// File: @openzeppelin/contracts/math/Math.sol

pragma solidity ^0.5.0;

/**
 * @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, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}

// File: @openzeppelin/contracts/math/SafeMath.sol

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/utils/Address.sol

pragma solidity ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following 
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }

    /**
     * @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].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol

pragma solidity ^0.5.0;




/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20Detailed.sol

pragma solidity ^0.5.0;


/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is IERC20 {
    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol, uint8 decimals) public {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view 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.
     *
     * 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 returns (uint8) {
        return _decimals;
    }
}

// File: contracts/strategies/curve/interfaces/Gauge.sol

pragma solidity 0.5.16;

interface Gauge {
    function deposit(uint) external;
    function balanceOf(address) external view returns (uint);
    function withdraw(uint) external;
    function user_checkpoint(address) external;
}

interface VotingEscrow {
    function create_lock(uint256 v, uint256 time) external;
    function increase_amount(uint256 _value) external;
    function increase_unlock_time(uint256 _unlock_time) external;
    function withdraw() external;
}

interface Mintr {
    function mint(address) external;
}

// File: contracts/strategies/curve/interfaces/ISwerveFi.sol

pragma solidity 0.5.16;

interface ISwerveFi {
  function get_virtual_price() external view returns (uint);
  function add_liquidity(
    uint256[4] calldata amounts,
    uint256 min_mint_amount
  ) external;
  function remove_liquidity_imbalance(
    uint256[4] calldata amounts,
    uint256 max_burn_amount
  ) external;
  function remove_liquidity(
    uint256 _amount,
    uint256[4] calldata amounts
  ) external;
  function exchange(
    int128 from, int128 to, uint256 _from_amount, uint256 _min_to_amount
  ) external;
  function calc_token_amount(
    uint256[4] calldata amounts,
    bool deposit
  ) external view returns(uint);
  function calc_withdraw_one_coin(
    uint256 _token_amount, int128 i) external view returns (uint256);
  function remove_liquidity_one_coin(uint256 _token_amount, int128 i,
    uint256 min_amount) external;
}

// File: contracts/strategies/curve/interfaces/yVault.sol

pragma solidity 0.5.16;

interface yERC20 {
  function deposit(uint256 _amount) external;
  function withdraw(uint256 _amount) external;
  function getPricePerFullShare() external view returns (uint256);
}

// File: contracts/strategies/curve/interfaces/IPriceConvertor.sol

pragma solidity 0.5.16;

interface IPriceConvertor {
  function yCrvToUnderlying(uint256 _token_amount, uint256 i) external view returns (uint256);
}

// File: contracts/hardworkInterface/IController.sol

pragma solidity 0.5.16;

interface IController {
    // [Grey list]
    // An EOA can safely interact with the system no matter what.
    // If you're using Metamask, you're using an EOA.
    // Only smart contracts may be affected by this grey list.
    //
    // This contract will not be able to ban any EOA from the system
    // even if an EOA is being added to the greyList, he/she will still be able
    // to interact with the whole system as if nothing happened.
    // Only smart contracts will be affected by being added to the greyList.
    // This grey list is only used in Vault.sol, see the code there for reference
    function greyList(address _target) external returns(bool);

    function addVaultAndStrategy(address _vault, address _strategy) external;
    function doHardWork(address _vault) external;
    function hasVault(address _vault) external returns(bool);

    function salvage(address _token, uint256 amount) external;
    function salvageStrategy(address _strategy, address _token, uint256 amount) external;

    function notifyFee(address _underlying, uint256 fee) external;
    function profitSharingNumerator() external view returns (uint256);
    function profitSharingDenominator() external view returns (uint256);
}

// File: contracts/Storage.sol

pragma solidity 0.5.16;

contract Storage {

  address public governance;
  address public controller;

  constructor() public {
    governance = msg.sender;
  }

  modifier onlyGovernance() {
    require(isGovernance(msg.sender), "Not governance");
    _;
  }

  function setGovernance(address _governance) public onlyGovernance {
    require(_governance != address(0), "new governance shouldn't be empty");
    governance = _governance;
  }

  function setController(address _controller) public onlyGovernance {
    require(_controller != address(0), "new controller shouldn't be empty");
    controller = _controller;
  }

  function isGovernance(address account) public view returns (bool) {
    return account == governance;
  }

  function isController(address account) public view returns (bool) {
    return account == controller;
  }
}

