// 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/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: @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: 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/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/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/hardworkInterface/IVault.sol

pragma solidity 0.5.16;

interface IVault {

    function underlyingBalanceInVault() external view returns (uint256);
    function underlyingBalanceWithInvestment() external view returns (uint256);

    // function store() external view returns (address);
    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/strategies/SNXRewards/DEGORewardInterface.sol

pragma solidity 0.5.16;

interface DEGORewardInterface {
    function withdraw(uint) external;
    function getReward() external;
    function stake(uint, string calldata) external;
    function balanceOf(address) external view returns (uint);
    function earned(address account) external view returns (uint256);
    function exit() external;
}

// 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 view 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/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/uniswap/interfaces/IUniswapV2Pair.sol

/**
 *Submitted for verification at Etherscan.io on 2020-05-05
*/

// File: contracts/interfaces/IUniswapV2Pair.sol

pragma solidity >=0.5.0;

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Mint(address indexed sender, uint amount0, uint amount1);
    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function mint(address to) external returns (uint liquidity);
    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

// File: contracts/strategies/LiquidityRecipient.sol

pragma solidity 0.5.16;







contract LiquidityRecipient is Controllable {

  using SafeMath for uint256;
  using SafeERC20 for IERC20;

  event LiquidityProvided(uint256 farmIn, uint256 wethIn, uint256 lpOut);
  event LiquidityRemoved(uint256 lpIn, uint256 wethOut, uint256 farmOut);

  modifier onlyStrategy() {
    require(msg.sender == wethStrategy, "only the weth strategy");
    _;
  }

  modifier onlyStrategyOrGovernance() {
    require(msg.sender == wethStrategy || msg.sender == governance(),
      "only not the weth strategy or governance");
    _;
  }

  // Address for WETH
  address public weth;

  // Address for FARM
  address public farm;

  // The WETH strategy this contract is hooked up to. The strategy cannot be changed.
  address public wethStrategy;

  // The treasury to provide FARM, and to receive FARM or overdraft weth
  address public treasury;

  // The address of the uniswap router
  address public uniswap;

  // The UNI V2 LP token matching the pool
  address public uniLp;

  // These tokens cannot be claimed by the controller
  mapping(address => bool) public unsalvagableTokens;

  constructor(
    address _storage,
    address _weth,
    address _farm,
    address _treasury,
    address _uniswap,
    address _uniLp,
    address _wethStrategy
  )
  Controllable(_storage)
  public {
    weth = _weth;
    farm = _farm;
    require(_treasury != address(0), "treasury cannot be address(0)");
    treasury = _treasury;
    uniswap = _uniswap;
    require(_uniLp != address(0), "uniLp cannot be address(0)");
    uniLp = _uniLp;
    unsalvagableTokens[_weth] = true;
    unsalvagableTokens[_uniLp] = true;
    wethStrategy = _wethStrategy;
  }

  /**
  * Adds liquidity to Uniswap.
  */
  function addLiquidity() internal {
    uint256 farmBalance = IERC20(farm).balanceOf(address(this));
    uint256 wethBalance = IERC20(weth).balanceOf(address(this));

    IERC20(farm).safeApprove(uniswap, 0);
    IERC20(farm).safeApprove(uniswap, farmBalance);
    IERC20(weth).safeApprove(uniswap, 0);
    IERC20(weth).safeApprove(uniswap, wethBalance);

    (uint256 amountFarm,
    uint256 amountWeth,
    uint256 liquidity) = IUniswapV2Router02(uniswap).addLiquidity(farm,
        weth,
        farmBalance,
        wethBalance,
        0,
        0,
        address(this),
        block.timestamp);

    emit LiquidityProvided(amountFarm, amountWeth, liquidity);
  }

  /**
  * Removes liquidity from Uniswap.
  */
  function removeLiquidity() internal {
    uint256 lpBalance = IERC20(uniLp).balanceOf(address(this));
    if (lpBalance > 0) {
      IERC20(uniLp).safeApprove(uniswap, 0);
      IERC20(uniLp).safeApprove(uniswap, lpBalance);
      (uint256 amountFarm, uint256 amountWeth) = IUniswapV2Router02(uniswap).removeLiquidity(farm,
        weth,
        lpBalance,
        0,
        0,
        address(this),
        block.timestamp
      );
      emit LiquidityRemoved(lpBalance, amountWeth, amountFarm);
    } else {
      emit LiquidityRemoved(0, 0, 0);
    }
  }

  /**
  * Adds liquidity to Uniswap. There is no vault for this cannot be invoked via controller. It has
  * to be restricted for market manipulation reasons, so only governance can call this method.
  */
  function doHardWork() public onlyGovernance {
    addLiquidity();
  }

