// Dependency file: @openzeppelin/contracts/token/ERC20/SafeERC20.sol

// SPDX-License-Identifier: MIT

// pragma solidity ^0.6.0;

// import "./IERC20.sol";
// import "../../math/SafeMath.sol";
// import "../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for 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");
        }
    }
}

// Dependency file: contracts/interfaces/ISetValuer.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
// pragma solidity 0.6.10;

// import { ISetToken } from "../interfaces/ISetToken.sol";

interface ISetValuer {
    function calculateSetTokenValuation(ISetToken _setToken, address _quoteAsset) external view returns (uint256);
}
// Dependency file: contracts/interfaces/IPriceOracle.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
// pragma solidity 0.6.10;

/**
 * @title IPriceOracle
 * @author Set Protocol
 *
 * Interface for interacting with PriceOracle
 */
interface IPriceOracle {

    /* ============ Functions ============ */

    function getPrice(address _assetOne, address _assetTwo) external view returns (uint256);
    function masterQuoteAsset() external view returns (address);
}
// Dependency file: contracts/interfaces/IIntegrationRegistry.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
// pragma solidity 0.6.10;

interface IIntegrationRegistry {
    function addIntegration(address _module, string memory _id, address _wrapper) external;
    function getIntegrationAdapter(address _module, string memory _id) external view returns(address);
    function getIntegrationAdapterWithHash(address _module, bytes32 _id) external view returns(address);
    function isValidIntegration(address _module, string memory _id) external view returns(bool);
}
// Dependency file: contracts/interfaces/IModule.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
// pragma solidity 0.6.10;


/**
 * @title IModule
 * @author Set Protocol
 *
 * Interface for interacting with Modules.
 */
interface IModule {
    /**
     * Called by a SetToken to notify that this module was removed from the Set token. Any logic can be included
     * in case checks need to be made or state needs to be cleared.
     */
    function removeModule() external;
}
// Dependency file: contracts/lib/ExplicitERC20.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

// pragma solidity 0.6.10;

// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
// import { SafeERC20 } from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
// import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";

/**
 * @title ExplicitERC20
 * @author Set Protocol
 *
 * Utility functions for ERC20 transfers that require the explicit amount to be transferred.
 */
library ExplicitERC20 {
    using SafeMath for uint256;

    /**
     * When given allowance, transfers a token from the "_from" to the "_to" of quantity "_quantity".
     * Ensures that the recipient has received the correct quantity (ie no fees taken on transfer)
     *
     * @param _token           ERC20 token to approve
     * @param _from            The account to transfer tokens from
     * @param _to              The account to transfer tokens to
     * @param _quantity        The quantity to transfer
     */
    function transferFrom(
        IERC20 _token,
        address _from,
        address _to,
        uint256 _quantity
    )
        internal
    {
        // Call specified ERC20 contract to transfer tokens (via proxy).
        if (_quantity > 0) {
            uint256 existingBalance = _token.balanceOf(_to);

            SafeERC20.safeTransferFrom(
                _token,
                _from,
                _to,
                _quantity
            );

            uint256 newBalance = _token.balanceOf(_to);

            // Verify transfer quantity is reflected in balance
            require(
                newBalance == existingBalance.add(_quantity),
                "Invalid post transfer balance"
            );
        }
    }
}

// Dependency file: @openzeppelin/contracts/utils/Address.sol

// pragma solidity ^0.6.2;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [// importANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * // importANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @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);
            }
        }
    }
}

// Dependency file: @openzeppelin/contracts/GSN/Context.sol

// pragma solidity ^0.6.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
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;
    }
}

// Dependency file: contracts/protocol/lib/ResourceIdentifier.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

// pragma solidity 0.6.10;

// import { IController } from "../../interfaces/IController.sol";
// import { IIntegrationRegistry } from "../../interfaces/IIntegrationRegistry.sol";
// import { IPriceOracle } from "../../interfaces/IPriceOracle.sol";
// import { ISetValuer } from "../../interfaces/ISetValuer.sol";

/**
 * @title ResourceIdentifier
 * @author Set Protocol
 *
 * A collection of utility functions to fetch information related to Resource contracts in the system
 */
library ResourceIdentifier {

    // IntegrationRegistry will always be resource ID 0 in the system
    uint256 constant internal INTEGRATION_REGISTRY_RESOURCE_ID = 0;
    // PriceOracle will always be resource ID 1 in the system
    uint256 constant internal PRICE_ORACLE_RESOURCE_ID = 1;
    // SetValuer resource will always be resource ID 2 in the system
    uint256 constant internal SET_VALUER_RESOURCE_ID = 2;

    /* ============ Internal ============ */

    /**
     * Gets the instance of integration registry stored on Controller. Note: IntegrationRegistry is stored as index 0 on
     * the Controller
     */
    function getIntegrationRegistry(IController _controller) internal view returns (IIntegrationRegistry) {
        return IIntegrationRegistry(_controller.resourceId(INTEGRATION_REGISTRY_RESOURCE_ID));
    }

    /**
     * Gets instance of price oracle on Controller. Note: PriceOracle is stored as index 1 on the Controller
     */
    function getPriceOracle(IController _controller) internal view returns (IPriceOracle) {
        return IPriceOracle(_controller.resourceId(PRICE_ORACLE_RESOURCE_ID));
    }

