// File: src/Strategy.sol



// SPDX-License-Identifier: MIT

pragma experimental ABIEncoderV2;
pragma solidity ^0.8.12;

import "@openzeppelin/contracts/utils/math/Math.sol";
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {Address} from "@openzeppelin/contracts/utils/Address.sol";

import {
    BaseStrategy,
    StrategyParams
} from "@yearnvaults/contracts/BaseStrategy.sol";
import {IERC20Metadata} from "@yearnvaults/contracts/yToken.sol";

import "./interfaces/Angle/IStableMaster.sol";
import "./interfaces/Angle/IAngleGauge.sol";
import "./interfaces/Yearn/ITradeFactory.sol";
import "./interfaces/Uniswap/IUniV2.sol";
import {AngleStrategyVoterProxy} from "./AngleStrategyVoterProxy.sol";


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

contract Strategy is BaseStrategy {
    using SafeERC20 for IERC20;
    using Address for address;

    event Cloned(address indexed clone);

    bool public isOriginal = true;

    IERC20 public constant angleToken = IERC20(0x31429d1856aD1377A8A0079410B297e1a9e214c2);
    IStableMaster public constant angleStableMaster = IStableMaster(0x5adDc89785D75C86aB939E9e15bfBBb7Fc086A87);
    AngleStrategyVoterProxy public strategyProxy;

    uint256 public constant MAX_BPS = 10000;

    // variable for determining how much governance token to hold for voting rights
    uint256 public percentKeep;
    IERC20 public sanToken;
    IAngleGauge public sanTokenGauge;
    address public constant treasury = 0x93A62dA5a14C80f265DAbC077fCEE437B1a0Efde; // To change this, migrate
    address public constant unirouter = 0xd9e1cE17f2641f24aE83637ab66a2cca9C378B9F; // SushiSwap
    address public constant usdt = 0xdAC17F958D2ee523a2206206994597C13D831ec7;
    address public constant weth = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    address public poolManager;
    address public tradeFactory = address(0);

    // 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

    constructor(
        address _vault,
        address _sanToken,
        address _sanTokenGauge,
        address _poolManager,
        address _strategyProxy
    ) public BaseStrategy(_vault) {
        // Constructor should initialize local variables
        _initializeStrategy(
            _sanToken,
            _sanTokenGauge,
            _poolManager,
            _strategyProxy
        );
    }

    // Cloning & initialization code adapted from https://github.com/yearn/yearn-vaults/blob/43a0673ab89742388369bc0c9d1f321aa7ea73f6/contracts/BaseStrategy.sol#L866

    function _initializeStrategy(
        address _sanToken,
        address _sanTokenGauge,
        address _poolManager,
        address _strategyProxy
    ) internal {
        sanToken = IERC20(_sanToken);
        sanTokenGauge = IAngleGauge(_sanTokenGauge);
        poolManager = _poolManager;
        strategyProxy = AngleStrategyVoterProxy(_strategyProxy);

        percentKeep = 1000;
        healthCheck = 0xDDCea799fF1699e98EDF118e0629A974Df7DF012;
        doHealthCheck = true;

        maxReportDelay = 21 days; // 21 days in seconds, if we hit this then harvestTrigger = True
        harvestProfitMin = 2_000e6;
        harvestProfitMax = 10_000e6;
        creditThreshold = 1e6 * 1e18;
        
    }

    function initialize(
        address _vault,
        address _strategist,
        address _rewards,
        address _keeper,
        address _sanToken,
        address _sanTokenGauge,
        address _poolManager,
        address _strategyProxy
    ) external {
        _initialize(_vault, _strategist, _rewards, _keeper);
        _initializeStrategy(
            _sanToken,
            _sanTokenGauge,
            _poolManager,
            _strategyProxy
        );
    }

    function cloneAngle(
        address _vault,
        address _strategist,
        address _rewards,
        address _keeper,
        address _sanToken,
        address _sanTokenGauge,
        address _poolManager,
        address _strategyProxy
    ) external returns (address newStrategy) {
        require(isOriginal, "!clone");
        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)
        }

        Strategy(newStrategy).initialize(
            _vault,
            _strategist,
            _rewards,
            _keeper,
            _sanToken,
            _sanTokenGauge,
            _poolManager,
            _strategyProxy
        );

        emit Cloned(newStrategy);
    }

    function name() external view override returns (string memory) {
        return
            string(
                abi.encodePacked(
                    "StrategyAngle",
                    IERC20Metadata(address(want)).symbol()
                )
            );
    }

    // returns sum of all assets, realized and unrealized
    function estimatedTotalAssets() public view override returns (uint256) {
        return balanceOfWant() + valueOfStakedSanToken() + valueOfSanToken();
    }

    function prepareReturn(uint256 _debtOutstanding)
        internal
        override
        returns (
            uint256 _profit,
            uint256 _loss,
            uint256 _debtPayment
        )
    {
        // Run initial profit + loss calculations.

        uint256 _totalAssets = estimatedTotalAssets();
        uint256 _totalDebt = vault.strategies(address(this)).totalDebt;

        if (_totalAssets >= _totalDebt) {
            // Implicitly, _profit & _loss are 0 before we change them.
            _profit = _totalAssets - _totalDebt;
        } else {
            _loss = _totalDebt - _totalAssets;
        }

        // Free up _debtOutstanding + our profit, and make any necessary adjustments to the accounting.

        (uint256 _amountFreed, uint256 _liquidationLoss) =
            liquidatePosition(_debtOutstanding + _profit);

        _loss = _loss + _liquidationLoss;

        _debtPayment = Math.min(_debtOutstanding, _amountFreed);

        if (_loss > _profit) {
            _loss = _loss - _profit;
            _profit = 0;
        } else {
            _profit = _profit - _loss;
            _loss = 0;
        }

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

    // Deposit value & stake
    function adjustPosition(uint256 _debtOutstanding) internal override {
        if (emergencyExit) {
            return;
        }

        // Claim rewards here so that we can chain tend() -> yswap sell -> harvest() in a single transaction
        strategyProxy.claimRewards(address(sanTokenGauge));

        uint256 _tokensAvailable = balanceOfAngleToken();
        if (_tokensAvailable > 0) {
            uint256 _tokensToKeep =
                (_tokensAvailable * percentKeep) / MAX_BPS;
            if (_tokensToKeep > 0) {
                IERC20(angleToken).transfer(address(strategyProxy.yearnAngleVoter()), _tokensToKeep);
            }
        }

        uint256 _balanceOfWant = balanceOfWant();

        // do not invest if we have more debt than want
        if (_debtOutstanding > _balanceOfWant) {
            return;
        }

