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pragma solidity ^0.5.17;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/cryptography/ECDSA.sol";
import "@openzeppelin/upgrades/contracts/upgradeability/InitializableAdminUpgradeabilityProxy.sol";

import "../Governance/Claimable.sol";
import "../libraries/String.sol";
import "./RenERC20.sol";
import "./interfaces/IGateway.sol";
import "../libraries/CanReclaimTokens.sol";
import "./MintGatewayV1.sol";

contract MintGatewayStateV2 {
    struct Burn {
        uint256 _blocknumber;
        bytes _to;
        uint256 _amount;
        // Optional
        string _chain;
        bytes _payload;
    }

    mapping(uint256 => Burn) internal burns;

    bytes32 public selectorHash;

    // Initialize to 0x1 because 0x0 is the default value returned by `recover`
    // when it encounters an error.
    address public _legacy_mintAuthority;
}

/// @notice Gateway handles verifying mint and burn requests. A mintAuthority
/// approves new assets to be minted by providing a digital signature. An owner
/// of an asset can request for it to be burnt.
contract MintGatewayLogicV2 is
    Initializable,
    Claimable,
    CanReclaimTokens,
    IGateway,
    MintGatewayStateV1,
    MintGatewayStateV2
{
    using SafeMath for uint256;

    event LogMintAuthorityUpdated(address indexed _newMintAuthority);
    event LogMint(
        address indexed _to,
        uint256 _amount,
        uint256 indexed _n,
        // Log the nHash instead of sHash so that it can be queried without
        // knowing the sHash.
        bytes32 indexed _nHash
    );
    event LogBurn(
        bytes _to,
        uint256 _amount,
        uint256 indexed _n,
        bytes indexed _indexedTo
    );

    /// @notice Only allow the Darknode Payment contract.
    modifier onlyOwnerOrMintAuthority() {
        require(
            msg.sender == mintAuthority || msg.sender == owner(),
            "MintGateway: caller is not the owner or mint authority"
        );
        _;
    }

    /// @param _token The RenERC20 this Gateway is responsible for.
    /// @param _feeRecipient The recipient of burning and minting fees.
    /// @param _mintAuthority The address of the key that can sign mint
    ///        requests.
    /// @param _mintFee The amount subtracted each mint request and
    ///        forwarded to the feeRecipient. In BIPS.
    /// @param _burnFee The amount subtracted each burn request and
    ///        forwarded to the feeRecipient. In BIPS.
    function initialize(
        RenERC20LogicV1 _token,
        address _feeRecipient,
        address _mintAuthority,
        uint16 _mintFee,
        uint16 _burnFee,
        uint256 _minimumBurnAmount
    ) public initializer {
        Claimable.initialize(msg.sender);
        CanReclaimTokens.initialize(msg.sender);
        minimumBurnAmount = _minimumBurnAmount;
        token = _token;
        mintFee = _mintFee;
        burnFee = _burnFee;
        updateMintAuthority(_mintAuthority);
        updateFeeRecipient(_feeRecipient);
    }

    /// @param _selectorHash Hash of the token and chain selector.
    ///        The hash should calculated from
    ///        `SHA256(4 bytes of selector length, selector)`
    function updateSelectorHash(bytes32 _selectorHash) public onlyOwner {
        selectorHash = _selectorHash;
    }

    /// @notice Allow the owner to update the token symbol.
    function updateSymbol(string memory symbol) public onlyOwner {
        token.updateSymbol(symbol);
    }

    // Public functions ////////////////////////////////////////////////////////

    /// @notice Claims ownership of the token passed in to the constructor.
    /// `transferStoreOwnership` must have previously been called.
    /// Anyone can call this function.
    function claimTokenOwnership() public {
        token.claimOwnership();
    }

    /// @notice Allow the owner to update the owner of the RenERC20 token.
    function transferTokenOwnership(MintGatewayLogicV2 _nextTokenOwner)
        public
        onlyOwner
    {
        token.transferOwnership(address(_nextTokenOwner));
        _nextTokenOwner.claimTokenOwnership();
    }

    /// @notice Allow the owner to update the mint authority.
    ///
    /// @param _nextMintAuthority The new mint authority address.
    function updateMintAuthority(address _nextMintAuthority)
        public
        onlyOwnerOrMintAuthority
    {
        // The mint authority should not be set to 0, which is the result
        // returned by ecrecover for an invalid signature.
        require(
            _nextMintAuthority != address(0),
            "MintGateway: mintAuthority cannot be set to address zero"
        );
        mintAuthority = _nextMintAuthority;
        emit LogMintAuthorityUpdated(mintAuthority);
    }

    /// @notice Allow the owner to update the legacy mint authority.
    ///
    /// @param _nextMintAuthority The new legacy mint authority address.
    function _legacy_updateMintAuthority(address _nextMintAuthority)
        public
        onlyOwner
    {
        _legacy_mintAuthority = _nextMintAuthority;
    }

    /// @notice Allow the owner to update the minimum burn amount.
    ///
    /// @param _minimumBurnAmount The new min burn amount.
    function updateMinimumBurnAmount(uint256 _minimumBurnAmount)
        public
        onlyOwner
    {
        minimumBurnAmount = _minimumBurnAmount;
    }

    /// @notice Allow the owner to update the fee recipient.
    ///
    /// @param _nextFeeRecipient The address to start paying fees to.
    function updateFeeRecipient(address _nextFeeRecipient) public onlyOwner {
        // 'mint' and 'burn' will fail if the feeRecipient is 0x0
        require(
            _nextFeeRecipient != address(0x0),
            "MintGateway: fee recipient cannot be 0x0"
        );

        feeRecipient = _nextFeeRecipient;
    }

    /// @notice Allow the owner to update the 'mint' fee.
    ///
    /// @param _nextMintFee The new fee for minting and burning.
    function updateMintFee(uint16 _nextMintFee) public onlyOwner {
        mintFee = _nextMintFee;
    }

    /// @notice Allow the owner to update the burn fee.
    ///
    /// @param _nextBurnFee The new fee for minting and burning.
    function updateBurnFee(uint16 _nextBurnFee) public onlyOwner {
        burnFee = _nextBurnFee;
    }

    /// @notice mint verifies a mint approval signature from RenVM and creates
    ///         tokens after taking a fee for the `_feeRecipient`.
    ///
    /// @param _pHash (payload hash) The hash of the payload associated with the
    ///        mint.
    /// @param _amountUnderlying The amount of the token being minted, in its smallest
    ///        value. (e.g. satoshis for BTC).
    /// @param _nHash (nonce hash) The hash of the nonce, amount and pHash.
    /// @param _sig The signature of the hash of the following values:
    ///        (pHash, amount, msg.sender, nHash), signed by the mintAuthority.
    function mint(
        bytes32 _pHash,
        uint256 _amountUnderlying,
        bytes32 _nHash,
        bytes memory _sig
    ) public returns (uint256) {
        // Calculate the hash signed by RenVM.
        bytes32 sigHash =
            hashForSignature(_pHash, _amountUnderlying, msg.sender, _nHash);

        // Calculate the v0.2 signature hash for backwards-compatibility.
        bytes32 legacySigHash =
            _legacy_hashForSignature(
                _pHash,
                _amountUnderlying,
                msg.sender,
                _nHash
            );

        // Check that neither signature has been redeemed.
        require(
            status[sigHash] == false && status[legacySigHash] == false,
            "MintGateway: nonce hash already spent"
        );

        // If both signatures fail verification, throw an error. If any one of
        // them passed the verification, continue.
        if (
            !verifySignature(sigHash, _sig) &&
            !_legacy_verifySignature(legacySigHash, _sig)
        ) {
            // Return a detailed string containing the hash and recovered
            // signer. This is somewhat costly but is only run in the revert
            // branch.
            revert(
                String.add8(
                    "MintGateway: invalid signature. pHash: ",
                    String.fromBytes32(_pHash),
                    ", amount: ",
                    String.fromUint(_amountUnderlying),
                    ", msg.sender: ",
                    String.fromAddress(msg.sender),
                    ", _nHash: ",
                    String.fromBytes32(_nHash)
                )
            );
        }

        // Update the status for both signature hashes. This is to ensure that
        // legacy signatures can't be re-redeemed if `updateSelectorHash` is
        // ever called - thus changing the result of `sigHash` but not
        // `legacySigHash`.
        status[sigHash] = true;
        status[legacySigHash] = true;

        uint256 amountScaled = token.fromUnderlying(_amountUnderlying);

        // Mint `amount - fee` for the recipient and mint `fee` for the minter
        uint256 absoluteFeeScaled =
            amountScaled.mul(mintFee).div(BIPS_DENOMINATOR);
        uint256 receivedAmountScaled =
            amountScaled.sub(
                absoluteFeeScaled,
                "MintGateway: fee exceeds amount"
            );

        // Mint amount minus the fee
        token.mint(msg.sender, receivedAmountScaled);
        // Mint the fee
        if (absoluteFeeScaled > 0) {
            token.mint(feeRecipient, absoluteFeeScaled);
        }

        // Emit a log with a unique identifier 'n'.
        uint256 receivedAmountUnderlying =
            token.toUnderlying(receivedAmountScaled);
        emit LogMint(msg.sender, receivedAmountUnderlying, nextN, _nHash);
        nextN += 1;

        return receivedAmountScaled;
    }

    /// @notice burn destroys tokens after taking a fee for the `_feeRecipient`,
    ///         allowing the associated assets to be released on their native
    ///         chain.
    ///
    /// @param _to The address to receive the un-bridged asset. The format of
    ///        this address should be of the destination chain.
    ///        For example, when burning to Bitcoin, _to should be a
    ///        Bitcoin address.
    /// @param _amount The amount of the token being burnt, in its
    ///        smallest value. (e.g. satoshis for BTC)
    function burn(bytes memory _to, uint256 _amount) public returns (uint256) {
        // The recipient must not be empty. Better validation is possible,
        // but would need to be customized for each destination ledger.
        require(_to.length != 0, "MintGateway: to address is empty");

        // Calculate fee, subtract it from amount being burnt.
        uint256 fee = _amount.mul(burnFee).div(BIPS_DENOMINATOR);
        uint256 amountAfterFee =
            _amount.sub(fee, "MintGateway: fee exceeds amount");

        // If the scaled token can represent more precision than the underlying
        // token, the difference is lost. This won't exceed 1 sat, so is
        // negligible compared to burning and transaction fees.
        uint256 amountAfterFeeUnderlying = token.toUnderlying(amountAfterFee);

        // Burn the whole amount, and then re-mint the fee.
        token.burn(msg.sender, _amount);
        if (fee > 0) {
            token.mint(feeRecipient, fee);
        }

        require(
            // Must be strictly greater, to that the release transaction is of
            // at least one unit.
            amountAfterFeeUnderlying > minimumBurnAmount,
            "MintGateway: amount is less than the minimum burn amount"
        );

        emit LogBurn(_to, amountAfterFeeUnderlying, nextN, _to);

        // Store burn so that it can be looked up instead of relying on event
        // logs.
        bytes memory payload;
        MintGatewayStateV2.burns[nextN] = Burn({
            _blocknumber: block.number,
            _to: _to,
            _amount: amountAfterFeeUnderlying,
            _chain: "",
            _payload: payload
        });

        nextN += 1;

        return amountAfterFeeUnderlying;
    }

    function getBurn(uint256 _n)
        public
        view
        returns (
            uint256 _blocknumber,
            bytes memory _to,
            uint256 _amount,
            // Optional
            string memory _chain,
            bytes memory _payload
        )
    {
        Burn memory burnStruct = MintGatewayStateV2.burns[_n];
        require(burnStruct._to.length > 0, "MintGateway: burn not found");
        return (
            burnStruct._blocknumber,
            burnStruct._to,
            burnStruct._amount,
            burnStruct._chain,
            burnStruct._payload
        );
    }

    /// @notice verifySignature checks the the provided signature matches the
    /// provided parameters.
    function verifySignature(bytes32 _sigHash, bytes memory _sig)
        public
        view
        returns (bool)
    {
        return mintAuthority == ECDSA.recover(_sigHash, _sig);
    }

    /// @notice verifySignature checks the the provided signature matches the
    /// provided parameters.
    function _legacy_verifySignature(bytes32 _sigHash, bytes memory _sig)
        public
        view
        returns (bool)
    {
        require(
            _legacy_mintAuthority != address(0x0),
            "MintGateway: legacy mintAuthority not set"
        );
        return _legacy_mintAuthority == ECDSA.recover(_sigHash, _sig);
    }

    /// @notice hashForSignature hashes the parameters so that they can be
    /// signed.
    function hashForSignature(
        bytes32 _pHash,
        uint256 _amount,
        address _to,
        bytes32 _nHash
    ) public view returns (bytes32) {
        return
            keccak256(abi.encode(_pHash, _amount, selectorHash, _to, _nHash));
    }

    /// @notice _legacy_hashForSignature calculates the signature hash used by
    /// the 0.2 version of RenVM. It's kept here for backwards-compatibility.
    function _legacy_hashForSignature(
        bytes32 _pHash,
        uint256 _amount,
        address _to,
        bytes32 _nHash
    ) public view returns (bytes32) {
        return
            keccak256(abi.encode(_pHash, _amount, address(token), _to, _nHash));
    }
}

/* solium-disable-next-line no-empty-blocks */
contract MintGatewayProxy is InitializableAdminUpgradeabilityProxy {

}

pragma solidity ^0.5.17;

import "./Gateway/MintGatewayV2.sol";
import "./Gateway/GatewayRegistry.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/StandaloneERC20.sol";

/// @notice Bindings imports all of the contracts for generating bindings.
/* solium-disable-next-line no-empty-blocks */
contract Bindings {

}

pragma solidity ^0.5.17;

import "../Governance/Claimable.sol";
import "./RenERC20.sol";
import "../libraries/LinkedList.sol";
import "./interfaces/IGateway.sol";
import "../libraries/CanReclaimTokens.sol";

/// @notice GatewayRegistry is a mapping from assets to their associated
/// RenERC20 and Gateway contracts.
contract GatewayRegistry is Claimable, CanReclaimTokens {
    constructor() public {
        Claimable.initialize(msg.sender);
        CanReclaimTokens.initialize(msg.sender);
    }

    /// @dev The symbol is included twice because strings have to be hashed
    /// first in order to be used as a log index/topic.
    event LogGatewayRegistered(
        string _symbol,
        string indexed _indexedSymbol,
        address indexed _token,
        address indexed _gatewayContract
    );
    event LogGatewayDeregistered(
        string _symbol,
        string indexed _indexedSymbol,
        address indexed _token,
        address indexed _gatewayContract
    );
    event LogGatewayUpdated(
        address indexed _token,
        address indexed _currentGatewayContract,
        address indexed _newGatewayContract
    );

    /// @notice The number of gateways registered.
    uint256 numGatewayContracts = 0;

    /// @notice A list of gateway contracts.
    LinkedList.List private gatewayContractList;

    /// @notice A list of ren token contracts.
    LinkedList.List private renTokenList;

    /// @notice A map of token addresses to canonical gateway contract addresses.
    mapping(address => address) private gatewayByToken;

    /// @notice A map of token symbols to token addresses.
    mapping(string => address) private tokenBySymbol;

    /// @notice Allow the owner to set the Gateway contract for a given
    ///         RenERC20 token contract.
    ///
    /// @param _token The address of the RenERC20 token contract.
    /// @param _gatewayContract The address of the Gateway contract.
    function setGateway(
        string calldata _symbol,
        address _token,
        address _gatewayContract
    ) external onlyOwner {
        require(
            symbolIsValid(_symbol),
            "GatewayRegistry: symbol must be alphanumeric"
        );

        // Check that token, Gateway and symbol haven't already been registered.
        require(
            !LinkedList.isInList(gatewayContractList, _gatewayContract),
            "GatewayRegistry: gateway already registered"
        );
        require(
            gatewayByToken[_token] == address(0x0),
            "GatewayRegistry: token already registered"
        );
        require(
            tokenBySymbol[_symbol] == address(0x0),
            "GatewayRegistry: symbol already registered"
        );

        // Add to list of gateways.
        LinkedList.append(gatewayContractList, _gatewayContract);

        // Add to list of ren tokens.
        LinkedList.append(renTokenList, _token);

        tokenBySymbol[_symbol] = _token;
        gatewayByToken[_token] = _gatewayContract;
        numGatewayContracts += 1;

        emit LogGatewayRegistered(_symbol, _symbol, _token, _gatewayContract);
    }

    /// @notice Allow the owner to update the Gateway contract for a given
    ///         RenERC20 contract.
    ///
    /// @param _token The address of the RenERC20 contract.
    /// @param _newGatewayContract The updated address of the Gateway contract.
    function updateGateway(address _token, address _newGatewayContract)
        external
        onlyOwner
    {
        // Check that token, Gateway are registered
        address currentGateway = gatewayByToken[_token];
        require(
            currentGateway != address(0x0),
            "GatewayRegistry: token not registered"
        );

        // Remove to list of Gateway contracts.
        LinkedList.remove(gatewayContractList, currentGateway);

