// File: @openzeppelin/contracts/GSN/Context.sol
// SPDX-License-Identifier: MIT
pragma solidity >=0.6.0 <0.8.0;

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

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

pragma solidity >=0.6.0 <0.8.0;

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

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

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

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

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

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

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
  /**
   * @dev Returns the addition of two unsigned integers, reverting on
   * overflow.
   *
   * Counterpart to Solidity's `+` operator.
   *
   * Requirements:
   *
   * - Addition cannot overflow.
   */
  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    require(c >= a, "SafeMath: addition overflow");
    return c;
  }

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

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

  /**
   * @dev Returns the multiplication of two unsigned integers, reverting on
   * overflow.
   *
   * Counterpart to Solidity's `*` operator.
   *
   * Requirements:
   *
   * - Multiplication cannot overflow.
   */
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
    if (a == 0) {
      return 0;
    }
    uint256 c = a * b;
    require(c / a == b, "SafeMath: multiplication overflow");
    return c;
  }

  /**
   * @dev Returns the integer division of two unsigned integers. Reverts on
   * division by zero. The result is rounded towards zero.
   *
   * Counterpart to Solidity's `/` operator. Note: this function uses a
   * `revert` opcode (which leaves remaining gas untouched) while Solidity
   * uses an invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   *
   * - The divisor cannot be zero.
   */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    return div(a, b, "SafeMath: division by zero");
  }

  /**
   * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
   * division by zero. The result is rounded towards zero.
   *
   * Counterpart to Solidity's `/` operator. Note: this function uses a
   * `revert` opcode (which leaves remaining gas untouched) while Solidity
   * uses an invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   *
   * - The divisor cannot be zero.
   */
  function div(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b > 0, errorMessage);
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold
    return c;
  }

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

  /**
   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
   * Reverts with custom message when dividing by zero.
   *
   * Counterpart to Solidity's `%` operator. This function uses a `revert`
   * opcode (which leaves remaining gas untouched) while Solidity uses an
   * invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   *
   * - The divisor cannot be zero.
   */
  function mod(
    uint256 a,
    uint256 b,
    string memory errorMessage
  ) internal pure returns (uint256) {
    require(b != 0, errorMessage);
    return a % b;
  }
}
// File: @openzeppelin/contracts/token/ERC20/IERC20.sol

pragma solidity >=0.6.0 <0.8.0;

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

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

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

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

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

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

  /**
   * @dev Emitted when `value` tokens are moved from one account (`from`) to
   * another (`to`).
   *
   * Note that `value` may be zero.
   */
  event Transfer(address indexed from, address indexed to, uint256 value);
  /**
   * @dev Emitted when the allowance of a `spender` for an `owner` is set by
   * a call to {approve}. `value` is the new allowance.
   */
  event Approval(address indexed owner, address indexed spender, uint256 value);
}
// File: @openzeppelin/contracts/utils/Address.sol

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
  /**
   * @dev Returns true if `account` is a contract.
   *
   * [IMPORTANT]
   * ====
   * It is unsafe to assume that an address for which this function returns
   * false is an externally-owned account (EOA) and not a contract.
   *
   * Among others, `isContract` will return false for the following
   * types of addresses:
   *
   *  - an externally-owned account
   *  - a contract in construction
   *  - an address where a contract will be created
   *  - an address where a contract lived, but was destroyed
   * ====
   */
  function isContract(address account) internal view returns (bool) {
    // This method relies on extcodesize, which returns 0 for contracts in
    // construction, since the code is only stored at the end of the
    // constructor execution.
    uint256 size;
    // solhint-disable-next-line no-inline-assembly
    assembly {
      size := extcodesize(account)
    }
    return size > 0;
  }

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

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

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

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

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

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

  /**
   * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
   * but performing a static call.
   *
   * _Available since v3.3._
   */
  function functionStaticCall(
    address target,
    bytes memory data,
    string memory errorMessage
  ) internal view returns (bytes memory) {
    require(isContract(target), "Address: static call to non-contract");
    // solhint-disable-next-line avoid-low-level-calls
    (bool success, bytes memory returndata) = target.staticcall(data);
    return _verifyCallResult(success, returndata, errorMessage);
  }

  function _verifyCallResult(
    bool success,
    bytes memory returndata,
    string memory errorMessage
  ) private pure returns (bytes memory) {
    if (success) {
      return returndata;
    } else {
      // Look for revert reason and bubble it up if present
      if (returndata.length > 0) {
        // The easiest way to bubble the revert reason is using memory via assembly
        // solhint-disable-next-line no-inline-assembly
        assembly {
          let returndata_size := mload(returndata)
          revert(add(32, returndata), returndata_size)
        }
      } else {
        revert(errorMessage);
      }
    }
  }
}
// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol

pragma solidity >=0.6.0 <0.8.0;

