organized_contracts/06/0611ec21c2a6112f8805ab0f5aedc8aa86564f5091498f34ab111bc99b72ec7b/main.sol

// This contract is part of Zellic’s smart contract dataset, which is a collection of publicly available contract code gathered as of March 2023.

// SPDX-License-Identifier: AGPL-3.0

pragma solidity 0.6.12;
pragma experimental ABIEncoderV2;

// File: Address.sol

/**

 * @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) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**

     * @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: IERC20.sol

/**

 * @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: Math.sol

/**

 * @dev Standard math utilities missing in the Solidity language.

 */
library Math {
    /**

     * @dev Returns the largest of two numbers.

     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**

     * @dev Returns the smallest of two numbers.

     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? 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);
    }
}

// File: SafeMath.sol

/**

 * @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: uniswap.sol

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);
}

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;
}

// File: SafeERC20.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 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: BaseStrategy.sol

struct StrategyParams {
    uint256 performanceFee;
    uint256 activation;
    uint256 debtRatio;
    uint256 minDebtPerHarvest;
    uint256 maxDebtPerHarvest;
    uint256 lastReport;
    uint256 totalDebt;
    uint256 totalGain;
    uint256 totalLoss;
}

interface VaultAPI is IERC20 {
    function name() external view returns (string calldata);

    function symbol() external view returns (string calldata);

    function decimals() external view returns (uint256);

    function apiVersion() external pure returns (string memory);

    function permit(

        address owner,

        address spender,

        uint256 amount,

        uint256 expiry,

        bytes calldata signature

    ) external returns (bool);

    // NOTE: Vyper produces multiple signatures for a given function with "default" args
    function deposit() external returns (uint256);

    function deposit(uint256 amount) external returns (uint256);

    function deposit(uint256 amount, address recipient) external returns (uint256);

    // NOTE: Vyper produces multiple signatures for a given function with "default" args
    function withdraw() external returns (uint256);

    function withdraw(uint256 maxShares) external returns (uint256);

    function withdraw(uint256 maxShares, address recipient) external returns (uint256);

    function token() external view returns (address);

    function strategies(address _strategy) external view returns (StrategyParams memory);

    function pricePerShare() external view returns (uint256);

    function totalAssets() external view returns (uint256);

    function depositLimit() external view returns (uint256);

    function maxAvailableShares() external view returns (uint256);

    /**

     * View how much the Vault would increase this Strategy's borrow limit,

     * based on its present performance (since its last report). Can be used to

     * determine expectedReturn in your Strategy.

     */
    function creditAvailable() external view returns (uint256);

    /**

     * View how much the Vault would like to pull back from the Strategy,

     * based on its present performance (since its last report). Can be used to

     * determine expectedReturn in your Strategy.

     */
    function debtOutstanding() external view returns (uint256);

    /**

     * View how much the Vault expect this Strategy to return at the current

     * block, based on its present performance (since its last report). Can be

     * used to determine expectedReturn in your Strategy.

     */
    function expectedReturn() external view returns (uint256);

    /**

     * This is the main contact point where the Strategy interacts with the

     * Vault. It is critical that this call is handled as intended by the

     * Strategy. Therefore, this function will be called by BaseStrategy to

     * make sure the integration is correct.

     */
    function report(

        uint256 _gain,

        uint256 _loss,

        uint256 _debtPayment

    ) external returns (uint256);

    /**

     * This function should only be used in the scenario where the Strategy is

     * being retired but no migration of the positions are possible, or in the

     * extreme scenario that the Strategy needs to be put into "Emergency Exit"

     * mode in order for it to exit as quickly as possible. The latter scenario

     * could be for any reason that is considered "critical" that the Strategy

     * exits its position as fast as possible, such as a sudden change in

     * market conditions leading to losses, or an imminent failure in an

     * external dependency.

     */
    function revokeStrategy() external;

    /**

     * View the governance address of the Vault to assert privileged functions

     * can only be called by governance. The Strategy serves the Vault, so it

     * is subject to governance defined by the Vault.

     */
    function governance() external view returns (address);

    /**

     * View the management address of the Vault to assert privileged functions

     * can only be called by management. The Strategy serves the Vault, so it

     * is subject to management defined by the Vault.

     */
    function management() external view returns (address);

    /**

     * View the guardian address of the Vault to assert privileged functions

     * can only be called by guardian. The Strategy serves the Vault, so it

     * is subject to guardian defined by the Vault.

     */
    function guardian() external view returns (address);
}

/**

 * This interface is here for the keeper bot to use.

 */
interface StrategyAPI {
    function name() external view returns (string memory);

    function vault() external view returns (address);

    function want() external view returns (address);

    function apiVersion() external pure returns (string memory);

    function keeper() external view returns (address);

    function isActive() external view returns (bool);

    function delegatedAssets() external view returns (uint256);

    function estimatedTotalAssets() external view returns (uint256);

    function tendTrigger(uint256 callCost) external view returns (bool);

    function tend() external;

    function harvestTrigger(uint256 callCost) external view returns (bool);

    function harvest() external;

    event Harvested(uint256 profit, uint256 loss, uint256 debtPayment, uint256 debtOutstanding);
}

interface HealthCheck {
    function check(

        uint256 profit,

        uint256 loss,

        uint256 debtPayment,

        uint256 debtOutstanding,

        uint256 totalDebt

    ) external view returns (bool);
}

/**

 * @title Yearn Base Strategy

 * @author yearn.finance

 * @notice

 *  BaseStrategy implements all of the required functionality to interoperate

 *  closely with the Vault contract. This contract should be inherited and the

 *  abstract methods implemented to adapt the Strategy to the particular needs

 *  it has to create a return.

 *

 *  Of special interest is the relationship between `harvest()` and

 *  `vault.report()'. `harvest()` may be called simply because enough time has

 *  elapsed since the last report, and not because any funds need to be moved

 *  or positions adjusted. This is critical so that the Vault may maintain an

 *  accurate picture of the Strategy's performance. See  `vault.report()`,

 *  `harvest()`, and `harvestTrigger()` for further details.

 */

abstract contract BaseStrategy {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;
    string public metadataURI;

    // health checks
    bool public doHealthCheck;
    address public healthCheck;

    /**

     * @notice

     *  Used to track which version of `StrategyAPI` this Strategy

     *  implements.

     * @dev The Strategy's version must match the Vault's `API_VERSION`.

     * @return A string which holds the current API version of this contract.

     */
    function apiVersion() public pure returns (string memory) {
        return "0.4.3";
    }

    /**

     * @notice This Strategy's name.

     * @dev

     *  You can use this field to manage the "version" of this Strategy, e.g.

     *  `StrategySomethingOrOtherV1`. However, "API Version" is managed by

     *  `apiVersion()` function above.

     * @return This Strategy's name.

     */
    function name() external view virtual returns (string memory);

    /**

     * @notice

     *  The amount (priced in want) of the total assets managed by this strategy should not count

     *  towards Yearn's TVL calculations.

     * @dev

     *  You can override this field to set it to a non-zero value if some of the assets of this

     *  Strategy is somehow delegated inside another part of of Yearn's ecosystem e.g. another Vault.

     *  Note that this value must be strictly less than or equal to the amount provided by

     *  `estimatedTotalAssets()` below, as the TVL calc will be total assets minus delegated assets.

     *  Also note that this value is used to determine the total assets under management by this

     *  strategy, for the purposes of computing the management fee in `Vault`

     * @return

     *  The amount of assets this strategy manages that should not be included in Yearn's Total Value

     *  Locked (TVL) calculation across it's ecosystem.