        // Add to list of RenERC20 tokens.
        LinkedList.append(gatewayContractList, _newGatewayContract);

        gatewayByToken[_token] = _newGatewayContract;

        emit LogGatewayUpdated(_token, currentGateway, _newGatewayContract);
    }

    /// @notice Allows the owner to remove the Gateway contract for a given
    ///         RenERC20 contract.
    ///
    /// @param _symbol The symbol of the token to deregister.
    function removeGateway(string calldata _symbol) external onlyOwner {
        // Look up token address
        address tokenAddress = tokenBySymbol[_symbol];
        require(
            tokenAddress != address(0x0),
            "GatewayRegistry: symbol not registered"
        );

        // Look up Gateway contract address
        address gatewayAddress = gatewayByToken[tokenAddress];

        // Remove token and Gateway contract
        delete gatewayByToken[tokenAddress];
        delete tokenBySymbol[_symbol];
        LinkedList.remove(gatewayContractList, gatewayAddress);
        LinkedList.remove(renTokenList, tokenAddress);
        numGatewayContracts -= 1;

        emit LogGatewayDeregistered(
            _symbol,
            _symbol,
            tokenAddress,
            gatewayAddress
        );
    }

    /// @dev To get all the registered Gateway contracts use count = 0.
    function getGateways(address _start, uint256 _count)
        external
        view
        returns (address[] memory)
    {
        return
            LinkedList.elements(
                gatewayContractList,
                _start,
                _count == 0 ? numGatewayContracts : _count
            );
    }

    /// @dev To get all the registered RenERC20 tokens use count = 0.
    function getRenTokens(address _start, uint256 _count)
        external
        view
        returns (address[] memory)
    {
        return
            LinkedList.elements(
                renTokenList,
                _start,
                _count == 0 ? numGatewayContracts : _count
            );
    }

    /// @notice Returns the Gateway contract for the given RenERC20 token
    ///         address.
    ///
    /// @param _token The address of the RenERC20 token contract.
    function getGatewayByToken(address _token)
        external
        view
        returns (IGateway)
    {
        return IGateway(gatewayByToken[_token]);
    }

    /// @notice Returns the Gateway contract for the given RenERC20 token
    ///         symbol.
    ///
    /// @param _tokenSymbol The symbol of the RenERC20 token contract.
    function getGatewayBySymbol(string calldata _tokenSymbol)
        external
        view
        returns (IGateway)
    {
        return IGateway(gatewayByToken[tokenBySymbol[_tokenSymbol]]);
    }

    /// @notice Returns the RenERC20 address for the given token symbol.
    ///
    /// @param _tokenSymbol The symbol of the RenERC20 token contract to
    ///        lookup.
    function getTokenBySymbol(string calldata _tokenSymbol)
        external
        view
        returns (IERC20)
    {
        return IERC20(tokenBySymbol[_tokenSymbol]);
    }

    function symbolIsValid(string memory _tokenSymbol)
        public
        pure
        returns (bool)
    {
        for (uint256 i = 0; i < bytes(_tokenSymbol).length; i++) {
            uint8 char = uint8(bytes(_tokenSymbol)[i]);
            if (
                !((char >= 65 && char <= 90) ||
                    (char >= 97 && char <= 122) ||
                    (char >= 48 && char <= 57))
            ) {
                return false;
            }
        }
        return true;
    }
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "./ERC20Detailed.sol";
import "./ERC20Mintable.sol";
import "./ERC20Pausable.sol";


/**
 * @title Standard ERC20 token, with minting and pause functionality.
 *
 */
contract StandaloneERC20 is Initializable, ERC20Detailed, ERC20Mintable, ERC20Pausable {
    function initialize(
        string memory name, string memory symbol, uint8 decimals, uint256 initialSupply, address initialHolder,
        address[] memory minters, address[] memory pausers
    ) public initializer {
        ERC20Detailed.initialize(name, symbol, decimals);

        // Mint the initial supply
        _mint(initialHolder, initialSupply);

        // Initialize the minter and pauser roles, and renounce them
        ERC20Mintable.initialize(address(this));
        _removeMinter(address(this));

        ERC20Pausable.initialize(address(this));
        _removePauser(address(this));

        // Add the requested minters and pausers (this can be done after renouncing since
        // these are the internal calls)
        for (uint256 i = 0; i < minters.length; ++i) {
            _addMinter(minters[i]);
        }

        for (uint256 i = 0; i < pausers.length; ++i) {
            _addPauser(pausers[i]);
        }
    }

    function initialize(
        string memory name, string memory symbol, uint8 decimals, address[] memory minters, address[] memory pausers
    ) public initializer {
        ERC20Detailed.initialize(name, symbol, decimals);

        // Initialize the minter and pauser roles, and renounce them
        ERC20Mintable.initialize(address(this));
        _removeMinter(address(this));

        ERC20Pausable.initialize(address(this));
        _removePauser(address(this));

        // Add the requested minters and pausers (this can be done after renouncing since
        // these are the internal calls)
        for (uint256 i = 0; i < minters.length; ++i) {
            _addMinter(minters[i]);
        }

        for (uint256 i = 0; i < pausers.length; ++i) {
            _addPauser(pausers[i]);
        }
    }
}

pragma solidity >=0.4.24 <0.7.0;


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

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

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

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

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

    _;

    if (isTopLevelCall) {
      initializing = false;
    }
  }

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

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

pragma solidity ^0.5.0;

/**
 * @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.
     *
     * _Available since v2.4.0._
     */
    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.
     *
     * _Available since v2.4.0._
     */
    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.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

pragma solidity ^0.5.0;

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * NOTE: This call _does not revert_ if the signature is invalid, or
     * if the signer is otherwise unable to be retrieved. In those scenarios,
     * the zero address is returned.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        // Check the signature length
        if (signature.length != 65) {
            revert("ECDSA: signature length is invalid");
        }

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

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

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

        if (v != 27 && v != 28) {
            revert("ECDSA: signature.v is in the wrong range");
        }

        // If the signature is valid (and not malleable), return the signer address
        return ecrecover(hash, v, r, s);
    }

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

pragma solidity ^0.5.0;

import './BaseAdminUpgradeabilityProxy.sol';
import './InitializableUpgradeabilityProxy.sol';

/**
 * @title InitializableAdminUpgradeabilityProxy
 * @dev Extends from BaseAdminUpgradeabilityProxy with an initializer for 
 * initializing the implementation, admin, and init data.
 */
contract InitializableAdminUpgradeabilityProxy is BaseAdminUpgradeabilityProxy, InitializableUpgradeabilityProxy {
  /**
   * Contract initializer.
   * @param _logic address of the initial implementation.
   * @param _admin Address of the proxy administrator.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  function initialize(address _logic, address _admin, bytes memory _data) public payable {
    require(_implementation() == address(0));
    InitializableUpgradeabilityProxy.initialize(_logic, _data);
    assert(ADMIN_SLOT == bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1));
    _setAdmin(_admin);
  }
}

pragma solidity ^0.5.17;

import "@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol";
import "@openzeppelin/upgrades/contracts/Initializable.sol";

/**
 * @title Claimable
 * @dev Extension for the Ownable contract, where the ownership needs to be claimed.
 * This allows the new owner to accept the transfer.
 */
contract Claimable is Initializable, Ownable {
    address public pendingOwner;

    function initialize(address _nextOwner) public initializer {
        Ownable.initialize(_nextOwner);
    }

    modifier onlyPendingOwner() {
        require(
            _msgSender() == pendingOwner,
            "Claimable: caller is not the pending owner"
        );
        _;
    }

    function transferOwnership(address newOwner) public onlyOwner {
        require(
            newOwner != owner() && newOwner != pendingOwner,
            "Claimable: invalid new owner"
        );
        pendingOwner = newOwner;
    }

    // Allow skipping two-step transfer if the recipient is known to be a valid
    // owner, for use in smart-contracts only.
    function _directTransferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    function claimOwnership() public onlyPendingOwner {
        _transferOwnership(pendingOwner);
        delete pendingOwner;
    }
}

pragma solidity ^0.5.17;

library String {
    /// @notice Convert a uint value to its decimal string representation
    // solium-disable-next-line security/no-assign-params
    function fromUint(uint256 _i) internal pure returns (string memory) {
        if (_i == 0) {
            return "0";
        }
        uint256 j = _i;
        uint256 len;
        while (j != 0) {
            len++;
            j /= 10;
        }
        bytes memory bstr = new bytes(len);
        uint256 k = len - 1;
        while (_i != 0) {
            bstr[k--] = bytes1(uint8(48 + (_i % 10)));
            _i /= 10;
        }
        return string(bstr);
    }

    /// @notice Convert a bytes32 value to its hex string representation.
    function fromBytes32(bytes32 _value) internal pure returns (string memory) {
        bytes memory alphabet = "0123456789abcdef";

        bytes memory str = new bytes(32 * 2 + 2);
        str[0] = "0";
        str[1] = "x";
        for (uint256 i = 0; i < 32; i++) {
            str[2 + i * 2] = alphabet[uint256(uint8(_value[i] >> 4))];
            str[3 + i * 2] = alphabet[uint256(uint8(_value[i] & 0x0f))];
        }
        return string(str);
    }

    /// @notice Convert an address to its hex string representation.
    function fromAddress(address _addr) internal pure returns (string memory) {
        bytes32 value = bytes32(uint256(_addr));
        bytes memory alphabet = "0123456789abcdef";

        bytes memory str = new bytes(20 * 2 + 2);
        str[0] = "0";
        str[1] = "x";
        for (uint256 i = 0; i < 20; i++) {
            str[2 + i * 2] = alphabet[uint256(uint8(value[i + 12] >> 4))];
            str[3 + i * 2] = alphabet[uint256(uint8(value[i + 12] & 0x0f))];
        }
        return string(str);
    }

    /// @notice Append eight strings.
    function add8(
        string memory a,
        string memory b,
        string memory c,
        string memory d,
        string memory e,
        string memory f,
        string memory g,
        string memory h
    ) internal pure returns (string memory) {
        return string(abi.encodePacked(a, b, c, d, e, f, g, h));
    }
}

pragma solidity ^0.5.16;

import "@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol";
import "@openzeppelin/upgrades/contracts/upgradeability/InitializableAdminUpgradeabilityProxy.sol";
import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20Detailed.sol";

import "../Governance/Claimable.sol";
import "../libraries/CanReclaimTokens.sol";
import "./ERC20WithRate.sol";
import "./ERC20WithPermit.sol";

/// @notice RenERC20 represents a digital asset that has been bridged on to
/// the Ethereum ledger. It exposes mint and burn functions that can only be
/// called by it's associated Gateway contract.
contract RenERC20LogicV1 is
    Initializable,
    ERC20,
    ERC20Detailed,
    ERC20WithRate,
    ERC20WithPermit,
    Claimable,
    CanReclaimTokens
{
    /* solium-disable-next-line no-empty-blocks */
    function initialize(
        uint256 _chainId,
        address _nextOwner,
        uint256 _initialRate,
        string memory _version,
        string memory _name,
        string memory _symbol,
        uint8 _decimals
    ) public initializer {
        ERC20Detailed.initialize(_name, _symbol, _decimals);
        ERC20WithRate.initialize(_nextOwner, _initialRate);
        ERC20WithPermit.initialize(
            _chainId,
            _version,
            _name,
            _symbol,
            _decimals
        );
        Claimable.initialize(_nextOwner);
        CanReclaimTokens.initialize(_nextOwner);
    }

    function updateSymbol(string memory symbol) public onlyOwner {
        ERC20Detailed._symbol = symbol;
    }

    /// @notice mint can only be called by the tokens' associated Gateway
    /// contract. See Gateway's mint function instead.
    function mint(address _to, uint256 _amount) public onlyOwner {
        _mint(_to, _amount);
    }

    /// @notice burn can only be called by the tokens' associated Gateway
    /// contract. See Gateway's burn functions instead.
    function burn(address _from, uint256 _amount) public onlyOwner {
        _burn(_from, _amount);
    }

    function transfer(address recipient, uint256 amount) public returns (bool) {
        // Disallow sending tokens to the ERC20 contract address - a common
        // mistake caused by the Ethereum transaction's `to` needing to be
        // the token's address.
        require(
            recipient != address(this),
            "RenERC20: can't transfer to token address"
        );
        return super.transfer(recipient, amount);
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public returns (bool) {
        // Disallow sending tokens to the ERC20 contract address (see comment
        // in `transfer`).
        require(
            recipient != address(this),
            "RenERC20: can't transfer to token address"
        );
        return super.transferFrom(sender, recipient, amount);
    }
}

/* solium-disable-next-line no-empty-blocks */
contract RenERC20Proxy is InitializableAdminUpgradeabilityProxy {

}

pragma solidity ^0.5.17;

interface IMintGateway {
    function mint(
        bytes32 _pHash,
        uint256 _amount,
        bytes32 _nHash,
        bytes calldata _sig
    ) external returns (uint256);

    function mintFee() external view returns (uint256);
}

interface IBurnGateway {
    function burn(bytes calldata _to, uint256 _amountScaled)
        external
        returns (uint256);

    function burnFee() external view returns (uint256);
}

// TODO: In ^0.6.0, should be `interface IGateway is IMintGateway,IBurnGateway {}`
interface IGateway {
    // is IMintGateway
    function mint(
        bytes32 _pHash,
        uint256 _amount,
        bytes32 _nHash,
        bytes calldata _sig
    ) external returns (uint256);

    function mintFee() external view returns (uint256);

    // is IBurnGateway
    function burn(bytes calldata _to, uint256 _amountScaled)
        external
        returns (uint256);

    function burnFee() external view returns (uint256);
}

pragma solidity ^0.5.17;

import "@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/SafeERC20.sol";
import "@openzeppelin/upgrades/contracts/Initializable.sol";

import "../Governance/Claimable.sol";

contract CanReclaimTokens is Claimable {
    using SafeERC20 for ERC20;

    mapping(address => bool) private recoverableTokensBlacklist;

    function initialize(address _nextOwner) public initializer {
        Claimable.initialize(_nextOwner);
    }

    function blacklistRecoverableToken(address _token) public onlyOwner {
        recoverableTokensBlacklist[_token] = true;
    }

    /// @notice Allow the owner of the contract to recover funds accidentally
    /// sent to the contract. To withdraw ETH, the token should be set to `0x0`.
    function recoverTokens(address _token) external onlyOwner {
        require(
            !recoverableTokensBlacklist[_token],
            "CanReclaimTokens: token is not recoverable"
        );

        if (_token == address(0x0)) {
            msg.sender.transfer(address(this).balance);
        } else {
            ERC20(_token).safeTransfer(
                msg.sender,
                ERC20(_token).balanceOf(address(this))
            );
        }
    }
}

pragma solidity 0.5.17;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/cryptography/ECDSA.sol";
import "@openzeppelin/upgrades/contracts/upgradeability/InitializableAdminUpgradeabilityProxy.sol";

import "../Governance/Claimable.sol";
import "../libraries/String.sol";
import "./RenERC20.sol";
import "./interfaces/IGateway.sol";
import "../libraries/CanReclaimTokens.sol";

contract MintGatewayStateV1 {
    uint256 constant BIPS_DENOMINATOR = 10000;
    uint256 public minimumBurnAmount;

    /// @notice Each Gateway is tied to a specific RenERC20 token.
    RenERC20LogicV1 public token;

    /// @notice The mintAuthority is an address that can sign mint requests.
    address public mintAuthority;

    /// @dev feeRecipient is assumed to be an address (or a contract) that can
    /// accept erc20 payments it cannot be 0x0.
    /// @notice When tokens are mint or burnt, a portion of the tokens are
    /// forwarded to a fee recipient.
    address public feeRecipient;

    /// @notice The mint fee in bips.
    uint16 public mintFee;

    /// @notice The burn fee in bips.
    uint16 public burnFee;

    /// @notice Each signature can only be seen once.
    mapping(bytes32 => bool) public status;

    // LogMint and LogBurn contain a unique `n` that identifies
    // the mint or burn event.
    uint256 public nextN = 0;
}

/// @notice Gateway handles verifying mint and burn requests. A mintAuthority
/// approves new assets to be minted by providing a digital signature. An owner
/// of an asset can request for it to be burnt.
contract MintGatewayLogicV1 is
    Initializable,
    Claimable,
    CanReclaimTokens,
    IGateway,
    MintGatewayStateV1
{
    using SafeMath for uint256;

    event LogMintAuthorityUpdated(address indexed _newMintAuthority);
    event LogMint(
        address indexed _to,
        uint256 _amount,
        uint256 indexed _n,
        bytes32 indexed _signedMessageHash
    );
    event LogBurn(
        bytes _to,
        uint256 _amount,
        uint256 indexed _n,
        bytes indexed _indexedTo
    );

    /// @notice Only allow the Darknode Payment contract.
    modifier onlyOwnerOrMintAuthority() {
        require(
            msg.sender == mintAuthority || msg.sender == owner(),
            "Gateway: caller is not the owner or mint authority"
        );
        _;
    }

