// File: Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.2;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies in 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");
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
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: ECDSA.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

// A copy from https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2237/files

/**
 * @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.
   *
   * 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: invalid signature length");
    }

    // 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 := mload(add(signature, 0x41))
    }

    return recover(hash, v, r, s);
  }

  /**
   * @dev Overload of {ECDSA-recover-bytes32-bytes-} that receives the `v`,
   * `r` and `s` signature fields separately.
   */
  function recover(
    bytes32 hash,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) internal pure returns (address) {
    // 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.
    require(uint256(s) <= 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0, "ECDSA: invalid signature 's' value");
    require(v == 27 || v == 28, "ECDSA: invalid signature 'v' value");

    // If the signature is valid (and not malleable), return the signer address
    address signer = ecrecover(hash, v, r, s);
    require(signer != address(0), "ECDSA: invalid signature");

    return signer;
  }

  /**
   * @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));
  }
}

// File: ENS.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

interface ENS {
  function resolver(bytes32 node) external view returns (Resolver);
}

interface Resolver {
  function addr(bytes32 node) external view returns (address);
}

contract EnsResolve {
  function resolve(bytes32 node) public view virtual returns (address) {
    ENS Registry = ENS(
      getChainId() == 1 ? 0x00000000000C2E074eC69A0dFb2997BA6C7d2e1e : 0x8595bFb0D940DfEDC98943FA8a907091203f25EE
    );
    return Registry.resolver(node).addr(node);
  }

  function bulkResolve(bytes32[] memory domains) public view returns (address[] memory result) {
    result = new address[](domains.length);
    for (uint256 i = 0; i < domains.length; i++) {
      result[i] = resolve(domains[i]);
    }
  }

  function getChainId() internal pure returns (uint256) {
    uint256 chainId;
    assembly {
      chainId := chainid()
    }
    return chainId;
  }
}

// File: ENSNamehash.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/*
 * @dev Solidity implementation of the ENS namehash algorithm.
 *
 * Warning! Does not normalize or validate names before hashing.
 * Original version can be found here https://github.com/JonahGroendal/ens-namehash/
 */
library ENSNamehash {
  function namehash(bytes memory domain) internal pure returns (bytes32) {
    return namehash(domain, 0);
  }

  function namehash(bytes memory domain, uint256 i) internal pure returns (bytes32) {
    if (domain.length <= i) return 0x0000000000000000000000000000000000000000000000000000000000000000;

    uint256 len = labelLength(domain, i);

    return keccak256(abi.encodePacked(namehash(domain, i + len + 1), keccak(domain, i, len)));
  }

  function labelLength(bytes memory domain, uint256 i) private pure returns (uint256) {
    uint256 len;
    while (i + len != domain.length && domain[i + len] != 0x2e) {
      len++;
    }
    return len;
  }

  function keccak(
    bytes memory data,
    uint256 offset,
    uint256 len
  ) private pure returns (bytes32 ret) {
    require(offset + len <= data.length);
    assembly {
      ret := keccak256(add(add(data, 32), offset), len)
    }
  }
}

// File: ERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import "./Context.sol";
import "./IERC20.sol";
import "./SafeMath.sol";
import "./Address.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20 {
    using SafeMath for uint256;
    using Address for address;

    mapping (address => uint256) private _balances;

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

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;

    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory name, string memory symbol) public {
        _name = name;
        _symbol = symbol;
        _decimals = 18;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view returns (string memory) {
        return _name;
    }

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

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5,05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view returns (uint8) {
        return _decimals;
    }

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

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

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

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

    /**
     * @dev See {IERC20-approve}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for ``sender``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(addedValue));
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements
     *
     * - `to` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

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

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

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

    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal {
        _decimals = decimals_;
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

// File: ERC20Burnable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import "./Context.sol";
import "./ERC20.sol";

/**
 * @dev Extension of {ERC20} that allows token holders to destroy both their own
 * tokens and those that they have an allowance for, in a way that can be
 * recognized off-chain (via event analysis).
 */
abstract contract ERC20Burnable is Context, ERC20 {
    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for ``accounts``'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual {
        uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");

        _approve(account, _msgSender(), decreasedAllowance);
        _burn(account, amount);
    }
}

// File: ERC20Permit.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

// Adapted copy from https://github.com/OpenZeppelin/openzeppelin-contracts/pull/2237/files

import "./ERC20.sol";
import "./ECDSA.sol";

/**
 * @dev Extension of {ERC20} that allows token holders to use their tokens
 * without sending any transactions by setting {IERC20-allowance} with a
 * signature using the {permit} method, and then spend them via
 * {IERC20-transferFrom}.
 *
 * The {permit} signature mechanism conforms to the {IERC2612Permit} interface.
 */
abstract contract ERC20Permit is ERC20 {
  mapping(address => uint256) private _nonces;

  bytes32 private constant _PERMIT_TYPEHASH = keccak256(
    "Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)"
  );

  // Mapping of ChainID to domain separators. This is a very gas efficient way
  // to not recalculate the domain separator on every call, while still
  // automatically detecting ChainID changes.
  mapping(uint256 => bytes32) private _domainSeparators;

  constructor() internal {
    _updateDomainSeparator();
  }

  /**
   * @dev See {IERC2612Permit-permit}.
   *
   * If https://eips.ethereum.org/EIPS/eip-1344[ChainID] ever changes, the
   * EIP712 Domain Separator is automatically recalculated.
   */
  function permit(
    address owner,
    address spender,
    uint256 amount,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) public {
    require(blockTimestamp() <= deadline, "ERC20Permit: expired deadline");

    bytes32 hashStruct = keccak256(abi.encode(_PERMIT_TYPEHASH, owner, spender, amount, _nonces[owner], deadline));

    bytes32 hash = keccak256(abi.encodePacked(uint16(0x1901), _domainSeparator(), hashStruct));

    address signer = ECDSA.recover(hash, v, r, s);
    require(signer == owner, "ERC20Permit: invalid signature");

    _nonces[owner]++;
    _approve(owner, spender, amount);
  }

  /**
   * @dev See {IERC2612Permit-nonces}.
   */
  function nonces(address owner) public view returns (uint256) {
    return _nonces[owner];
  }

  function _updateDomainSeparator() private returns (bytes32) {
    uint256 _chainID = chainID();

    bytes32 newDomainSeparator = keccak256(
      abi.encode(
        keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
        keccak256(bytes(name())),
        keccak256(bytes("1")), // Version
        _chainID,
        address(this)
      )
    );

    _domainSeparators[_chainID] = newDomainSeparator;

    return newDomainSeparator;
  }

  // Returns the domain separator, updating it if chainID changes
  function _domainSeparator() private returns (bytes32) {
    bytes32 domainSeparator = _domainSeparators[chainID()];
    if (domainSeparator != 0x00) {
      return domainSeparator;
    } else {
      return _updateDomainSeparator();
    }
  }

  function chainID() public view virtual returns (uint256 _chainID) {
    assembly {
      _chainID := chainid()
    }
  }

  function blockTimestamp() public view virtual returns (uint256) {
    return block.timestamp;
  }
}

// File: FeeManager.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.12;
pragma experimental ABIEncoderV2;

import { UniswapV3OracleHelper } from "./UniswapV3OracleHelper.sol";
import { SafeMath } from "./SafeMath.sol";
import { EnsResolve } from "./ENS.sol";

import "./IERC20.sol";
import "./ITornadoInstance.sol";
import "./InstanceRegistry.sol";

/// @dev contract which calculates the fee for each pool
contract FeeManager is EnsResolve {
  using SafeMath for uint256;

  uint256 public constant PROTOCOL_FEE_DIVIDER = 10000;
  address public immutable torn;
  address public immutable governance;
  InstanceRegistry public immutable registry;

  uint24 public uniswapTornPoolSwappingFee;
  uint32 public uniswapTimePeriod;

  uint24 public updateFeeTimeLimit;

  mapping(ITornadoInstance => uint160) public instanceFee;
  mapping(ITornadoInstance => uint256) public instanceFeeUpdated;

  event FeeUpdated(address indexed instance, uint256 newFee);
  event UniswapTornPoolSwappingFeeChanged(uint24 newFee);

  modifier onlyGovernance() {
    require(msg.sender == governance);
    _;
  }

  struct Deviation {
    address instance;
    int256 deviation; // in 10**-1 percents, so it can be like -2.3% if the price of TORN declined
  }

  constructor(
    address _torn,
    address _governance,
    bytes32 _registry
  ) public {
    torn = _torn;
    governance = _governance;
    registry = InstanceRegistry(resolve(_registry));
  }

  /**
   * @notice This function should update the fees of each pool
   */
  function updateAllFees() external {
    updateFees(registry.getAllInstanceAddresses());
  }

  /**
   * @notice This function should update the fees for tornado instances
   *         (here called pools)
   * @param _instances pool addresses to update fees for
   * */
  function updateFees(ITornadoInstance[] memory _instances) public {
    for (uint256 i = 0; i < _instances.length; i++) {
      updateFee(_instances[i]);
    }
  }

  /**
   * @notice This function should update the fee of a specific pool
   * @param _instance address of the pool to update fees for
   */
  function updateFee(ITornadoInstance _instance) public {
    uint160 newFee = calculatePoolFee(_instance);
    instanceFee[_instance] = newFee;
    instanceFeeUpdated[_instance] = now;
    emit FeeUpdated(address(_instance), newFee);
  }

  /**
   * @notice This function should return the fee of a specific pool and update it if the time has come
   * @param _instance address of the pool to get fees for
   */
  function instanceFeeWithUpdate(ITornadoInstance _instance) public returns (uint160) {
    if (now - instanceFeeUpdated[_instance] > updateFeeTimeLimit) {
      updateFee(_instance);
    }
    return instanceFee[_instance];
  }

  /**
   * @notice function to update a single fee entry
   * @param _instance instance for which to update data
   * @return newFee the new fee pool
   */
  function calculatePoolFee(ITornadoInstance _instance) public view returns (uint160) {
    (bool isERC20, IERC20 token, , uint24 uniswapPoolSwappingFee, uint32 protocolFeePercentage) = registry.instances(_instance);
    if (protocolFeePercentage == 0) {
      return 0;
    }

    token = token == IERC20(0) && !isERC20 ? IERC20(UniswapV3OracleHelper.WETH) : token; // for eth instances
    uint256 tokenPriceRatio = UniswapV3OracleHelper.getPriceRatioOfTokens(
      [torn, address(token)],
      [uniswapTornPoolSwappingFee, uniswapPoolSwappingFee],
      uniswapTimePeriod
    );
    // prettier-ignore
    return
      uint160(
        _instance
        .denomination()
        .mul(UniswapV3OracleHelper.RATIO_DIVIDER)
        .div(tokenPriceRatio)
        .mul(uint256(protocolFeePercentage))
        .div(PROTOCOL_FEE_DIVIDER)
      );
  }

  /**
   * @notice function to update the uniswap fee
   * @param _uniswapTornPoolSwappingFee new uniswap fee
   */
  function setUniswapTornPoolSwappingFee(uint24 _uniswapTornPoolSwappingFee) public onlyGovernance {
    uniswapTornPoolSwappingFee = _uniswapTornPoolSwappingFee;
    emit UniswapTornPoolSwappingFeeChanged(uniswapTornPoolSwappingFee);
  }