    /**
     * Gets the instance of Set valuer on Controller. Note: SetValuer is stored as index 2 on the Controller
     */
    function getSetValuer(IController _controller) internal view returns (ISetValuer) {
        return ISetValuer(_controller.resourceId(SET_VALUER_RESOURCE_ID));
    }
}
// Dependency file: contracts/lib/PreciseUnitMath.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

// pragma solidity 0.6.10;
// pragma experimental ABIEncoderV2;

// import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
// import { SignedSafeMath } from "@openzeppelin/contracts/math/SignedSafeMath.sol";


/**
 * @title PreciseUnitMath
 * @author Set Protocol
 *
 * Arithmetic for fixed-point numbers with 18 decimals of precision. Some functions taken from
 * dYdX's BaseMath library.
 *
 * CHANGELOG:
 * - 9/21/20: Added safePower function
 */
library PreciseUnitMath {
    using SafeMath for uint256;
    using SignedSafeMath for int256;

    // The number One in precise units.
    uint256 constant internal PRECISE_UNIT = 10 ** 18;
    int256 constant internal PRECISE_UNIT_INT = 10 ** 18;

    // Max unsigned integer value
    uint256 constant internal MAX_UINT_256 = type(uint256).max;
    // Max and min signed integer value
    int256 constant internal MAX_INT_256 = type(int256).max;
    int256 constant internal MIN_INT_256 = type(int256).min;

    /**
     * @dev Getter function since constants can't be read directly from libraries.
     */
    function preciseUnit() internal pure returns (uint256) {
        return PRECISE_UNIT;
    }

    /**
     * @dev Getter function since constants can't be read directly from libraries.
     */
    function preciseUnitInt() internal pure returns (int256) {
        return PRECISE_UNIT_INT;
    }

    /**
     * @dev Getter function since constants can't be read directly from libraries.
     */
    function maxUint256() internal pure returns (uint256) {
        return MAX_UINT_256;
    }

    /**
     * @dev Getter function since constants can't be read directly from libraries.
     */
    function maxInt256() internal pure returns (int256) {
        return MAX_INT_256;
    }

    /**
     * @dev Getter function since constants can't be read directly from libraries.
     */
    function minInt256() internal pure returns (int256) {
        return MIN_INT_256;
    }

    /**
     * @dev Multiplies value a by value b (result is rounded down). It's assumed that the value b is the significand
     * of a number with 18 decimals precision.
     */
    function preciseMul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a.mul(b).div(PRECISE_UNIT);
    }

    /**
     * @dev Multiplies value a by value b (result is rounded towards zero). It's assumed that the value b is the
     * significand of a number with 18 decimals precision.
     */
    function preciseMul(int256 a, int256 b) internal pure returns (int256) {
        return a.mul(b).div(PRECISE_UNIT_INT);
    }

    /**
     * @dev Multiplies value a by value b (result is rounded up). It's assumed that the value b is the significand
     * of a number with 18 decimals precision.
     */
    function preciseMulCeil(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0 || b == 0) {
            return 0;
        }
        return a.mul(b).sub(1).div(PRECISE_UNIT).add(1);
    }

    /**
     * @dev Divides value a by value b (result is rounded down).
     */
    function preciseDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        return a.mul(PRECISE_UNIT).div(b);
    }


    /**
     * @dev Divides value a by value b (result is rounded towards 0).
     */
    function preciseDiv(int256 a, int256 b) internal pure returns (int256) {
        return a.mul(PRECISE_UNIT_INT).div(b);
    }

    /**
     * @dev Divides value a by value b (result is rounded up or away from 0).
     */
    function preciseDivCeil(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b != 0, "Cant divide by 0");

        return a > 0 ? a.mul(PRECISE_UNIT).sub(1).div(b).add(1) : 0;
    }

    /**
     * @dev Divides value a by value b (result is rounded down - positive numbers toward 0 and negative away from 0).
     */
    function divDown(int256 a, int256 b) internal pure returns (int256) {
        require(b != 0, "Cant divide by 0");
        require(a != MIN_INT_256 || b != -1, "Invalid input");

        int256 result = a.div(b);
        if (a ^ b < 0 && a % b != 0) {
            result -= 1;
        }

        return result;
    }

    /**
     * @dev Multiplies value a by value b where rounding is towards the lesser number. 
     * (positive values are rounded towards zero and negative values are rounded away from 0). 
     */
    function conservativePreciseMul(int256 a, int256 b) internal pure returns (int256) {
        return divDown(a.mul(b), PRECISE_UNIT_INT);
    }

    /**
     * @dev Divides value a by value b where rounding is towards the lesser number. 
     * (positive values are rounded towards zero and negative values are rounded away from 0). 
     */
    function conservativePreciseDiv(int256 a, int256 b) internal pure returns (int256) {
        return divDown(a.mul(PRECISE_UNIT_INT), b);
    }

    /**
    * @dev Performs the power on a specified value, reverts on overflow.
    */
    function safePower(
        uint256 a,
        uint256 pow
    )
        internal
        pure
        returns (uint256)
    {
        require(a > 0, "Value must be positive");

        uint256 result = 1;
        for (uint256 i = 0; i < pow; i++){
            uint256 previousResult = result;

            // Using safemath multiplication prevents overflows
            result = previousResult.mul(a);
        }

        return result;
    }
}
// Dependency file: contracts/protocol/lib/Position.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

// pragma solidity 0.6.10;
// pragma experimental "ABIEncoderV2";

// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
// import { SafeCast } from "@openzeppelin/contracts/utils/SafeCast.sol";
// import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
// import { SignedSafeMath } from "@openzeppelin/contracts/math/SignedSafeMath.sol";

// import { ISetToken } from "../../interfaces/ISetToken.sol";
// import { PreciseUnitMath } from "../../lib/PreciseUnitMath.sol";

/**
 * @title Position
 * @author Set Protocol
 *
 * Collection of helper functions for handling and updating SetToken Positions
 */
library Position {
    using SafeCast for uint256;
    using SafeMath for uint256;
    using SafeCast for int256;
    using SignedSafeMath for int256;
    using PreciseUnitMath for uint256;

    /* ============ Helper ============ */

    /**
     * Returns whether the SetToken has a default position for a given component (if the real unit is > 0)
     */
    function hasDefaultPosition(ISetToken _setToken, address _component) internal view returns(bool) {
        return _setToken.getDefaultPositionRealUnit(_component) > 0;
    }

    /**
     * Returns whether the SetToken has an external position for a given component (if # of position modules is > 0)
     */
    function hasExternalPosition(ISetToken _setToken, address _component) internal view returns(bool) {
        return _setToken.getExternalPositionModules(_component).length > 0;
    }
    
    /**
     * Returns whether the SetToken component default position real unit is greater than or equal to units passed in.
     */
    function hasSufficientDefaultUnits(ISetToken _setToken, address _component, uint256 _unit) internal view returns(bool) {
        return _setToken.getDefaultPositionRealUnit(_component) >= _unit.toInt256();
    }

    /**
     * Returns whether the SetToken component external position is greater than or equal to the real units passed in.
     */
    function hasSufficientExternalUnits(
        ISetToken _setToken,
        address _component,
        address _positionModule,
        uint256 _unit
    )
        internal
        view
        returns(bool)
    {
       return _setToken.getExternalPositionRealUnit(_component, _positionModule) >= _unit.toInt256();    
    }

    /**
     * If the position does not exist, create a new Position and add to the SetToken. If it already exists,
     * then set the position units. If the new units is 0, remove the position. Handles adding/removing of 
     * components where needed (in light of potential external positions).
     *
     * @param _setToken           Address of SetToken being modified
     * @param _component          Address of the component
     * @param _newUnit            Quantity of Position units - must be >= 0
     */
    function editDefaultPosition(ISetToken _setToken, address _component, uint256 _newUnit) internal {
        bool isPositionFound = hasDefaultPosition(_setToken, _component);
        if (!isPositionFound && _newUnit > 0) {
            // If there is no Default Position and no External Modules, then component does not exist
            if (!hasExternalPosition(_setToken, _component)) {
                _setToken.addComponent(_component);
            }
        } else if (isPositionFound && _newUnit == 0) {
            // If there is a Default Position and no external positions, remove the component
            if (!hasExternalPosition(_setToken, _component)) {
                _setToken.removeComponent(_component);
            }
        }

        _setToken.editDefaultPositionUnit(_component, _newUnit.toInt256());
    }

    /**
     * Update an external position and remove and external positions or components if necessary. The logic flows as follows:
     * 1) If component is not already added then add component and external position. 
     * 2) If component is added but no existing external position using the passed module exists then add the external position.
     * 3) If the existing position is being added to then just update the unit
     * 4) If the position is being closed and no other external positions or default positions are associated with the component
     *    then untrack the component and remove external position.
     * 5) If the position is being closed and  other existing positions still exist for the component then just remove the
     *    external position.
     *
     * @param _setToken         SetToken being updated
     * @param _component        Component position being updated
     * @param _module           Module external position is associated with
     * @param _newUnit          Position units of new external position
     * @param _data             Arbitrary data associated with the position
     */
    function editExternalPosition(
        ISetToken _setToken,
        address _component,
        address _module,
        int256 _newUnit,
        bytes memory _data
    )
        internal
    {
        if (!_setToken.isComponent(_component)) {
            _setToken.addComponent(_component);
            addExternalPosition(_setToken, _component, _module, _newUnit, _data);
        } else if (!_setToken.isExternalPositionModule(_component, _module)) {
            addExternalPosition(_setToken, _component, _module, _newUnit, _data);
        } else if (_newUnit != 0) {
            _setToken.editExternalPositionUnit(_component, _module, _newUnit);
        } else {
            // If no default or external position remaining then remove component from components array
            if (_setToken.getDefaultPositionRealUnit(_component) == 0 && _setToken.getExternalPositionModules(_component).length == 1) {
                _setToken.removeComponent(_component);
            }
            _setToken.removeExternalPositionModule(_component, _module);
        }
    }

    /**
     * Add a new external position from a previously untracked module.
     *
     * @param _setToken         SetToken being updated
     * @param _component        Component position being updated
     * @param _module           Module external position is associated with
     * @param _newUnit          Position units of new external position
     * @param _data             Arbitrary data associated with the position
     */
    function addExternalPosition(
        ISetToken _setToken,
        address _component,
        address _module,
        int256 _newUnit,
        bytes memory _data
    )
        internal
    {
        _setToken.addExternalPositionModule(_component, _module);
        _setToken.editExternalPositionUnit(_component, _module, _newUnit);
        _setToken.editExternalPositionData(_component, _module, _data);
    }

    /**
     * Get total notional amount of Default position
     *
     * @param _setTokenSupply     Supply of SetToken in precise units (10^18)
     * @param _positionUnit       Quantity of Position units
     *
     * @return                    Total notional amount of units
     */
    function getDefaultTotalNotional(uint256 _setTokenSupply, uint256 _positionUnit) internal pure returns (uint256) {
        return _setTokenSupply.preciseMul(_positionUnit);
    }