    /// @param _token The RenERC20 this Gateway is responsible for.
    /// @param _feeRecipient The recipient of burning and minting fees.
    /// @param _mintAuthority The address of the key that can sign mint
    ///        requests.
    /// @param _mintFee The amount subtracted each mint request and
    ///        forwarded to the feeRecipient. In BIPS.
    /// @param _burnFee The amount subtracted each burn request and
    ///        forwarded to the feeRecipient. In BIPS.
    function initialize(
        RenERC20LogicV1 _token,
        address _feeRecipient,
        address _mintAuthority,
        uint16 _mintFee,
        uint16 _burnFee,
        uint256 _minimumBurnAmount
    ) public initializer {
        Claimable.initialize(msg.sender);
        CanReclaimTokens.initialize(msg.sender);
        minimumBurnAmount = _minimumBurnAmount;
        token = _token;
        mintFee = _mintFee;
        burnFee = _burnFee;
        updateMintAuthority(_mintAuthority);
        updateFeeRecipient(_feeRecipient);
    }

    // Public functions ////////////////////////////////////////////////////////

    /// @notice Claims ownership of the token passed in to the constructor.
    /// `transferStoreOwnership` must have previously been called.
    /// Anyone can call this function.
    function claimTokenOwnership() public {
        token.claimOwnership();
    }

    /// @notice Allow the owner to update the owner of the RenERC20 token.
    function transferTokenOwnership(MintGatewayLogicV1 _nextTokenOwner)
        public
        onlyOwner
    {
        token.transferOwnership(address(_nextTokenOwner));
        _nextTokenOwner.claimTokenOwnership();
    }

    /// @notice Allow the owner to update the mint authority.
    ///
    /// @param _nextMintAuthority The new mint authority address.
    function updateMintAuthority(address _nextMintAuthority)
        public
        onlyOwnerOrMintAuthority
    {
        // The mint authority should not be set to 0, which is the result
        // returned by ecrecover for an invalid signature.
        require(
            _nextMintAuthority != address(0),
            "Gateway: mintAuthority cannot be set to address zero"
        );
        mintAuthority = _nextMintAuthority;
        emit LogMintAuthorityUpdated(mintAuthority);
    }

    /// @notice Allow the owner to update the minimum burn amount.
    ///
    /// @param _minimumBurnAmount The new min burn amount.
    function updateMinimumBurnAmount(uint256 _minimumBurnAmount)
        public
        onlyOwner
    {
        minimumBurnAmount = _minimumBurnAmount;
    }

    /// @notice Allow the owner to update the fee recipient.
    ///
    /// @param _nextFeeRecipient The address to start paying fees to.
    function updateFeeRecipient(address _nextFeeRecipient) public onlyOwner {
        // 'mint' and 'burn' will fail if the feeRecipient is 0x0
        require(
            _nextFeeRecipient != address(0x0),
            "Gateway: fee recipient cannot be 0x0"
        );

        feeRecipient = _nextFeeRecipient;
    }

    /// @notice Allow the owner to update the 'mint' fee.
    ///
    /// @param _nextMintFee The new fee for minting and burning.
    function updateMintFee(uint16 _nextMintFee) public onlyOwner {
        mintFee = _nextMintFee;
    }

    /// @notice Allow the owner to update the burn fee.
    ///
    /// @param _nextBurnFee The new fee for minting and burning.
    function updateBurnFee(uint16 _nextBurnFee) public onlyOwner {
        burnFee = _nextBurnFee;
    }

    /// @notice mint verifies a mint approval signature from RenVM and creates
    ///         tokens after taking a fee for the `_feeRecipient`.
    ///
    /// @param _pHash (payload hash) The hash of the payload associated with the
    ///        mint.
    /// @param _amountUnderlying The amount of the token being minted, in its smallest
    ///        value. (e.g. satoshis for BTC).
    /// @param _nHash (nonce hash) The hash of the nonce, amount and pHash.
    /// @param _sig The signature of the hash of the following values:
    ///        (pHash, amount, msg.sender, nHash), signed by the mintAuthority.
    function mint(
        bytes32 _pHash,
        uint256 _amountUnderlying,
        bytes32 _nHash,
        bytes memory _sig
    ) public returns (uint256) {
        // Calculate the hash signed by RenVM.
        bytes32 sigHash =
            hashForSignature(_pHash, _amountUnderlying, msg.sender, _nHash);

        //

        // Check that the signature hasn't been redeemed.
        require(status[sigHash] == false, "Gateway: nonce hash already spent");

        // If the signature fails verification, throw an error. If any one of
        // them passed the verification, continue.
        if (!verifySignature(sigHash, _sig)) {
            // Return a detailed string containing the hash and recovered
            // signer. This is somewhat costly but is only run in the revert
            // branch.
            revert(
                String.add8(
                    "Gateway: invalid signature. pHash: ",
                    String.fromBytes32(_pHash),
                    ", amount: ",
                    String.fromUint(_amountUnderlying),
                    ", msg.sender: ",
                    String.fromAddress(msg.sender),
                    ", _nHash: ",
                    String.fromBytes32(_nHash)
                )
            );
        }

        // Update the status for the signature hash so that it can't be used
        // again.
        status[sigHash] = true;

        uint256 amountScaled = token.fromUnderlying(_amountUnderlying);

        // Mint `amount - fee` for the recipient and mint `fee` for the minter
        uint256 absoluteFeeScaled =
            amountScaled.mul(mintFee).div(BIPS_DENOMINATOR);
        uint256 receivedAmountScaled =
            amountScaled.sub(absoluteFeeScaled, "Gateway: fee exceeds amount");

        // Mint amount minus the fee
        token.mint(msg.sender, receivedAmountScaled);
        // Mint the fee
        token.mint(feeRecipient, absoluteFeeScaled);

        // Emit a log with a unique identifier 'n'.
        uint256 receivedAmountUnderlying =
            token.toUnderlying(receivedAmountScaled);
        emit LogMint(msg.sender, receivedAmountUnderlying, nextN, sigHash);
        nextN += 1;

        return receivedAmountScaled;
    }

    /// @notice burn destroys tokens after taking a fee for the `_feeRecipient`,
    ///         allowing the associated assets to be released on their native
    ///         chain.
    ///
    /// @param _to The address to receive the un-bridged asset. The format of
    ///        this address should be of the destination chain.
    ///        For example, when burning to Bitcoin, _to should be a
    ///        Bitcoin address.
    /// @param _amount The amount of the token being burnt, in its
    ///        smallest value. (e.g. satoshis for BTC)
    function burn(bytes memory _to, uint256 _amount) public returns (uint256) {
        // The recipient must not be empty. Better validation is possible,
        // but would need to be customized for each destination ledger.
        require(_to.length != 0, "Gateway: to address is empty");

        // Calculate fee, subtract it from amount being burnt.
        uint256 fee = _amount.mul(burnFee).div(BIPS_DENOMINATOR);
        uint256 amountAfterFee =
            _amount.sub(fee, "Gateway: fee exceeds amount");

        // If the scaled token can represent more precision than the underlying
        // token, the difference is lost. This won't exceed 1 sat, so is
        // negligible compared to burning and transaction fees.
        uint256 amountAfterFeeUnderlying = token.toUnderlying(amountAfterFee);

        // Burn the whole amount, and then re-mint the fee.
        token.burn(msg.sender, _amount);
        token.mint(feeRecipient, fee);

        require(
            // Must be strictly greater, to that the release transaction is of
            // at least one unit.
            amountAfterFeeUnderlying > minimumBurnAmount,
            "Gateway: amount is less than the minimum burn amount"
        );

        emit LogBurn(_to, amountAfterFeeUnderlying, nextN, _to);
        nextN += 1;

        return amountAfterFeeUnderlying;
    }

    /// @notice verifySignature checks the the provided signature matches the
    /// provided parameters.
    function verifySignature(bytes32 _sigHash, bytes memory _sig)
        public
        view
        returns (bool)
    {
        return mintAuthority == ECDSA.recover(_sigHash, _sig);
    }

    /// @notice hashForSignature hashes the parameters so that they can be
    /// signed.
    function hashForSignature(
        bytes32 _pHash,
        uint256 _amount,
        address _to,
        bytes32 _nHash
    ) public view returns (bytes32) {
        return
            keccak256(abi.encode(_pHash, _amount, address(token), _to, _nHash));
    }
}

contract BTCGateway is InitializableAdminUpgradeabilityProxy {}

contract ZECGateway is InitializableAdminUpgradeabilityProxy {}

contract BCHGateway is InitializableAdminUpgradeabilityProxy {}

pragma solidity ^0.5.0;

import './UpgradeabilityProxy.sol';

/**
 * @title BaseAdminUpgradeabilityProxy
 * @dev This contract combines an upgradeability proxy with an authorization
 * mechanism for administrative tasks.
 * All external functions in this contract must be guarded by the
 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
 * feature proposal that would enable this to be done automatically.
 */
contract BaseAdminUpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Emitted when the administration has been transferred.
   * @param previousAdmin Address of the previous admin.
   * @param newAdmin Address of the new admin.
   */
  event AdminChanged(address previousAdmin, address newAdmin);

  /**
   * @dev Storage slot with the admin of the contract.
   * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
   * validated in the constructor.
   */

  bytes32 internal constant ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

  /**
   * @dev Modifier to check whether the `msg.sender` is the admin.
   * If it is, it will run the function. Otherwise, it will delegate the call
   * to the implementation.
   */
  modifier ifAdmin() {
    if (msg.sender == _admin()) {
      _;
    } else {
      _fallback();
    }
  }

  /**
   * @return The address of the proxy admin.
   */
  function admin() external ifAdmin returns (address) {
    return _admin();
  }

  /**
   * @return The address of the implementation.
   */
  function implementation() external ifAdmin returns (address) {
    return _implementation();
  }

  /**
   * @dev Changes the admin of the proxy.
   * Only the current admin can call this function.
   * @param newAdmin Address to transfer proxy administration to.
   */
  function changeAdmin(address newAdmin) external ifAdmin {
    require(newAdmin != address(0), "Cannot change the admin of a proxy to the zero address");
    emit AdminChanged(_admin(), newAdmin);
    _setAdmin(newAdmin);
  }

  /**
   * @dev Upgrade the backing implementation of the proxy.
   * Only the admin can call this function.
   * @param newImplementation Address of the new implementation.
   */
  function upgradeTo(address newImplementation) external ifAdmin {
    _upgradeTo(newImplementation);
  }

  /**
   * @dev Upgrade the backing implementation of the proxy and call a function
   * on the new implementation.
   * This is useful to initialize the proxied contract.
   * @param newImplementation Address of the new implementation.
   * @param data Data to send as msg.data in the low level call.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   */
  function upgradeToAndCall(address newImplementation, bytes calldata data) payable external ifAdmin {
    _upgradeTo(newImplementation);
    (bool success,) = newImplementation.delegatecall(data);
    require(success);
  }

  /**
   * @return The admin slot.
   */
  function _admin() internal view returns (address adm) {
    bytes32 slot = ADMIN_SLOT;
    assembly {
      adm := sload(slot)
    }
  }

  /**
   * @dev Sets the address of the proxy admin.
   * @param newAdmin Address of the new proxy admin.
   */
  function _setAdmin(address newAdmin) internal {
    bytes32 slot = ADMIN_SLOT;

    assembly {
      sstore(slot, newAdmin)
    }
  }

  /**
   * @dev Only fall back when the sender is not the admin.
   */
  function _willFallback() internal {
    require(msg.sender != _admin(), "Cannot call fallback function from the proxy admin");
    super._willFallback();
  }
}

pragma solidity ^0.5.0;

import './BaseUpgradeabilityProxy.sol';

/**
 * @title InitializableUpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with an initializer for initializing
 * implementation and init data.
 */
contract InitializableUpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Contract initializer.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  function initialize(address _logic, bytes memory _data) public payable {
    require(_implementation() == address(0));
    assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
    _setImplementation(_logic);
    if(_data.length > 0) {
      (bool success,) = _logic.delegatecall(_data);
      require(success);
    }
  }  
}

pragma solidity ^0.5.0;

import './BaseUpgradeabilityProxy.sol';

/**
 * @title UpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with a constructor for initializing
 * implementation and init data.
 */
contract UpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Contract constructor.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  constructor(address _logic, bytes memory _data) public payable {
    assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
    _setImplementation(_logic);
    if(_data.length > 0) {
      (bool success,) = _logic.delegatecall(_data);
      require(success);
    }
  }  
}

pragma solidity ^0.5.0;

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

/**
 * @title BaseUpgradeabilityProxy
 * @dev This contract implements a proxy that allows to change the
 * implementation address to which it will delegate.
 * Such a change is called an implementation upgrade.
 */
contract BaseUpgradeabilityProxy is Proxy {
  /**
   * @dev Emitted when the implementation is upgraded.
   * @param implementation Address of the new implementation.
   */
  event Upgraded(address indexed implementation);

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

  /**
   * @dev Returns the current implementation.
   * @return Address of the current implementation
   */
  function _implementation() internal view returns (address impl) {
    bytes32 slot = IMPLEMENTATION_SLOT;
    assembly {
      impl := sload(slot)
    }
  }

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

  /**
   * @dev Sets the implementation address of the proxy.
   * @param newImplementation Address of the new implementation.
   */
  function _setImplementation(address newImplementation) internal {
    require(OpenZeppelinUpgradesAddress.isContract(newImplementation), "Cannot set a proxy implementation to a non-contract address");

    bytes32 slot = IMPLEMENTATION_SLOT;

    assembly {
      sstore(slot, newImplementation)
    }
  }
}

pragma solidity ^0.5.0;

/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
contract Proxy {
  /**
   * @dev Fallback function.
   * Implemented entirely in `_fallback`.
   */
  function () payable external {
    _fallback();
  }

  /**
   * @return The Address of the implementation.
   */
  function _implementation() internal view returns (address);

  /**
   * @dev Delegates execution to an implementation contract.
   * This is a low level function that doesn't return to its internal call site.
   * It will return to the external caller whatever the implementation returns.
   * @param implementation Address to delegate.
   */
  function _delegate(address implementation) internal {
    assembly {
      // Copy msg.data. We take full control of memory in this inline assembly
      // block because it will not return to Solidity code. We overwrite the
      // Solidity scratch pad at memory position 0.
      calldatacopy(0, 0, calldatasize)

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

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

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

  /**
   * @dev Function that is run as the first thing in the fallback function.
   * Can be redefined in derived contracts to add functionality.
   * Redefinitions must call super._willFallback().
   */
  function _willFallback() internal {
  }

  /**
   * @dev fallback implementation.
   * Extracted to enable manual triggering.
   */
  function _fallback() internal {
    _willFallback();
    _delegate(_implementation());
  }
}

pragma solidity ^0.5.0;

/**
 * Utility library of inline functions on addresses
 *
 * Source https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-solidity/v2.1.3/contracts/utils/Address.sol
 * This contract is copied here and renamed from the original to avoid clashes in the compiled artifacts
 * when the user imports a zos-lib contract (that transitively causes this contract to be compiled and added to the
 * build/artifacts folder) as well as the vanilla Address implementation from an openzeppelin version.
 */
library OpenZeppelinUpgradesAddress {
    /**
     * Returns whether the target address is a contract
     * @dev This function will return false if invoked during the constructor of a contract,
     * as the code is not actually created until after the constructor finishes.
     * @param account address of the account to check
     * @return whether the target address is a contract
     */
    function isContract(address account) internal view returns (bool) {
        uint256 size;
        // XXX Currently there is no better way to check if there is a contract in an address
        // than to check the size of the code at that address.
        // See https://ethereum.stackexchange.com/a/14016/36603
        // for more details about how this works.
        // TODO Check this again before the Serenity release, because all addresses will be
        // contracts then.
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";

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.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be aplied to your functions to restrict their use to
 * the owner.
 */
contract Ownable is Initializable, Context {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function initialize(address sender) public initializer {
        _owner = sender;
        emit OwnershipTransferred(address(0), _owner);
    }

    /**
     * @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(isOwner(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Returns true if the caller is the current owner.
     */
    function isOwner() public view returns (bool) {
        return _msgSender() == _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 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 onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }

    uint256[50] private ______gap;
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
contract Context is Initializable {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

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

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

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";

import "../../GSN/Context.sol";
import "./IERC20.sol";
import "../../math/SafeMath.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 {ERC20Mintable}.
 *
 * 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 Initializable, Context, IERC20 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

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

    uint256 private _totalSupply;

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

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

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

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public 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 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 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 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 {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

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

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

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

        _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 {
        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 Destroys `amount` tokens from `account`.`amount` is then deducted
     * from the caller's allowance.
     *
     * See {_burn} and {_approve}.
     */
    function _burnFrom(address account, uint256 amount) internal {
        _burn(account, amount);
        _approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
    }

    uint256[50] private ______gap;
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "./IERC20.sol";

/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is Initializable, IERC20 {
    string private _name;
    string internal _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
     * these values are immutable: they can only be set once during
     * construction.
     */
    function initialize(string memory name, string memory symbol, uint8 decimals) public initializer {
        _name = name;
        _symbol = symbol;
        _decimals = decimals;
    }

    /**
     * @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.
     *
     * 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;
    }

    uint256[50] private ______gap;
}

pragma solidity ^0.5.17;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";

import "../Governance/Claimable.sol";

/// @notice ERC20WithRate allows for a more dynamic fee model by storing a rate
/// that tracks the number of the underlying asset's unit represented by a
/// single ERC20 token.
contract ERC20WithRate is Initializable, Ownable, ERC20 {
    using SafeMath for uint256;

    uint256 public constant _rateScale = 1e18;
    uint256 internal _rate;

    event LogRateChanged(uint256 indexed _rate);

