Contract 0x1f6b96d2e7a5D70777D2A9c52215044FB3f40D37 2

/**
 *Submitted for verification at Etherscan.io on 2021-04-21
*/

/*
   ____            __   __        __   _
  / __/__ __ ___  / /_ / /  ___  / /_ (_)__ __
 _\ \ / // // _ \/ __// _ \/ -_)/ __// / \ \ /
/___/ \_, //_//_/\__//_//_/\__/ \__//_/ /_\_\
     /___/

* Synthetix: VirtualSynthMastercopy.sol
*
* Latest source (may be newer): https://github.com/Synthetixio/synthetix/blob/master/contracts/VirtualSynthMastercopy.sol
* Docs: https://docs.synthetix.io/contracts/VirtualSynthMastercopy
*
* Contract Dependencies: 
*	- ERC20
*	- IERC20
*	- IVirtualSynth
*	- VirtualSynth
* Libraries: 
*	- SafeDecimalMath
*	- SafeMath
*
* MIT License
* ===========
*
* Copyright (c) 2021 Synthetix
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
*/



pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see `ERC20Detailed`.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * > 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);
}


/**
 * @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) {
        require(b <= a, "SafeMath: subtraction overflow");
        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-solidity/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) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, "SafeMath: division by zero");
        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) {
        require(b != 0, "SafeMath: modulo by zero");
        return a % b;
    }
}


/**
 * @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 `ERC20Mintable`.
 *
 * *For a detailed writeup see our guide [How to implement supply
 * mechanisms](https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226).*
 *
 * 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 IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

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

    uint256 private _totalSupply;

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

    /**
     * @dev See `IERC20.balanceOf`.
     */
    function balanceOf(address account) public view 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 returns (bool) {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

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

    /**
     * @dev See `IERC20.approve`.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 value) public returns (bool) {
        _approve(msg.sender, spender, value);
        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 `value`.
     * - the caller must have allowance for `sender`'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to `approve` that can be used as a mitigation for
     * problems described in `IERC20.approve`.
     *
     * Emits an `Approval` event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][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 returns (bool) {
        _approve(msg.sender, spender, _allowances[msg.sender][spender].sub(subtractedValue));
        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 {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _balances[sender] = _balances[sender].sub(amount);
        _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 {
        require(account != address(0), "ERC20: mint to the zero address");

        _totalSupply = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

     /**
     * @dev Destoys `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 value) internal {
        require(account != address(0), "ERC20: burn from the zero address");

        _totalSupply = _totalSupply.sub(value);
        _balances[account] = _balances[account].sub(value);
        emit Transfer(account, address(0), value);
    }

    /**
     * @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 value) internal {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

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

    /**
     * @dev Destoys `amount` tokens from `account`.`amount` is then deducted
     * from the caller's allowance.
     *
     * See `_burn` and `_approve`.
     */
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, msg.sender, _allowances[account][msg.sender].sub(amount));
    }
}


// Libraries


// https://docs.synthetix.io/contracts/source/libraries/safedecimalmath
library SafeDecimalMath {
    using SafeMath for uint;

    /* Number of decimal places in the representations. */
    uint8 public constant decimals = 18;
    uint8 public constant highPrecisionDecimals = 27;

    /* The number representing 1.0. */
    uint public constant UNIT = 10**uint(decimals);

    /* The number representing 1.0 for higher fidelity numbers. */
    uint public constant PRECISE_UNIT = 10**uint(highPrecisionDecimals);
    uint private constant UNIT_TO_HIGH_PRECISION_CONVERSION_FACTOR = 10**uint(highPrecisionDecimals - decimals);

    /**
     * @return Provides an interface to UNIT.
     */
    function unit() external pure returns (uint) {
        return UNIT;
    }

    /**
     * @return Provides an interface to PRECISE_UNIT.
     */
    function preciseUnit() external pure returns (uint) {
        return PRECISE_UNIT;
    }