    /**
     * Get position unit from total notional amount
     *
     * @param _setTokenSupply     Supply of SetToken in precise units (10^18)
     * @param _totalNotional      Total notional amount of component prior to
     * @return                    Default position unit
     */
    function getDefaultPositionUnit(uint256 _setTokenSupply, uint256 _totalNotional) internal pure returns (uint256) {
        return _totalNotional.preciseDiv(_setTokenSupply);
    }

    /**
     * Get the total tracked balance - total supply * position unit
     *
     * @param _setToken           Address of the SetToken
     * @param _component          Address of the component
     * @return                    Notional tracked balance
     */
    function getDefaultTrackedBalance(ISetToken _setToken, address _component) internal view returns(uint256) {
        int256 positionUnit = _setToken.getDefaultPositionRealUnit(_component); 
        return _setToken.totalSupply().preciseMul(positionUnit.toUint256());
    }

    /**
     * Calculates the new default position unit and performs the edit with the new unit
     *
     * @param _setToken                 Address of the SetToken
     * @param _component                Address of the component
     * @param _setTotalSupply           Current SetToken supply
     * @param _componentPreviousBalance Pre-action component balance
     * @return                          Current component balance
     * @return                          Previous position unit
     * @return                          New position unit
     */
    function calculateAndEditDefaultPosition(
        ISetToken _setToken,
        address _component,
        uint256 _setTotalSupply,
        uint256 _componentPreviousBalance
    )
        internal
        returns(uint256, uint256, uint256)
    {
        uint256 currentBalance = IERC20(_component).balanceOf(address(_setToken));
        uint256 positionUnit = _setToken.getDefaultPositionRealUnit(_component).toUint256();

        uint256 newTokenUnit = calculateDefaultEditPositionUnit(
            _setTotalSupply,
            _componentPreviousBalance,
            currentBalance,
            positionUnit
        );

        editDefaultPosition(_setToken, _component, newTokenUnit);

        return (currentBalance, positionUnit, newTokenUnit);
    }

    /**
     * Calculate the new position unit given total notional values pre and post executing an action that changes SetToken state
     * The intention is to make updates to the units without accidentally picking up airdropped assets as well.
     *
     * @param _setTokenSupply     Supply of SetToken in precise units (10^18)
     * @param _preTotalNotional   Total notional amount of component prior to executing action
     * @param _postTotalNotional  Total notional amount of component after the executing action
     * @param _prePositionUnit    Position unit of SetToken prior to executing action
     * @return                    New position unit
     */
    function calculateDefaultEditPositionUnit(
        uint256 _setTokenSupply,
        uint256 _preTotalNotional,
        uint256 _postTotalNotional,
        uint256 _prePositionUnit
    )
        internal
        pure
        returns (uint256)
    {
        // If pre action total notional amount is greater then subtract post action total notional and calculate new position units
        if (_preTotalNotional >= _postTotalNotional) {
            uint256 unitsToSub = _preTotalNotional.sub(_postTotalNotional).preciseDivCeil(_setTokenSupply);
            return _prePositionUnit.sub(unitsToSub);
        } else {
            // Else subtract post action total notional from pre action total notional and calculate new position units
            uint256 unitsToAdd = _postTotalNotional.sub(_preTotalNotional).preciseDiv(_setTokenSupply);
            return _prePositionUnit.add(unitsToAdd);
        }
    }
}

// Dependency file: contracts/protocol/lib/ModuleBase.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

// pragma solidity 0.6.10;

// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";

// import { ExplicitERC20 } from "../../lib/ExplicitERC20.sol";
// import { IController } from "../../interfaces/IController.sol";
// import { IModule } from "../../interfaces/IModule.sol";
// import { ISetToken } from "../../interfaces/ISetToken.sol";
// import { Invoke } from "./Invoke.sol";
// import { PreciseUnitMath } from "../../lib/PreciseUnitMath.sol";
// import { ResourceIdentifier } from "./ResourceIdentifier.sol";

/**
 * @title ModuleBase
 * @author Set Protocol
 *
 * Abstract class that houses common Module-related state and functions.
 */
abstract contract ModuleBase is IModule {
    using PreciseUnitMath for uint256;
    using Invoke for ISetToken;
    using ResourceIdentifier for IController;

    /* ============ State Variables ============ */

    // Address of the controller
    IController public controller;

    /* ============ Modifiers ============ */

    modifier onlyManagerAndValidSet(ISetToken _setToken) { 
        require(isSetManager(_setToken, msg.sender), "Must be the SetToken manager");
        require(isSetValidAndInitialized(_setToken), "Must be a valid and initialized SetToken");
        _;
    }

    modifier onlySetManager(ISetToken _setToken, address _caller) {
        require(isSetManager(_setToken, _caller), "Must be the SetToken manager");
        _;
    }

    modifier onlyValidAndInitializedSet(ISetToken _setToken) {
        require(isSetValidAndInitialized(_setToken), "Must be a valid and initialized SetToken");
        _;
    }

    /**
     * Throws if the sender is not a SetToken's module or module not enabled
     */
    modifier onlyModule(ISetToken _setToken) {
        require(
            _setToken.moduleStates(msg.sender) == ISetToken.ModuleState.INITIALIZED,
            "Only the module can call"
        );

        require(
            controller.isModule(msg.sender),
            "Module must be enabled on controller"
        );
        _;
    }

