// File: contracts/connectors/Uniswap/IUniswapConnector.sol



pragma solidity >=0.6.0;

interface IUniswapConnector {}

// File: contracts/connectors/Uniswap/UniswapConnector.sol



pragma solidity >=0.6.0;

/**
 * @title   Combines Uniswap V2 Protocol functions with Primitive V1.
 * @author  Primitive
 */

// Uniswap
import {
    IUniswapV2Router02
} from "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";
import {
    IUniswapV2Factory
} from "@uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol";
// Primitive
import { IOption } from "../../option/interfaces/IOption.sol";
import { IRegistry } from "../../option/interfaces/IRegistry.sol";
import { ITrader } from "../../option/interfaces/ITrader.sol";
import { TraderLib } from "../../option/libraries/TraderLib.sol";
import { IWethConnector } from "../WETH/IWethConnector.sol";
// Open Zeppelin
import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
import {
    ReentrancyGuard
} from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";

contract UniswapConnector is Ownable, ReentrancyGuard {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    IUniswapV2Router02 public router;
    IUniswapV2Factory public factory;
    ITrader public trader;
    IRegistry public registry;
    address public quoteToken; // Designated stablecoin for Primitive.

    event Initialized(address indexed from, address indexed quoteToken);
    event UpdatedRouter(address indexed from, address indexed newRouter);
    event UpdatedFactory(address indexed from, address indexed newFactory);
    event UpdatedTrader(address indexed from, address indexed newTrader);
    event UpdatedRegistry(address indexed from, address indexed newRegistry);
    event UpdatedQuoteToken(address indexed from, address indexed newQuote);

    event RolledOptions(
        address indexed from,
        address indexed optionFrom,
        address indexed optionTo,
        uint256 quantity
    );
    event RolledOptionLiquidity(
        address indexed from,
        address indexed optionMarketFrom,
        address indexed optionMarketTo,
        uint256 liquidity
    );

    // solhint-disable-next-line no-empty-blocks
    constructor() public {}

    // ==== Setup Functions ====

    function initialize(
        address router_,
        address factory_,
        address trader_,
        address registry_,
        address quoteToken_
    ) external onlyOwner {
        require(address(router) == address(0x0), "ERR_INITIALIZED");
        require(address(factory) == address(0x0), "ERR_INITIALIZED");
        require(address(trader) == address(0x0), "ERR_INITIALIZED");
        require(address(registry) == address(0x0), "ERR_INITIALIZED");
        require(quoteToken == address(0x0), "ERR_INITIALIZED");
        router = IUniswapV2Router02(router_);
        factory = IUniswapV2Factory(factory_);
        trader = ITrader(trader_);
        registry = IRegistry(registry_);
        quoteToken = quoteToken_;
        emit Initialized(msg.sender, quoteToken_);
    }

    /**
     * @dev Sets the Uniswap V2 Router address to use.
     */
    function setRouter(address router_) external onlyOwner {
        router = IUniswapV2Router02(router_);
        emit UpdatedRouter(msg.sender, router_);
    }

    /**
     * @dev Sets the Uniswap V2 Factory address to use.
     */
    function setFactory(address factory_) external onlyOwner {
        factory = IUniswapV2Factory(factory_);
        emit UpdatedFactory(msg.sender, factory_);
    }

    /**
     * @dev Sets the Primitive V1 Trader address to use.
     */
    function setTrader(address trader_) external onlyOwner {
        trader = ITrader(trader_);
        emit UpdatedTrader(msg.sender, trader_);
    }

    /**
     * @dev Sets the Primitive V1 Registry address to use.
     */
    function setRegistry(address registry_) external onlyOwner {
        registry = IRegistry(registry_);
        emit UpdatedRegistry(msg.sender, registry_);
    }

    /**
     * @dev Sets the designated stablecoin to use (paired token in Uniswap pools).
     */
    function setQuoteToken(address quoteToken_) external onlyOwner {
        quoteToken = quoteToken_;
        emit UpdatedQuoteToken(msg.sender, quoteToken_);
    }

    // ==== Trading Functions ====

    /**
     * @dev Mints options using underlyingTokens provided by user, then swaps on Uniswap V2.
     * Combines Primitive "mintOptions" function with Uniswap V2 Router "swapExactTokensForTokens" function.
     * @notice If the first address in the path is not the optionToken address, the tx will fail.
     * underlyingToken -> optionToken -> quoteToken.
     * @param optionToken The address of the Oracle-less Primitive option.
     * @param amountIn The quantity of options to mint and then sell.
     * @param amountOutMin The minimum quantity of tokens to receive in exchange for the optionTokens.
     * @param path The token addresses to trade through using their Uniswap V2 pools. Assumes path[0] = option.
     * @param to The address to send the optionToken proceeds and redeem tokens to.
     * @param deadline The timestamp for a trade to fail at if not successful.
     * @return bool Whether the transaction was successful or not.
     */
    function mintOptionsThenSwapToTokens(
        IOption optionToken,
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (bool) {
        // Pulls underlyingTokens from msg.sender, then pushes underlyingTokens to option contract.
        // Mints option and redeem tokens to this contract.
        (uint256 outputOptions, uint256 outputRedeems) = TraderLib.safeMint(
            optionToken,
            amountIn,
            address(this)
        );

        // Swaps option tokens to the token specified at the end of the path, then sends to msg.sender.
        // Reverts if the first address in the path is not the optionToken address.
        (, bool success) = _swapExactOptionsForTokens(
            address(optionToken),
            outputOptions,
            amountOutMin,
            path,
            to,
            deadline
        );
        // Fail early if the swap failed.
        require(success, "ERR_SWAP_FAILED");

        // Send redeemTokens (short options) to the "to" address.
        IERC20(optionToken.redeemToken()).safeTransfer(to, outputRedeems);
        return success;
    }

    /**
     * @dev Combines Uniswap V2 Router "removeLiquidity" function with Primitive "closeOptions" function.
     * @notice Pulls UNI-V2 liquidity shares with option<>quote token and redeemToken from msg.sender.
     * Then closes the optionTokens and withdraws underlyingTokens to the "to" address.
     * Sends quoteTokens from the burned UNI-V2 liquidity shares to the "to" address.
     * UNI-V2 -> optionToken -> underlyingToken.
     * @param optionAddress The address of the option that will be closed from burned UNI-V2 liquidity shares.
     * @param liquidity The quantity of liquidity tokens to pull from msg.sender and burn.
     * @param amountAMin The minimum quantity of optionTokens to receive from removing liquidity.
     * @param amountBMin The minimum quantity of quoteTokens to receive from removing liquidity.
     * @param to The address that receives quoteTokens from burned UNI-V2, and underlyingTokens from closed options.
     * @param deadline The timestamp to expire a pending transaction.
     */
    function removeLiquidityThenCloseOptions(
        address optionAddress,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) public nonReentrant returns (uint256, uint256) {
        // Store in memory for gas savings.
        address quoteToken_ = quoteToken;
        IOption optionToken = IOption(optionAddress);
        //IUniswapV2Router02 router_ = router;

        {
            // Gets the Uniswap V2 Pair address for optionAddress and quoteToken.
            // Transfers the LP tokens for the pair to this contract.
            // Warning: external call to a non-trusted address `msg.sender`.
            address pair = getUniswapMarketForOption(optionAddress);
            IERC20(pair).safeTransferFrom(msg.sender, address(this), liquidity);
            IERC20(pair).approve(address(router), uint256(-1));
        }

        // Remove liquidity from Uniswap V2 pool to receive pool tokens (option + quote tokens).
        (uint256 amountOptions, uint256 amountQuote) = router.removeLiquidity(
            optionAddress,
            quoteToken_,
            liquidity,
            amountAMin,
            amountBMin,
            address(this),
            deadline
        );

        // Approves trader to pull option and redeem tokens from this contract to close options.
        ITrader trader_ = trader;
        {
            //address redeemToken = optionToken.redeemToken();
            IERC20(optionAddress).approve(address(trader_), uint256(-1));
            IERC20(optionToken.redeemToken()).approve(
                address(trader_),
                uint256(-1)
            );

            // Calculate equivalent quantity of redeem (short option) tokens to close the option position.
            // Need to cancel base units and have quote units remaining.
            uint256 requiredRedeems = amountOptions
                .mul(optionToken.getQuoteValue())
                .div(optionToken.getBaseValue());

            // Pull the required redeemTokens from msg.sender to this contract.
            IERC20(optionToken.redeemToken()).safeTransferFrom(
                msg.sender,
                address(this),
                requiredRedeems
            );
        }

        // Pushes option and redeem tokens to the option contract and calls "closeOption".
        // Receives underlyingTokens and sends them to the "to" address.
        trader_.safeClose(optionToken, amountOptions, to);

        // Send the quoteTokens received from burning liquidity shares to the "to" address.
        IERC20(quoteToken_).safeTransfer(to, amountQuote);

        return (amountOptions, amountQuote);
    }

    /**
     * @dev Combines "removeLiquidityThenCloseOptions" function with "addLiquidityWithUnderlying" fuction.
     * @notice Rolls UNI-V2 liquidity in an option<>quote pair to a different option<>quote pair.
     * UNI-V2 -> rollFromOption -> underlyingToken -> rollToOption -> UNI-V2.
     * @param rollFromOption The optionToken address to close a UNI-V2 position.
     * @param rollToOption The optionToken address to open a UNI-V2 position.
     * @param liquidity The quantity of UNI-V2 shares to roll from the first Uniswap pool.
     * @param amountAMin The minimum quantity of optionTokens to receive from removing liquidity.
     * @param amountBMin The minimum quantity of quoteTokens to receive from removing liquidity.
     * @param to The address that receives the UNI-V2 shares that have been rolled.
     * @param deadline The timestamp to expire a pending transaction.
     */
    function rollOptionLiquidity(
        address rollFromOption,
        address rollToOption,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (bool) {
        (
            uint256 outUnderlyings,
            uint256 outQuote
        ) = removeLiquidityThenCloseOptions(
            rollFromOption,
            liquidity,
            amountAMin,
            amountBMin,
            to,
            deadline
        );

        bool success = addLiquidityWithUnderlying(
            rollToOption,
            outUnderlyings,
            outQuote,
            amountAMin,
            amountBMin,
            to,
            deadline
        );

        require(success, "ERR_ADD_LIQUIDITY_FAIL");

        emit RolledOptionLiquidity(
            msg.sender,
            rollFromOption,
            rollToOption,
            liquidity
        );

        return success;
    }

    /**
     * @dev Closes an option position and opens a new one using the freed underlyingTokens.
     * @notice Pulls option and redeem tokens from msg.sender, then sends minted option + redeems to receiver.
     * rollFromOption -> underlyingToken -> rollToOption.
     * @param rollFromOption The optionToken to close.
     * @param rollToOption The optionToken to mint.
     * @param rollQuantity The quantity of underlyingTokens to receive from closed options then use to mint new options.
     * @param receiver The address that receives newly minted option and redeem tokens.
     */
    function rollOption(
        address rollFromOption,
        address rollToOption,
        uint256 rollQuantity,
        address receiver
    ) external returns (bool) {
        // Close the rollFromOption to receive underlyingTokens.
        // Sends the underlyingTokens to this contract.
        (, , uint256 outUnderlyings) = TraderLib.safeClose(
            IOption(rollFromOption),
            rollQuantity,
            address(this)
        );

        // Store in memory for gas savings.
        ITrader trader_ = trader;

        // Approve underlyingTokens to be sent to the Primitive Trader contract.
        IERC20(IOption(rollFromOption).getUnderlyingTokenAddress()).approve(
            address(trader_),
            uint256(-1)
        );

        // Mint rollToOptions using the underlyingTokens received from closing the rollFromOptions.
        // Pulls underlyingTokens from this contract and sends them to the rollToOption contract.
        // Sends minted option and redeem tokens to the "receiver" address.
        (uint256 outputOptions, ) = trader_.safeMint(
            IOption(rollToOption),
            outUnderlyings,
            receiver
        );

        // An event is emitted because a position was atomically rolled without additional capital.
        emit RolledOptions(
            msg.sender,
            rollFromOption,
            rollToOption,
            outputOptions
        );
        return true;
    }

    // ==== Liquidity Functions ====

    /**
     * @dev Adds liquidity to an option<>quote token pair by minting optionTokens with underlyingTokens.
     * @notice Pulls underlying tokens from msg.sender and pushes UNI-V2 liquidity tokens to the "to" address.
     * underlyingToken -> optionToken -> UNI-V2.
     * @param optionAddress The address of the optionToken to mint then provide liquidity for.
     * @param quantityOptions The quantity of underlyingTokens to use to mint optionTokens.
     * @param quantityQuoteTokens The quantity of quoteTokens to add with optionTokens to the Uniswap V2 Pair.
     * @param minQuantityOptions The minimum quantity of optionTokens expected to provide liquidity with.
     * @param minQuantityQuoteTokens The minimum quantity of quoteTokens expected to provide liquidity with.
     * @param to The address that receives UNI-V2 shares.
     * @param deadline The timestamp to expire a pending transaction.
     */
    function addLiquidityWithUnderlying(
        address optionAddress,
        uint256 quantityOptions,
        uint256 quantityQuoteTokens,
        uint256 minQuantityOptions,
        uint256 minQuantityQuoteTokens,
        address to,
        uint256 deadline
    ) public nonReentrant returns (bool) {
        // Store in memory for gas savings.
        IUniswapV2Router02 router_ = router;
        address quoteToken_ = quoteToken;

        // Pull quote tokens from msg.sender to add to Uniswap V2 Pair.
        // Warning: calls into msg.sender using `safeTransferFrom`. Msg.sender is not trusted.
        IERC20(quoteToken_).safeTransferFrom(
            msg.sender,
            address(this),
            quantityQuoteTokens
        );

        // Pulls underlyingTokens from msg.sender to this contract.
        // Pushes underlyingTokens to option contract and mints option + redeem tokens to this contract.
        // Warning: calls into msg.sender using `safeTransferFrom`. Msg.sender is not trusted.
        (uint256 outputOptions, uint256 outputRedeems) = TraderLib.safeMint(
            IOption(optionAddress),
            quantityOptions,
            address(this)
        );

        // Approves Uniswap V2 Pair to transfer option and quote tokens from this contract.
        IERC20(optionAddress).approve(address(router_), uint256(-1));
        IERC20(quoteToken_).approve(address(router_), uint256(-1));

        // Adds liquidity to Uniswap V2 Pair and returns liquidity shares to the "to" address.
        router_.addLiquidity(
            optionAddress,
            quoteToken,
            outputOptions,
            quantityQuoteTokens,
            minQuantityOptions,
            minQuantityQuoteTokens,
            to,
            deadline
        );