    /**
     * @return The result of multiplying x and y, interpreting the operands as fixed-point
     * decimals.
     *
     * @dev A unit factor is divided out after the product of x and y is evaluated,
     * so that product must be less than 2**256. As this is an integer division,
     * the internal division always rounds down. This helps save on gas. Rounding
     * is more expensive on gas.
     */
    function multiplyDecimal(uint x, uint y) internal pure returns (uint) {
        /* Divide by UNIT to remove the extra factor introduced by the product. */
        return x.mul(y) / UNIT;
    }

    /**
     * @return The result of safely multiplying x and y, interpreting the operands
     * as fixed-point decimals of the specified precision unit.
     *
     * @dev The operands should be in the form of a the specified unit factor which will be
     * divided out after the product of x and y is evaluated, so that product must be
     * less than 2**256.
     *
     * Unlike multiplyDecimal, this function rounds the result to the nearest increment.
     * Rounding is useful when you need to retain fidelity for small decimal numbers
     * (eg. small fractions or percentages).
     */
    function _multiplyDecimalRound(
        uint x,
        uint y,
        uint precisionUnit
    ) private pure returns (uint) {
        /* Divide by UNIT to remove the extra factor introduced by the product. */
        uint quotientTimesTen = x.mul(y) / (precisionUnit / 10);

        if (quotientTimesTen % 10 >= 5) {
            quotientTimesTen += 10;
        }

        return quotientTimesTen / 10;
    }

    /**
     * @return The result of safely multiplying x and y, interpreting the operands
     * as fixed-point decimals of a precise unit.
     *
     * @dev The operands should be in the precise unit factor which will be
     * divided out after the product of x and y is evaluated, so that product must be
     * less than 2**256.
     *
     * Unlike multiplyDecimal, this function rounds the result to the nearest increment.
     * Rounding is useful when you need to retain fidelity for small decimal numbers
     * (eg. small fractions or percentages).
     */
    function multiplyDecimalRoundPrecise(uint x, uint y) internal pure returns (uint) {
        return _multiplyDecimalRound(x, y, PRECISE_UNIT);
    }

    /**
     * @return The result of safely multiplying x and y, interpreting the operands
     * as fixed-point decimals of a standard unit.
     *
     * @dev The operands should be in the standard unit factor which will be
     * divided out after the product of x and y is evaluated, so that product must be
     * less than 2**256.
     *
     * Unlike multiplyDecimal, this function rounds the result to the nearest increment.
     * Rounding is useful when you need to retain fidelity for small decimal numbers
     * (eg. small fractions or percentages).
     */
    function multiplyDecimalRound(uint x, uint y) internal pure returns (uint) {
        return _multiplyDecimalRound(x, y, UNIT);
    }

    /**
     * @return The result of safely dividing x and y. The return value is a high
     * precision decimal.
     *
     * @dev y is divided after the product of x and the standard precision unit
     * is evaluated, so the product of x and UNIT must be less than 2**256. As
     * this is an integer division, the result is always rounded down.
     * This helps save on gas. Rounding is more expensive on gas.
     */
    function divideDecimal(uint x, uint y) internal pure returns (uint) {
        /* Reintroduce the UNIT factor that will be divided out by y. */
        return x.mul(UNIT).div(y);
    }

    /**
     * @return The result of safely dividing x and y. The return value is as a rounded
     * decimal in the precision unit specified in the parameter.
     *
     * @dev y is divided after the product of x and the specified precision unit
     * is evaluated, so the product of x and the specified precision unit must
     * be less than 2**256. The result is rounded to the nearest increment.
     */
    function _divideDecimalRound(
        uint x,
        uint y,
        uint precisionUnit
    ) private pure returns (uint) {
        uint resultTimesTen = x.mul(precisionUnit * 10).div(y);

        if (resultTimesTen % 10 >= 5) {
            resultTimesTen += 10;
        }

        return resultTimesTen / 10;
    }

    /**
     * @return The result of safely dividing x and y. The return value is as a rounded
     * standard precision decimal.
     *
     * @dev y is divided after the product of x and the standard precision unit
     * is evaluated, so the product of x and the standard precision unit must
     * be less than 2**256. The result is rounded to the nearest increment.
     */
    function divideDecimalRound(uint x, uint y) internal pure returns (uint) {
        return _divideDecimalRound(x, y, UNIT);
    }