     */
    function delegatedAssets() external view virtual returns (uint256) {
        return 0;
    }

    VaultAPI public vault;
    address public strategist;
    address public rewards;
    address public keeper;

    IERC20 public want;

    // So indexers can keep track of this
    event Harvested(uint256 profit, uint256 loss, uint256 debtPayment, uint256 debtOutstanding);

    event UpdatedStrategist(address newStrategist);

    event UpdatedKeeper(address newKeeper);

    event UpdatedRewards(address rewards);

    event UpdatedMinReportDelay(uint256 delay);

    event UpdatedMaxReportDelay(uint256 delay);

    event UpdatedProfitFactor(uint256 profitFactor);

    event UpdatedDebtThreshold(uint256 debtThreshold);

    event EmergencyExitEnabled();

    event UpdatedMetadataURI(string metadataURI);

    event SetHealthCheck(address);
    event SetDoHealthCheck(bool);

    // The minimum number of seconds between harvest calls. See
    // `setMinReportDelay()` for more details.
    uint256 public minReportDelay;

    // The maximum number of seconds between harvest calls. See
    // `setMaxReportDelay()` for more details.
    uint256 public maxReportDelay;

    // The minimum multiple that `callCost` must be above the credit/profit to
    // be "justifiable". See `setProfitFactor()` for more details.
    uint256 public profitFactor;

    // Use this to adjust the threshold at which running a debt causes a
    // harvest trigger. See `setDebtThreshold()` for more details.
    uint256 public debtThreshold;

    // See note on `setEmergencyExit()`.
    bool public emergencyExit;

    // modifiers
    modifier onlyAuthorized() {
        require(msg.sender == strategist || msg.sender == governance(), "!authorized");
        _;
    }

    modifier onlyEmergencyAuthorized() {
        require(
            msg.sender == strategist || msg.sender == governance() || msg.sender == vault.guardian() || msg.sender == vault.management(),
            "!authorized"
        );
        _;
    }

    modifier onlyStrategist() {
        require(msg.sender == strategist, "!strategist");
        _;
    }

    modifier onlyGovernance() {
        require(msg.sender == governance(), "!authorized");
        _;
    }

    modifier onlyKeepers() {
        require(
            msg.sender == keeper ||
                msg.sender == strategist ||
                msg.sender == governance() ||
                msg.sender == vault.guardian() ||
                msg.sender == vault.management(),
            "!authorized"
        );
        _;
    }

    modifier onlyVaultManagers() {
        require(msg.sender == vault.management() || msg.sender == governance(), "!authorized");
        _;
    }

    constructor(address _vault) public {
        _initialize(_vault, msg.sender, msg.sender, msg.sender);
    }

    /**

     * @notice

     *  Initializes the Strategy, this is called only once, when the

     *  contract is deployed.

     * @dev `_vault` should implement `VaultAPI`.

     * @param _vault The address of the Vault responsible for this Strategy.

     * @param _strategist The address to assign as `strategist`.

     * The strategist is able to change the reward address

     * @param _rewards  The address to use for pulling rewards.

     * @param _keeper The adddress of the _keeper. _keeper

     * can harvest and tend a strategy.

     */
    function _initialize(

        address _vault,

        address _strategist,

        address _rewards,

        address _keeper

    ) internal {
        require(address(want) == address(0), "Strategy already initialized");

        vault = VaultAPI(_vault);
        want = IERC20(vault.token());
        want.safeApprove(_vault, uint256(-1)); // Give Vault unlimited access (might save gas)
        strategist = _strategist;
        rewards = _rewards;
        keeper = _keeper;

        // initialize variables
        minReportDelay = 0;
        maxReportDelay = 86400;
        profitFactor = 100;
        debtThreshold = 0;

        vault.approve(rewards, uint256(-1)); // Allow rewards to be pulled
    }

    function setHealthCheck(address _healthCheck) external onlyVaultManagers {
        emit SetHealthCheck(_healthCheck);
        healthCheck = _healthCheck;
    }

    function setDoHealthCheck(bool _doHealthCheck) external onlyVaultManagers {
        emit SetDoHealthCheck(_doHealthCheck);
        doHealthCheck = _doHealthCheck;
    }

    /**

     * @notice

     *  Used to change `strategist`.

     *

     *  This may only be called by governance or the existing strategist.

     * @param _strategist The new address to assign as `strategist`.

     */
    function setStrategist(address _strategist) external onlyAuthorized {
        require(_strategist != address(0));
        strategist = _strategist;
        emit UpdatedStrategist(_strategist);
    }

    /**

     * @notice

     *  Used to change `keeper`.

     *

     *  `keeper` is the only address that may call `tend()` or `harvest()`,

     *  other than `governance()` or `strategist`. However, unlike

     *  `governance()` or `strategist`, `keeper` may *only* call `tend()`

     *  and `harvest()`, and no other authorized functions, following the

     *  principle of least privilege.

     *

     *  This may only be called by governance or the strategist.

     * @param _keeper The new address to assign as `keeper`.

     */
    function setKeeper(address _keeper) external onlyAuthorized {
        require(_keeper != address(0));
        keeper = _keeper;
        emit UpdatedKeeper(_keeper);
    }

    /**

     * @notice

     *  Used to change `rewards`. EOA or smart contract which has the permission

     *  to pull rewards from the vault.

     *

     *  This may only be called by the strategist.

     * @param _rewards The address to use for pulling rewards.

     */
    function setRewards(address _rewards) external onlyStrategist {
        require(_rewards != address(0));
        vault.approve(rewards, 0);
        rewards = _rewards;
        vault.approve(rewards, uint256(-1));
        emit UpdatedRewards(_rewards);
    }

    /**

     * @notice

     *  Used to change `minReportDelay`. `minReportDelay` is the minimum number

     *  of blocks that should pass for `harvest()` to be called.

     *

     *  For external keepers (such as the Keep3r network), this is the minimum

     *  time between jobs to wait. (see `harvestTrigger()`

     *  for more details.)

     *

     *  This may only be called by governance or the strategist.

     * @param _delay The minimum number of seconds to wait between harvests.

     */
    function setMinReportDelay(uint256 _delay) external onlyAuthorized {
        minReportDelay = _delay;
        emit UpdatedMinReportDelay(_delay);
    }

    /**

     * @notice

     *  Used to change `maxReportDelay`. `maxReportDelay` is the maximum number

     *  of blocks that should pass for `harvest()` to be called.

     *

     *  For external keepers (such as the Keep3r network), this is the maximum

     *  time between jobs to wait. (see `harvestTrigger()`

     *  for more details.)

     *

     *  This may only be called by governance or the strategist.

     * @param _delay The maximum number of seconds to wait between harvests.

     */
    function setMaxReportDelay(uint256 _delay) external onlyAuthorized {
        maxReportDelay = _delay;
        emit UpdatedMaxReportDelay(_delay);
    }

    /**

     * @notice

     *  Used to change `profitFactor`. `profitFactor` is used to determine

     *  if it's worthwhile to harvest, given gas costs. (See `harvestTrigger()`

     *  for more details.)

     *

     *  This may only be called by governance or the strategist.

     * @param _profitFactor A ratio to multiply anticipated

     * `harvest()` gas cost against.

     */
    function setProfitFactor(uint256 _profitFactor) external onlyAuthorized {
        profitFactor = _profitFactor;
        emit UpdatedProfitFactor(_profitFactor);
    }

    /**

     * @notice

     *  Sets how far the Strategy can go into loss without a harvest and report

     *  being required.

     *

     *  By default this is 0, meaning any losses would cause a harvest which

     *  will subsequently report the loss to the Vault for tracking. (See

     *  `harvestTrigger()` for more details.)

     *

     *  This may only be called by governance or the strategist.

     * @param _debtThreshold How big of a loss this Strategy may carry without

     * being required to report to the Vault.

     */
    function setDebtThreshold(uint256 _debtThreshold) external onlyAuthorized {
        debtThreshold = _debtThreshold;
        emit UpdatedDebtThreshold(_debtThreshold);
    }

    /**

     * @notice

     *  Used to change `metadataURI`. `metadataURI` is used to store the URI

     * of the file describing the strategy.

