// File: @openzeppelin/contracts-0.8/access/Ownable.sol



// 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);
    }
}

// File: @openzeppelin/contracts-0.8/token/ERC20/IERC20.sol



// 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);
}

// File: @openzeppelin/contracts-0.8/token/ERC20/utils/SafeERC20.sol



// 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");
        }
    }
}

// File: @openzeppelin/contracts-0.8/utils/Address.sol



// 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);
            }
        }
    }
}

// File: @openzeppelin/contracts-0.8/utils/Context.sol



// 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 {
    /**
     * @notice This function returns the address of the sender of the message.
     * @dev This function is an internal view function that returns the address of the sender of the message.
     */
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    /**
     * @notice _msgData() is an internal view function that returns the calldata of the message.
     * @dev This function is used to access the calldata of the message.
     */
    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: contracts/interfaces/IBooster.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

interface IBooster {
    struct FeeDistro {
        address distro;
        address rewards;
        bool active;
    }

    function feeTokens(address _token) external returns (FeeDistro memory);

    function earmarkFees(address _feeToken) external returns (bool);

    struct PoolInfo {
        address lptoken;
        address token;
        address gauge;
        address crvRewards;
        address stash;
        bool shutdown;
    }

    function earmarkRewards(uint256 _pid) external returns (bool);

    function poolLength() external view returns (uint256);

    function lockRewards() external view returns (address);

    function poolInfo(uint256 _pid) external view returns (PoolInfo memory poolInfo);

    function distributeL2Fees(uint256 _amount) external;

    function lockIncentive() external view returns (uint256);

    function stakerIncentive() external view returns (uint256);

    function earmarkIncentive() external view returns (uint256);

    function platformFee() external view returns (uint256);

    function FEE_DENOMINATOR() external view returns (uint256);
}

// File: contracts/interfaces/IDarkQuestBoard.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

/** @title Warden Dark Quest Board  */
/// @author Paladin
/*
    Version of Warden Quest Board allowing to blacklist veToken voters
    And not account their Bias for rewards distribution
*/
interface IDarkQuestBoard {
    // Main functions
    function createQuest(
        address gauge,
        address rewardToken,
        uint48 duration,
        uint256 objective,
        uint256 rewardPerVote,
        uint256 totalRewardAmount,
        uint256 feeAmount,
        address[] calldata blacklist
    ) external returns (uint256);

    function withdrawUnusedRewards(uint256 questID, address recipient) external;

    // Manage quest functions
    function increaseQuestDuration(
        uint256 questID,
        uint48 addedDuration,
        uint256 addedRewardAmount,
        uint256 feeAmount
    ) external;

    function increaseQuestReward(
        uint256 questID,
        uint256 newRewardPerVote,
        uint256 addedRewardAmount,
        uint256 feeAmount
    ) external;

    function increaseQuestObjective(
        uint256 questID,
        uint256 newObjective,
        uint256 addedRewardAmount,
        uint256 feeAmount
    ) external;

    function emergencyWithdraw(uint256 questID, address recipient) external;

    function addToBlacklist(uint256 questID, address account) external;

    function addMultipleToBlacklist(uint256 questID, address[] calldata accounts) external;

    function removeFromBlacklist(uint256 questID, address account) external;

    function closeQuestPeriod(uint256 period) external returns (uint256 closed, uint256 skipped);

    function quests(uint256 questID)
        external
        returns (
            address creator,
            address rewardToken,
            address gauge,
            uint48 duration,
            uint48 periodStart,
            uint256 totalRewardAmount
        );

    function questBlacklist(uint256 questID, uint256 idx) external view returns (address);

    event RemoveVoterBlacklist(uint256 indexed questID, address indexed account);
}

// File: contracts/peripheral/KeeperRole.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;
import "@openzeppelin/contracts-0.8/access/Ownable.sol";

