Cryo Explorer Ethereum Mainnet

/*solhint-disable avoid-low-level-calls */
// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;
pragma experimental ABIEncoderV2;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "../ITokenTransferProxy.sol";

interface IERC20Permit {
    function permit(
        address owner,
        address spender,
        uint256 amount,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}

interface IERC20PermitLegacy {
    function permit(
        address holder,
        address spender,
        uint256 nonce,
        uint256 expiry,
        bool allowed,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}

library Utils {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    address private constant ETH_ADDRESS = address(0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE);

    uint256 private constant MAX_UINT = type(uint256).max;

    /**
   * @param fromToken Address of the source token
   * @param fromAmount Amount of source tokens to be swapped
   * @param toAmount Minimum destination token amount expected out of this swap
   * @param expectedAmount Expected amount of destination tokens without slippage
   * @param beneficiary Beneficiary address
   * 0 then 100% will be transferred to beneficiary. Pass 10000 for 100%
   * @param path Route to be taken for this swap to take place

   */
    struct SellData {
        address fromToken;
        uint256 fromAmount;
        uint256 toAmount;
        uint256 expectedAmount;
        address payable beneficiary;
        Utils.Path[] path;
        address payable partner;
        uint256 feePercent;
        bytes permit;
        uint256 deadline;
        bytes16 uuid;
    }

    struct BuyData {
        address adapter;
        address fromToken;
        address toToken;
        uint256 fromAmount;
        uint256 toAmount;
        uint256 expectedAmount;
        address payable beneficiary;
        Utils.Route[] route;
        address payable partner;
        uint256 feePercent;
        bytes permit;
        uint256 deadline;
        bytes16 uuid;
    }

    struct MegaSwapSellData {
        address fromToken;
        uint256 fromAmount;
        uint256 toAmount;
        uint256 expectedAmount;
        address payable beneficiary;
        Utils.MegaSwapPath[] path;
        address payable partner;
        uint256 feePercent;
        bytes permit;
        uint256 deadline;
        bytes16 uuid;
    }

    struct SimpleData {
        address fromToken;
        address toToken;
        uint256 fromAmount;
        uint256 toAmount;
        uint256 expectedAmount;
        address[] callees;
        bytes exchangeData;
        uint256[] startIndexes;
        uint256[] values;
        address payable beneficiary;
        address payable partner;
        uint256 feePercent;
        bytes permit;
        uint256 deadline;
        bytes16 uuid;
    }

    struct Adapter {
        address payable adapter;
        uint256 percent;
        uint256 networkFee; //NOT USED
        Route[] route;
    }

    struct Route {
        uint256 index; //Adapter at which index needs to be used
        address targetExchange;
        uint256 percent;
        bytes payload;
        uint256 networkFee; //NOT USED - Network fee is associated with 0xv3 trades
    }

    struct MegaSwapPath {
        uint256 fromAmountPercent;
        Path[] path;
    }

    struct Path {
        address to;
        uint256 totalNetworkFee; //NOT USED - Network fee is associated with 0xv3 trades
        Adapter[] adapters;
    }

    function ethAddress() internal pure returns (address) {
        return ETH_ADDRESS;
    }

    function maxUint() internal pure returns (uint256) {
        return MAX_UINT;
    }

    function approve(
        address addressToApprove,
        address token,
        uint256 amount
    ) internal {
        if (token != ETH_ADDRESS) {
            IERC20 _token = IERC20(token);

            uint256 allowance = _token.allowance(address(this), addressToApprove);

            if (allowance < amount) {
                _token.safeApprove(addressToApprove, 0);
                _token.safeIncreaseAllowance(addressToApprove, MAX_UINT);
            }
        }
    }

    function transferTokens(
        address token,
        address payable destination,
        uint256 amount
    ) internal {
        if (amount > 0) {
            if (token == ETH_ADDRESS) {
                (bool result, ) = destination.call{ value: amount, gas: 10000 }("");
                require(result, "Failed to transfer Ether");
            } else {
                IERC20(token).safeTransfer(destination, amount);
            }
        }
    }

    function tokenBalance(address token, address account) internal view returns (uint256) {
        if (token == ETH_ADDRESS) {
            return account.balance;
        } else {
            return IERC20(token).balanceOf(account);
        }
    }