        // Invest the rest of the want
        uint256 _wantAvailable = _balanceOfWant - _debtOutstanding;
        if (_wantAvailable > 0) {
            // deposit for sanToken
            want.safeTransfer(address(strategyProxy), _wantAvailable);
            depositToStableMaster(_wantAvailable);
        }

        // Stake any san tokens, whether they originated through the above deposit or some other means (e.g. migration)
        uint256 _sanTokenBalance = balanceOfSanToken();
        if (_sanTokenBalance > 0) {
            strategyProxy.stake(address(sanTokenGauge), _sanTokenBalance, address(sanToken));
        }
    }

    function liquidateAllPositions()
        internal
        override
        returns (uint256 _amountFreed)
    {
        (_amountFreed, ) = liquidatePosition(estimatedTotalAssets());
    }

    function liquidatePosition(uint256 _amountNeeded)
        internal
        override
        returns (uint256 _liquidatedAmount, uint256 _loss)
    {
        // NOTE: Maintain invariant `_liquidatedAmount + _loss <= _amountNeeded`
        _amountNeeded = Math.min(_amountNeeded, estimatedTotalAssets()); // This makes it safe to request to liquidate more than we have

        uint256 _balanceOfWant = balanceOfWant();
        if (_balanceOfWant < _amountNeeded) {
            // We need to withdraw to get back more want
            _withdrawSome(_amountNeeded - _balanceOfWant);
            // reload balance of want after side effect
            _balanceOfWant = balanceOfWant();
        }

        if (_balanceOfWant >= _amountNeeded) {
            _liquidatedAmount = _amountNeeded;
        } else {
            _liquidatedAmount = _balanceOfWant;
            _loss = _amountNeeded - _balanceOfWant;
        }
    }

    // withdraw some want from Angle
    function _withdrawSome(uint256 _amount) internal {
        uint256 _amountInSanToken = wantToSanToken(_amount);

        uint256 _sanTokenBalance = balanceOfSanToken();
        if (_amountInSanToken > _sanTokenBalance) {
            _amountInSanToken = Math.min(_amountInSanToken - _sanTokenBalance, balanceOfStakedSanToken());
            strategyProxy.withdraw(
                address(sanTokenGauge),
                address(sanToken),
                _amountInSanToken
            );
            IERC20(sanToken).safeTransfer(address(strategyProxy), _amountInSanToken);
        }

        withdrawFromStableMaster(_amountInSanToken);
    }

    // can be used in conjunction with migration if this function is still working
    function claimRewards() external onlyVaultManagers {
        strategyProxy.claimRewards(address(sanTokenGauge));
    }

    // transfers all tokens to new strategy
    function prepareMigration(address _newStrategy) internal override {
        // Claim rewards is called externally + sweep by governance
        // Governance can then revoke this strategy and approve the new one so the 
        // funds assigned to this gauge in the proxy are available
    }

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


    function ethToWant(uint256 _amtInWei)
        public
        view
        override
        returns (uint256)
    {
        return _amtInWei;
    }

    /* ========== 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;
        }

        // 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 - 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) {
        address[] memory path = new address[](3);
        path[0] = address(angleToken);
        path[1] = weth;
        path[2] = address(usdt);

        uint256 _claimableRewards = sanTokenGauge.claimable_reward(address(this), address(angleToken));

        if (_claimableRewards < 1e18) { // Dust check
            return 0;
        }

        uint256[] memory amounts = IUniV2(unirouter).getAmountsOut(
            _claimableRewards,
            path
        );

        return amounts[amounts.length - 1];
    }

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


    // ---------------------- SETTERS -----------------------

    // This allows us to manually harvest with our keeper as needed
    function setForceHarvestTriggerOnce(bool _forceHarvestTriggerOnce)
        external
        onlyVaultManagers
    {
        forceHarvestTriggerOnce = _forceHarvestTriggerOnce;
    }

    // Min profit to start checking for harvests if gas is good, max will harvest no matter gas (both in USDT, 6 decimals). Credit threshold is in want token, and will trigger a harvest if credit is large enough. check earmark to look at convex's booster.
    function setHarvestTriggerParams(
        uint256 _harvestProfitMin,
        uint256 _harvestProfitMax,
        uint256 _creditThreshold
    ) external onlyVaultManagers {
        harvestProfitMin = _harvestProfitMin;
        harvestProfitMax = _harvestProfitMax;
        creditThreshold = _creditThreshold;
    }

    function setKeepInBips(uint256 _percentKeep) external onlyVaultManagers {
        require(
            _percentKeep <= MAX_BPS,
            "_percentKeep can't be larger than 10,000"
        );
        percentKeep = _percentKeep;
    }

    // ----------------- SUPPORT & UTILITY FUNCTIONS ----------

    function balanceOfWant() public view returns (uint256) {
        return want.balanceOf(address(this));
    }

    function balanceOfStakedSanToken() public view returns (uint256) {
        return strategyProxy.balanceOfStakedSanToken(address(sanTokenGauge));
    }

    function balanceOfSanToken() public view returns (uint256) {
        return strategyProxy.balanceOfSanToken(address(sanToken));
    }

    function balanceOfAngleToken() public view returns (uint256) {
        return angleToken.balanceOf(address(this));
    }

    function valueOfSanToken() public view returns (uint256) {
        return sanTokenToWant(balanceOfSanToken());
    }

    function valueOfStakedSanToken() public view returns (uint256) {
        return sanTokenToWant(balanceOfStakedSanToken());
    }

    function sanTokenToWant(uint256 _sanTokenAmount)
        public
        view
        returns (uint256)
    {
        return (_sanTokenAmount * getSanRate()) / 1e18;
    }

    function wantToSanToken(uint256 _wantAmount) public view returns (uint256) {
        return ((_wantAmount * 1e18) / getSanRate()) + 1;
    }

    // Get rate of conversion between sanTokens and want
    function getSanRate() public view returns (uint256) {
        (, , , , , uint256 _sanRate, , , ) =
            IStableMaster(angleStableMaster).collateralMap(poolManager);

        return _sanRate;
    }

    function depositToStableMaster(uint256 _amount) internal {
        strategyProxy.depositToStableMaster(
            address(angleStableMaster),
            _amount,
            poolManager,
            address(want),
            address(sanTokenGauge)
        );
    }

    function withdrawFromStableMaster(uint256 _amountInSanToken) internal {
        strategyProxy.withdrawFromStableMaster(
            address(angleStableMaster),
            _amountInSanToken,
            poolManager,
            address(sanToken),
            address(sanTokenGauge)
        );
    }