/**
 *  @title KeeperRole
 *  @notice Keeper role to allow an address to call functions.
 *  @author Aura Finance
 */
contract KeeperRole is Ownable {
    mapping(address => bool) public authorizedKeepers;

    constructor(address _owner) {
        _transferOwnership(_owner);
    }

    /// @notice Adds or remove an address from the keeper's whitelist
    /// @param _keeper address of the authorized keeper
    /// @param _authorized Whether to add or remove keeper
    function updateAuthorizedKeepers(address _keeper, bool _authorized) external onlyOwner {
        authorizedKeepers[_keeper] = _authorized;
    }

    /* -------------------------------------------------------------------
       Modifiers 
    ------------------------------------------------------------------- */

    modifier onlyKeeper() {
        require(authorizedKeepers[msg.sender], "!keeper");
        _;
    }
}

// File: contracts/peripheral/WardenQuestScheduler.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

import { AuraMath } from "../utils/AuraMath.sol";
import { IERC20 } from "@openzeppelin/contracts-0.8/token/ERC20/IERC20.sol";
import { SafeERC20 } from "@openzeppelin/contracts-0.8/token/ERC20/utils/SafeERC20.sol";
import { KeeperRole } from "./KeeperRole.sol";
import { IDarkQuestBoard } from "../interfaces/IDarkQuestBoard.sol";
import { IBooster } from "../interfaces/IBooster.sol";

/**
 * @title   WardenQuestScheduler
 * @author  AuraFinance
 * @notice   Creates wards Quests  and withdraws incentives from Closed Quests.
 * @dev  The complete flow from quest to stash takes 4 epochs:
 *
 *  1.- Anyone at epoch N creates a quest with duration of 2 epochs.
 *  2.- Keeper at epoch N+3 withdraws undistributed rewards and queues them for epochs (N+3, N+4).
 *  3.- Keeper at epoch N+3 forwards queued rewards for a given pid.
 *  4.- Keeper at epoch N+4 forwards queued rewards for a given pid.
 */
contract WardenQuestScheduler is KeeperRole {
    using AuraMath for uint256;
    using SafeERC20 for IERC20;

    /** @notice Duration of each epoch  */
    uint256 public constant epochDuration = 7 days;
    /** @notice Total number of epochs for the Quest  */
    uint48 public constant duration = 2;
    /** @notice Address of booster */
    address public immutable booster;
    /** @notice Address of the ERC20 used for rewards  */
    address public immutable cvx;
    /** @notice Address  Ward Dark Quest Board */
    address public immutable darkQuestBoard;

    /** @notice List of Quest questId => pid */
    mapping(uint256 => uint256) public quests;

    /** @notice List of queued rewards (epoch => pid => amount) */
    mapping(uint256 => mapping(uint256 => uint256)) public rewardsQueue;

    /** @notice Event emitted when rewards are queued  */
    event QueuedRewards(uint256 epoch, uint256 pid, uint256 rewardAmount);
    /** @notice Event emitted when rewards are queued  */
    event ForwardedRewards(uint256 epoch, uint256 pid, uint256 rewardAmount);
    /** @notice Event emitted when rewards are canceled  */
    event CanceledRewards(uint256 epoch, uint256 pid, uint256 rewardAmount);

    /**
     * @param _booster Address of the booster
     * @param _cvx  Cvx token contract
     * @param _darkQuestBoard  Dark Quest Board
     * @param _owner  Multisig address , the owner of the contract.
     */
    constructor(
        address _booster,
        address _cvx,
        address _darkQuestBoard,
        address _owner
    ) KeeperRole(_owner) {
        booster = _booster;
        cvx = _cvx;
        darkQuestBoard = _darkQuestBoard;
    }

