// SPDX-License-Identifier: MIT

pragma solidity 0.6.12;

// File: @openzeppelin/contracts/math/SafeMath.sol

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts/GSN/Context.sol

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: @openzeppelin/contracts/utils/Address.sol

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies in extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;
    using Address for address;

    mapping (address => uint256) private _balances;

    mapping (address => mapping (address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol) public {
        _name = name;
        _symbol = symbol;
        _decimals = 18;
    }

    /**
     * @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. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * 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;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal {
        _decimals = decimals_;
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

// File: contracts/vaults/strategies/IStrategy.sol

interface IStrategy {
    function approve(IERC20 _token) external;

    function approveForSpender(IERC20 _token, address spender) external;

    // Deposit tokens to a farm to yield more tokens.
    function deposit(address _vault, uint256 _amount) external;

    // Claim farming tokens
    function claim(address _vault) external;

    // The vault request to harvest the profit
    function harvest(uint256 _bankPoolId) external;

    // Withdraw the principal from a farm.
    function withdraw(address _vault, uint256 _amount) external;

    // Target farming token of this strategy.
    function getTargetToken() external view returns(address);

    function balanceOf(address _vault) external view returns (uint256);

    function pendingReward(address _vault) external view returns (uint256);

    function expectedAPY(address _vault) external view returns (uint256);

    function governanceRescueToken(IERC20 _token) external returns (uint256);
}

// File: contracts/vaults/ValueVaultMaster.sol

/*
 * Here we have a list of constants. In order to get access to an address
 * managed by ValueVaultMaster, the calling contract should copy and define
 * some of these constants and use them as keys.
 * Keys themselves are immutable. Addresses can be immutable or mutable.
 *
 * Vault addresses are immutable once set, and the list may grow:
 * K_VAULT_WETH = 0;
 * K_VAULT_ETH_USDC_UNI_V2_LP = 1;
 * K_VAULT_ETH_WBTC_UNI_V2_LP = 2;
 */

/*
 * ValueVaultMaster manages all the vaults and strategies of our Value Vaults system.
 */
contract ValueVaultMaster {
    address public governance;

    address public bank;
    address public minorPool;
    address public profitSharer;

    address public govToken; // VALUE
    address public yfv; // When harvesting, convert some parts to YFV for govVault
    address public usdc; // we only used USDC to estimate APY

    address public govVault; // YFV -> VALUE, vUSD, vETH and 6.7% profit from Value Vaults
    address public insuranceFund = 0xb7b2Ea8A1198368f950834875047aA7294A2bDAa; // set to Governance Multisig at start
    address public performanceReward = 0x7Be4D5A99c903C437EC77A20CB6d0688cBB73c7f; // set to deploy wallet at start

    uint256 public constant FEE_DENOMINATOR = 10000;
    uint256 public govVaultProfitShareFee = 670; // 6.7% | VIP-1 (https://yfv.finance/vip-vote/vip_1)
    uint256 public gasFee = 50; // 0.5% at start and can be set by governance decision

    uint256 public minStakeTimeToClaimVaultReward = 24 hours;

    mapping(address => bool) public isVault;
    mapping(uint256 => address) public vaultByKey;

    mapping(address => bool) public isStrategy;
    mapping(uint256 => address) public strategyByKey;
    mapping(address => uint256) public strategyQuota;

    constructor(address _govToken, address _yfv, address _usdc) public {
        govToken = _govToken;
        yfv = _yfv;
        usdc = _usdc;
        governance = tx.origin;
    }

    function setGovernance(address _governance) external {
        require(msg.sender == governance, "!governance");
        governance = _governance;
    }

    // Immutable once set.
    function setBank(address _bank) external {
        require(msg.sender == governance, "!governance");
        require(bank == address(0));
        bank = _bank;
    }

    // Mutable in case we want to upgrade the pool.
    function setMinorPool(address _minorPool) external {
        require(msg.sender == governance, "!governance");
        minorPool = _minorPool;
    }

    // Mutable in case we want to upgrade this module.
    function setProfitSharer(address _profitSharer) external {
        require(msg.sender == governance, "!governance");
        profitSharer = _profitSharer;
    }

    // Mutable, in case governance want to upgrade VALUE to new version
    function setGovToken(address _govToken) external {
        require(msg.sender == governance, "!governance");
        govToken = _govToken;
    }