    /**
     * @return The result of safely dividing x and y. The return value is as a rounded
     * high precision decimal.
     *
     * @dev y is divided after the product of x and the high precision unit
     * is evaluated, so the product of x and the high precision unit must
     * be less than 2**256. The result is rounded to the nearest increment.
     */
    function divideDecimalRoundPrecise(uint x, uint y) internal pure returns (uint) {
        return _divideDecimalRound(x, y, PRECISE_UNIT);
    }

    /**
     * @dev Convert a standard decimal representation to a high precision one.
     */
    function decimalToPreciseDecimal(uint i) internal pure returns (uint) {
        return i.mul(UNIT_TO_HIGH_PRECISION_CONVERSION_FACTOR);
    }

    /**
     * @dev Convert a high precision decimal to a standard decimal representation.
     */
    function preciseDecimalToDecimal(uint i) internal pure returns (uint) {
        uint quotientTimesTen = i / (UNIT_TO_HIGH_PRECISION_CONVERSION_FACTOR / 10);

        if (quotientTimesTen % 10 >= 5) {
            quotientTimesTen += 10;
        }

        return quotientTimesTen / 10;
    }
}


// https://docs.synthetix.io/contracts/source/interfaces/isynth
interface ISynth {
    // Views
    function currencyKey() external view returns (bytes32);

    function transferableSynths(address account) external view returns (uint);

    // Mutative functions
    function transferAndSettle(address to, uint value) external returns (bool);

    function transferFromAndSettle(
        address from,
        address to,
        uint value
    ) external returns (bool);

    // Restricted: used internally to Synthetix
    function burn(address account, uint amount) external;

    function issue(address account, uint amount) external;
}


// https://docs.synthetix.io/contracts/source/interfaces/iaddressresolver
interface IAddressResolver {
    function getAddress(bytes32 name) external view returns (address);

    function getSynth(bytes32 key) external view returns (address);

    function requireAndGetAddress(bytes32 name, string calldata reason) external view returns (address);
}


interface IVirtualSynth {
    // Views
    function balanceOfUnderlying(address account) external view returns (uint);

    function rate() external view returns (uint);

    function readyToSettle() external view returns (bool);

    function secsLeftInWaitingPeriod() external view returns (uint);

    function settled() external view returns (bool);

    function synth() external view returns (ISynth);

    // Mutative functions
    function settle(address account) external;
}


// https://docs.synthetix.io/contracts/source/interfaces/iexchanger
interface IExchanger {
    // Views
    function calculateAmountAfterSettlement(
        address from,
        bytes32 currencyKey,
        uint amount,
        uint refunded
    ) external view returns (uint amountAfterSettlement);

    function isSynthRateInvalid(bytes32 currencyKey) external view returns (bool);

    function maxSecsLeftInWaitingPeriod(address account, bytes32 currencyKey) external view returns (uint);

    function settlementOwing(address account, bytes32 currencyKey)
        external
        view
        returns (
            uint reclaimAmount,
            uint rebateAmount,
            uint numEntries
        );

    function hasWaitingPeriodOrSettlementOwing(address account, bytes32 currencyKey) external view returns (bool);

    function feeRateForExchange(bytes32 sourceCurrencyKey, bytes32 destinationCurrencyKey)
        external
        view
        returns (uint exchangeFeeRate);

    function getAmountsForExchange(
        uint sourceAmount,
        bytes32 sourceCurrencyKey,
        bytes32 destinationCurrencyKey
    )
        external
        view
        returns (
            uint amountReceived,
            uint fee,
            uint exchangeFeeRate
        );

    function priceDeviationThresholdFactor() external view returns (uint);

    function waitingPeriodSecs() external view returns (uint);