    function permit(address token, bytes memory permit) internal {
        if (permit.length == 32 * 7) {
            (bool success, ) = token.call(abi.encodePacked(IERC20Permit.permit.selector, permit));
            require(success, "Permit failed");
        }

        if (permit.length == 32 * 8) {
            (bool success, ) = token.call(abi.encodePacked(IERC20PermitLegacy.permit.selector, permit));
            require(success, "Permit failed");
        }
    }

    function transferETH(address payable destination, uint256 amount) internal {
        if (amount > 0) {
            (bool result, ) = destination.call{ value: amount, gas: 10000 }("");
            require(result, "Transfer ETH failed");
        }
    }
}

// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;

// helpers
import "../AugustusSwapper.sol";
import "../lib/Utils.sol";

// interfaces
import { IFeeClaimer } from "./IFeeClaimer.sol";

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

/**
 * @title Fee Claimer
 * @author paraswap
 * @notice a contract that holds balances of ParaSwap Protocol as well as partners.
 *         the partners can later claim the tokens from this contract.
 */
contract FeeClaimer is IFeeClaimer {
    using SafeMath for uint256;
    /**@notice mapping for storing partner's and PP's share in fee of various ERC20 tokens */
    mapping(address => mapping(IERC20 => uint256)) public fees;

    /**@notice address of the augustusSwapper */
    address payable public immutable augustusSwapper;

    /**@notice amount of fees in token allocated*/
    mapping(IERC20 => uint256) public allocatedFees;

    //===constructor===
    constructor(address payable _augustusAddress) {
        augustusSwapper = _augustusAddress;
    }

    modifier onlyAugustusSwapper() {
        require(msg.sender == augustusSwapper, "FeeClaimer: 1");
        _;
    }

    //===external functions===

    /**
     * @inheritdoc IFeeClaimer
     */
    function registerFee(
        address _account,
        IERC20 _token,
        uint256 _fee
    ) external override onlyAugustusSwapper {
        uint256 _unallocatedFees = getUnallocatedFees(_token);
        if (_fee > _unallocatedFees) {
            _fee = _unallocatedFees;
        }
        allocatedFees[_token] = allocatedFees[_token].add(_fee);
        fees[_account][_token] = fees[_account][_token].add(_fee);
    }

    /**
     * @inheritdoc IFeeClaimer
     */
    function withdrawSomeERC20(
        IERC20 _token,
        uint256 _tokenAmount,
        address _recipient
    ) public override returns (bool) {
        uint256 _balance = fees[msg.sender][_token];
        require(_balance >= _tokenAmount, "FeeClaimer: 2");
        address _account = _recipient == address(0) ? msg.sender : _recipient;
        fees[msg.sender][_token] = _balance.sub(_tokenAmount);
        allocatedFees[_token] = allocatedFees[_token].sub(_tokenAmount);
        Utils.transferTokens(address(_token), payable(_account), _tokenAmount);
        return true;
    }

    /**
     * @inheritdoc IFeeClaimer
     */
    function batchWithdrawSomeERC20(
        IERC20[] calldata _tokens,
        uint256[] calldata _tokenAmounts,
        address _recipient
    ) external override returns (bool) {
        require(_tokens.length == _tokenAmounts.length, "FeeClaimer: 3");
        for (uint256 _i; _i < _tokens.length; _i++) {
            require(withdrawSomeERC20(_tokens[_i], _tokenAmounts[_i], _recipient), "FeeClaimer: 4");
        }
        return true;
    }

    /**
     * @inheritdoc IFeeClaimer
     */
    function withdrawAllERC20(IERC20 _token, address _recipient) public override returns (bool) {
        uint256 _balance = fees[msg.sender][_token];
        require(_balance > 0, "FeeClaimer: 5");
        address _account = _recipient == address(0) ? msg.sender : _recipient;
        fees[msg.sender][_token] = 0;
        allocatedFees[_token] = allocatedFees[_token].sub(_balance);
        Utils.transferTokens(address(_token), payable(_account), _balance);
        return true;
    }