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

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

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

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

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

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

  /**
   * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
   * on the return value: the return value is optional (but if data is returned, it must not be false).
   * @param token The token targeted by the call.
   * @param data The call data (encoded using abi.encode or one of its variants).
   */
  function _callOptionalReturn(IERC20 token, bytes memory data) private {
    // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
    // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
    // the target address contains contract code and also asserts for success in the low-level call.
    bytes memory returndata =
      address(token).functionCall(data, "SafeERC20: low-level call failed");
    if (returndata.length > 0) {
      // Return data is optional
      // solhint-disable-next-line max-line-length
      require(
        abi.decode(returndata, (bool)),
        "SafeERC20: ERC20 operation did not succeed"
      );
    }
  }
}

// File: contracts/interfaces/ILight.sol
/*
  Copyright 2021 Swap Holdings Ltd.
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/
interface ILight {
  event Swap(
    uint256 indexed nonce,
    uint256 timestamp,
    address indexed signerWallet,
    IERC20 signerToken,
    uint256 signerAmount,
    uint256 signerFee,
    address indexed senderWallet,
    IERC20 senderToken,
    uint256 senderAmount
  );
  event Cancel(uint256 indexed nonce, address indexed signerWallet);
  event Authorize(address indexed signer, address indexed signerWallet);
  event Revoke(address indexed signer, address indexed signerWallet);

  function swapWithRecipient(
    address recipient,
    uint256 nonce,
    uint256 expiry,
    address signerWallet,
    IERC20 signerToken,
    uint256 signerAmount,
    IERC20 senderToken,
    uint256 senderAmount,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;

  function swap(
    uint256 nonce,
    uint256 expiry,
    address signerWallet,
    IERC20 signerToken,
    uint256 signerAmount,
    IERC20 senderToken,
    uint256 senderAmount,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;

  function authorize(address sender) external;

  function revoke() external;

  function cancel(uint256[] calldata nonces) external;

  function nonceUsed(address, uint256) external view returns (bool);

  function authorized(address) external view returns (address);
}

// File: contracts/Light.sol
/*
  Copyright 2021 Swap Holdings Ltd.
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at
    http://www.apache.org/licenses/LICENSE-2.0
  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
*/
/* solhint-disable var-name-mixedcase */
/**
 * @title Light: Simple atomic swap
 * @notice https://www.airswap.io/
 */
contract Light is ILight, Ownable {
  using SafeERC20 for IERC20;
  using SafeMath for uint256;
  bytes32 public constant DOMAIN_TYPEHASH =
    keccak256(
      abi.encodePacked(
        "EIP712Domain(",
        "string name,",
        "string version,",
        "uint256 chainId,",
        "address verifyingContract",
        ")"
      )
    );
  bytes32 public constant ORDER_TYPEHASH =
    keccak256(
      abi.encodePacked(
        "LightOrder(",
        "uint256 nonce,",
        "uint256 expiry,",
        "address signerWallet,",
        "address signerToken,",
        "uint256 signerAmount,",
        "uint256 signerFee,",
        "address senderWallet,",
        "address senderToken,",
        "uint256 senderAmount",
        ")"
      )
    );
  bytes32 public constant DOMAIN_NAME = keccak256("SWAP_LIGHT");
  bytes32 public constant DOMAIN_VERSION = keccak256("3");
  uint256 public immutable DOMAIN_CHAIN_ID;
  bytes32 public immutable DOMAIN_SEPARATOR;
  uint256 public constant FEE_DIVISOR = 10000;
  uint256 public signerFee;
  /**
   * @notice Double mapping of signers to nonce groups to nonce states
   * @dev The nonce group is computed as nonce / 256, so each group of 256 sequential nonces uses the same key
   * @dev The nonce states are encoded as 256 bits, for each nonce in the group 0 means available and 1 means used
   */
  mapping(address => mapping(uint256 => uint256)) internal _nonceGroups;
  mapping(address => address) public override authorized;
  address public feeWallet;

  constructor(address _feeWallet, uint256 _fee) public {
    // Ensure the fee wallet is not null
    require(_feeWallet != address(0), "INVALID_FEE_WALLET");
    // Ensure the fee is less than divisor
    require(_fee < FEE_DIVISOR, "INVALID_FEE");
    uint256 currentChainId = getChainId();
    DOMAIN_CHAIN_ID = currentChainId;
    DOMAIN_SEPARATOR = keccak256(
      abi.encode(
        DOMAIN_TYPEHASH,
        DOMAIN_NAME,
        DOMAIN_VERSION,
        currentChainId,
        this
      )
    );
    feeWallet = _feeWallet;
    signerFee = _fee;
  }