    // Immutable once added, and you can always add more.
    function addVault(uint256 _key, address _vault) external {
        require(msg.sender == governance, "!governance");
        require(vaultByKey[_key] == address(0), "vault: key is taken");

        isVault[_vault] = true;
        vaultByKey[_key] = _vault;
    }

    // Mutable and removable.
    function addStrategy(uint256 _key, address _strategy) external {
        require(msg.sender == governance, "!governance");
        isStrategy[_strategy] = true;
        strategyByKey[_key] = _strategy;
    }

    // Set 0 to disable quota (no limit)
    function setStrategyQuota(address _strategy, uint256 _quota) external {
        require(msg.sender == governance, "!governance");
        strategyQuota[_strategy] = _quota;
    }

    function removeStrategy(uint256 _key) external {
        require(msg.sender == governance, "!governance");
        isStrategy[strategyByKey[_key]] = false;
        delete strategyByKey[_key];
    }

    function setGovVault(address _govVault) public {
        require(msg.sender == governance, "!governance");
        govVault = _govVault;
    }

    function setInsuranceFund(address _insuranceFund) public {
        require(msg.sender == governance, "!governance");
        insuranceFund = _insuranceFund;
    }

    function setPerformanceReward(address _performanceReward) public{
        require(msg.sender == governance, "!governance");
        performanceReward = _performanceReward;
    }

    function setGovVaultProfitShareFee(uint256 _govVaultProfitShareFee) public {
        require(msg.sender == governance, "!governance");
        govVaultProfitShareFee = _govVaultProfitShareFee;
    }

    function setGasFee(uint256 _gasFee) public {
        require(msg.sender == governance, "!governance");
        gasFee = _gasFee;
    }

    function setMinStakeTimeToClaimVaultReward(uint256 _minStakeTimeToClaimVaultReward) public {
        require(msg.sender == governance, "!governance");
        minStakeTimeToClaimVaultReward = _minStakeTimeToClaimVaultReward;
    }

    /**
     * This function allows governance to take unsupported tokens out of the contract.
     * This is in an effort to make someone whole, should they seriously mess up.
     * There is no guarantee governance will vote to return these.
     * It also allows for removal of airdropped tokens.
     */
    function governanceRecoverUnsupported(IERC20x _token, uint256 amount, address to) external {
        require(msg.sender == governance, "!governance");
        _token.transfer(to, amount);
    }
}

interface IERC20x {
    function transfer(address recipient, uint256 amount) external returns (bool);
}

// File: contracts/vaults/ValueVault.sol

contract ValueVault is ERC20 {
    using SafeMath for uint256;

    address public governance;

    mapping (address => uint256) public lockedAmount;

    IStrategy[] public strategies;

    uint256[] public strategyPreferredOrders;

    ValueVaultMaster public valueVaultMaster;

    constructor (ValueVaultMaster _valueVaultMaster, string memory _name, string memory _symbol) ERC20(_name, _symbol) public  {
        valueVaultMaster = _valueVaultMaster;
        governance = tx.origin;
    }

    function setGovernance(address _governance) external {
        require(msg.sender == governance, "!governance");
        governance = _governance;
    }

    function setStrategies(IStrategy[] memory _strategies) public {
        require(msg.sender == governance, "!governance");
        delete strategies;
        for (uint256 i = 0; i < _strategies.length; ++i) {
            strategies.push(_strategies[i]);
        }
    }

    function setStrategyPreferredOrders(uint256[] memory _strategyPreferredOrders) public {
        require(msg.sender == governance, "!governance");
        delete strategyPreferredOrders;
        for (uint256 i = 0; i < _strategyPreferredOrders.length; ++i) {
            strategyPreferredOrders.push(_strategyPreferredOrders[i]);
        }
    }

    function getStrategyCount() public view returns(uint count) {
        return strategies.length;
    }

    function depositAvailable() public view returns(bool) {
        if (strategies.length == 0) return false;
        for (uint256 i = 0; i < strategies.length; ++i) {
            IStrategy strategy = strategies[i];
            uint256 quota = valueVaultMaster.strategyQuota(address(strategy));
            if (quota == 0 || strategy.balanceOf(address(this)) < quota) {
                return true;
            }
        }
        return false;
    }

    /// @notice Creates `_amount` token to `_to`. Must only be called by ValueVaultBank.
    function mintByBank(IERC20 _token, address _to, uint256 _amount) public {
        require(_msgSender() == valueVaultMaster.bank(), "not bank");

        _deposit(_token, _amount);
        if (_amount > 0) {
            _mint(_to, _amount);
        }
    }

    // Must only be called by ValueVaultBank.
    function burnByBank(IERC20 _token, address _account, uint256 _amount) public {
        require(_msgSender() == valueVaultMaster.bank(), "not bank");

        uint256 balance = balanceOf(_account);
        require(lockedAmount[_account] + _amount <= balance, "Vault: burn too much");