// File: contracts/Governable.sol

pragma solidity 0.5.16;


contract Governable {

  Storage public store;

  constructor(address _store) public {
    require(_store != address(0), "new storage shouldn't be empty");
    store = Storage(_store);
  }

  modifier onlyGovernance() {
    require(store.isGovernance(msg.sender), "Not governance");
    _;
  }

  function setStorage(address _store) public onlyGovernance {
    require(_store != address(0), "new storage shouldn't be empty");
    store = Storage(_store);
  }

  function governance() public view returns (address) {
    return store.governance();
  }
}

// File: contracts/Controllable.sol

pragma solidity 0.5.16;


contract Controllable is Governable {

  constructor(address _storage) Governable(_storage) public {
  }

  modifier onlyController() {
    require(store.isController(msg.sender), "Not a controller");
    _;
  }

  modifier onlyControllerOrGovernance(){
    require((store.isController(msg.sender) || store.isGovernance(msg.sender)),
      "The caller must be controller or governance");
    _;
  }

  function controller() public view returns (address) {
    return store.controller();
  }
}

// File: contracts/strategies/ProfitNotifier.sol

pragma solidity 0.5.16;






contract ProfitNotifier is Controllable {
  using SafeMath for uint256;
  using SafeERC20 for IERC20;

  uint256 public profitSharingNumerator;
  uint256 public profitSharingDenominator;
  address public underlying;

  event ProfitLog(
    uint256 oldBalance,
    uint256 newBalance,
    uint256 feeAmount,
    uint256 timestamp
  );

  constructor(
    address _storage,
    address _underlying
  ) public Controllable(_storage){
    underlying = _underlying;
    // persist in the state for immutability of the fee
    profitSharingNumerator = 30; //IController(controller()).profitSharingNumerator();
    profitSharingDenominator = 100; //IController(controller()).profitSharingDenominator();
    require(profitSharingNumerator < profitSharingDenominator, "invalid profit share");
  }

  function notifyProfit(uint256 oldBalance, uint256 newBalance) internal {
    if (newBalance > oldBalance) {
      uint256 profit = newBalance.sub(oldBalance);
      uint256 feeAmount = profit.mul(profitSharingNumerator).div(profitSharingDenominator);
      emit ProfitLog(oldBalance, newBalance, feeAmount, block.timestamp);

      IERC20(underlying).safeApprove(controller(), 0);
      IERC20(underlying).safeApprove(controller(), feeAmount);
      IController(controller()).notifyFee(
        underlying,
        feeAmount
      );
    } else {
      emit ProfitLog(oldBalance, newBalance, 0, block.timestamp);
    }
  }
}

// File: contracts/hardworkInterface/IVault.sol

pragma solidity 0.5.16;


interface IVault {
    // the IERC20 part is the share

    function underlyingBalanceInVault() external view returns (uint256);
    function underlyingBalanceWithInvestment() external view returns (uint256);

    function governance() external view returns (address);
    function controller() external view returns (address);
    function underlying() external view returns (address);
    function strategy() external view returns (address);

    function setStrategy(address _strategy) external;
    function setVaultFractionToInvest(uint256 numerator, uint256 denominator) external;

    function deposit(uint256 amountWei) external;
    function depositFor(uint256 amountWei, address holder) external;

    function withdrawAll() external;
    function withdraw(uint256 numberOfShares) external;
    function getPricePerFullShare() external view returns (uint256);

    function underlyingBalanceWithInvestmentForHolder(address holder) view external returns (uint256);

    // hard work should be callable only by the controller (by the hard worker) or by governance
    function doHardWork() external;
    function rebalance() external;
}