        // Send redeemTokens (short option tokens) from minting option operation to msg.sender.
        IERC20(IOption(optionAddress).redeemToken()).safeTransfer(
            msg.sender,
            outputRedeems
        );

        return true;
    }

    // ==== Internal Functions ====

    /**
     * @dev Calls the "swapExactTokensForTokens" function on the Uniswap V2 Router 02 Contract.
     * @notice Fails early if the address in the beginning of the path is not the optionToken address.
     * @param optionAddress The address of the optionToken to swap from.
     * @param amountIn The quantity of optionTokens to swap with.
     * @param amountOutMin The minimum quantity of tokens to receive in exchange for the optionTokens swapped.
     * @param path The token addresses to trade through using their Uniswap V2 pools. Assumes path[0] = option.
     * @param to The address to send the optionToken proceeds and redeem tokens to.
     * @param deadline The timestamp for a trade to fail at if not successful.
     */
    function _swapExactOptionsForTokens(
        address optionAddress,
        uint256 amountIn,
        uint256 amountOutMin,
        address[] memory path,
        address to,
        uint256 deadline
    ) internal returns (uint256[] memory amounts, bool success) {
        // Fails early if the token being swapped from is not the optionToken.
        require(path[0] == optionAddress, "ERR_PATH_OPTION_START");

        // Store router in memory for gas savings.
        IUniswapV2Router02 router_ = router;

        // Approve the uniswap router to be able to transfer options from this contract.
        IERC20(optionAddress).approve(address(router_), uint256(-1));

        // Call the Uniswap V2 function to swap optionTokens to quoteTokens.
        (amounts) = router_.swapExactTokensForTokens(
            amountIn,
            amountOutMin,
            path,
            to,
            deadline
        );
        success = true;
    }

    // ==== Management Functions ====

    /**
     * @dev Creats a Uniswap pair for option<>quote tokens.
     * @param optionAddress The address of the option to deploy a Uniswap V2 Pair for with the quoteToken.
     */
    function deployUniswapMarket(address optionAddress)
        external
        returns (address)
    {
        address uniswapPair = factory.createPair(optionAddress, quoteToken);
        return uniswapPair;
    }

    // ==== View ====

    /**
     * @dev The maxmium deadline available for each trade.
     */
    function getMaxDeadline() public view returns (uint256) {
        // solhint-disable-next-line not-rely-on-time
        uint256 deadline = now + 15 minutes;
        return deadline;
    }

    /**
     * @dev Gets a Uniswap Pair address for an option token and quote token.
     * @param optionAddress The address of the option to get a Uniswap V2 Pair address for (with quoteToken).
     */
    function getUniswapMarketForOption(address optionAddress)
        public
        view
        returns (address)
    {
        address uniswapPair = factory.getPair(optionAddress, quoteToken);
        require(uniswapPair != address(0x0), "ERR_PAIR_DOES_NOT_EXIST");
        return uniswapPair;
    }

    /**
     * @dev Gets a Uniswap Pair address for the corresponding option parameters.
     */
    function getUniswapMarketForSeries(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) public view returns (address) {
        address optionAddress = registry.getOptionAddress(
            underlyingToken,
            strikeToken,
            base,
            quote,
            expiry
        );
        require(optionAddress != address(0x0), "ERR_OPTION_DOES_NOT_EXIST");
        return getUniswapMarketForOption(optionAddress);
    }
}

// File: @uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol



pragma solidity >=0.6.2;

import './IUniswapV2Router01.sol';

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

// File: @uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router01.sol



pragma solidity >=0.6.2;

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

// File: @uniswap/v2-core/contracts/interfaces/IUniswapV2Factory.sol



pragma solidity >=0.5.0;

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

// File: contracts/option/interfaces/IOption.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

import { IERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";

interface IOption is IERC20 {
    function mintOptions(address receiver) external returns (uint256, uint256);

    function exerciseOptions(
        address receiver,
        uint256 outUnderlyings,
        bytes calldata data
    ) external returns (uint256, uint256);

    function redeemStrikeTokens(address receiver) external returns (uint256);

    function closeOptions(address receiver)
        external
        returns (
            uint256,
            uint256,
            uint256
        );

    function redeemToken() external view returns (address);

    function getStrikeTokenAddress() external view returns (address);

    function getUnderlyingTokenAddress() external view returns (address);

    function getBaseValue() external view returns (uint256);

    function getQuoteValue() external view returns (uint256);

    function getExpiryTime() external view returns (uint256);

    function underlyingCache() external view returns (uint256);

    function strikeCache() external view returns (uint256);

    function factory() external view returns (address);

    function getCacheBalances() external view returns (uint256, uint256);

    function getAssetAddresses()
        external
        view
        returns (
            address,
            address,
            address
        );

    function getParameters()
        external
        view
        returns (
            address _underlyingToken,
            address _strikeToken,
            address _redeemToken,
            uint256 _base,
            uint256 _quote,
            uint256 _expiry
        );

    function initRedeemToken(address _redeemToken) external;

    function updateCacheBalances() external;
}

// File: @openzeppelin/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";

/**
 * @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 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 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 { }
}

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



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.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }

    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

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



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/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/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/option/interfaces/IRegistry.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

interface IRegistry {
    function pauseDeployments() external;

    function unpauseDeployments() external;

    function deployOption(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) external returns (address);

    function setOptionFactory(address optionFactory_) external;

    function setRedeemFactory(address redeemFactory_) external;

    function optionFactory() external returns (address);

    function redeemFactory() external returns (address);

    function verifyToken(address tokenAddress) external;

    function verifyExpiry(uint256 expiry) external;

    function unverifyToken(address tokenAddress) external;

    function unverifyExpiry(uint256 expiry) external;

    function calculateOptionAddress(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) external view returns (address);

    function getOptionAddress(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) external view returns (address);

    function isVerifiedOption(address optionAddress)
        external
        view
        returns (bool);
}

// File: contracts/option/interfaces/ITrader.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

import { IOption } from "./IOption.sol";

interface ITrader {
    function safeMint(
        IOption optionToken,
        uint256 mintQuantity,
        address receiver
    ) external returns (uint256, uint256);

    function safeExercise(
        IOption optionToken,
        uint256 exerciseQuantity,
        address receiver
    ) external returns (uint256, uint256);

    function safeRedeem(
        IOption optionToken,
        uint256 redeemQuantity,
        address receiver
    ) external returns (uint256);

    function safeClose(
        IOption optionToken,
        uint256 closeQuantity,
        address receiver
    )
        external
        returns (
            uint256,
            uint256,
            uint256
        );

    function safeUnwind(
        IOption optionToken,
        uint256 unwindQuantity,
        address receiver
    )
        external
        returns (
            uint256,
            uint256,
            uint256
        );
}

// File: contracts/option/libraries/TraderLib.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.2;

/**
 * @title   Trader Library
 * @notice  Internal functions that can be used to safeTransfer
 *          tokens into the option contract then call respective option contract functions.
 * @author  Primitive
 */

import { IOption } from "../interfaces/IOption.sol";
import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";

library TraderLib {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    /**
     * @dev Conducts important safety checks to safely mint option tokens.
     * @param optionToken The address of the option token to mint.
     * @param mintQuantity The quantity of option tokens to mint.
     * @param receiver The address which receives the minted option tokens.
     */
    function safeMint(
        IOption optionToken,
        uint256 mintQuantity,
        address receiver
    ) internal returns (uint256, uint256) {
        require(mintQuantity > 0, "ERR_ZERO");
        IERC20(optionToken.getUnderlyingTokenAddress()).safeTransferFrom(
            msg.sender,
            address(optionToken),
            mintQuantity
        );
        (uint256 outputOptions, uint256 outputRedeems) = optionToken
            .mintOptions(receiver);
        return (outputOptions, outputRedeems);
    }

    /**
     * @dev Swaps strikeTokens to underlyingTokens using the strike ratio as the exchange rate.
     * @notice Burns optionTokens, option contract receives strikeTokens, user receives underlyingTokens.
     * @param optionToken The address of the option contract.
     * @param exerciseQuantity Quantity of optionTokens to exercise.
     * @param receiver The underlyingTokens are sent to the receiver address.
     */
    function safeExercise(
        IOption optionToken,
        uint256 exerciseQuantity,
        address receiver
    ) internal returns (uint256, uint256) {
        require(exerciseQuantity > 0, "ERR_ZERO");
        require(
            IERC20(address(optionToken)).balanceOf(msg.sender) >=
                exerciseQuantity,
            "ERR_BAL_OPTIONS"
        );

        // Calculate quantity of strikeTokens needed to exercise quantity of optionTokens.
        uint256 inputStrikes = exerciseQuantity
            .mul(optionToken.getQuoteValue())
            .div(optionToken.getBaseValue());
        require(
            IERC20(optionToken.getStrikeTokenAddress()).balanceOf(msg.sender) >=
                inputStrikes,
            "ERR_BAL_STRIKE"
        );
        IERC20(optionToken.getStrikeTokenAddress()).safeTransferFrom(
            msg.sender,
            address(optionToken),
            inputStrikes
        );
        IERC20(address(optionToken)).safeTransferFrom(
            msg.sender,
            address(optionToken),
            exerciseQuantity
        );

        uint256 inputOptions;
        (inputStrikes, inputOptions) = optionToken.exerciseOptions(
            receiver,
            exerciseQuantity,
            new bytes(0)
        );
        return (inputStrikes, inputOptions);
    }

    /**
     * @dev Burns redeemTokens to withdraw available strikeTokens.
     * @notice inputRedeems = outputStrikes.
     * @param optionToken The address of the option contract.
     * @param redeemQuantity redeemQuantity of redeemTokens to burn.
     * @param receiver The strikeTokens are sent to the receiver address.
     */
    function safeRedeem(
        IOption optionToken,
        uint256 redeemQuantity,
        address receiver
    ) internal returns (uint256) {
        require(redeemQuantity > 0, "ERR_ZERO");
        require(
            IERC20(optionToken.redeemToken()).balanceOf(msg.sender) >=
                redeemQuantity,
            "ERR_BAL_REDEEM"
        );
        // There can be the case there is no available strikes to redeem, causing a revert.
        IERC20(optionToken.redeemToken()).safeTransferFrom(
            msg.sender,
            address(optionToken),
            redeemQuantity
        );
        uint256 inputRedeems = optionToken.redeemStrikeTokens(receiver);
        return inputRedeems;
    }

    /**
     * @dev Burn optionTokens and redeemTokens to withdraw underlyingTokens.
     * @notice The redeemTokens to burn is equal to the optionTokens * strike ratio.
     * inputOptions = inputRedeems / strike ratio = outUnderlyings
     * @param optionToken The address of the option contract.
     * @param closeQuantity Quantity of optionTokens to burn.
     * (Implictly will burn the strike ratio quantity of redeemTokens).
     * @param receiver The underlyingTokens are sent to the receiver address.
     */
    function safeClose(
        IOption optionToken,
        uint256 closeQuantity,
        address receiver
    )
        internal
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        require(closeQuantity > 0, "ERR_ZERO");
        require(
            IERC20(address(optionToken)).balanceOf(msg.sender) >= closeQuantity,
            "ERR_BAL_OPTIONS"
        );

        // Calculate the quantity of redeemTokens that need to be burned. (What we mean by Implicit).
        uint256 inputRedeems = closeQuantity
            .mul(optionToken.getQuoteValue())
            .div(optionToken.getBaseValue());
        require(
            IERC20(optionToken.redeemToken()).balanceOf(msg.sender) >=
                inputRedeems,
            "ERR_BAL_REDEEM"
        );
        IERC20(optionToken.redeemToken()).safeTransferFrom(
            msg.sender,
            address(optionToken),
            inputRedeems
        );
        IERC20(address(optionToken)).safeTransferFrom(
            msg.sender,
            address(optionToken),
            closeQuantity
        );

        uint256 inputOptions;
        uint256 outUnderlyings;
        (inputRedeems, inputOptions, outUnderlyings) = optionToken.closeOptions(
            receiver
        );
        return (inputRedeems, inputOptions, outUnderlyings);
    }

    /**
     * @dev Burn redeemTokens to withdraw underlyingTokens and strikeTokens from expired options.
     * @param optionToken The address of the option contract.
     * @param unwindQuantity Quantity of option tokens used to calculate the amount of redeem tokens to burn.
     * @param receiver The underlyingTokens are sent to the receiver address and the redeemTokens are burned.
     */
    function safeUnwind(
        IOption optionToken,
        uint256 unwindQuantity,
        address receiver
    )
        internal
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        // Checks
        require(unwindQuantity > 0, "ERR_ZERO");
        // solhint-disable-next-line not-rely-on-time
        require(
            optionToken.getExpiryTime() < block.timestamp,
            "ERR_NOT_EXPIRED"
        );

        // Calculate amount of redeems required
        uint256 inputRedeems = unwindQuantity
            .mul(optionToken.getQuoteValue())
            .div(optionToken.getBaseValue());
        require(
            IERC20(optionToken.redeemToken()).balanceOf(msg.sender) >=
                inputRedeems,
            "ERR_BAL_REDEEM"
        );
        IERC20(optionToken.redeemToken()).safeTransferFrom(
            msg.sender,
            address(optionToken),
            inputRedeems
        );

        uint256 inputOptions;
        uint256 outUnderlyings;
        (inputRedeems, inputOptions, outUnderlyings) = optionToken.closeOptions(
            receiver
        );

        return (inputRedeems, inputOptions, outUnderlyings);
    }
}

// File: @openzeppelin/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: contracts/connectors/WETH/IWethConnector.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

// Primitive
import { IOption } from "../../option/interfaces/IOption.sol";

interface IWethConnector {
    function safeMintWithETH(IOption optionToken, address receiver)
        external
        payable
        returns (uint256, uint256);

    function safeExerciseWithETH(IOption optionToken, address receiver)
        external
        payable
        returns (uint256, uint256);

    function safeExerciseForETH(
        IOption optionToken,
        uint256 exerciseQuantity,
        address receiver
    ) external returns (uint256, uint256);

    function safeRedeemForETH(
        IOption optionToken,
        uint256 redeemQuantity,
        address receiver
    ) external returns (uint256);

    function safeCloseForETH(
        IOption optionToken,
        uint256 closeQuantity,
        address receiver
    )
        external
        returns (
            uint256,
            uint256,
            uint256
        );

    function safeUnwindForETH(
        IOption optionToken,
        uint256 unwindQuantity,
        address receiver
    )
        external
        returns (
            uint256,
            uint256,
            uint256
        );
}

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



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/utils/ReentrancyGuard.sol



pragma solidity ^0.6.0;

/**
 * @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 ReentrancyGuard {
    bool private _notEntered;

    constructor () internal {
        // 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;
    }
}

// File: contracts/connectors/WETH/IWETH.sol



pragma solidity >=0.5.0;

interface IWETH {
    function deposit() external payable;

    function transfer(address to, uint256 value) external returns (bool);

    function withdraw(uint256) external;
}

// File: contracts/connectors/WETH/WethConnector.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

/**
 * @title   Weth Connector for bridging ether to WETH Primitive options.
 * @notice  Abstracts the interfacing with the protocol's option contract for ease-of-use.
 *          Manages operations involving options with WETH as the underlying or strike asset.
 *          Accepts deposits in ethers and withdraws ethers.
 * @author  Primitive
 */

