// File: @openzeppelin\contracts\token\ERC20\IERC20.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @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: node_modules\@openzeppelin\contracts\math\SafeMath.sol


pragma solidity ^0.6.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: node_modules\@openzeppelin\contracts\utils\Address.sol


pragma solidity ^0.6.2;

/**
 * @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 in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        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");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (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");
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        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

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin\contracts\token\ERC20\SafeERC20.sol


pragma solidity ^0.6.0;




/**
 * @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 SafeMath for uint256;
    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'
        // solhint-disable-next-line max-line-length
        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).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _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
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}



// File: contracts\interfaces\nerv\IController.sol

pragma solidity 0.6.12;

interface IController {
    function withdraw(address, uint256) external;

    function balanceOf(address) external view returns (uint256);

    function earn(address, uint256) external;

    function want(address) external view returns (address);

    function rewards() external view returns (address);

    function vaults(address) external view returns (address);

    function strategies(address) external view returns (address);

    function approvedStrategies(address, address) external view returns (bool);
}

// File: contracts\interfaces\curve\Curve.sol


pragma solidity 0.6.12;

interface ICurveFi {
    function get_virtual_price() external view returns (uint256);

    function balances(uint256) external view returns (uint256);

    function add_liquidity(uint256[3] calldata amounts, uint256 min_mint_amount)
        external;

    function remove_liquidity(uint256 _amount, uint256[3] calldata amounts)
        external;

    function remove_liquidity_one_coin(
        uint256 _token_amount,
        int128 i,
        uint256 min_amount
    ) external;

    function remove_liquidity_imbalance(
        uint256[3] calldata amounts,
        uint256 max_burn_amount
    ) external;

    function exchange(
        int128 from,
        int128 to,
        uint256 _from_amount,
        uint256 _min_to_amount
    ) external;
}

// File: contracts\strategies\StrategyUSDT3pool.sol


pragma solidity 0.6.12;







interface yvERC20 {
    function deposit(uint256) external;

    function withdraw(uint256) external;

    function earn() external;

    function getPricePerFullShare() external view returns (uint256);
}

/*
 A strategy must implement the following calls;
 
 - deposit()
 - withdraw(address) must exclude any tokens used in the yield - Controller role - withdraw should return to Controller
 - withdraw(uint) - Controller | Vault role - withdraw should always return to vault
 - withdrawAll() - Controller | Vault role - withdraw should always return to vault
 - balanceOf()
 
 Where possible, strategies must remain as immutable as possible, instead of updating variables, we update the contract by linking it in the controller
 
*/

contract StrategyUSDT3pool {
    using SafeERC20 for IERC20;
    using Address for address;
    using SafeMath for uint256;

    // usdt
    address public constant want = address(
        0xdAC17F958D2ee523a2206206994597C13D831ec7
    );
    address public constant _3pool = address(
        0xbEbc44782C7dB0a1A60Cb6fe97d0b483032FF1C7
    );
    address public constant _3crv = address(
        0x6c3F90f043a72FA612cbac8115EE7e52BDe6E490
    );
    address public constant y3crv = address(
        0x9cA85572E6A3EbF24dEDd195623F188735A5179f
    );

    address public governance;
    address public controller;
    address public strategist;

    uint256 public constant DENOMINATOR = 10000;
    uint256 public treasuryFee = 500;
    uint256 public withdrawalFee = 0;
    uint256 public strategistReward = 50;
    uint256 public threshold = 6000;
    uint256 public slip = 100;
    uint256 public tank = 0;
    uint256 public p = 0;

    event Threshold(address indexed strategy);

    modifier isAuthorized() {
        require(
            msg.sender == governance ||
                msg.sender == strategist ||
                msg.sender == controller ||
                msg.sender == address(this),
            "!authorized"
        );
        _;
    }

    constructor(address _controller) public {
        governance = msg.sender;
        strategist = msg.sender;
        controller = _controller;
    }

    function getName() external pure returns (string memory) {
        return "StrategyUSDT3pool";
    }

    function deposit() public isAuthorized {
        rebalance();
        uint256 _want = (IERC20(want).balanceOf(address(this))).sub(tank);
        if (_want > 0) {
            IERC20(want).safeApprove(_3pool, 0);
            IERC20(want).safeApprove(_3pool, _want);
            uint256 v = _want.mul(1e30).div(
                ICurveFi(_3pool).get_virtual_price()
            );
            ICurveFi(_3pool).add_liquidity(
                [0, 0, _want],
                v.mul(DENOMINATOR.sub(slip)).div(DENOMINATOR)
            );
        }
        uint256 _bal = IERC20(_3crv).balanceOf(address(this));
        if (_bal > 0) {
            IERC20(_3crv).safeApprove(y3crv, 0);
            IERC20(_3crv).safeApprove(y3crv, _bal);
            yvERC20(y3crv).deposit(_bal);
        }
    }