// File: contracts/hardworkInterface/IStrategy.sol

pragma solidity 0.5.16;


interface IStrategy {
    
    function unsalvagableTokens(address tokens) external view returns (bool);
    
    function governance() external view returns (address);
    function controller() external view returns (address);
    function underlying() external view returns (address);
    function vault() external view returns (address);

    function withdrawAllToVault() external;
    function withdrawToVault(uint256 amount) external;

    function investedUnderlyingBalance() external view returns (uint256); // itsNotMuch()

    // should only be called by controller
    function salvage(address recipient, address token, uint256 amount) external;

    function doHardWork() external;
    function depositArbCheck() external view returns(bool);
}

// File: contracts/uniswap/interfaces/IUniswapV2Router01.sol

pragma solidity >=0.5.0;

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

// File: contracts/uniswap/interfaces/IUniswapV2Router02.sol

pragma solidity >=0.5.0;


interface IUniswapV2Router02 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);

    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

// File: contracts/strategies/curve/CRVStrategySwerve.sol

pragma solidity 0.5.16;

















// This is an exact clone of the WBTC strategy
// Naming was not adjusted for easy diff
contract CRVStrategySwerve is IStrategy, ProfitNotifier {

  enum TokenIndex {DAI, USDC, USDT, TUSD}

  using SafeERC20 for IERC20;
  using Address for address;
  using SafeMath for uint256;

  // wbtc token address (or ren if we want both)
  address public wbtc;

  // the matching enum record used to determine the index
  TokenIndex tokenIndex;

  // our vault holding the wbtc asset
  address public vault;

  // our vault for depositing the mixToken tokens
  address public mixVault;

  // the address of mixToken token
  address public mixToken;

  // the address of the Curve protocol's pool for REN + WBTC
  address public curve;

  // these tokens cannot be claimed by the governance
  mapping(address => bool) public unsalvagableTokens;

  // the wbtc gauge in Curve
  address public gauge;

  // the reward minter
  address public mintr;

  // the address for the CRV token
  address public crv;

  // uniswap router address
  address public uni;

  // price checkpoint preventing attacks
  uint256 public wbtcPriceCheckpoint;

  // a unit for the price checkpoint
  uint256 public mixTokenUnit;

  // settable arbitrage tolerance
  uint256 public arbTolerance = 3;

  // liquidation path to be used
  address[] public uniswap_CRV2WBTC;

  // a flag for disabling selling for simplified emergency exit
  bool public sell = true;

  // minimum CRV amount to be liquidation
  uint256 public sellFloor = 30e18;

  event Liquidating(uint256 amount);
  event ProfitsNotCollected();


  modifier restricted() {
    require(msg.sender == vault || msg.sender == controller()
      || msg.sender == governance(),
      "The sender has to be the controller, governance, or vault");
    _;
  }

  constructor(
    address _storage,
    address _wbtc,
    address _vault,
    uint256 _tokenIndex,
    address _mixToken,
    address _curvePool,
    address _crv,
    address _weth,
    address _gauge,
    address _mintr,
    address _uniswap
  )
  ProfitNotifier(_storage, _wbtc) public {
    vault = _vault;
    wbtc = _wbtc;
    tokenIndex = TokenIndex(_tokenIndex);
    mixToken = _mixToken;
    curve = _curvePool;
    gauge = _gauge;
    crv = _crv;
    uni = _uniswap;
    mintr = _mintr;

    uniswap_CRV2WBTC = [_crv, _weth, _wbtc];

    // set these tokens to be not salvageable
    unsalvagableTokens[wbtc] = true;
    unsalvagableTokens[mixToken] = true;
    unsalvagableTokens[crv] = true;

    mixTokenUnit = 10 ** 18;
    
    // starting with a stable price, the mainnet will override this value
    wbtcPriceCheckpoint = mixTokenUnit;
  }

  function depositArbCheck() public view returns(bool) {
    uint256 currentPrice = wbtcValueFromMixToken(mixTokenUnit);
    if (currentPrice > wbtcPriceCheckpoint) {
      return currentPrice.mul(100).div(wbtcPriceCheckpoint) > 100 - arbTolerance;
    } else {
      return wbtcPriceCheckpoint.mul(100).div(currentPrice) > 100 - arbTolerance;
    }
  }

  function setArbTolerance(uint256 tolerance) external onlyGovernance {
    require(tolerance <= 100, "at most 100");
    arbTolerance = tolerance;
  }