    /* solium-disable-next-line no-empty-blocks */
    function initialize(address _nextOwner, uint256 _initialRate)
        public
        initializer
    {
        Ownable.initialize(_nextOwner);
        _setRate(_initialRate);
    }

    function setExchangeRate(uint256 _nextRate) public onlyOwner {
        _setRate(_nextRate);
    }

    function exchangeRateCurrent() public view returns (uint256) {
        require(_rate != 0, "ERC20WithRate: rate has not been initialized");
        return _rate;
    }

    function _setRate(uint256 _nextRate) internal {
        require(_nextRate > 0, "ERC20WithRate: rate must be greater than zero");
        _rate = _nextRate;
    }

    function balanceOfUnderlying(address _account)
        public
        view
        returns (uint256)
    {
        return toUnderlying(balanceOf(_account));
    }

    function toUnderlying(uint256 _amount) public view returns (uint256) {
        return _amount.mul(_rate).div(_rateScale);
    }

    function fromUnderlying(uint256 _amountUnderlying)
        public
        view
        returns (uint256)
    {
        return _amountUnderlying.mul(_rateScale).div(_rate);
    }
}

pragma solidity ^0.5.17;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/ERC20Detailed.sol";

/// @notice Taken from the DAI token.
contract ERC20WithPermit is Initializable, ERC20, ERC20Detailed {
    using SafeMath for uint256;

    mapping(address => uint256) public nonces;

    // If the token is redeployed, the version is increased to prevent a permit
    // signature being used on both token instances.
    string public version;

    // --- EIP712 niceties ---
    bytes32 public DOMAIN_SEPARATOR;
    // PERMIT_TYPEHASH is the value returned from
    // keccak256("Permit(address holder,address spender,uint256 nonce,uint256 expiry,bool allowed)")
    bytes32 public constant PERMIT_TYPEHASH =
        0xea2aa0a1be11a07ed86d755c93467f4f82362b452371d1ba94d1715123511acb;

    function initialize(
        uint256 _chainId,
        string memory _version,
        string memory _name,
        string memory _symbol,
        uint8 _decimals
    ) public initializer {
        ERC20Detailed.initialize(_name, _symbol, _decimals);
        version = _version;
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256(
                    "EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"
                ),
                keccak256(bytes(name())),
                keccak256(bytes(version)),
                _chainId,
                address(this)
            )
        );
    }

    // --- Approve by signature ---
    function permit(
        address holder,
        address spender,
        uint256 nonce,
        uint256 expiry,
        bool allowed,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external {
        bytes32 digest =
            keccak256(
                abi.encodePacked(
                    "\x19\x01",
                    DOMAIN_SEPARATOR,
                    keccak256(
                        abi.encode(
                            PERMIT_TYPEHASH,
                            holder,
                            spender,
                            nonce,
                            expiry,
                            allowed
                        )
                    )
                )
            );

        require(holder != address(0), "ERC20WithRate: address must not be 0x0");
        require(
            holder == ecrecover(digest, v, r, s),
            "ERC20WithRate: invalid signature"
        );
        require(
            expiry == 0 || now <= expiry,
            "ERC20WithRate: permit has expired"
        );
        require(nonce == nonces[holder]++, "ERC20WithRate: invalid nonce");
        uint256 amount = allowed ? uint256(-1) : 0;
        _approve(holder, spender, amount);
    }
}

pragma solidity ^0.5.0;

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

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

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

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

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

pragma solidity ^0.5.0;

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");
        }
    }
}

pragma solidity ^0.5.5;

/**
 * @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 Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }

    /**
     * @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].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

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

pragma solidity ^0.5.17;

/**
 * @notice LinkedList is a library for a circular double linked list.
 */
library LinkedList {
    /*
     * @notice A permanent NULL node (0x0) in the circular double linked list.
     * NULL.next is the head, and NULL.previous is the tail.
     */
    address public constant NULL = address(0);

    /**
     * @notice A node points to the node before it, and the node after it. If
     * node.previous = NULL, then the node is the head of the list. If
     * node.next = NULL, then the node is the tail of the list.
     */
    struct Node {
        bool inList;
        address previous;
        address next;
    }

    /**
     * @notice LinkedList uses a mapping from address to nodes. Each address
     * uniquely identifies a node, and in this way they are used like pointers.
     */
    struct List {
        mapping(address => Node) list;
    }

    /**
     * @notice Insert a new node before an existing node.
     *
     * @param self The list being used.
     * @param target The existing node in the list.
     * @param newNode The next node to insert before the target.
     */
    function insertBefore(
        List storage self,
        address target,
        address newNode
    ) internal {
        require(newNode != address(0), "LinkedList: invalid address");
        require(!isInList(self, newNode), "LinkedList: already in list");
        require(
            isInList(self, target) || target == NULL,
            "LinkedList: not in list"
        );

        // It is expected that this value is sometimes NULL.
        address prev = self.list[target].previous;

        self.list[newNode].next = target;
        self.list[newNode].previous = prev;
        self.list[target].previous = newNode;
        self.list[prev].next = newNode;

        self.list[newNode].inList = true;
    }

    /**
     * @notice Insert a new node after an existing node.
     *
     * @param self The list being used.
     * @param target The existing node in the list.
     * @param newNode The next node to insert after the target.
     */
    function insertAfter(
        List storage self,
        address target,
        address newNode
    ) internal {
        require(newNode != address(0), "LinkedList: invalid address");
        require(!isInList(self, newNode), "LinkedList: already in list");
        require(
            isInList(self, target) || target == NULL,
            "LinkedList: not in list"
        );

        // It is expected that this value is sometimes NULL.
        address n = self.list[target].next;

        self.list[newNode].previous = target;
        self.list[newNode].next = n;
        self.list[target].next = newNode;
        self.list[n].previous = newNode;

        self.list[newNode].inList = true;
    }

    /**
     * @notice Remove a node from the list, and fix the previous and next
     * pointers that are pointing to the removed node. Removing anode that is not
     * in the list will do nothing.
     *
     * @param self The list being using.
     * @param node The node in the list to be removed.
     */
    function remove(List storage self, address node) internal {
        require(isInList(self, node), "LinkedList: not in list");

        address p = self.list[node].previous;
        address n = self.list[node].next;

        self.list[p].next = n;
        self.list[n].previous = p;

        // Deleting the node should set this value to false, but we set it here for
        // explicitness.
        self.list[node].inList = false;
        delete self.list[node];
    }

    /**
     * @notice Insert a node at the beginning of the list.
     *
     * @param self The list being used.
     * @param node The node to insert at the beginning of the list.
     */
    function prepend(List storage self, address node) internal {
        // isInList(node) is checked in insertBefore

        insertBefore(self, begin(self), node);
    }

    /**
     * @notice Insert a node at the end of the list.
     *
     * @param self The list being used.
     * @param node The node to insert at the end of the list.
     */
    function append(List storage self, address node) internal {
        // isInList(node) is checked in insertBefore

        insertAfter(self, end(self), node);
    }

    function swap(
        List storage self,
        address left,
        address right
    ) internal {
        // isInList(left) and isInList(right) are checked in remove

        address previousRight = self.list[right].previous;
        remove(self, right);
        insertAfter(self, left, right);
        remove(self, left);
        insertAfter(self, previousRight, left);
    }

    function isInList(List storage self, address node)
        internal
        view
        returns (bool)
    {
        return self.list[node].inList;
    }

    /**
     * @notice Get the node at the beginning of a double linked list.
     *
     * @param self The list being used.
     *
     * @return A address identifying the node at the beginning of the double
     * linked list.
     */
    function begin(List storage self) internal view returns (address) {
        return self.list[NULL].next;
    }

    /**
     * @notice Get the node at the end of a double linked list.
     *
     * @param self The list being used.
     *
     * @return A address identifying the node at the end of the double linked
     * list.
     */
    function end(List storage self) internal view returns (address) {
        return self.list[NULL].previous;
    }

    function next(List storage self, address node)
        internal
        view
        returns (address)
    {
        require(isInList(self, node), "LinkedList: not in list");
        return self.list[node].next;
    }

    function previous(List storage self, address node)
        internal
        view
        returns (address)
    {
        require(isInList(self, node), "LinkedList: not in list");
        return self.list[node].previous;
    }

    function elements(
        List storage self,
        address _start,
        uint256 _count
    ) internal view returns (address[] memory) {
        require(_count > 0, "LinkedList: invalid count");
        require(
            isInList(self, _start) || _start == address(0),
            "LinkedList: not in list"
        );
        address[] memory elems = new address[](_count);

        // Begin with the first node in the list
        uint256 n = 0;
        address nextItem = _start;
        if (nextItem == address(0)) {
            nextItem = begin(self);
        }

        while (n < _count) {
            if (nextItem == address(0)) {
                break;
            }
            elems[n] = nextItem;
            nextItem = next(self, nextItem);
            n += 1;
        }
        return elems;
    }
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "./ERC20.sol";
import "../../access/roles/MinterRole.sol";

/**
 * @dev Extension of {ERC20} that adds a set of accounts with the {MinterRole},
 * which have permission to mint (create) new tokens as they see fit.
 *
 * At construction, the deployer of the contract is the only minter.
 */
contract ERC20Mintable is Initializable, ERC20, MinterRole {
    function initialize(address sender) public initializer {
        MinterRole.initialize(sender);
    }

    /**
     * @dev See {ERC20-_mint}.
     *
     * Requirements:
     *
     * - the caller must have the {MinterRole}.
     */
    function mint(address account, uint256 amount) public onlyMinter returns (bool) {
        _mint(account, amount);
        return true;
    }

    uint256[50] private ______gap;
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "./ERC20.sol";
import "../../lifecycle/Pausable.sol";

/**
 * @title Pausable token
 * @dev ERC20 with pausable transfers and allowances.
 *
 * Useful if you want to stop trades until the end of a crowdsale, or have
 * an emergency switch for freezing all token transfers in the event of a large
 * bug.
 */
contract ERC20Pausable is Initializable, ERC20, Pausable {
    function initialize(address sender) public initializer {
        Pausable.initialize(sender);
    }

    function transfer(address to, uint256 value) public whenNotPaused returns (bool) {
        return super.transfer(to, value);
    }

    function transferFrom(address from, address to, uint256 value) public whenNotPaused returns (bool) {
        return super.transferFrom(from, to, value);
    }

    function approve(address spender, uint256 value) public whenNotPaused returns (bool) {
        return super.approve(spender, value);
    }

    function increaseAllowance(address spender, uint256 addedValue) public whenNotPaused returns (bool) {
        return super.increaseAllowance(spender, addedValue);
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public whenNotPaused returns (bool) {
        return super.decreaseAllowance(spender, subtractedValue);
    }

    uint256[50] private ______gap;
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";

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

contract MinterRole is Initializable, Context {
    using Roles for Roles.Role;

    event MinterAdded(address indexed account);
    event MinterRemoved(address indexed account);

    Roles.Role private _minters;

    function initialize(address sender) public initializer {
        if (!isMinter(sender)) {
            _addMinter(sender);
        }
    }

    modifier onlyMinter() {
        require(isMinter(_msgSender()), "MinterRole: caller does not have the Minter role");
        _;
    }

    function isMinter(address account) public view returns (bool) {
        return _minters.has(account);
    }

    function addMinter(address account) public onlyMinter {
        _addMinter(account);
    }

    function renounceMinter() public {
        _removeMinter(_msgSender());
    }

    function _addMinter(address account) internal {
        _minters.add(account);
        emit MinterAdded(account);
    }

    function _removeMinter(address account) internal {
        _minters.remove(account);
        emit MinterRemoved(account);
    }

    uint256[50] private ______gap;
}

pragma solidity ^0.5.0;

/**
 * @title Roles
 * @dev Library for managing addresses assigned to a Role.
 */
library Roles {
    struct Role {
        mapping (address => bool) bearer;
    }

    /**
     * @dev Give an account access to this role.
     */
    function add(Role storage role, address account) internal {
        require(!has(role, account), "Roles: account already has role");
        role.bearer[account] = true;
    }

    /**
     * @dev Remove an account's access to this role.
     */
    function remove(Role storage role, address account) internal {
        require(has(role, account), "Roles: account does not have role");
        role.bearer[account] = false;
    }

    /**
     * @dev Check if an account has this role.
     * @return bool
     */
    function has(Role storage role, address account) internal view returns (bool) {
        require(account != address(0), "Roles: account is the zero address");
        return role.bearer[account];
    }
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";

import "../GSN/Context.sol";
import "../access/roles/PauserRole.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 Initializable, Context, PauserRole {
    /**
     * @dev Emitted when the pause is triggered by a pauser (`account`).
     */
    event Paused(address account);

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

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state. Assigns the Pauser role
     * to the deployer.
     */
    function initialize(address sender) public initializer {
        PauserRole.initialize(sender);

        _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 Called by a pauser to pause, triggers stopped state.
     */
    function pause() public onlyPauser whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Called by a pauser to unpause, returns to normal state.
     */
    function unpause() public onlyPauser whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }

    uint256[50] private ______gap;
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";

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

contract PauserRole is Initializable, Context {
    using Roles for Roles.Role;

    event PauserAdded(address indexed account);
    event PauserRemoved(address indexed account);

    Roles.Role private _pausers;

    function initialize(address sender) public initializer {
        if (!isPauser(sender)) {
            _addPauser(sender);
        }
    }

    modifier onlyPauser() {
        require(isPauser(_msgSender()), "PauserRole: caller does not have the Pauser role");
        _;
    }

    function isPauser(address account) public view returns (bool) {
        return _pausers.has(account);
    }

    function addPauser(address account) public onlyPauser {
        _addPauser(account);
    }

    function renouncePauser() public {
        _removePauser(_msgSender());
    }

    function _addPauser(address account) internal {
        _pausers.add(account);
        emit PauserAdded(account);
    }

    function _removePauser(address account) internal {
        _pausers.remove(account);
        emit PauserRemoved(account);
    }

    uint256[50] private ______gap;
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";

import "./IRelayRecipient.sol";
import "./IRelayHub.sol";
import "./Context.sol";

/**
 * @dev Base GSN recipient contract: includes the {IRelayRecipient} interface
 * and enables GSN support on all contracts in the inheritance tree.
 *
 * TIP: This contract is abstract. The functions {IRelayRecipient-acceptRelayedCall},
 *  {_preRelayedCall}, and {_postRelayedCall} are not implemented and must be
 * provided by derived contracts. See the
 * xref:ROOT:gsn-strategies.adoc#gsn-strategies[GSN strategies] for more
 * information on how to use the pre-built {GSNRecipientSignature} and
 * {GSNRecipientERC20Fee}, or how to write your own.
 */
contract GSNRecipient is Initializable, IRelayRecipient, Context {
    function initialize() public initializer {
        if (_relayHub == address(0)) {
            setDefaultRelayHub();
        }
    }

    function setDefaultRelayHub() public {
        _upgradeRelayHub(0xD216153c06E857cD7f72665E0aF1d7D82172F494);
    }

    // Default RelayHub address, deployed on mainnet and all testnets at the same address
    address private _relayHub;

    uint256 constant private RELAYED_CALL_ACCEPTED = 0;
    uint256 constant private RELAYED_CALL_REJECTED = 11;

    // How much gas is forwarded to postRelayedCall
    uint256 constant internal POST_RELAYED_CALL_MAX_GAS = 100000;

    /**
     * @dev Emitted when a contract changes its {IRelayHub} contract to a new one.
     */
    event RelayHubChanged(address indexed oldRelayHub, address indexed newRelayHub);

    /**
     * @dev Returns the address of the {IRelayHub} contract for this recipient.
     */
    function getHubAddr() public view returns (address) {
        return _relayHub;
    }

    /**
     * @dev Switches to a new {IRelayHub} instance. This method is added for future-proofing: there's no reason to not
     * use the default instance.
     *
     * IMPORTANT: After upgrading, the {GSNRecipient} will no longer be able to receive relayed calls from the old
     * {IRelayHub} instance. Additionally, all funds should be previously withdrawn via {_withdrawDeposits}.
     */
    function _upgradeRelayHub(address newRelayHub) internal {
        address currentRelayHub = _relayHub;
        require(newRelayHub != address(0), "GSNRecipient: new RelayHub is the zero address");
        require(newRelayHub != currentRelayHub, "GSNRecipient: new RelayHub is the current one");

        emit RelayHubChanged(currentRelayHub, newRelayHub);

        _relayHub = newRelayHub;
    }

    /**
     * @dev Returns the version string of the {IRelayHub} for which this recipient implementation was built. If
     * {_upgradeRelayHub} is used, the new {IRelayHub} instance should be compatible with this version.
     */
    // This function is view for future-proofing, it may require reading from
    // storage in the future.
    function relayHubVersion() public view returns (string memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return "1.0.0";
    }

    /**
     * @dev Withdraws the recipient's deposits in `RelayHub`.
     *
     * Derived contracts should expose this in an external interface with proper access control.
     */
    function _withdrawDeposits(uint256 amount, address payable payee) internal {
        IRelayHub(_relayHub).withdraw(amount, payee);
    }

    // Overrides for Context's functions: when called from RelayHub, sender and
    // data require some pre-processing: the actual sender is stored at the end
    // of the call data, which in turns means it needs to be removed from it
    // when handling said data.