  /**
  * Borrows the set amount of WETH from the strategy, and will invest all available liquidity
  * to Uniswap. This assumes that an approval from the strategy exists.
  */
  function takeLoan(uint256 amount) public onlyStrategy {
    IERC20(weth).safeTransferFrom(wethStrategy, address(this), amount);
    addLiquidity();
  }

  /**
  * Prepares for settling the loan to the strategy by withdrawing all liquidity from Uniswap,
  * and providing approvals to the strategy (for WETH) and to treasury (for FARM). The strategy
  * will make the WETH withdrawal by the pull pattern, and so will the treasury.
  */
  function settleLoan() public onlyStrategyOrGovernance {
    removeLiquidity();
    IERC20(weth).safeApprove(wethStrategy, 0);
    IERC20(weth).safeApprove(wethStrategy, uint256(-1));
    IERC20(farm).safeApprove(treasury, 0);
    IERC20(farm).safeApprove(treasury, uint256(-1));
  }

  /**
  * If Uniswap returns less FARM and more WETH, the WETH excess will be present in this strategy.
  * The governance can send this WETH to the treasury by invoking this function through the
  * strategy. The strategy ensures that this function is not called unless the entire WETH loan
  * was settled.
  */
  function wethOverdraft() external onlyStrategy {
    IERC20(weth).safeTransfer(treasury, IERC20(weth).balanceOf(address(this)));
  }

  /**
  * Salvages a token.
  */
  function salvage(address recipient, address token, uint256 amount) external onlyGovernance {
    // To make sure that governance cannot come in and take away the coins
    require(!unsalvagableTokens[token], "token is defined as not salvagable");
    IERC20(token).safeTransfer(recipient, amount);
  }
}

// File: contracts/strategies/SNXRewards/DEGOSimpleStrategy.sol

pragma solidity 0.5.16;













/*
*   This is a general strategy for yields that are based on the synthetix reward contract
*   for example, yam, spaghetti, ham, shrimp.
*
*   One strategy is deployed for one underlying asset, but the design of the contract
*   should allow it to switch between different reward contracts.
*
*   It is important to note that not all SNX reward contracts that are accessible via the same interface are
*   suitable for this Strategy. One concrete example is CREAM.finance, as it implements a "Lock" feature and
*   would not allow the user to withdraw within some timeframe after the user have deposited.
*   This would be problematic to user as our "invest" function in the vault could be invoked by anyone anytime
*   and thus locking/reverting on subsequent withdrawals. Another variation is the YFI Governance: it can
*   activate a vote lock to stop withdrawal.
*
*   Ref:
*   1. CREAM https://etherscan.io/address/0xc29e89845fa794aa0a0b8823de23b760c3d766f5#code
*   2. YAM https://etherscan.io/address/0x8538E5910c6F80419CD3170c26073Ff238048c9E#code
*   3. SHRIMP https://etherscan.io/address/0x9f83883FD3cadB7d2A83a1De51F9Bf483438122e#code
*   4. BASED https://etherscan.io/address/0x5BB622ba7b2F09BF23F1a9b509cd210A818c53d7#code
*   5. YFII https://etherscan.io/address/0xb81D3cB2708530ea990a287142b82D058725C092#code
*   6. YFIGovernance https://etherscan.io/address/0xBa37B002AbaFDd8E89a1995dA52740bbC013D992#code
*
*
*
*   Respecting the current system design of choosing the best strategy under the vault, and also rewarding/funding
*   the public key that invokes the switch of strategies, this smart contract should be deployed twice and linked
*   to the same vault. When the governance want to rotate the crop, they would set the reward source on the strategy
*   that is not active, then set that apy higher and this one lower.
*
*   Consequently, in the smart contract we restrict that we can only set a new reward source when it is not active.
*
*/

contract DEGOSimpleStrategy is IStrategy, Controllable, ProfitNotifier {

  using SafeMath for uint256;
  using SafeERC20 for IERC20;

  ERC20Detailed public underlying; // underlying here would be Uniswap's LP Token / Pair token

  address public vault;
  bool pausedInvesting = false; // When this flag is true, the strategy will not be able to invest. But users should be able to withdraw.