  /**
   * @notice This function should allow governance to set a new period for twap measurement
   * @param newPeriod the new period to use
   * */
  function setPeriodForTWAPOracle(uint32 newPeriod) external onlyGovernance {
    uniswapTimePeriod = newPeriod;
  }

  /**
   * @notice This function should allow governance to set a new update fee time limit for instance fee updating
   * @param newLimit the new time limit to use
   * */
  function setUpdateFeeTimeLimit(uint24 newLimit) external onlyGovernance {
    updateFeeTimeLimit = newLimit;
  }

  /**
   * @notice returns fees deviations for each instance, so it can be easily seen what instance requires an update
   */
  function feeDeviations() public view returns (Deviation[] memory results) {
    ITornadoInstance[] memory instances = registry.getAllInstanceAddresses();
    results = new Deviation[](instances.length);

    for (uint256 i = 0; i < instances.length; i++) {
      uint256 marketFee = calculatePoolFee(instances[i]);
      int256 deviation;
      if (marketFee != 0) {
        deviation = int256((instanceFee[instances[i]] * 1000) / marketFee) - 1000;
      }

      results[i] = Deviation({ instance: address(instances[i]), deviation: deviation });
    }
  }
}

// File: FullMath.sol



// SPDX-License-Identifier: MIT
pragma solidity >=0.4.0;

/// @title Contains 512-bit math functions
/// @notice Facilitates multiplication and division that can have overflow of an intermediate value without any loss of precision
/// @dev Handles "phantom overflow" i.e., allows multiplication and division where an intermediate value overflows 256 bits
library FullMath {
    /// @notice Calculates floor(a×b÷denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
    /// @param a The multiplicand
    /// @param b The multiplier
    /// @param denominator The divisor
    /// @return result The 256-bit result
    /// @dev Credit to Remco Bloemen under MIT license https://xn--2-umb.com/21/muldiv
    function mulDiv(
        uint256 a,
        uint256 b,
        uint256 denominator
    ) internal pure returns (uint256 result) {
        // 512-bit multiply [prod1 prod0] = a * b
        // Compute the product mod 2**256 and mod 2**256 - 1
        // then use the Chinese Remainder Theorem to reconstruct
        // the 512 bit result. The result is stored in two 256
        // variables such that product = prod1 * 2**256 + prod0
        uint256 prod0; // Least significant 256 bits of the product
        uint256 prod1; // Most significant 256 bits of the product
        assembly {
            let mm := mulmod(a, b, not(0))
            prod0 := mul(a, b)
            prod1 := sub(sub(mm, prod0), lt(mm, prod0))
        }

        // Handle non-overflow cases, 256 by 256 division
        if (prod1 == 0) {
            require(denominator > 0);
            assembly {
                result := div(prod0, denominator)
            }
            return result;
        }

        // Make sure the result is less than 2**256.
        // Also prevents denominator == 0
        require(denominator > prod1);

        ///////////////////////////////////////////////
        // 512 by 256 division.
        ///////////////////////////////////////////////

        // Make division exact by subtracting the remainder from [prod1 prod0]
        // Compute remainder using mulmod
        uint256 remainder;
        assembly {
            remainder := mulmod(a, b, denominator)
        }
        // Subtract 256 bit number from 512 bit number
        assembly {
            prod1 := sub(prod1, gt(remainder, prod0))
            prod0 := sub(prod0, remainder)
        }

        // Factor powers of two out of denominator
        // Compute largest power of two divisor of denominator.
        // Always >= 1.
        uint256 twos = (type(uint256).max - denominator + 1) & denominator;
        // Divide denominator by power of two
        assembly {
            denominator := div(denominator, twos)
        }

        // Divide [prod1 prod0] by the factors of two
        assembly {
            prod0 := div(prod0, twos)
        }
        // Shift in bits from prod1 into prod0. For this we need
        // to flip `twos` such that it is 2**256 / twos.
        // If twos is zero, then it becomes one
        assembly {
            twos := add(div(sub(0, twos), twos), 1)
        }
        prod0 |= prod1 * twos;

        // Invert denominator mod 2**256
        // Now that denominator is an odd number, it has an inverse
        // modulo 2**256 such that denominator * inv = 1 mod 2**256.
        // Compute the inverse by starting with a seed that is correct
        // correct for four bits. That is, denominator * inv = 1 mod 2**4
        uint256 inv = (3 * denominator) ^ 2;
        // Now use Newton-Raphson iteration to improve the precision.
        // Thanks to Hensel's lifting lemma, this also works in modular
        // arithmetic, doubling the correct bits in each step.
        inv *= 2 - denominator * inv; // inverse mod 2**8
        inv *= 2 - denominator * inv; // inverse mod 2**16
        inv *= 2 - denominator * inv; // inverse mod 2**32
        inv *= 2 - denominator * inv; // inverse mod 2**64
        inv *= 2 - denominator * inv; // inverse mod 2**128
        inv *= 2 - denominator * inv; // inverse mod 2**256

        // Because the division is now exact we can divide by multiplying
        // with the modular inverse of denominator. This will give us the
        // correct result modulo 2**256. Since the precoditions guarantee
        // that the outcome is less than 2**256, this is the final result.
        // We don't need to compute the high bits of the result and prod1
        // is no longer required.
        result = prod0 * inv;
        return result;
    }

    /// @notice Calculates ceil(a×b÷denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
    /// @param a The multiplicand
    /// @param b The multiplier
    /// @param denominator The divisor
    /// @return result The 256-bit result
    function mulDivRoundingUp(
        uint256 a,
        uint256 b,
        uint256 denominator
    ) internal pure returns (uint256 result) {
        result = mulDiv(a, b, denominator);
        if (mulmod(a, b, denominator) > 0) {
            require(result < type(uint256).max);
            result++;
        }
    }
}

// File: IENS.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.12;

interface IENS {
  function owner(bytes32 node) external view returns (address);
}

// File: IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

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

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

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

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

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

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

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: Initializable.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.4.24 <0.7.0;


/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 */
abstract 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 protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        require(_initializing || _isConstructor() || !_initialized, "Initializable: contract is already 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;
        // solhint-disable-next-line no-inline-assembly
        assembly { cs := extcodesize(self) }
        return cs == 0;
    }
}

// File: InstanceRegistry.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.12;
pragma experimental ABIEncoderV2;

import { Initializable } from "./Initializable.sol";
import { EnsResolve } from "./ENS.sol";
import "./IERC20.sol";
import "./SafeERC20.sol";
import "./ITornadoInstance.sol";
import "./FeeManager.sol";
import "./TornadoRouter.sol";

contract InstanceRegistry is Initializable, EnsResolve {
  using SafeERC20 for IERC20;

  enum InstanceState {
    DISABLED,
    ENABLED
  }

  struct Instance {
    bool isERC20;
    IERC20 token;
    InstanceState state;
    // the fee of the uniswap pool which will be used to get a TWAP
    uint24 uniswapPoolSwappingFee;
    // the fee the protocol takes from relayer, it should be multiplied by PROTOCOL_FEE_DIVIDER from FeeManager.sol
    uint32 protocolFeePercentage;
  }

  struct Tornado {
    ITornadoInstance addr;
    Instance instance;
  }

  address public immutable governance;
  TornadoRouter public router;

  mapping(ITornadoInstance => Instance) public instances;
  ITornadoInstance[] public instanceIds;

  event InstanceStateUpdated(ITornadoInstance indexed instance, InstanceState state);
  event RouterRegistered(address tornadoRouter);

  modifier onlyGovernance() {
    require(msg.sender == governance, "Not authorized");
    _;
  }

  constructor(address _governance) public {
    governance = _governance;
  }

  function initialize(Tornado[] memory _instances, bytes32 _router) external initializer {
    router = TornadoRouter(resolve(_router));
    for (uint256 i = 0; i < _instances.length; i++) {
      _updateInstance(_instances[i]);
      instanceIds.push(_instances[i].addr);
    }
  }

  /**
   * @dev Add or update an instance.
   */
  function updateInstance(Tornado calldata _tornado) external virtual onlyGovernance {
    require(_tornado.instance.state != InstanceState.DISABLED, "Use removeInstance() for remove");
    if (instances[_tornado.addr].state == InstanceState.DISABLED) {
      instanceIds.push(_tornado.addr);
    }
    _updateInstance(_tornado);
  }

  /**
   * @dev Remove an instance.
   * @param _instanceId The instance id in `instanceIds` mapping to remove.
   */
  function removeInstance(uint256 _instanceId) external virtual onlyGovernance {
    ITornadoInstance _instance = instanceIds[_instanceId];
    (bool isERC20, IERC20 token) = (instances[_instance].isERC20, instances[_instance].token);

    if (isERC20) {
      uint256 allowance = token.allowance(address(router), address(_instance));
      if (allowance != 0) {
        router.approveExactToken(token, address(_instance), 0);
      }
    }

    delete instances[_instance];
    instanceIds[_instanceId] = instanceIds[instanceIds.length - 1];
    instanceIds.pop();
    emit InstanceStateUpdated(_instance, InstanceState.DISABLED);
  }

  /**
   * @notice This function should allow governance to set a new protocol fee for relayers
   * @param instance the to update
   * @param newFee the new fee to use
   * */
  function setProtocolFee(ITornadoInstance instance, uint32 newFee) external onlyGovernance {
    instances[instance].protocolFeePercentage = newFee;
  }

  /**
   * @notice This function should allow governance to set a new tornado proxy address
   * @param routerAddress address of the new proxy
   * */
  function setTornadoRouter(address routerAddress) external onlyGovernance {
    router = TornadoRouter(routerAddress);
    emit RouterRegistered(routerAddress);
  }

  function _updateInstance(Tornado memory _tornado) internal virtual {
    instances[_tornado.addr] = _tornado.instance;
    if (_tornado.instance.isERC20) {
      IERC20 token = IERC20(_tornado.addr.token());
      require(token == _tornado.instance.token, "Incorrect token");
      uint256 allowance = token.allowance(address(router), address(_tornado.addr));

      if (allowance == 0) {
        router.approveExactToken(token, address(_tornado.addr), type(uint256).max);
      }
    }
    emit InstanceStateUpdated(_tornado.addr, _tornado.instance.state);
  }

  /**
   * @dev Returns all instance configs
   */
  function getAllInstances() public view returns (Tornado[] memory result) {
    result = new Tornado[](instanceIds.length);
    for (uint256 i = 0; i < instanceIds.length; i++) {
      ITornadoInstance _instance = instanceIds[i];
      result[i] = Tornado({ addr: _instance, instance: instances[_instance] });
    }
  }

  /**
   * @dev Returns all instance addresses
   */
  function getAllInstanceAddresses() public view returns (ITornadoInstance[] memory result) {
    result = new ITornadoInstance[](instanceIds.length);
    for (uint256 i = 0; i < instanceIds.length; i++) {
      result[i] = instanceIds[i];
    }
  }

  /// @notice get erc20 tornado instance token
  /// @param instance the interface (contract) key to the instance data
  function getPoolToken(ITornadoInstance instance) external view returns (address) {
    return address(instances[instance].token);
  }
}