    // ---------------------- YSWAPS FUNCTIONS ----------------------

    function setTradeFactory(address _tradeFactory) external onlyGovernance {
        if (tradeFactory != address(0)) {
            _removeTradeFactoryPermissions();
        }
        angleToken.safeApprove(_tradeFactory, type(uint256).max);
        ITradeFactory tf = ITradeFactory(_tradeFactory);
        tf.enable(address(angleToken), address(want));
        tradeFactory = _tradeFactory;
    }

    function removeTradeFactoryPermissions() external onlyEmergencyAuthorized {
        _removeTradeFactoryPermissions();
    }

    function _removeTradeFactoryPermissions() internal {
        angleToken.safeApprove(tradeFactory, 0);
        tradeFactory = address(0);
    }
}

// File: lib/openzeppelin-contracts/contracts/utils/math/Math.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @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.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a / b + (a % b == 0 ? 0 : 1);
    }
}

// File: lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using Address for address;

    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 value
    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 newAllowance = token.allowance(address(this), spender) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) {
            // Return data is optional
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: lib/openzeppelin-contracts/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Address.sol)

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: lib/yearn-vaults/contracts/BaseStrategy.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.12;
pragma experimental ABIEncoderV2;

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {ERC20} from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.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 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) {
        _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, type(uint256).max); // 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, type(uint256).max); // 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, type(uint256).max);
        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 - params.lastReport < minReportDelay) return false;

        // Should trigger if hasn't been called in a while
        if (block.timestamp - 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 + debtThreshold < params.totalDebt) return true;

        uint256 profit = 0;
        if (total > params.totalDebt) profit = total - 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 * callCost < credit + 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 - amountFreed;
            } else if (amountFreed > debtOutstanding) {
                profit = amountFreed - debtOutstanding;
            }
            debtPayment = debtOutstanding - 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 {
            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) 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: lib/yearn-vaults/contracts/yToken.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity >=0.8.0 <0.9.0;
pragma experimental ABIEncoderV2;

import {Address} from "@openzeppelin/contracts/utils/Address.sol";
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";

import {VaultAPI, BaseWrapper} from "./BaseWrapper.sol";

interface IERC20Metadata {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

contract yToken is IERC20, BaseWrapper {
    mapping(address => mapping(address => uint256)) public override allowance;

    constructor(address _token, address _registry) BaseWrapper(_token, _registry) {}

    function name() external view returns (string memory) {
        return string(abi.encodePacked("Yearn ", IERC20Metadata(address(token)).name()));
    }

    function symbol() external view returns (string memory) {
        return string(abi.encodePacked("y", IERC20Metadata(address(token)).symbol()));
    }

    function decimals() external view returns (uint256) {
        return IERC20Metadata(address(token)).decimals();
    }

    function totalSupply() external view override returns (uint256 total) {
        return totalAssets();
    }

    function balanceOf(address account) external view override returns (uint256 balance) {
        return totalVaultBalance(account);
    }

    function _transfer(
        address sender,
        address receiver,
        uint256 amount
    ) internal {
        require(receiver != address(0), "ERC20: transfer to the zero address");
        require(amount == _withdraw(sender, receiver, amount, true)); // `true` means use `bestVault`
        emit Transfer(sender, receiver, amount);
    }

    function transfer(address receiver, uint256 amount) public virtual override returns (bool) {
        _transfer(msg.sender, receiver, amount);
        return true;
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        allowance[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    function approve(address spender, uint256 amount) public override returns (bool) {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address receiver,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(sender, receiver, amount);
        _approve(sender, msg.sender, allowance[sender][msg.sender] - amount);
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(msg.sender, spender, allowance[msg.sender][spender] + addedValue);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(msg.sender, spender, allowance[msg.sender][spender] - subtractedValue);
        return true;
    }

    function deposit(uint256 amount) external returns (uint256) {
        return _deposit(msg.sender, msg.sender, amount, true); // `true` = pull from sender
    }

    function withdraw(uint256 amount) external returns (uint256) {
        return _withdraw(msg.sender, msg.sender, amount, true); // `true` = withdraw from `bestVault`
    }

    function _permitAll(
        address user,
        VaultAPI[] calldata vaults,
        bytes[] calldata signatures
    ) internal {
        require(vaults.length == signatures.length);
        for (uint256 i = 0; i < vaults.length; i++) {
            require(vaults[i].permit(user, address(this), type(uint256).max, 0, signatures[i]));
        }
    }

    function permitAll(VaultAPI[] calldata vaults, bytes[] calldata signatures) public {
        _permitAll(msg.sender, vaults, signatures);
    }

    function migrate() external returns (uint256) {
        return _migrate(msg.sender);
    }

    function migrate(uint256 amount) external returns (uint256) {
        return _migrate(msg.sender, amount);
    }

    function migrate(uint256 amount, uint256 maxMigrationLoss) external returns (uint256) {
        return _migrate(msg.sender, amount, maxMigrationLoss);
    }

    function migrate(VaultAPI[] calldata vaults, bytes[] calldata signatures) external returns (uint256) {
        _permitAll(msg.sender, vaults, signatures);
        return _migrate(msg.sender);
    }

    function migrate(
        VaultAPI[] calldata vaults,
        bytes[] calldata signatures,
        uint256 amount
    ) external returns (uint256) {
        _permitAll(msg.sender, vaults, signatures);
        return _migrate(msg.sender, amount);
    }

    function migrate(
        VaultAPI[] calldata vaults,
        bytes[] calldata signatures,
        address user,
        uint256 amount
    ) external returns (uint256) {
        _permitAll(user, vaults, signatures);
        return _migrate(user, amount);
    }

    function revokeAll(VaultAPI[] calldata vaults, bytes[] calldata signatures) external {
        require(vaults.length == signatures.length);
        for (uint256 i = 0; i < vaults.length; i++) {
            require(vaults[i].permit(msg.sender, address(this), 0, 0, signatures[i]));
        }
    }
}

interface IWETH {
    function deposit() external payable;

    function withdraw(uint256 wad) external;
}

contract yWETH is ReentrancyGuard, yToken {
    using Address for address payable;

    constructor(address _weth, address _registry) yToken(_weth, _registry) {}

    function depositETH() public payable returns (uint256) {
        uint256 amount = msg.value;
        // NOTE: `BaseWrapper.token` is WETH
        IWETH(address(token)).deposit{value: amount}();
        // NOTE: Deposit handles approvals
        // NOTE: Need to use different method to deposit than `yToken`
        return _deposit(address(this), msg.sender, amount, false); // `false` = pull from `this`
    }

    function withdrawETH(uint256 amount) external nonReentrant returns (uint256 withdrawn) {
        // NOTE: Need to use different method to withdraw than `yToken`
        withdrawn = _withdraw(msg.sender, address(this), amount, true); // `true` = withdraw from `bestVault`
        // NOTE: `BaseWrapper.token` is WETH
        IWETH(address(token)).withdraw(withdrawn);
        // NOTE: Any unintentionally
        payable(msg.sender).sendValue(address(this).balance);
    }

    receive() external payable {
        if (msg.sender != address(token)) {
            depositETH();
        } // else: WETH is sending us back ETH, so don't do anything (to avoid recursion)
    }
}