  DEGORewardInterface public rewardPool;
  address public rewardToken; // unfortunately, the interface is not unified for rewardToken for all the variants

  // a flag for disabling selling for simplified emergency exit
  bool public sell = true;
  uint256 public sellFloor = 10e16;

  // UniswapV2Router02
  // https://uniswap.org/docs/v2/smart-contracts/router02/
  // https://etherscan.io/address/0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
  address public constant uniswapRouterV2 = address(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);

  address[] public uniswapRoute;

  // These tokens cannot be claimed by the controller
  mapping (address => bool) public unsalvagableTokens;

  // The strategy supplying liquidity to Uniswap
  address public liquidityRecipient;
  // The current loan
  uint256 public liquidityLoanCurrent;
  // The target loan
  uint256 public liquidityLoanTarget;

  uint256 public constant tenWeth = 10 * 1e18;

  event ProfitsNotCollected();

  modifier restricted() {
    require(msg.sender == vault || msg.sender == controller()
      || msg.sender == governance(),
      "The sender has to be the controller, governance, or vault");
    _;
  }

  // This is only used in `investAllUnderlying()`
  // The user can still freely withdraw from the strategy
  modifier onlyNotPausedInvesting() {
    require(!pausedInvesting, "Action blocked as the strategy is in emergency state");
    _;
  }

  constructor(
    address _storage,
    address _underlying,
    address _vault,
    address _rewardPool,
    address _rewardToken
  )
  ProfitNotifier(_storage, _underlying)
  public {
    underlying = ERC20Detailed(_underlying);
    vault = _vault;
    rewardPool = DEGORewardInterface(_rewardPool);
    rewardToken = _rewardToken;

    unsalvagableTokens[_underlying] = true;
    unsalvagableTokens[_rewardToken] = true;
  }

  function depositArbCheck() public view returns(bool) {
    return true;
  }

  /*
  *   In case there are some issues discovered about the pool or underlying asset
  *   Governance can exit the pool properly
  *   The function is only used for emergency to exit the pool
  */
  function emergencyExit() public onlyGovernance {
    rewardPool.exit();
    pausedInvesting = true;
  }

  /*
  *   Resumes the ability to invest into the underlying reward pools
  */

  function continueInvesting() public onlyGovernance {
    pausedInvesting = false;
  }

  /**
  * Sets the route for liquidating the reward token to the underlying token
  */
  function setLiquidationRoute(address[] memory _uniswapRoute) public onlyGovernance {
    require(rewardToken == _uniswapRoute[0],
      "The first token of the Uniswap route must be the reward token");
    require(address(underlying) == _uniswapRoute[(_uniswapRoute.length).sub(1)],
      "The last token of the Uniswap route must be the underlying token");

    uniswapRoute = _uniswapRoute;
  }

  // We assume that all the tradings can be done on Uniswap
  function _liquidateReward() internal {
    uint256 rewardBalance = IERC20(rewardToken).balanceOf(address(this));
    uint256 initialUnderlyingBalance = IERC20(underlying).balanceOf(address(this));
    if (!sell || rewardBalance < sellFloor || uniswapRoute.length == 0) {
      // Profits can be disabled for possible simplified and rapid exit
      emit ProfitsNotCollected();
      return;
    }

    if (rewardBalance > 0 ) {

      // allow Uniswap to sell our reward
      uint256 amountOutMin = 1;

      IERC20(rewardToken).safeApprove(uniswapRouterV2, 0);
      IERC20(rewardToken).safeApprove(uniswapRouterV2, rewardBalance);

      // sell DEGO for underlying
      // we can accept 1 as minimum because this is called only by a trusted role

      IUniswapV2Router02(uniswapRouterV2).swapExactTokensForTokensSupportingFeeOnTransferTokens(
        rewardBalance,
        amountOutMin,
        uniswapRoute,
        address(this),
        block.timestamp
      );
    }

    notifyProfit(initialUnderlyingBalance, IERC20(underlying).balanceOf(address(this)));
  }

  /*
  *   Stakes everything the strategy holds into the reward pool
  */
  function investAllUnderlying() public restricted onlyNotPausedInvesting {
    // this check is needed, because most of the SNX reward pools will revert if
    // you try to stake(0).
    if(underlying.balanceOf(address(this)) > 0) {
      IERC20(underlying).safeApprove(address(rewardPool), underlying.balanceOf(address(this)));
      // DEGO has a referal code as the second parameter, leaving it blank since we don't have any
      rewardPool.stake(underlying.balanceOf(address(this)), "");
    }
  }

  /*
  *   Withdraws all the asset to the vault
  */
  function withdrawAllToVault() public restricted {
    if (address(rewardPool) != address(0)) {
      rewardPool.exit();
    }
    _liquidateReward();
    IERC20(underlying).safeTransfer(vault, underlying.balanceOf(address(this)));
  }

  function withdrawAll() public onlyGovernance {
    if (address(rewardPool) != address(0)) {
      rewardPool.exit();
    }
    _liquidateReward();
  }