    // Controller only function for creating additional rewards from dust
    function withdraw(IERC20 _asset) external returns (uint256 balance) {
        require(msg.sender == controller, "!controller");
        require(want != address(_asset), "want");
        require(_3crv != address(_asset), "3crv");
        require(y3crv != address(_asset), "y3crv");
        balance = _asset.balanceOf(address(this));
        _asset.safeTransfer(controller, balance);
    }

    // Withdraw partial funds, normally used with a vault withdrawal
    function withdraw(uint256 _amount) external {
        require(msg.sender == controller, "!controller");

        rebalance();
        uint256 _balance = IERC20(want).balanceOf(address(this));
        if (_balance < _amount) {
            _amount = _withdrawSome(_amount.sub(_balance));
            _amount = _amount.add(_balance);
            tank = 0;
        } else {
            if (tank >= _amount) tank = tank.sub(_amount);
            else tank = 0;
        }

        address _vault = IController(controller).vaults(address(want));
        require(_vault != address(0), "!vault"); // additional protection so we don't burn the funds
        uint256 _fee = _amount.mul(withdrawalFee).div(DENOMINATOR);
        IERC20(want).safeTransfer(IController(controller).rewards(), _fee);
        IERC20(want).safeTransfer(_vault, _amount.sub(_fee));
    }

    function _withdrawSome(uint256 _amount) internal returns (uint256) {
        uint256 _amnt = _amount.mul(1e30).div(
            ICurveFi(_3pool).get_virtual_price()
        );
        uint256 _amt = _amnt.mul(1e18).div(
            yvERC20(y3crv).getPricePerFullShare()
        );
        uint256 _before = IERC20(_3crv).balanceOf(address(this));
        yvERC20(y3crv).withdraw(_amt);
        uint256 _after = IERC20(_3crv).balanceOf(address(this));
        return _withdrawOne(_after.sub(_before));
    }

    function _withdrawOne(uint256 _amnt) internal returns (uint256) {
        uint256 _before = IERC20(want).balanceOf(address(this));
        IERC20(_3crv).safeApprove(_3pool, 0);
        IERC20(_3crv).safeApprove(_3pool, _amnt);
        ICurveFi(_3pool).remove_liquidity_one_coin(
            _amnt,
            2,
            _amnt.mul(DENOMINATOR.sub(slip)).div(DENOMINATOR).div(1e12)
        );
        uint256 _after = IERC20(want).balanceOf(address(this));

        return _after.sub(_before);
    }

    // Withdraw all funds, normally used when migrating strategies
    function withdrawAll() external returns (uint256 balance) {
        require(msg.sender == controller, "!controller");
        _withdrawAll();

        balance = IERC20(want).balanceOf(address(this));

        address _vault = IController(controller).vaults(address(want));
        require(_vault != address(0), "!vault"); // additional protection so we don't burn the funds
        IERC20(want).safeTransfer(_vault, balance);
    }

    function _withdrawAll() internal {
        uint256 _y3crv = IERC20(y3crv).balanceOf(address(this));
        if (_y3crv > 0) {
            yvERC20(y3crv).withdraw(_y3crv);
            _withdrawOne(IERC20(_3crv).balanceOf(address(this)));
        }
    }

    function balanceOfWant() public view returns (uint256) {
        return IERC20(want).balanceOf(address(this));
    }

    function balanceOf3CRV() public view returns (uint256) {
        return IERC20(_3crv).balanceOf(address(this));
    }

    function balanceOf3CRVinWant() public view returns (uint256) {
        return
            balanceOf3CRV().mul(ICurveFi(_3pool).get_virtual_price()).div(1e30);
    }

    function balanceOfy3CRV() public view returns (uint256) {
        return IERC20(y3crv).balanceOf(address(this));
    }

    function balanceOfy3CRVin3CRV() public view returns (uint256) {
        return
            balanceOfy3CRV().mul(yvERC20(y3crv).getPricePerFullShare()).div(
                1e18
            );
    }