    /**
     * @notice Creates a new Quest at a predefined duration (2 epochs).
     * @dev Creates a new Quest struct, and QuestPeriods for the Quest duration
     * @param objective Target bias to reach (equivalent to amount of veCRV in wei to reach)
     * @param rewardPerVote Amount of reward per veCRV (in wei)
     * @param totalRewardAmount Total amount of rewards for the whole Quest (in wei)
     * @param feeAmount Paladin platform fees amount (in wei)
     * @return questID : ID of the newly created Quest
     */
    function createQuest(
        uint256 pid,
        uint256 objective,
        uint256 rewardPerVote,
        uint256 totalRewardAmount,
        uint256 feeAmount,
        address[] calldata blacklist
    ) external returns (uint256 questID) {
        IBooster.PoolInfo memory poolInfo = IBooster(booster).poolInfo(pid);
        require(!poolInfo.shutdown, "!shutdown");
        require(poolInfo.stash != address(0), "!stash");
        // Pull all the rewards + fee in this contract
        uint256 totalAmount = totalRewardAmount.add(feeAmount);
        IERC20(cvx).safeTransferFrom(msg.sender, address(this), totalAmount);
        IERC20(cvx).safeIncreaseAllowance(address(darkQuestBoard), totalAmount);

        questID = IDarkQuestBoard(darkQuestBoard).createQuest(
            poolInfo.gauge,
            cvx,
            duration,
            objective,
            rewardPerVote,
            totalRewardAmount,
            feeAmount,
            blacklist
        );
        quests[questID] = pid;
    }

    /**
     * @notice Withdraw all undistributed rewards from Closed Quest Periods and queues them to it's linked pid.
     * @param questID ID of the Quest
     */
    function withdrawAndQueueUnusedRewards(uint256 questID) external onlyKeeper returns (uint256 amount) {
        uint256 pid = quests[questID];
        IBooster.PoolInfo memory poolInfo = IBooster(booster).poolInfo(quests[questID]);
        require(poolInfo.stash != address(0), "!questID");

        // Validate all periods ended.
        (, , , , uint48 periodStart, ) = IDarkQuestBoard(darkQuestBoard).quests(questID);
        uint256 periodFinish = periodStart + (epochDuration * duration);

        require(block.timestamp > periodFinish, "!periodFinish");

        uint256 balanceBefore = IERC20(cvx).balanceOf(address(this));
        IDarkQuestBoard(darkQuestBoard).withdrawUnusedRewards(questID, address(this));
        uint256 balanceAfter = IERC20(cvx).balanceOf(address(this));
        amount = balanceAfter.sub(balanceBefore);
        require(amount > 0, "!amount");

        _queueRewards(pid, duration, amount);
    }

    /**
     * @notice Emergency withdraws all undistributed rewards from Closed Quest Periods & all rewards for Active Periods
     * @param questID ID of the Quest
     */
    function emergencyWithdraw(uint256 questID) external onlyOwner {
        IDarkQuestBoard(darkQuestBoard).emergencyWithdraw(questID, owner());
    }

    /**
     * @notice allow arbitrary calls to any contract to allow to manage the created quest.
     * @param _to Target address
     * @param _value Value of the call
     * @param _data call data
     */
    function execute(
        address _to,
        uint256 _value,
        bytes memory _data
    ) external onlyOwner returns (bool, bytes memory) {
        (bool success, bytes memory result) = _to.call{ value: _value }(_data);
        require(success, "!success");

        return (success, result);
    }

    /**
     * @dev Forward rewards available at current epoch
     * @param _pid the pool id
     */
    function forwardRewards(uint256 _pid) external onlyKeeper {
        _forwardRewards(_getCurrentEpoch(), _pid);
    }

    /**
     * @dev Forward rewards available
     * @param _epoch the epoch in which the rewards were queded
     * @param _pid the pool id
     */
    function forwardQueuedRewards(uint256 _epoch, uint256 _pid) external onlyKeeper {
        _forwardRewards(_epoch, _pid);
    }

    /**
     * @dev Cancels a queued reward an retrieve the queued amount.
     * @param _epoch the epoch in which the rewards were queded
     * @param _pid the pool id
     */
    function cancelQueuedRewards(uint256 _epoch, uint256 _pid) external onlyOwner {
        uint256 amount = rewardsQueue[_epoch][_pid];
        require(amount > 0, "!amount");
        rewardsQueue[_epoch][_pid] = 0;