// File: src/interfaces/Angle/IStableMaster.sol



// SPDX-License-Identifier: GPL-3.0

pragma experimental ABIEncoderV2;
pragma solidity ^0.8.12;

// Struct to handle all the parameters to manage the fees
// related to a given collateral pool (associated to the stablecoin)
struct MintBurnData {
    // Values of the thresholds to compute the minting fees
    // depending on HA hedge (scaled by `BASE_PARAMS`)
    uint64[] xFeeMint;
    // Values of the fees at thresholds (scaled by `BASE_PARAMS`)
    uint64[] yFeeMint;
    // Values of the thresholds to compute the burning fees
    // depending on HA hedge (scaled by `BASE_PARAMS`)
    uint64[] xFeeBurn;
    // Values of the fees at thresholds (scaled by `BASE_PARAMS`)
    uint64[] yFeeBurn;
    // Max proportion of collateral from users that can be covered by HAs
    // It is exactly the same as the parameter of the same name in `PerpetualManager`, whenever one is updated
    // the other changes accordingly
    uint64 targetHAHedge;
    // Minting fees correction set by the `FeeManager` contract: they are going to be multiplied
    // to the value of the fees computed using the hedge curve
    // Scaled by `BASE_PARAMS`
    uint64 bonusMalusMint;
    // Burning fees correction set by the `FeeManager` contract: they are going to be multiplied
    // to the value of the fees computed using the hedge curve
    // Scaled by `BASE_PARAMS`
    uint64 bonusMalusBurn;
    // Parameter used to limit the number of stablecoins that can be issued using the concerned collateral
    uint256 capOnStableMinted;
}

// Struct to handle all the variables and parameters to handle SLPs in the protocol
// including the fraction of interests they receive or the fees to be distributed to
// them
struct SLPData {
    // Last timestamp at which the `sanRate` has been updated for SLPs
    uint256 lastBlockUpdated;
    // Fees accumulated from previous blocks and to be distributed to SLPs
    uint256 lockedInterests;
    // Max interests used to update the `sanRate` in a single block
    // Should be in collateral token base
    uint256 maxInterestsDistributed;
    // Amount of fees left aside for SLPs and that will be distributed
    // when the protocol is collateralized back again
    uint256 feesAside;
    // Part of the fees normally going to SLPs that is left aside
    // before the protocol is collateralized back again (depends on collateral ratio)
    // Updated by keepers and scaled by `BASE_PARAMS`
    uint64 slippageFee;
    // Portion of the fees from users minting and burning
    // that goes to SLPs (the rest goes to surplus)
    uint64 feesForSLPs;
    // Slippage factor that's applied to SLPs exiting (depends on collateral ratio)
    // If `slippage = BASE_PARAMS`, SLPs can get nothing, if `slippage = 0` they get their full claim
    // Updated by keepers and scaled by `BASE_PARAMS`
    uint64 slippage;
    // Portion of the interests from lending
    // that goes to SLPs (the rest goes to surplus)
    uint64 interestsForSLPs;
}

/// @title IStableMasterFunctions
/// @author Angle Core Team
/// @notice Interface for the `StableMaster` contract
interface IStableMasterFunctions {
    // ============================== Lending ======================================

    function accumulateInterest(uint256 gain) external;

    function signalLoss(uint256 loss) external;

    // ============================== HAs ==========================================

    function getStocksUsers() external view returns (uint256 maxCAmountInStable);

    function convertToSLP(uint256 amount, address user) external;

    // ============================== Keepers ======================================

    function getCollateralRatio() external returns (uint256);

    function setFeeKeeper(
        uint64 feeMint,
        uint64 feeBurn,
        uint64 _slippage,
        uint64 _slippageFee
    ) external;

    // ============================== AgToken ======================================

    function updateStocksUsers(uint256 amount, address poolManager) external;
}

/// @title IStableMaster
/// @author Angle Core Team
/// @notice Previous interface with additionnal getters for public variables and mappings
interface IStableMaster is IStableMasterFunctions {
    function agToken() external view returns (address);

    function collateralMap(address poolManager)
        external
        view
        returns (
            address token,
            address sanToken,
            address perpetualManager,
            address oracle,
            uint256 stocksUsers,
            uint256 sanRate,
            uint256 collatBase,
            SLPData memory slpData,
            MintBurnData memory feeData
        );

    /// @notice Lets a SLP enter the protocol by sending collateral to the system in exchange of sanTokens
    /// @param user Address of the SLP to send sanTokens to
    /// @param amount Amount of collateral sent
    /// @param poolManager Address of the `PoolManager` of the required collateral
    function deposit(
        uint256 amount,
        address user,
        address poolManager
    ) external;

    /// @notice Lets a SLP burn of sanTokens and receive the corresponding collateral back in exchange at the
    /// current exchange rate between sanTokens and collateral
    /// @param amount Amount of sanTokens burnt by the SLP
    /// @param burner Address that will burn its sanTokens
    /// @param dest Address that will receive the collateral
    /// @param poolManager Address of the `PoolManager` of the required collateral
    /// @dev The `msg.sender` should have approval to burn from the `burner` or the `msg.sender` should be the `burner`
    /// @dev This transaction will fail if the `PoolManager` does not have enough reserves, the front will however be here
    /// to notify them that they cannot withdraw
    /// @dev In case there are not enough reserves, strategies should be harvested or their debt ratios should be adjusted
    /// by governance to make sure that users, HAs or SLPs withdrawing always have free collateral they can use
    function withdraw(
        uint256 amount,
        address burner,
        address dest,
        address poolManager
    ) external;
}
// File: src/interfaces/Angle/IAngleGauge.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.12;

interface IAngleGauge {

    //it stakes.
    function deposit(uint256 amount) external;

    //gimme profit
    function claim_rewards() external;

    //gimme principal
    function withdraw(uint256 amount) external;

    //getReward and Withdraw in same go
    function exit() external;

    //basically a sweep in case things get weird
    function recoverERC20(address tokenAddress, address to, uint256 amount) external;

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

    function claimable_reward(address _user, address _reward_token) external view returns (uint256);