    function balanceOfy3CRVinWant() public view returns (uint256) {
        return
            balanceOfy3CRVin3CRV()
                .mul(ICurveFi(_3pool).get_virtual_price())
                .div(1e30);
    }

    function balanceOf() public view returns (uint256) {
        return balanceOfWant().add(balanceOfy3CRVinWant());
    }


    function forceD(uint256 _amount) external isAuthorized {
        IERC20(want).safeApprove(_3pool, 0);
        IERC20(want).safeApprove(_3pool, _amount);
        uint256 v = _amount.mul(1e30).div(ICurveFi(_3pool).get_virtual_price());
        ICurveFi(_3pool).add_liquidity(
            [0, 0, _amount],
            v.mul(DENOMINATOR.sub(slip)).div(DENOMINATOR)
        );
        if (_amount < tank) tank = tank.sub(_amount);
        else tank = 0;

        uint256 _bal = IERC20(_3crv).balanceOf(address(this));
        IERC20(_3crv).safeApprove(y3crv, 0);
        IERC20(_3crv).safeApprove(y3crv, _bal);
        yvERC20(y3crv).deposit(_bal);
    }

    function forceW(uint256 _amt) external isAuthorized {
        uint256 _before = IERC20(_3crv).balanceOf(address(this));
        yvERC20(y3crv).withdraw(_amt);
        uint256 _after = IERC20(_3crv).balanceOf(address(this));
        _amt = _after.sub(_before);

        IERC20(_3crv).safeApprove(_3pool, 0);
        IERC20(_3crv).safeApprove(_3pool, _amt);
        _before = IERC20(want).balanceOf(address(this));
        ICurveFi(_3pool).remove_liquidity_one_coin(
            _amt,
            2,
            _amt.mul(DENOMINATOR.sub(slip)).div(DENOMINATOR).div(1e12)
        );
        _after = IERC20(want).balanceOf(address(this));
        tank = tank.add(_after.sub(_before));
    }

    function drip() public isAuthorized {
        uint256 _p = yvERC20(y3crv).getPricePerFullShare();
        _p = _p.mul(ICurveFi(_3pool).get_virtual_price()).div(1e18);
        require(_p >= p, "backward");
        uint256 _r = (_p.sub(p)).mul(balanceOfy3CRV()).div(1e18);
        uint256 _s = _r.mul(strategistReward).div(DENOMINATOR);
        IERC20(y3crv).safeTransfer(strategist, _s.mul(1e18).div(_p));
        uint256 _t = _r.mul(treasuryFee).div(DENOMINATOR);
        IERC20(y3crv).safeTransfer(
            IController(controller).rewards(),
            _t.mul(1e18).div(_p)
        );
        p = _p;
    }

    function tick() public view returns (uint256 _t, uint256 _c) {
        _t = ICurveFi(_3pool).balances(2).mul(threshold).div(DENOMINATOR);
        _c = balanceOfy3CRVinWant();
    }

    function rebalance() public isAuthorized {
        drip();
        (uint256 _t, uint256 _c) = tick();
        if (_c > _t) {
            _withdrawSome(_c.sub(_t));
            tank = IERC20(want).balanceOf(address(this));
            emit Threshold(address(this));
        }
    }

    function setGovernance(address _governance) external {
        require(msg.sender == governance, "!governance");
        governance = _governance;
    }

    
    function setStrategist(address _strategist) external {
        require(msg.sender == governance || msg.sender == strategist, "!gs");
        strategist = _strategist;
    }

    function setWithdrawalFee(uint256 _withdrawalFee) external {
        require(msg.sender == governance, "!governance");
        withdrawalFee = _withdrawalFee;
    }

    function setTreasuryFee(uint256 _treasuryFee) external {
        require(msg.sender == governance, "!governance");
        treasuryFee = _treasuryFee;
    }

    function setStrategistReward(uint256 _strategistReward) external {
        require(msg.sender == governance, "!governance");
        strategistReward = _strategistReward;
    }

    function setThreshold(uint256 _threshold) external {
        require(msg.sender == strategist || msg.sender == governance, "!sg");
        threshold = _threshold;
    }

    function setSlip(uint256 _slip) external {
        require(msg.sender == strategist || msg.sender == governance, "!sg");
        slip = _slip;
    }
}