    /**
     * @dev Replacement for msg.sender. Returns the actual sender of a transaction: msg.sender for regular transactions,
     * and the end-user for GSN relayed calls (where msg.sender is actually `RelayHub`).
     *
     * IMPORTANT: Contracts derived from {GSNRecipient} should never use `msg.sender`, and use {_msgSender} instead.
     */
    function _msgSender() internal view returns (address payable) {
        if (msg.sender != _relayHub) {
            return msg.sender;
        } else {
            return _getRelayedCallSender();
        }
    }

    /**
     * @dev Replacement for msg.data. Returns the actual calldata of a transaction: msg.data for regular transactions,
     * and a reduced version for GSN relayed calls (where msg.data contains additional information).
     *
     * IMPORTANT: Contracts derived from {GSNRecipient} should never use `msg.data`, and use {_msgData} instead.
     */
    function _msgData() internal view returns (bytes memory) {
        if (msg.sender != _relayHub) {
            return msg.data;
        } else {
            return _getRelayedCallData();
        }
    }

    // Base implementations for pre and post relayedCall: only RelayHub can invoke them, and data is forwarded to the
    // internal hook.

    /**
     * @dev See `IRelayRecipient.preRelayedCall`.
     *
     * This function should not be overriden directly, use `_preRelayedCall` instead.
     *
     * * Requirements:
     *
     * - the caller must be the `RelayHub` contract.
     */
    function preRelayedCall(bytes calldata context) external returns (bytes32) {
        require(msg.sender == getHubAddr(), "GSNRecipient: caller is not RelayHub");
        return _preRelayedCall(context);
    }

    /**
     * @dev See `IRelayRecipient.preRelayedCall`.
     *
     * Called by `GSNRecipient.preRelayedCall`, which asserts the caller is the `RelayHub` contract. Derived contracts
     * must implement this function with any relayed-call preprocessing they may wish to do.
     *
     */
    function _preRelayedCall(bytes memory context) internal returns (bytes32);

    /**
     * @dev See `IRelayRecipient.postRelayedCall`.
     *
     * This function should not be overriden directly, use `_postRelayedCall` instead.
     *
     * * Requirements:
     *
     * - the caller must be the `RelayHub` contract.
     */
    function postRelayedCall(bytes calldata context, bool success, uint256 actualCharge, bytes32 preRetVal) external {
        require(msg.sender == getHubAddr(), "GSNRecipient: caller is not RelayHub");
        _postRelayedCall(context, success, actualCharge, preRetVal);
    }

    /**
     * @dev See `IRelayRecipient.postRelayedCall`.
     *
     * Called by `GSNRecipient.postRelayedCall`, which asserts the caller is the `RelayHub` contract. Derived contracts
     * must implement this function with any relayed-call postprocessing they may wish to do.
     *
     */
    function _postRelayedCall(bytes memory context, bool success, uint256 actualCharge, bytes32 preRetVal) internal;

    /**
     * @dev Return this in acceptRelayedCall to proceed with the execution of a relayed call. Note that this contract
     * will be charged a fee by RelayHub
     */
    function _approveRelayedCall() internal pure returns (uint256, bytes memory) {
        return _approveRelayedCall("");
    }

    /**
     * @dev See `GSNRecipient._approveRelayedCall`.
     *
     * This overload forwards `context` to _preRelayedCall and _postRelayedCall.
     */
    function _approveRelayedCall(bytes memory context) internal pure returns (uint256, bytes memory) {
        return (RELAYED_CALL_ACCEPTED, context);
    }

    /**
     * @dev Return this in acceptRelayedCall to impede execution of a relayed call. No fees will be charged.
     */
    function _rejectRelayedCall(uint256 errorCode) internal pure returns (uint256, bytes memory) {
        return (RELAYED_CALL_REJECTED + errorCode, "");
    }

    /*
     * @dev Calculates how much RelayHub will charge a recipient for using `gas` at a `gasPrice`, given a relayer's
     * `serviceFee`.
     */
    function _computeCharge(uint256 gas, uint256 gasPrice, uint256 serviceFee) internal pure returns (uint256) {
        // The fee is expressed as a percentage. E.g. a value of 40 stands for a 40% fee, so the recipient will be
        // charged for 1.4 times the spent amount.
        return (gas * gasPrice * (100 + serviceFee)) / 100;
    }

    function _getRelayedCallSender() private pure returns (address payable result) {
        // We need to read 20 bytes (an address) located at array index msg.data.length - 20. In memory, the array
        // is prefixed with a 32-byte length value, so we first add 32 to get the memory read index. However, doing
        // so would leave the address in the upper 20 bytes of the 32-byte word, which is inconvenient and would
        // require bit shifting. We therefore subtract 12 from the read index so the address lands on the lower 20
        // bytes. This can always be done due to the 32-byte prefix.

        // The final memory read index is msg.data.length - 20 + 32 - 12 = msg.data.length. Using inline assembly is the
        // easiest/most-efficient way to perform this operation.

        // These fields are not accessible from assembly
        bytes memory array = msg.data;
        uint256 index = msg.data.length;

        // solhint-disable-next-line no-inline-assembly
        assembly {
            // Load the 32 bytes word from memory with the address on the lower 20 bytes, and mask those.
            result := and(mload(add(array, index)), 0xffffffffffffffffffffffffffffffffffffffff)
        }
        return result;
    }

    function _getRelayedCallData() private pure returns (bytes memory) {
        // RelayHub appends the sender address at the end of the calldata, so in order to retrieve the actual msg.data,
        // we must strip the last 20 bytes (length of an address type) from it.

        uint256 actualDataLength = msg.data.length - 20;
        bytes memory actualData = new bytes(actualDataLength);

        for (uint256 i = 0; i < actualDataLength; ++i) {
            actualData[i] = msg.data[i];
        }

        return actualData;
    }
}

pragma solidity ^0.5.0;

/**
 * @dev Base interface for a contract that will be called via the GSN from {IRelayHub}.
 *
 * TIP: You don't need to write an implementation yourself! Inherit from {GSNRecipient} instead.
 */
interface IRelayRecipient {
    /**
     * @dev Returns the address of the {IRelayHub} instance this recipient interacts with.
     */
    function getHubAddr() external view returns (address);

    /**
     * @dev Called by {IRelayHub} to validate if this recipient accepts being charged for a relayed call. Note that the
     * recipient will be charged regardless of the execution result of the relayed call (i.e. if it reverts or not).
     *
     * The relay request was originated by `from` and will be served by `relay`. `encodedFunction` is the relayed call
     * calldata, so its first four bytes are the function selector. The relayed call will be forwarded `gasLimit` gas,
     * and the transaction executed with a gas price of at least `gasPrice`. `relay`'s fee is `transactionFee`, and the
     * recipient will be charged at most `maxPossibleCharge` (in wei). `nonce` is the sender's (`from`) nonce for
     * replay attack protection in {IRelayHub}, and `approvalData` is a optional parameter that can be used to hold a signature
     * over all or some of the previous values.
     *
     * Returns a tuple, where the first value is used to indicate approval (0) or rejection (custom non-zero error code,
     * values 1 to 10 are reserved) and the second one is data to be passed to the other {IRelayRecipient} functions.
     *
     * {acceptRelayedCall} is called with 50k gas: if it runs out during execution, the request will be considered
     * rejected. A regular revert will also trigger a rejection.
     */
    function acceptRelayedCall(
        address relay,
        address from,
        bytes calldata encodedFunction,
        uint256 transactionFee,
        uint256 gasPrice,
        uint256 gasLimit,
        uint256 nonce,
        bytes calldata approvalData,
        uint256 maxPossibleCharge
    )
        external
        view
        returns (uint256, bytes memory);

    /**
     * @dev Called by {IRelayHub} on approved relay call requests, before the relayed call is executed. This allows to e.g.
     * pre-charge the sender of the transaction.
     *
     * `context` is the second value returned in the tuple by {acceptRelayedCall}.
     *
     * Returns a value to be passed to {postRelayedCall}.
     *
     * {preRelayedCall} is called with 100k gas: if it runs out during exection or otherwise reverts, the relayed call
     * will not be executed, but the recipient will still be charged for the transaction's cost.
     */
    function preRelayedCall(bytes calldata context) external returns (bytes32);

    /**
     * @dev Called by {IRelayHub} on approved relay call requests, after the relayed call is executed. This allows to e.g.
     * charge the user for the relayed call costs, return any overcharges from {preRelayedCall}, or perform
     * contract-specific bookkeeping.
     *
     * `context` is the second value returned in the tuple by {acceptRelayedCall}. `success` is the execution status of
     * the relayed call. `actualCharge` is an estimate of how much the recipient will be charged for the transaction,
     * not including any gas used by {postRelayedCall} itself. `preRetVal` is {preRelayedCall}'s return value.
     *
     *
     * {postRelayedCall} is called with 100k gas: if it runs out during execution or otherwise reverts, the relayed call
     * and the call to {preRelayedCall} will be reverted retroactively, but the recipient will still be charged for the
     * transaction's cost.
     */
    function postRelayedCall(bytes calldata context, bool success, uint256 actualCharge, bytes32 preRetVal) external;
}

pragma solidity ^0.5.0;

/**
 * @dev Interface for `RelayHub`, the core contract of the GSN. Users should not need to interact with this contract
 * directly.
 *
 * See the https://github.com/OpenZeppelin/openzeppelin-gsn-helpers[OpenZeppelin GSN helpers] for more information on
 * how to deploy an instance of `RelayHub` on your local test network.
 */
interface IRelayHub {
    // Relay management

    /**
     * @dev Adds stake to a relay and sets its `unstakeDelay`. If the relay does not exist, it is created, and the caller
     * of this function becomes its owner. If the relay already exists, only the owner can call this function. A relay
     * cannot be its own owner.
     *
     * All Ether in this function call will be added to the relay's stake.
     * Its unstake delay will be assigned to `unstakeDelay`, but the new value must be greater or equal to the current one.
     *
     * Emits a {Staked} event.
     */
    function stake(address relayaddr, uint256 unstakeDelay) external payable;

    /**
     * @dev Emitted when a relay's stake or unstakeDelay are increased
     */
    event Staked(address indexed relay, uint256 stake, uint256 unstakeDelay);

    /**
     * @dev Registers the caller as a relay.
     * The relay must be staked for, and not be a contract (i.e. this function must be called directly from an EOA).
     *
     * This function can be called multiple times, emitting new {RelayAdded} events. Note that the received
     * `transactionFee` is not enforced by {relayCall}.
     *
     * Emits a {RelayAdded} event.
     */
    function registerRelay(uint256 transactionFee, string calldata url) external;

    /**
     * @dev Emitted when a relay is registered or re-registerd. Looking at these events (and filtering out
     * {RelayRemoved} events) lets a client discover the list of available relays.
     */
    event RelayAdded(address indexed relay, address indexed owner, uint256 transactionFee, uint256 stake, uint256 unstakeDelay, string url);

    /**
     * @dev Removes (deregisters) a relay. Unregistered (but staked for) relays can also be removed.
     *
     * Can only be called by the owner of the relay. After the relay's `unstakeDelay` has elapsed, {unstake} will be
     * callable.
     *
     * Emits a {RelayRemoved} event.
     */
    function removeRelayByOwner(address relay) external;

    /**
     * @dev Emitted when a relay is removed (deregistered). `unstakeTime` is the time when unstake will be callable.
     */
    event RelayRemoved(address indexed relay, uint256 unstakeTime);

    /** Deletes the relay from the system, and gives back its stake to the owner.
     *
     * Can only be called by the relay owner, after `unstakeDelay` has elapsed since {removeRelayByOwner} was called.
     *
     * Emits an {Unstaked} event.
     */
    function unstake(address relay) external;

    /**
     * @dev Emitted when a relay is unstaked for, including the returned stake.
     */
    event Unstaked(address indexed relay, uint256 stake);

    // States a relay can be in
    enum RelayState {
        Unknown, // The relay is unknown to the system: it has never been staked for
        Staked, // The relay has been staked for, but it is not yet active
        Registered, // The relay has registered itself, and is active (can relay calls)
        Removed    // The relay has been removed by its owner and can no longer relay calls. It must wait for its unstakeDelay to elapse before it can unstake
    }

    /**
     * @dev Returns a relay's status. Note that relays can be deleted when unstaked or penalized, causing this function
     * to return an empty entry.
     */
    function getRelay(address relay) external view returns (uint256 totalStake, uint256 unstakeDelay, uint256 unstakeTime, address payable owner, RelayState state);

    // Balance management

    /**
     * @dev Deposits Ether for a contract, so that it can receive (and pay for) relayed transactions.
     *
     * Unused balance can only be withdrawn by the contract itself, by calling {withdraw}.
     *
     * Emits a {Deposited} event.
     */
    function depositFor(address target) external payable;

    /**
     * @dev Emitted when {depositFor} is called, including the amount and account that was funded.
     */
    event Deposited(address indexed recipient, address indexed from, uint256 amount);

    /**
     * @dev Returns an account's deposits. These can be either a contracts's funds, or a relay owner's revenue.
     */
    function balanceOf(address target) external view returns (uint256);

    /**
     * Withdraws from an account's balance, sending it back to it. Relay owners call this to retrieve their revenue, and
     * contracts can use it to reduce their funding.
     *
     * Emits a {Withdrawn} event.
     */
    function withdraw(uint256 amount, address payable dest) external;

    /**
     * @dev Emitted when an account withdraws funds from `RelayHub`.
     */
    event Withdrawn(address indexed account, address indexed dest, uint256 amount);

    // Relaying

    /**
     * @dev Checks if the `RelayHub` will accept a relayed operation.
     * Multiple things must be true for this to happen:
     *  - all arguments must be signed for by the sender (`from`)
     *  - the sender's nonce must be the current one
     *  - the recipient must accept this transaction (via {acceptRelayedCall})
     *
     * Returns a `PreconditionCheck` value (`OK` when the transaction can be relayed), or a recipient-specific error
     * code if it returns one in {acceptRelayedCall}.
     */
    function canRelay(
        address relay,
        address from,
        address to,
        bytes calldata encodedFunction,
        uint256 transactionFee,
        uint256 gasPrice,
        uint256 gasLimit,
        uint256 nonce,
        bytes calldata signature,
        bytes calldata approvalData
    ) external view returns (uint256 status, bytes memory recipientContext);

    // Preconditions for relaying, checked by canRelay and returned as the corresponding numeric values.
    enum PreconditionCheck {
        OK,                         // All checks passed, the call can be relayed
        WrongSignature,             // The transaction to relay is not signed by requested sender
        WrongNonce,                 // The provided nonce has already been used by the sender
        AcceptRelayedCallReverted,  // The recipient rejected this call via acceptRelayedCall
        InvalidRecipientStatusCode  // The recipient returned an invalid (reserved) status code
    }

    /**
     * @dev Relays a transaction.
     *
     * For this to succeed, multiple conditions must be met:
     *  - {canRelay} must `return PreconditionCheck.OK`
     *  - the sender must be a registered relay
     *  - the transaction's gas price must be larger or equal to the one that was requested by the sender
     *  - the transaction must have enough gas to not run out of gas if all internal transactions (calls to the
     * recipient) use all gas available to them
     *  - the recipient must have enough balance to pay the relay for the worst-case scenario (i.e. when all gas is
     * spent)
     *
     * If all conditions are met, the call will be relayed and the recipient charged. {preRelayedCall}, the encoded
     * function and {postRelayedCall} will be called in that order.
     *
     * Parameters:
     *  - `from`: the client originating the request
     *  - `to`: the target {IRelayRecipient} contract
     *  - `encodedFunction`: the function call to relay, including data
     *  - `transactionFee`: fee (%) the relay takes over actual gas cost
     *  - `gasPrice`: gas price the client is willing to pay
     *  - `gasLimit`: gas to forward when calling the encoded function
     *  - `nonce`: client's nonce
     *  - `signature`: client's signature over all previous params, plus the relay and RelayHub addresses
     *  - `approvalData`: dapp-specific data forwared to {acceptRelayedCall}. This value is *not* verified by the
     * `RelayHub`, but it still can be used for e.g. a signature.
     *
     * Emits a {TransactionRelayed} event.
     */
    function relayCall(
        address from,
        address to,
        bytes calldata encodedFunction,
        uint256 transactionFee,
        uint256 gasPrice,
        uint256 gasLimit,
        uint256 nonce,
        bytes calldata signature,
        bytes calldata approvalData
    ) external;

    /**
     * @dev Emitted when an attempt to relay a call failed.
     *
     * This can happen due to incorrect {relayCall} arguments, or the recipient not accepting the relayed call. The
     * actual relayed call was not executed, and the recipient not charged.
     *
     * The `reason` parameter contains an error code: values 1-10 correspond to `PreconditionCheck` entries, and values
     * over 10 are custom recipient error codes returned from {acceptRelayedCall}.
     */
    event CanRelayFailed(address indexed relay, address indexed from, address indexed to, bytes4 selector, uint256 reason);

    /**
     * @dev Emitted when a transaction is relayed. 
     * Useful when monitoring a relay's operation and relayed calls to a contract
     *
     * Note that the actual encoded function might be reverted: this is indicated in the `status` parameter.
     *
     * `charge` is the Ether value deducted from the recipient's balance, paid to the relay's owner.
     */
    event TransactionRelayed(address indexed relay, address indexed from, address indexed to, bytes4 selector, RelayCallStatus status, uint256 charge);

    // Reason error codes for the TransactionRelayed event
    enum RelayCallStatus {
        OK,                      // The transaction was successfully relayed and execution successful - never included in the event
        RelayedCallFailed,       // The transaction was relayed, but the relayed call failed
        PreRelayedFailed,        // The transaction was not relayed due to preRelatedCall reverting
        PostRelayedFailed,       // The transaction was relayed and reverted due to postRelatedCall reverting
        RecipientBalanceChanged  // The transaction was relayed and reverted due to the recipient's balance changing
    }

    /**
     * @dev Returns how much gas should be forwarded to a call to {relayCall}, in order to relay a transaction that will
     * spend up to `relayedCallStipend` gas.
     */
    function requiredGas(uint256 relayedCallStipend) external view returns (uint256);

    /**
     * @dev Returns the maximum recipient charge, given the amount of gas forwarded, gas price and relay fee.
     */
    function maxPossibleCharge(uint256 relayedCallStipend, uint256 gasPrice, uint256 transactionFee) external view returns (uint256);

     // Relay penalization. 
     // Any account can penalize relays, removing them from the system immediately, and rewarding the
    // reporter with half of the relay's stake. The other half is burned so that, even if the relay penalizes itself, it
    // still loses half of its stake.

