// File: contracts/APYGovernanceToken.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts-ethereum-package/contracts/access/Ownable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol";

contract APYGovernanceToken is
    Initializable,
    OwnableUpgradeSafe,
    ERC20UpgradeSafe
{
    /* ------------------------------- */
    /* impl-specific storage variables */
    /* ------------------------------- */
    address public proxyAdmin;

    /* ------------------------------- */

    event AdminChanged(address);

    function initialize(address adminAddress, uint256 totalSupply)
        external
        initializer
    {
        require(adminAddress != address(0), "INVALID_ADMIN");

        // initialize ancestor storage
        __Context_init_unchained();
        __Ownable_init_unchained();
        __ERC20_init_unchained("APY Governance Token", "APY");

        // initialize impl-specific storage
        setAdminAddress(adminAddress);

        _mint(msg.sender, totalSupply);
    }

    // solhint-disable-next-line no-empty-blocks
    function initializeUpgrade() external virtual onlyAdmin {}

    function setAdminAddress(address adminAddress) public onlyOwner {
        require(adminAddress != address(0), "INVALID_ADMIN");
        proxyAdmin = adminAddress;
        emit AdminChanged(adminAddress);
    }

    modifier onlyAdmin() {
        require(msg.sender == proxyAdmin, "ADMIN_ONLY");
        _;
    }

    receive() external payable {
        revert("DONT_SEND_ETHER");
    }
}

// File: @openzeppelin/contracts-ethereum-package/contracts/access/Ownable.sol



pragma solidity ^0.6.0;

import "../GSN/Context.sol";
import "../Initializable.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract OwnableUpgradeSafe is Initializable, ContextUpgradeSafe {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */

    function __Ownable_init() internal initializer {
        __Context_init_unchained();
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal initializer {


        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);

    }


    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }

    uint256[49] private __gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/GSN/Context.sol



pragma solidity ^0.6.0;
import "../Initializable.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.
 */
contract ContextUpgradeSafe is Initializable {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.

    function __Context_init() internal initializer {
        __Context_init_unchained();
    }

    function __Context_init_unchained() internal initializer {


    }


    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;
    }

    uint256[50] private __gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/Initializable.sol



pragma solidity >=0.4.24 <0.7.0;


/**
 * @title Initializable
 *
 * @dev Helper contract to support initializer functions. To use it, replace
 * the constructor with a function that has the `initializer` modifier.
 * WARNING: Unlike constructors, initializer functions must be manually
 * invoked. This applies both to deploying an Initializable contract, as well
 * as extending an Initializable contract via inheritance.
 * WARNING: When used with inheritance, manual care must be taken to not invoke
 * a parent initializer twice, or ensure that all initializers are idempotent,
 * because this is not dealt with automatically as with constructors.
 */
contract Initializable {

  /**
   * @dev Indicates that the contract has been initialized.
   */
  bool private initialized;

  /**
   * @dev Indicates that the contract is in the process of being initialized.
   */
  bool private initializing;

  /**
   * @dev Modifier to use in the initializer function of a contract.
   */
  modifier initializer() {
    require(initializing || isConstructor() || !initialized, "Contract instance has already been initialized");

    bool isTopLevelCall = !initializing;
    if (isTopLevelCall) {
      initializing = true;
      initialized = true;
    }

    _;

    if (isTopLevelCall) {
      initializing = false;
    }
  }

  /// @dev Returns true if and only if the function is running in the constructor
  function isConstructor() private view returns (bool) {
    // extcodesize checks the size of the code stored in an address, and
    // address returns the current address. Since the code is still not
    // deployed when running a constructor, any checks on its code size will
    // yield zero, making it an effective way to detect if a contract is
    // under construction or not.
    address self = address(this);
    uint256 cs;
    assembly { cs := extcodesize(self) }
    return cs == 0;
  }

  // Reserved storage space to allow for layout changes in the future.
  uint256[50] private ______gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol



pragma solidity ^0.6.0;

import "../../GSN/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";
import "../../Initializable.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 {ERC20MinterPauser}.
 *
 * 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 ERC20UpgradeSafe is Initializable, ContextUpgradeSafe, 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.
     */

    function __ERC20_init(string memory name, string memory symbol) internal initializer {
        __Context_init_unchained();
        __ERC20_init_unchained(name, symbol);
    }

    function __ERC20_init_unchained(string memory name, string memory symbol) internal initializer {


        _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 is 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 { }

    uint256[44] private __gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol



pragma solidity ^0.6.0;

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol



pragma solidity ^0.6.0;

/**
 * @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.
     */
    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) {
        // 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.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts-ethereum-package/contracts/utils/Address.sol



pragma solidity ^0.6.2;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

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

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: contracts/APYGovernanceTokenProxy.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/proxy/TransparentUpgradeableProxy.sol";

contract APYGovernanceTokenProxy is TransparentUpgradeableProxy {
    constructor(
        address _logic,
        address _proxyAdmin,
        uint256 _totalSupply
    )
        public
        TransparentUpgradeableProxy(
            _logic,
            _proxyAdmin,
            abi.encodeWithSignature(
                "initialize(address,uint256)",
                _proxyAdmin,
                _totalSupply
            )
        )
    {} // solhint-disable no-empty-blocks
}

// File: @openzeppelin/contracts/proxy/TransparentUpgradeableProxy.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import "./UpgradeableProxy.sol";