// WETH Interface
import { IWETH } from "./IWETH.sol";
// Primitive
import { IOption } from "../../option/interfaces/IOption.sol";
import { TraderLib } from "../../option/libraries/TraderLib.sol";
import { IWethConnector } from "./IWethConnector.sol";
// Open Zeppelin
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import {
    ReentrancyGuard
} from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";

contract WethConnector is IWethConnector, ReentrancyGuard {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    IWETH public weth;

    event WethConnectorMint(
        address indexed from,
        address indexed option,
        uint256 outputOptions,
        uint256 outputRedeems
    );
    event WethConnectorExercise(
        address indexed from,
        address indexed option,
        uint256 outUnderlyings,
        uint256 inStrikes
    );
    event WethConnectorRedeem(
        address indexed from,
        address indexed option,
        uint256 inRedeems
    );
    event WethConnectorClose(
        address indexed from,
        address indexed option,
        uint256 inOptions
    );

    event WethConnectorUnwind(
        address indexed from,
        address indexed option,
        uint256 inOptions
    );

    /**
     * @dev Checks the quantity of an operation to make sure its not zero. Fails early.
     */
    modifier nonZero(uint256 quantity) {
        require(quantity > 0, "ERR_ZERO");
        _;
    }

    /**
     * @dev Since the WethConnector contract is responsible for converting between ethers and WETH,
     * the contract is initialized with the address for WETH.
     */
    constructor(address payable _weth) public {
        weth = IWETH(_weth);
    }

    /**
     * @dev If ether is sent to this contract through a normal transaction, it will fail, unless
     * it was the WETH contract who sent it.
     */
    receive() external payable {
        assert(msg.sender == address(weth));
    }

    // ==== Operation Functions ====

    /**
     * @dev Mints msg.value quantity of options and "quote" (option parameter) quantity of redeem tokens.
     * @notice This function is for options that have WETH as the underlying asset.
     * @param optionToken The address of the option token to mint.
     * @param receiver The address which receives the minted option and redeem tokens.
     */
    function safeMintWithETH(IOption optionToken, address receiver)
        external
        override
        payable
        nonReentrant
        nonZero(msg.value)
        returns (uint256, uint256)
    {
        // Check to make sure we are minting a WETH call option.
        address underlyingAddress = optionToken.getUnderlyingTokenAddress();
        require(address(weth) == underlyingAddress, "ERR_NOT_WETH");

        // Convert ethers into WETH, then send WETH to option contract in preparation of calling mintOptions().
        _depositEthSendWeth(address(optionToken));

        // Mint the option and redeem tokens.
        (uint256 outputOptions, uint256 outputRedeems) = optionToken
            .mintOptions(receiver);

        emit WethConnectorMint(
            msg.sender,
            address(optionToken),
            outputOptions,
            outputRedeems
        );

        return (outputOptions, outputRedeems);
    }

    /**
     * @dev Swaps msg.value of strikeTokens (ethers) to underlyingTokens.
     * Uses the strike ratio as the exchange rate. Strike ratio = base / quote.
     * Msg.value (quote units) * base / quote = base units (underlyingTokens) to withdraw.
     * @notice This function is for options with WETH as the strike asset.
     * Burns option tokens, accepts ethers, and pushes out underlyingTokens.
     * @param optionToken The address of the option contract.
     * @param receiver The underlyingTokens are sent to the receiver address.
     */
    function safeExerciseWithETH(IOption optionToken, address receiver)
        external
        override
        payable
        nonReentrant
        nonZero(msg.value)
        returns (uint256, uint256)
    {
        // Require one of the option's assets to be WETH.
        address strikeAddress = optionToken.getStrikeTokenAddress();
        require(strikeAddress == address(weth), "ERR_NOT_WETH");

        uint256 inputStrikes = msg.value;
        // Calculate quantity of optionTokens needed to burn.
        // An ether put option with strike price $300 has a "base" value of 300, and a "quote" value of 1.
        // To calculate how many options are needed to be burned, we need to cancel out the "quote" units.
        // The input strike quantity can be multiplied by the strike ratio to cancel out "quote" units.
        // 1 ether (quote units) * 300 (base units) / 1 (quote units) = 300 inputOptions
        uint256 inputOptions = inputStrikes.mul(optionToken.getBaseValue()).div(
            optionToken.getQuoteValue()
        );

        // Fail early if msg.sender does not have enough optionTokens to burn.
        require(
            IERC20(address(optionToken)).balanceOf(msg.sender) >= inputOptions,
            "ERR_BAL_OPTIONS"
        );

        // Wrap the ethers into WETH, and send the WETH to the option contract to prepare for calling exerciseOptions().
        _depositEthSendWeth(address(optionToken));

        // Send the option tokens required to prepare for calling exerciseOptions().
        IERC20(address(optionToken)).safeTransferFrom(
            msg.sender,
            address(optionToken),
            inputOptions
        );

        // Burns the transferred option tokens, stores the strike asset (ether), and pushes underlyingTokens
        // to the receiver address.
        (inputStrikes, inputOptions) = optionToken.exerciseOptions(
            receiver,
            inputOptions,
            new bytes(0)
        );

        emit WethConnectorExercise(
            msg.sender,
            address(optionToken),
            inputOptions,
            inputStrikes
        );

        return (inputStrikes, inputOptions);
    }

    /**
     * @dev Swaps strikeTokens to underlyingTokens, WETH, which is converted to ethers before withdrawn.
     * Uses the strike ratio as the exchange rate. Strike ratio = base / quote.
     * @notice This function is for options with WETH as the underlying asset.
     * Burns option tokens, pulls strikeTokens, and pushes out ethers.
     * @param optionToken The address of the option contract.
     * @param exerciseQuantity Quantity of optionTokens to exercise.
     * @param receiver The underlyingTokens (ethers) are sent to the receiver address.
     */
    function safeExerciseForETH(
        IOption optionToken,
        uint256 exerciseQuantity,
        address receiver
    )
        external
        override
        nonReentrant
        nonZero(exerciseQuantity)
        returns (uint256, uint256)
    {
        // Require one of the option's assets to be WETH.
        address underlyingAddress = optionToken.getUnderlyingTokenAddress();
        address strikeAddress = optionToken.getStrikeTokenAddress();
        require(underlyingAddress == address(weth), "ERR_NOT_WETH");

        // Fails early if msg.sender does not have enough optionTokens.
        require(
            IERC20(address(optionToken)).balanceOf(msg.sender) >=
                exerciseQuantity,
            "ERR_BAL_OPTIONS"
        );

        // Calculate quantity of strikeTokens needed to exercise quantity of optionTokens.
        uint256 inputStrikes = exerciseQuantity
            .mul(optionToken.getQuoteValue())
            .div(optionToken.getBaseValue());

        // Fails early if msg.sender does not have enough strikeTokens.
        require(
            IERC20(strikeAddress).balanceOf(msg.sender) >= inputStrikes,
            "ERR_BAL_STRIKE"
        );

        // Send strikeTokens to option contract to prepare for calling exerciseOptions().
        IERC20(strikeAddress).safeTransferFrom(
            msg.sender,
            address(optionToken),
            inputStrikes
        );

        // Send the option tokens to prepare for calling exerciseOptions().
        IERC20(address(optionToken)).safeTransferFrom(
            msg.sender,
            address(optionToken),
            exerciseQuantity
        );

        // Burns the optionTokens sent, stores the strikeTokens sent, and pushes underlyingTokens
        // to this contract.
        uint256 inputOptions;
        (inputStrikes, inputOptions) = optionToken.exerciseOptions(
            address(this),
            exerciseQuantity,
            new bytes(0)
        );

        // Converts the withdrawn WETH to ethers, then sends the ethers to the receiver address.
        _withdrawEthAndSend(receiver, exerciseQuantity);

        emit WethConnectorExercise(
            msg.sender,
            address(optionToken),
            exerciseQuantity,
            inputStrikes
        );

        return (inputStrikes, inputOptions);
    }

    /**
     * @dev Burns redeem tokens to withdraw strike tokens (ethers) at a 1:1 ratio.
     * @notice This function is for options that have WETH as the strike asset.
     * Converts WETH to ethers, and withdraws ethers to the receiver address.
     * @param optionToken The address of the option contract.
     * @param redeemQuantity The quantity of redeemTokens to burn.
     * @param receiver The strikeTokens (ethers) are sent to the receiver address.
     */
    function safeRedeemForETH(
        IOption optionToken,
        uint256 redeemQuantity,
        address receiver
    ) external override nonReentrant nonZero(redeemQuantity) returns (uint256) {
        // Require strikeToken to be WETH.
        address strikeAddress = optionToken.getStrikeTokenAddress();
        require(strikeAddress == address(weth), "ERR_NOT_WETH");

        // Fail early if msg.sender does not have enough redeemTokens.
        address redeemAddress = optionToken.redeemToken();
        require(
            IERC20(redeemAddress).balanceOf(msg.sender) >= redeemQuantity,
            "ERR_BAL_REDEEM"
        );

        // Send redeemTokens to option contract in preparation for calling redeemStrikeTokens().
        IERC20(redeemAddress).safeTransferFrom(
            msg.sender,
            address(optionToken),
            redeemQuantity
        );

        // If options have not been exercised, there will be no strikeTokens to redeem, causing a revert.
        // Burns the redeem tokens that were sent to the contract, and withdraws the same quantity of WETH.
        // Sends the withdrawn WETH to this contract, so that it can be unwrapped prior to being sent to receiver.
        uint256 inputRedeems = optionToken.redeemStrikeTokens(address(this));

        // Unwrap the redeemed WETH and then send the ethers to the receiver.
        _withdrawEthAndSend(receiver, redeemQuantity);

        emit WethConnectorRedeem(
            msg.sender,
            address(optionToken),
            inputRedeems
        );
        return inputRedeems;
    }

    /**
     * @dev Burn optionTokens and redeemTokens to withdraw underlyingTokens (ethers).
     * @notice This function is for options with WETH as the underlying asset.
     * WETH underlyingTokens are converted to ethers before being sent to receiver.
     * The redeemTokens to burn is equal to the optionTokens * strike ratio.
     * inputOptions = inputRedeems / strike ratio = outUnderlyings
     * @param optionToken The address of the option contract.
     * @param closeQuantity Quantity of optionTokens to burn and an input to calculate how many redeems to burn.
     * @param receiver The underlyingTokens (ethers) are sent to the receiver address.
     */
    function safeCloseForETH(
        IOption optionToken,
        uint256 closeQuantity,
        address receiver
    )
        external
        override
        nonReentrant
        nonZero(closeQuantity)
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        // Require the optionToken to have WETH as the underlying asset.
        address underlyingAddress = optionToken.getUnderlyingTokenAddress();
        require(address(weth) == underlyingAddress, "ERR_NOT_WETH");

        // Fail early if msg.sender does not have enough optionTokens to burn.
        require(
            IERC20(address(optionToken)).balanceOf(msg.sender) >= closeQuantity,
            "ERR_BAL_OPTIONS"
        );

        // Calculate the quantity of redeemTokens that need to be burned.
        uint256 inputRedeems = closeQuantity
            .mul(optionToken.getQuoteValue())
            .div(optionToken.getBaseValue());

        // Fail early is msg.sender does not have enough redeemTokens to burn.
        require(
            IERC20(optionToken.redeemToken()).balanceOf(msg.sender) >=
                inputRedeems,
            "ERR_BAL_REDEEM"
        );

        // Send redeem and option tokens in preparation of calling closeOptions().
        IERC20(optionToken.redeemToken()).safeTransferFrom(
            msg.sender,
            address(optionToken),
            inputRedeems
        );
        IERC20(address(optionToken)).safeTransferFrom(
            msg.sender,
            address(optionToken),
            closeQuantity
        );

        // Call the closeOptions() function to burn option and redeem tokens and withdraw underlyingTokens.
        uint256 inputOptions;
        uint256 outUnderlyings;
        (inputRedeems, inputOptions, outUnderlyings) = optionToken.closeOptions(
            address(this)
        );

        // Since underlyngTokens are WETH, unwrap them then send the ethers to the receiver.
        _withdrawEthAndSend(receiver, closeQuantity);

        emit WethConnectorClose(msg.sender, address(optionToken), inputOptions);
        return (inputRedeems, inputOptions, outUnderlyings);
    }

    /**
     * @dev Burn redeemTokens to withdraw underlyingTokens (ethers) from expired options.
     * This function is for options with WETH as the underlying asset.
     * The underlyingTokens are WETH, which are converted to ethers prior to being sent to receiver.
     * @param optionToken The address of the option contract.
     * @param unwindQuantity Quantity of underlyingTokens (ethers) to withdraw.
     * @param receiver The underlyingTokens (ethers) are sent to the receiver address.
     */
    function safeUnwindForETH(
        IOption optionToken,
        uint256 unwindQuantity,
        address receiver
    )
        external
        override
        nonReentrant
        nonZero(unwindQuantity)
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        // Require the optionToken to have WETH as the underlying asset.
        address underlyingAddress = optionToken.getUnderlyingTokenAddress();
        require(address(weth) == underlyingAddress, "ERR_NOT_WETH");

        // If the option is not expired, fail early.
        // solhint-disable-next-line not-rely-on-time
        require(optionToken.getExpiryTime() < now, "ERR_NOT_EXPIRED");

        // Calculate the quantity of redeemTokens that need to be burned.
        uint256 inputRedeems = unwindQuantity
            .mul(optionToken.getQuoteValue())
            .div(optionToken.getBaseValue());

        // Fail early if msg.sender does not have enough redeemTokens to burn.
        require(
            IERC20(optionToken.redeemToken()).balanceOf(msg.sender) >=
                inputRedeems,
            "ERR_BAL_REDEEM"
        );

        // Send redeem in preparation of calling closeOptions().
        IERC20(optionToken.redeemToken()).safeTransferFrom(
            msg.sender,
            address(optionToken),
            inputRedeems
        );

        // Call the closeOptions() function to burn redeem tokens and withdraw underlyingTokens.
        uint256 inputOptions;
        uint256 outUnderlyings;
        (inputRedeems, inputOptions, outUnderlyings) = optionToken.closeOptions(
            address(this)
        );

        // Since underlyngTokens are WETH, unwrap them to ethers then send the ethers to the receiver.
        _withdrawEthAndSend(receiver, unwindQuantity);

        emit WethConnectorUnwind(
            msg.sender,
            address(optionToken),
            inputOptions
        );
        return (inputRedeems, inputOptions, outUnderlyings);
    }

    // ==== WETH Operations ====

    /**
     * @dev Deposits msg.value of ethers into WETH contract. Then sends WETH to "to".
     * @param to The address to send WETH ERC-20 tokens to.
     */
    function _depositEthSendWeth(address to) internal {
        // Deposit the ethers received from msg.value into the WETH contract.
        weth.deposit.value(msg.value)();

        // Send WETH.
        weth.transfer(to, msg.value);
    }

    /**
     * @dev Unwraps WETH to withrdaw ethers, which are then sent to the "to" address.
     * @param to The address to send withdrawn ethers to.
     * @param quantity The quantity of WETH to unwrap.
     */
    function _withdrawEthAndSend(address to, uint256 quantity) internal {
        // Withdraw ethers with weth.
        weth.withdraw(quantity);

        // Send ether.
        (bool success, ) = to.call.value(quantity)("");

        // Revert is call is unsuccessful.
        require(success, "ERR_SENDING_ETHER");
    }
}