     *

     *  This may only be called by governance or the strategist.

     * @param _metadataURI The URI that describe the strategy.

     */
    function setMetadataURI(string calldata _metadataURI) external onlyAuthorized {
        metadataURI = _metadataURI;
        emit UpdatedMetadataURI(_metadataURI);
    }

    /**

     * Resolve governance address from Vault contract, used to make assertions

     * on protected functions in the Strategy.

     */
    function governance() internal view returns (address) {
        return vault.governance();
    }

    /**

     * @notice

     *  Provide an accurate conversion from `_amtInWei` (denominated in wei)

     *  to `want` (using the native decimal characteristics of `want`).

     * @dev

     *  Care must be taken when working with decimals to assure that the conversion

     *  is compatible. As an example:

     *

     *      given 1e17 wei (0.1 ETH) as input, and want is USDC (6 decimals),

     *      with USDC/ETH = 1800, this should give back 1800000000 (180 USDC)

     *

     * @param _amtInWei The amount (in wei/1e-18 ETH) to convert to `want`

     * @return The amount in `want` of `_amtInEth` converted to `want`

     **/
    function ethToWant(uint256 _amtInWei) public view virtual returns (uint256);

    /**

     * @notice

     *  Provide an accurate estimate for the total amount of assets

     *  (principle + return) that this Strategy is currently managing,

     *  denominated in terms of `want` tokens.

     *

     *  This total should be "realizable" e.g. the total value that could

     *  *actually* be obtained from this Strategy if it were to divest its

     *  entire position based on current on-chain conditions.

     * @dev

     *  Care must be taken in using this function, since it relies on external

     *  systems, which could be manipulated by the attacker to give an inflated

     *  (or reduced) value produced by this function, based on current on-chain

     *  conditions (e.g. this function is possible to influence through

     *  flashloan attacks, oracle manipulations, or other DeFi attack

     *  mechanisms).

     *

     *  It is up to governance to use this function to correctly order this

     *  Strategy relative to its peers in the withdrawal queue to minimize

     *  losses for the Vault based on sudden withdrawals. This value should be

     *  higher than the total debt of the Strategy and higher than its expected

     *  value to be "safe".

     * @return The estimated total assets in this Strategy.

     */
    function estimatedTotalAssets() public view virtual returns (uint256);

    /*

     * @notice

     *  Provide an indication of whether this strategy is currently "active"

     *  in that it is managing an active position, or will manage a position in

     *  the future. This should correlate to `harvest()` activity, so that Harvest

     *  events can be tracked externally by indexing agents.

     * @return True if the strategy is actively managing a position.

     */
    function isActive() public view returns (bool) {
        return vault.strategies(address(this)).debtRatio > 0 || estimatedTotalAssets() > 0;
    }

    /**

     * Perform any Strategy unwinding or other calls necessary to capture the

     * "free return" this Strategy has generated since the last time its core

     * position(s) were adjusted. Examples include unwrapping extra rewards.

     * This call is only used during "normal operation" of a Strategy, and

     * should be optimized to minimize losses as much as possible.

     *

     * This method returns any realized profits and/or realized losses

     * incurred, and should return the total amounts of profits/losses/debt

     * payments (in `want` tokens) for the Vault's accounting (e.g.

     * `want.balanceOf(this) >= _debtPayment + _profit`).

     *

     * `_debtOutstanding` will be 0 if the Strategy is not past the configured

     * debt limit, otherwise its value will be how far past the debt limit

     * the Strategy is. The Strategy's debt limit is configured in the Vault.

     *

     * NOTE: `_debtPayment` should be less than or equal to `_debtOutstanding`.

     *       It is okay for it to be less than `_debtOutstanding`, as that

     *       should only used as a guide for how much is left to pay back.

     *       Payments should be made to minimize loss from slippage, debt,

     *       withdrawal fees, etc.

     *

     * See `vault.debtOutstanding()`.

     */
    function prepareReturn(uint256 _debtOutstanding)

        internal

        virtual

        returns (

            uint256 _profit,

            uint256 _loss,

            uint256 _debtPayment

        );

    /**

     * Perform any adjustments to the core position(s) of this Strategy given

     * what change the Vault made in the "investable capital" available to the

     * Strategy. Note that all "free capital" in the Strategy after the report

     * was made is available for reinvestment. Also note that this number

     * could be 0, and you should handle that scenario accordingly.

     *

     * See comments regarding `_debtOutstanding` on `prepareReturn()`.

     */
    function adjustPosition(uint256 _debtOutstanding) internal virtual;

    /**

     * Liquidate up to `_amountNeeded` of `want` of this strategy's positions,

     * irregardless of slippage. Any excess will be re-invested with `adjustPosition()`.

     * This function should return the amount of `want` tokens made available by the

     * liquidation. If there is a difference between them, `_loss` indicates whether the

     * difference is due to a realized loss, or if there is some other sitution at play

     * (e.g. locked funds) where the amount made available is less than what is needed.

     *

     * NOTE: The invariant `_liquidatedAmount + _loss <= _amountNeeded` should always be maintained

     */
    function liquidatePosition(uint256 _amountNeeded) internal virtual returns (uint256 _liquidatedAmount, uint256 _loss);

    /**

     * Liquidate everything and returns the amount that got freed.

     * This function is used during emergency exit instead of `prepareReturn()` to

     * liquidate all of the Strategy's positions back to the Vault.

     */

    function liquidateAllPositions() internal virtual returns (uint256 _amountFreed);

    /**

     * @notice

     *  Provide a signal to the keeper that `tend()` should be called. The

     *  keeper will provide the estimated gas cost that they would pay to call

     *  `tend()`, and this function should use that estimate to make a

     *  determination if calling it is "worth it" for the keeper. This is not

     *  the only consideration into issuing this trigger, for example if the

     *  position would be negatively affected if `tend()` is not called

     *  shortly, then this can return `true` even if the keeper might be

     *  "at a loss" (keepers are always reimbursed by Yearn).

     * @dev

     *  `callCostInWei` must be priced in terms of `wei` (1e-18 ETH).

     *

     *  This call and `harvestTrigger()` should never return `true` at the same

     *  time.

     * @param callCostInWei The keeper's estimated gas cost to call `tend()` (in wei).

     * @return `true` if `tend()` should be called, `false` otherwise.

     */
    function tendTrigger(uint256 callCostInWei) public view virtual returns (bool) {
        // We usually don't need tend, but if there are positions that need
        // active maintainence, overriding this function is how you would
        // signal for that.
        // If your implementation uses the cost of the call in want, you can
        // use uint256 callCost = ethToWant(callCostInWei);

        return false;
    }

    /**

     * @notice

     *  Adjust the Strategy's position. The purpose of tending isn't to

     *  realize gains, but to maximize yield by reinvesting any returns.

     *

     *  See comments on `adjustPosition()`.

     *

     *  This may only be called by governance, the strategist, or the keeper.

     */
    function tend() external onlyKeepers {
        // Don't take profits with this call, but adjust for better gains
        adjustPosition(vault.debtOutstanding());
    }

    /**

     * @notice

     *  Provide a signal to the keeper that `harvest()` should be called. The

     *  keeper will provide the estimated gas cost that they would pay to call

     *  `harvest()`, and this function should use that estimate to make a

     *  determination if calling it is "worth it" for the keeper. This is not

     *  the only consideration into issuing this trigger, for example if the

     *  position would be negatively affected if `harvest()` is not called

     *  shortly, then this can return `true` even if the keeper might be "at a

     *  loss" (keepers are always reimbursed by Yearn).

     * @dev

     *  `callCostInWei` must be priced in terms of `wei` (1e-18 ETH).

     *

     *  This call and `tendTrigger` should never return `true` at the

     *  same time.