}


// File: src/interfaces/Yearn/ITradeFactory.sol



// SPDX-License-Identifier: AGPL-3.0

pragma solidity ^0.8.12;

struct AsyncTradeExecutionDetails {
    address _strategy;
    address _tokenIn;
    address _tokenOut;
    uint256 _amount;
    uint256 _minAmountOut;
}

interface ITradeFactory {
    function enable(address rewards, address want) external;

    function grantRole(bytes32 role, address account) external;

    function STRATEGY() external view returns (bytes32);

    function execute(
        AsyncTradeExecutionDetails calldata _tradeExecutionDetails,
        address _swapper,
        bytes calldata _data
  ) external returns (uint256 _receivedAmount);
}
// File: src/interfaces/Uniswap/IUniV2.sol



// SPDX-License-Identifier: MIT
pragma solidity ^0.8.12;

interface IUniV2 {
    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function swapExactTokensForTokens(
        uint256,
        uint256,
        address[] calldata,
        address,
        uint256
    ) external;

    function getAmountsOut(uint256 amountIn, address[] memory path)
        external
        view
        returns (uint256[] memory amounts);

}

// File: src/AngleStrategyVoterProxy.sol



// SPDX-License-Identifier: AGPL-3.0
pragma solidity ^0.8.12;
pragma experimental ABIEncoderV2;

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {Address} from "@openzeppelin/contracts/utils/Address.sol";

import {YearnAngleVoter} from "./YearnAngleVoter.sol";

import "./interfaces/curve/ICurve.sol";
import "./interfaces/Angle/IStableMaster.sol";
import "./interfaces/Angle/IAngleGauge.sol";
import "./interfaces/Uniswap/IUniV2.sol";

library SafeVoter {
    function safeExecute(
        YearnAngleVoter voter,
        address to,
        uint256 value,
        bytes memory data
    ) internal {
        (bool success, bytes memory result) = voter.execute(to, value, data);
        require(success, string(result));
    }
}

contract AngleStrategyVoterProxy {
    using SafeVoter for YearnAngleVoter;
    using SafeERC20 for IERC20;
    using Address for address;

    YearnAngleVoter public yearnAngleVoter;
    address public constant angleToken = address(0x31429d1856aD1377A8A0079410B297e1a9e214c2);

    uint256 public constant UNLOCK_TIME = 4 * 365 * 24 * 60 * 60;

    // gauge => strategies
    mapping(address => address) public strategies;
    mapping(address => bool) public voters;
    address public governance;

    constructor(address _voter) public {
        governance = address(0xFEB4acf3df3cDEA7399794D0869ef76A6EfAff52);
        yearnAngleVoter = YearnAngleVoter(_voter);
    }

    function setGovernance(address _governance) external {
        require(msg.sender == governance, "!governance");
        governance = _governance;
    }

    function approveStrategy(address _gauge, address _strategy) external {
        require(msg.sender == governance, "!governance");
        strategies[_gauge] = _strategy;
    }

    function revokeStrategy(address _gauge) external {
        require(msg.sender == governance, "!governance");
        strategies[_gauge] = address(0);
    }

    function approveVoter(address _voter) external {
        require(msg.sender == governance, "!governance");
        voters[_voter] = true;
    }

    function revokeVoter(address _voter) external {
        require(msg.sender == governance, "!governance");
        voters[_voter] = false;
    }

    function lock(uint256 amount) external {
        if (amount > 0 && amount <= IERC20(angleToken).balanceOf(address(yearnAngleVoter))) {
            yearnAngleVoter.createLock(amount, block.timestamp + UNLOCK_TIME);
        }
    }

    function increaseAmount(uint256 amount) external {
        if (amount > 0 && amount <= IERC20(angleToken).balanceOf(address(yearnAngleVoter))) {
            yearnAngleVoter.increaseAmount(amount);
        }
    }

    function vote(address _gauge, uint256 _amount) public {
        require(voters[msg.sender], "!voter");
        yearnAngleVoter.safeExecute(_gauge, 0, abi.encodeWithSignature("vote_for_gauge_weights(address,uint256)", _gauge, _amount));
    }

    function withdraw(
        address _gauge,
        address _token,
        uint256 _amount
    ) public returns (uint256) {
        require(strategies[_gauge] == msg.sender, "!strategy");
        uint256 _balance = IERC20(_token).balanceOf(address(yearnAngleVoter));
        yearnAngleVoter.safeExecute(_gauge, 0, abi.encodeWithSignature("withdraw(uint256)", _amount));
        _balance = IERC20(_token).balanceOf(address(yearnAngleVoter)) - _balance;
        yearnAngleVoter.safeExecute(_token, 0, abi.encodeWithSignature("transfer(address,uint256)", msg.sender, _balance));
        return _balance;
    }

    function withdrawFromStableMaster(address stableMaster, uint256 amount, 
        address poolManager, address token, address gauge) external {
        require(strategies[gauge] == msg.sender, "!strategy");

        IERC20(token).safeTransfer(address(yearnAngleVoter), amount);

        yearnAngleVoter.safeExecute(stableMaster, 0, abi.encodeWithSignature(
            "withdraw(uint256,address,address,address)", 
            amount,
            address(yearnAngleVoter),
            msg.sender,
            poolManager
            ));
    }

    function balanceOfStakedSanToken(address _gauge) public view returns (uint256) {
        return IERC20(_gauge).balanceOf(address(yearnAngleVoter));
    }

    function withdrawAll(address _gauge, address _token) external returns (uint256) {
        require(strategies[_gauge] == msg.sender, "!strategy");
        return withdraw(_gauge, _token, balanceOfStakedSanToken(_gauge));
    }

    function stake(address gauge, uint256 amount, address token) external {
        require(strategies[gauge] == msg.sender, "!strategy");

        _checkAllowance(token, gauge, amount);

        yearnAngleVoter.safeExecute(gauge, 0, abi.encodeWithSignature(
            "deposit(uint256)", 
            amount
            ));
    }

    function depositToStableMaster(address stableMaster, uint256 amount, 
        address poolManager, address token, address gauge) external {
        require(strategies[gauge] == msg.sender, "!strategy");
        
        IERC20(token).safeTransfer(address(yearnAngleVoter), amount);

        _checkAllowance(token, stableMaster, amount);

        yearnAngleVoter.safeExecute(stableMaster, 0, abi.encodeWithSignature(
            "deposit(uint256,address,address)", 
            amount,
            address(yearnAngleVoter),
            poolManager
            ));
    }

    function claimRewards(address _gauge) external {
        require(strategies[_gauge] == msg.sender, "!strategy");
        yearnAngleVoter.safeExecute(
            _gauge, 
            0, 
            abi.encodeWithSelector(
                IAngleGauge.claim_rewards.selector
            )
        );
        address _token = address(angleToken);
        yearnAngleVoter.safeExecute(_token, 0, abi.encodeWithSignature("transfer(address,uint256)", msg.sender, IERC20(_token).balanceOf(address(yearnAngleVoter))));
    }

    function balanceOfSanToken(address sanToken) public view returns (uint256) {
        return IERC20(sanToken).balanceOf(address(yearnAngleVoter));
    }

    function _checkAllowance(
        address _token,
        address _contract,
        uint256 _amount
    ) internal {
        if (IERC20(_token).allowance(address(yearnAngleVoter), _contract) < _amount) {
            yearnAngleVoter.safeExecute(_token, 0, abi.encodeWithSignature("approve(address,uint256)", _contract, 0));
            yearnAngleVoter.safeExecute(_token, 0, abi.encodeWithSignature("approve(address,uint256)", _contract, _amount));
        }
    }
}
// File: lib/openzeppelin-contracts/contracts/token/ERC20/ERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * Requirements:
     *
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }

        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `amount` of tokens from `sender` to `recipient`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(
        address sender,
        address recipient,
        uint256 amount
    ) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        uint256 senderBalance = _balances[sender];
        require(senderBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[sender] = senderBalance - amount;
        }
        _balances[recipient] += amount;

        emit Transfer(sender, recipient, amount);

        _afterTokenTransfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
        }
        _totalSupply -= amount;

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

// File: lib/openzeppelin-contracts/contracts/security/ReentrancyGuard.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor() {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// File: lib/yearn-vaults/contracts/BaseWrapper.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.12;
pragma experimental ABIEncoderV2;

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {BaseRouter} from "./BaseRouter.sol";
import {VaultAPI} from "./BaseStrategy.sol";
import {Math} from "@openzeppelin/contracts/utils/math/Math.sol";

/**
 * @title Yearn Base Wrapper
 * @author yearn.finance
 * @notice
 *  BaseWrapper 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 Wrapper.
 *  A good starting point to build a wrapper is https://github.com/yearn/brownie-wrapper-mix
 *
 */
abstract contract BaseWrapper is BaseRouter {
    using Math for uint256;

    IERC20 public token;
    uint256 constant MIGRATE_EVERYTHING = type(uint256).max;
    // VaultsAPI.depositLimit is unlimited
    uint256 constant UNCAPPED_DEPOSITS = type(uint256).max;

    constructor(address _token, address _registry) BaseRouter(_registry) {
        // Recommended to use a token with a `Registry.latestVault(_token) != address(0)`
        token = IERC20(_token);
    }

    /**
     * @notice
     *  Used to get the most recent vault for the token using the registry.
     * @return An instance of a VaultAPI
     */
    function bestVault() public view virtual returns (VaultAPI) {
        return bestVault(address(token));
    }

    /**
     * @notice
     *  Used to get all vaults from the registery for the token
     * @return An array containing instances of VaultAPI
     */
    function allVaults() public view virtual returns (VaultAPI[] memory) {
        return allVaults(address(token));
    }

    /**
     * @notice
     *  Used to get the balance of an account accross all the vaults for a token.
     *  @dev will be used to get the wrapper balance using totalVaultBalance(address(this)).
     *  @param account The address of the account.
     *  @return balance of token for the account accross all the vaults.
     */
    function totalVaultBalance(address account) public view returns (uint256) {
        return totalVaultBalance(address(token), account);
    }

    /**
     * @notice
     *  Used to get the TVL on the underlying vaults.
     *  @return assets the sum of all the assets managed by the underlying vaults.
     */
    function totalAssets() public view returns (uint256) {
        return totalAssets(address(token));
    }

    function _deposit(
        address depositor,
        address receiver,
        uint256 amount, // if `MAX_UINT256`, just deposit everything
        bool pullFunds // If true, funds need to be pulled from `depositor` via `transferFrom`
    ) internal returns (uint256) {
        return _deposit(token, depositor, receiver, amount, pullFunds);
    }

    function _withdraw(
        address sender,
        address receiver,
        uint256 amount, // if `MAX_UINT256`, just withdraw everything
        bool withdrawFromBest // If true, also withdraw from `_bestVault`
    ) internal returns (uint256) {
        return _withdraw(token, sender, receiver, amount, withdrawFromBest);
    }

    function _migrate(address account) internal returns (uint256) {
        return _migrate(account, MIGRATE_EVERYTHING);
    }

    function _migrate(address account, uint256 amount) internal returns (uint256) {
        // NOTE: In practice, it was discovered that <50 was the maximum we've see for this variance
        return _migrate(account, amount, 0);
    }

    function _migrate(
        address account,
        uint256 amount,
        uint256 maxMigrationLoss
    ) internal returns (uint256 migrated) {
        VaultAPI _bestVault = bestVault();

        // NOTE: Only override if we aren't migrating everything
        uint256 _depositLimit = _bestVault.depositLimit();
        uint256 _totalAssets = _bestVault.totalAssets();
        if (_depositLimit <= _totalAssets) return 0; // Nothing to migrate (not a failure)

        uint256 _amount = amount;
        if (_depositLimit < UNCAPPED_DEPOSITS && _amount < WITHDRAW_EVERYTHING) {
            // Can only deposit up to this amount
            uint256 _depositLeft = _depositLimit - _totalAssets;
            if (_amount > _depositLeft) _amount = _depositLeft;
        }

        if (_amount > 0) {
            // NOTE: `false` = don't withdraw from `_bestVault`
            uint256 withdrawn = _withdraw(token, account, address(this), _amount, false);
            if (withdrawn == 0) return 0; // Nothing to migrate (not a failure)

            // NOTE: `false` = don't do `transferFrom` because it's already local
            migrated = _deposit(token, address(this), account, withdrawn, false);
            // NOTE: Due to the precision loss of certain calculations, there is a small inefficency
            //       on how migrations are calculated, and this could lead to a DoS issue. Hence, this
            //       value is made to be configurable to allow the user to specify how much is acceptable
            require((withdrawn - migrated) <= maxMigrationLoss);
        } // else: nothing to migrate! (not a failure)
    }
}

// File: src/YearnAngleVoter.sol



// SPDX-License-Identifier: AGPL-3.0
pragma solidity ^0.8.12;
pragma experimental ABIEncoderV2;