    /**
     * @inheritdoc IFeeClaimer
     */
    function batchWithdrawAllERC20(IERC20[] calldata _tokens, address _recipient) external override returns (bool) {
        for (uint256 _i; _i < _tokens.length; _i++) {
            require(withdrawAllERC20(_tokens[_i], _recipient), "FeeClaimer: 6");
        }
        return true;
    }

    //===public view functions===

    /**
     * @inheritdoc IFeeClaimer
     */
    function getUnallocatedFees(IERC20 _token) public view override returns (uint256) {
        return Utils.tokenBalance(address(_token), address(this)).sub(allocatedFees[_token]);
    }

    /**
     * @inheritdoc IFeeClaimer
     */
    function getBalance(IERC20 _token, address _partner) external view override returns (uint256) {
        return fees[_partner][_token];
    }

    /**
     * @inheritdoc IFeeClaimer
     */
    function batchGetBalance(IERC20[] calldata _tokens, address _partner)
        external
        view
        override
        returns (uint256[] memory _fees)
    {
        uint256 _len = _tokens.length;
        _fees = new uint256[](_len);
        for (uint256 _i; _i < _tokens.length; _i++) {
            _fees[_i] = fees[_partner][_tokens[_i]];
        }
    }

    receive() external payable {}
}

// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;

import "./ITokenTransferProxy.sol";

contract AugustusStorage {
    struct FeeStructure {
        uint256 partnerShare;
        bool noPositiveSlippage;
        bool positiveSlippageToUser;
        uint16 feePercent;
        string partnerId;
        bytes data;
    }

    ITokenTransferProxy internal tokenTransferProxy;
    address payable internal feeWallet;

    mapping(address => FeeStructure) internal registeredPartners;

    mapping(bytes4 => address) internal selectorVsRouter;
    mapping(bytes32 => bool) internal adapterInitialized;
    mapping(bytes32 => bytes) internal adapterVsData;

    mapping(bytes32 => bytes) internal routerData;
    mapping(bytes32 => bool) internal routerInitialized;

    bytes32 public constant WHITELISTED_ROLE = keccak256("WHITELISTED_ROLE");

    bytes32 public constant ROUTER_ROLE = keccak256("ROUTER_ROLE");
}

/* solhint-disable avoid-low-level-calls*/
/* solhint-disable no-inline-assembly */
/* solhint-disable no-complex-fallback */
// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;
pragma abicoder v2;

import "@openzeppelin/contracts/access/AccessControl.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "./routers/IRouter.sol";
import "./adapters/IAdapter.sol";
import "./TokenTransferProxy.sol";
import "./ITokenTransferProxy.sol";
import "./AugustusStorage.sol";

contract AugustusSwapper is AugustusStorage, AccessControl {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    event AdapterInitialized(address indexed adapter);

    event RouterInitialized(address indexed router);

    /**
     * @dev Throws if called by any account other than the admin.
     */
    modifier onlyAdmin() {
        require(hasRole(DEFAULT_ADMIN_ROLE, msg.sender), "caller is not the admin");
        _;
    }

    constructor(address payable _feeWallet) public {
        TokenTransferProxy lTokenTransferProxy = new TokenTransferProxy();
        tokenTransferProxy = ITokenTransferProxy(lTokenTransferProxy);
        feeWallet = _feeWallet;
        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);
    }

    /*solhint-disable no-empty-blocks*/
    receive() external payable {}

    /*solhint-enable no-empty-blocks*/

    fallback() external payable {
        bytes4 selector = msg.sig;
        //Figure out the router contract for the given function
        address implementation = getImplementation(selector);
        if (implementation == address(0)) {
            _revertWithData(abi.encodeWithSelector(bytes4(keccak256("NotImplementedError(bytes4)")), selector));
        }

        //Delegate call to the router
        (bool success, bytes memory resultData) = implementation.delegatecall(msg.data);
        if (!success) {
            _revertWithData(resultData);
        }