  /*
  *   Withdraws all the asset to the vault
  */
  function withdrawToVault(uint256 amount) public restricted {
    // Typically there wouldn't be any amount here
    // however, it is possible because of the emergencyExit
    if(amount > underlying.balanceOf(address(this))){
      // While we have the check above, we still using SafeMath below
      // for the peace of mind (in case something gets changed in between)
      uint256 needToWithdraw = amount.sub(underlying.balanceOf(address(this)));
      rewardPool.withdraw(Math.min(rewardPool.balanceOf(address(this)), needToWithdraw));
    }

    IERC20(underlying).safeTransfer(vault, amount);
  }

  /*
  *   Note that we currently do not have a mechanism here to include the
  *   amount of reward that is accrued.
  */
  function investedUnderlyingBalance() public view returns (uint256) {
    if (address(rewardPool) == address(0)) {
      return underlying.balanceOf(address(this));
    }
    // Adding the amount locked in the reward pool and the amount that is somehow in this contract
    // both are in the units of "underlying"
    // The second part is needed because there is the emergency exit mechanism
    // which would break the assumption that all the funds are always inside of the reward pool
    return rewardPool.balanceOf(address(this)).add(underlying.balanceOf(address(this)));
  }

  /*
  *   Governance or Controller can claim coins that are somehow transferred into the contract
  *   Note that they cannot come in take away coins that are used and defined in the strategy itself
  *   Those are protected by the "unsalvagableTokens". To check, see where those are being flagged.
  */
  function salvage(address recipient, address token, uint256 amount) external onlyControllerOrGovernance {
     // To make sure that governance cannot come in and take away the coins
    require(!unsalvagableTokens[token], "token is defined as not salvagable");
    IERC20(token).safeTransfer(recipient, amount);
  }

  /*
  *   Get the reward, sell it in exchange for underlying, invest what you got.
  *   It's not much, but it's honest work.
  *
  *   Note that although `onlyNotPausedInvesting` is not added here,
  *   calling `investAllUnderlying()` affectively blocks the usage of `doHardWork`
  *   when the investing is being paused by governance.
  */
  function doHardWork() external onlyNotPausedInvesting restricted {
    rewardPool.getReward();
    _liquidateReward();
    investAllUnderlying();
  }

  /**
  * Can completely disable claiming UNI 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;
  }

  /**
  * Provides a loan to the liquidity strategy. Sends in funds to fill out the loan target amount,
  * if they are available.
  */
  function provideLoan() public onlyGovernance {

    if (liquidityLoanCurrent < liquidityLoanTarget
      && IERC20(underlying).balanceOf(address(this)) > 0
      && liquidityRecipient != address(0)) {
      uint256 diff = Math.min(
        liquidityLoanTarget.sub(liquidityLoanCurrent), 
        IERC20(underlying).balanceOf(address(this))
      );
      IERC20(underlying).safeApprove(liquidityRecipient, 0);
      IERC20(underlying).safeApprove(liquidityRecipient, diff);
      // use the pull pattern so that this fails if the contract is not set properly
      LiquidityRecipient(liquidityRecipient).takeLoan(diff);
      liquidityLoanCurrent = liquidityLoanCurrent.add(diff);
    }

  }

  /**
  * Settles a loan amount by forcing withdrawal inside the liquidity strategy, and then transferring
  * the funds back to this strategy. This way, the loan can be settled partially, or completely.
  * The method can be invoked only by EOAs to avoid market manipulation, and only by the governance
  * unless there is not more than 10 WETH left in this strategy.
  */
  function settleLoan(uint256 amount) public {
    require(
      // the only funds in are in the loan, other than 10 WETH
      investedUnderlyingBalance() <= liquidityLoanCurrent.add(tenWeth)
      // or the governance wants this to happen
      || msg.sender == governance(), 
      "Buffer exists and the caller is not governance"
    );
    // market manipulation prevention
    require(tx.origin == msg.sender, "no smart contracts");

    if(liquidityLoanCurrent == 0)
      return ;

    LiquidityRecipient(liquidityRecipient).settleLoan();
    IERC20(underlying).safeTransferFrom(liquidityRecipient, address(this), amount);
    liquidityLoanCurrent = liquidityLoanCurrent.sub(amount);
    if (liquidityLoanCurrent == 0) {
      LiquidityRecipient(liquidityRecipient).wethOverdraft();
    }
  }
  
  function setLiquidityRecipient(address recipient) public onlyGovernance {
    require(liquidityRecipient == address(0) || liquidityLoanCurrent == 0,
      "Liquidity recipient was already set, and has a loan");
    liquidityRecipient = recipient;
  }

  function setLiquidityLoanTarget(uint256 target) public onlyGovernance {
    liquidityLoanTarget = target;
  }

}