  /**
   * @notice Atomic Token Swap
   * @param nonce uint256 Unique and should be sequential
   * @param expiry uint256 Expiry in seconds since 1 January 1970
   * @param signerWallet address Wallet of the signer
   * @param signerToken address ERC20 token transferred from the signer
   * @param signerAmount uint256 Amount transferred from the signer
   * @param senderToken address ERC20 token transferred from the sender
   * @param senderAmount uint256 Amount transferred from the sender
   * @param v uint8 "v" value of the ECDSA signature
   * @param r bytes32 "r" value of the ECDSA signature
   * @param s bytes32 "s" value of the ECDSA signature
   */
  function swap(
    uint256 nonce,
    uint256 expiry,
    address signerWallet,
    IERC20 signerToken,
    uint256 signerAmount,
    IERC20 senderToken,
    uint256 senderAmount,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external override {
    swapWithRecipient(
      msg.sender,
      nonce,
      expiry,
      signerWallet,
      signerToken,
      signerAmount,
      senderToken,
      senderAmount,
      v,
      r,
      s
    );
  }

  /**
   * @notice Atomic Token Swap with Recipient
   * @param recipient Wallet of the recipient
   * @param nonce uint256 Unique and should be sequential
   * @param expiry uint256 Expiry in seconds since 1 January 1970
   * @param signerWallet address Wallet of the signer
   * @param signerToken address ERC20 token transferred from the signer
   * @param signerAmount uint256 Amount transferred from the signer
   * @param senderToken address ERC20 token transferred from the sender
   * @param senderAmount uint256 Amount transferred from the sender
   * @param v uint8 "v" value of the ECDSA signature
   * @param r bytes32 "r" value of the ECDSA signature
   * @param s bytes32 "s" value of the ECDSA signature
   */
  function swapWithRecipient(
    address recipient,
    uint256 nonce,
    uint256 expiry,
    address signerWallet,
    IERC20 signerToken,
    uint256 signerAmount,
    IERC20 senderToken,
    uint256 senderAmount,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) public override {
    require(DOMAIN_CHAIN_ID == getChainId(), "CHAIN_ID_CHANGED");
    // Ensure the expiry is not passed
    require(expiry > block.timestamp, "EXPIRY_PASSED");
    bytes32 hashed =
      _getOrderHash(
        nonce,
        expiry,
        signerWallet,
        signerToken,
        signerAmount,
        msg.sender,
        senderToken,
        senderAmount
      );
    // Recover the signatory from the hash and signature
    address signatory = _getSignatory(hashed, v, r, s);
    // Ensure the nonce is not yet used and if not mark it used
    require(_markNonceAsUsed(signatory, nonce), "NONCE_ALREADY_USED");
    // Ensure the signatory is authorized by the signer wallet
    if (signerWallet != signatory) {
      require(authorized[signerWallet] == signatory, "UNAUTHORIZED");
    }
    // Transfer token from sender to signer
    senderToken.safeTransferFrom(msg.sender, signerWallet, senderAmount);
    // Transfer token from signer to recipient
    signerToken.safeTransferFrom(signerWallet, recipient, signerAmount);
    // Transfer fee from signer to feeWallet
    uint256 feeAmount = signerAmount.mul(signerFee).div(FEE_DIVISOR);
    if (feeAmount > 0) {
      signerToken.safeTransferFrom(signerWallet, feeWallet, feeAmount);
    }
    // Emit a Swap event
    emit Swap(
      nonce,
      block.timestamp,
      signerWallet,
      signerToken,
      signerAmount,
      signerFee,
      msg.sender,
      senderToken,
      senderAmount
    );
  }

  /**
   * @notice Set the fee wallet
   * @param newFeeWallet address Wallet to transfer signerFee to
   */
  function setFeeWallet(address newFeeWallet) external onlyOwner {
    // Ensure the new fee wallet is not null
    require(newFeeWallet != address(0), "INVALID_FEE_WALLET");
    feeWallet = newFeeWallet;
  }