        _withdraw(_token, _amount);
        _burn(_account, _amount);
    }

    // Any user can transfer to another user.
    function transfer(address _to, uint256 _amount) public override returns (bool) {
        uint256 balance = balanceOf(_msgSender());
        require(lockedAmount[_msgSender()] + _amount <= balance, "transfer: <= balance");

        _transfer(_msgSender(), _to, _amount);

        return true;
    }

    function _deposit(IERC20 _token, uint256 _amount) internal {
        require(strategies.length > 0, "no strategies");
        if (strategyPreferredOrders.length == 0 || strategyPreferredOrders.length != strategies.length) {
            for (uint256 i = 0; i < strategies.length; ++i) {
                IStrategy strategy = strategies[i];
                uint256 quota = valueVaultMaster.strategyQuota(address(strategy));
                if (quota == 0 || strategy.balanceOf(address(this)) < quota) {
                    _token.transfer(address(strategy), _amount);
                    strategy.deposit(address(this), _amount);
                    return;
                }
            }
        } else {
            for (uint256 i = 0; i < strategies.length; ++i) {
                IStrategy strategy = strategies[strategyPreferredOrders[i]];
                uint256 quota = valueVaultMaster.strategyQuota(address(strategy));
                if (quota == 0 || strategy.balanceOf(address(this)) < quota) {
                    _token.transfer(address(strategy), _amount);
                    strategy.deposit(address(this), _amount);
                    return;
                }
            }
        }
        revert("Exceeded quota");
    }

    function _withdraw(IERC20 _token, uint256 _amount) internal {
        require(strategies.length > 0, "no strategies");
        if (strategyPreferredOrders.length == 0 || strategyPreferredOrders.length != strategies.length) {
            for (uint256 i = strategies.length; i >= 1; --i) {
                IStrategy strategy = strategies[i - 1];
                uint256 bal = strategy.balanceOf(address(this));
                if (bal > 0) {
                    strategy.withdraw(address(this), (bal > _amount) ? _amount : bal);
                    _token.transferFrom(address(strategy), valueVaultMaster.bank(), _token.balanceOf(address(strategy)));
                    if (_token.balanceOf(valueVaultMaster.bank()) >= _amount) break;
                }
            }
        } else {
            for (uint256 i = strategies.length; i >= 1; --i) {
                IStrategy strategy = strategies[strategyPreferredOrders[i - 1]];
                uint256 bal = strategy.balanceOf(address(this));
                if (bal > 0) {
                    strategy.withdraw(address(this), (bal > _amount) ? _amount : bal);
                    _token.transferFrom(address(strategy), valueVaultMaster.bank(), _token.balanceOf(address(strategy)));
                    if (_token.balanceOf(valueVaultMaster.bank()) >= _amount) break;
                }
            }
        }
    }

    function harvestAllStrategies(uint256 _bankPoolId) external {
        require(_msgSender() == valueVaultMaster.bank(), "not bank");
        for (uint256 i = 0; i < strategies.length; ++i) {
            strategies[i].harvest(_bankPoolId);
        }
    }

    function harvestStrategy(IStrategy _strategy, uint256 _bankPoolId) external {
        require(_msgSender() == valueVaultMaster.bank(), "not bank");
        _strategy.harvest(_bankPoolId);
    }

    function withdrawStrategy(IStrategy _strategy, uint256 amount) external {
        require(msg.sender == governance, "!governance");
        _strategy.withdraw(address(this), amount);
    }

    function claimStrategy(IStrategy _strategy) external {
        require(msg.sender == governance, "!governance");
        _strategy.claim(address(this));
    }

    /**
     * This function allows governance to take unsupported tokens out of the contract.
     * This is in an effort to make someone whole, should they seriously mess up.
     * There is no guarantee governance will vote to return these.
     * It also allows for removal of airdropped tokens.
     */
    function governanceRecoverUnsupported(IERC20 _token, uint256 amount, address to) external {
        require(msg.sender == governance, "!governance");
        _token.transfer(to, amount);
    }
}

// File: contracts/vaults/vaults/WETHVault.sol

contract WETHVault is ValueVault {
    constructor (
        ValueVaultMaster _master,
        IStrategy _wethStrategy
    ) ValueVault(_master, "Value Vaults: WETH", "vWETH") public  {
        IStrategy[] memory strategies = new IStrategy[](1);
        strategies[0] = _wethStrategy;
        setStrategies(strategies);
    }
}