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";

import {IVoteEscrow} from "./interfaces/Angle/IVoteEscrow.sol";

contract YearnAngleVoter {
    using SafeERC20 for IERC20;
    
    address constant public angle = address(0x31429d1856aD1377A8A0079410B297e1a9e214c2);
    
    address constant public veAngle = address(0x0C462Dbb9EC8cD1630f1728B2CFD2769d09f0dd5);
    
    address public governance;
    address public pendingGovernance;
    address public proxy;
    
    constructor() public {
        governance = address(0xFEB4acf3df3cDEA7399794D0869ef76A6EfAff52);
    }
    
    function getName() external pure returns (string memory) {
        return "YearnAngleVoter";
    }
    
    function setProxy(address _proxy) external {
        require(msg.sender == governance, "!governance");
        proxy = _proxy;
    }
    
    function createLock(uint256 _value, uint256 _unlockTime) external {
        require(msg.sender == proxy || msg.sender == governance, "!authorized");
        IERC20(angle).approve(veAngle, _value);
        IVoteEscrow(veAngle).create_lock(_value, _unlockTime);
    }
    
    function increaseAmount(uint _value) external {
        require(msg.sender == proxy || msg.sender == governance, "!authorized");
        IERC20(angle).approve(veAngle, _value);
        IVoteEscrow(veAngle).increase_amount(_value);
    }
    
    function release() external {
        require(msg.sender == proxy || msg.sender == governance, "!authorized");
        IVoteEscrow(veAngle).withdraw();
    }
    
    function setGovernance(address _governance) external {
        require(msg.sender == governance, "!governance");
        pendingGovernance = _governance;
    }

    function acceptGovernance() external {
        require(msg.sender == pendingGovernance, "!pending_governance");
        governance = msg.sender;
        pendingGovernance = address(0);
    }
    
    function execute(address to, uint value, bytes calldata data) external returns (bool, bytes memory) {
        require(msg.sender == proxy || msg.sender == governance, "!governance");
        (bool success, bytes memory result) = to.call{value: value}(data);
        
        return (success, result);
    }
}
// File: src/interfaces/curve/ICurve.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.12;

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

    function add_liquidity(
        // sBTC pool
        uint256[3] calldata amounts,
        uint256 min_mint_amount
    ) external;

    function add_liquidity(
        // bUSD pool
        uint256[4] calldata amounts,
        uint256 min_mint_amount
    ) external;

    function add_liquidity(
        // stETH pool
        uint256[2] calldata amounts,
        uint256 min_mint_amount
    ) external payable;

    function coins(uint256) external returns (address);

    function remove_liquidity_imbalance(uint256[2] calldata amounts, uint256 max_burn_amount) external;

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

    function calc_withdraw_one_coin(uint256 _amount, int128 i) external view returns (uint256);

    function remove_liquidity_one_coin(
        uint256 _token_amount,
        int128 i,
        uint256 min_amount
    ) external;

    function exchange(
        int128 from,
        int128 to,
        uint256 _from_amount,
        uint256 _min_to_amount
    ) external payable;

    function exchange_underlying(
        int128 from,
        int128 to,
        uint256 _from_amount,
        uint256 _min_to_amount
    ) external payable;

    function balances(int128) external view returns (uint256);

    function get_dy(
        int128 from,
        int128 to,
        uint256 _from_amount
    ) external view returns (uint256);

    function calc_token_amount( uint256[2] calldata amounts, bool is_deposit) external view returns (uint256);
}

interface Zap {
    function remove_liquidity_one_coin(
        uint256,
        int128,
        uint256
    ) external;
}
// File: lib/openzeppelin-contracts/contracts/token/ERC20/extensions/IERC20Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// File: lib/openzeppelin-contracts/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: lib/yearn-vaults/contracts/BaseRouter.sol



// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.11;
pragma experimental ABIEncoderV2;

import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {Math} from "@openzeppelin/contracts/utils/math/Math.sol";
import {VaultAPI} from "./BaseStrategy.sol";

interface RegistryAPI {
    function governance() external view returns (address);

    function latestVault(address token) external view returns (address);

    function numVaults(address token) external view returns (uint256);

    function vaults(address token, uint256 deploymentId) external view returns (address);
}

/**
 * @title Yearn Base Router
 * @author yearn.finance
 * @notice
 *  BaseRouter 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 Router.
 *  A good starting point to build a router is https://github.com/yearn/brownie-router-mix
 *
 */
abstract contract BaseRouter {
    using Math for uint256;

    // Reduce number of external calls (SLOADs stay the same)
    mapping(address => VaultAPI[]) private _cachedVaults;

    RegistryAPI public registry;

    // ERC20 Unlimited Approvals (short-circuits VaultAPI.transferFrom)
    uint256 constant UNLIMITED_APPROVAL = type(uint256).max;
    // Sentinal values used to save gas on deposit/withdraw/migrate
    // NOTE: DEPOSIT_EVERYTHING == WITHDRAW_EVERYTHING == MIGRATE_EVERYTHING
    uint256 constant DEPOSIT_EVERYTHING = type(uint256).max;
    uint256 constant WITHDRAW_EVERYTHING = type(uint256).max;

    constructor(address _registry) {
        // Recommended to use `v2.registry.ychad.eth`
        registry = RegistryAPI(_registry);
    }

    /**
     * @notice
     *  Used to update the yearn registry.
     * @param _registry The new _registry address.
     */
    function setRegistry(address _registry) external {
        require(msg.sender == registry.governance());
        // In case you want to override the registry instead of re-deploying
        registry = RegistryAPI(_registry);
        // Make sure there's no change in governance
        // NOTE: Also avoid bricking the router from setting a bad registry
        require(msg.sender == registry.governance());
    }

    /**
     * @notice
     *  Used to get the most revent vault for the token using the registry.
     * @return An instance of a VaultAPI
     */
    function bestVault(address token) public view virtual returns (VaultAPI) {
        return VaultAPI(registry.latestVault(token));
    }

    /**
     * @notice
     *  Used to get all vaults from the registery for the token
     * @return An array containing instances of VaultAPI
     */
    function allVaults(address token) public view virtual returns (VaultAPI[] memory) {
        uint256 cache_length = _cachedVaults[token].length;
        uint256 num_vaults = registry.numVaults(token);

        // Use cached
        if (cache_length == num_vaults) {
            return _cachedVaults[token];
        }

        VaultAPI[] memory vaults = new VaultAPI[](num_vaults);

        for (uint256 vault_id = 0; vault_id < cache_length; vault_id++) {
            vaults[vault_id] = _cachedVaults[token][vault_id];
        }

        for (uint256 vault_id = cache_length; vault_id < num_vaults; vault_id++) {
            vaults[vault_id] = VaultAPI(registry.vaults(token, vault_id));
        }

        return vaults;
    }

    function _updateVaultCache(address token, VaultAPI[] memory vaults) internal {
        // NOTE: even though `registry` is update-able by Yearn, the intended behavior
        //       is that any future upgrades to the registry will replay the version
        //       history so that this cached value does not get out of date.
        if (vaults.length > _cachedVaults[token].length) {
            _cachedVaults[token] = vaults;
        }
    }

    /**
     * @notice
     *  Used to get the balance of an account accross all the vaults for a token.
     *  @dev will be used to get the router balance using totalVaultBalance(address(this)).
     *  @param account The address of the account.
     *  @return balance of token for the account accross all the vaults.
     */
    function totalVaultBalance(address token, address account) public view returns (uint256 balance) {
        VaultAPI[] memory vaults = allVaults(token);

        for (uint256 id = 0; id < vaults.length; id++) {
            balance = balance + ((vaults[id].balanceOf(account) * vaults[id].pricePerShare()) / (10**uint256(vaults[id].decimals())));
        }
    }