  /**
  * Uses the Curve protocol to convert the wbtc asset into to mixed renwbtc token.
  */
  function mixFromWBTC() internal {
    uint256 wbtcBalance = IERC20(wbtc).balanceOf(address(this));
    if (wbtcBalance > 0) {
      IERC20(wbtc).safeApprove(curve, 0);
      IERC20(wbtc).safeApprove(curve, wbtcBalance);
      // we can accept 0 as minimum because this is called only by a trusted role
      uint256 minimum = 0;
      uint256[4] memory coinAmounts = wrapCoinAmount(wbtcBalance);
      ISwerveFi(curve).add_liquidity(
        coinAmounts, minimum
      );
    }
    // now we have the mixed token
  }

  /**
  * Uses the Curve protocol to convert the mixed token back into the wbtc asset. If it cannot
  * acquire the limit amount, it will acquire the maximum it can.
  */
  function mixToWBTC(uint256 wbtcLimit) internal {
    uint256 mixTokenBalance = IERC20(mixToken).balanceOf(address(this));

    // this is the maximum number of wbtc we can get for our mixed token
    uint256 wbtcMaximumAmount = wbtcValueFromMixToken(mixTokenBalance);
    if (wbtcMaximumAmount == 0) {
      return;
    }

    if (wbtcLimit < wbtcMaximumAmount) {
      // we want less than what we can get, we ask for the exact amount
      // now we can remove the liquidity
      uint256[4] memory tokenAmounts = wrapCoinAmount(wbtcLimit);
      IERC20(mixToken).safeApprove(curve, 0);
      IERC20(mixToken).safeApprove(curve, mixTokenBalance);
      ISwerveFi(curve).remove_liquidity_imbalance(
        tokenAmounts, mixTokenBalance
      );
    } else {
      // we want more than we can get, so we withdraw everything
      IERC20(mixToken).safeApprove(curve, 0);
      IERC20(mixToken).safeApprove(curve, mixTokenBalance);
      ISwerveFi(curve).remove_liquidity_one_coin(mixTokenBalance, int128(tokenIndex), 0);
    }
    // now we have wbtc asset
  }

  /**
  * Withdraws an wbtc asset from the strategy to the vault in the specified amount by asking
  * by removing imbalanced liquidity from the Curve protocol. The rest is deposited back to the
  * Curve protocol pool. If the amount requested cannot be obtained, the method will get as much
  * as we have.
  */
  function withdrawToVault(uint256 amountWbtc) external restricted {
    // withdraw all from gauge
    Gauge(gauge).withdraw(Gauge(gauge).balanceOf(address(this)));
    // convert the mix to WBTC, but get at most amountWbtc
    mixToWBTC(amountWbtc);
    // we can transfer the asset to the vault
    uint256 actualBalance = IERC20(wbtc).balanceOf(address(this));
    if (actualBalance > 0) {
      IERC20(wbtc).safeTransfer(vault, Math.min(amountWbtc, actualBalance));
    }

    // invest back the rest
    investAllUnderlying();
  }

  /**
  * Withdraws all assets from the vault.
  */
  function withdrawAllToVault() external restricted {
    // withdraw all from gauge
    Gauge(gauge).withdraw(Gauge(gauge).balanceOf(address(this)));
    // convert the mix to WBTC, we want the entire balance
    mixToWBTC(uint256(~0));
    // we can transfer the asset to the vault
    uint256 actualBalance = IERC20(wbtc).balanceOf(address(this));
    if (actualBalance > 0) {
      IERC20(wbtc).safeTransfer(vault, actualBalance);
    }
  }

  /**
  * Invests all wbtc assets into our mixToken vault.
  */
  function investAllUnderlying() internal {
    // convert the entire balance not yet invested into mixToken first
    mixFromWBTC();