// File: ITornadoGovernance.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.12;

import "./ITornadoVault.sol";

interface ITornadoGovernance {
  function lockedBalance(address account) external view returns (uint256);

  function userVault() external view returns (ITornadoVault);
}

// File: ITornadoInstance.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

interface ITornadoInstance {
  function token() external view returns (address);

  function denomination() external view returns (uint256);

  function deposit(bytes32 commitment) external payable;

  function withdraw(
    bytes calldata proof,
    bytes32 root,
    bytes32 nullifierHash,
    address payable recipient,
    address payable relayer,
    uint256 fee,
    uint256 refund
  ) external payable;
}

// File: ITornadoVault.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.12;
pragma experimental ABIEncoderV2;

interface ITornadoVault {
  function withdrawTorn(address recipient, uint256 amount) external;
}

// File: IUniswapV3Factory.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title The interface for the Uniswap V3 Factory
/// @notice The Uniswap V3 Factory facilitates creation of Uniswap V3 pools and control over the protocol fees
interface IUniswapV3Factory {
    /// @notice Emitted when the owner of the factory is changed
    /// @param oldOwner The owner before the owner was changed
    /// @param newOwner The owner after the owner was changed
    event OwnerChanged(address indexed oldOwner, address indexed newOwner);

    /// @notice Emitted when a pool is created
    /// @param token0 The first token of the pool by address sort order
    /// @param token1 The second token of the pool by address sort order
    /// @param fee The fee collected upon every swap in the pool, denominated in hundredths of a bip
    /// @param tickSpacing The minimum number of ticks between initialized ticks
    /// @param pool The address of the created pool
    event PoolCreated(
        address indexed token0,
        address indexed token1,
        uint24 indexed fee,
        int24 tickSpacing,
        address pool
    );

    /// @notice Emitted when a new fee amount is enabled for pool creation via the factory
    /// @param fee The enabled fee, denominated in hundredths of a bip
    /// @param tickSpacing The minimum number of ticks between initialized ticks for pools created with the given fee
    event FeeAmountEnabled(uint24 indexed fee, int24 indexed tickSpacing);

    /// @notice Returns the current owner of the factory
    /// @dev Can be changed by the current owner via setOwner
    /// @return The address of the factory owner
    function owner() external view returns (address);

    /// @notice Returns the tick spacing for a given fee amount, if enabled, or 0 if not enabled
    /// @dev A fee amount can never be removed, so this value should be hard coded or cached in the calling context
    /// @param fee The enabled fee, denominated in hundredths of a bip. Returns 0 in case of unenabled fee
    /// @return The tick spacing
    function feeAmountTickSpacing(uint24 fee) external view returns (int24);

    /// @notice Returns the pool address for a given pair of tokens and a fee, or address 0 if it does not exist
    /// @dev tokenA and tokenB may be passed in either token0/token1 or token1/token0 order
    /// @param tokenA The contract address of either token0 or token1
    /// @param tokenB The contract address of the other token
    /// @param fee The fee collected upon every swap in the pool, denominated in hundredths of a bip
    /// @return pool The pool address
    function getPool(
        address tokenA,
        address tokenB,
        uint24 fee
    ) external view returns (address pool);

    /// @notice Creates a pool for the given two tokens and fee
    /// @param tokenA One of the two tokens in the desired pool
    /// @param tokenB The other of the two tokens in the desired pool
    /// @param fee The desired fee for the pool
    /// @dev tokenA and tokenB may be passed in either order: token0/token1 or token1/token0. tickSpacing is retrieved
    /// from the fee. The call will revert if the pool already exists, the fee is invalid, or the token arguments
    /// are invalid.
    /// @return pool The address of the newly created pool
    function createPool(
        address tokenA,
        address tokenB,
        uint24 fee
    ) external returns (address pool);

    /// @notice Updates the owner of the factory
    /// @dev Must be called by the current owner
    /// @param _owner The new owner of the factory
    function setOwner(address _owner) external;

    /// @notice Enables a fee amount with the given tickSpacing
    /// @dev Fee amounts may never be removed once enabled
    /// @param fee The fee amount to enable, denominated in hundredths of a bip (i.e. 1e-6)
    /// @param tickSpacing The spacing between ticks to be enforced for all pools created with the given fee amount
    function enableFeeAmount(uint24 fee, int24 tickSpacing) external;
}

// File: IUniswapV3Pool.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

import './IUniswapV3PoolImmutables.sol';
import './IUniswapV3PoolState.sol';
import './IUniswapV3PoolDerivedState.sol';
import './IUniswapV3PoolActions.sol';
import './IUniswapV3PoolOwnerActions.sol';
import './IUniswapV3PoolEvents.sol';

/// @title The interface for a Uniswap V3 Pool
/// @notice A Uniswap pool facilitates swapping and automated market making between any two assets that strictly conform
/// to the ERC20 specification
/// @dev The pool interface is broken up into many smaller pieces
interface IUniswapV3Pool is
    IUniswapV3PoolImmutables,
    IUniswapV3PoolState,
    IUniswapV3PoolDerivedState,
    IUniswapV3PoolActions,
    IUniswapV3PoolOwnerActions,
    IUniswapV3PoolEvents
{

}

// File: IUniswapV3PoolActions.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Permissionless pool actions
/// @notice Contains pool methods that can be called by anyone
interface IUniswapV3PoolActions {
    /// @notice Sets the initial price for the pool
    /// @dev Price is represented as a sqrt(amountToken1/amountToken0) Q64.96 value
    /// @param sqrtPriceX96 the initial sqrt price of the pool as a Q64.96
    function initialize(uint160 sqrtPriceX96) external;

    /// @notice Adds liquidity for the given recipient/tickLower/tickUpper position
    /// @dev The caller of this method receives a callback in the form of IUniswapV3MintCallback#uniswapV3MintCallback
    /// in which they must pay any token0 or token1 owed for the liquidity. The amount of token0/token1 due depends
    /// on tickLower, tickUpper, the amount of liquidity, and the current price.
    /// @param recipient The address for which the liquidity will be created
    /// @param tickLower The lower tick of the position in which to add liquidity
    /// @param tickUpper The upper tick of the position in which to add liquidity
    /// @param amount The amount of liquidity to mint
    /// @param data Any data that should be passed through to the callback
    /// @return amount0 The amount of token0 that was paid to mint the given amount of liquidity. Matches the value in the callback
    /// @return amount1 The amount of token1 that was paid to mint the given amount of liquidity. Matches the value in the callback
    function mint(
        address recipient,
        int24 tickLower,
        int24 tickUpper,
        uint128 amount,
        bytes calldata data
    ) external returns (uint256 amount0, uint256 amount1);

    /// @notice Collects tokens owed to a position
    /// @dev Does not recompute fees earned, which must be done either via mint or burn of any amount of liquidity.
    /// Collect must be called by the position owner. To withdraw only token0 or only token1, amount0Requested or
    /// amount1Requested may be set to zero. To withdraw all tokens owed, caller may pass any value greater than the
    /// actual tokens owed, e.g. type(uint128).max. Tokens owed may be from accumulated swap fees or burned liquidity.
    /// @param recipient The address which should receive the fees collected
    /// @param tickLower The lower tick of the position for which to collect fees
    /// @param tickUpper The upper tick of the position for which to collect fees
    /// @param amount0Requested How much token0 should be withdrawn from the fees owed
    /// @param amount1Requested How much token1 should be withdrawn from the fees owed
    /// @return amount0 The amount of fees collected in token0
    /// @return amount1 The amount of fees collected in token1
    function collect(
        address recipient,
        int24 tickLower,
        int24 tickUpper,
        uint128 amount0Requested,
        uint128 amount1Requested
    ) external returns (uint128 amount0, uint128 amount1);

    /// @notice Burn liquidity from the sender and account tokens owed for the liquidity to the position
    /// @dev Can be used to trigger a recalculation of fees owed to a position by calling with an amount of 0
    /// @dev Fees must be collected separately via a call to #collect
    /// @param tickLower The lower tick of the position for which to burn liquidity
    /// @param tickUpper The upper tick of the position for which to burn liquidity
    /// @param amount How much liquidity to burn
    /// @return amount0 The amount of token0 sent to the recipient
    /// @return amount1 The amount of token1 sent to the recipient
    function burn(
        int24 tickLower,
        int24 tickUpper,
        uint128 amount
    ) external returns (uint256 amount0, uint256 amount1);

    /// @notice Swap token0 for token1, or token1 for token0
    /// @dev The caller of this method receives a callback in the form of IUniswapV3SwapCallback#uniswapV3SwapCallback
    /// @param recipient The address to receive the output of the swap
    /// @param zeroForOne The direction of the swap, true for token0 to token1, false for token1 to token0
    /// @param amountSpecified The amount of the swap, which implicitly configures the swap as exact input (positive), or exact output (negative)
    /// @param sqrtPriceLimitX96 The Q64.96 sqrt price limit. If zero for one, the price cannot be less than this
    /// value after the swap. If one for zero, the price cannot be greater than this value after the swap
    /// @param data Any data to be passed through to the callback
    /// @return amount0 The delta of the balance of token0 of the pool, exact when negative, minimum when positive
    /// @return amount1 The delta of the balance of token1 of the pool, exact when negative, minimum when positive
    function swap(
        address recipient,
        bool zeroForOne,
        int256 amountSpecified,
        uint160 sqrtPriceLimitX96,
        bytes calldata data
    ) external returns (int256 amount0, int256 amount1);

    /// @notice Receive token0 and/or token1 and pay it back, plus a fee, in the callback
    /// @dev The caller of this method receives a callback in the form of IUniswapV3FlashCallback#uniswapV3FlashCallback
    /// @dev Can be used to donate underlying tokens pro-rata to currently in-range liquidity providers by calling
    /// with 0 amount{0,1} and sending the donation amount(s) from the callback
    /// @param recipient The address which will receive the token0 and token1 amounts
    /// @param amount0 The amount of token0 to send
    /// @param amount1 The amount of token1 to send
    /// @param data Any data to be passed through to the callback
    function flash(
        address recipient,
        uint256 amount0,
        uint256 amount1,
        bytes calldata data
    ) external;

    /// @notice Increase the maximum number of price and liquidity observations that this pool will store
    /// @dev This method is no-op if the pool already has an observationCardinalityNext greater than or equal to
    /// the input observationCardinalityNext.
    /// @param observationCardinalityNext The desired minimum number of observations for the pool to store
    function increaseObservationCardinalityNext(uint16 observationCardinalityNext) external;
}

// File: IUniswapV3PoolDerivedState.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Pool state that is not stored
/// @notice Contains view functions to provide information about the pool that is computed rather than stored on the
/// blockchain. The functions here may have variable gas costs.
interface IUniswapV3PoolDerivedState {
    /// @notice Returns the cumulative tick and liquidity as of each timestamp `secondsAgo` from the current block timestamp
    /// @dev To get a time weighted average tick or liquidity-in-range, you must call this with two values, one representing
    /// the beginning of the period and another for the end of the period. E.g., to get the last hour time-weighted average tick,
    /// you must call it with secondsAgos = [3600, 0].
    /// @dev The time weighted average tick represents the geometric time weighted average price of the pool, in
    /// log base sqrt(1.0001) of token1 / token0. The TickMath library can be used to go from a tick value to a ratio.
    /// @param secondsAgos From how long ago each cumulative tick and liquidity value should be returned
    /// @return tickCumulatives Cumulative tick values as of each `secondsAgos` from the current block timestamp
    /// @return secondsPerLiquidityCumulativeX128s Cumulative seconds per liquidity-in-range value as of each `secondsAgos` from the current block
    /// timestamp
    function observe(uint32[] calldata secondsAgos)
        external
        view
        returns (int56[] memory tickCumulatives, uint160[] memory secondsPerLiquidityCumulativeX128s);