    /**
     * @dev Penalize a relay that signed two transactions using the same nonce (making only the first one valid) and
     * different data (gas price, gas limit, etc. may be different).
     *
     * The (unsigned) transaction data and signature for both transactions must be provided.
     */
    function penalizeRepeatedNonce(bytes calldata unsignedTx1, bytes calldata signature1, bytes calldata unsignedTx2, bytes calldata signature2) external;

    /**
     * @dev Penalize a relay that sent a transaction that didn't target `RelayHub`'s {registerRelay} or {relayCall}.
     */
    function penalizeIllegalTransaction(bytes calldata unsignedTx, bytes calldata signature) external;

    /**
     * @dev Emitted when a relay is penalized.
     */
    event Penalized(address indexed relay, address sender, uint256 amount);

    /**
     * @dev Returns an account's nonce in `RelayHub`.
     */
    function getNonce(address from) external view returns (uint256);
}

pragma solidity ^0.5.17;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/cryptography/ECDSA.sol";
import "@openzeppelin/upgrades/contracts/upgradeability/InitializableAdminUpgradeabilityProxy.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol";

import "../Governance/Claimable.sol";
import "../libraries/String.sol";
import "./RenERC20.sol";
import "./interfaces/IGateway.sol";
import "../libraries/CanReclaimTokens.sol";

import "./MintGatewayV2.sol";
import "../Governance/RenProxyAdmin.sol";

contract MintGatewayUpgrader is Ownable, CanReclaimTokens {
    RenProxyAdmin renProxyAdmin;
    MintGatewayLogicV2 newGatewayLogic;
    address previousAdminOwner;
    address newMintAuthority;

    constructor(
        RenProxyAdmin _renProxyAdmin,
        MintGatewayLogicV2 _newGatewayLogic,
        address _newMintAuthority
    ) public {
        Ownable.initialize(msg.sender);
        renProxyAdmin = _renProxyAdmin;
        newGatewayLogic = _newGatewayLogic;
        previousAdminOwner = renProxyAdmin.owner();
        newMintAuthority = _newMintAuthority;
    }

    function upgrade(MintGatewayLogicV2 gatewayInstance, bytes32 selectorHash)
        public
        onlyOwner
    {
        uint256 minimumBurnAmount = gatewayInstance.minimumBurnAmount();
        RenERC20LogicV1 token = gatewayInstance.token();
        address mintAuthority = gatewayInstance.mintAuthority();
        address feeRecipient = gatewayInstance.feeRecipient();
        uint16 mintFee = gatewayInstance.mintFee();
        uint16 burnFee = gatewayInstance.burnFee();
        uint256 nextN = gatewayInstance.nextN();

        address previousGatewayOwner = gatewayInstance.owner();
        gatewayInstance.claimOwnership();

        // Update implementation.
        renProxyAdmin.upgrade(
            AdminUpgradeabilityProxy(
                // Cast gateway instance to payable address
                address(uint160(address(gatewayInstance)))
            ),
            address(newGatewayLogic)
        );

        // Update mint authorities and selector hash.
        address legacyMintAuthority = gatewayInstance.mintAuthority();
        gatewayInstance.updateMintAuthority(newMintAuthority);
        gatewayInstance._legacy_updateMintAuthority(legacyMintAuthority);
        gatewayInstance.updateSelectorHash(selectorHash);

        require(
            gatewayInstance.minimumBurnAmount() == minimumBurnAmount,
            "Expected minimumBurnAmount to not change."
        );
        require(
            gatewayInstance.token() == token,
            "Expected token to not change."
        );
        require(
            gatewayInstance._legacy_mintAuthority() == mintAuthority,
            "Expected _legacy_mintAuthority to equal old mintAuthority."
        );
        require(
            gatewayInstance.mintAuthority() == newMintAuthority,
            "Expected mintAuthority to equal new mintAuthority."
        );
        require(
            gatewayInstance.feeRecipient() == feeRecipient,
            "Expected feeRecipient to not change."
        );
        require(
            gatewayInstance.mintFee() == mintFee,
            "Expected mintFee to not change."
        );
        require(
            gatewayInstance.burnFee() == burnFee,
            "Expected burnFee to not change."
        );
        require(
            gatewayInstance.nextN() == nextN,
            "Expected nextN to not change."
        );

        gatewayInstance._directTransferOwnership(previousGatewayOwner);
    }

    function done() public onlyOwner {
        renProxyAdmin.transferOwnership(previousAdminOwner);
    }
}

pragma solidity ^0.5.17;

import "@openzeppelin/upgrades/contracts/upgradeability/ProxyAdmin.sol";

/**
 * @title RenProxyAdmin
 * @dev Proxies restrict the proxy's owner from calling functions from the
 * delegate contract logic. The ProxyAdmin contract allows single account to be
 * the governance address of both the proxy and the delegate contract logic.
 */
/* solium-disable-next-line no-empty-blocks */
contract RenProxyAdmin is ProxyAdmin {

}

pragma solidity ^0.5.0;

import "../ownership/Ownable.sol";
import "./AdminUpgradeabilityProxy.sol";

/**
 * @title ProxyAdmin
 * @dev This contract is the admin of a proxy, and is in charge
 * of upgrading it as well as transferring it to another admin.
 */
contract ProxyAdmin is OpenZeppelinUpgradesOwnable {
  
  /**
   * @dev Returns the current implementation of a proxy.
   * This is needed because only the proxy admin can query it.
   * @return The address of the current implementation of the proxy.
   */
  function getProxyImplementation(AdminUpgradeabilityProxy proxy) public view returns (address) {
    // We need to manually run the static call since the getter cannot be flagged as view
    // bytes4(keccak256("implementation()")) == 0x5c60da1b
    (bool success, bytes memory returndata) = address(proxy).staticcall(hex"5c60da1b");
    require(success);
    return abi.decode(returndata, (address));
  }

  /**
   * @dev Returns the admin of a proxy. Only the admin can query it.
   * @return The address of the current admin of the proxy.
   */
  function getProxyAdmin(AdminUpgradeabilityProxy proxy) public view returns (address) {
    // We need to manually run the static call since the getter cannot be flagged as view
    // bytes4(keccak256("admin()")) == 0xf851a440
    (bool success, bytes memory returndata) = address(proxy).staticcall(hex"f851a440");
    require(success);
    return abi.decode(returndata, (address));
  }

  /**
   * @dev Changes the admin of a proxy.
   * @param proxy Proxy to change admin.
   * @param newAdmin Address to transfer proxy administration to.
   */
  function changeProxyAdmin(AdminUpgradeabilityProxy proxy, address newAdmin) public onlyOwner {
    proxy.changeAdmin(newAdmin);
  }

  /**
   * @dev Upgrades a proxy to the newest implementation of a contract.
   * @param proxy Proxy to be upgraded.
   * @param implementation the address of the Implementation.
   */
  function upgrade(AdminUpgradeabilityProxy proxy, address implementation) public onlyOwner {
    proxy.upgradeTo(implementation);
  }

  /**
   * @dev Upgrades a proxy to the newest implementation of a contract and forwards a function call to it.
   * This is useful to initialize the proxied contract.
   * @param proxy Proxy to be upgraded.
   * @param implementation Address of the Implementation.
   * @param data Data to send as msg.data in the low level call.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   */
  function upgradeAndCall(AdminUpgradeabilityProxy proxy, address implementation, bytes memory data) payable public onlyOwner {
    proxy.upgradeToAndCall.value(msg.value)(implementation, data);
  }
}

pragma solidity ^0.5.0;

/**
 * @title Ownable
 * @dev The Ownable contract has an owner address, and provides basic authorization control
 * functions, this simplifies the implementation of "user permissions".
 *
 * Source https://raw.githubusercontent.com/OpenZeppelin/openzeppelin-solidity/v2.1.3/contracts/ownership/Ownable.sol
 * This contract is copied here and renamed from the original to avoid clashes in the compiled artifacts
 * when the user imports a zos-lib contract (that transitively causes this contract to be compiled and added to the
 * build/artifacts folder) as well as the vanilla Ownable implementation from an openzeppelin version.
 */
contract OpenZeppelinUpgradesOwnable {
    address private _owner;

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

    /**
     * @dev The Ownable constructor sets the original `owner` of the contract to the sender
     * account.
     */
    constructor () internal {
        _owner = msg.sender;
        emit OwnershipTransferred(address(0), _owner);
    }

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(isOwner());
        _;
    }

    /**
     * @return true if `msg.sender` is the owner of the contract.
     */
    function isOwner() public view returns (bool) {
        return msg.sender == _owner;
    }

    /**
     * @dev Allows the current owner to relinquish control of the contract.
     * @notice Renouncing to ownership will leave the contract without an owner.
     * It will not be possible to call the functions with the `onlyOwner`
     * modifier anymore.
     */
    function renounceOwnership() public onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Allows the current owner to transfer control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function transferOwnership(address newOwner) public onlyOwner {
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers control of the contract to a newOwner.
     * @param newOwner The address to transfer ownership to.
     */
    function _transferOwnership(address newOwner) internal {
        require(newOwner != address(0));
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

pragma solidity ^0.5.0;

import './BaseAdminUpgradeabilityProxy.sol';

/**
 * @title AdminUpgradeabilityProxy
 * @dev Extends from BaseAdminUpgradeabilityProxy with a constructor for 
 * initializing the implementation, admin, and init data.
 */
contract AdminUpgradeabilityProxy is BaseAdminUpgradeabilityProxy, UpgradeabilityProxy {
  /**
   * Contract constructor.
   * @param _logic address of the initial implementation.
   * @param _admin Address of the proxy administrator.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  constructor(address _logic, address _admin, bytes memory _data) UpgradeabilityProxy(_logic, _data) public payable {
    assert(ADMIN_SLOT == bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1));
    _setAdmin(_admin);
  }
}

pragma solidity ^0.5.17;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/cryptography/ECDSA.sol";
import "@openzeppelin/upgrades/contracts/upgradeability/InitializableAdminUpgradeabilityProxy.sol";

import "../Governance/Claimable.sol";
import "../libraries/String.sol";
import "./RenERC20.sol";
import "./interfaces/IGateway.sol";
import "../libraries/CanReclaimTokens.sol";

contract LockGatewayStateV1 {
    uint256 constant BIPS_DENOMINATOR = 10000;
    uint256 public minimumBurnAmount;

    /// @notice Each Gateway is tied to a specific RenERC20 token.
    RenERC20LogicV1 public token;

    /// @notice The mintAuthority is an address that can sign mint requests.
    address public mintAuthority;

    /// @dev feeRecipient is assumed to be an address (or a contract) that can
    /// accept erc20 payments it cannot be 0x0.
    /// @notice When tokens are mint or burnt, a portion of the tokens are
    /// forwarded to a fee recipient.
    address public feeRecipient;

    /// @notice The mint fee in bips.
    uint16 public lockFee;

    /// @notice The burn fee in bips.
    uint16 public releaseFee;

    /// @notice Each signature can only be seen once.
    mapping(bytes32 => bool) public status;

    // LogMint and LogBurn contain a unique `n` that identifies
    // the mint or burn event.
    uint256 public nextN = 0;
}

/// @notice Gateway handles verifying mint and burn requests. A mintAuthority
/// approves new assets to be minted by providing a digital signature. An owner
/// of an asset can request for it to be burnt.
contract LockGatewayLogicV1 is
    Initializable,
    Claimable,
    CanReclaimTokens,
    // ILock,
    LockGatewayStateV1
{
    using SafeMath for uint256;

    event LogMintAuthorityUpdated(address indexed _newMintAuthority);
    event LogLock(
        bytes _to,
        bytes _p,
        uint256 _amount,
        uint256 indexed _n,
        bytes indexed _indexedTo
    );
    event LogRelease(
        address indexed _to,
        uint256 _amount,
        uint256 indexed _n,
        bytes32 indexed _signedMessageHash
    );

    /// @notice Only allow the Darknode Payment contract.
    modifier onlyOwnerOrMintAuthority() {
        require(
            msg.sender == mintAuthority || msg.sender == owner(),
            "Gateway: caller is not the owner or mint authority"
        );
        _;
    }

    /// @param _token The RenERC20 this Gateway is responsible for.
    /// @param _feeRecipient The recipient of burning and minting fees.
    /// @param _mintAuthority The address of the key that can sign mint
    ///        requests.
    /// @param _lockFee The amount subtracted each mint request and
    ///        forwarded to the feeRecipient. In BIPS.
    /// @param _releaseFee The amount subtracted each burn request and
    ///        forwarded to the feeRecipient. In BIPS.
    function initialize(
        RenERC20LogicV1 _token,
        address _feeRecipient,
        address _mintAuthority,
        uint16 _lockFee,
        uint16 _releaseFee,
        uint256 _minimumBurnAmount
    ) public initializer {
        Claimable.initialize(msg.sender);
        CanReclaimTokens.initialize(msg.sender);
        minimumBurnAmount = _minimumBurnAmount;
        token = _token;
        lockFee = _lockFee;
        releaseFee = _releaseFee;
        updateMintAuthority(_mintAuthority);
        updateFeeRecipient(_feeRecipient);
    }

    // Public functions ////////////////////////////////////////////////////////

    /// @notice Claims ownership of the token passed in to the constructor.
    /// `transferStoreOwnership` must have previously been called.
    /// Anyone can call this function.
    function claimTokenOwnership() public {
        token.claimOwnership();
    }

    /// @notice Allow the owner to update the fee recipient.
    ///
    /// @param _nextMintAuthority The address to start paying fees to.
    function updateMintAuthority(address _nextMintAuthority)
        public
        onlyOwnerOrMintAuthority
    {
        // The mint authority should not be set to 0, which is the result
        // returned by ecrecover for an invalid signature.
        require(
            _nextMintAuthority != address(0),
            "Gateway: mintAuthority cannot be set to address zero"
        );
        mintAuthority = _nextMintAuthority;
        emit LogMintAuthorityUpdated(mintAuthority);
    }

    /// @notice Allow the owner to update the fee recipient.
    ///
    /// @param _nextFeeRecipient The address to start paying fees to.
    function updateFeeRecipient(address _nextFeeRecipient) public onlyOwner {
        // 'mint' and 'burn' will fail if the feeRecipient is 0x0
        require(
            _nextFeeRecipient != address(0x0),
            "Gateway: fee recipient cannot be 0x0"
        );

        feeRecipient = _nextFeeRecipient;
    }

    /// @notice Allow the owner to update the 'mint' fee.
    ///
    /// @param _nextLockFee The new fee for locking.
    function updateLockFee(uint16 _nextLockFee) public onlyOwner {
        lockFee = _nextLockFee;
    }

    /// @notice Allow the owner to update the burn fee.
    ///
    /// @param _nextReleaseFee The new fee for releasing.
    function updateReleaseFee(uint16 _nextReleaseFee) public onlyOwner {
        releaseFee = _nextReleaseFee;
    }

    function lock(
        string memory _chain,
        bytes memory _to,
        bytes memory _payload,
        uint256 _amount
    ) public returns (uint256) {
        require(token.transferFrom(msg.sender, address(this), _amount));
        uint256 fee = _amount.mul(lockFee).div(BIPS_DENOMINATOR);
        token.transfer(feeRecipient, fee);
        uint256 amountAfterFee = _amount.sub(fee);
        emit LogLock(_to, _payload, amountAfterFee, nextN, _to);
        nextN += 1;
        return amountAfterFee;
    }