        _returnWithData(resultData);
    }

    function initializeAdapter(address adapter, bytes calldata data) external onlyAdmin {
        require(hasRole(WHITELISTED_ROLE, adapter), "Exchange not whitelisted");
        (bool success, ) = adapter.delegatecall(abi.encodeWithSelector(IAdapter.initialize.selector, data));
        require(success, "Failed to initialize adapter");
        emit AdapterInitialized(adapter);
    }

    function initializeRouter(address router, bytes calldata data) external onlyAdmin {
        require(hasRole(ROUTER_ROLE, router), "Router not whitelisted");
        (bool success, ) = router.delegatecall(abi.encodeWithSelector(IRouter.initialize.selector, data));
        require(success, "Failed to initialize router");
        emit RouterInitialized(router);
    }

    function getImplementation(bytes4 selector) public view returns (address) {
        return selectorVsRouter[selector];
    }

    function getVersion() external pure returns (string memory) {
        return "5.0.0";
    }

    function getPartnerFeeStructure(address partner) public view returns (FeeStructure memory) {
        return registeredPartners[partner];
    }

    function getFeeWallet() external view returns (address) {
        return feeWallet;
    }

    function setFeeWallet(address payable _feeWallet) external onlyAdmin {
        require(_feeWallet != address(0), "Invalid address");
        feeWallet = _feeWallet;
    }

    function registerPartner(
        address partner,
        uint256 _partnerShare,
        bool _noPositiveSlippage,
        bool _positiveSlippageToUser,
        uint16 _feePercent,
        string calldata partnerId,
        bytes calldata _data
    ) external onlyAdmin {
        require(partner != address(0), "Invalid partner");
        FeeStructure storage feeStructure = registeredPartners[partner];
        require(feeStructure.partnerShare == 0, "Already registered");
        require(_partnerShare > 0 && _partnerShare < 10000, "Invalid values");
        require(_feePercent <= 10000, "Invalid values");

        feeStructure.partnerShare = _partnerShare;
        feeStructure.noPositiveSlippage = _noPositiveSlippage;
        feeStructure.positiveSlippageToUser = _positiveSlippageToUser;
        feeStructure.partnerId = partnerId;
        feeStructure.feePercent = _feePercent;
        feeStructure.data = _data;
    }

    function setImplementation(bytes4 selector, address implementation) external onlyAdmin {
        require(hasRole(ROUTER_ROLE, implementation), "Router is not whitelisted");
        selectorVsRouter[selector] = implementation;
    }

    /**
     * @dev Allows admin of the contract to transfer any tokens which are assigned to the contract
     * This method is for safety if by any chance tokens or ETHs are assigned to the contract by mistake
     * @dev token Address of the token to be transferred
     * @dev destination Recepient of the token
     * @dev amount Amount of tokens to be transferred
     */
    function transferTokens(
        address token,
        address payable destination,
        uint256 amount
    ) external onlyAdmin {
        if (amount > 0) {
            if (token == address(0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE)) {
                (bool result, ) = destination.call{ value: amount, gas: 10000 }("");
                require(result, "Failed to transfer Ether");
            } else {
                IERC20(token).safeTransfer(destination, amount);
            }
        }
    }

    function isAdapterInitialized(bytes32 key) public view returns (bool) {
        return adapterInitialized[key];
    }

    function getAdapterData(bytes32 key) public view returns (bytes memory) {
        return adapterVsData[key];
    }

    function isRouterInitialized(bytes32 key) public view returns (bool) {
        return routerInitialized[key];
    }

    function getRouterData(bytes32 key) public view returns (bytes memory) {
        return routerData[key];
    }

    function getTokenTransferProxy() public view returns (address) {
        return address(tokenTransferProxy);
    }

    function _revertWithData(bytes memory data) private pure {
        assembly {
            revert(add(data, 32), mload(data))
        }
    }

    function _returnWithData(bytes memory data) private pure {
        assembly {
            return(add(data, 32), mload(data))
        }
    }
}

// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;

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

interface IFeeClaimer {
    /**
     * @notice register partner's, affiliate's and PP's fee
     * @dev only callable by AugustusSwapper contract
     * @param _account account address used to withdraw fees
     * @param _token token address
     * @param _fee fee amount in token
     */
    function registerFee(
        address _account,
        IERC20 _token,
        uint256 _fee
    ) external;

    /**
     * @notice claim partner share fee in ERC20 token
     * @dev transfers ERC20 token balance to the caller's account
     *      the call will fail if withdrawer have zero balance in the contract
     * @param _token address of the ERC20 token
     * @param _recipient address
     * @return true if the withdraw was successfull
     */
    function withdrawAllERC20(IERC20 _token, address _recipient) external returns (bool);