// File: contracts/option/applications/factories/OptionFactory.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

/**
 * @title Factory for deploying option contracts.
 * @author Primitive
 */

import { Option, SafeMath } from "../../primitives/Option.sol";
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
import { OptionTemplateLib } from "../../libraries/OptionTemplateLib.sol";
import { NullCloneConstructor } from "../NullCloneConstructor.sol";
import { CloneLib } from "../../libraries/CloneLib.sol";
import { IOptionFactory } from "../../interfaces/IOptionFactory.sol";

contract OptionFactory is IOptionFactory, Ownable, NullCloneConstructor {
    using SafeMath for uint256;

    address public override optionTemplate;

    constructor(address registry) public {
        transferOwnership(registry);
    }

    /**
     * @dev Deploys the bytecode for the Option contract.
     */
    function deployOptionTemplate() public override {
        optionTemplate = OptionTemplateLib.deployTemplate();
    }

    /**
     * @dev Deploys a create2 clone of the option template contract.
     * @param underlyingToken The address of the underlying ERC-20 token.
     * @param strikeToken The address of the strike ERC-20 token.
     * @param base The quantity of underlying tokens per unit of quote amount of strike tokens.
     * @param quote The quantity of strike tokens per unit of base amount of underlying tokens.
     * @param expiry The unix timestamp for option expiry.
     */
    function deployClone(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) external override onlyOwner returns (address) {
        require(optionTemplate != address(0x0), "ERR_NO_DEPLOYED_TEMPLATE");

        // Calculates the salt for create2.
        bytes32 salt = keccak256(
            abi.encodePacked(
                OptionTemplateLib.OPTION_SALT(),
                underlyingToken,
                strikeToken,
                base,
                quote,
                expiry
            )
        );

        // Deploys the clone using the template contract and calculated salt.
        address optionAddress = CloneLib.create2Clone(
            optionTemplate,
            uint256(salt)
        );

        // Sets the initial state of the option with the parameter arguments.
        Option(optionAddress).initialize(
            underlyingToken,
            strikeToken,
            base,
            quote,
            expiry
        );

        return optionAddress;
    }

    /**
     * @dev Only the factory can call the initRedeemToken function to set the redeem token address.
     * This function is only callable by the Registry contract (the owner).
     */
    function initRedeemToken(address optionAddress, address redeemAddress)
        external
        override
        onlyOwner
    {
        Option(optionAddress).initRedeemToken(redeemAddress);
    }

    /**
     * @dev Calculates the option token's address using the five option parameters.
     * @return The address of the option with the parameter arguments.
     */
    function calculateOptionAddress(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) external override view returns (address) {
        // Calculates the salt using the parameter arguments and the salt used in the template contract
        // create2 deployment.
        bytes32 salt = keccak256(
            abi.encodePacked(
                OptionTemplateLib.OPTION_SALT(),
                underlyingToken,
                strikeToken,
                base,
                quote,
                expiry
            )
        );
        address optionAddress = CloneLib.deriveInstanceAddress(
            optionTemplate,
            salt
        );
        return optionAddress;
    }
}

// File: contracts/option/primitives/Option.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

/**
 * @title   Vanilla Option Token
 * @notice  This is a low-level contract that is designed to be interacted with by
 *          other sophisticated smart contracts which have important safety checks,
 *          and not by externally owned accounts.
 *          Incorrect usage through direct interaction from externally owned accounts
 *          can lead to the loss of funds.
 *          Use Primitive's Trader.sol contract to interact with this contract safely.
 * @author  Primitive
 */

import { IOption } from "../interfaces/IOption.sol";
import { IRedeem } from "../interfaces/IRedeem.sol";
import { IFlash } from "../interfaces/IFlash.sol";
import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import { ERC20 } from "./ERC20.sol";
import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";

contract Option is IOption, ERC20 {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    struct OptionParameters {
        address underlyingToken;
        address strikeToken;
        uint256 base;
        uint256 quote;
        uint256 expiry;
    }

    OptionParameters public optionParameters;

    // solhint-disable-next-line const-name-snakecase
    uint256 public override underlyingCache;
    uint256 public override strikeCache;
    address public override redeemToken;
    address public override factory;
    bool private _notEntered;

    string public constant name = "Primitive V1 Option";
    string public constant symbol = "PRM";
    uint8 public constant decimals = 18;

    event Mint(address indexed from, uint256 outOptions, uint256 outRedeems);
    event Exercise(
        address indexed from,
        uint256 outUnderlyings,
        uint256 inStrikes
    );
    event Redeem(address indexed from, uint256 inRedeems);
    event Close(address indexed from, uint256 outUnderlyings);
    event UpdatedCacheBalances(uint256 underlyingCache, uint256 strikeCache);
    event InitializedRedeem(
        address indexed caller,
        address indexed redeemToken
    );

    // solhint-disable-next-line no-empty-blocks
    constructor() public {}

    /**
     * @dev Sets the intial state for the contract. Only called immediately after deployment.
     * @param underlyingToken The address of the underlying asset.
     * @param strikeToken The address of the strike asset.
     * @param base The quantity of underlying tokens per quote amount of strike tokens.
     * @param quote The quantity of strike tokens per base amount of underlying tokens.
     * @param expiry The expiration date for the option.
     */
    function initialize(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) public {
        require(factory == address(0x0), "ERR_IS_INITIALIZED");
        require(underlyingToken != strikeToken, "ERR_SAME_ASSETS");
        require(base > 0, "ERR_BASE_ZERO");
        require(quote > 0, "ERR_QUOTE_ZERO");
        require(expiry >= block.timestamp, "ERR_EXPIRY");
        factory = msg.sender;
        optionParameters = OptionParameters(
            underlyingToken,
            strikeToken,
            base,
            quote,
            expiry
        );
        _notEntered = true;
    }

    modifier notExpired {
        // solhint-disable-next-line not-rely-on-time
        require(isNotExpired(), "ERR_EXPIRED");
        _;
    }

    /**
     * @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;
    }

    /**
     * @dev Called after the option contract is initialized, and a redeem token has been deployed.
     * @notice Entangles a redeem token to this option contract permanently.
     * @param redeemToken_ The address of the redeem token.
     */
    function initRedeemToken(address redeemToken_) external override {
        require(msg.sender == factory, "ERR_NOT_OWNER");
        require(redeemToken == address(0x0), "ERR_REDEEM_INITIALIZED");
        redeemToken = redeemToken_;
        emit InitializedRedeem(msg.sender, redeemToken_);
    }

    /**
     * @dev Updates the cached balances to match the actual current balances.
     * Attempting to transfer tokens to this contract directly, in a separate transaction,
     * is incorrect and could result in loss of funds. Calling this function will permanently lock any excess
     * underlying or strike tokens which were erroneously sent to this contract.
     */
    function updateCacheBalances() external override nonReentrant {
        _updateCacheBalances(
            IERC20(optionParameters.underlyingToken).balanceOf(address(this)),
            IERC20(optionParameters.strikeToken).balanceOf(address(this))
        );
    }

    /**
     * @dev Sets the cache balances to new values.
     */
    function _updateCacheBalances(
        uint256 underlyingBalance,
        uint256 strikeBalance
    ) private {
        underlyingCache = underlyingBalance;
        strikeCache = strikeBalance;
        emit UpdatedCacheBalances(underlyingBalance, strikeBalance);
    }

    /* === STATE MUTABLE === */

    /**
     * @dev Warning: This low-level function should be called from a contract which performs important safety checks.
     * This function should never be called directly by an externally owned account.
     * A sophsticated smart contract should make the important checks to make sure the correct amount of tokens
     * are transferred into this contract prior to the function call. If an incorrect amount of tokens are transferred
     * into this contract, and this function is called, it can result in the loss of funds.
     * Mints optionTokens at a 1:1 ratio to underlyingToken deposits. Also mints Redeem tokens at a base:quote ratio.
     * @notice inUnderlyings = outOptionTokens. inUnderlying / strike ratio = outRedeemTokens.
     * @param receiver The newly minted tokens are sent to the receiver address.
     */
    function mintOptions(address receiver)
        external
        override
        nonReentrant
        notExpired
        returns (uint256, uint256)
    {
        // Save on gas because this variable is used twice.
        uint256 underlyingBalance = IERC20(optionParameters.underlyingToken)
            .balanceOf(address(this));

        // Mint optionTokens equal to the difference between current and cached balance of underlyingTokens.
        uint256 inUnderlyings = underlyingBalance.sub(underlyingCache);

        // Calculate the quantity of redeemTokens to mint.
        uint256 outRedeems = inUnderlyings.mul(optionParameters.quote).div(
            optionParameters.base
        );
        require(outRedeems > 0, "ERR_ZERO");

        // Mint the optionTokens and redeemTokens.
        IRedeem(redeemToken).mint(receiver, outRedeems);
        _mint(receiver, inUnderlyings);

        // Update the underlyingCache.
        _updateCacheBalances(underlyingBalance, strikeCache);
        emit Mint(msg.sender, inUnderlyings, outRedeems);
        return (inUnderlyings, outRedeems);
    }

    /**
     * @dev Warning: This low-level function should be called from a contract which performs important safety checks.
     * This function should never be called directly by an externally owned account.
     * A sophsticated smart contract should make the important checks to make sure the correct amount of tokens
     * are transferred into this contract prior to the function call. If an incorrect amount of tokens are transferred
     * into this contract, and this function is called, it can result in the loss of funds.
     * Sends out underlyingTokens then checks to make sure they are returned or paid for.
     * This function enables flash exercises and flash loans. Only smart contracts who implement
     * their own IFlash interface should be calling this function to initiate a flash exercise/loan.
     * @notice If the underlyingTokens are returned, only the fee has to be paid.
     * @param receiver The outUnderlyings are sent to the receiver address.
     * @param outUnderlyings Quantity of underlyingTokens to safeTransfer to receiver optimistically.
     * @param data Passing in any abritrary data will trigger the flash exercise callback function.
     */
    function exerciseOptions(
        address receiver,
        uint256 outUnderlyings,
        bytes calldata data
    ) external override nonReentrant notExpired returns (uint256, uint256) {
        // Store the cached balances and token addresses in memory.
        address underlyingToken = optionParameters.underlyingToken;
        //(uint256 _underlyingCache, uint256 _strikeCache) = getCacheBalances();

        // Require outUnderlyings > 0 and balance of underlyings >= outUnderlyings.
        require(outUnderlyings > 0, "ERR_ZERO");
        require(
            IERC20(underlyingToken).balanceOf(address(this)) >= outUnderlyings,
            "ERR_BAL_UNDERLYING"
        );

        // Optimistically safeTransfer out underlyingTokens.
        IERC20(underlyingToken).safeTransfer(receiver, outUnderlyings);
        if (data.length > 0)
            IFlash(receiver).primitiveFlash(msg.sender, outUnderlyings, data);

        // Store in memory for gas savings.
        uint256 strikeBalance = IERC20(optionParameters.strikeToken).balanceOf(
            address(this)
        );
        uint256 underlyingBalance = IERC20(underlyingToken).balanceOf(
            address(this)
        );

        // Calculate the differences.
        uint256 inStrikes = strikeBalance.sub(strikeCache);
        uint256 inUnderlyings = underlyingBalance.sub(
            underlyingCache.sub(outUnderlyings)
        ); // will be > 0 if underlyingTokens are returned.

        // Either underlyingTokens or strikeTokens must be sent into the contract.
        require(inStrikes > 0 || inUnderlyings > 0, "ERR_ZERO");

        // Calculate the remaining amount of underlyingToken that needs to be paid for.
        uint256 remainder = inUnderlyings > outUnderlyings
            ? 0
            : outUnderlyings.sub(inUnderlyings);

        // Calculate the expected payment of strikeTokens.
        uint256 payment = remainder.mul(optionParameters.quote).div(
            optionParameters.base
        );

        // Assumes the cached optionToken balance is 0, which is what it should be.
        uint256 inOptions = balanceOf(address(this));

        // Enforce the invariants.
        require(inStrikes >= payment, "ERR_STRIKES_INPUT");
        require(inOptions >= remainder, "ERR_OPTIONS_INPUT");

        // Burn the optionTokens at a 1:1 ratio to outUnderlyings.
        _burn(address(this), inOptions);

        // Update the cached balances.
        _updateCacheBalances(underlyingBalance, strikeBalance);
        emit Exercise(msg.sender, outUnderlyings, inStrikes);
        return (inStrikes, inOptions);
    }

    /**
     * @dev Warning: This low-level function should be called from a contract which performs important safety checks.
     * This function should never be called directly by an externally owned account.
     * A sophsticated smart contract should make the important checks to make sure the correct amount of tokens
     * are transferred into this contract prior to the function call. If an incorrect amount of tokens are transferred
     * into this contract, and this function is called, it can result in the loss of funds.
     * Burns redeemTokens to withdraw strikeTokens at a ratio of 1:1.
     * @notice inRedeemTokens = outStrikeTokens. Only callable when strikeTokens are in the contract.
     * @param receiver The inRedeems quantity of strikeTokens are sent to the receiver address.
     */
    function redeemStrikeTokens(address receiver)
        external
        override
        nonReentrant
        returns (uint256)
    {
        address strikeToken = optionParameters.strikeToken;
        address _redeemToken = redeemToken;
        uint256 strikeBalance = IERC20(strikeToken).balanceOf(address(this));
        uint256 inRedeems = IERC20(_redeemToken).balanceOf(address(this));

        // Difference between redeemTokens balance and cache.
        require(inRedeems > 0, "ERR_ZERO");
        require(strikeBalance >= inRedeems, "ERR_BAL_STRIKE");

        // Burn redeemTokens in the contract. Send strikeTokens to receiver.
        IRedeem(_redeemToken).burn(address(this), inRedeems);
        IERC20(strikeToken).safeTransfer(receiver, inRedeems);

        // Current balances.
        strikeBalance = IERC20(strikeToken).balanceOf(address(this));

        // Update the cached balances.
        _updateCacheBalances(underlyingCache, strikeBalance);
        emit Redeem(msg.sender, inRedeems);
        return inRedeems;
    }

    /**
     * @dev Warning: This low-level function should be called from a contract which performs important safety checks.
     * This function should never be called directly by an externally owned account.
     * A sophsticated smart contract should make the important checks to make sure the correct amount of tokens
     * are transferred into this contract prior to the function call. If an incorrect amount of tokens are transferred
     * into this contract, and this function is called, it can result in the loss of funds.
     * If the option has expired, burn redeem tokens to withdraw underlying tokens.
     * If the option is not expired, burn option and redeem tokens to withdraw underlying tokens.
     * @notice inRedeemTokens / strike ratio = outUnderlyingTokens && inOptionTokens >= outUnderlyingTokens.
     * @param receiver The outUnderlyingTokens are sent to the receiver address.
     */
    function closeOptions(address receiver)
        external
        override
        nonReentrant
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        // Stores addresses and balances locally for gas savings.
        address underlyingToken = optionParameters.underlyingToken;
        address _redeemToken = redeemToken;
        uint256 underlyingBalance = IERC20(underlyingToken).balanceOf(
            address(this)
        );
        uint256 optionBalance = balanceOf(address(this));
        uint256 inRedeems = IERC20(_redeemToken).balanceOf(address(this));