    /**
     * @notice
     *  Used to get the TVL on the underlying vaults.
     *  @return assets the sum of all the assets managed by the underlying vaults.
     */
    function totalAssets(address token) public view returns (uint256 assets) {
        VaultAPI[] memory vaults = allVaults(token);

        for (uint256 id = 0; id < vaults.length; id++) {
            assets = assets + vaults[id].totalAssets();
        }
    }

    function _deposit(
        IERC20 token,
        address depositor,
        address receiver,
        uint256 amount, // if `MAX_UINT256`, just deposit everything
        bool pullFunds // If true, funds need to be pulled from `depositor` via `transferFrom`
    ) internal returns (uint256 deposited) {
        VaultAPI _bestVault = bestVault(address(token));

        if (pullFunds) {
            if (amount == DEPOSIT_EVERYTHING) {
                amount = token.balanceOf(depositor);
            }
            SafeERC20.safeTransferFrom(token, depositor, address(this), amount);
        }

        if (token.allowance(address(this), address(_bestVault)) < amount) {
            SafeERC20.safeApprove(token, address(_bestVault), 0); // Avoid issues with some tokens requiring 0
            SafeERC20.safeApprove(token, address(_bestVault), UNLIMITED_APPROVAL); // Vaults are trusted
        }

        // Depositing returns number of shares deposited
        // NOTE: Shortcut here is assuming the number of tokens deposited is equal to the
        //       number of shares credited, which helps avoid an occasional multiplication
        //       overflow if trying to adjust the number of shares by the share price.
        uint256 beforeBal = token.balanceOf(address(this));
        if (receiver != address(this)) {
            _bestVault.deposit(amount, receiver);
        } else if (amount != DEPOSIT_EVERYTHING) {
            _bestVault.deposit(amount);
        } else {
            _bestVault.deposit();
        }

        uint256 afterBal = token.balanceOf(address(this));
        deposited = beforeBal - afterBal;
        // `receiver` now has shares of `_bestVault` as balance, converted to `token` here
        // Issue a refund if not everything was deposited
        if (depositor != address(this) && afterBal > 0) SafeERC20.safeTransfer(token, depositor, afterBal);
    }

    function _withdraw(
        IERC20 token,
        address sender,
        address receiver,
        uint256 amount, // if `MAX_UINT256`, just withdraw everything
        bool withdrawFromBest // If true, also withdraw from `_bestVault`
    ) internal returns (uint256 withdrawn) {
        VaultAPI _bestVault = bestVault(address(token));

        VaultAPI[] memory vaults = allVaults(address(token));
        _updateVaultCache(address(token), vaults);

        // NOTE: This loop will attempt to withdraw from each Vault in `allVaults` that `sender`
        //       is deposited in, up to `amount` tokens. The withdraw action can be expensive,
        //       so it if there is a denial of service issue in withdrawing, the downstream usage
        //       of this router contract must give an alternative method of withdrawing using
        //       this function so that `amount` is less than the full amount requested to withdraw
        //       (e.g. "piece-wise withdrawals"), leading to less loop iterations such that the
        //       DoS issue is mitigated (at a tradeoff of requiring more txns from the end user).
        for (uint256 id = 0; id < vaults.length; id++) {
            if (!withdrawFromBest && vaults[id] == _bestVault) {
                continue; // Don't withdraw from the best
            }

            // Start with the total shares that `sender` has
            uint256 availableShares = vaults[id].balanceOf(sender);

            // Restrict by the allowance that `sender` has to this contract
            // NOTE: No need for allowance check if `sender` is this contract
            if (sender != address(this)) {
                availableShares = Math.min(availableShares, vaults[id].allowance(sender, address(this)));
            }

            // Limit by maximum withdrawal size from each vault
            availableShares = Math.min(availableShares, vaults[id].maxAvailableShares());

            if (availableShares > 0) {
                // Intermediate step to move shares to this contract before withdrawing
                // NOTE: No need for share transfer if this contract is `sender`

                if (amount != WITHDRAW_EVERYTHING) {
                    // Compute amount to withdraw fully to satisfy the request
                    uint256 estimatedShares = ((amount - withdrawn) * (10**uint256(vaults[id].decimals()))) / vaults[id].pricePerShare();
                    // NOTE: Changes every iteration

                    // Limit amount to withdraw to the maximum made available to this contract
                    // NOTE: Avoid corner case where `estimatedShares` isn't precise enough
                    // NOTE: If `0 < estimatedShares < 1` but `availableShares > 1`, this will withdraw more than necessary
                    if (estimatedShares > 0 && estimatedShares < availableShares) {
                        if (sender != address(this)) vaults[id].transferFrom(sender, address(this), estimatedShares);
                        withdrawn = withdrawn + vaults[id].withdraw(estimatedShares);
                    } else {
                        if (sender != address(this)) vaults[id].transferFrom(sender, address(this), availableShares);
                        withdrawn = withdrawn + vaults[id].withdraw(availableShares);
                    }
                } else {
                    if (sender != address(this)) vaults[id].transferFrom(sender, address(this), availableShares);
                    withdrawn = withdrawn + vaults[id].withdraw();
                }

                // Check if we have fully satisfied the request
                // NOTE: use `amount = WITHDRAW_EVERYTHING` for withdrawing everything
                if (amount <= withdrawn) break; // withdrawn as much as we needed
            }
        }

        // If we have extra, deposit back into `_bestVault` for `sender`
        // NOTE: Invariant is `withdrawn <= amount`
        if (withdrawn > amount && ((withdrawn - amount) > _bestVault.pricePerShare() / 10**_bestVault.decimals())) {
            // Don't forget to approve the deposit
            if (token.allowance(address(this), address(_bestVault)) < withdrawn - amount) {
                SafeERC20.safeApprove(token, address(_bestVault), UNLIMITED_APPROVAL); // Vaults are trusted
            }

            _bestVault.deposit(withdrawn - amount, sender);
            withdrawn = amount;
        }

        // `receiver` now has `withdrawn` tokens as balance
        if (receiver != address(this)) SafeERC20.safeTransfer(token, receiver, withdrawn);
    }
}

// File: src/interfaces/Angle/IVoteEscrow.sol



// SPDX-License-Identifier: AGPL-3.0
pragma solidity ^0.8.12;
pragma experimental ABIEncoderV2;

interface IVoteEscrow {
    function create_lock(uint256, uint256) external;

    function increase_amount(uint256) external;

    function withdraw() external;
}