        IERC20(cvx).safeTransfer(owner(), amount);
        emit CanceledRewards(_epoch, _pid, amount);
    }

    /**
     * @dev Get current epoch
     */
    function getCurrentEpoch() external view returns (uint256) {
        return _getCurrentEpoch();
    }

    function _getCurrentEpoch() internal view returns (uint256) {
        return block.timestamp.div(epochDuration);
    }

    /**
     * @dev Queue rewards to a pid, it splits the rewards evenly by the number of epochs provided.
     * It reverts if an epoch already has some queued rewards.
     * @param _pid the pool id
     * @param _nEpochs Number of epochs to split the rewards
     * @param _amount Amount of rewards.
     */
    function _queueRewards(
        uint256 _pid,
        uint256 _nEpochs,
        uint256 _amount
    ) internal {
        uint256 rewardAmount = _amount.div(_nEpochs);
        uint256 epoch = _getCurrentEpoch();
        for (uint256 i = 0; i < _nEpochs; i++) {
            rewardsQueue[epoch][_pid] += rewardAmount;
            emit QueuedRewards(epoch, _pid, rewardAmount);
            epoch++;
        }
    }

    function _forwardRewards(uint256 _epoch, uint256 _pid) internal {
        require(_epoch <= _getCurrentEpoch(), "!epoch");
        uint256 amount = rewardsQueue[_epoch][_pid];
        require(amount > 0, "!amount");
        rewardsQueue[_epoch][_pid] = 0;
        IBooster.PoolInfo memory poolInfo = IBooster(booster).poolInfo(_pid);

        require(!poolInfo.shutdown, "!shutdown");
        IERC20(cvx).safeTransfer(poolInfo.stash, amount);
        emit ForwardedRewards(_epoch, _pid, amount);
    }
}

// File: contracts/utils/AuraMath.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.8.11;

/// @notice A library for performing overflow-/underflow-safe math,
/// updated with awesomeness from of DappHub (https://github.com/dapphub/ds-math).
library AuraMath {
    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    function add(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a + b;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a - b;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256 c) {
        c = a * b;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute.
        return (a / 2) + (b / 2) + (((a % 2) + (b % 2)) / 2);
    }

    function to224(uint256 a) internal pure returns (uint224 c) {
        require(a <= type(uint224).max, "AuraMath: uint224 Overflow");
        c = uint224(a);
    }

    function to128(uint256 a) internal pure returns (uint128 c) {
        require(a <= type(uint128).max, "AuraMath: uint128 Overflow");
        c = uint128(a);
    }

    function to112(uint256 a) internal pure returns (uint112 c) {
        require(a <= type(uint112).max, "AuraMath: uint112 Overflow");
        c = uint112(a);
    }

    function to96(uint256 a) internal pure returns (uint96 c) {
        require(a <= type(uint96).max, "AuraMath: uint96 Overflow");
        c = uint96(a);
    }

    function to32(uint256 a) internal pure returns (uint32 c) {
        require(a <= type(uint32).max, "AuraMath: uint32 Overflow");
        c = uint32(a);
    }
}

/// @notice A library for performing overflow-/underflow-safe addition and subtraction on uint32.
library AuraMath32 {
    function sub(uint32 a, uint32 b) internal pure returns (uint32 c) {
        c = a - b;
    }
}

/// @notice A library for performing overflow-/underflow-safe addition and subtraction on uint112.
library AuraMath112 {
    function add(uint112 a, uint112 b) internal pure returns (uint112 c) {
        c = a + b;
    }

    function sub(uint112 a, uint112 b) internal pure returns (uint112 c) {
        c = a - b;
    }
}

/// @notice A library for performing overflow-/underflow-safe addition and subtraction on uint224.
library AuraMath224 {
    function add(uint224 a, uint224 b) internal pure returns (uint224 c) {
        c = a + b;
    }
}