        // The quantity of underlyingToken to send out it still determined by the quantity of inRedeems.
        // inRedeems is in units of strikeTokens, which is converted to underlyingTokens
        // by multiplying inRedeems by the strike ratio, which is base / quote.
        // This outUnderlyings quantity is checked against inOptions.
        // inOptions must be greater than or equal to outUnderlyings (1 option burned per 1 underlying purchased).
        // optionBalance must be greater than or equal to outUnderlyings.
        // Neither inRedeems or inOptions can be zero.
        uint256 outUnderlyings = inRedeems.mul(optionParameters.base).div(
            optionParameters.quote
        );

        // Assumes the cached balance is 0 so inOptions = balance of optionToken.
        // If optionToken is expired, optionToken does not need to be sent in. Only redeemToken.
        // solhint-disable-next-line not-rely-on-time
        uint256 inOptions = isNotExpired() ? optionBalance : outUnderlyings;
        require(inRedeems > 0 && inOptions > 0, "ERR_ZERO");
        require(
            inOptions >= outUnderlyings && underlyingBalance >= outUnderlyings,
            "ERR_BAL_UNDERLYING"
        );

        // Burn optionTokens. optionTokens are only sent into contract when not expired.
        // solhint-disable-next-line not-rely-on-time
        if (isNotExpired()) {
            _burn(address(this), inOptions);
        }

        // Send underlyingTokens to user.
        // Burn redeemTokens held in the contract.
        // User does not receive extra underlyingTokens if there was extra optionTokens in the contract.
        // User receives outUnderlyings proportional to inRedeems.
        IRedeem(_redeemToken).burn(address(this), inRedeems);
        IERC20(underlyingToken).safeTransfer(receiver, outUnderlyings);

        // Current balances of underlyingToken and redeemToken.
        underlyingBalance = IERC20(underlyingToken).balanceOf(address(this));

        // Update the cached balances.
        _updateCacheBalances(underlyingBalance, strikeCache);
        emit Close(msg.sender, outUnderlyings);
        return (inRedeems, inOptions, outUnderlyings);
    }

    /* === VIEW === */

    /**
     * @dev Returns the previously saved balances of underlying and strike tokens.
     */
    function getCacheBalances()
        public
        override
        view
        returns (uint256, uint256)
    {
        return (underlyingCache, strikeCache);
    }

    /**
     * @dev Returns the underlying, strike, and redeem token addresses.
     */
    function getAssetAddresses()
        public
        override
        view
        returns (
            address,
            address,
            address
        )
    {
        return (
            optionParameters.underlyingToken,
            optionParameters.strikeToken,
            redeemToken
        );
    }

    /**
     * @dev Returns the strike token address.
     */
    function getStrikeTokenAddress() public override view returns (address) {
        return optionParameters.strikeToken;
    }

    /**
     * @dev Returns the underlying token address.
     */
    function getUnderlyingTokenAddress()
        public
        override
        view
        returns (address)
    {
        return optionParameters.underlyingToken;
    }

    /**
     * @dev Returns the base value option parameter.
     */
    function getBaseValue() public override view returns (uint256) {
        return optionParameters.base;
    }

    /**
     * @dev Returns the quote value option parameter.
     */
    function getQuoteValue() public override view returns (uint256) {
        return optionParameters.quote;
    }

    /**
     * @dev Returns the expiry timestamp option parameter.
     */
    function getExpiryTime() public override view returns (uint256) {
        return optionParameters.expiry;
    }

    /**
     * @dev Returns the option parameters and redeem token address.
     */
    function getParameters()
        public
        override
        view
        returns (
            address _underlyingToken,
            address _strikeToken,
            address _redeemToken,
            uint256 _base,
            uint256 _quote,
            uint256 _expiry
        )
    {
        OptionParameters memory _optionParameters = optionParameters;
        _underlyingToken = _optionParameters.underlyingToken;
        _strikeToken = _optionParameters.strikeToken;
        _redeemToken = redeemToken;
        _base = _optionParameters.base;
        _quote = _optionParameters.quote;
        _expiry = _optionParameters.expiry;
    }

    /**
     * @dev Internal function to check if the option is expired.
     */
    function isNotExpired() internal view returns (bool) {
        return optionParameters.expiry >= block.timestamp;
    }
}

// File: contracts/option/interfaces/IRedeem.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

import { IERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";

interface IRedeem is IERC20 {
    function optionToken() external view returns (address);

    function factory() external view returns (address);

    function mint(address user, uint256 amount) external;

    function burn(address user, uint256 amount) external;

    function initialize(address _factory, address _optionToken) external;
}

// File: contracts/option/interfaces/IFlash.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

interface IFlash {
    function primitiveFlash(
        address receiver,
        uint256 outUnderlyings,
        bytes calldata data
    ) external;
}

// File: contracts/option/primitives/ERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @dev Modifies name, symbol, and decimals by deleting them. Implemented as constants in parent contract.
 */

import "@openzeppelin/contracts/GSN/Context.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/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;

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public override view returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public override 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
        virtual
        override
        returns (bool)
    {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender)
        public
        virtual
        override
        view
        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_;
    } */

    // ======= WARNING: ADDED FUNCTIONS =========

    /* function _setupName(string memory name_) internal {
        _name = name_;
    }

    function _setupSymbol(string memory symbol_) internal {
        _symbol = symbol_;
    } */

    // ======= END ADDED FUNCTIONS =========

    /**
     * @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/option/libraries/OptionTemplateLib.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import { Create2 } from "@openzeppelin/contracts/utils/Create2.sol";
import { Option } from "../primitives/Option.sol";

library OptionTemplateLib {
    // solhint-disable-next-line max-line-length
    bytes32
        private constant _OPTION_SALT = 0x56f3a99c8e36689645460020839ea1340cbbb2e507b7effe3f180a89db85dd87; // keccak("primitive-option")

    // solhint-disable-next-line func-name-mixedcase
    function OPTION_SALT() internal pure returns (bytes32) {
        return _OPTION_SALT;
    }

    /**
     * @dev Deploys a clone of the deployed Option.sol contract.
     */
    function deployTemplate() external returns (address implementationAddress) {
        bytes memory creationCode = type(Option).creationCode;
        implementationAddress = Create2.deploy(0, _OPTION_SALT, creationCode);
    }
}

// File: @openzeppelin/contracts/utils/Create2.sol



pragma solidity ^0.6.0;

/**
 * @dev Helper to make usage of the `CREATE2` EVM opcode easier and safer.
 * `CREATE2` can be used to compute in advance the address where a smart
 * contract will be deployed, which allows for interesting new mechanisms known
 * as 'counterfactual interactions'.
 *
 * See the https://eips.ethereum.org/EIPS/eip-1014#motivation[EIP] for more
 * information.
 */
library Create2 {
    /**
     * @dev Deploys a contract using `CREATE2`. The address where the contract
     * will be deployed can be known in advance via {computeAddress}.
     *
     * The bytecode for a contract can be obtained from Solidity with
     * `type(contractName).creationCode`.
     *
     * Requirements:
     *
     * - `bytecode` must not be empty.
     * - `salt` must have not been used for `bytecode` already.
     * - the factory must have a balance of at least `amount`.
     * - if `amount` is non-zero, `bytecode` must have a `payable` constructor.
     */
    function deploy(uint256 amount, bytes32 salt, bytes memory bytecode) internal returns (address) {
        address addr;
        require(address(this).balance >= amount, "Create2: insufficient balance");
        require(bytecode.length != 0, "Create2: bytecode length is zero");
        // solhint-disable-next-line no-inline-assembly
        assembly {
            addr := create2(amount, add(bytecode, 0x20), mload(bytecode), salt)
        }
        require(addr != address(0), "Create2: Failed on deploy");
        return addr;
    }

    /**
     * @dev Returns the address where a contract will be stored if deployed via {deploy}. Any change in the
     * `bytecodeHash` or `salt` will result in a new destination address.
     */
    function computeAddress(bytes32 salt, bytes32 bytecodeHash) internal view returns (address) {
        return computeAddress(salt, bytecodeHash, address(this));
    }

    /**
     * @dev Returns the address where a contract will be stored if deployed via {deploy} from a contract located at
     * `deployer`. If `deployer` is this contract's address, returns the same value as {computeAddress}.
     */
    function computeAddress(bytes32 salt, bytes32 bytecodeHash, address deployer) internal pure returns (address) {
        bytes32 _data = keccak256(
            abi.encodePacked(bytes1(0xff), deployer, salt, bytecodeHash)
        );
        return address(bytes20(_data << 96));
    }
}

// File: contracts/option/applications/NullCloneConstructor.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

contract NullCloneConstructor {
    // solhint-disable-next-line no-empty-blocks
    function cloneConstructor(bytes memory consData) public {
        // blank
    }
}

// File: contracts/option/libraries/CloneLib.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @title Create2 Clone Factory Library
 * @author Alan Lu, Gnosis.
 *         Raymond Pulver IV.
 */

import { Create2 } from "@openzeppelin/contracts/utils/Create2.sol";

library CloneLib {
    /**
     * @dev Calls internal creation computation function.
     */
    function computeCreationCode(address target)
        internal
        view
        returns (bytes memory clone)
    {
        clone = computeCreationCode(address(this), target);
    }

    /**
     * @dev Computes the Clone's creation code.
     */
    function computeCreationCode(address deployer, address target)
        internal
        pure
        returns (bytes memory clone)
    {
        bytes memory consData = abi.encodeWithSignature(
            "cloneConstructor(bytes)",
            new bytes(0)
        );
        clone = new bytes(99 + consData.length);
        // solhint-disable-next-line no-inline-assembly
        assembly {
            mstore(
                add(clone, 0x20),
                0x3d3d606380380380913d393d73bebebebebebebebebebebebebebebebebebebe
            )
            mstore(
                add(clone, 0x2d),
                mul(deployer, 0x01000000000000000000000000)
            )
            mstore(
                add(clone, 0x41),
                0x5af4602a57600080fd5b602d8060366000396000f3363d3d373d3d3d363d73be
            )
            mstore(add(clone, 0x60), mul(target, 0x01000000000000000000000000))
            mstore(
                add(clone, 116),
                0x5af43d82803e903d91602b57fd5bf30000000000000000000000000000000000
            )
        }
        for (uint256 i = 0; i < consData.length; i++) {
            clone[i + 99] = consData[i];
        }
    }

    /**
     * @dev Calls Open Zeppelin's Create2.computeAddress() to get an address for the clone.
     */
    function deriveInstanceAddress(address target, bytes32 salt)
        internal
        view
        returns (address)
    {
        return
            Create2.computeAddress(
                salt,
                keccak256(computeCreationCode(target))
            );
    }

    /**
     * @dev Calls Open Zeppelin's Create2.computeAddress() to get an address for the clone.
     */
    function deriveInstanceAddress(
        address from,
        address target,
        bytes32 salt
    ) internal pure returns (address) {
        return
            Create2.computeAddress(
                salt,
                keccak256(computeCreationCode(from, target)),
                from
            );
    }

    /**
     * @dev Computs creation code, and then instantiates it with create2.
     */
    function create2Clone(address target, uint256 saltNonce)
        internal
        returns (address result)
    {
        bytes memory clone = computeCreationCode(target);
        bytes32 salt = bytes32(saltNonce);

        // solhint-disable-next-line no-inline-assembly
        assembly {
            let len := mload(clone)
            let data := add(clone, 0x20)
            result := create2(0, data, len, salt)
        }

        require(result != address(0), "ERR_CREATE2_FAIL");
    }
}

// File: contracts/option/interfaces/IOptionFactory.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

interface IOptionFactory {
    function deployClone(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) external returns (address);

    function initRedeemToken(address optionAddress, address redeemAddress)
        external;

    function deployOptionTemplate() external;

    function optionTemplate() external returns (address);

    function calculateOptionAddress(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) external view returns (address);
}

// File: contracts/option/applications/factories/RedeemFactory.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

/**
 * @title Protocol Factory Contract for Redeem Tokens.
 * @notice Uses cloning technology on a deployed template contract.
 * @author Primitive
 */

import { Redeem, SafeMath } from "../../primitives/Redeem.sol";
import { RedeemTemplateLib } from "../../libraries/RedeemTemplateLib.sol";
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
import { CloneLib } from "../../libraries/CloneLib.sol";
import { NullCloneConstructor } from "../NullCloneConstructor.sol";
import { IRedeemFactory } from "../../interfaces/IRedeemFactory.sol";

contract RedeemFactory is IRedeemFactory, Ownable, NullCloneConstructor {
    using SafeMath for uint256;

    address public override redeemTemplate;

    constructor(address registry) public {
        transferOwnership(registry);
    }

    /**
     * @dev Deploys the full bytecode of the Redeem contract to be used as a template for clones.
     */
    function deployRedeemTemplate() public override {
        redeemTemplate = RedeemTemplateLib.deployTemplate();
    }

    /**
     * @dev Deploys a cloned instance of the template Redeem contract.
     * @param optionToken The address of the option token which this redeem clone will be paired with.
     * @return redeemAddress The address of the deployed Redeem token clone.
     */
    function deployClone(address optionToken)
        external
        override
        onlyOwner
        returns (address)
    {
        bytes32 salt = keccak256(
            abi.encodePacked(
                RedeemTemplateLib.REDEEM_SALT(),
                owner(),
                optionToken
            )
        );
        address redeemAddress = CloneLib.create2Clone(
            redeemTemplate,
            uint256(salt)
        );
        Redeem(redeemAddress).initialize(owner(), optionToken);
        return redeemAddress;
    }
}

// File: contracts/option/primitives/Redeem.sol



// SPDX-License-Identifier: MIT
pragma solidity 0.6.2;

/**
 * @title   Redeem Token
 * @notice  A token that is redeemable for it's paird option token's assets.
 * @author  Primitive
 */

import { IRedeem } from "../interfaces/IRedeem.sol";
import { ERC20 } from "./ERC20.sol";
import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";

contract Redeem is IRedeem, ERC20 {
    using SafeMath for uint256;

    address public override factory;
    address public override optionToken;

    string public constant name = "Primitive V1 Redeem";
    string public constant symbol = "RDM";
    uint8 public constant decimals = 18;

    // solhint-disable-next-line no-empty-blocks
    constructor() public {}

    /**
     * @dev Sets the initial state for the redeem token. Called only once and immediately after deployment.
     * @param factory_ The address of the factory contract which handles the deployment.
     * @param optionToken_ The address of the option token which this redeem token will be paired with.
     */
    function initialize(address factory_, address optionToken_)
        public
        override
    {
        require(factory == address(0x0), "ERR_IS_INITIALIZED");
        factory = factory_;
        optionToken = optionToken_;
    }

    /**
     * @dev Mints redeem tokens. Only callable by the paired option contract.
     * @param to The address to mint redeem tokens to.
     * @param amount The quantity of redeem tokens to mint.
     */
    function mint(address to, uint256 amount) external override {
        require(msg.sender == optionToken, "ERR_NOT_VALID");
        _mint(to, amount);
    }