  /**
   * @notice Set the fee
   * @param newSignerFee uint256 Value of the fee in basis points
   */
  function setFee(uint256 newSignerFee) external onlyOwner {
    // Ensure the fee is less than divisor
    require(newSignerFee < FEE_DIVISOR, "INVALID_FEE");
    signerFee = newSignerFee;
  }

  /**
   * @notice Authorize a signer
   * @param signer address Wallet of the signer to authorize
   * @dev Emits an Authorize event
   */
  function authorize(address signer) external override {
    authorized[msg.sender] = signer;
    emit Authorize(signer, msg.sender);
  }

  /**
   * @notice Revoke authorization of a signer
   * @dev Emits a Revoke event
   */
  function revoke() external override {
    address tmp = authorized[msg.sender];
    delete authorized[msg.sender];
    emit Revoke(tmp, msg.sender);
  }

  /**
   * @notice Cancel one or more nonces
   * @dev Cancelled nonces are marked as used
   * @dev Emits a Cancel event
   * @dev Out of gas may occur in arrays of length > 400
   * @param nonces uint256[] List of nonces to cancel
   */
  function cancel(uint256[] calldata nonces) external override {
    for (uint256 i = 0; i < nonces.length; i++) {
      uint256 nonce = nonces[i];
      if (_markNonceAsUsed(msg.sender, nonce)) {
        emit Cancel(nonce, msg.sender);
      }
    }
  }

  /**
   * @notice Returns true if the nonce has been used
   * @param signer address Address of the signer
   * @param nonce uint256 Nonce being checked
   */
  function nonceUsed(address signer, uint256 nonce)
    public
    view
    override
    returns (bool)
  {
    uint256 groupKey = nonce / 256;
    uint256 indexInGroup = nonce % 256;
    return (_nonceGroups[signer][groupKey] >> indexInGroup) & 1 == 1;
  }

  /**
   * @notice Returns the current chainId using the chainid opcode
   * @return id uint256 The chain id
   */
  function getChainId() public pure returns (uint256 id) {
    // no-inline-assembly
    assembly {
      id := chainid()
    }
  }

  /**
   * @notice Marks a nonce as used for the given signer
   * @param signer address Address of the signer for which to mark the nonce as used
   * @param nonce uint256 Nonce to be marked as used
   * @return bool True if the nonce was not marked as used already
   */
  function _markNonceAsUsed(address signer, uint256 nonce)
    internal
    returns (bool)
  {
    uint256 groupKey = nonce / 256;
    uint256 indexInGroup = nonce % 256;
    uint256 group = _nonceGroups[signer][groupKey];
    // If it is already used, return false
    if ((group >> indexInGroup) & 1 == 1) {
      return false;
    }
    _nonceGroups[signer][groupKey] = group | (uint256(1) << indexInGroup);
    return true;
  }

  /**
   * @notice Hash order parameters
   * @param nonce uint256
   * @param expiry uint256
   * @param signerWallet address
   * @param signerToken address
   * @param signerAmount uint256
   * @param senderToken address
   * @param senderAmount uint256
   * @return bytes32
   */
  function _getOrderHash(
    uint256 nonce,
    uint256 expiry,
    address signerWallet,
    IERC20 signerToken,
    uint256 signerAmount,
    address senderWallet,
    IERC20 senderToken,
    uint256 senderAmount
  ) internal view returns (bytes32) {
    return
      keccak256(
        abi.encode(
          ORDER_TYPEHASH,
          nonce,
          expiry,
          signerWallet,
          signerToken,
          signerAmount,
          signerFee,
          senderWallet,
          senderToken,
          senderAmount
        )
      );
  }

  /**
   * @notice Recover the signatory from a signature
   * @param hash bytes32
   * @param v uint8
   * @param r bytes32
   * @param s bytes32
   */
  function _getSignatory(
    bytes32 hash,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) internal view returns (address) {
    bytes32 digest =
      keccak256(abi.encodePacked("\x19\x01", DOMAIN_SEPARATOR, hash));
    address signatory = ecrecover(digest, v, r, s);
    // Ensure the signatory is not null
    require(signatory != address(0), "INVALID_SIG");
    return signatory;
  }
}

// File: contracts/Imports.sol
// import "@gnosis.pm/mock-contract/contracts/MockContract.sol";
contract Imports {

}