    /// @notice Returns a snapshot of the tick cumulative, seconds per liquidity and seconds inside a tick range
    /// @dev Snapshots must only be compared to other snapshots, taken over a period for which a position existed.
    /// I.e., snapshots cannot be compared if a position is not held for the entire period between when the first
    /// snapshot is taken and the second snapshot is taken.
    /// @param tickLower The lower tick of the range
    /// @param tickUpper The upper tick of the range
    /// @return tickCumulativeInside The snapshot of the tick accumulator for the range
    /// @return secondsPerLiquidityInsideX128 The snapshot of seconds per liquidity for the range
    /// @return secondsInside The snapshot of seconds per liquidity for the range
    function snapshotCumulativesInside(int24 tickLower, int24 tickUpper)
        external
        view
        returns (
            int56 tickCumulativeInside,
            uint160 secondsPerLiquidityInsideX128,
            uint32 secondsInside
        );
}

// File: IUniswapV3PoolEvents.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Events emitted by a pool
/// @notice Contains all events emitted by the pool
interface IUniswapV3PoolEvents {
    /// @notice Emitted exactly once by a pool when #initialize is first called on the pool
    /// @dev Mint/Burn/Swap cannot be emitted by the pool before Initialize
    /// @param sqrtPriceX96 The initial sqrt price of the pool, as a Q64.96
    /// @param tick The initial tick of the pool, i.e. log base 1.0001 of the starting price of the pool
    event Initialize(uint160 sqrtPriceX96, int24 tick);

    /// @notice Emitted when liquidity is minted for a given position
    /// @param sender The address that minted the liquidity
    /// @param owner The owner of the position and recipient of any minted liquidity
    /// @param tickLower The lower tick of the position
    /// @param tickUpper The upper tick of the position
    /// @param amount The amount of liquidity minted to the position range
    /// @param amount0 How much token0 was required for the minted liquidity
    /// @param amount1 How much token1 was required for the minted liquidity
    event Mint(
        address sender,
        address indexed owner,
        int24 indexed tickLower,
        int24 indexed tickUpper,
        uint128 amount,
        uint256 amount0,
        uint256 amount1
    );

    /// @notice Emitted when fees are collected by the owner of a position
    /// @dev Collect events may be emitted with zero amount0 and amount1 when the caller chooses not to collect fees
    /// @param owner The owner of the position for which fees are collected
    /// @param tickLower The lower tick of the position
    /// @param tickUpper The upper tick of the position
    /// @param amount0 The amount of token0 fees collected
    /// @param amount1 The amount of token1 fees collected
    event Collect(
        address indexed owner,
        address recipient,
        int24 indexed tickLower,
        int24 indexed tickUpper,
        uint128 amount0,
        uint128 amount1
    );

    /// @notice Emitted when a position's liquidity is removed
    /// @dev Does not withdraw any fees earned by the liquidity position, which must be withdrawn via #collect
    /// @param owner The owner of the position for which liquidity is removed
    /// @param tickLower The lower tick of the position
    /// @param tickUpper The upper tick of the position
    /// @param amount The amount of liquidity to remove
    /// @param amount0 The amount of token0 withdrawn
    /// @param amount1 The amount of token1 withdrawn
    event Burn(
        address indexed owner,
        int24 indexed tickLower,
        int24 indexed tickUpper,
        uint128 amount,
        uint256 amount0,
        uint256 amount1
    );

    /// @notice Emitted by the pool for any swaps between token0 and token1
    /// @param sender The address that initiated the swap call, and that received the callback
    /// @param recipient The address that received the output of the swap
    /// @param amount0 The delta of the token0 balance of the pool
    /// @param amount1 The delta of the token1 balance of the pool
    /// @param sqrtPriceX96 The sqrt(price) of the pool after the swap, as a Q64.96
    /// @param liquidity The liquidity of the pool after the swap
    /// @param tick The log base 1.0001 of price of the pool after the swap
    event Swap(
        address indexed sender,
        address indexed recipient,
        int256 amount0,
        int256 amount1,
        uint160 sqrtPriceX96,
        uint128 liquidity,
        int24 tick
    );

    /// @notice Emitted by the pool for any flashes of token0/token1
    /// @param sender The address that initiated the swap call, and that received the callback
    /// @param recipient The address that received the tokens from flash
    /// @param amount0 The amount of token0 that was flashed
    /// @param amount1 The amount of token1 that was flashed
    /// @param paid0 The amount of token0 paid for the flash, which can exceed the amount0 plus the fee
    /// @param paid1 The amount of token1 paid for the flash, which can exceed the amount1 plus the fee
    event Flash(
        address indexed sender,
        address indexed recipient,
        uint256 amount0,
        uint256 amount1,
        uint256 paid0,
        uint256 paid1
    );

    /// @notice Emitted by the pool for increases to the number of observations that can be stored
    /// @dev observationCardinalityNext is not the observation cardinality until an observation is written at the index
    /// just before a mint/swap/burn.
    /// @param observationCardinalityNextOld The previous value of the next observation cardinality
    /// @param observationCardinalityNextNew The updated value of the next observation cardinality
    event IncreaseObservationCardinalityNext(
        uint16 observationCardinalityNextOld,
        uint16 observationCardinalityNextNew
    );

    /// @notice Emitted when the protocol fee is changed by the pool
    /// @param feeProtocol0Old The previous value of the token0 protocol fee
    /// @param feeProtocol1Old The previous value of the token1 protocol fee
    /// @param feeProtocol0New The updated value of the token0 protocol fee
    /// @param feeProtocol1New The updated value of the token1 protocol fee
    event SetFeeProtocol(uint8 feeProtocol0Old, uint8 feeProtocol1Old, uint8 feeProtocol0New, uint8 feeProtocol1New);

    /// @notice Emitted when the collected protocol fees are withdrawn by the factory owner
    /// @param sender The address that collects the protocol fees
    /// @param recipient The address that receives the collected protocol fees
    /// @param amount0 The amount of token0 protocol fees that is withdrawn
    /// @param amount0 The amount of token1 protocol fees that is withdrawn
    event CollectProtocol(address indexed sender, address indexed recipient, uint128 amount0, uint128 amount1);
}

// File: IUniswapV3PoolImmutables.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Pool state that never changes
/// @notice These parameters are fixed for a pool forever, i.e., the methods will always return the same values
interface IUniswapV3PoolImmutables {
    /// @notice The contract that deployed the pool, which must adhere to the IUniswapV3Factory interface
    /// @return The contract address
    function factory() external view returns (address);

    /// @notice The first of the two tokens of the pool, sorted by address
    /// @return The token contract address
    function token0() external view returns (address);

    /// @notice The second of the two tokens of the pool, sorted by address
    /// @return The token contract address
    function token1() external view returns (address);

    /// @notice The pool's fee in hundredths of a bip, i.e. 1e-6
    /// @return The fee
    function fee() external view returns (uint24);

    /// @notice The pool tick spacing
    /// @dev Ticks can only be used at multiples of this value, minimum of 1 and always positive
    /// e.g.: a tickSpacing of 3 means ticks can be initialized every 3rd tick, i.e., ..., -6, -3, 0, 3, 6, ...
    /// This value is an int24 to avoid casting even though it is always positive.
    /// @return The tick spacing
    function tickSpacing() external view returns (int24);

    /// @notice The maximum amount of position liquidity that can use any tick in the range
    /// @dev This parameter is enforced per tick to prevent liquidity from overflowing a uint128 at any point, and
    /// also prevents out-of-range liquidity from being used to prevent adding in-range liquidity to a pool
    /// @return The max amount of liquidity per tick
    function maxLiquidityPerTick() external view returns (uint128);
}

// File: IUniswapV3PoolOwnerActions.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Permissioned pool actions
/// @notice Contains pool methods that may only be called by the factory owner
interface IUniswapV3PoolOwnerActions {
    /// @notice Set the denominator of the protocol's % share of the fees
    /// @param feeProtocol0 new protocol fee for token0 of the pool
    /// @param feeProtocol1 new protocol fee for token1 of the pool
    function setFeeProtocol(uint8 feeProtocol0, uint8 feeProtocol1) external;

    /// @notice Collect the protocol fee accrued to the pool
    /// @param recipient The address to which collected protocol fees should be sent
    /// @param amount0Requested The maximum amount of token0 to send, can be 0 to collect fees in only token1
    /// @param amount1Requested The maximum amount of token1 to send, can be 0 to collect fees in only token0
    /// @return amount0 The protocol fee collected in token0
    /// @return amount1 The protocol fee collected in token1
    function collectProtocol(
        address recipient,
        uint128 amount0Requested,
        uint128 amount1Requested
    ) external returns (uint128 amount0, uint128 amount1);
}

// File: IUniswapV3PoolState.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Pool state that can change
/// @notice These methods compose the pool's state, and can change with any frequency including multiple times
/// per transaction
interface IUniswapV3PoolState {
    /// @notice The 0th storage slot in the pool stores many values, and is exposed as a single method to save gas
    /// when accessed externally.
    /// @return sqrtPriceX96 The current price of the pool as a sqrt(token1/token0) Q64.96 value
    /// tick The current tick of the pool, i.e. according to the last tick transition that was run.
    /// This value may not always be equal to SqrtTickMath.getTickAtSqrtRatio(sqrtPriceX96) if the price is on a tick
    /// boundary.
    /// observationIndex The index of the last oracle observation that was written,
    /// observationCardinality The current maximum number of observations stored in the pool,
    /// observationCardinalityNext The next maximum number of observations, to be updated when the observation.
    /// feeProtocol The protocol fee for both tokens of the pool.
    /// Encoded as two 4 bit values, where the protocol fee of token1 is shifted 4 bits and the protocol fee of token0
    /// is the lower 4 bits. Used as the denominator of a fraction of the swap fee, e.g. 4 means 1/4th of the swap fee.
    /// unlocked Whether the pool is currently locked to reentrancy
    function slot0()
        external
        view
        returns (
            uint160 sqrtPriceX96,
            int24 tick,
            uint16 observationIndex,
            uint16 observationCardinality,
            uint16 observationCardinalityNext,
            uint8 feeProtocol,
            bool unlocked
        );

    /// @notice The fee growth as a Q128.128 fees of token0 collected per unit of liquidity for the entire life of the pool
    /// @dev This value can overflow the uint256
    function feeGrowthGlobal0X128() external view returns (uint256);

    /// @notice The fee growth as a Q128.128 fees of token1 collected per unit of liquidity for the entire life of the pool
    /// @dev This value can overflow the uint256
    function feeGrowthGlobal1X128() external view returns (uint256);

    /// @notice The amounts of token0 and token1 that are owed to the protocol
    /// @dev Protocol fees will never exceed uint128 max in either token
    function protocolFees() external view returns (uint128 token0, uint128 token1);