    /**
     * @dev Burns redeem tokens. Only callable by the paired option contract.
     * @param to The address to burn redeem tokens from.
     * @param amount The quantity of redeem tokens to burn.
     */
    function burn(address to, uint256 amount) external override {
        require(msg.sender == optionToken, "ERR_NOT_VALID");
        _burn(to, amount);
    }
}

// File: contracts/option/libraries/RedeemTemplateLib.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import { Create2 } from "@openzeppelin/contracts/utils/Create2.sol";
import { Redeem } from "../primitives/Redeem.sol";

library RedeemTemplateLib {
    // solhint-disable-next-line max-line-length
    bytes32
        private constant _REDEEM_SALT = 0xe7383acf78b06b8f24cfa7359d041702736fa6a58e63dd38afea80889c4636e2; // keccak("primitive-redeem")

    // solhint-disable-next-line func-name-mixedcase
    function REDEEM_SALT() internal pure returns (bytes32) {
        return _REDEEM_SALT;
    }

    /**
     * @dev Deploys a clone of the deployed Redeem.sol contract.
     */
    function deployTemplate() external returns (address implementationAddress) {
        bytes memory creationCode = type(Redeem).creationCode;
        implementationAddress = Create2.deploy(0, _REDEEM_SALT, creationCode);
    }
}

// File: contracts/option/interfaces/IRedeemFactory.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

interface IRedeemFactory {
    function deployClone(address optionToken) external returns (address);

    function deployRedeemTemplate() external;

    function redeemTemplate() external returns (address);
}

// File: contracts/option/applications/Registry.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

/**
 * @title Protocol Registry Contract for Deployed Options.
 * @author Primitive
 */

import { IOption } from "../interfaces/IOption.sol";
import { IRegistry } from "../interfaces/IRegistry.sol";
import { IOptionFactory } from "../interfaces/IOptionFactory.sol";
import { IRedeemFactory } from "../interfaces/IRedeemFactory.sol";
import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
import { Pausable } from "@openzeppelin/contracts/utils/Pausable.sol";
import {
    ReentrancyGuard
} from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";

contract Registry is IRegistry, Ownable, Pausable, ReentrancyGuard {
    using SafeMath for uint256;

    address public override optionFactory;
    address public override redeemFactory;

    mapping(address => bool) private verifiedTokens;
    mapping(uint256 => bool) private verifiedExpiries;
    address[] public allOptionClones;

    event UpdatedOptionFactory(address indexed optionFactory_);
    event UpdatedRedeemFactory(address indexed redeemFactory_);
    event VerifiedToken(address indexed token);
    event VerifiedExpiry(uint256 expiry);
    event UnverifiedToken(address indexed token);
    event UnverifiedExpiry(uint256 expiry);
    event DeployedOptionClone(
        address indexed from,
        address indexed optionAddress,
        address indexed redeemAddress
    );

    constructor() public {
        transferOwnership(msg.sender);
    }

    /**
     * @dev Pauses the deployOption function.
     */
    function pauseDeployments() external override onlyOwner {
        _pause();
    }

    /**
     * @dev Unpauses the deployOption function.
     */
    function unpauseDeployments() external override onlyOwner {
        _unpause();
    }

    /**
     * @dev Sets the option factory contract to use for deploying clones.
     * @param optionFactory_ The address of the option factory.
     */
    function setOptionFactory(address optionFactory_)
        external
        override
        onlyOwner
    {
        optionFactory = optionFactory_;
        emit UpdatedOptionFactory(optionFactory_);
    }

    /**
     * @dev Sets the redeem factory contract to use for deploying clones.
     * @param redeemFactory_ The address of the redeem factory.
     */
    function setRedeemFactory(address redeemFactory_)
        external
        override
        onlyOwner
    {
        redeemFactory = redeemFactory_;
        emit UpdatedRedeemFactory(redeemFactory_);
    }

    /**
     * @dev Sets an ERC-20 token verification status to true.
     * @notice A "verified" token is a standard ERC-20 token that we have tested with the option contract.
     *         An example of an "unverified" token is a non-standard ERC-20 token which has not been tested.
     */
    function verifyToken(address tokenAddress) external override onlyOwner {
        require(tokenAddress != address(0x0), "ERR_ZERO_ADDRESS");
        verifiedTokens[tokenAddress] = true;
        emit VerifiedToken(tokenAddress);
    }

    /**
     * @dev Sets a verified token's verification status to false.
     */
    function unverifyToken(address tokenAddress) external override onlyOwner {
        verifiedTokens[tokenAddress] = false;
        emit UnverifiedToken(tokenAddress);
    }

    /**
     * @dev Sets an expiry timestamp's verification status to true.
     * @notice A mapping of standardized, "verified", timestamps for the options.
     */
    function verifyExpiry(uint256 expiry) external override onlyOwner {
        require(expiry >= now, "ERR_EXPIRED_TIMESTAMP");
        verifiedExpiries[expiry] = true;
        emit VerifiedExpiry(expiry);
    }

    /**
     * @dev Sets an expiry timestamp's verification status to false.
     * @notice A mapping of standardized, "verified", timestamps for the options.
     */
    function unverifyExpiry(uint256 expiry) external override onlyOwner {
        verifiedExpiries[expiry] = false;
        emit UnverifiedExpiry(expiry);
    }

    /**
     * @dev Deploys an option contract clone with create2.
     * @param underlyingToken The address of the ERC-20 underlying token.
     * @param strikeToken The address of the ERC-20 strike token.
     * @param base The quantity of underlying tokens per unit of quote amount of strike tokens.
     * @param quote The quantity of strike tokens per unit of base amount of underlying tokens.
     * @param expiry The unix timestamp of the option's expiration date.
     * @return The address of the deployed option clone.
     */
    function deployOption(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) external override nonReentrant whenNotPaused returns (address) {
        // Validation checks for option parameters.
        require(base > 0, "ERR_BASE_ZERO");
        require(quote > 0, "ERR_QUOTE_ZERO");
        require(expiry >= now, "ERR_EXPIRY");
        require(underlyingToken != strikeToken, "ERR_SAME_ASSETS");
        require(
            underlyingToken != address(0x0) && strikeToken != address(0x0),
            "ERR_ZERO_ADDRESS"
        );

        // Deploy option and redeem contract clones.
        address optionAddress = IOptionFactory(optionFactory).deployClone(
            underlyingToken,
            strikeToken,
            base,
            quote,
            expiry
        );
        address redeemAddress = IRedeemFactory(redeemFactory).deployClone(
            optionAddress
        );

        // Add the clone to the allOptionClones address array.
        allOptionClones.push(optionAddress);

        // Initialize the new option contract's paired redeem token.
        IOptionFactory(optionFactory).initRedeemToken(
            optionAddress,
            redeemAddress
        );
        emit DeployedOptionClone(msg.sender, optionAddress, redeemAddress);
        return optionAddress;
    }

    /**
     * @dev Calculates the option address deployed with create2 using the parameter arguments.
     * @param underlyingToken The address of the ERC-20 underlying token.
     * @param strikeToken The address of the ERC-20 strike token.
     * @param base The quantity of underlying tokens per unit of quote amount of strike tokens.
     * @param quote The quantity of strike tokens per unit of base amount of underlying tokens.
     * @param expiry The unix timestamp of the option's expiration date.
     * @return The address of the option with the parameter arguments.
     */
    function calculateOptionAddress(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) public override view returns (address) {
        address optionAddress = IOptionFactory(optionFactory)
            .calculateOptionAddress(
            underlyingToken,
            strikeToken,
            base,
            quote,
            expiry
        );
        return optionAddress;
    }

    /**
     * @dev Checks an option address to see if it has verified assets and expiry time.
     * @param optionAddress The address of the option token.
     * @return bool If the option has verified underlying and strike tokens, and expiry time.
     */
    function isVerifiedOption(address optionAddress)
        external
        override
        view
        returns (bool)
    {
        IOption option = IOption(optionAddress);
        address underlyingToken = option.getUnderlyingTokenAddress();
        address strikeToken = option.getStrikeTokenAddress();
        uint256 expiry = option.getExpiryTime();
        bool verifiedUnderlying = isVerifiedToken(underlyingToken);
        bool verifiedStrike = isVerifiedToken(strikeToken);
        bool verifiedExpiry = isVerifiedExpiry(expiry);
        return verifiedUnderlying && verifiedStrike && verifiedExpiry;
    }

    /**
     * @dev Returns the length of the allOptionClones address array.
     */
    function getAllOptionClonesLength() public view returns (uint256) {
        return allOptionClones.length;
    }

    /**
     * @dev Checks the verifiedTokens private mapping and returns verification status of token.
     * @return bool Verified or not verified.
     */
    function isVerifiedToken(address tokenAddress) public view returns (bool) {
        return verifiedTokens[tokenAddress];
    }

    /**
     * @dev Checks the verifiedExpiries private mapping and returns verification status of token.
     * @return bool Verified or not verified.
     */
    function isVerifiedExpiry(uint256 expiry) public view returns (bool) {
        return verifiedExpiries[expiry];
    }

    /**
     * @dev Gets the option address and returns address zero if not yet deployed.
     * @notice Will calculate the option address using the parameter arguments.
     *         Checks the code size of the address to see if the contract has been deployed yet.
     *         If contract has not been deployed, returns address zero.
     * @param underlyingToken The address of the ERC-20 underlying token.
     * @param strikeToken The address of the ERC-20 strike token.
     * @param base The quantity of underlying tokens per unit of quote amount of strike tokens.
     * @param quote The quantity of strike tokens per unit of base amount of underlying tokens.
     * @param expiry The unix timestamp of the option's expiration date.
     * @return The address of the option with the parameter arguments.
     */
    function getOptionAddress(
        address underlyingToken,
        address strikeToken,
        uint256 base,
        uint256 quote,
        uint256 expiry
    ) public override view returns (address) {
        address optionAddress = calculateOptionAddress(
            underlyingToken,
            strikeToken,
            base,
            quote,
            expiry
        );
        uint32 size = checkCodeSize(optionAddress);
        if (size > 0) {
            return optionAddress;
        } else {
            return address(0x0);
        }
    }

    /**
     * @dev Checks the code size of a target address and returns the uint32 size.
     * @param target The address to check code size.
     */
    function checkCodeSize(address target) private view returns (uint32) {
        uint32 size;
        assembly {
            size := extcodesize(target)
        }
        return size;
    }
}

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



pragma solidity ^0.6.0;

import "../GSN/Context.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 Pausable is Context {
    /**
     * @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.
     */
    constructor () internal {
        _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());
    }
}

// File: contracts/option/extensions/Trader.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.6.2;

/**
 * @title   Trader
 * @notice  Abstracts the interfacing with the protocol's option contract for ease-of-use.
 * @author  Primitive
 */

import { IOption } from "../interfaces/IOption.sol";
import { ITrader } from "../interfaces/ITrader.sol";
import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
import {
    ReentrancyGuard
} from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import { TraderLib } from "../libraries/TraderLib.sol";

contract Trader is ITrader, ReentrancyGuard {
    using SafeMath for uint256;

    address payable public weth;

    event TraderMint(
        address indexed from,
        address indexed option,
        uint256 outputOptions,
        uint256 outputRedeems
    );
    event TraderExercise(
        address indexed from,
        address indexed option,
        uint256 outUnderlyings,
        uint256 inStrikes
    );
    event TraderRedeem(
        address indexed from,
        address indexed option,
        uint256 inRedeems
    );
    event TraderClose(
        address indexed from,
        address indexed option,
        uint256 inOptions
    );

    event TraderUnwind(
        address indexed from,
        address indexed option,
        uint256 inOptions
    );

    constructor(address payable _weth) public {
        weth = _weth;
    }

    /**
     * @dev Mint options at a 1:1 ratio with deposited underlying tokens.
     * @notice Also mints redeems at a strike ratio to the deposited underlyings.
     * Warning: Calls msg.sender with safeTransferFrom.
     * @param optionToken The address of the option contract.
     * @param mintQuantity Quantity of options to mint and underlyingToken to deposit.
     * @param receiver The newly minted options and redeems are sent to the receiver address.
     */
    function safeMint(
        IOption optionToken,
        uint256 mintQuantity,
        address receiver
    ) external override nonReentrant returns (uint256, uint256) {
        (uint256 outputOptions, uint256 outputRedeems) = TraderLib.safeMint(
            optionToken,
            mintQuantity,
            receiver
        );
        emit TraderMint(
            msg.sender,
            address(optionToken),
            outputOptions,
            outputRedeems
        );
        return (outputOptions, outputRedeems);
    }

    /**
     * @dev Swaps strikeTokens to underlyingTokens using the strike ratio as the exchange rate.
     * @notice Burns optionTokens, option contract receives strikeTokens, user receives underlyingTokens.
     * @param optionToken The address of the option contract.
     * @param exerciseQuantity Quantity of optionTokens to exercise.
     * @param receiver The underlyingTokens are sent to the receiver address.
     */
    function safeExercise(
        IOption optionToken,
        uint256 exerciseQuantity,
        address receiver
    ) external override nonReentrant returns (uint256, uint256) {
        (uint256 inStrikes, uint256 inOptions) = TraderLib.safeExercise(
            optionToken,
            exerciseQuantity,
            receiver
        );
        emit TraderExercise(
            msg.sender,
            address(optionToken),
            exerciseQuantity,
            inStrikes
        );

        return (inStrikes, inOptions);
    }

    /**
     * @dev Burns redeemTokens to withdraw available strikeTokens.
     * @notice inRedeems = outStrikes.
     * @param optionToken The address of the option contract.
     * @param redeemQuantity redeemQuantity of redeemTokens to burn.
     * @param receiver The strikeTokens are sent to the receiver address.
     */
    function safeRedeem(
        IOption optionToken,
        uint256 redeemQuantity,
        address receiver
    ) external override nonReentrant returns (uint256) {
        uint256 inRedeems = TraderLib.safeRedeem(
            optionToken,
            redeemQuantity,
            receiver
        );
        emit TraderRedeem(msg.sender, address(optionToken), inRedeems);
        return inRedeems;
    }

    /**
     * @dev Burn optionTokens and redeemTokens to withdraw underlyingTokens.
     * @notice The redeemTokens to burn is equal to the optionTokens * strike ratio.
     * inOptions = inRedeems / strike ratio = outUnderlyings
     * @param optionToken The address of the option contract.
     * @param closeQuantity Quantity of optionTokens to burn.
     * (Implictly will burn the strike ratio quantity of redeemTokens).
     * @param receiver The underlyingTokens are sent to the receiver address.
     */
    function safeClose(
        IOption optionToken,
        uint256 closeQuantity,
        address receiver
    )
        external
        override
        nonReentrant
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        (
            uint256 inRedeems,
            uint256 inOptions,
            uint256 outUnderlyings
        ) = TraderLib.safeClose(optionToken, closeQuantity, receiver);
        emit TraderClose(msg.sender, address(optionToken), inOptions);
        return (inRedeems, inOptions, outUnderlyings);
    }