     *

     *  See `min/maxReportDelay`, `profitFactor`, `debtThreshold` to adjust the

     *  strategist-controlled parameters that will influence whether this call

     *  returns `true` or not. These parameters will be used in conjunction

     *  with the parameters reported to the Vault (see `params`) to determine

     *  if calling `harvest()` is merited.

     *

     *  It is expected that an external system will check `harvestTrigger()`.

     *  This could be a script run off a desktop or cloud bot (e.g.

     *  https://github.com/iearn-finance/yearn-vaults/blob/main/scripts/keep.py),

     *  or via an integration with the Keep3r network (e.g.

     *  https://github.com/Macarse/GenericKeep3rV2/blob/master/contracts/keep3r/GenericKeep3rV2.sol).

     * @param callCostInWei The keeper's estimated gas cost to call `harvest()` (in wei).

     * @return `true` if `harvest()` should be called, `false` otherwise.

     */
    function harvestTrigger(uint256 callCostInWei) public view virtual returns (bool) {
        uint256 callCost = ethToWant(callCostInWei);
        StrategyParams memory params = vault.strategies(address(this));

        // Should not trigger if Strategy is not activated
        if (params.activation == 0) return false;

        // Should not trigger if we haven't waited long enough since previous harvest
        if (block.timestamp.sub(params.lastReport) < minReportDelay) return false;

        // Should trigger if hasn't been called in a while
        if (block.timestamp.sub(params.lastReport) >= maxReportDelay) return true;

        // If some amount is owed, pay it back
        // NOTE: Since debt is based on deposits, it makes sense to guard against large
        //       changes to the value from triggering a harvest directly through user
        //       behavior. This should ensure reasonable resistance to manipulation
        //       from user-initiated withdrawals as the outstanding debt fluctuates.
        uint256 outstanding = vault.debtOutstanding();
        if (outstanding > debtThreshold) return true;

        // Check for profits and losses
        uint256 total = estimatedTotalAssets();
        // Trigger if we have a loss to report
        if (total.add(debtThreshold) < params.totalDebt) return true;

        uint256 profit = 0;
        if (total > params.totalDebt) profit = total.sub(params.totalDebt); // We've earned a profit!

        // Otherwise, only trigger if it "makes sense" economically (gas cost
        // is <N% of value moved)
        uint256 credit = vault.creditAvailable();
        return (profitFactor.mul(callCost) < credit.add(profit));
    }

    /**

     * @notice

     *  Harvests the Strategy, recognizing any profits or losses and adjusting

     *  the Strategy's position.

     *

     *  In the rare case the Strategy is in emergency shutdown, this will exit

     *  the Strategy's position.

     *

     *  This may only be called by governance, the strategist, or the keeper.

     * @dev

     *  When `harvest()` is called, the Strategy reports to the Vault (via

     *  `vault.report()`), so in some cases `harvest()` must be called in order

     *  to take in profits, to borrow newly available funds from the Vault, or

     *  otherwise adjust its position. In other cases `harvest()` must be

     *  called to report to the Vault on the Strategy's position, especially if

     *  any losses have occurred.

     */
    function harvest() external onlyKeepers {
        uint256 profit = 0;
        uint256 loss = 0;
        uint256 debtOutstanding = vault.debtOutstanding();
        uint256 debtPayment = 0;
        if (emergencyExit) {
            // Free up as much capital as possible
            uint256 amountFreed = liquidateAllPositions();
            if (amountFreed < debtOutstanding) {
                loss = debtOutstanding.sub(amountFreed);
            } else if (amountFreed > debtOutstanding) {
                profit = amountFreed.sub(debtOutstanding);
            }
            debtPayment = debtOutstanding.sub(loss);
        } else {
            // Free up returns for Vault to pull
            (profit, loss, debtPayment) = prepareReturn(debtOutstanding);
        }

        // Allow Vault to take up to the "harvested" balance of this contract,
        // which is the amount it has earned since the last time it reported to
        // the Vault.
        uint256 totalDebt = vault.strategies(address(this)).totalDebt;
        debtOutstanding = vault.report(profit, loss, debtPayment);

        // Check if free returns are left, and re-invest them
        adjustPosition(debtOutstanding);

        // call healthCheck contract
        if (doHealthCheck && healthCheck != address(0)) {
            require(HealthCheck(healthCheck).check(profit, loss, debtPayment, debtOutstanding, totalDebt), "!healthcheck");
        } else {
            emit SetDoHealthCheck(true);
            doHealthCheck = true;
        }

        emit Harvested(profit, loss, debtPayment, debtOutstanding);
    }

    /**

     * @notice

     *  Withdraws `_amountNeeded` to `vault`.

     *

     *  This may only be called by the Vault.

     * @param _amountNeeded How much `want` to withdraw.

     * @return _loss Any realized losses

     */
    function withdraw(uint256 _amountNeeded) external returns (uint256 _loss) {
        require(msg.sender == address(vault), "!vault");
        // Liquidate as much as possible to `want`, up to `_amountNeeded`
        uint256 amountFreed;
        (amountFreed, _loss) = liquidatePosition(_amountNeeded);
        // Send it directly back (NOTE: Using `msg.sender` saves some gas here)
        want.safeTransfer(msg.sender, amountFreed);
        // NOTE: Reinvest anything leftover on next `tend`/`harvest`
    }

    /**

     * Do anything necessary to prepare this Strategy for migration, such as

     * transferring any reserve or LP tokens, CDPs, or other tokens or stores of

     * value.

     */
    function prepareMigration(address _newStrategy) internal virtual;

    /**

     * @notice

     *  Transfers all `want` from this Strategy to `_newStrategy`.

     *

     *  This may only be called by the Vault.

     * @dev

     * The new Strategy's Vault must be the same as this Strategy's Vault.

     *  The migration process should be carefully performed to make sure all

     * the assets are migrated to the new address, which should have never

     * interacted with the vault before.

     * @param _newStrategy The Strategy to migrate to.

     */
    function migrate(address _newStrategy) external {
        require(msg.sender == address(vault));
        require(BaseStrategy(_newStrategy).vault() == vault);
        prepareMigration(_newStrategy);
        want.safeTransfer(_newStrategy, want.balanceOf(address(this)));
    }

    /**

     * @notice

     *  Activates emergency exit. Once activated, the Strategy will exit its

     *  position upon the next harvest, depositing all funds into the Vault as

     *  quickly as is reasonable given on-chain conditions.

     *

     *  This may only be called by governance or the strategist.

     * @dev

     *  See `vault.setEmergencyShutdown()` and `harvest()` for further details.

     */
    function setEmergencyExit() external onlyEmergencyAuthorized {
        emergencyExit = true;
        vault.revokeStrategy();

        emit EmergencyExitEnabled();
    }

    /**

     * Override this to add all tokens/tokenized positions this contract

     * manages on a *persistent* basis (e.g. not just for swapping back to

     * want ephemerally).

     *

     * NOTE: Do *not* include `want`, already included in `sweep` below.

     *

     * Example:

     * ```

     *    function protectedTokens() internal override view returns (address[] memory) {

     *      address[] memory protected = new address[](3);

     *      protected[0] = tokenA;

     *      protected[1] = tokenB;

     *      protected[2] = tokenC;

     *      return protected;

     *    }

     * ```

     */
    function protectedTokens() internal view virtual returns (address[] memory);

    /**

     * @notice

     *  Removes tokens from this Strategy that are not the type of tokens

     *  managed by this Strategy. This may be used in case of accidentally

     *  sending the wrong kind of token to this Strategy.

     *

     *  Tokens will be sent to `governance()`.

     *

     *  This will fail if an attempt is made to sweep `want`, or any tokens

     *  that are protected by this Strategy.

     *

     *  This may only be called by governance.

     * @dev

     *  Implement `protectedTokens()` to specify any additional tokens that

     *  should be protected from sweeping in addition to `want`.

     * @param _token The token to transfer out of this vault.