    /// @notice The currently in range liquidity available to the pool
    /// @dev This value has no relationship to the total liquidity across all ticks
    function liquidity() external view returns (uint128);

    /// @notice Look up information about a specific tick in the pool
    /// @param tick The tick to look up
    /// @return liquidityGross the total amount of position liquidity that uses the pool either as tick lower or
    /// tick upper,
    /// liquidityNet how much liquidity changes when the pool price crosses the tick,
    /// feeGrowthOutside0X128 the fee growth on the other side of the tick from the current tick in token0,
    /// feeGrowthOutside1X128 the fee growth on the other side of the tick from the current tick in token1,
    /// tickCumulativeOutside the cumulative tick value on the other side of the tick from the current tick
    /// secondsPerLiquidityOutsideX128 the seconds spent per liquidity on the other side of the tick from the current tick,
    /// secondsOutside the seconds spent on the other side of the tick from the current tick,
    /// initialized Set to true if the tick is initialized, i.e. liquidityGross is greater than 0, otherwise equal to false.
    /// Outside values can only be used if the tick is initialized, i.e. if liquidityGross is greater than 0.
    /// In addition, these values are only relative and must be used only in comparison to previous snapshots for
    /// a specific position.
    function ticks(int24 tick)
        external
        view
        returns (
            uint128 liquidityGross,
            int128 liquidityNet,
            uint256 feeGrowthOutside0X128,
            uint256 feeGrowthOutside1X128,
            int56 tickCumulativeOutside,
            uint160 secondsPerLiquidityOutsideX128,
            uint32 secondsOutside,
            bool initialized
        );

    /// @notice Returns 256 packed tick initialized boolean values. See TickBitmap for more information
    function tickBitmap(int16 wordPosition) external view returns (uint256);

    /// @notice Returns the information about a position by the position's key
    /// @param key The position's key is a hash of a preimage composed by the owner, tickLower and tickUpper
    /// @return _liquidity The amount of liquidity in the position,
    /// Returns feeGrowthInside0LastX128 fee growth of token0 inside the tick range as of the last mint/burn/poke,
    /// Returns feeGrowthInside1LastX128 fee growth of token1 inside the tick range as of the last mint/burn/poke,
    /// Returns tokensOwed0 the computed amount of token0 owed to the position as of the last mint/burn/poke,
    /// Returns tokensOwed1 the computed amount of token1 owed to the position as of the last mint/burn/poke
    function positions(bytes32 key)
        external
        view
        returns (
            uint128 _liquidity,
            uint256 feeGrowthInside0LastX128,
            uint256 feeGrowthInside1LastX128,
            uint128 tokensOwed0,
            uint128 tokensOwed1
        );

    /// @notice Returns data about a specific observation index
    /// @param index The element of the observations array to fetch
    /// @dev You most likely want to use #observe() instead of this method to get an observation as of some amount of time
    /// ago, rather than at a specific index in the array.
    /// @return blockTimestamp The timestamp of the observation,
    /// Returns tickCumulative the tick multiplied by seconds elapsed for the life of the pool as of the observation timestamp,
    /// Returns secondsPerLiquidityCumulativeX128 the seconds per in range liquidity for the life of the pool as of the observation timestamp,
    /// Returns initialized whether the observation has been initialized and the values are safe to use
    function observations(uint256 index)
        external
        view
        returns (
            uint32 blockTimestamp,
            int56 tickCumulative,
            uint160 secondsPerLiquidityCumulativeX128,
            bool initialized
        );
}

// File: LowGasSafeMath.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.6.12;

/// @title Optimized overflow and underflow safe math operations
/// @notice Contains methods for doing math operations that revert on overflow or underflow for minimal gas cost
library LowGasSafeMath {
    /// @notice Returns x + y, reverts if sum overflows uint256
    /// @param x The augend
    /// @param y The addend
    /// @return z The sum of x and y
    function add(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x + y) >= x);
    }

    /// @notice Returns x - y, reverts if underflows
    /// @param x The minuend
    /// @param y The subtrahend
    /// @return z The difference of x and y
    function sub(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require((z = x - y) <= x);
    }

    /// @notice Returns x * y, reverts if overflows
    /// @param x The multiplicand
    /// @param y The multiplier
    /// @return z The product of x and y
    function mul(uint256 x, uint256 y) internal pure returns (uint256 z) {
        require(x == 0 || (z = x * y) / x == y);
    }

    /// @notice Returns x + y, reverts if overflows or underflows
    /// @param x The augend
    /// @param y The addend
    /// @return z The sum of x and y
    function add(int256 x, int256 y) internal pure returns (int256 z) {
        require((z = x + y) >= x == (y >= 0));
    }

    /// @notice Returns x - y, reverts if overflows or underflows
    /// @param x The minuend
    /// @param y The subtrahend
    /// @return z The difference of x and y
    function sub(int256 x, int256 y) internal pure returns (int256 z) {
        require((z = x - y) <= x == (y >= 0));
    }
}

// File: Math.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

/**
 * @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);
    }
}

// File: OracleLibrary.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

import './FullMath.sol';
import './TickMath.sol';
import './IUniswapV3Pool.sol';
import './LowGasSafeMath.sol';
import './PoolAddress.sol';

/// @title Oracle library
/// @notice Provides functions to integrate with V3 pool oracle
library OracleLibrary {
    /// @notice Fetches time-weighted average tick using Uniswap V3 oracle
    /// @param pool Address of Uniswap V3 pool that we want to observe
    /// @param period Number of seconds in the past to start calculating time-weighted average
    /// @return timeWeightedAverageTick The time-weighted average tick from (block.timestamp - period) to block.timestamp
    function consult(address pool, uint32 period) internal view returns (int24 timeWeightedAverageTick) {
        require(period != 0, 'BP');

        uint32[] memory secondAgos = new uint32[](2);
        secondAgos[0] = period;
        secondAgos[1] = 0;

        (int56[] memory tickCumulatives, ) = IUniswapV3Pool(pool).observe(secondAgos);
        int56 tickCumulativesDelta = tickCumulatives[1] - tickCumulatives[0];

        timeWeightedAverageTick = int24(tickCumulativesDelta / int(uint256(period)));

        // Always round to negative infinity
        if (tickCumulativesDelta < 0 && (tickCumulativesDelta % int(uint256(period)) != 0)) timeWeightedAverageTick--;
    }

    /// @notice Given a tick and a token amount, calculates the amount of token received in exchange
    /// @param tick Tick value used to calculate the quote
    /// @param baseAmount Amount of token to be converted
    /// @param baseToken Address of an ERC20 token contract used as the baseAmount denomination
    /// @param quoteToken Address of an ERC20 token contract used as the quoteAmount denomination
    /// @return quoteAmount Amount of quoteToken received for baseAmount of baseToken
    function getQuoteAtTick(
        int24 tick,
        uint128 baseAmount,
        address baseToken,
        address quoteToken
    ) internal pure returns (uint256 quoteAmount) {
        uint160 sqrtRatioX96 = TickMath.getSqrtRatioAtTick(tick);

        // Calculate quoteAmount with better precision if it doesn't overflow when multiplied by itself
        if (sqrtRatioX96 <= type(uint128).max) {
            uint256 ratioX192 = uint256(sqrtRatioX96) * sqrtRatioX96;
            quoteAmount = baseToken < quoteToken
                ? FullMath.mulDiv(ratioX192, baseAmount, 1 << 192)
                : FullMath.mulDiv(1 << 192, baseAmount, ratioX192);
        } else {
            uint256 ratioX128 = FullMath.mulDiv(sqrtRatioX96, sqrtRatioX96, 1 << 64);
            quoteAmount = baseToken < quoteToken
                ? FullMath.mulDiv(ratioX128, baseAmount, 1 << 128)
                : FullMath.mulDiv(1 << 128, baseAmount, ratioX128);
        }
    }
}

// File: Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

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

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

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

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

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

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

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

// File: Pausable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

import "./Context.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
contract Pausable is Context {
    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

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

    bool private _paused;

    /**
     * @dev Initializes the contract in unpaused state.
     */
    constructor () internal {
        _paused = false;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view returns (bool) {
        return _paused;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        require(!_paused, "Pausable: paused");
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        require(_paused, "Pausable: not paused");
        _;
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}

// File: PoolAddress.sol



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Provides functions for deriving a pool address from the factory, tokens, and the fee
library PoolAddress {
    bytes32 internal constant POOL_INIT_CODE_HASH = 0xe34f199b19b2b4f47f68442619d555527d244f78a3297ea89325f843f87b8b54;

    /// @notice The identifying key of the pool
    struct PoolKey {
        address token0;
        address token1;
        uint24 fee;
    }

    /// @notice Returns PoolKey: the ordered tokens with the matched fee levels
    /// @param tokenA The first token of a pool, unsorted
    /// @param tokenB The second token of a pool, unsorted
    /// @param fee The fee level of the pool
    /// @return Poolkey The pool details with ordered token0 and token1 assignments
    function getPoolKey(
        address tokenA,
        address tokenB,
        uint24 fee
    ) internal pure returns (PoolKey memory) {
        if (tokenA > tokenB) (tokenA, tokenB) = (tokenB, tokenA);
        return PoolKey({token0: tokenA, token1: tokenB, fee: fee});
    }

    /// @notice Deterministically computes the pool address given the factory and PoolKey
    /// @param factory The Uniswap V3 factory contract address
    /// @param key The PoolKey
    /// @return pool The contract address of the V3 pool
    function computeAddress(address factory, PoolKey memory key) internal pure returns (address pool) {
        require(key.token0 < key.token1);
        pool = address(
            uint160(
                uint256(
                    keccak256(
                        abi.encodePacked(
                            hex'ff',
                            factory,
                            keccak256(abi.encode(key.token0, key.token1, key.fee)),
                            POOL_INIT_CODE_HASH
                        )
                    )
                )
            )
        );
    }
}

// File: RelayerRegistry.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.12;
pragma experimental ABIEncoderV2;

import { SafeMath } from "./SafeMath.sol";
import { IERC20 } from "./IERC20.sol";
import { Initializable } from "./Initializable.sol";
import { SafeERC20 } from "./SafeERC20.sol";
import { EnsResolve } from "./ENS.sol";
import { ENSNamehash } from "./ENSNamehash.sol";
import { TORN } from "./TORN.sol";
import { TornadoStakingRewards } from "./TornadoStakingRewards.sol";
import { IENS } from "./IENS.sol";

import "./TornadoRouter.sol";
import "./FeeManager.sol";
import "./ITornadoInstance.sol";

struct RelayerState {
  uint256 balance;
  bytes32 ensHash;
}

/**
 * @notice Registry contract, one of the main contracts of this protocol upgrade.
 *         The contract should store relayers' addresses and data attributed to the
 *         master address of the relayer. This data includes the relayers stake and
 *         his ensHash.
 *         A relayers master address has a number of subaddresses called "workers",
 *         these are all addresses which burn stake in communication with the proxy.
 *         If a relayer is not registered, he is not displayed on the frontend.
 * @dev CONTRACT RISKS:
 *      - if setter functions are compromised, relayer metadata would be at risk, including the noted amount of his balance
 *      - if burn function is compromised, relayers run the risk of being unable to handle withdrawals
 *      - the above risk also applies to the nullify balance function
 * */
contract RelayerRegistry is Initializable, EnsResolve {
  using SafeMath for uint256;
  using SafeERC20 for TORN;
  using ENSNamehash for bytes;