    /**
     * @dev Burn redeemTokens to withdraw underlyingTokens and strikeTokens from expired options.
     * @param optionToken The address of the option contract.
     * @param unwindQuantity Quantity of option tokens used to calculate the amount of redeem tokens to burn.
     * @param receiver The underlyingTokens and redeemTokens are sent to the receiver address.
     */
    function safeUnwind(
        IOption optionToken,
        uint256 unwindQuantity,
        address receiver
    )
        external
        override
        nonReentrant
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        (
            uint256 inRedeems,
            uint256 inOptions,
            uint256 outUnderlyings
        ) = TraderLib.safeUnwind(optionToken, unwindQuantity, receiver);
        emit TraderUnwind(msg.sender, address(optionToken), inOptions);
        return (inRedeems, inOptions, outUnderlyings);
    }
}

// File: contracts/test/Flash.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.2;

/**
 * @title Test Flash Exercise contract
 * @author Primitive
 */

/**
 * A flash exercise is initiated by the exerciseOptions() function in the Option.sol contract.
 * Warning: Only correctly implemented wrapper smart contracts can safely execute these flash features.
 * Underlying tokens will be sent to the msg.sender of the exerciseOptions() call first.
 * The msg.sender should be a smart contract that implements the IFlash interface, which has a single
 * function: primitiveFlash().
 * The callback function primitiveFlash() can be triggered by passing in any arbritrary data to the
 * exerciseOptions() function. If the length of the data is greater than 0, it triggers the callback.
 * The implemented primitiveFlash() callback is where customized operations can be undertaken using the
 * underlying tokens received from the flash exercise.
 * After the callback function (whether its called or not), the exerciseOptions() function checks to see
 * if it has been paid the correct amount of strike and option tokens (an actual exercise of the option),
 * or if it has received the same quantity of underlying tokens back (a flash loan).
 */

import { IOption } from "../option/interfaces/IOption.sol";
import { IFlash } from "../option/interfaces/IFlash.sol";
import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";

contract Flash is IFlash {
    using SafeMath for uint256;

    address public optionToken;

    event FlashExercise(address indexed from);

    constructor(address _optionToken) public {
        optionToken = _optionToken;
    }

    function goodFlashLoan(uint256 amount) external {
        // Call the exerciseOptions function and trigger the fallback function by passing in data
        IOption(optionToken).exerciseOptions(
            address(this),
            amount,
            new bytes(1)
        );
    }

    function badFlashLoan(uint256 amount) external {
        // Call the exerciseOptions function and trigger the fallback function by passing in data
        // bytes(2) will cause our implemented flash exercise to fail
        IOption(optionToken).exerciseOptions(
            address(this),
            amount,
            new bytes(2)
        );
    }

    /**
     * @dev An implemented primitiveFlash callback function that matches the interface in Option.sol.
     * @notice Calling the exerciseOptions() function in the Option contract will trigger this callback function.
     * @param receiver The account which receives the underlying tokens.
     * @param outUnderlyings The quantity of underlying tokens received as a flash loan.
     * @param data Any data that will be passed as an argument to the original exerciseOptions() call.
     */
    function primitiveFlash(
        address receiver,
        uint256 outUnderlyings,
        bytes calldata data
    ) external override {
        // Get the underlying token address.
        address underlyingToken = IOption(optionToken)
            .getUnderlyingTokenAddress();
        // In our test case we pass in the data param with bytes(1).
        bool good = keccak256(abi.encodePacked(data)) ==
            keccak256(abi.encodePacked(new bytes(1)));
        // If the flash exercise went through, we return the loaned underlyings.
        if (good) {
            IERC20(underlyingToken).transfer(optionToken, outUnderlyings);
        }
        emit FlashExercise(receiver);
    }
}

// File: contracts/test/OptionTest.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.2;

/**
 * @title   Option test contract.
 * @author  Primitive
 */

import "../option/primitives/Option.sol";

contract OptionTest is Option {
    // solhint-disable-next-line no-empty-blocks
    constructor() public Option() {}

    function setExpiry(uint256 expiry) public {
        optionParameters.expiry = expiry;
    }

    function setRedeemToken(address redeem) public {
        redeemToken = redeem;
    }
}

// File: contracts/test/tokens/BadERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.2;

import "@openzeppelin/contracts/GSN/Context.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/utils/Address.sol";

interface IERC20 {
    function totalSupply() external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function transfer(address recipient, uint256 amount) external;

    function allowance(address owner, address spender)
        external
        view
        returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

contract BadERC20 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;

    constructor(string memory name, string memory symbol) public {
        _name = name;
        _symbol = symbol;
        _decimals = 18;
    }

    function name() public view returns (string memory) {
        return _name;
    }

    function symbol() public view returns (string memory) {
        return _symbol;
    }

    function decimals() public view returns (uint8) {
        return _decimals;
    }

    function totalSupply() public override view returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(address account) public override view returns (uint256) {
        return _balances[account];
    }

    function transfer(address recipient, uint256 amount)
        public
        virtual
        override
    {
        _transfer(_msgSender(), recipient, amount);
    }

    function allowance(address owner, address spender)
        public
        virtual
        override
        view
        returns (uint256)
    {
        return _allowances[owner][spender];
    }

    function mint(address account, uint256 amount) public {
        _mint(account, amount);
    }

    function approve(address spender, uint256 amount)
        public
        virtual
        override
        returns (bool)
    {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public virtual override {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            _msgSender(),
            _allowances[sender][_msgSender()].sub(
                amount,
                "ERC20: transfer amount exceeds allowance"
            )
        );
    }

    function increaseAllowance(address spender, uint256 addedValue)
        public
        virtual
        returns (bool)
    {
        _approve(
            _msgSender(),
            spender,
            _allowances[_msgSender()][spender].add(addedValue)
        );
        return true;
    }

    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;
    }

    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);
    }

    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);
    }

    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);
    }

    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);
    }

    function _setupDecimals(uint8 decimals_) internal {
        _decimals = decimals_;
    }

    // solhint-disable-next-line no-empty-blocks
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        // do nothing
    }
}

// File: contracts/test/tokens/TestERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.2;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract TestERC20 is ERC20 {
    constructor(
        string memory name,
        string memory symbol,
        uint256 initialSupply
    ) public ERC20(name, symbol) {
        _mint(msg.sender, initialSupply);
    }

    /**
     * @dev Function to mint tokens
     * @param to The address that will receive the minted tokens.
     * @param value The amount of tokens to mint.
     * @return A boolean that indicates if the operation was successful.
     */
    function mint(address to, uint256 value) public returns (bool) {
        _mint(to, value);
        return true;
    }
}

// File: contracts/test/tokens/WETH9.sol



// SPDX-License-Identifier: MIT

// Copyright (C) 2015, 2016, 2017 Dapphub

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

pragma solidity ^0.6.2;

contract WETH9 {
    string public name = "Wrapped Ether";
    string public symbol = "WETH";
    uint8 public decimals = 18;

    event Approval(address indexed src, address indexed guy, uint256 wad);
    event Transfer(address indexed src, address indexed dst, uint256 wad);
    event Deposit(address indexed dst, uint256 wad);
    event Withdrawal(address indexed src, uint256 wad);

    mapping(address => uint256) public balanceOf;
    mapping(address => mapping(address => uint256)) public allowance;

    /* function() external payable {
        deposit();
    } */
    function deposit() public payable {
        balanceOf[msg.sender] += msg.value;
        emit Deposit(msg.sender, msg.value);
    }

    function withdraw(uint256 wad) public {
        require(balanceOf[msg.sender] >= wad);
        balanceOf[msg.sender] -= wad;
        msg.sender.transfer(wad);
        emit Withdrawal(msg.sender, wad);
    }

    function totalSupply() public view returns (uint256) {
        return address(this).balance;
    }

    function approve(address guy, uint256 wad) public returns (bool) {
        allowance[msg.sender][guy] = wad;
        emit Approval(msg.sender, guy, wad);
        return true;
    }

    function transfer(address dst, uint256 wad) public returns (bool) {
        return transferFrom(msg.sender, dst, wad);
    }

    function transferFrom(
        address src,
        address dst,
        uint256 wad
    ) public returns (bool) {
        require(balanceOf[src] >= wad);

        if (src != msg.sender && allowance[src][msg.sender] != uint256(-1)) {
            require(allowance[src][msg.sender] >= wad);
            allowance[src][msg.sender] -= wad;
        }

        balanceOf[src] -= wad;
        balanceOf[dst] += wad;

        emit Transfer(src, dst, wad);

        return true;
    }
}

/*
                    GNU GENERAL PUBLIC LICENSE
                       Version 3, 29 June 2007

 Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
 Everyone is permitted to copy and distribute verbatim copies
 of this license document, but changing it is not allowed.

                            Preamble

  The GNU General Public License is a free, copyleft license for
software and other kinds of works.

  The licenses for most software and other practical works are designed
to take away your freedom to share and change the works.  By contrast,
the GNU General Public License is intended to guarantee your freedom to
share and change all versions of a program--to make sure it remains free
software for all its users.  We, the Free Software Foundation, use the
GNU General Public License for most of our software; it applies also to
any other work released this way by its authors.  You can apply it to
your programs, too.

  When we speak of free software, we are referring to freedom, not
price.  Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
them if you wish), that you receive source code or can get it if you
want it, that you can change the software or use pieces of it in new
free programs, and that you know you can do these things.

  To protect your rights, we need to prevent others from denying you
these rights or asking you to surrender the rights.  Therefore, you have
certain responsibilities if you distribute copies of the software, or if
you modify it: responsibilities to respect the freedom of others.

  For example, if you distribute copies of such a program, whether
gratis or for a fee, you must pass on to the recipients the same
freedoms that you received.  You must make sure that they, too, receive
or can get the source code.  And you must show them these terms so they
know their rights.

  Developers that use the GNU GPL protect your rights with two steps:
(1) assert copyright on the software, and (2) offer you this License
giving you legal permission to copy, distribute and/or modify it.

  For the developers' and authors' protection, the GPL clearly explains
that there is no warranty for this free software.  For both users' and
authors' sake, the GPL requires that modified versions be marked as
changed, so that their problems will not be attributed erroneously to
authors of previous versions.

  Some devices are designed to deny users access to install or run
modified versions of the software inside them, although the manufacturer
can do so.  This is fundamentally incompatible with the aim of
protecting users' freedom to change the software.  The systematic
pattern of such abuse occurs in the area of products for individuals to
use, which is precisely where it is most unacceptable.  Therefore, we
have designed this version of the GPL to prohibit the practice for those
products.  If such problems arise substantially in other domains, we
stand ready to extend this provision to those domains in future versions
of the GPL, as needed to protect the freedom of users.

  Finally, every program is threatened constantly by software patents.
States should not allow patents to restrict development and use of
software on general-purpose computers, but in those that do, we wish to
avoid the special danger that patents applied to a free program could
make it effectively proprietary.  To prevent this, the GPL assures that
patents cannot be used to render the program non-free.

  The precise terms and conditions for copying, distribution and
modification follow.

                       TERMS AND CONDITIONS

  0. Definitions.

  "This License" refers to version 3 of the GNU General Public License.

  "Copyright" also means copyright-like laws that apply to other kinds of
works, such as semiconductor masks.

  "The Program" refers to any copyrightable work licensed under this
License.  Each licensee is addressed as "you".  "Licensees" and
"recipients" may be individuals or organizations.

  To "modify" a work means to copy from or adapt all or part of the work
in a fashion requiring copyright permission, other than the making of an
exact copy.  The resulting work is called a "modified version" of the
earlier work or a work "based on" the earlier work.

  A "covered work" means either the unmodified Program or a work based
on the Program.

  To "propagate" a work means to do anything with it that, without
permission, would make you directly or secondarily liable for
infringement under applicable copyright law, except executing it on a
computer or modifying a private copy.  Propagation includes copying,
distribution (with or without modification), making available to the
public, and in some countries other activities as well.

  To "convey" a work means any kind of propagation that enables other
parties to make or receive copies.  Mere interaction with a user through
a computer network, with no transfer of a copy, is not conveying.

  An interactive user interface displays "Appropriate Legal Notices"
to the extent that it includes a convenient and prominently visible
feature that (1) displays an appropriate copyright notice, and (2)
tells the user that there is no warranty for the work (except to the
extent that warranties are provided), that licensees may convey the
work under this License, and how to view a copy of this License.  If
the interface presents a list of user commands or options, such as a
menu, a prominent item in the list meets this criterion.

  1. Source Code.

  The "source code" for a work means the preferred form of the work
for making modifications to it.  "Object code" means any non-source
form of a work.

  A "Standard Interface" means an interface that either is an official
standard defined by a recognized standards body, or, in the case of
interfaces specified for a particular programming language, one that
is widely used among developers working in that language.

  The "System Libraries" of an executable work include anything, other
than the work as a whole, that (a) is included in the normal form of
packaging a Major Component, but which is not part of that Major
Component, and (b) serves only to enable use of the work with that
Major Component, or to implement a Standard Interface for which an
implementation is available to the public in source code form.  A
"Major Component", in this context, means a major essential component
(kernel, window system, and so on) of the specific operating system
(if any) on which the executable work runs, or a compiler used to
produce the work, or an object code interpreter used to run it.

  The "Corresponding Source" for a work in object code form means all
the source code needed to generate, install, and (for an executable
work) run the object code and to modify the work, including scripts to
control those activities.  However, it does not include the work's
System Libraries, or general-purpose tools or generally available free
programs which are used unmodified in performing those activities but
which are not part of the work.  For example, Corresponding Source
includes interface definition files associated with source files for
the work, and the source code for shared libraries and dynamically
linked subprograms that the work is specifically designed to require,
such as by intimate data communication or control flow between those
subprograms and other parts of the work.

  The Corresponding Source need not include anything that users
can regenerate automatically from other parts of the Corresponding
Source.

  The Corresponding Source for a work in source code form is that
same work.

  2. Basic Permissions.

  All rights granted under this License are granted for the term of
copyright on the Program, and are irrevocable provided the stated
conditions are met.  This License explicitly affirms your unlimited
permission to run the unmodified Program.  The output from running a
covered work is covered by this License only if the output, given its
content, constitutes a covered work.  This License acknowledges your
rights of fair use or other equivalent, as provided by copyright law.

  You may make, run and propagate covered works that you do not
convey, without conditions so long as your license otherwise remains
in force.  You may convey covered works to others for the sole purpose
of having them make modifications exclusively for you, or provide you
with facilities for running those works, provided that you comply with
the terms of this License in conveying all material for which you do
not control copyright.  Those thus making or running the covered works
for you must do so exclusively on your behalf, under your direction
and control, on terms that prohibit them from making any copies of
your copyrighted material outside their relationship with you.

  Conveying under any other circumstances is permitted solely under
the conditions stated below.  Sublicensing is not allowed; section 10
makes it unnecessary.

  3. Protecting Users' Legal Rights From Anti-Circumvention Law.

  No covered work shall be deemed part of an effective technological
measure under any applicable law fulfilling obligations under article
11 of the WIPO copyright treaty adopted on 20 December 1996, or
similar laws prohibiting or restricting circumvention of such
measures.