    // then deposit into the mixToken vault
    uint256 mixTokenBalance = IERC20(mixToken).balanceOf(address(this));
    if (mixTokenBalance > 0) {
      IERC20(mixToken).safeApprove(gauge, 0);
      IERC20(mixToken).safeApprove(gauge, mixTokenBalance);
      Gauge(gauge).deposit(mixTokenBalance);
    }
  }

  /**
  * The hard work only invests all wbtc assets, and then tells the controller to call hard
  * work on the mixToken vault.
  */
  function doHardWork() public restricted {
    claimAndLiquidateCrv();
    investAllUnderlying();
    wbtcPriceCheckpoint = wbtcValueFromMixToken(mixTokenUnit);
  }

  /**
  * Salvages a token. We cannot salvage mixToken tokens, CRV, or wbtc assets.
  */
  function salvage(address recipient, address token, uint256 amount) public onlyGovernance {
    // To make sure that governance cannot come in and take away the coins
    require(!unsalvagableTokens[token], "token is defined as not salvageable");
    IERC20(token).safeTransfer(recipient, amount);
  }

  /**
  * Returns the wbtc invested balance. The is the wbtc amount in this stragey, plus the gauge
  * amount of the mixed token converted back to wbtc.
  */
  function investedUnderlyingBalance() public view returns (uint256) {
    uint256 gaugeBalance = Gauge(gauge).balanceOf(address(this));
    uint256 wbtcBalance = IERC20(wbtc).balanceOf(address(this));
    if (gaugeBalance == 0) {
      // !!! if we have 0 balance in gauge, the conversion to wbtc reverts in Curve
      // !!! this if-statement is necessary to avoid transaction reverts
      return wbtcBalance;
    }
    uint256 investedBalance = wbtcValueFromMixToken(gaugeBalance);
    return investedBalance.add(wbtcBalance);
  }

  function wbtcValueFromMixToken(uint256 mixTokenBalance) public view returns (uint256) {
    return ISwerveFi(curve).calc_withdraw_one_coin(mixTokenBalance,
      int128(tokenIndex));
  }

  /**
  * Wraps the coin amount in the array for interacting with the Curve protocol
  */
  function wrapCoinAmount(uint256 amount) internal view returns (uint256[4] memory) {
    uint256[4] memory amounts = [uint256(0), uint256(0), uint256(0), uint256(0)];
    amounts[uint56(tokenIndex)] = amount;
    return amounts;
  }

  /**
  * Claims the CRV crop, converts it to WBTC/renWBTC on Uniswap
  */
  function claimAndLiquidateCrv() internal {
    if (!sell) {
      // Profits can be disabled for possible simplified and rapid exit
      emit ProfitsNotCollected();
      return;
    }
    Mintr(mintr).mint(gauge);
    // claiming rewards and liquidating them
    uint256 crvBalance = IERC20(crv).balanceOf(address(this));
    emit Liquidating(crvBalance);
    if (crvBalance > sellFloor) {
      uint256 wbtcBalanceBefore = IERC20(wbtc).balanceOf(address(this));
      IERC20(crv).safeApprove(uni, 0);
      IERC20(crv).safeApprove(uni, crvBalance);
      // we can accept 1 as the minimum because this will be called only by a trusted worker
      IUniswapV2Router02(uni).swapExactTokensForTokens(
        crvBalance, 1, uniswap_CRV2WBTC, address(this), block.timestamp
      );

      // now we have WBTC
      notifyProfit(wbtcBalanceBefore, IERC20(wbtc).balanceOf(address(this)));
    }
  }

  /**
  * Can completely disable claiming CRV rewards and selling. Good for emergency withdraw in the
  * simplest possible way.
  */
  function setSell(bool s) public onlyGovernance {
    sell = s;
  }

  /**
  * Sets the minimum amount of CRV needed to trigger a sale.
  */
  function setSellFloor(uint256 floor) public onlyGovernance {
    sellFloor = floor;
  }

  /**
  * Creates a Swerve lock
  */
  function createLock(address lockToken, address escrow, uint256 value,
    uint256 unlockTime) public onlyGovernance {
    IERC20(lockToken).safeApprove(escrow, 0);
    IERC20(lockToken).safeApprove(escrow, value);
    VotingEscrow(escrow).create_lock(value, unlockTime);
  }