     */
    function sweep(address _token) external onlyGovernance {
        require(_token != address(want), "!want");
        require(_token != address(vault), "!shares");

        address[] memory _protectedTokens = protectedTokens();
        for (uint256 i; i < _protectedTokens.length; i++) require(_token != _protectedTokens[i], "!protected");

        IERC20(_token).safeTransfer(governance(), IERC20(_token).balanceOf(address(this)));
    }
}

abstract contract BaseStrategyInitializable is BaseStrategy {
    bool public isOriginal = true;
    event Cloned(address indexed clone);

    constructor(address _vault) public BaseStrategy(_vault) {}

    function initialize(

        address _vault,

        address _strategist,

        address _rewards,

        address _keeper

    ) external virtual {
        _initialize(_vault, _strategist, _rewards, _keeper);
    }

    function clone(address _vault) external returns (address) {
        require(isOriginal, "!clone");
        return this.clone(_vault, msg.sender, msg.sender, msg.sender);
    }

    function clone(

        address _vault,

        address _strategist,

        address _rewards,

        address _keeper

    ) external returns (address newStrategy) {
        // Copied from https://github.com/optionality/clone-factory/blob/master/contracts/CloneFactory.sol
        bytes20 addressBytes = bytes20(address(this));

        assembly {
            // EIP-1167 bytecode
            let clone_code := mload(0x40)
            mstore(clone_code, 0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000)
            mstore(add(clone_code, 0x14), addressBytes)
            mstore(add(clone_code, 0x28), 0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000)
            newStrategy := create(0, clone_code, 0x37)
        }

        BaseStrategyInitializable(newStrategy).initialize(_vault, _strategist, _rewards, _keeper);

        emit Cloned(newStrategy);
    }
}

// File: curve.sol

interface IGauge {
    function deposit(uint256) external;

    function balanceOf(address) external view returns (uint256);

    function claim_rewards() external;

    function claimable_tokens(address) external view returns (uint256);

    function claimable_reward(address _addressToCheck, address _rewardToken)

        external

        view

        returns (uint256);

    function withdraw(uint256) external;
}

interface ICurveFi {
    function get_virtual_price() external view returns (uint256);

    function add_liquidity(

        // EURt

        uint256[2] calldata amounts,

        uint256 min_mint_amount

    ) external payable;

    function add_liquidity(

        // Compound, sAave

        uint256[2] calldata amounts,

        uint256 min_mint_amount,

        bool _use_underlying

    ) external payable returns (uint256);

    function add_liquidity(

        // Iron Bank, Aave

        uint256[3] calldata amounts,

        uint256 min_mint_amount,

        bool _use_underlying

    ) external payable returns (uint256);

    function add_liquidity(

        // 3Crv Metapools

        address pool,

        uint256[4] calldata amounts,

        uint256 min_mint_amount

    ) external;

    function add_liquidity(

        // Y and yBUSD

        uint256[4] calldata amounts,

        uint256 min_mint_amount,

        bool _use_underlying

    ) external payable returns (uint256);

    function add_liquidity(

        // 3pool

        uint256[3] calldata amounts,

        uint256 min_mint_amount

    ) external payable;

    function add_liquidity(

        // sUSD

        uint256[4] calldata amounts,

        uint256 min_mint_amount

    ) external payable;

    function remove_liquidity_imbalance(

        uint256[2] calldata amounts,

        uint256 max_burn_amount

    ) external;

    function remove_liquidity(uint256 _amount, uint256[2] calldata amounts)

        external;

    function remove_liquidity_one_coin(

        uint256 _token_amount,

        int128 i,

        uint256 min_amount

    ) external;

    function exchange(

        // CRV-ETH and CVX-ETH

        uint256 from,

        uint256 to,

        uint256 _from_amount,

        uint256 _min_to_amount,

        bool use_eth

    ) external;

    function exchange(

        // sETH

        int128 from,

        int128 to,

        uint256 _from_amount,

        uint256 _min_to_amount

    ) external payable returns (uint256);

    function balances(uint256) external view returns (uint256);

    function price_oracle() external view returns (uint256);

    function get_dy(

        int128 from,

        int128 to,

        uint256 _from_amount

    ) external view returns (uint256);

    // EURt
    function calc_token_amount(uint256[2] calldata _amounts, bool _is_deposit)

        external

        view

        returns (uint256);

    // 3Crv Metapools
    function calc_token_amount(

        address _pool,

        uint256[4] calldata _amounts,

        bool _is_deposit

    ) external view returns (uint256);

    // sUSD, Y pool, etc
    function calc_token_amount(uint256[4] calldata _amounts, bool _is_deposit)

        external

        view

        returns (uint256);

    // 3pool, Iron Bank, etc
    function calc_token_amount(uint256[3] calldata _amounts, bool _is_deposit)

        external

        view

        returns (uint256);

    function calc_withdraw_one_coin(uint256 amount, int128 i)

        external

        view

        returns (uint256);
}

interface ICrvV3 is IERC20 {
    function minter() external view returns (address);
}

interface IMinter {
    function mint(address) external;
}

// File: StrategyConvexsBTCMetapoolsOldClonable.sol

// These are the core Yearn libraries

interface IBaseFee {
    function isCurrentBaseFeeAcceptable() external view returns (bool);
}

interface IOracle {
    function latestAnswer() external view returns (uint256);
}

interface IUniV3 {
    struct ExactInputParams {
        bytes path;
        address recipient;
        uint256 deadline;
        uint256 amountIn;
        uint256 amountOutMinimum;
    }

    function exactInput(ExactInputParams calldata params)

        external

        payable

        returns (uint256 amountOut);
}

interface IConvexRewards {
    // strategy's staked balance in the synthetix staking contract
    function balanceOf(address account) external view returns (uint256);

    // read how much claimable CRV a strategy has
    function earned(address account) external view returns (uint256);

    // stake a convex tokenized deposit
    function stake(uint256 _amount) external returns (bool);

    // withdraw to a convex tokenized deposit, probably never need to use this
    function withdraw(uint256 _amount, bool _claim) external returns (bool);

    // withdraw directly to curve LP token, this is what we primarily use
    function withdrawAndUnwrap(uint256 _amount, bool _claim)

        external

        returns (bool);

    // claim rewards, with an option to claim extra rewards or not
    function getReward(address _account, bool _claimExtras)

        external

        returns (bool);

    // check if we have rewards on a pool
    function extraRewardsLength() external view returns (uint256);

    // if we have rewards, see what the address is
    function extraRewards(uint256 _reward) external view returns (address);

    // read our rewards token
    function rewardToken() external view returns (address);

    // check our reward period finish
    function periodFinish() external view returns (uint256);
}

interface IConvexDeposit {
    // deposit into convex, receive a tokenized deposit.  parameter to stake immediately (we always do this).
    function deposit(

        uint256 _pid,

        uint256 _amount,

        bool _stake

    ) external returns (bool);

    // burn a tokenized deposit (Convex deposit tokens) to receive curve lp tokens back
    function withdraw(uint256 _pid, uint256 _amount) external returns (bool);

    // give us info about a pool based on its pid
    function poolInfo(uint256)

        external

        view

        returns (

            address,

            address,

            address,

            address,

            address,

            bool

        );
}

abstract contract StrategyConvexBase is BaseStrategy {
    using Address for address;

    /* ========== STATE VARIABLES ========== */
    // these should stay the same across different wants.