    /// @notice release verifies a release approval signature from RenVM and
    ///         sends tokens after taking a fee for the `_feeRecipient`.
    ///
    /// @param _pHash (payload hash) The hash of the payload associated with the
    ///        release.
    /// @param _amount The amount of the token being released, in its smallest
    ///        value. (e.g. satoshis for BTC).
    /// @param _nHash (nonce hash) The hash of the nonce, amount and pHash.
    /// @param _sig The signature of the hash of the following values:
    ///        (pHash, amount, msg.sender, nHash), signed by the mintAuthority.
    function release(
        bytes32 _pHash,
        uint256 _amount,
        bytes32 _nHash,
        bytes memory _sig
    ) public returns (uint256) {
        // Verify signature
        bytes32 signedMessageHash = hashForSignature(
            _pHash,
            _amount,
            msg.sender,
            _nHash
        );
        require(
            status[signedMessageHash] == false,
            "Gateway: nonce hash already spent"
        );
        if (!verifySignature(signedMessageHash, _sig)) {
            // Return a detailed string containing the hash and recovered
            // signer. This is somewhat costly but is only run in the revert
            // branch.
            revert(
                String.add8(
                    "Gateway: invalid signature. pHash: ",
                    String.fromBytes32(_pHash),
                    ", amount: ",
                    String.fromUint(_amount),
                    ", msg.sender: ",
                    String.fromAddress(msg.sender),
                    ", _nHash: ",
                    String.fromBytes32(_nHash)
                )
            );
        }
        status[signedMessageHash] = true;

        uint256 fee = _amount.mul(releaseFee).div(BIPS_DENOMINATOR);
        uint256 amountAfterFee = _amount.sub(fee);

        // Mint amount minus the fee
        token.transfer(msg.sender, fee);
        // Mint the fee
        token.transfer(feeRecipient, amountAfterFee);

        emit LogRelease(msg.sender, amountAfterFee, nextN, signedMessageHash);
        nextN += 1;

        return amountAfterFee;
    }

    /// @notice verifySignature checks the the provided signature matches the provided
    /// parameters.
    function verifySignature(bytes32 _signedMessageHash, bytes memory _sig)
        public
        view
        returns (bool)
    {
        return mintAuthority == ECDSA.recover(_signedMessageHash, _sig);
    }

    /// @notice hashForSignature hashes the parameters so that they can be signed.
    function hashForSignature(
        bytes32 _pHash,
        uint256 _amount,
        address _to,
        bytes32 _nHash
    ) public view returns (bytes32) {
        return
            keccak256(abi.encode(_pHash, _amount, address(token), _to, _nHash));
    }
}

/* solium-disable-next-line no-empty-blocks */
contract LockGatewayProxy is InitializableAdminUpgradeabilityProxy {

}

pragma solidity ^0.5.17;

import "../GatewayRegistry.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/Math.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol";

contract Vesting is Ownable {
    using SafeMath for uint256;

    GatewayRegistry public registry;

    uint256 private constant SECONDS_PER_MONTH = 365 days / 12;

    /// @notice Defines the fields required for a vesting schedule.
    struct VestingSchedule {
        // The start time (in seconds since Unix epoch) at which the vesting
        // period should begin.
        uint256 startTime;
        // The number of months for the vesting period.
        uint16 duration;
        // The total amount of Bitcoin apart of the vesting schedule.
        uint256 amount;
        // The number of months claimed by the user.
        uint256 monthsClaimed;
        // The total amount of Bitcoin claimed by the user.
        uint256 amountClaimed;
    }

    /// @notice Mapping of a beneficiary address to a vesting schedule. Each
    //          beneficiary can have a maximum of 1 vesting schedule.
    mapping(address => VestingSchedule) public schedules;

    /// @notice The contract constructor.
    /// @param _registry The GatewayRegistry contract address.
    constructor(GatewayRegistry _registry) public {
        Ownable.initialize(msg.sender);
        registry = _registry;
    }

    /// @notice Allows the contract owner to add a vesting schedule for a
    ///         beneficiary.
    /// @param _amount The amount of Bitcoin provided to the Darknodes in Sats.
    /// @param _nHash The hash of the nonce returned by the Darknodes.
    /// @param _sig The signature returned by the Darknodes.
    /// @param _beneficiary The address of the recipient entitled to claim the vested tokens.
    /// @param _startTime The start time (in seconds since Unix epoch) at which the vesting
    ///                   period should begin.
    /// @param _duration The number of months for the vesting period.
    function addVestingSchedule(
        // Payload
        address _beneficiary,
        uint256 _startTime,
        uint16 _duration,
        // Required
        uint256 _amount,
        bytes32 _nHash,
        bytes calldata _sig
    ) external onlyOwner {
        require(
            schedules[_beneficiary].startTime == 0,
            "vesting schedule already exists"
        );
        require(_amount > 0, "amount must be greater than 0");
        require(_duration > 0, "duration must be at least 1 month");

        // Construct the payload hash and mint new tokens using the Gateway
        // contract. This will verify the signature to ensure the Darknodes have
        // received the Bitcoin.
        bytes32 pHash =
            keccak256(abi.encode(_beneficiary, _startTime, _duration));
        uint256 finalAmountScaled =
            registry.getGatewayBySymbol("BTC").mint(
                pHash,
                _amount,
                _nHash,
                _sig
            );

        // Construct a vesting schedule and assign it to the beneficiary.
        VestingSchedule memory schedule =
            VestingSchedule({
                startTime: _startTime == 0 ? now : _startTime,
                duration: _duration,
                amount: finalAmountScaled,
                monthsClaimed: 0,
                amountClaimed: 0
            });

        schedules[_beneficiary] = schedule;
    }

    /// @notice Allows a beneficiary to withdraw their vested Bitcoin.
    /// @param _to The Bitcoin address to which the beneficiary will receive
    ///            their Bitcoin.
    function claim(bytes calldata _to) external {
        // Calculate the claimable amount for the caller of the function.
        uint256 monthsClaimable;
        uint256 amountClaimable;
        (monthsClaimable, amountClaimable) = calculateClaimable(msg.sender);

        require(amountClaimable > 0, "no amount claimable");

        // Update the claimed details in the vesting schedule.
        VestingSchedule storage schedule = schedules[msg.sender];
        schedule.monthsClaimed = schedule.monthsClaimed.add(monthsClaimable);
        schedule.amountClaimed = schedule.amountClaimed.add(amountClaimable);

        // Burn the tokens using the Gateway contract. This will burn the
        // tokens after taking a fee. The Darknodes will watch for this event to
        // transfer the user the Bitcoin.
        registry.getGatewayBySymbol("BTC").burn(_to, amountClaimable);
    }

    /// @notice Retrieves the claimable amount for a given beneficiary.
    /// @param _to The Ethereum address of the beneficiary.
    function calculateClaimable(address _to)
        public
        view
        returns (uint256, uint256)
    {
        VestingSchedule storage schedule = schedules[_to];

        // Return if the vesting schedule does not exist or has not yet started.
        if (schedule.amount == 0 || now < schedule.startTime) {
            return (0, 0);
        }

        // Calculate the months elapsed since the start of the vesting period.
        uint256 elapsedTime = now.sub(schedule.startTime);
        uint256 elapsedMonths = elapsedTime.div(SECONDS_PER_MONTH);

        // Calculate the months elapsed and amount claimable since the last
        // claim attempt.
        uint256 monthsClaimable =
            Math.min(schedule.duration, elapsedMonths).sub(
                schedule.monthsClaimed
            );
        uint256 amountClaimable =
            schedule.amount.mul(monthsClaimable).div(schedule.duration);

        return (monthsClaimable, amountClaimable);
    }
}

pragma solidity ^0.5.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}

pragma solidity ^0.5.17;

import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/ownership/Ownable.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC721/IERC721Receiver.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC777/IERC777Recipient.sol";
import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC777/IERC777.sol";

import "../interfaces/IGateway.sol";
import "../interfaces/IGatewayRegistry.sol";
import "./IERC1155/IERC1155.sol";
import "./IERC1155/IERC1155Receiver.sol";

contract GenericAdapter is
    Ownable,
    IERC721Receiver,
    IERC777Recipient,
    IERC1155Receiver
{
    using SafeMath for uint256;

    IGatewayRegistry public registry;

    constructor(IGatewayRegistry _registry) public {
        Ownable.initialize(msg.sender);
        registry = _registry;
    }

    function directMint(
        // Payload
        string calldata _symbol,
        address _account,
        uint256 _submitterFee,
        // Required
        uint256 _amount,
        bytes32 _nHash,
        bytes calldata _sig
    ) external {
        // Allow the account to submit without a fee.
        if (_account == msg.sender) {
            _submitterFee = 0;
        }

        // Calculate the payload hash for the first six parameters.
        bytes32 payloadHash =
            keccak256(abi.encode(_symbol, _account, _submitterFee));

        // Call `mint` on the Gateway contract.
        uint256 amount =
            registry.getGatewayBySymbol(_symbol).mint(
                payloadHash,
                _amount,
                _nHash,
                _sig
            );

        IERC20 token = registry.getTokenBySymbol(_symbol);
        token.transfer(_account, amount.sub(_submitterFee));

        // Pay fee as last step.
        if (_submitterFee > 0) {
            token.transfer(msg.sender, _submitterFee);
        }
    }

    // Track the caller in case there's ERC721
    address currentAccount;

    function genericCall(
        // Payload
        string calldata _symbol,
        address _account,
        address _contract,
        bytes calldata _contractParams,
        IERC20[] calldata _refundTokens,
        uint256 _submitterFee,
        // Required
        uint256 _amount,
        bytes32 _nHash,
        bytes calldata _sig
    ) external {
        address previousAccount = currentAccount;
        currentAccount = _account;

        // Split up to work around stack-too-deep errors.
        // The function body is spread across the following three functions:
        // * _genericCallInner,
        // * _returnReceivedTokens,
        // * _mintAndCall
        _genericCallInner(
            _symbol,
            _account,
            _contract,
            _contractParams,
            _refundTokens,
            _submitterFee,
            _amount,
            _nHash,
            _sig
        );

        // Reset `currentAccount`.
        currentAccount = previousAccount;
    }

    function _genericCallInner(
        // Payload
        string memory _symbol,
        address _account,
        address _contract,
        bytes memory _contractParams,
        IERC20[] memory _refundTokens,
        uint256 _submitterFee,
        // Required
        uint256 _amount,
        bytes32 _nHash,
        bytes memory _sig
    ) internal {
        // Allow the account to submit without a fee.
        if (_account == msg.sender) {
            _submitterFee = 0;
        }

        // Calculate the payload hash for the first six parameters.
        bytes32 payloadHash =
            keccak256(
                abi.encode(
                    _symbol,
                    _account,
                    _contract,
                    _contractParams,
                    _refundTokens,
                    _submitterFee
                )
            );

        _mintAndCall(
            payloadHash,
            _symbol,
            _contract,
            _contractParams,
            _submitterFee,
            _amount,
            _nHash,
            _sig
        );

        _returnReceivedTokens(_symbol, _refundTokens, _submitterFee);
    }

    function _returnReceivedTokens(
        string memory _symbol,
        IERC20[] memory _refundTokens,
        uint256 _submitterFee
    ) internal {
        IERC20 token = registry.getTokenBySymbol(_symbol);

        // The user must specify which tokens may potentially be recieved during
        // the contract call. Note that if one of the matched refund tokens
        // match `token` and a fee is paid out later on, the transaction will
        // revert.
        for (uint256 i = 0; i < _refundTokens.length; i++) {
            IERC20 refundToken = IERC20(_refundTokens[i]);
            uint256 refundBalance = refundToken.balanceOf(address(this));
            if (refundBalance > 0) {
                refundToken.transfer(currentAccount, refundBalance);
            }
        }

        // Return any remaining `token` balance.
        uint256 tokenBalance = token.balanceOf(address(this));
        if (tokenBalance > _submitterFee) {
            token.transfer(currentAccount, tokenBalance.sub(_submitterFee));
        }

        // Remain any remaining ETH balance.
        uint256 ethBalance = address(this).balance;
        if (ethBalance > 0) {
            (bool success, ) = currentAccount.call.value(ethBalance)("");
            require(success);
        }

        // Pay fee as last step.
        if (_submitterFee > 0) {
            token.transfer(msg.sender, _submitterFee);
        }
    }

    function _mintAndCall(
        bytes32 payloadHash,
        string memory _symbol,
        address _contract,
        bytes memory _contractParams,
        uint256 _submitterFee,
        uint256 _amount,
        bytes32 _nHash,
        bytes memory _sig
    ) internal {
        // Call `mint` on the Gateway contract.
        uint256 amount =
            registry.getGatewayBySymbol(_symbol).mint(
                payloadHash,
                _amount,
                _nHash,
                _sig
            );

        IERC20 token = registry.getTokenBySymbol(_symbol);

        // Approval the amount excluding the fee.
        uint256 oldApproval = token.allowance(address(this), _contract);
        token.approve(_contract, oldApproval.add(amount.sub(_submitterFee)));

        // Call contract with the contract parameters.
        arbitraryCall(_contract, _contractParams);

        // Revoke approval.
        token.approve(_contract, oldApproval);
    }

    function onERC721Received(
        address,
        address,
        uint256 tokenId,
        bytes memory data
    ) public returns (bytes4) {
        // Forward on to current account.
        IERC721(msg.sender).safeTransferFrom(
            address(this),
            currentAccount,
            tokenId,
            data
        );
        return this.onERC721Received.selector;
    }

    function tokensReceived(
        address,
        address,
        address,
        uint256 amount,
        bytes memory userData,
        bytes memory
    ) public {
        IERC777(msg.sender).send(currentAccount, amount, userData);
    }

    function onERC1155Received(
        address,
        address,
        uint256 id,
        uint256 value,
        bytes calldata data
    ) external returns (bytes4) {
        IERC1155(msg.sender).safeTransferFrom(
            address(this),
            currentAccount,
            id,
            value,
            data
        );
        return this.onERC1155Received.selector;
    }

    function onERC1155BatchReceived(
        address,
        address,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    ) external returns (bytes4) {
        IERC1155(msg.sender).safeBatchTransferFrom(
            address(this),
            currentAccount,
            ids,
            values,
            data
        );
        return this.onERC1155BatchReceived.selector;
    }

    // Allow the owner to recover tokens and collectibles stuck in the contract.
    // This contract is not meant to hold funds.
    function _recover(address _contract, bytes calldata _contractParams)
        external
        onlyOwner
    {
        arbitraryCall(_contract, _contractParams);
    }

    function arbitraryCall(address _contract, bytes memory _contractParams)
        internal
    {
        (bool success, bytes memory result) = _contract.call(_contractParams);
        if (!success) {
            // Check if the call result was too short to be a revert reason.
            if (result.length < 68) {
                revert(
                    "GenericAdapter: contract call failed without revert reason"
                );
            }
            // Return the call's revert reason.
            assembly {
                let ptr := mload(0x40)
                let size := returndatasize
                returndatacopy(ptr, 0, size)
                revert(ptr, size)
            }
        }
    }
}

pragma solidity ^0.5.0;

/**
 * @title ERC721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC721 asset contracts.
 */
contract IERC721Receiver {
    /**
     * @notice Handle the receipt of an NFT
     * @dev The ERC721 smart contract calls this function on the recipient
     * after a {IERC721-safeTransferFrom}. This function MUST return the function selector,
     * otherwise the caller will revert the transaction. The selector to be
     * returned can be obtained as `this.onERC721Received.selector`. This
     * function MAY throw to revert and reject the transfer.
     * Note: the ERC721 contract address is always the message sender.
     * @param operator The address which called `safeTransferFrom` function
     * @param from The address which previously owned the token
     * @param tokenId The NFT identifier which is being transferred
     * @param data Additional data with no specified format
     * @return bytes4 `bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"))`
     */
    function onERC721Received(address operator, address from, uint256 tokenId, bytes memory data)
    public returns (bytes4);
}

pragma solidity ^0.5.0;

import "@openzeppelin/upgrades/contracts/Initializable.sol";
import "../../introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC721 compliant contract.
 */
contract IERC721 is Initializable, IERC165 {
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of NFTs in `owner`'s account.
     */
    function balanceOf(address owner) public view returns (uint256 balance);

    /**
     * @dev Returns the owner of the NFT specified by `tokenId`.
     */
    function ownerOf(uint256 tokenId) public view returns (address owner);

    /**
     * @dev Transfers a specific NFT (`tokenId`) from one account (`from`) to
     * another (`to`).
     *
     *
     *
     * Requirements:
     * - `from`, `to` cannot be zero.
     * - `tokenId` must be owned by `from`.
     * - If the caller is not `from`, it must be have been allowed to move this
     * NFT by either {approve} or {setApprovalForAll}.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) public;
    /**
     * @dev Transfers a specific NFT (`tokenId`) from one account (`from`) to
     * another (`to`).
     *
     * Requirements:
     * - If the caller is not `from`, it must be approved to move this NFT by
     * either {approve} or {setApprovalForAll}.
     */
    function transferFrom(address from, address to, uint256 tokenId) public;
    function approve(address to, uint256 tokenId) public;
    function getApproved(uint256 tokenId) public view returns (address operator);

    function setApprovalForAll(address operator, bool _approved) public;
    function isApprovedForAll(address owner, address operator) public view returns (bool);


    function safeTransferFrom(address from, address to, uint256 tokenId, bytes memory data) public;
}

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC777TokensRecipient standard as defined in the EIP.
 *
 * Accounts can be notified of {IERC777} tokens being sent to them by having a
 * contract implement this interface (contract holders can be their own
 * implementer) and registering it on the
 * https://eips.ethereum.org/EIPS/eip-1820[ERC1820 global registry].
 *
 * See {IERC1820Registry} and {ERC1820Implementer}.
 */
interface IERC777Recipient {
    /**
     * @dev Called by an {IERC777} token contract whenever tokens are being
     * moved or created into a registered account (`to`). The type of operation
     * is conveyed by `from` being the zero address or not.
     *
     * This call occurs _after_ the token contract's state is updated, so
     * {IERC777-balanceOf}, etc., can be used to query the post-operation state.
     *
     * This function may revert to prevent the operation from being executed.
     */
    function tokensReceived(
        address operator,
        address from,
        address to,
        uint256 amount,
        bytes calldata userData,
        bytes calldata operatorData
    ) external;
}