  /**
  * Checkpoints the Swerve lock balance
  */
  function checkpoint(address _gauge) public onlyGovernance {
    Gauge(_gauge).user_checkpoint(address(this));
  }

  /**
  * Increases the lock amount for Swerve
  */
  function increaseAmount(address lockToken, address escrow, uint256 value) public onlyGovernance {
    IERC20(lockToken).safeApprove(escrow, 0);
    IERC20(lockToken).safeApprove(escrow, value);
    VotingEscrow(escrow).increase_amount(value);
  }

  /**
  * Increases the unlock time for Swerve
  */
  function increaseUnlockTime(address escrow, uint256 unlock_time) public onlyGovernance {
    VotingEscrow(escrow).increase_unlock_time(unlock_time);
  }

  /**
  * Withdraws an expired lock
  */
  function withdrawLock(address lockToken, address escrow) public onlyGovernance {
    uint256 balanceBefore = IERC20(lockToken).balanceOf(address(this));
    VotingEscrow(escrow).withdraw();
    uint256 balanceAfter = IERC20(lockToken).balanceOf(address(this));
    if (balanceAfter > balanceBefore) {
      IERC20(lockToken).safeTransfer(msg.sender, balanceAfter.sub(balanceBefore));
    }
  }
}

// File: contracts/strategies/curve/PriceConvertor.sol

pragma solidity 0.5.16;


interface IConvertor {
  function calc_withdraw_one_coin(uint256 _token_amount, int128 i) external view returns (uint256);
}

contract PriceConvertor is IPriceConvertor {

  IConvertor public zap = IConvertor(0xbBC81d23Ea2c3ec7e56D39296F0cbB648873a5d3);

  function yCrvToUnderlying(uint256 _token_amount, uint256 i) public view returns (uint256) {
    // this returning the DAI amount, not yDAI
    return zap.calc_withdraw_one_coin(_token_amount, int128(i));
  }
}

contract MockPriceConvertor is IPriceConvertor {
  function yCrvToUnderlying(uint256 _token_amount, uint256 /* i */) public view returns (uint256) {
    // counting 1:1
    return _token_amount;
  }
}

// File: contracts/strategies/curve/CRVStrategySwerveUSDTMainnet.sol

pragma solidity 0.5.16;



/**
* Adds the mainnet addresses to the CRVStrategyWBTC
*/
contract CRVStrategySwerveUSDTMainnet is CRVStrategySwerve {

  // token addresses
  // using USDT here
  address constant public __usdt = address(0xdAC17F958D2ee523a2206206994597C13D831ec7);
  // mixed token (swerve combo Swerve.fi DAI/USDC/USDT/TUSD (swUSD))
  address constant public __stableMix = address(0x77C6E4a580c0dCE4E5c7a17d0bc077188a83A059);
  // the dao reward token for swerve
  address constant public __swrv = address(0xB8BAa0e4287890a5F79863aB62b7F175ceCbD433);
  address constant public __weth = address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
  // swerve gauge
  address constant public __gauge = address(0xb4d0C929cD3A1FbDc6d57E7D3315cF0C4d6B4bFa);
  // swerve minter
  address constant public __mintr = address(0x2c988c3974AD7E604E276AE0294a7228DEf67974); // _mintr

  // protocols
  // delegate to zap
  address constant public __poolZap = address(0xa746c67eB7915Fa832a4C2076D403D4B68085431);
  address constant public __uniswap = address(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);

  uint256 constant public __tokenIndex = 2;

  constructor(
    address _storage,
    address _vault
  )
  CRVStrategySwerve(
    _storage,
    __usdt,
    _vault,
    __tokenIndex, // token index for USDT
    __stableMix,
    __poolZap, // curve protocol's pool for WBTC
    __swrv, // the reward DAO token address
    __weth,
    __gauge,
    __mintr,
    __uniswap // uniswap
  )
  public {
    wbtcPriceCheckpoint = wbtcValueFromMixToken(mixTokenUnit);
  }
}