/**
 * @dev This contract implements a proxy that is upgradeable by an admin.
 * 
 * To avoid https://medium.com/nomic-labs-blog/malicious-backdoors-in-ethereum-proxies-62629adf3357[proxy selector
 * clashing], which can potentially be used in an attack, this contract uses the
 * https://blog.openzeppelin.com/the-transparent-proxy-pattern/[transparent proxy pattern]. This pattern implies two
 * things that go hand in hand:
 * 
 * 1. If any account other than the admin calls the proxy, the call will be forwarded to the implementation, even if
 * that call matches one of the admin functions exposed by the proxy itself.
 * 2. If the admin calls the proxy, it can access the admin functions, but its calls will never be forwarded to the
 * implementation. If the admin tries to call a function on the implementation it will fail with an error that says
 * "admin cannot fallback to proxy target".
 * 
 * These properties mean that the admin account can only be used for admin actions like upgrading the proxy or changing
 * the admin, so it's best if it's a dedicated account that is not used for anything else. This will avoid headaches due
 * to sudden errors when trying to call a function from the proxy implementation.
 * 
 * Our recommendation is for the dedicated account to be an instance of the {ProxyAdmin} contract. If set up this way,
 * you should think of the `ProxyAdmin` instance as the real administrative inerface of your proxy.
 */
contract TransparentUpgradeableProxy is UpgradeableProxy {
    /**
     * @dev Initializes an upgradeable proxy managed by `_admin`, backed by the implementation at `_logic`, and
     * optionally initialized with `_data` as explained in {UpgradeableProxy-constructor}.
     */
    constructor(address _logic, address _admin, bytes memory _data) public payable UpgradeableProxy(_logic, _data) {
        assert(_ADMIN_SLOT == bytes32(uint256(keccak256("eip1967.proxy.admin")) - 1));
        _setAdmin(_admin);
    }

    /**
     * @dev Emitted when the admin account has changed.
     */
    event AdminChanged(address previousAdmin, address newAdmin);

    /**
     * @dev Storage slot with the admin of the contract.
     * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 private constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

    /**
     * @dev Modifier used internally that will delegate the call to the implementation unless the sender is the admin.
     */
    modifier ifAdmin() {
        if (msg.sender == _admin()) {
            _;
        } else {
            _fallback();
        }
    }

    /**
     * @dev Returns the current admin.
     * 
     * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyAdmin}.
     * 
     * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
     * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
     * `0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103`
     */
    function admin() external ifAdmin returns (address) {
        return _admin();
    }

    /**
     * @dev Returns the current implementation.
     * 
     * NOTE: Only the admin can call this function. See {ProxyAdmin-getProxyImplementation}.
     * 
     * TIP: To get this value clients can read directly from the storage slot shown below (specified by EIP1967) using the
     * https://eth.wiki/json-rpc/API#eth_getstorageat[`eth_getStorageAt`] RPC call.
     * `0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc`
     */
    function implementation() external ifAdmin returns (address) {
        return _implementation();
    }

    /**
     * @dev Changes the admin of the proxy.
     * 
     * Emits an {AdminChanged} event.
     * 
     * NOTE: Only the admin can call this function. See {ProxyAdmin-changeProxyAdmin}.
     */
    function changeAdmin(address newAdmin) external ifAdmin {
        require(newAdmin != address(0), "TransparentUpgradeableProxy: new admin is the zero address");
        emit AdminChanged(_admin(), newAdmin);
        _setAdmin(newAdmin);
    }

    /**
     * @dev Upgrade the implementation of the proxy.
     * 
     * NOTE: Only the admin can call this function. See {ProxyAdmin-upgrade}.
     */
    function upgradeTo(address newImplementation) external ifAdmin {
        _upgradeTo(newImplementation);
    }

    /**
     * @dev Upgrade the implementation of the proxy, and then call a function from the new implementation as specified
     * by `data`, which should be an encoded function call. This is useful to initialize new storage variables in the
     * proxied contract.
     * 
     * NOTE: Only the admin can call this function. See {ProxyAdmin-upgradeAndCall}.
     */
    function upgradeToAndCall(address newImplementation, bytes calldata data) external payable ifAdmin {
        _upgradeTo(newImplementation);
        // solhint-disable-next-line avoid-low-level-calls
        (bool success,) = newImplementation.delegatecall(data);
        require(success);
    }

    /**
     * @dev Returns the current admin.
     */
    function _admin() internal view returns (address adm) {
        bytes32 slot = _ADMIN_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            adm := sload(slot)
        }
    }

    /**
     * @dev Stores a new address in the EIP1967 admin slot.
     */
    function _setAdmin(address newAdmin) private {
        bytes32 slot = _ADMIN_SLOT;

        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, newAdmin)
        }
    }

    /**
     * @dev Makes sure the admin cannot access the fallback function. See {Proxy-_beforeFallback}.
     */
    function _beforeFallback() internal override virtual {
        require(msg.sender != _admin(), "TransparentUpgradeableProxy: admin cannot fallback to proxy target");
        super._beforeFallback();
    }
}

// File: @openzeppelin/contracts/proxy/UpgradeableProxy.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

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

/**
 * @dev This contract implements an upgradeable proxy. It is upgradeable because calls are delegated to an
 * implementation address that can be changed. This address is stored in storage in the location specified by
 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967], so that it doesn't conflict with the storage layout of the
 * implementation behind the proxy.
 * 
 * Upgradeability is only provided internally through {_upgradeTo}. For an externally upgradeable proxy see
 * {TransparentUpgradeableProxy}.
 */
contract UpgradeableProxy is Proxy {
    /**
     * @dev Initializes the upgradeable proxy with an initial implementation specified by `_logic`.
     * 
     * If `_data` is nonempty, it's used as data in a delegate call to `_logic`. This will typically be an encoded
     * function call, and allows initializating the storage of the proxy like a Solidity constructor.
     */
    constructor(address _logic, bytes memory _data) public payable {
        assert(_IMPLEMENTATION_SLOT == bytes32(uint256(keccak256("eip1967.proxy.implementation")) - 1));
        _setImplementation(_logic);
        if(_data.length > 0) {
            // solhint-disable-next-line avoid-low-level-calls
            (bool success,) = _logic.delegatecall(_data);
            require(success);
        }
    }

    /**
     * @dev Emitted when the implementation is upgraded.
     */
    event Upgraded(address indexed implementation);

    /**
     * @dev Storage slot with the address of the current implementation.
     * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
     * validated in the constructor.
     */
    bytes32 private constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /**
     * @dev Returns the current implementation address.
     */
    function _implementation() internal override view returns (address impl) {
        bytes32 slot = _IMPLEMENTATION_SLOT;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            impl := sload(slot)
        }
    }

    /**
     * @dev Upgrades the proxy to a new implementation.
     * 
     * Emits an {Upgraded} event.
     */
    function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

