PRECISION_FACTOR) /
                totalAmountStaked;
            return
                (userInfo[user].amount * adjustedTokenPerShare) /
                PRECISION_FACTOR -
                userInfo[user].rewardDebt;
        } else {
            return
                (userInfo[user].amount * accTokenPerShare) /
                PRECISION_FACTOR -
                userInfo[user].rewardDebt;
        }
    }
    /**
     * @notice Update reward variables of the pool
     */
    function _updatePool() internal {
        if (block.number <= lastRewardBlock) {
            return;
        }
        if (totalAmountStaked == 0) {
            lastRewardBlock = block.number;
            return;
        }
        // Calculate multiplier
        uint256 multiplier = _getMultiplier(lastRewardBlock, block.number);
        // Calculate rewards for staking and others
        uint256 tokenRewardForStaking = multiplier * rewardPerBlockForStaking;
        uint256 tokenRewardForOthers = multiplier * rewardPerBlockForOthers;
        // Check whether to adjust multipliers and reward per block
        while ((block.number > endBlock) && (currentPhase < (NUMBER_PERIODS - 1))) {
            // Update rewards per block
            _updateRewardsPerBlock(endBlock);
            uint256 previousEndBlock = endBlock;
            // Adjust the end block
            endBlock += stakingPeriod[currentPhase].periodLengthInBlock;
            // Adjust multiplier to cover the missing periods with other lower inflation schedule
            uint256 newMultiplier = _getMultiplier(previousEndBlock, block.number);
            // Adjust token rewards
            tokenRewardForStaking += (newMultiplier * rewardPerBlockForStaking);
            tokenRewardForOthers += (newMultiplier * rewardPerBlockForOthers);
        }
        // Mint tokens only if token rewards for staking are not null
        if (tokenRewardForStaking > 0) {
            // It allows protection against potential issues to prevent funds from being locked
            bool mintStatus = x2y2Token.mint(address(this), tokenRewardForStaking);
            if (mintStatus) {
                accTokenPerShare =
                    accTokenPerShare +
                    ((tokenRewardForStaking * PRECISION_FACTOR) / totalAmountStaked);
            }
            x2y2Token.mint(tokenSplitter, tokenRewardForOthers);
        }
        // Update last reward block only if it wasn't updated after or at the end block
        if (lastRewardBlock <= endBlock) {
            lastRewardBlock = block.number;
        }
    }
    /**
     * @notice Update rewards per block
     * @dev Rewards are halved by 2 (for staking + others)
     */
    function _updateRewardsPerBlock(uint256 _newStartBlock) internal {
        // Update current phase
        currentPhase++;
        // Update rewards per block
        rewardPerBlockForStaking = stakingPeriod[currentPhase].rewardPerBlockForStaking;
        rewardPerBlockForOthers = stakingPeriod[currentPhase].rewardPerBlockForOthers;
        emit NewRewardsPerBlock(
            currentPhase,
            _newStartBlock,
            rewardPerBlockForStaking,
            rewardPerBlockForOthers
        );
    }
    /**
     * @notice Return reward multiplier over the given "from" to "to" block.
     * @param from block to start calculating reward
     * @param to block to finish calculating reward
     * @return the multiplier for the period
     */
    function _getMultiplier(uint256 from, uint256 to) internal view returns (uint256) {
        if (to <= endBlock) {
            return to - from;
        } else if (from >= endBlock) {
            return 0;
        } else {
            return endBlock - from;
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
interface IStakeFor {
    function depositFor(address user, uint256 amount) external returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)
pragma solidity ^0.8.0;
/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControl {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);
    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);
    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);
    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);
    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;
    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;
    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
pragma solidity ^0.8.0;
/**
 * @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;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)
pragma solidity ^0.8.0;
/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";
    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol
        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }
    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)
pragma solidity ^0.8.0;
import "./IERC165.sol";
/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)
pragma solidity ^0.8.0;
/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);
    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);
    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) 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 `amount` 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 amount) external returns (bool);
    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);
    /**
     * @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);
}
// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)
pragma solidity ^0.8.0;
/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }
    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");
        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }
    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }
    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }
    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import {IERC20} from '@openzeppelin/contracts/token/ERC20/IERC20.sol';
interface IMintableERC20 is IERC20 {
    function SUPPLY_CAP() external view returns (uint256);
    function mint(address account, uint256 amount) external returns (bool);
}

// Copyright (C) 2015, 2016, 2017 Dapphub

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.4.18;

contract WETH9 {
    string public name     = "Wrapped Ether";
    string public symbol   = "WETH";
    uint8  public decimals = 18;

    event  Approval(address indexed src, address indexed guy, uint wad);
    event  Transfer(address indexed src, address indexed dst, uint wad);
    event  Deposit(address indexed dst, uint wad);
    event  Withdrawal(address indexed src, uint wad);

    mapping (address => uint)                       public  balanceOf;
    mapping (address => mapping (address => uint))  public  allowance;

    function() public payable {
        deposit();
    }
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        Deposit(msg.sender, msg.value);
    }
    function withdraw(uint wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint) {
        return this.balance;
    }

    function approve(address guy, uint wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(address src, address dst, uint wad)
        public
        returns (bool)
    {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        Transfer(src, dst, wad);

        return true;
    }
}


/*
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007

 Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
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APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

  16. Limitation of Liability.

  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

  17. Interpretation of Sections 15 and 16.

  If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.

                     END OF TERMS AND CONDITIONS

            How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) <year>  <name of author>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

Also add information on how to contact you by electronic and paper mail.

  If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:

    <program>  Copyright (C) <year>  <name of author>
    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".

  You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.

  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.

*/