    /**
     * @notice batch claim whole balance of fee share amount
     * @dev transfers ERC20 token balance to the caller's account
     *      the call will fail if withdrawer have zero balance in the contract
     * @param _tokens list of addresses of the ERC20 token
     * @param _recipient address of recipient
     * @return true if the withdraw was successfull
     */
    function batchWithdrawAllERC20(IERC20[] calldata _tokens, address _recipient) external returns (bool);

    /**
     * @notice claim some partner share fee in ERC20 token
     * @dev transfers ERC20 token amount to the caller's account
     *      the call will fail if withdrawer have zero balance in the contract
     * @param _token address of the ERC20 token
     * @param _recipient address
     * @return true if the withdraw was successfull
     */
    function withdrawSomeERC20(
        IERC20 _token,
        uint256 _tokenAmount,
        address _recipient
    ) external returns (bool);

    /**
     * @notice batch claim some amount of fee share in ERC20 token
     * @dev transfers ERC20 token balance to the caller's account
     *      the call will fail if withdrawer have zero balance in the contract
     * @param _tokens address of the ERC20 tokens
     * @param _tokenAmounts array of amounts
     * @param _recipient destination account addresses
     * @return true if the withdraw was successfull
     */
    function batchWithdrawSomeERC20(
        IERC20[] calldata _tokens,
        uint256[] calldata _tokenAmounts,
        address _recipient
    ) external returns (bool);

    /**
     * @notice compute unallocated fee in token
     * @param _token address of the ERC20 token
     * @return amount of unallocated token in fees
     */
    function getUnallocatedFees(IERC20 _token) external view returns (uint256);

    /**
     * @notice returns unclaimed fee amount given the token
     * @dev retrieves the balance of ERC20 token fee amount for a partner
     * @param _token address of the ERC20 token
     * @param _partner account address of the partner
     * @return amount of balance
     */
    function getBalance(IERC20 _token, address _partner) external view returns (uint256);

    /**
     * @notice returns unclaimed fee amount given the token in batch
     * @dev retrieves the balance of ERC20 token fee amount for a partner in batch
     * @param _tokens list of ERC20 token addresses
     * @param _partner account address of the partner
     * @return _fees array of the token amount
     */
    function batchGetBalance(IERC20[] calldata _tokens, address _partner)
        external
        view
        returns (uint256[] memory _fees);
}

// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;

interface IRouter {
    /**
     * @dev Certain routers/exchanges needs to be initialized.
     * This method will be called from Augustus
     */
    function initialize(bytes calldata data) external;

    /**
     * @dev Returns unique identifier for the router
     */
    function getKey() external pure returns (bytes32);

    event SwappedV3(
        bytes16 uuid,
        address partner,
        uint256 feePercent,
        address initiator,
        address indexed beneficiary,
        address indexed srcToken,
        address indexed destToken,
        uint256 srcAmount,
        uint256 receivedAmount,
        uint256 expectedAmount
    );

    event BoughtV3(
        bytes16 uuid,
        address partner,
        uint256 feePercent,
        address initiator,
        address indexed beneficiary,
        address indexed srcToken,
        address indexed destToken,
        uint256 srcAmount,
        uint256 receivedAmount,
        uint256 expectedAmount
    );
}

// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;
pragma abicoder v2;

import "../lib/Utils.sol";

interface IAdapter {
    /**
     * @dev Certain adapters needs to be initialized.
     * This method will be called from Augustus
     */
    function initialize(bytes calldata data) external;

    /**
     * @dev The function which performs the swap on an exchange.
     * @param fromToken Address of the source token
     * @param toToken Address of the destination token
     * @param fromAmount Amount of source tokens to be swapped
     * @param networkFee NOT USED - Network fee to be used in this router
     * @param route Route to be followed
     */
    function swap(
        IERC20 fromToken,
        IERC20 toToken,
        uint256 fromAmount,
        uint256 networkFee,
        Utils.Route[] calldata route
    ) external payable;
}

// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "./ITokenTransferProxy.sol";

/**
 * @dev Allows owner of the contract to transfer tokens on behalf of user.
 * User will need to approve this contract to spend tokens on his/her behalf
 * on Paraswap platform
 */
contract TokenTransferProxy is Ownable, ITokenTransferProxy {
    using SafeERC20 for IERC20;
    using Address for address;