    /**
     * @dev Stores a new address in the EIP1967 implementation slot.
     */
    function _setImplementation(address newImplementation) private {
        require(Address.isContract(newImplementation), "UpgradeableProxy: new implementation is not a contract");

        bytes32 slot = _IMPLEMENTATION_SLOT;

        // solhint-disable-next-line no-inline-assembly
        assembly {
            sstore(slot, newImplementation)
        }
    }
}

// File: @openzeppelin/contracts/proxy/Proxy.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @dev This abstract contract provides a fallback function that delegates all calls to another contract using the EVM
 * instruction `delegatecall`. We refer to the second contract as the _implementation_ behind the proxy, and it has to
 * be specified by overriding the virtual {_implementation} function.
 * 
 * Additionally, delegation to the implementation can be triggered manually through the {_fallback} function, or to a
 * different contract through the {_delegate} function.
 * 
 * The success and return data of the delegated call will be returned back to the caller of the proxy.
 */
abstract contract Proxy {
    /**
     * @dev Delegates the current call to `implementation`.
     * 
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _delegate(address implementation) internal {
        // solhint-disable-next-line no-inline-assembly
        assembly {
            // Copy msg.data. We take full control of memory in this inline assembly
            // block because it will not return to Solidity code. We overwrite the
            // Solidity scratch pad at memory position 0.
            calldatacopy(0, 0, calldatasize())

            // Call the implementation.
            // out and outsize are 0 because we don't know the size yet.
            let result := delegatecall(gas(), implementation, 0, calldatasize(), 0, 0)

            // Copy the returned data.
            returndatacopy(0, 0, returndatasize())

            switch result
            // delegatecall returns 0 on error.
            case 0 { revert(0, returndatasize()) }
            default { return(0, returndatasize()) }
        }
    }

    /**
     * @dev This is a virtual function that should be overriden so it returns the address to which the fallback function
     * and {_fallback} should delegate.
     */
    function _implementation() internal virtual view returns (address);

    /**
     * @dev Delegates the current call to the address returned by `_implementation()`.
     * 
     * This function does not return to its internall call site, it will return directly to the external caller.
     */
    function _fallback() internal {
        _beforeFallback();
        _delegate(_implementation());
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if no other
     * function in the contract matches the call data.
     */
    fallback () payable external {
        _fallback();
    }

    /**
     * @dev Fallback function that delegates calls to the address returned by `_implementation()`. Will run if call data
     * is empty.
     */
    receive () payable external {
        _fallback();
    }

    /**
     * @dev Hook that is called before falling back to the implementation. Can happen as part of a manual `_fallback`
     * call, or as part of the Solidity `fallback` or `receive` functions.
     * 
     * If overriden should call `super._beforeFallback()`.
     */
    function _beforeFallback() internal virtual {
    }
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.2;

/**
 * @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: contracts/APYGovernanceTokenUpgraded.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;
pragma experimental ABIEncoderV2;

import "./APYGovernanceToken.sol";

contract APYGovernanceTokenUpgraded is APYGovernanceToken {
    bool public newlyAddedVariable;

    function initializeUpgrade() public override onlyAdmin {
        newlyAddedVariable = true;
    }
}

// File: contracts/APYPoolToken.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts-ethereum-package/contracts/access/Ownable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/utils/ReentrancyGuard.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/utils/Pausable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol";
import "./interfaces/ILiquidityPool.sol";

contract APYPoolToken is
    ILiquidityPool,
    Initializable,
    OwnableUpgradeSafe,
    ReentrancyGuardUpgradeSafe,
    PausableUpgradeSafe,
    ERC20UpgradeSafe
{
    using SafeMath for uint256;
    using SafeERC20 for IERC20;
    uint256 public constant DEFAULT_APT_TO_UNDERLYER_FACTOR = 1000;

    /* ------------------------------- */
    /* impl-specific storage variables */
    /* ------------------------------- */
    address public proxyAdmin;
    bool public addLiquidityLock;
    bool public redeemLock;
    IERC20 public underlyer;
    AggregatorV3Interface public priceAgg;

    /* ------------------------------- */

    function initialize(
        address adminAddress,
        IERC20 _underlyer,
        AggregatorV3Interface _priceAgg
    ) external initializer {
        require(adminAddress != address(0), "INVALID_ADMIN");
        require(address(_underlyer) != address(0), "INVALID_TOKEN");
        require(address(_priceAgg) != address(0), "INVALID_AGG");

        // initialize ancestor storage
        __Context_init_unchained();
        __Ownable_init_unchained();
        __ReentrancyGuard_init_unchained();
        __Pausable_init_unchained();
        __ERC20_init_unchained("APY Pool Token", "APT");

        // initialize impl-specific storage
        setAdminAddress(adminAddress);
        addLiquidityLock = false;
        redeemLock = false;
        underlyer = _underlyer;
        setPriceAggregator(_priceAgg);
    }

    // solhint-disable-next-line no-empty-blocks
    function initializeUpgrade() external virtual onlyAdmin {}

    function setAdminAddress(address adminAddress) public onlyOwner {
        require(adminAddress != address(0), "INVALID_ADMIN");
        proxyAdmin = adminAddress;
        emit AdminChanged(adminAddress);
    }

    function setPriceAggregator(AggregatorV3Interface _priceAgg)
        public
        onlyOwner
    {
        require(address(_priceAgg) != address(0), "INVALID_AGG");
        priceAgg = _priceAgg;
        emit PriceAggregatorChanged(address(_priceAgg));
    }

    modifier onlyAdmin() {
        require(msg.sender == proxyAdmin, "ADMIN_ONLY");
        _;
    }

    function lock() external onlyOwner {
        _pause();
    }

    function unlock() external onlyOwner {
        _unpause();
    }

    receive() external payable {
        revert("DONT_SEND_ETHER");
    }

    /**
     * @notice Mint corresponding amount of APT tokens for sent token amount.
     * @dev If no APT tokens have been minted yet, fallback to a fixed ratio.
     */
    function addLiquidity(uint256 tokenAmt)
        external
        override
        nonReentrant
        whenNotPaused
    {
        require(!addLiquidityLock, "LOCKED");
        require(tokenAmt > 0, "AMOUNT_INSUFFICIENT");
        require(
            underlyer.allowance(msg.sender, address(this)) >= tokenAmt,
            "ALLOWANCE_INSUFFICIENT"
        );