    /**
     * Utilized during module initializations to check that the module is in pending state
     * and that the SetToken is valid
     */
    modifier onlyValidAndPendingSet(ISetToken _setToken) {
        require(controller.isSet(address(_setToken)), "Must be controller-enabled SetToken");
        require(isSetPendingInitialization(_setToken), "Must be pending initialization");        
        _;
    }

    /* ============ Constructor ============ */

    /**
     * Set state variables and map asset pairs to their oracles
     *
     * @param _controller             Address of controller contract
     */
    constructor(IController _controller) public {
        controller = _controller;
    }

    /* ============ Internal Functions ============ */

    /**
     * Transfers tokens from an address (that has set allowance on the module).
     *
     * @param  _token          The address of the ERC20 token
     * @param  _from           The address to transfer from
     * @param  _to             The address to transfer to
     * @param  _quantity       The number of tokens to transfer
     */
    function transferFrom(IERC20 _token, address _from, address _to, uint256 _quantity) internal {
        ExplicitERC20.transferFrom(_token, _from, _to, _quantity);
    }

    /**
     * Gets the integration for the module with the passed in name. Validates that the address is not empty
     */
    function getAndValidateAdapter(string memory _integrationName) internal view returns(address) { 
        bytes32 integrationHash = getNameHash(_integrationName);
        return getAndValidateAdapterWithHash(integrationHash);
    }

    /**
     * Gets the integration for the module with the passed in hash. Validates that the address is not empty
     */
    function getAndValidateAdapterWithHash(bytes32 _integrationHash) internal view returns(address) { 
        address adapter = controller.getIntegrationRegistry().getIntegrationAdapterWithHash(
            address(this),
            _integrationHash
        );

        require(adapter != address(0), "Must be valid adapter"); 
        return adapter;
    }

    /**
     * Gets the total fee for this module of the passed in index (fee % * quantity)
     */
    function getModuleFee(uint256 _feeIndex, uint256 _quantity) internal view returns(uint256) {
        uint256 feePercentage = controller.getModuleFee(address(this), _feeIndex);
        return _quantity.preciseMul(feePercentage);
    }

    /**
     * Pays the _feeQuantity from the _setToken denominated in _token to the protocol fee recipient
     */
    function payProtocolFeeFromSetToken(ISetToken _setToken, address _token, uint256 _feeQuantity) internal {
        if (_feeQuantity > 0) {
            _setToken.strictInvokeTransfer(_token, controller.feeRecipient(), _feeQuantity); 
        }
    }

    /**
     * Returns true if the module is in process of initialization on the SetToken
     */
    function isSetPendingInitialization(ISetToken _setToken) internal view returns(bool) {
        return _setToken.isPendingModule(address(this));
    }

    /**
     * Returns true if the address is the SetToken's manager
     */
    function isSetManager(ISetToken _setToken, address _toCheck) internal view returns(bool) {
        return _setToken.manager() == _toCheck;
    }

    /**
     * Returns true if SetToken must be enabled on the controller 
     * and module is registered on the SetToken
     */
    function isSetValidAndInitialized(ISetToken _setToken) internal view returns(bool) {
        return controller.isSet(address(_setToken)) &&
            _setToken.isInitializedModule(address(this));
    }

    /**
     * Hashes the string and returns a bytes32 value
     */
    function getNameHash(string memory _name) internal pure returns(bytes32) {
        return keccak256(bytes(_name));
    }
}
// Dependency file: contracts/interfaces/external/IWETH.sol

/*
    Copyright 2018 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/


// Dependency file: @openzeppelin/contracts/token/ERC20/IERC20.sol

// pragma solidity ^0.6.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * // importANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// pragma solidity 0.6.10;

// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";

/**
 * @title IWETH
 * @author Set Protocol
 *
 * Interface for Wrapped Ether. This interface allows for interaction for wrapped ether's deposit and withdrawal
 * functionality.
 */
interface IWETH is IERC20{
    function deposit()
        external
        payable;

    function withdraw(
        uint256 wad
    )
        external;
}
// Dependency file: contracts/interfaces/ISetToken.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
// pragma solidity 0.6.10;
// pragma experimental "ABIEncoderV2";

// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";

/**
 * @title ISetToken
 * @author Set Protocol
 *
 * Interface for operating with SetTokens.
 */
interface ISetToken is IERC20 {

    /* ============ Enums ============ */

    enum ModuleState {
        NONE,
        PENDING,
        INITIALIZED
    }

    /* ============ Structs ============ */
    /**
     * The base definition of a SetToken Position
     *
     * @param component           Address of token in the Position
     * @param module              If not in default state, the address of associated module
     * @param unit                Each unit is the # of components per 10^18 of a SetToken
     * @param positionState       Position ENUM. Default is 0; External is 1
     * @param data                Arbitrary data
     */
    struct Position {
        address component;
        address module;
        int256 unit;
        uint8 positionState;
        bytes data;
    }

    /**
     * A struct that stores a component's cash position details and external positions
     * This data structure allows O(1) access to a component's cash position units and 
     * virtual units.
     *
     * @param virtualUnit               Virtual value of a component's DEFAULT position. Stored as virtual for efficiency
     *                                  updating all units at once via the position multiplier. Virtual units are achieved
     *                                  by dividing a "real" value by the "positionMultiplier"
     * @param componentIndex            
     * @param externalPositionModules   List of external modules attached to each external position. Each module
     *                                  maps to an external position
     * @param externalPositions         Mapping of module => ExternalPosition struct for a given component
     */
    struct ComponentPosition {
      int256 virtualUnit;
      address[] externalPositionModules;
      mapping(address => ExternalPosition) externalPositions;
    }