    // Mutative functions
    function exchange(
        address from,
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey,
        address destinationAddress
    ) external returns (uint amountReceived);

    function exchangeOnBehalf(
        address exchangeForAddress,
        address from,
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey
    ) external returns (uint amountReceived);

    function exchangeWithTracking(
        address from,
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey,
        address destinationAddress,
        address originator,
        bytes32 trackingCode
    ) external returns (uint amountReceived);

    function exchangeOnBehalfWithTracking(
        address exchangeForAddress,
        address from,
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey,
        address originator,
        bytes32 trackingCode
    ) external returns (uint amountReceived);

    function exchangeWithVirtual(
        address from,
        bytes32 sourceCurrencyKey,
        uint sourceAmount,
        bytes32 destinationCurrencyKey,
        address destinationAddress,
        bytes32 trackingCode
    ) external returns (uint amountReceived, IVirtualSynth vSynth);

    function settle(address from, bytes32 currencyKey)
        external
        returns (
            uint reclaimed,
            uint refunded,
            uint numEntries
        );

    function setLastExchangeRateForSynth(bytes32 currencyKey, uint rate) external;

    function suspendSynthWithInvalidRate(bytes32 currencyKey) external;
}


// Inheritance


// Libraries


// Internal references


// Note: use OZ's IERC20 here as using ours will complain about conflicting names
// during the build


// https://docs.synthetix.io/contracts/source/contracts/virtualsynth
// Note: this contract should be treated as an abstract contract and should not be directly deployed.
//       On higher versions of solidity, it would be marked with the `abstract` keyword.
//       This contracts implements logic that is only intended to be accessed behind a proxy.
//       For the deployed "mastercopy" version, see VirtualSynthMastercopy.
contract VirtualSynth is ERC20, IVirtualSynth {
    using SafeMath for uint;
    using SafeDecimalMath for uint;

    IERC20 public synth;
    IAddressResolver public resolver;

    bool public settled = false;

    uint8 public constant decimals = 18;

    // track initial supply so we can calculate the rate even after all supply is burned
    uint public initialSupply;

    // track final settled amount of the synth so we can calculate the rate after settlement
    uint public settledAmount;

    bytes32 public currencyKey;

    bool public initialized = false;

    function initialize(
        IERC20 _synth,
        IAddressResolver _resolver,
        address _recipient,
        uint _amount,
        bytes32 _currencyKey
    ) external {
        require(!initialized, "vSynth already initialized");
        initialized = true;

        synth = _synth;
        resolver = _resolver;
        currencyKey = _currencyKey;

        // Assumption: the synth will be issued to us within the same transaction,
        // and this supply matches that
        _mint(_recipient, _amount);

        initialSupply = _amount;

        // Note: the ERC20 base contract does not have a constructor, so we do not have to worry
        // about initializing its state separately
    }

    // INTERNALS

    function exchanger() internal view returns (IExchanger) {
        return IExchanger(resolver.requireAndGetAddress("Exchanger", "Exchanger contract not found"));
    }

    function secsLeft() internal view returns (uint) {
        return exchanger().maxSecsLeftInWaitingPeriod(address(this), currencyKey);
    }

    function calcRate() internal view returns (uint) {
        if (initialSupply == 0) {
            return 0;
        }

        uint synthBalance;

        if (!settled) {
            synthBalance = IERC20(address(synth)).balanceOf(address(this));
            (uint reclaim, uint rebate, ) = exchanger().settlementOwing(address(this), currencyKey);

            if (reclaim > 0) {
                synthBalance = synthBalance.sub(reclaim);
            } else if (rebate > 0) {
                synthBalance = synthBalance.add(rebate);
            }
        } else {
            synthBalance = settledAmount;
        }

        return synthBalance.divideDecimalRound(initialSupply);
    }

    function balanceUnderlying(address account) internal view returns (uint) {
        uint vBalanceOfAccount = balanceOf(account);