        // NOTE: calculateMintAmount() is not used to save gas
        uint256 depositEthValue = getEthValueFromTokenAmount(tokenAmt);
        uint256 poolTotalEthValue = getPoolTotalEthValue();

        uint256 mintAmount = _calculateMintAmount(
            depositEthValue,
            poolTotalEthValue
        );

        _mint(msg.sender, mintAmount);
        underlyer.safeTransferFrom(msg.sender, address(this), tokenAmt);

        emit DepositedAPT(
            msg.sender,
            underlyer,
            tokenAmt,
            mintAmount,
            depositEthValue,
            getPoolTotalEthValue()
        );
    }

    function getPoolTotalEthValue() public view returns (uint256) {
        return getEthValueFromTokenAmount(underlyer.balanceOf(address(this)));
    }

    function getAPTEthValue(uint256 amount) public view returns (uint256) {
        require(totalSupply() > 0, "INSUFFICIENT_TOTAL_SUPPLY");
        return (amount.mul(getPoolTotalEthValue())).div(totalSupply());
    }

    function getEthValueFromTokenAmount(uint256 amount)
        public
        view
        returns (uint256)
    {
        if (amount == 0) {
            return 0;
        }
        uint256 decimals = ERC20UpgradeSafe(address(underlyer)).decimals();
        // ethValue = (tokenEthPrice * amount) / decimals
        return ((getTokenEthPrice()).mul(amount)).div(10**decimals);
    }

    function getTokenAmountFromEthValue(uint256 ethValue)
        public
        view
        returns (uint256)
    {
        uint256 tokenEthPrice = getTokenEthPrice();
        uint256 decimals = ERC20UpgradeSafe(address(underlyer)).decimals();
        // amount = (ethValue * decimals) / tokenEthPrice
        return ((10**decimals).mul(ethValue)).div(tokenEthPrice); //tokenAmount
    }

    function getTokenEthPrice() public view returns (uint256) {
        (, int256 price, , , ) = priceAgg.latestRoundData();
        require(price > 0, "UNABLE_TO_RETRIEVE_ETH_PRICE");
        return uint256(price);
    }

    function lockAddLiquidity() external onlyOwner {
        addLiquidityLock = true;
        emit AddLiquidityLocked();
    }

    function unlockAddLiquidity() external onlyOwner {
        addLiquidityLock = false;
        emit AddLiquidityUnlocked();
    }

    /**
     * @notice Redeems APT amount for its underlying token amount.
     * @param aptAmount The amount of APT tokens to redeem
     */
    function redeem(uint256 aptAmount)
        external
        override
        nonReentrant
        whenNotPaused
    {
        require(!redeemLock, "LOCKED");
        require(aptAmount > 0, "AMOUNT_INSUFFICIENT");
        require(aptAmount <= balanceOf(msg.sender), "BALANCE_INSUFFICIENT");

        uint256 redeemTokenAmt = getUnderlyerAmount(aptAmount);

        _burn(msg.sender, aptAmount);
        underlyer.safeTransfer(msg.sender, redeemTokenAmt);

        emit RedeemedAPT(
            msg.sender,
            underlyer,
            redeemTokenAmt,
            aptAmount,
            getEthValueFromTokenAmount(redeemTokenAmt),
            getPoolTotalEthValue()
        );
    }

    function lockRedeem() external onlyOwner {
        redeemLock = true;
        emit RedeemLocked();
    }

    function unlockRedeem() external onlyOwner {
        redeemLock = false;
        emit RedeemUnlocked();
    }

    function calculateMintAmount(uint256 tokenAmt)
        public
        view
        returns (uint256)
    {
        uint256 depositEthValue = getEthValueFromTokenAmount(tokenAmt);
        uint256 poolTotalEthValue = getPoolTotalEthValue();
        return _calculateMintAmount(depositEthValue, poolTotalEthValue); // amount of APT
    }

    /**
     *  @notice amount of APT minted should be in same ratio to APT supply
     *          as token amount sent is to contract's token balance, i.e.:
     *
     *          mint amount / total supply (before deposit)
     *          = token amount sent / contract token balance (before deposit)
     */
    function _calculateMintAmount(
        uint256 depositEthAmount,
        uint256 totalEthAmount
    ) internal view returns (uint256) {
        // NOTE: When totalSupply > 0 && totalEthAmount == 0
        // others can lay claim to other users deposits

        uint256 totalSupply = totalSupply();

        if (totalEthAmount == 0 || totalSupply == 0) {
            return depositEthAmount.mul(DEFAULT_APT_TO_UNDERLYER_FACTOR);
        }

        return (depositEthAmount.mul(totalSupply)).div(totalEthAmount);
    }

    /**
     * @notice Get the underlying amount represented by APT amount.
     * @param aptAmount The amount of APT tokens
     * @return uint256 The underlying value of the APT tokens
     */
    function getUnderlyerAmount(uint256 aptAmount)
        public
        view
        returns (uint256)
    {
        return getTokenAmountFromEthValue(getAPTEthValue(aptAmount));
    }
}

/**
 * @dev Proxy contract to test internal variables and functions
 *      Should not be used other than in test files!
 */
contract APYPoolTokenTEST is APYPoolToken {
    function mint(address account, uint256 amount) public {
        _mint(account, amount);
    }

    function burn(address account, uint256 amount) public {
        _burn(account, amount);
    }
}

// File: @openzeppelin/contracts-ethereum-package/contracts/utils/ReentrancyGuard.sol



pragma solidity ^0.6.0;
import "../Initializable.sol";

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
contract ReentrancyGuardUpgradeSafe is Initializable {
    bool private _notEntered;


    function __ReentrancyGuard_init() internal initializer {
        __ReentrancyGuard_init_unchained();
    }

    function __ReentrancyGuard_init_unchained() internal initializer {


        // Storing an initial non-zero value makes deployment a bit more
        // expensive, but in exchange the refund on every call to nonReentrant
        // will be lower in amount. Since refunds are capped to a percetange of
        // the total transaction's gas, it is best to keep them low in cases
        // like this one, to increase the likelihood of the full refund coming
        // into effect.
        _notEntered = true;