    // convex stuff
    address internal constant depositContract =
        0xF403C135812408BFbE8713b5A23a04b3D48AAE31; // this is the deposit contract that all pools use, aka booster
    IConvexRewards public rewardsContract; // This is unique to each curve pool
    address public virtualRewardsPool; // This is only if we have bonus rewards
    uint256 public pid; // this is unique to each pool

    // keepCRV stuff
    uint256 public keepCRV; // the percentage of CRV we re-lock for boost (in basis points)
    uint256 public keepCVX; // the percentage of CVX we keep for boosting yield (in basis points)
    address public keepCVXDestination; // where we send the CVX we are keeping
    address internal constant voter =
        0xF147b8125d2ef93FB6965Db97D6746952a133934; // Yearn's veCRV voter, we send some extra CRV here
    uint256 internal constant FEE_DENOMINATOR = 10000; // this means all of our fee values are in basis points

    // Swap stuff
    address internal constant sushiswap =
        0xd9e1cE17f2641f24aE83637ab66a2cca9C378B9F; // we use this to sell our bonus token mostly
    address internal constant uniswapV2 =
        0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D; // use this for weird tokens with more liquidity on UniV2
    address public router; // the router selected to sell our bonus token

    IERC20 internal constant crv =
        IERC20(0xD533a949740bb3306d119CC777fa900bA034cd52);
    IERC20 internal constant convexToken =
        IERC20(0x4e3FBD56CD56c3e72c1403e103b45Db9da5B9D2B);
    IERC20 internal constant weth =
        IERC20(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);

    // keeper stuff
    uint256 public harvestProfitMin; // minimum size in USD (6 decimals) that we want to harvest
    uint256 public harvestProfitMax; // maximum size in USD (6 decimals) that we want to harvest
    uint256 public creditThreshold; // amount of credit in underlying tokens that will automatically trigger a harvest
    bool internal forceHarvestTriggerOnce; // only set this to true when we want to trigger our keepers to harvest for us

    string internal stratName;

    // convex-specific variables
    bool public claimRewards; // boolean if we should always claim rewards when withdrawing, usually via withdrawAndUnwrap (generally this should be false)

    /* ========== CONSTRUCTOR ========== */

    constructor(address _vault) public BaseStrategy(_vault) {}

    /* ========== VIEWS ========== */

    function name() external view override returns (string memory) {
        return stratName;
    }

    /// @notice How much want we have staked in Convex
    function stakedBalance() public view returns (uint256) {
        return rewardsContract.balanceOf(address(this));
    }

    /// @notice Balance of want sitting in our strategy
    function balanceOfWant() public view returns (uint256) {
        return want.balanceOf(address(this));
    }

    /// @notice How much CRV we can claim from the staking contract
    function claimableBalance() public view returns (uint256) {
        return rewardsContract.earned(address(this));
    }

    function estimatedTotalAssets() public view override returns (uint256) {
        return balanceOfWant().add(stakedBalance());
    }

    /* ========== MUTATIVE FUNCTIONS ========== */

    function adjustPosition(uint256 _debtOutstanding) internal override {
        if (emergencyExit) {
            return;
        }
        // Send all of our Curve pool tokens to be deposited
        uint256 _toInvest = balanceOfWant();
        // deposit into convex and stake immediately (but only if we have something to invest)
        if (_toInvest > 0) {
            IConvexDeposit(depositContract).deposit(pid, _toInvest, true);
        }
    }

    function liquidatePosition(uint256 _amountNeeded)

        internal

        override

        returns (uint256 _liquidatedAmount, uint256 _loss)

    {
        uint256 _wantBal = balanceOfWant();
        if (_amountNeeded > _wantBal) {
            uint256 _stakedBal = stakedBalance();
            if (_stakedBal > 0) {
                rewardsContract.withdrawAndUnwrap(
                    Math.min(_stakedBal, _amountNeeded.sub(_wantBal)),
                    claimRewards
                );
            }
            uint256 _withdrawnBal = balanceOfWant();
            _liquidatedAmount = Math.min(_amountNeeded, _withdrawnBal);
            _loss = _amountNeeded.sub(_liquidatedAmount);
        } else {
            // we have enough balance to cover the liquidation available
            return (_amountNeeded, 0);
        }
    }

    // fire sale, get rid of it all!
    function liquidateAllPositions() internal override returns (uint256) {
        uint256 _stakedBal = stakedBalance();
        if (_stakedBal > 0) {
            // don't bother withdrawing zero
            rewardsContract.withdrawAndUnwrap(_stakedBal, claimRewards);
        }
        return balanceOfWant();
    }

    // in case we need to exit into the convex deposit token, this will allow us to do that
    // make sure to check claimRewards before this step if needed
    // plan to have gov sweep convex deposit tokens from strategy after this
    function withdrawToConvexDepositTokens() external onlyVaultManagers {
        uint256 _stakedBal = stakedBalance();
        if (_stakedBal > 0) {
            rewardsContract.withdraw(_stakedBal, claimRewards);
        }
    }

    // we don't want for these tokens to be swept out. We allow gov to sweep out cvx vault tokens; we would only be holding these if things were really, really rekt.
    function protectedTokens()

        internal

        view

        override

        returns (address[] memory)

    {}

    /* ========== SETTERS ========== */

    // These functions are useful for setting parameters of the strategy that may need to be adjusted.

    // Set the amount of CRV to be locked in Yearn's veCRV voter from each harvest. Default is 10%. Option to keep CVX as well.
    function setKeep(

        uint256 _keepCRV,

        uint256 _keepCVX,

        address _keepCVXDestination

    ) external onlyGovernance {
        require(_keepCRV <= 10_000 && _keepCVX <= 10_000);
        keepCRV = _keepCRV;
        keepCVX = _keepCVX;
        keepCVXDestination = _keepCVXDestination;
    }

    // We usually don't need to claim rewards on withdrawals, but might change our mind for migrations etc
    function setClaimRewards(bool _claimRewards) external onlyVaultManagers {
        claimRewards = _claimRewards;
    }

    // This allows us to manually harvest with our keeper as needed
    function setForceHarvestTriggerOnce(bool _forceHarvestTriggerOnce)

        external

        onlyVaultManagers

    {
        forceHarvestTriggerOnce = _forceHarvestTriggerOnce;
    }
}

contract StrategyConvexsBTCMetapoolsOldClonable is StrategyConvexBase {
    /* ========== STATE VARIABLES ========== */
    // these will likely change across different wants.

    // Curve stuff
    ICurveFi public curve; // Curve Pool, this is our pool specific to this vault

    bool public checkEarmark; // this determines if we should check if we need to earmark rewards before harvesting

    // use Curve to sell our CVX and CRV rewards to WETH
    ICurveFi internal constant crveth =
        ICurveFi(0x8301AE4fc9c624d1D396cbDAa1ed877821D7C511); // use curve's new CRV-ETH crypto pool to sell our CRV
    ICurveFi internal constant cvxeth =
        ICurveFi(0xB576491F1E6e5E62f1d8F26062Ee822B40B0E0d4); // use curve's new CVX-ETH crypto pool to sell our CVX

    // we use these to deposit to our curve pool
    address internal constant uniswapv3 =
        0xE592427A0AEce92De3Edee1F18E0157C05861564;
    IERC20 internal constant usdt =
        IERC20(0xdAC17F958D2ee523a2206206994597C13D831ec7);
    IERC20 internal constant wbtc =
        IERC20(0x2260FAC5E5542a773Aa44fBCfeDf7C193bc2C599);
    uint24 public uniWbtcFee; // this is equal to 0.05%, can change this later if a different path becomes more optimal

    // rewards token info. we can have more than 1 reward token but this is rare, so we don't include this in the template
    IERC20 public rewardsToken;
    bool public hasRewards;
    address[] internal rewardsPath;

    // check for cloning
    bool internal isOriginal = true;

    /* ========== CONSTRUCTOR ========== */

    constructor(
        address _vault,
        uint256 _pid,
        address _curvePool,
        string memory _name
    ) public StrategyConvexBase(_vault) {
        _initializeStrat(_pid, _curvePool, _name);
    }

    /* ========== CLONING ========== */

    event Cloned(address indexed clone);