  When you convey a covered work, you waive any legal power to forbid
circumvention of technological measures to the extent such circumvention
is effected by exercising rights under this License with respect to
the covered work, and you disclaim any intention to limit operation or
modification of the work as a means of enforcing, against the work's
users, your or third parties' legal rights to forbid circumvention of
technological measures.

  4. Conveying Verbatim Copies.

  You may convey verbatim copies of the Program's source code as you
receive it, in any medium, provided that you conspicuously and
appropriately publish on each copy an appropriate copyright notice;
keep intact all notices stating that this License and any
non-permissive terms added in accord with section 7 apply to the code;
keep intact all notices of the absence of any warranty; and give all
recipients a copy of this License along with the Program.

  You may charge any price or no price for each copy that you convey,
and you may offer support or warranty protection for a fee.

  5. Conveying Modified Source Versions.

  You may convey a work based on the Program, or the modifications to
produce it from the Program, in the form of source code under the
terms of section 4, provided that you also meet all of these conditions:

    a) The work must carry prominent notices stating that you modified
    it, and giving a relevant date.

    b) The work must carry prominent notices stating that it is
    released under this License and any conditions added under section
    7.  This requirement modifies the requirement in section 4 to
    "keep intact all notices".

    c) You must license the entire work, as a whole, under this
    License to anyone who comes into possession of a copy.  This
    License will therefore apply, along with any applicable section 7
    additional terms, to the whole of the work, and all its parts,
    regardless of how they are packaged.  This License gives no
    permission to license the work in any other way, but it does not
    invalidate such permission if you have separately received it.

    d) If the work has interactive user interfaces, each must display
    Appropriate Legal Notices; however, if the Program has interactive
    interfaces that do not display Appropriate Legal Notices, your
    work need not make them do so.

  A compilation of a covered work with other separate and independent
works, which are not by their nature extensions of the covered work,
and which are not combined with it such as to form a larger program,
in or on a volume of a storage or distribution medium, is called an
"aggregate" if the compilation and its resulting copyright are not
used to limit the access or legal rights of the compilation's users
beyond what the individual works permit.  Inclusion of a covered work
in an aggregate does not cause this License to apply to the other
parts of the aggregate.

  6. Conveying Non-Source Forms.

  You may convey a covered work in object code form under the terms
of sections 4 and 5, provided that you also convey the
machine-readable Corresponding Source under the terms of this License,
in one of these ways:

    a) Convey the object code in, or embodied in, a physical product
    (including a physical distribution medium), accompanied by the
    Corresponding Source fixed on a durable physical medium
    customarily used for software interchange.

    b) Convey the object code in, or embodied in, a physical product
    (including a physical distribution medium), accompanied by a
    written offer, valid for at least three years and valid for as
    long as you offer spare parts or customer support for that product
    model, to give anyone who possesses the object code either (1) a
    copy of the Corresponding Source for all the software in the
    product that is covered by this License, on a durable physical
    medium customarily used for software interchange, for a price no
    more than your reasonable cost of physically performing this
    conveying of source, or (2) access to copy the
    Corresponding Source from a network server at no charge.

    c) Convey individual copies of the object code with a copy of the
    written offer to provide the Corresponding Source.  This
    alternative is allowed only occasionally and noncommercially, and
    only if you received the object code with such an offer, in accord
    with subsection 6b.

    d) Convey the object code by offering access from a designated
    place (gratis or for a charge), and offer equivalent access to the
    Corresponding Source in the same way through the same place at no
    further charge.  You need not require recipients to copy the
    Corresponding Source along with the object code.  If the place to
    copy the object code is a network server, the Corresponding Source
    may be on a different server (operated by you or a third party)
    that supports equivalent copying facilities, provided you maintain
    clear directions next to the object code saying where to find the
    Corresponding Source.  Regardless of what server hosts the
    Corresponding Source, you remain obligated to ensure that it is
    available for as long as needed to satisfy these requirements.

    e) Convey the object code using peer-to-peer transmission, provided
    you inform other peers where the object code and Corresponding
    Source of the work are being offered to the general public at no
    charge under subsection 6d.

  A separable portion of the object code, whose source code is excluded
from the Corresponding Source as a System Library, need not be
included in conveying the object code work.

  A "User Product" is either (1) a "consumer product", which means any
tangible personal property which is normally used for personal, family,
or household purposes, or (2) anything designed or sold for incorporation
into a dwelling.  In determining whether a product is a consumer product,
doubtful cases shall be resolved in favor of coverage.  For a particular
product received by a particular user, "normally used" refers to a
typical or common use of that class of product, regardless of the status
of the particular user or of the way in which the particular user
actually uses, or expects or is expected to use, the product.  A product
is a consumer product regardless of whether the product has substantial
commercial, industrial or non-consumer uses, unless such uses represent
the only significant mode of use of the product.

  "Installation Information" for a User Product means any methods,
procedures, authorization keys, or other information required to install
and execute modified versions of a covered work in that User Product from
a modified version of its Corresponding Source.  The information must
suffice to ensure that the continued functioning of the modified object
code is in no case prevented or interfered with solely because
modification has been made.

  If you convey an object code work under this section in, or with, or
specifically for use in, a User Product, and the conveying occurs as
part of a transaction in which the right of possession and use of the
User Product is transferred to the recipient in perpetuity or for a
fixed term (regardless of how the transaction is characterized), the
Corresponding Source conveyed under this section must be accompanied
by the Installation Information.  But this requirement does not apply
if neither you nor any third party retains the ability to install
modified object code on the User Product (for example, the work has
been installed in ROM).

  The requirement to provide Installation Information does not include a
requirement to continue to provide support service, warranty, or updates
for a work that has been modified or installed by the recipient, or for
the User Product in which it has been modified or installed.  Access to a
network may be denied when the modification itself materially and
adversely affects the operation of the network or violates the rules and
protocols for communication across the network.

  Corresponding Source conveyed, and Installation Information provided,
in accord with this section must be in a format that is publicly
documented (and with an implementation available to the public in
source code form), and must require no special password or key for
unpacking, reading or copying.

  7. Additional Terms.

  "Additional permissions" are terms that supplement the terms of this
License by making exceptions from one or more of its conditions.
Additional permissions that are applicable to the entire Program shall
be treated as though they were included in this License, to the extent
that they are valid under applicable law.  If additional permissions
apply only to part of the Program, that part may be used separately
under those permissions, but the entire Program remains governed by
this License without regard to the additional permissions.

  When you convey a copy of a covered work, you may at your option
remove any additional permissions from that copy, or from any part of
it.  (Additional permissions may be written to require their own
removal in certain cases when you modify the work.)  You may place
additional permissions on material, added by you to a covered work,
for which you have or can give appropriate copyright permission.

  Notwithstanding any other provision of this License, for material you
add to a covered work, you may (if authorized by the copyright holders of
that material) supplement the terms of this License with terms:

    a) Disclaiming warranty or limiting liability differently from the
    terms of sections 15 and 16 of this License; or

    b) Requiring preservation of specified reasonable legal notices or
    author attributions in that material or in the Appropriate Legal
    Notices displayed by works containing it; or

    c) Prohibiting misrepresentation of the origin of that material, or
    requiring that modified versions of such material be marked in
    reasonable ways as different from the original version; or

    d) Limiting the use for publicity purposes of names of licensors or
    authors of the material; or

    e) Declining to grant rights under trademark law for use of some
    trade names, trademarks, or service marks; or

    f) Requiring indemnification of licensors and authors of that
    material by anyone who conveys the material (or modified versions of
    it) with contractual assumptions of liability to the recipient, for
    any liability that these contractual assumptions directly impose on
    those licensors and authors.

  All other non-permissive additional terms are considered "further
restrictions" within the meaning of section 10.  If the Program as you
received it, or any part of it, contains a notice stating that it is
governed by this License along with a term that is a further
restriction, you may remove that term.  If a license document contains
a further restriction but permits relicensing or conveying under this
License, you may add to a covered work material governed by the terms
of that license document, provided that the further restriction does
not survive such relicensing or conveying.

  If you add terms to a covered work in accord with this section, you
must place, in the relevant source files, a statement of the
additional terms that apply to those files, or a notice indicating
where to find the applicable terms.

  Additional terms, permissive or non-permissive, may be stated in the
form of a separately written license, or stated as exceptions;
the above requirements apply either way.

  8. Termination.

  You may not propagate or modify a covered work except as expressly
provided under this License.  Any attempt otherwise to propagate or
modify it is void, and will automatically terminate your rights under
this License (including any patent licenses granted under the third
paragraph of section 11).

  However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the copyright
holder fails to notify you of the violation by some reasonable means
prior to 60 days after the cessation.

  Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.

  Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License.  If your rights have been terminated and not permanently
reinstated, you do not qualify to receive new licenses for the same
material under section 10.

  9. Acceptance Not Required for Having Copies.

  You are not required to accept this License in order to receive or
run a copy of the Program.  Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer transmission
to receive a copy likewise does not require acceptance.  However,
nothing other than this License grants you permission to propagate or
modify any covered work.  These actions infringe copyright if you do
not accept this License.  Therefore, by modifying or propagating a
covered work, you indicate your acceptance of this License to do so.

  10. Automatic Licensing of Downstream Recipients.

  Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License.  You are not responsible
for enforcing compliance by third parties with this License.

  An "entity transaction" is a transaction transferring control of an
organization, or substantially all assets of one, or subdividing an
organization, or merging organizations.  If propagation of a covered
work results from an entity transaction, each party to that
transaction who receives a copy of the work also receives whatever
licenses to the work the party's predecessor in interest had or could
give under the previous paragraph, plus a right to possession of the
Corresponding Source of the work from the predecessor in interest, if
the predecessor has it or can get it with reasonable efforts.

  You may not impose any further restrictions on the exercise of the
rights granted or affirmed under this License.  For example, you may
not impose a license fee, royalty, or other charge for exercise of
rights granted under this License, and you may not initiate litigation
(including a cross-claim or counterclaim in a lawsuit) alleging that
any patent claim is infringed by making, using, selling, offering for
sale, or importing the Program or any portion of it.

  11. Patents.

  A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based.  The
work thus licensed is called the contributor's "contributor version".

  A contributor's "essential patent claims" are all patent claims
owned or controlled by the contributor, whether already acquired or
hereafter acquired, that would be infringed by some manner, permitted
by this License, of making, using, or selling its contributor version,
but do not include claims that would be infringed only as a
consequence of further modification of the contributor version.  For
purposes of this definition, "control" includes the right to grant
patent sublicenses in a manner consistent with the requirements of
this License.

  Each contributor grants you a non-exclusive, worldwide, royalty-free
patent license under the contributor's essential patent claims, to
make, use, sell, offer for sale, import and otherwise run, modify and
propagate the contents of its contributor version.

  In the following three paragraphs, a "patent license" is any express
agreement or commitment, however denominated, not to enforce a patent
(such as an express permission to practice a patent or covenant not to
sue for patent infringement).  To "grant" such a patent license to a
party means to make such an agreement or commitment not to enforce a
patent against the party.

  If you convey a covered work, knowingly relying on a patent license,
and the Corresponding Source of the work is not available for anyone
to copy, free of charge and under the terms of this License, through a
publicly available network server or other readily accessible means,
then you must either (1) cause the Corresponding Source to be so
available, or (2) arrange to deprive yourself of the benefit of the
patent license for this particular work, or (3) arrange, in a manner
consistent with the requirements of this License, to extend the patent
license to downstream recipients.  "Knowingly relying" means you have
actual knowledge that, but for the patent license, your conveying the
covered work in a country, or your recipient's use of the covered work
in a country, would infringe one or more identifiable patents in that
country that you have reason to believe are valid.

  If, pursuant to or in connection with a single transaction or
arrangement, you convey, or propagate by procuring conveyance of, a
covered work, and grant a patent license to some of the parties
receiving the covered work authorizing them to use, propagate, modify
or convey a specific copy of the covered work, then the patent license
you grant is automatically extended to all recipients of the covered
work and works based on it.

  A patent license is "discriminatory" if it does not include within
the scope of its coverage, prohibits the exercise of, or is
conditioned on the non-exercise of one or more of the rights that are
specifically granted under this License.  You may not convey a covered
work if you are a party to an arrangement with a third party that is
in the business of distributing software, under which you make payment
to the third party based on the extent of your activity of conveying
the work, and under which the third party grants, to any of the
parties who would receive the covered work from you, a discriminatory
patent license (a) in connection with copies of the covered work
conveyed by you (or copies made from those copies), or (b) primarily
for and in connection with specific products or compilations that
contain the covered work, unless you entered into that arrangement,
or that patent license was granted, prior to 28 March 2007.

  Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.

  12. No Surrender of Others' Freedom.

  If conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License.  If you cannot convey a
covered work so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you may
not convey it at all.  For example, if you agree to terms that obligate you
to collect a royalty for further conveying from those to whom you convey
the Program, the only way you could satisfy both those terms and this
License would be to refrain entirely from conveying the Program.

  13. Use with the GNU Affero General Public License.

  Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU Affero General Public License into a single
combined work, and to convey the resulting work.  The terms of this
License will continue to apply to the part which is the covered work,
but the special requirements of the GNU Affero General Public License,
section 13, concerning interaction through a network will apply to the
combination as such.

  14. Revised Versions of this License.

  The Free Software Foundation may publish revised and/or new versions of
the GNU General Public License from time to time.  Such new versions will
be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.

  Each version is given a distinguishing version number.  If the
Program specifies that a certain numbered version of the GNU General
Public License "or any later version" applies to it, you have the
option of following the terms and conditions either of that numbered
version or of any later version published by the Free Software
Foundation.  If the Program does not specify a version number of the
GNU General Public License, you may choose any version ever published
by the Free Software Foundation.

  If the Program specifies that a proxy can decide which future
versions of the GNU General Public License can be used, that proxy's
public statement of acceptance of a version permanently authorizes you
to choose that version for the Program.

  Later license versions may give you additional or different
permissions.  However, no additional obligations are imposed on any
author or copyright holder as a result of your choosing to follow a
later version.

  15. Disclaimer of Warranty.

  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
ALL NECESSARY SERVICING, REPAIR OR CORRECTION.

  16. Limitation of Liability.

  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.

  17. Interpretation of Sections 15 and 16.

  If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.

                     END OF TERMS AND CONDITIONS

            How to Apply These Terms to Your New Programs

  If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.

  To do so, attach the following notices to the program.  It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.

    <one line to give the program's name and a brief idea of what it does.>
    Copyright (C) <year>  <name of author>

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

Also add information on how to contact you by electronic and paper mail.

  If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:

    <program>  Copyright (C) <year>  <name of author>
    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
    This is free software, and you are welcome to redistribute it
    under certain conditions; type `show c' for details.

The hypothetical commands `show w' and `show c' should show the appropriate
parts of the General Public License.  Of course, your program's commands
might be different; for a GUI interface, you would use an "about box".

  You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU GPL, see
<http://www.gnu.org/licenses/>.

  The GNU General Public License does not permit incorporating your program
into proprietary programs.  If your program is a subroutine library, you
may consider it more useful to permit linking proprietary applications with
the library.  If this is what you want to do, use the GNU Lesser General
Public License instead of this License.  But first, please read
<http://www.gnu.org/philosophy/why-not-lgpl.html>.

*/