    /**
     * A struct that stores a component's external position details including virtual unit and any
     * auxiliary data.
     *
     * @param virtualUnit       Virtual value of a component's EXTERNAL position.
     * @param data              Arbitrary data
     */
    struct ExternalPosition {
      int256 virtualUnit;
      bytes data;
    }


    /* ============ Functions ============ */
    
    function addComponent(address _component) external;
    function removeComponent(address _component) external;
    function editDefaultPositionUnit(address _component, int256 _realUnit) external;
    function addExternalPositionModule(address _component, address _positionModule) external;
    function removeExternalPositionModule(address _component, address _positionModule) external;
    function editExternalPositionUnit(address _component, address _positionModule, int256 _realUnit) external;
    function editExternalPositionData(address _component, address _positionModule, bytes calldata _data) external;

    function invoke(address _target, uint256 _value, bytes calldata _data) external returns(bytes memory);

    function editPositionMultiplier(int256 _newMultiplier) external;

    function mint(address _account, uint256 _quantity) external;
    function burn(address _account, uint256 _quantity) external;

    function lock() external;
    function unlock() external;

    function addModule(address _module) external;
    function removeModule(address _module) external;
    function initializeModule() external;

    function setManager(address _manager) external;

    function manager() external view returns (address);
    function moduleStates(address _module) external view returns (ModuleState);
    function getModules() external view returns (address[] memory);
    
    function getDefaultPositionRealUnit(address _component) external view returns(int256);
    function getExternalPositionRealUnit(address _component, address _positionModule) external view returns(int256);
    function getComponents() external view returns(address[] memory);
    function getExternalPositionModules(address _component) external view returns(address[] memory);
    function getExternalPositionData(address _component, address _positionModule) external view returns(bytes memory);
    function isExternalPositionModule(address _component, address _module) external view returns(bool);
    function isComponent(address _component) external view returns(bool);
    
    function positionMultiplier() external view returns (int256);
    function getPositions() external view returns (Position[] memory);
    function getTotalComponentRealUnits(address _component) external view returns(int256);

    function isInitializedModule(address _module) external view returns(bool);
    function isPendingModule(address _module) external view returns(bool);
    function isLocked() external view returns (bool);
}
// Dependency file: contracts/protocol/lib/Invoke.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

// pragma solidity 0.6.10;

// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
// import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";

// import { ISetToken } from "../../interfaces/ISetToken.sol";


/**
 * @title Invoke
 * @author Set Protocol
 *
 * A collection of common utility functions for interacting with the SetToken's invoke function
 */
library Invoke {
    using SafeMath for uint256;

    /* ============ Internal ============ */

    /**
     * Instructs the SetToken to set approvals of the ERC20 token to a spender.
     *
     * @param _setToken        SetToken instance to invoke
     * @param _token           ERC20 token to approve
     * @param _spender         The account allowed to spend the SetToken's balance
     * @param _quantity        The quantity of allowance to allow
     */
    function invokeApprove(
        ISetToken _setToken,
        address _token,
        address _spender,
        uint256 _quantity
    )
        internal
    {
        bytes memory callData = abi.encodeWithSignature("approve(address,uint256)", _spender, _quantity);
        _setToken.invoke(_token, 0, callData);
    }

    /**
     * Instructs the SetToken to transfer the ERC20 token to a recipient.
     *
     * @param _setToken        SetToken instance to invoke
     * @param _token           ERC20 token to transfer
     * @param _to              The recipient account
     * @param _quantity        The quantity to transfer
     */
    function invokeTransfer(
        ISetToken _setToken,
        address _token,
        address _to,
        uint256 _quantity
    )
        internal
    {
        if (_quantity > 0) {
            bytes memory callData = abi.encodeWithSignature("transfer(address,uint256)", _to, _quantity);
            _setToken.invoke(_token, 0, callData);
        }
    }

    /**
     * Instructs the SetToken to transfer the ERC20 token to a recipient.
     * The new SetToken balance must equal the existing balance less the quantity transferred
     *
     * @param _setToken        SetToken instance to invoke
     * @param _token           ERC20 token to transfer
     * @param _to              The recipient account
     * @param _quantity        The quantity to transfer
     */
    function strictInvokeTransfer(
        ISetToken _setToken,
        address _token,
        address _to,
        uint256 _quantity
    )
        internal
    {
        if (_quantity > 0) {
            // Retrieve current balance of token for the SetToken
            uint256 existingBalance = IERC20(_token).balanceOf(address(_setToken));

            Invoke.invokeTransfer(_setToken, _token, _to, _quantity);

            // Get new balance of transferred token for SetToken
            uint256 newBalance = IERC20(_token).balanceOf(address(_setToken));

            // Verify only the transfer quantity is subtracted
            require(
                newBalance == existingBalance.sub(_quantity),
                "Invalid post transfer balance"
            );
        }
    }

    /**
     * Instructs the SetToken to unwrap the passed quantity of WETH
     *
     * @param _setToken        SetToken instance to invoke
     * @param _weth            WETH address
     * @param _quantity        The quantity to unwrap
     */
    function invokeUnwrapWETH(ISetToken _setToken, address _weth, uint256 _quantity) internal {
        bytes memory callData = abi.encodeWithSignature("withdraw(uint256)", _quantity);
        _setToken.invoke(_weth, 0, callData);
    }