    }


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

        // Any calls to nonReentrant after this point will fail
        _notEntered = false;

        _;

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

    uint256[49] private __gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/utils/Pausable.sol



pragma solidity ^0.6.0;

import "../GSN/Context.sol";
import "../Initializable.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
contract PausableUpgradeSafe is Initializable, ContextUpgradeSafe {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */

    function __Pausable_init() internal initializer {
        __Context_init_unchained();
        __Pausable_init_unchained();
    }

    function __Pausable_init_unchained() internal initializer {


        _paused = false;

    }


    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     */
    modifier whenNotPaused() {
        require(!_paused, "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     */
    modifier whenPaused() {
        require(_paused, "Pausable: not paused");
        _;
    }

    /**
     * @dev Triggers stopped state.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }

    uint256[49] private __gap;
}

// File: @openzeppelin/contracts-ethereum-package/contracts/token/ERC20/SafeERC20.sol



pragma solidity ^0.6.0;

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

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for 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: @chainlink/contracts/src/v0.6/interfaces/AggregatorV3Interface.sol



pragma solidity >=0.6.0;

interface AggregatorV3Interface {

  function decimals() external view returns (uint8);
  function description() external view returns (string memory);
  function version() external view returns (uint256);

  // getRoundData and latestRoundData should both raise "No data present"
  // if they do not have data to report, instead of returning unset values
  // which could be misinterpreted as actual reported values.
  function getRoundData(uint80 _roundId)
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );
  function latestRoundData()
    external
    view
    returns (
      uint80 roundId,
      int256 answer,
      uint256 startedAt,
      uint256 updatedAt,
      uint80 answeredInRound
    );

}

// File: contracts/interfaces/ILiquidityPool.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol";

interface ILiquidityPool {
    event DepositedAPT(
        address indexed sender,
        IERC20 token,
        uint256 tokenAmount,
        uint256 aptMintAmount,
        uint256 tokenEthValue,
        uint256 totalEthValueLocked
    );
    event RedeemedAPT(
        address indexed sender,
        IERC20 token,
        uint256 redeemedTokenAmount,
        uint256 aptRedeemAmount,
        uint256 tokenEthValue,
        uint256 totalEthValueLocked
    );
    event AddLiquidityLocked();
    event AddLiquidityUnlocked();
    event RedeemLocked();
    event RedeemUnlocked();
    event AdminChanged(address);
    event PriceAggregatorChanged(address agg);

    function addLiquidity(uint256 amount) external;

    function redeem(uint256 tokenAmount) external;
}

// File: contracts/APYPoolTokenUpgraded.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;
pragma experimental ABIEncoderV2;

import "./APYPoolToken.sol";

contract APYPoolTokenUpgraded is APYPoolToken {
    bool public newlyAddedVariable;

    function initializeUpgrade() public override onlyAdmin {
        newlyAddedVariable = true;
    }
}

// File: contracts/APYRewardDistributor.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts/cryptography/ECDSA.sol";
import "@openzeppelin/contracts/access/Ownable.sol";

contract APYRewardDistributor is Ownable {
    using ECDSA for bytes32;
    using SafeERC20 for IERC20;

    event SignerSet(address newSigner);
    event Claimed(uint256 nonce, address recipient, uint256 amount);

    struct EIP712Domain {
        string name;
        string version;
        uint256 chainId;
        address verifyingContract;
    }

    struct Recipient {
        uint256 nonce;
        address wallet;
        uint256 amount;
    }

    bytes32 private constant EIP712_DOMAIN_TYPEHASH = keccak256(
        "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
    );

    bytes32 private constant RECIPIENT_TYPEHASH = keccak256(
        "Recipient(uint256 nonce,address wallet,uint256 amount)"
    );

    bytes32 private immutable DOMAIN_SEPARATOR;

    IERC20 public immutable apyToken;
    mapping(address => uint256) public accountNonces;
    address public signer;

    constructor(IERC20 token, address signerAddress) public {
        require(address(token) != address(0), "Invalid APY Address");
        require(signerAddress != address(0), "Invalid Signer Address");
        apyToken = token;
        signer = signerAddress;

        DOMAIN_SEPARATOR = _hashDomain(
            EIP712Domain({
                name: "APY Distribution",
                version: "1",
                chainId: _getChainID(),
                verifyingContract: address(this)
            })
        );
    }

    function _hashDomain(EIP712Domain memory eip712Domain)
        private
        pure
        returns (bytes32)
    {
        return
            keccak256(
                abi.encode(
                    EIP712_DOMAIN_TYPEHASH,
                    keccak256(bytes(eip712Domain.name)),
                    keccak256(bytes(eip712Domain.version)),
                    eip712Domain.chainId,
                    eip712Domain.verifyingContract
                )
            );
    }

    function _hashRecipient(Recipient memory recipient)
        private
        pure
        returns (bytes32)
    {
        return
            keccak256(
                abi.encode(
                    RECIPIENT_TYPEHASH,
                    recipient.nonce,
                    recipient.wallet,
                    recipient.amount
                )
            );
    }

    function _hash(Recipient memory recipient) private returns (bytes32) {
        return
            keccak256(
                abi.encodePacked(
                    "\x19\x01",
                    DOMAIN_SEPARATOR,
                    _hashRecipient(recipient)
                )
            );
    }

    function _getChainID() private view returns (uint256) {
        uint256 id;
        // no-inline-assembly
        assembly {
            id := chainid()
        }
        return id;
    }

    function setSigner(address newSigner) external onlyOwner {
        signer = newSigner;
    }

    function claim(
        Recipient calldata recipient,
        uint8 v,
        bytes32 r,
        bytes32 s // bytes calldata signature
    ) external {
        address signatureSigner = ecrecover(_hash(recipient), v, r, s);
        require(signatureSigner == signer, "Invalid Signature");

        require(
            recipient.nonce == accountNonces[recipient.wallet],
            "Nonce Mismatch"
        );
        require(
            apyToken.balanceOf(address(this)) >= recipient.amount,
            "Insufficient Funds"
        );

        accountNonces[recipient.wallet] += 1;
        apyToken.safeTransfer(recipient.wallet, recipient.amount);

        emit Claimed(recipient.nonce, recipient.wallet, recipient.amount);
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