    // we use this to clone our original strategy to other vaults
    function cloneConvexSBTCOld(

        address _vault,

        address _strategist,

        address _rewards,

        address _keeper,

        uint256 _pid,

        address _curvePool,

        string memory _name

    ) external returns (address newStrategy) {
        require(isOriginal);
        // Copied from https://github.com/optionality/clone-factory/blob/master/contracts/CloneFactory.sol
        bytes20 addressBytes = bytes20(address(this));
        assembly {
            // EIP-1167 bytecode
            let clone_code := mload(0x40)
            mstore(
                clone_code,
                0x3d602d80600a3d3981f3363d3d373d3d3d363d73000000000000000000000000
            )
            mstore(add(clone_code, 0x14), addressBytes)
            mstore(
                add(clone_code, 0x28),
                0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000
            )
            newStrategy := create(0, clone_code, 0x37)
        }

        StrategyConvexsBTCMetapoolsOldClonable(newStrategy).initialize(
            _vault,
            _strategist,
            _rewards,
            _keeper,
            _pid,
            _curvePool,
            _name
        );

        emit Cloned(newStrategy);
    }

    // this will only be called by the clone function above
    function initialize(

        address _vault,

        address _strategist,

        address _rewards,

        address _keeper,

        uint256 _pid,

        address _curvePool,

        string memory _name

    ) public {
        _initialize(_vault, _strategist, _rewards, _keeper);
        _initializeStrat(_pid, _curvePool, _name);
    }

    // this is called by our original strategy, as well as any clones
    function _initializeStrat(

        uint256 _pid,

        address _curvePool,

        string memory _name

    ) internal {
        // make sure that we haven't initialized this before
        require(address(curve) == address(0)); // already initialized.

        // You can set these parameters on deployment to whatever you want
        maxReportDelay = 100 days; // 21 days in seconds, if we hit this then harvestTrigger = True
        healthCheck = 0xDDCea799fF1699e98EDF118e0629A974Df7DF012; // health.ychad.eth
        harvestProfitMin = 10000e6;
        harvestProfitMax = 120000e6;
        creditThreshold = 10 * 1e18; // 10 BTC
        keepCRV = 1000; // default of 10%
        keepCVXDestination = 0x93A62dA5a14C80f265DAbC077fCEE437B1a0Efde; // default to treasury

        // want = Curve LP
        want.approve(address(depositContract), type(uint256).max);
        convexToken.approve(address(cvxeth), type(uint256).max);
        crv.approve(address(crveth), type(uint256).max);
        weth.approve(uniswapv3, type(uint256).max);

        // this is the pool specific to this vault
        curve = ICurveFi(_curvePool);

        // setup our rewards contract
        pid = _pid; // this is the pool ID on convex, we use this to determine what the reweardsContract address is
        (address lptoken, , , address _rewardsContract, , ) =
            IConvexDeposit(depositContract).poolInfo(_pid);

        // set up our rewardsContract
        rewardsContract = IConvexRewards(_rewardsContract);

        // check that our LP token based on our pid matches our want
        require(address(lptoken) == address(want));

        // set our strategy's name
        stratName = _name;

        // these are our approvals and path specific to this contract
        wbtc.approve(address(curve), type(uint256).max);

        // set our uniswap pool fees
        uniWbtcFee = 500;
    }

    /* ========== MUTATIVE FUNCTIONS ========== */

    function prepareReturn(uint256 _debtOutstanding)

        internal

        override

        returns (

            uint256 _profit,

            uint256 _loss,

            uint256 _debtPayment

        )

    {
        // this claims our CRV, CVX, and any extra tokens like SNX or ANKR. no harm leaving this true even if no extra rewards currently.
        rewardsContract.getReward(address(this), true);

        uint256 crvBalance = crv.balanceOf(address(this));
        uint256 convexBalance = convexToken.balanceOf(address(this));

        uint256 _sendToVoter = crvBalance.mul(keepCRV).div(FEE_DENOMINATOR);
        if (_sendToVoter > 0) {
            crv.safeTransfer(voter, _sendToVoter);
            crvBalance = crv.balanceOf(address(this));
        }

        uint256 _cvxToKeep = convexBalance.mul(keepCVX).div(FEE_DENOMINATOR);
        if (_cvxToKeep > 0) {
            convexToken.safeTransfer(keepCVXDestination, _cvxToKeep);
            convexBalance = convexToken.balanceOf(address(this));
        }

        // claim and sell our rewards if we have them
        if (hasRewards) {
            uint256 _rewardsBalance =
                IERC20(rewardsToken).balanceOf(address(this));
            if (_rewardsBalance > 0) {
                _sellRewards(_rewardsBalance);
            }
        }

        // do this even if we have zero balances so we can sell WETH from rewards
        _sellCrvAndCvx(crvBalance, convexBalance);

        // deposit our balance to Curve if we have any
        uint256 _wbtcBalance = wbtc.balanceOf(address(this));
        if (_wbtcBalance > 0) {
            curve.add_liquidity([0, 0, _wbtcBalance, 0], 0);
        }

        // debtOustanding will only be > 0 in the event of revoking or if we need to rebalance from a withdrawal or lowering the debtRatio
        if (_debtOutstanding > 0) {
            uint256 _stakedBal = stakedBalance();
            if (_stakedBal > 0) {
                rewardsContract.withdrawAndUnwrap(
                    Math.min(_stakedBal, _debtOutstanding),
                    claimRewards
                );
            }
            uint256 _withdrawnBal = balanceOfWant();
            _debtPayment = Math.min(_debtOutstanding, _withdrawnBal);
        }

        // serious loss should never happen, but if it does (for instance, if Curve is hacked), let's record it accurately
        uint256 assets = estimatedTotalAssets();
        uint256 debt = vault.strategies(address(this)).totalDebt;

        // if assets are greater than debt, things are working great!
        if (assets > debt) {
            _profit = assets.sub(debt);
            uint256 _wantBal = balanceOfWant();
            if (_profit.add(_debtPayment) > _wantBal) {
                // this should only be hit following donations to strategy
                liquidateAllPositions();
            }
        }
        // if assets are less than debt, we are in trouble
        else {
            _loss = debt.sub(assets);
        }

        // we're done harvesting, so reset our trigger if we used it
        forceHarvestTriggerOnce = false;
    }

    // migrate our want token to a new strategy if needed, make sure to check claimRewards first
    // also send over any CRV or CVX that is claimed; for migrations we definitely want to claim
    function prepareMigration(address _newStrategy) internal override {
        uint256 _stakedBal = stakedBalance();
        if (_stakedBal > 0) {
            rewardsContract.withdrawAndUnwrap(_stakedBal, claimRewards);
        }
        crv.safeTransfer(_newStrategy, crv.balanceOf(address(this)));
        convexToken.safeTransfer(
            _newStrategy,
            convexToken.balanceOf(address(this))
        );
    }

    // Sells our CRV and CVX on Curve, then WETH -> WBTC together on UniV3
    function _sellCrvAndCvx(uint256 _crvAmount, uint256 _convexAmount)

        internal

    {
        if (_convexAmount > 1e17) {
            // don't want to swap dust or we might revert
            cvxeth.exchange(1, 0, _convexAmount, 0, false);
        }

        if (_crvAmount > 1e17) {
            // don't want to swap dust or we might revert
            crveth.exchange(1, 0, _crvAmount, 0, false);
        }

        uint256 _wethBalance = weth.balanceOf(address(this));
        if (_wethBalance > 1e15) {
            // don't want to swap dust or we might revert
            IUniV3(uniswapv3).exactInput(
                IUniV3.ExactInputParams(
                    abi.encodePacked(
                        address(weth),
                        uint24(uniWbtcFee),
                        address(wbtc)
                    ),
                    address(this),
                    block.timestamp,
                    _wethBalance,
                    uint256(1)
                )
            );
        }
    }