  TORN public immutable torn;
  address public immutable governance;
  IENS public immutable ens;
  TornadoStakingRewards public immutable staking;
  FeeManager public immutable feeManager;

  address public tornadoRouter;
  uint256 public minStakeAmount;

  mapping(address => RelayerState) public relayers;
  mapping(address => address) public workers;

  event RelayerBalanceNullified(address relayer);
  event WorkerRegistered(address relayer, address worker);
  event WorkerUnregistered(address relayer, address worker);
  event StakeAddedToRelayer(address relayer, uint256 amountStakeAdded);
  event StakeBurned(address relayer, uint256 amountBurned);
  event MinimumStakeAmount(uint256 minStakeAmount);
  event RouterRegistered(address tornadoRouter);
  event RelayerRegistered(bytes32 relayer, string ensName, address relayerAddress, uint256 stakedAmount);

  modifier onlyGovernance() {
    require(msg.sender == governance, "only governance");
    _;
  }

  modifier onlyTornadoRouter() {
    require(msg.sender == tornadoRouter, "only proxy");
    _;
  }

  modifier onlyRelayer(address sender, address relayer) {
    require(workers[sender] == relayer, "only relayer");
    _;
  }

  constructor(
    address _torn,
    address _governance,
    address _ens,
    bytes32 _staking,
    bytes32 _feeManager
  ) public {
    torn = TORN(_torn);
    governance = _governance;
    ens = IENS(_ens);
    staking = TornadoStakingRewards(resolve(_staking));
    feeManager = FeeManager(resolve(_feeManager));
  }

  /**
   * @notice initialize function for upgradeability
   * @dev this contract will be deployed behind a proxy and should not assign values at logic address,
   *      params left out because self explainable
   * */
  function initialize(bytes32 _tornadoRouter) external initializer {
    tornadoRouter = resolve(_tornadoRouter);
  }

  /**
   * @notice This function should register a master address and optionally a set of workeres for a relayer + metadata
   * @dev Relayer can't steal other relayers workers since they are registered, and a wallet (msg.sender check) can always unregister itself
   * @param ensName ens name of the relayer
   * @param stake the initial amount of stake in TORN the relayer is depositing
   * */
  function register(
    string calldata ensName,
    uint256 stake,
    address[] calldata workersToRegister
  ) external {
    _register(msg.sender, ensName, stake, workersToRegister);
  }

  /**
   * @dev Register function equivalent with permit-approval instead of regular approve.
   * */
  function registerPermit(
    string calldata ensName,
    uint256 stake,
    address[] calldata workersToRegister,
    address relayer,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external {
    torn.permit(relayer, address(this), stake, deadline, v, r, s);
    _register(relayer, ensName, stake, workersToRegister);
  }

  function _register(
    address relayer,
    string calldata ensName,
    uint256 stake,
    address[] calldata workersToRegister
  ) internal {
    bytes32 ensHash = bytes(ensName).namehash();
    require(relayer == ens.owner(ensHash), "only ens owner");
    require(workers[relayer] == address(0), "cant register again");
    RelayerState storage metadata = relayers[relayer];

    require(metadata.ensHash == bytes32(0), "registered already");
    require(stake >= minStakeAmount, "!min_stake");

    torn.safeTransferFrom(relayer, address(staking), stake);
    emit StakeAddedToRelayer(relayer, stake);

    metadata.balance = stake;
    metadata.ensHash = ensHash;
    workers[relayer] = relayer;

    for (uint256 i = 0; i < workersToRegister.length; i++) {
      address worker = workersToRegister[i];
      _registerWorker(relayer, worker);
    }

    emit RelayerRegistered(ensHash, ensName, relayer, stake);
  }

  /**
   * @notice This function should allow relayers to register more workeres
   * @param relayer Relayer which should send message from any worker which is already registered
   * @param worker Address to register
   * */
  function registerWorker(address relayer, address worker) external onlyRelayer(msg.sender, relayer) {
    _registerWorker(relayer, worker);
  }

  function _registerWorker(address relayer, address worker) internal {
    require(workers[worker] == address(0), "can't steal an address");
    workers[worker] = relayer;
    emit WorkerRegistered(relayer, worker);
  }

  /**
   * @notice This function should allow anybody to unregister an address they own
   * @dev designed this way as to allow someone to unregister themselves in case a relayer misbehaves
   *      - this should be followed by an action like burning relayer stake
   *      - there was an option of allowing the sender to burn relayer stake in case of malicious behaviour, this feature was not included in the end
   *      - reverts if trying to unregister master, otherwise contract would break. in general, there should be no reason to unregister master at all
   * */
  function unregisterWorker(address worker) external {
    if (worker != msg.sender) require(workers[worker] == msg.sender, "only owner of worker");
    require(workers[worker] != worker, "cant unregister master");
    emit WorkerUnregistered(workers[worker], worker);
    workers[worker] = address(0);
  }

  /**
   * @notice This function should allow anybody to stake to a relayer more TORN
   * @param relayer Relayer main address to stake to
   * @param stake Stake to be added to relayer
   * */
  function stakeToRelayer(address relayer, uint256 stake) external {
    _stakeToRelayer(msg.sender, relayer, stake);
  }

  /**
   * @dev stakeToRelayer function equivalent with permit-approval instead of regular approve.
   * @param staker address from that stake is paid
   * */
  function stakeToRelayerPermit(
    address relayer,
    uint256 stake,
    address staker,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external {
    torn.permit(staker, address(this), stake, deadline, v, r, s);
    _stakeToRelayer(staker, relayer, stake);
  }

  function _stakeToRelayer(
    address staker,
    address relayer,
    uint256 stake
  ) internal {
    require(workers[relayer] == relayer, "!registered");
    torn.safeTransferFrom(staker, address(staking), stake);
    relayers[relayer].balance = stake.add(relayers[relayer].balance);
    emit StakeAddedToRelayer(relayer, stake);
  }

  /**
   * @notice This function should burn some relayer stake on withdraw and notify staking of this
   * @dev IMPORTANT FUNCTION:
   *      - This should be only called by the tornado proxy
   *      - Should revert if relayer does not call proxy from valid worker
   *      - Should not overflow
   *      - Should underflow and revert (SafeMath) on not enough stake (balance)
   * @param sender worker to check sender == relayer
   * @param relayer address of relayer who's stake is being burned
   * @param pool instance to get fee for
   * */
  function burn(
    address sender,
    address relayer,
    ITornadoInstance pool
  ) external onlyTornadoRouter {
    address masterAddress = workers[sender];
    if (masterAddress == address(0)) {
      require(workers[relayer] == address(0), "Only custom relayer");
      return;
    }

    require(masterAddress == relayer, "only relayer");
    uint256 toBurn = feeManager.instanceFeeWithUpdate(pool);
    relayers[relayer].balance = relayers[relayer].balance.sub(toBurn);
    staking.addBurnRewards(toBurn);
    emit StakeBurned(relayer, toBurn);
  }

  /**
   * @notice This function should allow governance to set the minimum stake amount
   * @param minAmount new minimum stake amount
   * */
  function setMinStakeAmount(uint256 minAmount) external onlyGovernance {
    minStakeAmount = minAmount;
    emit MinimumStakeAmount(minAmount);
  }

  /**
   * @notice This function should allow governance to set a new tornado proxy address
   * @param tornadoRouterAddress address of the new proxy
   * */
  function setTornadoRouter(address tornadoRouterAddress) external onlyGovernance {
    tornadoRouter = tornadoRouterAddress;
    emit RouterRegistered(tornadoRouterAddress);
  }

  /**
   * @notice This function should allow governance to nullify a relayers balance
   * @dev IMPORTANT FUNCTION:
   *      - Should nullify the balance
   *      - Adding nullified balance as rewards was refactored to allow for the flexibility of these funds (for gov to operate with them)
   * @param relayer address of relayer who's balance is to nullify
   * */
  function nullifyBalance(address relayer) external onlyGovernance {
    address masterAddress = workers[relayer];
    require(relayer == masterAddress, "must be master");
    relayers[masterAddress].balance = 0;
    emit RelayerBalanceNullified(relayer);
  }

  /**
   * @notice This function should check if a worker is associated with a relayer
   * @param toResolve address to check
   * @return true if is associated
   * */
  function isRelayer(address toResolve) external view returns (bool) {
    return workers[toResolve] != address(0);
  }

  /**
   * @notice This function should check if a worker is registered to the relayer stated
   * @param relayer relayer to check
   * @param toResolve address to check
   * @return true if registered
   * */
  function isRelayerRegistered(address relayer, address toResolve) external view returns (bool) {
    return workers[toResolve] == relayer;
  }

  /**
   * @notice This function should get a relayers ensHash
   * @param relayer address to fetch for
   * @return relayer's ensHash
   * */
  function getRelayerEnsHash(address relayer) external view returns (bytes32) {
    return relayers[workers[relayer]].ensHash;
  }

  /**
   * @notice This function should get a relayers balance
   * @param relayer relayer who's balance is to fetch
   * @return relayer's balance
   * */
  function getRelayerBalance(address relayer) external view returns (uint256) {
    return relayers[workers[relayer]].balance;
  }
}

// File: SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

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

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

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

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

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

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

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

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

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

// File: SafeMath.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;

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

        return c;
    }

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

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

        return c;
    }

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

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

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

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



// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.5.0;

/// @title Math library for computing sqrt prices from ticks and vice versa
/// @notice Computes sqrt price for ticks of size 1.0001, i.e. sqrt(1.0001^tick) as fixed point Q64.96 numbers. Supports
/// prices between 2**-128 and 2**128
library TickMath {
    /// @dev The minimum tick that may be passed to #getSqrtRatioAtTick computed from log base 1.0001 of 2**-128
    int24 internal constant MIN_TICK = -887272;
    /// @dev The maximum tick that may be passed to #getSqrtRatioAtTick computed from log base 1.0001 of 2**128
    int24 internal constant MAX_TICK = -MIN_TICK;

    /// @dev The minimum value that can be returned from #getSqrtRatioAtTick. Equivalent to getSqrtRatioAtTick(MIN_TICK)
    uint160 internal constant MIN_SQRT_RATIO = 4295128739;
    /// @dev The maximum value that can be returned from #getSqrtRatioAtTick. Equivalent to getSqrtRatioAtTick(MAX_TICK)
    uint160 internal constant MAX_SQRT_RATIO = 1461446703485210103287273052203988822378723970342;