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

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/math/SafeMath.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @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.
     */
    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/cryptography/ECDSA.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        // Check the signature length
        if (signature.length != 65) {
            revert("ECDSA: invalid signature length");
        }

        // Divide the signature in r, s and v variables
        bytes32 r;
        bytes32 s;
        uint8 v;

        // ecrecover takes the signature parameters, and the only way to get them
        // currently is to use assembly.
        // solhint-disable-next-line no-inline-assembly
        assembly {
            r := mload(add(signature, 0x20))
            s := mload(add(signature, 0x40))
            v := byte(0, mload(add(signature, 0x60)))
        }

        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (281): 0 < s < secp256k1n ÷ 2 + 1, and for v in (282): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            revert("ECDSA: invalid signature 's' value");
        }

        if (v != 27 && v != 28) {
            revert("ECDSA: invalid signature 'v' value");
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        require(signer != address(0), "ECDSA: invalid signature");

        return signer;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * replicates the behavior of the
     * https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_sign[`eth_sign`]
     * JSON-RPC method.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import "../GSN/Context.sol";
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: @openzeppelin/contracts/GSN/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with 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: contracts/Imports.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;

// We import the contract so truffle compiles it, and we have the ABI
// available when working from truffle console.
import "@gnosis.pm/mock-contract/contracts/MockContract.sol";
import "@openzeppelin/contracts/proxy/ProxyAdmin.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol"; //helpers
import "./interfaces/IMintableERC20.sol";

// File: @gnosis.pm/mock-contract/contracts/MockContract.sol



pragma solidity ^0.6.0;

interface MockInterface {
	/**
	 * @dev After calling this method, the mock will return `response` when it is called
	 * with any calldata that is not mocked more specifically below
	 * (e.g. using givenMethodReturn).
	 * @param response ABI encoded response that will be returned if method is invoked
	 */
	function givenAnyReturn(bytes calldata response) external;
	function givenAnyReturnBool(bool response) external;
	function givenAnyReturnUint(uint response) external;
	function givenAnyReturnAddress(address response) external;

	function givenAnyRevert() external;
	function givenAnyRevertWithMessage(string calldata message) external;
	function givenAnyRunOutOfGas() external;

	/**
	 * @dev After calling this method, the mock will return `response` when the given
	 * methodId is called regardless of arguments. If the methodId and arguments
	 * are mocked more specifically (using `givenMethodAndArguments`) the latter
	 * will take precedence.
	 * @param method ABI encoded methodId. It is valid to pass full calldata (including arguments). The mock will extract the methodId from it
	 * @param response ABI encoded response that will be returned if method is invoked
	 */
	function givenMethodReturn(bytes calldata method, bytes calldata response) external;
	function givenMethodReturnBool(bytes calldata method, bool response) external;
	function givenMethodReturnUint(bytes calldata method, uint response) external;
	function givenMethodReturnAddress(bytes calldata method, address response) external;

	function givenMethodRevert(bytes calldata method) external;
	function givenMethodRevertWithMessage(bytes calldata method, string calldata message) external;
	function givenMethodRunOutOfGas(bytes calldata method) external;

	/**
	 * @dev After calling this method, the mock will return `response` when the given
	 * methodId is called with matching arguments. These exact calldataMocks will take
	 * precedence over all other calldataMocks.
	 * @param call ABI encoded calldata (methodId and arguments)
	 * @param response ABI encoded response that will be returned if contract is invoked with calldata
	 */
	function givenCalldataReturn(bytes calldata call, bytes calldata response) external;
	function givenCalldataReturnBool(bytes calldata call, bool response) external;
	function givenCalldataReturnUint(bytes calldata call, uint response) external;
	function givenCalldataReturnAddress(bytes calldata call, address response) external;

	function givenCalldataRevert(bytes calldata call) external;
	function givenCalldataRevertWithMessage(bytes calldata call, string calldata message) external;
	function givenCalldataRunOutOfGas(bytes calldata call) external;

	/**
	 * @dev Returns the number of times anything has been called on this mock since last reset
	 */
	function invocationCount() external returns (uint);

	/**
	 * @dev Returns the number of times the given method has been called on this mock since last reset
	 * @param method ABI encoded methodId. It is valid to pass full calldata (including arguments). The mock will extract the methodId from it
	 */
	function invocationCountForMethod(bytes calldata method) external returns (uint);

	/**
	 * @dev Returns the number of times this mock has been called with the exact calldata since last reset.
	 * @param call ABI encoded calldata (methodId and arguments)
	 */
	function invocationCountForCalldata(bytes calldata call) external returns (uint);

	/**
	 * @dev Resets all mocked methods and invocation counts.
	 */
	 function reset() external;
}

/**
 * Implementation of the MockInterface.
 */
contract MockContract is MockInterface {
	enum MockType { Return, Revert, OutOfGas }
	
	bytes32 public constant MOCKS_LIST_START = hex"01";
	bytes public constant MOCKS_LIST_END = "0xff";
	bytes32 public constant MOCKS_LIST_END_HASH = keccak256(MOCKS_LIST_END);
	bytes4 public constant SENTINEL_ANY_MOCKS = hex"01";
	bytes public constant DEFAULT_FALLBACK_VALUE = abi.encode(false);

	// A linked list allows easy iteration and inclusion checks
	mapping(bytes32 => bytes) calldataMocks;
	mapping(bytes => MockType) calldataMockTypes;
	mapping(bytes => bytes) calldataExpectations;
	mapping(bytes => string) calldataRevertMessage;
	mapping(bytes32 => uint) calldataInvocations;

	mapping(bytes4 => bytes4) methodIdMocks;
	mapping(bytes4 => MockType) methodIdMockTypes;
	mapping(bytes4 => bytes) methodIdExpectations;
	mapping(bytes4 => string) methodIdRevertMessages;
	mapping(bytes32 => uint) methodIdInvocations;