    /**
     * Instructs the SetToken to wrap the passed quantity of ETH
     *
     * @param _setToken        SetToken instance to invoke
     * @param _weth            WETH address
     * @param _quantity        The quantity to unwrap
     */
    function invokeWrapWETH(ISetToken _setToken, address _weth, uint256 _quantity) internal {
        bytes memory callData = abi.encodeWithSignature("deposit()");
        _setToken.invoke(_weth, _quantity, callData);
    }
}
// Dependency file: contracts/interfaces/INAVIssuanceHook.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
// pragma solidity 0.6.10;

// import { ISetToken } from "./ISetToken.sol";

interface INAVIssuanceHook {
    function invokePreIssueHook(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _reserveAssetQuantity,
        address _sender,
        address _to
    )
        external;

    function invokePreRedeemHook(
        ISetToken _setToken,
        uint256 _redeemQuantity,
        address _sender,
        address _to
    )
        external;
}
// Dependency file: contracts/interfaces/IController.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
// pragma solidity 0.6.10;

interface IController {
    function addSet(address _setToken) external;
    function feeRecipient() external view returns(address);
    function getModuleFee(address _module, uint256 _feeType) external view returns(uint256);
    function isModule(address _module) external view returns(bool);
    function isSet(address _setToken) external view returns(bool);
    function isSystemContract(address _contractAddress) external view returns (bool);
    function resourceId(uint256 _id) external view returns(address);
}
// Dependency file: contracts/lib/AddressArrayUtils.sol

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

// pragma solidity 0.6.10;

/**
 * @title AddressArrayUtils
 * @author Set Protocol
 *
 * Utility functions to handle Address Arrays
 */
library AddressArrayUtils {

    /**
     * Finds the index of the first occurrence of the given element.
     * @param A The input array to search
     * @param a The value to find
     * @return Returns (index and isIn) for the first occurrence starting from index 0
     */
    function indexOf(address[] memory A, address a) internal pure returns (uint256, bool) {
        uint256 length = A.length;
        for (uint256 i = 0; i < length; i++) {
            if (A[i] == a) {
                return (i, true);
            }
        }
        return (uint256(-1), false);
    }

    /**
    * Returns true if the value is present in the list. Uses indexOf internally.
    * @param A The input array to search
    * @param a The value to find
    * @return Returns isIn for the first occurrence starting from index 0
    */
    function contains(address[] memory A, address a) internal pure returns (bool) {
        (, bool isIn) = indexOf(A, a);
        return isIn;
    }

    /**
    * Returns true if there are 2 elements that are the same in an array
    * @param A The input array to search
    * @return Returns boolean for the first occurrence of a duplicate
    */
    function hasDuplicate(address[] memory A) internal pure returns(bool) {
        require(A.length > 0, "A is empty");

        for (uint256 i = 0; i < A.length - 1; i++) {
            address current = A[i];
            for (uint256 j = i + 1; j < A.length; j++) {
                if (current == A[j]) {
                    return true;
                }
            }
        }
        return false;
    }

    /**
     * @param A The input array to search
     * @param a The address to remove     
     * @return Returns the array with the object removed.
     */
    function remove(address[] memory A, address a)
        internal
        pure
        returns (address[] memory)
    {
        (uint256 index, bool isIn) = indexOf(A, a);
        if (!isIn) {
            revert("Address not in array.");
        } else {
            (address[] memory _A,) = pop(A, index);
            return _A;
        }
    }

    /**
    * Removes specified index from array
    * @param A The input array to search
    * @param index The index to remove
    * @return Returns the new array and the removed entry
    */
    function pop(address[] memory A, uint256 index)
        internal
        pure
        returns (address[] memory, address)
    {
        uint256 length = A.length;
        require(index < A.length, "Index must be < A length");
        address[] memory newAddresses = new address[](length - 1);
        for (uint256 i = 0; i < index; i++) {
            newAddresses[i] = A[i];
        }
        for (uint256 j = index + 1; j < length; j++) {
            newAddresses[j - 1] = A[j];
        }
        return (newAddresses, A[index]);
    }
}
// Dependency file: @openzeppelin/contracts/math/SignedSafeMath.sol

// pragma solidity ^0.6.0;

/**
 * @title SignedSafeMath
 * @dev Signed math operations with safety checks that revert on error.
 */
library SignedSafeMath {
    int256 constant private _INT256_MIN = -2**255;

        /**
     * @dev Returns the multiplication of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(int256 a, int256 b) internal pure returns (int256) {
        // 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;
        }

        require(!(a == -1 && b == _INT256_MIN), "SignedSafeMath: multiplication overflow");

        int256 c = a * b;
        require(c / a == b, "SignedSafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two signed 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(int256 a, int256 b) internal pure returns (int256) {
        require(b != 0, "SignedSafeMath: division by zero");
        require(!(b == -1 && a == _INT256_MIN), "SignedSafeMath: division overflow");

        int256 c = a / b;

        return c;
    }

    /**
     * @dev Returns the subtraction of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a - b;
        require((b >= 0 && c <= a) || (b < 0 && c > a), "SignedSafeMath: subtraction overflow");

        return c;
    }

    /**
     * @dev Returns the addition of two signed integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(int256 a, int256 b) internal pure returns (int256) {
        int256 c = a + b;
        require((b >= 0 && c >= a) || (b < 0 && c < a), "SignedSafeMath: addition overflow");

        return c;
    }
}

// Dependency file: @openzeppelin/contracts/math/SafeMath.sol

// pragma solidity ^0.6.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        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;
    }
}