    /// @notice Calculates sqrt(1.0001^tick) * 2^96
    /// @dev Throws if |tick| > max tick
    /// @param tick The input tick for the above formula
    /// @return sqrtPriceX96 A Fixed point Q64.96 number representing the sqrt of the ratio of the two assets (token1/token0)
    /// at the given tick
    function getSqrtRatioAtTick(int24 tick) internal pure returns (uint160 sqrtPriceX96) {
        uint256 absTick = tick < 0 ? uint256(-int256(tick)) : uint256(int256(tick));
        require(absTick <= uint256(int(MAX_TICK)), 'T');

        uint256 ratio = absTick & 0x1 != 0 ? 0xfffcb933bd6fad37aa2d162d1a594001 : 0x100000000000000000000000000000000;
        if (absTick & 0x2 != 0) ratio = (ratio * 0xfff97272373d413259a46990580e213a) >> 128;
        if (absTick & 0x4 != 0) ratio = (ratio * 0xfff2e50f5f656932ef12357cf3c7fdcc) >> 128;
        if (absTick & 0x8 != 0) ratio = (ratio * 0xffe5caca7e10e4e61c3624eaa0941cd0) >> 128;
        if (absTick & 0x10 != 0) ratio = (ratio * 0xffcb9843d60f6159c9db58835c926644) >> 128;
        if (absTick & 0x20 != 0) ratio = (ratio * 0xff973b41fa98c081472e6896dfb254c0) >> 128;
        if (absTick & 0x40 != 0) ratio = (ratio * 0xff2ea16466c96a3843ec78b326b52861) >> 128;
        if (absTick & 0x80 != 0) ratio = (ratio * 0xfe5dee046a99a2a811c461f1969c3053) >> 128;
        if (absTick & 0x100 != 0) ratio = (ratio * 0xfcbe86c7900a88aedcffc83b479aa3a4) >> 128;
        if (absTick & 0x200 != 0) ratio = (ratio * 0xf987a7253ac413176f2b074cf7815e54) >> 128;
        if (absTick & 0x400 != 0) ratio = (ratio * 0xf3392b0822b70005940c7a398e4b70f3) >> 128;
        if (absTick & 0x800 != 0) ratio = (ratio * 0xe7159475a2c29b7443b29c7fa6e889d9) >> 128;
        if (absTick & 0x1000 != 0) ratio = (ratio * 0xd097f3bdfd2022b8845ad8f792aa5825) >> 128;
        if (absTick & 0x2000 != 0) ratio = (ratio * 0xa9f746462d870fdf8a65dc1f90e061e5) >> 128;
        if (absTick & 0x4000 != 0) ratio = (ratio * 0x70d869a156d2a1b890bb3df62baf32f7) >> 128;
        if (absTick & 0x8000 != 0) ratio = (ratio * 0x31be135f97d08fd981231505542fcfa6) >> 128;
        if (absTick & 0x10000 != 0) ratio = (ratio * 0x9aa508b5b7a84e1c677de54f3e99bc9) >> 128;
        if (absTick & 0x20000 != 0) ratio = (ratio * 0x5d6af8dedb81196699c329225ee604) >> 128;
        if (absTick & 0x40000 != 0) ratio = (ratio * 0x2216e584f5fa1ea926041bedfe98) >> 128;
        if (absTick & 0x80000 != 0) ratio = (ratio * 0x48a170391f7dc42444e8fa2) >> 128;

        if (tick > 0) ratio = type(uint256).max / ratio;

        // this divides by 1<<32 rounding up to go from a Q128.128 to a Q128.96.
        // we then downcast because we know the result always fits within 160 bits due to our tick input constraint
        // we round up in the division so getTickAtSqrtRatio of the output price is always consistent
        sqrtPriceX96 = uint160((ratio >> 32) + (ratio % (1 << 32) == 0 ? 0 : 1));
    }

    /// @notice Calculates the greatest tick value such that getRatioAtTick(tick) <= ratio
    /// @dev Throws in case sqrtPriceX96 < MIN_SQRT_RATIO, as MIN_SQRT_RATIO is the lowest value getRatioAtTick may
    /// ever return.
    /// @param sqrtPriceX96 The sqrt ratio for which to compute the tick as a Q64.96
    /// @return tick The greatest tick for which the ratio is less than or equal to the input ratio
    function getTickAtSqrtRatio(uint160 sqrtPriceX96) internal pure returns (int24 tick) {
        // second inequality must be < because the price can never reach the price at the max tick
        require(sqrtPriceX96 >= MIN_SQRT_RATIO && sqrtPriceX96 < MAX_SQRT_RATIO, 'R');
        uint256 ratio = uint256(sqrtPriceX96) << 32;

        uint256 r = ratio;
        uint256 msb = 0;

        assembly {
            let f := shl(7, gt(r, 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF))
            msb := or(msb, f)
            r := shr(f, r)
        }
        assembly {
            let f := shl(6, gt(r, 0xFFFFFFFFFFFFFFFF))
            msb := or(msb, f)
            r := shr(f, r)
        }
        assembly {
            let f := shl(5, gt(r, 0xFFFFFFFF))
            msb := or(msb, f)
            r := shr(f, r)
        }
        assembly {
            let f := shl(4, gt(r, 0xFFFF))
            msb := or(msb, f)
            r := shr(f, r)
        }
        assembly {
            let f := shl(3, gt(r, 0xFF))
            msb := or(msb, f)
            r := shr(f, r)
        }
        assembly {
            let f := shl(2, gt(r, 0xF))
            msb := or(msb, f)
            r := shr(f, r)
        }
        assembly {
            let f := shl(1, gt(r, 0x3))
            msb := or(msb, f)
            r := shr(f, r)
        }
        assembly {
            let f := gt(r, 0x1)
            msb := or(msb, f)
        }

        if (msb >= 128) r = ratio >> (msb - 127);
        else r = ratio << (127 - msb);

        int256 log_2 = (int256(msb) - 128) << 64;

        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(63, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(62, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(61, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(60, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(59, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(58, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(57, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(56, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(55, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(54, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(53, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(52, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(51, f))
            r := shr(f, r)
        }
        assembly {
            r := shr(127, mul(r, r))
            let f := shr(128, r)
            log_2 := or(log_2, shl(50, f))
        }

        int256 log_sqrt10001 = log_2 * 255738958999603826347141; // 128.128 number

        int24 tickLow = int24((log_sqrt10001 - 3402992956809132418596140100660247210) >> 128);
        int24 tickHi = int24((log_sqrt10001 + 291339464771989622907027621153398088495) >> 128);

        tick = tickLow == tickHi ? tickLow : getSqrtRatioAtTick(tickHi) <= sqrtPriceX96 ? tickHi : tickLow;
    }
}

// File: TORN.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.0;
pragma experimental ABIEncoderV2;

import "./IERC20.sol";
import "./ERC20.sol";
import "./ERC20Burnable.sol";
import "./SafeERC20.sol";
import "./Ownable.sol";
import "./Pausable.sol";
import "./Math.sol";
import "./ERC20Permit.sol";
import "./ENS.sol";

contract TORN is ERC20("TornadoCash", "TORN"), ERC20Burnable, ERC20Permit, Pausable, EnsResolve {
  using SafeERC20 for IERC20;

  uint256 public immutable canUnpauseAfter;
  address public immutable governance;
  mapping(address => bool) public allowedTransferee;

  event Allowed(address target);
  event Disallowed(address target);

  struct Recipient {
    bytes32 to;
    uint256 amount;
  }

  constructor(
    bytes32 _governance,
    uint256 _pausePeriod,
    Recipient[] memory _vestings
  ) public {
    address _resolvedGovernance = resolve(_governance);
    governance = _resolvedGovernance;
    allowedTransferee[_resolvedGovernance] = true;

    for (uint256 i = 0; i < _vestings.length; i++) {
      address to = resolve(_vestings[i].to);
      _mint(to, _vestings[i].amount);
      allowedTransferee[to] = true;
    }

    canUnpauseAfter = blockTimestamp().add(_pausePeriod);
    _pause();
    require(totalSupply() == 10000000 ether, "TORN: incorrect distribution");
  }

  modifier onlyGovernance() {
    require(_msgSender() == governance, "TORN: only governance can perform this action");
    _;
  }

  function changeTransferability(bool decision) public onlyGovernance {
    require(blockTimestamp() > canUnpauseAfter, "TORN: cannot change transferability yet");
    if (decision) {
      _unpause();
    } else {
      _pause();
    }
  }

  function addToAllowedList(address[] memory target) public onlyGovernance {
    for (uint256 i = 0; i < target.length; i++) {
      allowedTransferee[target[i]] = true;
      emit Allowed(target[i]);
    }
  }

  function removeFromAllowedList(address[] memory target) public onlyGovernance {
    for (uint256 i = 0; i < target.length; i++) {
      allowedTransferee[target[i]] = false;
      emit Disallowed(target[i]);
    }
  }

  function _beforeTokenTransfer(
    address from,
    address to,
    uint256 amount
  ) internal override {
    super._beforeTokenTransfer(from, to, amount);
    require(!paused() || allowedTransferee[from] || allowedTransferee[to], "TORN: paused");
    require(to != address(this), "TORN: invalid recipient");
  }

  /// @dev Method to claim junk and accidentally sent tokens
  function rescueTokens(
    IERC20 _token,
    address payable _to,
    uint256 _balance
  ) external onlyGovernance {
    require(_to != address(0), "TORN: can not send to zero address");

    if (_token == IERC20(0)) {
      // for Ether
      uint256 totalBalance = address(this).balance;
      uint256 balance = _balance == 0 ? totalBalance : Math.min(totalBalance, _balance);
      _to.transfer(balance);
    } else {
      // any other erc20
      uint256 totalBalance = _token.balanceOf(address(this));
      uint256 balance = _balance == 0 ? totalBalance : Math.min(totalBalance, _balance);
      require(balance > 0, "TORN: trying to send 0 balance");
      _token.safeTransfer(_to, balance);
    }
  }
}

// File: TornadoRouter.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;
pragma experimental ABIEncoderV2;

import "./IERC20.sol";
import "./SafeERC20.sol";
import "./Math.sol";
import "./ITornadoInstance.sol";
import "./ENS.sol";
import "./InstanceRegistry.sol";
import "./RelayerRegistry.sol";

contract TornadoRouter is EnsResolve {
  using SafeERC20 for IERC20;

  event EncryptedNote(address indexed sender, bytes encryptedNote);
  event StakeBurned(address relayer, uint256 amountBurned);

  address public immutable governance;
  InstanceRegistry public immutable instanceRegistry;
  RelayerRegistry public immutable relayerRegistry;

  modifier onlyGovernance() {
    require(msg.sender == governance, "Not authorized");
    _;
  }

  modifier onlyInstanceRegistry() {
    require(msg.sender == address(instanceRegistry), "Not authorized");
    _;
  }

  constructor(
    address _governance,
    InstanceRegistry _instanceRegistry,
    RelayerRegistry _relayerRegistry
  ) public {
    governance = _governance;
    instanceRegistry = _instanceRegistry;
    relayerRegistry = _relayerRegistry;
  }

  function deposit(
    ITornadoInstance _tornado,
    bytes32 _commitment,
    bytes calldata _encryptedNote
  ) public payable virtual {
    (bool isERC20, IERC20 token, InstanceRegistry.InstanceState state, , ) = instanceRegistry.instances(_tornado);
    require(state != InstanceRegistry.InstanceState.DISABLED, "The instance is not supported");

    if (isERC20) {
      token.safeTransferFrom(msg.sender, address(this), _tornado.denomination());
    }
    _tornado.deposit{ value: msg.value }(_commitment);
    emit EncryptedNote(msg.sender, _encryptedNote);
  }

  function withdraw(
    ITornadoInstance _tornado,
    bytes calldata _proof,
    bytes32 _root,
    bytes32 _nullifierHash,
    address payable _recipient,
    address payable _relayer,
    uint256 _fee,
    uint256 _refund
  ) public payable virtual {
    (, , InstanceRegistry.InstanceState state, , ) = instanceRegistry.instances(_tornado);
    require(state != InstanceRegistry.InstanceState.DISABLED, "The instance is not supported");
    uint256 toBurn = relayerRegistry.feeManager().instanceFeeWithUpdate(_tornado);
    emit StakeBurned(_relayer, toBurn);