        return vBalanceOfAccount.multiplyDecimalRound(calcRate());
    }

    function settleSynth() internal {
        if (settled) {
            return;
        }
        settled = true;

        exchanger().settle(address(this), currencyKey);

        settledAmount = IERC20(address(synth)).balanceOf(address(this));

        emit Settled(totalSupply(), settledAmount);
    }

    // VIEWS

    function name() external view returns (string memory) {
        return string(abi.encodePacked("Virtual Synth ", currencyKey));
    }

    function symbol() external view returns (string memory) {
        return string(abi.encodePacked("v", currencyKey));
    }

    // get the rate of the vSynth to the synth.
    function rate() external view returns (uint) {
        return calcRate();
    }

    // show the balance of the underlying synth that the given address has, given
    // their proportion of totalSupply
    function balanceOfUnderlying(address account) external view returns (uint) {
        return balanceUnderlying(account);
    }

    function secsLeftInWaitingPeriod() external view returns (uint) {
        return secsLeft();
    }

    function readyToSettle() external view returns (bool) {
        return secsLeft() == 0;
    }

    // PUBLIC FUNCTIONS

    // Perform settlement of the underlying exchange if required,
    // then burn the accounts vSynths and transfer them their owed balanceOfUnderlying
    function settle(address account) external {
        settleSynth();

        IERC20(address(synth)).transfer(account, balanceUnderlying(account));

        _burn(account, balanceOf(account));
    }

    event Settled(uint totalSupply, uint amountAfterSettled);
}


// https://docs.synthetix.io/contracts/source/contracts/virtualsynthmastercopy
// Note: this is the "frozen" mastercopy of the VirtualSynth contract that should be linked to from
//       proxies.
contract VirtualSynthMastercopy is VirtualSynth {
    constructor() public ERC20() {
        // Freeze mastercopy on deployment so it can never be initialized with real arguments
        initialized = true;
    }
}

[{"inputs":[],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"owner","type":"address"},{"indexed":true,"internalType":"address","name":"spender","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Approval","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"totalSupply","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"amountAfterSettled","type":"uint256"}],"name":"Settled","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"from","type":"address"},{"indexed":true,"internalType":"address","name":"to","type":"address"},{"indexed":false,"internalType":"uint256","name":"value","type":"uint256"}],"name":"Transfer","type":"event"},{"constant":true,"inputs":[{"internalType":"address","name":"owner","type":"address"},{"internalType":"address","name":"spender","type":"address"}],"name":"allowance","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"approve","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"balanceOf","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"balanceOfUnderlying","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"currencyKey","outputs":[{"internalType":"bytes32","name":"","type":"bytes32"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"decimals","outputs":[{"internalType":"uint8","name":"","type":"uint8"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"subtractedValue","type":"uint256"}],"name":"decreaseAllowance","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"spender","type":"address"},{"internalType":"uint256","name":"addedValue","type":"uint256"}],"name":"increaseAllowance","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"initialSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"contract IERC20","name":"_synth","type":"address"},{"internalType":"contract IAddressResolver","name":"_resolver","type":"address"},{"internalType":"address","name":"_recipient","type":"address"},{"internalType":"uint256","name":"_amount","type":"uint256"},{"internalType":"bytes32","name":"_currencyKey","type":"bytes32"}],"name":"initialize","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"initialized","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"name","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"rate","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"readyToSettle","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"resolver","outputs":[{"internalType":"contract IAddressResolver","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"secsLeftInWaitingPeriod","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"account","type":"address"}],"name":"settle","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"settled","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"settledAmount","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"symbol","outputs":[{"internalType":"string","name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"synth","outputs":[{"internalType":"contract IERC20","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"totalSupply","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"transfer","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"sender","type":"address"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"transferFrom","outputs":[{"internalType":"bool","name":"","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"}]

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

SafeDecimalMath : 0x1a60e2e2a8be0bc2b6381dd31fd3fd5f9a28de4c