	MockType fallbackMockType;
	bytes fallbackExpectation = DEFAULT_FALLBACK_VALUE;
	string fallbackRevertMessage;
	uint invocations;
	uint resetCount;

	constructor() public {
		calldataMocks[MOCKS_LIST_START] = MOCKS_LIST_END;
		methodIdMocks[SENTINEL_ANY_MOCKS] = SENTINEL_ANY_MOCKS;
	}

	function trackCalldataMock(bytes memory call) private {
		bytes32 callHash = keccak256(call);
		if (calldataMocks[callHash].length == 0) {
			calldataMocks[callHash] = calldataMocks[MOCKS_LIST_START];
			calldataMocks[MOCKS_LIST_START] = call;
		}
	}

	function trackMethodIdMock(bytes4 methodId) private {
		if (methodIdMocks[methodId] == 0x0) {
			methodIdMocks[methodId] = methodIdMocks[SENTINEL_ANY_MOCKS];
			methodIdMocks[SENTINEL_ANY_MOCKS] = methodId;
		}
	}

	function _givenAnyReturn(bytes memory response) internal {
		fallbackMockType = MockType.Return;
		fallbackExpectation = response;
	}

	function givenAnyReturn(bytes calldata response) override external {
		_givenAnyReturn(response);
	}

	function givenAnyReturnBool(bool response) override external {
		uint flag = response ? 1 : 0;
		_givenAnyReturn(uintToBytes(flag));
	}

	function givenAnyReturnUint(uint response) override external {
		_givenAnyReturn(uintToBytes(response));	
	}

	function givenAnyReturnAddress(address response) override external {
		_givenAnyReturn(uintToBytes(uint(response)));
	}

	function givenAnyRevert() override external {
		fallbackMockType = MockType.Revert;
		fallbackRevertMessage = "";
	}

	function givenAnyRevertWithMessage(string calldata message) override external {
		fallbackMockType = MockType.Revert;
		fallbackRevertMessage = message;
	}

	function givenAnyRunOutOfGas() override external {
		fallbackMockType = MockType.OutOfGas;
	}

	function _givenCalldataReturn(bytes memory call, bytes memory response) private  {
		calldataMockTypes[call] = MockType.Return;
		calldataExpectations[call] = response;
		trackCalldataMock(call);
	}

	function givenCalldataReturn(bytes calldata call, bytes calldata response) override external  {
		_givenCalldataReturn(call, response);
	}

	function givenCalldataReturnBool(bytes calldata call, bool response) override external {
		uint flag = response ? 1 : 0;
		_givenCalldataReturn(call, uintToBytes(flag));
	}

	function givenCalldataReturnUint(bytes calldata call, uint response) override external {
		_givenCalldataReturn(call, uintToBytes(response));
	}

	function givenCalldataReturnAddress(bytes calldata call, address response) override external {
		_givenCalldataReturn(call, uintToBytes(uint(response)));
	}

	function _givenMethodReturn(bytes memory call, bytes memory response) private {
		bytes4 method = bytesToBytes4(call);
		methodIdMockTypes[method] = MockType.Return;
		methodIdExpectations[method] = response;
		trackMethodIdMock(method);		
	}

	function givenMethodReturn(bytes calldata call, bytes calldata response) override external {
		_givenMethodReturn(call, response);
	}

	function givenMethodReturnBool(bytes calldata call, bool response) override external {
		uint flag = response ? 1 : 0;
		_givenMethodReturn(call, uintToBytes(flag));
	}

	function givenMethodReturnUint(bytes calldata call, uint response) override external {
		_givenMethodReturn(call, uintToBytes(response));
	}

	function givenMethodReturnAddress(bytes calldata call, address response) override external {
		_givenMethodReturn(call, uintToBytes(uint(response)));
	}

	function givenCalldataRevert(bytes calldata call) override external {
		calldataMockTypes[call] = MockType.Revert;
		calldataRevertMessage[call] = "";
		trackCalldataMock(call);
	}

	function givenMethodRevert(bytes calldata call) override external {
		bytes4 method = bytesToBytes4(call);
		methodIdMockTypes[method] = MockType.Revert;
		trackMethodIdMock(method);		
	}

	function givenCalldataRevertWithMessage(bytes calldata call, string calldata message) override external {
		calldataMockTypes[call] = MockType.Revert;
		calldataRevertMessage[call] = message;
		trackCalldataMock(call);
	}

	function givenMethodRevertWithMessage(bytes calldata call, string calldata message) override external {
		bytes4 method = bytesToBytes4(call);
		methodIdMockTypes[method] = MockType.Revert;
		methodIdRevertMessages[method] = message;
		trackMethodIdMock(method);		
	}

	function givenCalldataRunOutOfGas(bytes calldata call) override external {
		calldataMockTypes[call] = MockType.OutOfGas;
		trackCalldataMock(call);
	}

	function givenMethodRunOutOfGas(bytes calldata call) override external {
		bytes4 method = bytesToBytes4(call);
		methodIdMockTypes[method] = MockType.OutOfGas;
		trackMethodIdMock(method);	
	}

	function invocationCount() override external returns (uint) {
		return invocations;
	}

	function invocationCountForMethod(bytes calldata call) override external returns (uint) {
		bytes4 method = bytesToBytes4(call);
		return methodIdInvocations[keccak256(abi.encodePacked(resetCount, method))];
	}

	function invocationCountForCalldata(bytes calldata call) override external returns (uint) {
		return calldataInvocations[keccak256(abi.encodePacked(resetCount, call))];
	}

	function reset() override external {
		// Reset all exact calldataMocks
		bytes memory nextMock = calldataMocks[MOCKS_LIST_START];
		bytes32 mockHash = keccak256(nextMock);
		// We cannot compary bytes
		while(mockHash != MOCKS_LIST_END_HASH) {
			// Reset all mock maps
			calldataMockTypes[nextMock] = MockType.Return;
			calldataExpectations[nextMock] = hex"";
			calldataRevertMessage[nextMock] = "";
			// Set next mock to remove
			nextMock = calldataMocks[mockHash];
			// Remove from linked list
			calldataMocks[mockHash] = "";
			// Update mock hash
			mockHash = keccak256(nextMock);
		}
		// Clear list
		calldataMocks[MOCKS_LIST_START] = MOCKS_LIST_END;