    // Sells our harvested reward token into the selected output.
    function _sellRewards(uint256 _amount) internal {
        IUniswapV2Router02(router).swapExactTokensForTokens(
            _amount,
            uint256(0),
            rewardsPath,
            address(this),
            block.timestamp
        );
    }

    /* ========== KEEP3RS ========== */
    // use this to determine when to harvest
    function harvestTrigger(uint256 callCostinEth)

        public

        view

        override

        returns (bool)

    {
        // Should not trigger if strategy is not active (no assets and no debtRatio). This means we don't need to adjust keeper job.
        if (!isActive()) {
            return false;
        }

        // only check if we need to earmark on vaults we know are problematic
        if (checkEarmark) {
            // don't harvest if we need to earmark convex rewards
            if (needsEarmarkReward()) {
                return false;
            }
        }

        // harvest if we have a profit to claim at our upper limit without considering gas price
        uint256 claimableProfit = claimableProfitInUsdt();
        if (claimableProfit > harvestProfitMax) {
            return true;
        }

        // check if the base fee gas price is higher than we allow. if it is, block harvests.
        if (!isBaseFeeAcceptable()) {
            return false;
        }

        // trigger if we want to manually harvest, but only if our gas price is acceptable
        if (forceHarvestTriggerOnce) {
            return true;
        }

        // harvest if we have a sufficient profit to claim, but only if our gas price is acceptable
        if (claimableProfit > harvestProfitMin) {
            return true;
        }

        StrategyParams memory params = vault.strategies(address(this));
        // harvest no matter what once we reach our maxDelay
        if (block.timestamp.sub(params.lastReport) > maxReportDelay) {
            return true;
        }

        // harvest our credit if it's above our threshold
        if (vault.creditAvailable() > creditThreshold) {
            return true;
        }

        // otherwise, we don't harvest
        return false;
    }

    /// @notice The value in dollars that our claimable rewards are worth (in USDT, 6 decimals).
    function claimableProfitInUsdt() public view returns (uint256) {
        // calculations pulled directly from CVX's contract for minting CVX per CRV claimed
        uint256 totalCliffs = 1_000;
        uint256 maxSupply = 100 * 1_000_000 * 1e18; // 100mil
        uint256 reductionPerCliff = 100_000 * 1e18; // 100,000
        uint256 supply = convexToken.totalSupply();
        uint256 mintableCvx;

        uint256 cliff = supply.div(reductionPerCliff);
        uint256 _claimableBal = claimableBalance();
        //mint if below total cliffs
        if (cliff < totalCliffs) {
            //for reduction% take inverse of current cliff
            uint256 reduction = totalCliffs.sub(cliff);
            //reduce
            mintableCvx = _claimableBal.mul(reduction).div(totalCliffs);

            //supply cap check
            uint256 amtTillMax = maxSupply.sub(supply);
            if (mintableCvx > amtTillMax) {
                mintableCvx = amtTillMax;
            }
        }

        // our chainlink oracle returns prices normalized to 8 decimals, we convert it to 6
        IOracle ethOracle = IOracle(0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419);
        uint256 ethPrice = ethOracle.latestAnswer().div(1e2); // 1e8 div 1e2 = 1e6
        uint256 crvPrice = crveth.price_oracle().mul(ethPrice).div(1e18); // 1e18 mul 1e6 div 1e18 = 1e6
        uint256 cvxPrice = cvxeth.price_oracle().mul(ethPrice).div(1e18); // 1e18 mul 1e6 div 1e18 = 1e6

        uint256 crvValue = crvPrice.mul(_claimableBal).div(1e18); // 1e6 mul 1e18 div 1e18 = 1e6
        uint256 cvxValue = cvxPrice.mul(mintableCvx).div(1e18); // 1e6 mul 1e18 div 1e18 = 1e6

        // get the value of our rewards token if we have one
        uint256 rewardsValue;
        if (hasRewards) {
            address[] memory usd_path = new address[](3);
            usd_path[0] = address(rewardsToken);
            usd_path[1] = address(weth);
            usd_path[2] = address(usdt);

            uint256 _claimableBonusBal =
                IConvexRewards(virtualRewardsPool).earned(address(this));
            if (_claimableBonusBal > 0) {
                uint256[] memory rewardSwap =
                    IUniswapV2Router02(router).getAmountsOut(
                        _claimableBonusBal,
                        usd_path
                    );
                rewardsValue = rewardSwap[rewardSwap.length - 1];
            }
        }

        return crvValue.add(cvxValue).add(rewardsValue);
    }

    // convert our keeper's eth cost into want, we don't need this anymore since we don't use baseStrategy harvestTrigger
    function ethToWant(uint256 _ethAmount)

        public

        view

        override

        returns (uint256)

    {}

    // check if the current baseFee is below our external target
    function isBaseFeeAcceptable() internal view returns (bool) {
        return
            IBaseFee(0xb5e1CAcB567d98faaDB60a1fD4820720141f064F)
                .isCurrentBaseFeeAcceptable();
    }

    /// @notice True if someone needs to earmark rewards on Convex before keepers harvest again
    function needsEarmarkReward() public view returns (bool needsEarmark) {
        // check if there is any CRV we need to earmark
        uint256 crvExpiry = rewardsContract.periodFinish();
        if (crvExpiry < block.timestamp) {
            return true;
        } else if (hasRewards) {
            // check if there is any bonus reward we need to earmark
            uint256 rewardsExpiry =
                IConvexRewards(virtualRewardsPool).periodFinish();
            return rewardsExpiry < block.timestamp;
        }
    }

    /* ========== SETTERS ========== */

    // These functions are useful for setting parameters of the strategy that may need to be adjusted.

    /// @notice Use to add, update or remove rewards.
    function updateRewards(

        bool _hasRewards,

        uint256 _rewardsIndex,

        bool useSushi

    ) external onlyGovernance {
        if (
            address(rewardsToken) != address(0) &&
            address(rewardsToken) != address(convexToken)
        ) {
            rewardsToken.approve(router, uint256(0));
        }
        if (_hasRewards == false) {
            hasRewards = false;
            rewardsToken = IERC20(address(0));
            virtualRewardsPool = address(0);
        } else {
            // update with our new token. get this via our virtualRewardsPool
            virtualRewardsPool = rewardsContract.extraRewards(_rewardsIndex);
            address _rewardsToken =
                IConvexRewards(virtualRewardsPool).rewardToken();
            rewardsToken = IERC20(_rewardsToken);

            // set which router we will be using
            if (useSushi) {
                router = sushiswap;
            } else {
                router = uniswapV2;
            }

            // approve, setup our path, and turn on rewards
            rewardsToken.approve(router, type(uint256).max);
            rewardsPath = [address(rewardsToken), address(weth)];
            hasRewards = true;
        }
    }

    /**

     * @notice

     * Here we set various parameters to optimize our harvestTrigger.

     * @param _harvestProfitMin The amount of profit (in USDC, 6 decimals)

     * that will trigger a harvest if gas price is acceptable.

     * @param _harvestProfitMax The amount of profit in USDC that

     * will trigger a harvest regardless of gas price.

     * @param _creditThreshold The number of want tokens that will

     * automatically trigger a harvest once gas is cheap enough.

     * @param _checkEarmark Whether or not we should check Convex's

     * booster to see if we need to earmark before harvesting.

     */
    function setHarvestTriggerParams(

        uint256 _harvestProfitMin,

        uint256 _harvestProfitMax,

        uint256 _creditThreshold,

        bool _checkEarmark

    ) external onlyVaultManagers {
        harvestProfitMin = _harvestProfitMin;
        harvestProfitMax = _harvestProfitMax;
        creditThreshold = _creditThreshold;
        checkEarmark = _checkEarmark;
    }

    /// @notice Set the fee pool we'd like to swap through on UniV3 (1% = 10_000)
    function setUniFees(uint24 _wbtcFee) external onlyVaultManagers {
        uniWbtcFee = _wbtcFee;
    }
}