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC777Token standard as defined in the EIP.
 *
 * This contract uses the
 * https://eips.ethereum.org/EIPS/eip-1820[ERC1820 registry standard] to let
 * token holders and recipients react to token movements by using setting implementers
 * for the associated interfaces in said registry. See {IERC1820Registry} and
 * {ERC1820Implementer}.
 */
interface IERC777 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the smallest part of the token that is not divisible. This
     * means all token operations (creation, movement and destruction) must have
     * amounts that are a multiple of this number.
     *
     * For most token contracts, this value will equal 1.
     */
    function granularity() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * If send or receive hooks are registered for the caller and `recipient`,
     * the corresponding functions will be called with `data` and empty
     * `operatorData`. See {IERC777Sender} and {IERC777Recipient}.
     *
     * Emits a {Sent} event.
     *
     * Requirements
     *
     * - the caller must have at least `amount` tokens.
     * - `recipient` cannot be the zero address.
     * - if `recipient` is a contract, it must implement the {IERC777Recipient}
     * interface.
     */
    function send(address recipient, uint256 amount, bytes calldata data) external;

    /**
     * @dev Destroys `amount` tokens from the caller's account, reducing the
     * total supply.
     *
     * If a send hook is registered for the caller, the corresponding function
     * will be called with `data` and empty `operatorData`. See {IERC777Sender}.
     *
     * Emits a {Burned} event.
     *
     * Requirements
     *
     * - the caller must have at least `amount` tokens.
     */
    function burn(uint256 amount, bytes calldata data) external;

    /**
     * @dev Returns true if an account is an operator of `tokenHolder`.
     * Operators can send and burn tokens on behalf of their owners. All
     * accounts are their own operator.
     *
     * See {operatorSend} and {operatorBurn}.
     */
    function isOperatorFor(address operator, address tokenHolder) external view returns (bool);

    /**
     * @dev Make an account an operator of the caller.
     *
     * See {isOperatorFor}.
     *
     * Emits an {AuthorizedOperator} event.
     *
     * Requirements
     *
     * - `operator` cannot be calling address.
     */
    function authorizeOperator(address operator) external;

    /**
     * @dev Make an account an operator of the caller.
     *
     * See {isOperatorFor} and {defaultOperators}.
     *
     * Emits a {RevokedOperator} event.
     *
     * Requirements
     *
     * - `operator` cannot be calling address.
     */
    function revokeOperator(address operator) external;

    /**
     * @dev Returns the list of default operators. These accounts are operators
     * for all token holders, even if {authorizeOperator} was never called on
     * them.
     *
     * This list is immutable, but individual holders may revoke these via
     * {revokeOperator}, in which case {isOperatorFor} will return false.
     */
    function defaultOperators() external view returns (address[] memory);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient`. The caller must
     * be an operator of `sender`.
     *
     * If send or receive hooks are registered for `sender` and `recipient`,
     * the corresponding functions will be called with `data` and
     * `operatorData`. See {IERC777Sender} and {IERC777Recipient}.
     *
     * Emits a {Sent} event.
     *
     * Requirements
     *
     * - `sender` cannot be the zero address.
     * - `sender` must have at least `amount` tokens.
     * - the caller must be an operator for `sender`.
     * - `recipient` cannot be the zero address.
     * - if `recipient` is a contract, it must implement the {IERC777Recipient}
     * interface.
     */
    function operatorSend(
        address sender,
        address recipient,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    ) external;

    /**
     * @dev Destoys `amount` tokens from `account`, reducing the total supply.
     * The caller must be an operator of `account`.
     *
     * If a send hook is registered for `account`, the corresponding function
     * will be called with `data` and `operatorData`. See {IERC777Sender}.
     *
     * Emits a {Burned} event.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     * - the caller must be an operator for `account`.
     */
    function operatorBurn(
        address account,
        uint256 amount,
        bytes calldata data,
        bytes calldata operatorData
    ) external;

    event Sent(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256 amount,
        bytes data,
        bytes operatorData
    );

    event Minted(address indexed operator, address indexed to, uint256 amount, bytes data, bytes operatorData);

    event Burned(address indexed operator, address indexed from, uint256 amount, bytes data, bytes operatorData);

    event AuthorizedOperator(address indexed operator, address indexed tokenHolder);

    event RevokedOperator(address indexed operator, address indexed tokenHolder);
}

pragma solidity ^0.5.17;

import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol";

import "./IGateway.sol";

/// @notice GatewayRegistry is a mapping from assets to their associated
/// RenERC20 and Gateway contracts.
interface IGatewayRegistry {
    /// @dev The symbol is included twice because strings have to be hashed
    /// first in order to be used as a log index/topic.
    event LogGatewayRegistered(
        string _symbol,
        string indexed _indexedSymbol,
        address indexed _tokenAddress,
        address indexed _gatewayAddress
    );
    event LogGatewayDeregistered(
        string _symbol,
        string indexed _indexedSymbol,
        address indexed _tokenAddress,
        address indexed _gatewayAddress
    );
    event LogGatewayUpdated(
        address indexed _tokenAddress,
        address indexed _currentGatewayAddress,
        address indexed _newGatewayAddress
    );

    /// @dev To get all the registered gateways use count = 0.
    function getGateways(address _start, uint256 _count)
        external
        view
        returns (address[] memory);

    /// @dev To get all the registered RenERC20s use count = 0.
    function getRenTokens(address _start, uint256 _count)
        external
        view
        returns (address[] memory);

    /// @notice Returns the Gateway contract for the given RenERC20
    ///         address.
    ///
    /// @param _tokenAddress The address of the RenERC20 contract.
    function getGatewayByToken(address _tokenAddress)
        external
        view
        returns (IGateway);

    /// @notice Returns the Gateway contract for the given RenERC20
    ///         symbol.
    ///
    /// @param _tokenSymbol The symbol of the RenERC20 contract.
    function getGatewayBySymbol(string calldata _tokenSymbol)
        external
        view
        returns (IGateway);

    /// @notice Returns the RenERC20 address for the given token symbol.
    ///
    /// @param _tokenSymbol The symbol of the RenERC20 contract to
    ///        lookup.
    function getTokenBySymbol(string calldata _tokenSymbol)
        external
        view
        returns (IERC20);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.5.17;

/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256 id,
        uint256 value
    );

    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(
        address indexed operator,
        address indexed from,
        address indexed to,
        uint256[] ids,
        uint256[] values
    );

    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(
        address indexed account,
        address indexed operator,
        bool approved
    );

    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);

    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id)
        external
        view
        returns (uint256);

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids)
        external
        view
        returns (uint256[] memory);

    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator)
        external
        view
        returns (bool);

    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(
        address from,
        address to,
        uint256 id,
        uint256 amount,
        bytes calldata data
    ) external;

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(
        address from,
        address to,
        uint256[] calldata ids,
        uint256[] calldata amounts,
        bytes calldata data
    ) external;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.5.17;

/**
 * _Available since v3.1._
 */
interface IERC1155Receiver {
    /**
        @dev Handles the receipt of a single ERC1155 token type. This function is
        called at the end of a `safeTransferFrom` after the balance has been updated.
        To accept the transfer, this must return
        `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))`
        (i.e. 0xf23a6e61, or its own function selector).
        @param operator The address which initiated the transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param id The ID of the token being transferred
        @param value The amount of tokens being transferred
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155Received(address,address,uint256,uint256,bytes)"))` if transfer is allowed
    */
    function onERC1155Received(
        address operator,
        address from,
        uint256 id,
        uint256 value,
        bytes calldata data
    ) external returns (bytes4);

    /**
        @dev Handles the receipt of a multiple ERC1155 token types. This function
        is called at the end of a `safeBatchTransferFrom` after the balances have
        been updated. To accept the transfer(s), this must return
        `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))`
        (i.e. 0xbc197c81, or its own function selector).
        @param operator The address which initiated the batch transfer (i.e. msg.sender)
        @param from The address which previously owned the token
        @param ids An array containing ids of each token being transferred (order and length must match values array)
        @param values An array containing amounts of each token being transferred (order and length must match ids array)
        @param data Additional data with no specified format
        @return `bytes4(keccak256("onERC1155BatchReceived(address,address,uint256[],uint256[],bytes)"))` if transfer is allowed
    */
    function onERC1155BatchReceived(
        address operator,
        address from,
        uint256[] calldata ids,
        uint256[] calldata values,
        bytes calldata data
    ) external returns (bytes4);
}

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

pragma solidity ^0.5.17;

import "@openzeppelin/contracts-ethereum-package/contracts/GSN/GSNRecipient.sol";

import "../interfaces/IGateway.sol";
import "../interfaces/IGatewayRegistry.sol";

contract BasicAdapter is GSNRecipient {
    IGatewayRegistry registry;

    constructor(IGatewayRegistry _registry) public {
        GSNRecipient.initialize();
        registry = _registry;
    }

    function mint(
        // Payload
        string calldata _symbol,
        address _recipient,
        // Required
        uint256 _amount,
        bytes32 _nHash,
        bytes calldata _sig
    ) external {
        bytes32 payloadHash = keccak256(abi.encode(_symbol, _recipient));
        uint256 amount = registry.getGatewayBySymbol(_symbol).mint(
            payloadHash,
            _amount,
            _nHash,
            _sig
        );
        registry.getTokenBySymbol(_symbol).transfer(_recipient, amount);
    }

    function burn(
        string calldata _symbol,
        bytes calldata _to,
        uint256 _amount
    ) external {
        require(
            registry.getTokenBySymbol(_symbol).transferFrom(
                _msgSender(),
                address(this),
                _amount
            ),
            "token transfer failed"
        );
        registry.getGatewayBySymbol(_symbol).burn(_to, _amount);
    }

    // GSN functions

    function acceptRelayedCall(
        address relay,
        address from,
        bytes calldata encodedFunction,
        uint256 transactionFee,
        uint256 gasPrice,
        uint256 gasLimit,
        uint256 nonce,
        bytes calldata approvalData,
        uint256 maxPossibleCharge
    ) external view returns (uint256, bytes memory) {
        return _approveRelayedCall();
    }

    // We won't do any pre or post processing, so leave _preRelayedCall and _postRelayedCall empty
    function _preRelayedCall(bytes memory context) internal returns (bytes32) {}

    function _postRelayedCall(
        bytes memory context,
        bool,
        uint256 actualCharge,
        bytes32
    ) internal {}
}

pragma solidity ^0.5.17;

import "@openzeppelin/contracts-ethereum-package/contracts/token/ERC20/IERC20.sol";
import "./GenericAdapter.sol";

interface UniswapRouter {
    function WETH() external returns (address);

    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
}

contract CallAndRefund {
    GenericAdapter public genericAdapter;
    UniswapRouter public uniswapRouter;
    IGatewayRegistry public registry;

    constructor(
        IGatewayRegistry _registry,
        GenericAdapter _genericAdapter,
        UniswapRouter _uniswapRouter
    ) public {
        registry = _registry;
        genericAdapter = _genericAdapter;
        uniswapRouter = _uniswapRouter;
    }

    modifier withGasRefund() {
        uint256 remainingGasStart = gasleft();

        _;

        uint256 ethBalance = address(this).balance;
        uint256 remainingGasEnd = gasleft();
        uint256 usedGas = remainingGasStart - remainingGasEnd;
        // Add intrinsic gas and transfer gas. Need to account for gas stipend as well.
        usedGas += 21000 + 9700;
        // Possibly need to check max gasprice and usedGas here to limit possibility for abuse.
        uint256 gasCost = usedGas * tx.gasprice;
        require(ethBalance >= gasCost, "GaslessWithUniswap: gas exceeds fee");
        // Refund gas cost
        msg.sender.transfer(ethBalance);
    }

    // Allow this contract to receive ETH.
    function receive() external payable {}

    function convertAllToEth(IERC20 token) public payable {
        address[] memory path = new address[](2);
        path[0] = address(token);
        path[1] = uniswapRouter.WETH();

        uint256 tokenBalance = token.balanceOf(address(this));
        token.approve(address(uniswapRouter), tokenBalance);
        uniswapRouter.swapExactTokensForETH(
            tokenBalance,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function callAndRefund(
        IERC20 _token,
        address _contract,
        bytes calldata _contractParams
    ) external withGasRefund {
        arbitraryCall(_contract, _contractParams);
        convertAllToEth(_token);
    }

    function arbitraryCall(address _contract, bytes memory _contractParams)
        internal
    {
        (bool success, bytes memory result) = _contract.call(_contractParams);
        if (!success) {
            // Check if the call result was too short to be a revert reason.
            if (result.length < 68) {
                revert(
                    "GenericAdapter: contract call failed without revert reason"
                );
            }
            // Return the call's revert reason.
            assembly {
                let ptr := mload(0x40)
                let size := returndatasize
                returndatacopy(ptr, 0, size)
                revert(ptr, size)
            }
        }
    }
}

pragma solidity ^0.5.17;

import "../Governance/Claimable.sol";

contract Claimer {
    Claimable child;

    constructor(Claimable _child) public {
        child = _child;
    }

    function transferStoreOwnership(address _newOwner) external {
        child.transferOwnership(_newOwner);
    }

    function claimStoreOwnership() external {
        child.claimOwnership();
    }

    function claimTokenOwnership() public {
        child.claimOwnership();
    }

    function transferTokenOwnership(address _newOwner) public {
        child.transferOwnership(address(_newOwner));
    }
}

pragma solidity ^0.5.17;

import {String} from "../libraries/String.sol";

/// @dev StringTest exposes the internal functions of String.sol.
contract StringTest {
    function fromUint(uint256 _i) public pure returns (string memory) {
        return String.fromUint(_i);
    }

    function fromBytes32(bytes32 _value) public pure returns (string memory) {
        return String.fromBytes32(_value);
    }

    function fromAddress(address _addr) public pure returns (string memory) {
        return String.fromAddress(_addr);
    }

    function add4(
        string memory a,
        string memory b,
        string memory c,
        string memory d
    ) public pure returns (string memory) {
        return String.add8(a, b, c, d, "", "", "", "");
    }
}

pragma solidity ^0.5.17;

import "../libraries/LinkedList.sol";

/// @notice A token that exposes the LinkedList library for testing.
contract LinkedListTest {
    using LinkedList for LinkedList.List;

    LinkedList.List private ll;

    function isInList(address node) public view returns (bool) {
        return ll.isInList(node);
    }

    function next(address node) public view returns (address) {
        return ll.next(node);
    }

    function previous(address node) public view returns (address) {
        return ll.previous(node);
    }

    function begin() public view returns (address) {
        return ll.begin();
    }

    function end() public view returns (address) {
        return ll.end();
    }

    function insertBefore(address target, address newNode) public {
        ll.insertBefore(target, newNode);
    }

    function insertAfter(address target, address newNode) public {
        ll.insertAfter(target, newNode);
    }

    function remove(address node) public {
        ll.remove(node);
    }

    function prepend(address newNode) public {
        ll.prepend(newNode);
    }

    function append(address newNode) public {
        ll.append(newNode);
    }

    function swap(address node1, address node2) public {
        ll.swap(node1, node2);
    }

    function elements(address _start, uint256 _count)
        public
        view
        returns (address[] memory)
    {
        return ll.elements(_start, _count);
    }
}

pragma solidity ^0.5.17;

contract Migrations {
    address public owner;
    uint256 public last_completed_migration;

    modifier restricted() {
        if (msg.sender == owner) {
            _;
        }
    }

    constructor() public {
        owner = msg.sender;
    }

    function setCompleted(uint256 completed) public restricted {
        last_completed_migration = completed;
    }

    function upgrade(address new_address) public restricted {
        Migrations upgraded = Migrations(new_address);
        upgraded.setCompleted(last_completed_migration);
    }
}

pragma solidity ^0.5.17;

contract ForceSend {
    function send(address payable recipient) public payable {
        selfdestruct(recipient);
    }
}

{
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "abi"
      ]
    }
  },
  "libraries": {}
}

• No Contract Security Audit Submitted- Submit Audit Here

[{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"previousAdmin","type":"address"},{"indexed":false,"internalType":"address","name":"newAdmin","type":"address"}],"name":"AdminChanged","type":"event"},{"anonymous":false,"inputs":[{"indexed":true,"internalType":"address","name":"implementation","type":"address"}],"name":"Upgraded","type":"event"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"constant":false,"inputs":[],"name":"admin","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"newAdmin","type":"address"}],"name":"changeAdmin","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"implementation","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"_logic","type":"address"},{"internalType":"address","name":"_admin","type":"address"},{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"initialize","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"_logic","type":"address"},{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"initialize","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"newImplementation","type":"address"}],"name":"upgradeTo","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"newImplementation","type":"address"},{"internalType":"bytes","name":"data","type":"bytes"}],"name":"upgradeToAndCall","outputs":[],"payable":true,"stateMutability":"payable","type":"function"}]

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