		// Reset all any calldataMocks
		bytes4 nextAnyMock = methodIdMocks[SENTINEL_ANY_MOCKS];
		while(nextAnyMock != SENTINEL_ANY_MOCKS) {
			bytes4 currentAnyMock = nextAnyMock;
			methodIdMockTypes[currentAnyMock] = MockType.Return;
			methodIdExpectations[currentAnyMock] = hex"";
			methodIdRevertMessages[currentAnyMock] = "";
			nextAnyMock = methodIdMocks[currentAnyMock];
			// Remove from linked list
			methodIdMocks[currentAnyMock] = 0x0;
		}
		// Clear list
		methodIdMocks[SENTINEL_ANY_MOCKS] = SENTINEL_ANY_MOCKS;

		fallbackExpectation = DEFAULT_FALLBACK_VALUE;
		fallbackMockType = MockType.Return;
		invocations = 0;
		resetCount += 1;
	}

	function useAllGas() private {
		while(true) {
			bool s;
			assembly {
				//expensive call to EC multiply contract
				s := call(sub(gas(), 2000), 6, 0, 0x0, 0xc0, 0x0, 0x60)
			}
		}
	}

	function bytesToBytes4(bytes memory b) private pure returns (bytes4) {
		bytes4 out;
		for (uint i = 0; i < 4; i++) {
			out |= bytes4(b[i] & 0xFF) >> (i * 8);
		}
		return out;
	}

	function uintToBytes(uint256 x) private pure returns (bytes memory b) {
		b = new bytes(32);
		assembly { mstore(add(b, 32), x) }
	}

	function updateInvocationCount(bytes4 methodId, bytes memory originalMsgData) public {
		require(msg.sender == address(this), "Can only be called from the contract itself");
		invocations += 1;
		methodIdInvocations[keccak256(abi.encodePacked(resetCount, methodId))] += 1;
		calldataInvocations[keccak256(abi.encodePacked(resetCount, originalMsgData))] += 1;
	}

	fallback () payable external {
		bytes4 methodId;
		assembly {
			methodId := calldataload(0)
		}

		// First, check exact matching overrides
		if (calldataMockTypes[msg.data] == MockType.Revert) {
			revert(calldataRevertMessage[msg.data]);
		}
		if (calldataMockTypes[msg.data] == MockType.OutOfGas) {
			useAllGas();
		}
		bytes memory result = calldataExpectations[msg.data];

		// Then check method Id overrides
		if (result.length == 0) {
			if (methodIdMockTypes[methodId] == MockType.Revert) {
				revert(methodIdRevertMessages[methodId]);
			}
			if (methodIdMockTypes[methodId] == MockType.OutOfGas) {
				useAllGas();
			}
			result = methodIdExpectations[methodId];
		}

		// Last, use the fallback override
		if (result.length == 0) {
			if (fallbackMockType == MockType.Revert) {
				revert(fallbackRevertMessage);
			}
			if (fallbackMockType == MockType.OutOfGas) {
				useAllGas();
			}
			result = fallbackExpectation;
		}

		// Record invocation as separate call so we don't rollback in case we are called with STATICCALL
		(, bytes memory r) = address(this).call{gas: 100000}(abi.encodeWithSignature("updateInvocationCount(bytes4,bytes)", methodId, msg.data));
		assert(r.length == 0);
		
		assembly {
			return(add(0x20, result), mload(result))
		}
	}
}

// File: @openzeppelin/contracts/proxy/ProxyAdmin.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import "../access/Ownable.sol";
import "./TransparentUpgradeableProxy.sol";

/**
 * @dev This is an auxiliary contract meant to be assigned as the admin of a {TransparentUpgradeableProxy}. For an
 * explanation of why you would want to use this see the documentation for {TransparentUpgradeableProxy}.
 */
contract ProxyAdmin is Ownable {

    /**
     * @dev Returns the current implementation of `proxy`.
     * 
     * Requirements:
     * 
     * - This contract must be the admin of `proxy`.
     */
    function getProxyImplementation(TransparentUpgradeableProxy proxy) public view returns (address) {
        // We need to manually run the static call since the getter cannot be flagged as view
        // bytes4(keccak256("implementation()")) == 0x5c60da1b
        (bool success, bytes memory returndata) = address(proxy).staticcall(hex"5c60da1b");
        require(success);
        return abi.decode(returndata, (address));
    }

    /**
     * @dev Returns the current admin of `proxy`.
     * 
     * Requirements:
     * 
     * - This contract must be the admin of `proxy`.
     */
    function getProxyAdmin(TransparentUpgradeableProxy proxy) public view returns (address) {
        // We need to manually run the static call since the getter cannot be flagged as view
        // bytes4(keccak256("admin()")) == 0xf851a440
        (bool success, bytes memory returndata) = address(proxy).staticcall(hex"f851a440");
        require(success);
        return abi.decode(returndata, (address));
    }

    /**
     * @dev Changes the admin of `proxy` to `newAdmin`.
     * 
     * Requirements:
     * 
     * - This contract must be the current admin of `proxy`.
     */
    function changeProxyAdmin(TransparentUpgradeableProxy proxy, address newAdmin) public onlyOwner {
        proxy.changeAdmin(newAdmin);
    }

    /**
     * @dev Upgrades `proxy` to `implementation`. See {TransparentUpgradeableProxy-upgradeTo}.
     * 
     * Requirements:
     * 
     * - This contract must be the admin of `proxy`.
     */
    function upgrade(TransparentUpgradeableProxy proxy, address implementation) public onlyOwner {
        proxy.upgradeTo(implementation);
    }

    /**
     * @dev Upgrades `proxy` to `implementation` and calls a function on the new implementation. See
     * {TransparentUpgradeableProxy-upgradeToAndCall}.
     * 
     * Requirements:
     * 
     * - This contract must be the admin of `proxy`.
     */
    function upgradeAndCall(TransparentUpgradeableProxy proxy, address implementation, bytes memory data) public payable onlyOwner {
        proxy.upgradeToAndCall{value: msg.value}(implementation, data);
    }
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import "../../GSN/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.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/interfaces/IMintableERC20.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity 0.6.11;

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

interface IMintableERC20 is IERC20 {
    function mint(address account, uint256 amount) external;

    function name() external view returns (string memory);

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

    function decimals() external view returns (uint8);
}