    _tornado.withdraw{ value: msg.value }(_proof, _root, _nullifierHash, _recipient, _relayer, _fee, _refund);
  }

  /**
   * @dev Sets `amount` allowance of `_spender` over the router's (this contract) tokens.
   */
  function approveExactToken(
    IERC20 _token,
    address _spender,
    uint256 _amount
  ) external onlyInstanceRegistry {
    _token.safeApprove(_spender, _amount);
  }

  /**
   * @notice Manually backup encrypted notes
   */
  function backupNotes(bytes[] calldata _encryptedNotes) external virtual {
    for (uint256 i = 0; i < _encryptedNotes.length; i++) {
      emit EncryptedNote(msg.sender, _encryptedNotes[i]);
    }
  }

  /// @dev Method to claim junk and accidentally sent tokens
  function rescueTokens(
    IERC20 _token,
    address payable _to,
    uint256 _amount
  ) external virtual onlyGovernance {
    require(_to != address(0), "TORN: can not send to zero address");

    if (_token == IERC20(0)) {
      // for Ether
      uint256 totalBalance = address(this).balance;
      uint256 balance = Math.min(totalBalance, _amount);
      _to.transfer(balance);
    } else {
      // any other erc20
      uint256 totalBalance = _token.balanceOf(address(this));
      uint256 balance = Math.min(totalBalance, _amount);
      require(balance > 0, "TORN: trying to send 0 balance");
      _token.safeTransfer(_to, balance);
    }
  }
}

// File: TornadoStakingRewards.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.12;
pragma experimental ABIEncoderV2;

import { IERC20 } from "./IERC20.sol";
import { SafeMath } from "./SafeMath.sol";
import { SafeERC20 } from "./SafeERC20.sol";
import { Initializable } from "./Initializable.sol";
import { EnsResolve } from "./ENS.sol";
import { ITornadoGovernance } from "./ITornadoGovernance.sol";

/**
 * @notice This is the staking contract of the governance staking upgrade.
 *         This contract should hold the staked funds which are received upon relayer registration,
 *         and properly attribute rewards to addresses without security issues.
 * @dev CONTRACT RISKS:
 *      - Relayer staked TORN at risk if contract is compromised.
 * */
contract TornadoStakingRewards is Initializable, EnsResolve {
  using SafeMath for uint256;
  using SafeERC20 for IERC20;

  /// @notice 1e25
  uint256 public immutable ratioConstant;
  ITornadoGovernance public immutable Governance;
  IERC20 public immutable torn;
  address public immutable relayerRegistry;

  /// @notice the sum torn_burned_i/locked_amount_i*coefficient where i is incremented at each burn
  uint256 public accumulatedRewardPerTorn;
  /// @notice notes down accumulatedRewardPerTorn for an address on a lock/unlock/claim
  mapping(address => uint256) public accumulatedRewardRateOnLastUpdate;
  /// @notice notes down how much an account may claim
  mapping(address => uint256) public accumulatedRewards;

  event RewardsUpdated(address indexed account, uint256 rewards);
  event RewardsClaimed(address indexed account, uint256 rewardsClaimed);

  modifier onlyGovernance() {
    require(msg.sender == address(Governance), "only governance");
    _;
  }

  constructor(
    address governanceAddress,
    address tornAddress,
    bytes32 _relayerRegistry
  ) public {
    Governance = ITornadoGovernance(governanceAddress);
    torn = IERC20(tornAddress);
    relayerRegistry = resolve(_relayerRegistry);
    ratioConstant = IERC20(tornAddress).totalSupply();
  }

  /**
   * @notice This function should safely send a user his rewards.
   * @dev IMPORTANT FUNCTION:
   *      We know that rewards are going to be updated every time someone locks or unlocks
   *      so we know that this function can't be used to falsely increase the amount of
   *      lockedTorn by locking in governance and subsequently calling it.
   *      - set rewards to 0 greedily
   */
  function getReward() external {
    uint256 rewards = _updateReward(msg.sender, Governance.lockedBalance(msg.sender));
    rewards = rewards.add(accumulatedRewards[msg.sender]);
    accumulatedRewards[msg.sender] = 0;
    torn.safeTransfer(msg.sender, rewards);
    emit RewardsClaimed(msg.sender, rewards);
  }

  /**
   * @notice This function should increment the proper amount of rewards per torn for the contract
   * @dev IMPORTANT FUNCTION:
   *      - calculation must not overflow with extreme values
   *        (amount <= 1e25) * 1e25 / (balance of vault <= 1e25) -> (extreme values)
   * @param amount amount to add to the rewards
   */
  function addBurnRewards(uint256 amount) external {
    require(msg.sender == address(Governance) || msg.sender == relayerRegistry, "unauthorized");
    accumulatedRewardPerTorn = accumulatedRewardPerTorn.add(
      amount.mul(ratioConstant).div(torn.balanceOf(address(Governance.userVault())))
    );
  }

  /**
   * @notice This function should allow governance to properly update the accumulated rewards rate for an account
   * @param account address of account to update data for
   * @param amountLockedBeforehand the balance locked beforehand in the governance contract
   * */
  function updateRewardsOnLockedBalanceChange(address account, uint256 amountLockedBeforehand) external onlyGovernance {
    uint256 claimed = _updateReward(account, amountLockedBeforehand);
    accumulatedRewards[account] = accumulatedRewards[account].add(claimed);
  }

  /**
   * @notice This function should allow governance rescue tokens from the staking rewards contract
   * */
  function withdrawTorn(uint256 amount) external onlyGovernance {
    if (amount == type(uint256).max) amount = torn.balanceOf(address(this));
    torn.safeTransfer(address(Governance), amount);
  }

  /**
   * @notice This function should calculated the proper amount of rewards attributed to user since the last update
   * @dev IMPORTANT FUNCTION:
   *      - calculation must not overflow with extreme values
   *        (accumulatedReward <= 1e25) * (lockedBeforehand <= 1e25) / 1e25
   *      - result may go to 0, since this implies on 1 TORN locked => accumulatedReward <= 1e7, meaning a very small reward
   * @param account address of account to calculate rewards for
   * @param amountLockedBeforehand the balance locked beforehand in the governance contract
   * @return claimed the rewards attributed to user since the last update
   */
  function _updateReward(address account, uint256 amountLockedBeforehand) private returns (uint256 claimed) {
    if (amountLockedBeforehand != 0)
      claimed = (accumulatedRewardPerTorn.sub(accumulatedRewardRateOnLastUpdate[account])).mul(amountLockedBeforehand).div(
        ratioConstant
      );
    accumulatedRewardRateOnLastUpdate[account] = accumulatedRewardPerTorn;
    emit RewardsUpdated(account, claimed);
  }

  /**
   * @notice This function should show a user his rewards.
   * @param account address of account to calculate rewards for
   */
  function checkReward(address account) external view returns (uint256 rewards) {
    uint256 amountLocked = Governance.lockedBalance(account);
    if (amountLocked != 0)
      rewards = (accumulatedRewardPerTorn.sub(accumulatedRewardRateOnLastUpdate[account])).mul(amountLocked).div(ratioConstant);
    rewards = rewards.add(accumulatedRewards[account]);
  }
}

// File: UniswapV3OracleHelper.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.6.12;

import { OracleLibrary } from "./OracleLibrary.sol";
import { IUniswapV3Factory } from "./IUniswapV3Factory.sol";
import { LowGasSafeMath } from "./LowGasSafeMath.sol";

interface IERC20Decimals {
  function decimals() external view returns (uint8);
}

library UniswapV3OracleHelper {
  using LowGasSafeMath for uint256;

  IUniswapV3Factory internal constant UniswapV3Factory = IUniswapV3Factory(0x1F98431c8aD98523631AE4a59f267346ea31F984);
  address internal constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
  uint256 internal constant RATIO_DIVIDER = 1e18;

  /**
   * @notice This function should return the price of baseToken in quoteToken, as in: quote/base (WETH/TORN)
   * @dev uses the Uniswap written OracleLibrary "getQuoteAtTick", does not call external libraries,
   *      uses decimals() for the correct power of 10
   * @param baseToken token which will be denominated in quote token
   * @param quoteToken token in which price will be denominated
   * @param fee the uniswap pool fee, pools have different fees so this is a pool selector for our usecase
   * @param period the amount of seconds we are going to look into the past for the new token price
   * @return returns the price of baseToken in quoteToken
   * */
  function getPriceOfTokenInToken(
    address baseToken,
    address quoteToken,
    uint24 fee,
    uint32 period
  ) internal view returns (uint256) {
    uint128 base = uint128(10)**uint128(IERC20Decimals(quoteToken).decimals());
    if (baseToken == quoteToken) return base;
    else
      return
        OracleLibrary.getQuoteAtTick(
          OracleLibrary.consult(UniswapV3Factory.getPool(baseToken, quoteToken, fee), period),
          base,
          baseToken,
          quoteToken
        );
  }

  /**
   * @notice This function should return the price of token in WETH
   * @dev simply feeds WETH in to the above function
   * @param token token which will be denominated in WETH
   * @param fee the uniswap pool fee, pools have different fees so this is a pool selector for our usecase
   * @param period the amount of seconds we are going to look into the past for the new token price
   * @return returns the price of token in WETH
   * */
  function getPriceOfTokenInWETH(
    address token,
    uint24 fee,
    uint32 period
  ) internal view returns (uint256) {
    return getPriceOfTokenInToken(token, WETH, fee, period);
  }

  /**
   * @notice This function should return the price of WETH in token
   * @dev simply feeds WETH into getPriceOfTokenInToken
   * @param token token which WETH will be denominated in
   * @param fee the uniswap pool fee, pools have different fees so this is a pool selector for our usecase
   * @param period the amount of seconds we are going to look into the past for the new token price
   * @return returns the price of token in WETH
   * */
  function getPriceOfWETHInToken(
    address token,
    uint24 fee,
    uint32 period
  ) internal view returns (uint256) {
    return getPriceOfTokenInToken(WETH, token, fee, period);
  }

  /**
   * @notice This function returns the price of token[0] in token[1], but more precisely and importantly the price ratio of the tokens in WETH
   * @dev this is done as to always have good prices due to WETH-token pools mostly always having the most liquidity
   * @param tokens array of tokens to get ratio for
   * @param fees the uniswap pool FEES, since these are two independent tokens
   * @param period the amount of seconds we are going to look into the past for the new token price
   * @return returns the price of token[0] in token[1]
   * */
  function getPriceRatioOfTokens(
    address[2] memory tokens,
    uint24[2] memory fees,
    uint32 period
  ) internal view returns (uint256) {
    return
      getPriceOfTokenInWETH(tokens[0], fees[0], period).mul(RATIO_DIVIDER) / getPriceOfTokenInWETH(tokens[1], fees[1], period);
  }
}