    /**
     * @dev Allows owner of the contract to transfer tokens on user's behalf
     * @dev Swapper contract will be the owner of this contract
     * @param token Address of the token
     * @param from Address from which tokens will be transferred
     * @param to Receipent address of the tokens
     * @param amount Amount of tokens to transfer
     */
    function transferFrom(
        address token,
        address from,
        address to,
        uint256 amount
    ) external override onlyOwner {
        // solhint-disable-next-line avoid-tx-origin
        require(from == tx.origin || from.isContract(), "Invalid from address");

        IERC20(token).safeTransferFrom(from, to, amount);
    }
}

// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;

interface ITokenTransferProxy {
    function transferFrom(
        address token,
        address from,
        address to,
        uint256 amount
    ) external;
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @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, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, 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 (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        return a - b;
    }

    /**
     * @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) {
        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, reverting 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) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: modulo by zero");
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * 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);
        return a - b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * 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;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

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

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

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

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

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/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.
 */
abstract 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 virtual 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;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @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);
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;

        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping (bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) { // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            // When the value to delete is the last one, the swap operation is unnecessary. However, since this occurs
            // so rarely, we still do the swap anyway to avoid the gas cost of adding an 'if' statement.

            bytes32 lastvalue = set._values[lastIndex];

            // Move the last value to the index where the value to delete is
            set._values[toDeleteIndex] = lastvalue;
            // Update the index for the moved value
            set._indexes[lastvalue] = toDeleteIndex + 1; // All indexes are 1-based

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        require(set._values.length > index, "EnumerableSet: index out of bounds");
        return set._values[index];
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }


    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

   /**
    * @dev Returns the value stored at position `index` in the set. O(1).
    *
    * Note that there are no guarantees on the ordering of values inside the
    * array, and it may change when more values are added or removed.
    *
    * Requirements:
    *
    * - `index` must be strictly less than {length}.
    */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/EnumerableSet.sol";
import "../utils/Address.sol";
import "../utils/Context.sol";

/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context {
    using EnumerableSet for EnumerableSet.AddressSet;
    using Address for address;

    struct RoleData {
        EnumerableSet.AddressSet members;
        bytes32 adminRole;
    }

    mapping (bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view returns (bool) {
        return _roles[role].members.contains(account);
    }

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view returns (uint256) {
        return _roles[role].members.length();
    }

    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view returns (address) {
        return _roles[role].members.at(index);
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to grant");

        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual {
        require(hasRole(_roles[role].adminRole, _msgSender()), "AccessControl: sender must be an admin to revoke");

        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        emit RoleAdminChanged(role, _roles[role].adminRole, adminRole);
        _roles[role].adminRole = adminRole;
    }

    function _grantRole(bytes32 role, address account) private {
        if (_roles[role].members.add(account)) {
            emit RoleGranted(role, account, _msgSender());
        }
    }

    function _revokeRole(bytes32 role, address account) private {
        if (_roles[role].members.remove(account)) {
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

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

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

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

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

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

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

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

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

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

// SPDX-License-Identifier: ISC

pragma solidity 0.7.5;
pragma abicoder v2;

import "../Utils.sol";

interface IBalancerV2Vault {
    enum SwapKind {
        GIVEN_IN,
        GIVEN_OUT
    }

    struct SingleSwap {
        bytes32 poolId;
        SwapKind kind;
        address assetIn;
        address assetOut;
        uint256 amount;
        bytes userData;
    }

    struct BatchSwapStep {
        bytes32 poolId;
        uint256 assetInIndex;
        uint256 assetOutIndex;
        uint256 amount;
        bytes userData;
    }

    struct FundManagement {
        address sender;
        bool fromInternalBalance;
        address payable recipient;
        bool toInternalBalance;
    }

    function swap(
        SingleSwap memory singleSwap,
        FundManagement memory funds,
        uint256 limit,
        uint256 deadline
    ) external payable returns (uint256);

    function batchSwap(
        SwapKind kind,
        BatchSwapStep[] memory swaps,
        address[] memory assets,
        FundManagement memory funds,
        int256[] memory limits,
        uint256 deadline
    ) external payable returns (int256[] memory);
}