// Dependency file: @openzeppelin/contracts/utils/SafeCast.sol

// pragma solidity ^0.6.0;


/**
 * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
 * checks.
 *
 * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
 * easily result in undesired exploitation or bugs, since developers usually
 * assume that overflows raise errors. `SafeCast` restores this intuition by
 * reverting the transaction when such 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.
 *
 * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
 * all math on `uint256` and `int256` and then downcasting.
 */
library SafeCast {

    /**
     * @dev Returns the downcasted uint128 from uint256, reverting on
     * overflow (when the input is greater than largest uint128).
     *
     * Counterpart to Solidity's `uint128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     */
    function toUint128(uint256 value) internal pure returns (uint128) {
        require(value < 2**128, "SafeCast: value doesn\'t fit in 128 bits");
        return uint128(value);
    }

    /**
     * @dev Returns the downcasted uint64 from uint256, reverting on
     * overflow (when the input is greater than largest uint64).
     *
     * Counterpart to Solidity's `uint64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     */
    function toUint64(uint256 value) internal pure returns (uint64) {
        require(value < 2**64, "SafeCast: value doesn\'t fit in 64 bits");
        return uint64(value);
    }

    /**
     * @dev Returns the downcasted uint32 from uint256, reverting on
     * overflow (when the input is greater than largest uint32).
     *
     * Counterpart to Solidity's `uint32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     */
    function toUint32(uint256 value) internal pure returns (uint32) {
        require(value < 2**32, "SafeCast: value doesn\'t fit in 32 bits");
        return uint32(value);
    }

    /**
     * @dev Returns the downcasted uint16 from uint256, reverting on
     * overflow (when the input is greater than largest uint16).
     *
     * Counterpart to Solidity's `uint16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     */
    function toUint16(uint256 value) internal pure returns (uint16) {
        require(value < 2**16, "SafeCast: value doesn\'t fit in 16 bits");
        return uint16(value);
    }

    /**
     * @dev Returns the downcasted uint8 from uint256, reverting on
     * overflow (when the input is greater than largest uint8).
     *
     * Counterpart to Solidity's `uint8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits.
     */
    function toUint8(uint256 value) internal pure returns (uint8) {
        require(value < 2**8, "SafeCast: value doesn\'t fit in 8 bits");
        return uint8(value);
    }

    /**
     * @dev Converts a signed int256 into an unsigned uint256.
     *
     * Requirements:
     *
     * - input must be greater than or equal to 0.
     */
    function toUint256(int256 value) internal pure returns (uint256) {
        require(value >= 0, "SafeCast: value must be positive");
        return uint256(value);
    }

    /**
     * @dev Returns the downcasted int128 from int256, reverting on
     * overflow (when the input is less than smallest int128 or
     * greater than largest int128).
     *
     * Counterpart to Solidity's `int128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v3.1._
     */
    function toInt128(int256 value) internal pure returns (int128) {
        require(value >= -2**127 && value < 2**127, "SafeCast: value doesn\'t fit in 128 bits");
        return int128(value);
    }

    /**
     * @dev Returns the downcasted int64 from int256, reverting on
     * overflow (when the input is less than smallest int64 or
     * greater than largest int64).
     *
     * Counterpart to Solidity's `int64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v3.1._
     */
    function toInt64(int256 value) internal pure returns (int64) {
        require(value >= -2**63 && value < 2**63, "SafeCast: value doesn\'t fit in 64 bits");
        return int64(value);
    }

    /**
     * @dev Returns the downcasted int32 from int256, reverting on
     * overflow (when the input is less than smallest int32 or
     * greater than largest int32).
     *
     * Counterpart to Solidity's `int32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v3.1._
     */
    function toInt32(int256 value) internal pure returns (int32) {
        require(value >= -2**31 && value < 2**31, "SafeCast: value doesn\'t fit in 32 bits");
        return int32(value);
    }

    /**
     * @dev Returns the downcasted int16 from int256, reverting on
     * overflow (when the input is less than smallest int16 or
     * greater than largest int16).
     *
     * Counterpart to Solidity's `int16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v3.1._
     */
    function toInt16(int256 value) internal pure returns (int16) {
        require(value >= -2**15 && value < 2**15, "SafeCast: value doesn\'t fit in 16 bits");
        return int16(value);
    }

    /**
     * @dev Returns the downcasted int8 from int256, reverting on
     * overflow (when the input is less than smallest int8 or
     * greater than largest int8).
     *
     * Counterpart to Solidity's `int8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits.
     *
     * _Available since v3.1._
     */
    function toInt8(int256 value) internal pure returns (int8) {
        require(value >= -2**7 && value < 2**7, "SafeCast: value doesn\'t fit in 8 bits");
        return int8(value);
    }

    /**
     * @dev Converts an unsigned uint256 into a signed int256.
     *
     * Requirements:
     *
     * - input must be less than or equal to maxInt256.
     */
    function toInt256(uint256 value) internal pure returns (int256) {
        require(value < 2**255, "SafeCast: value doesn't fit in an int256");
        return int256(value);
    }
}

// Dependency file: @openzeppelin/contracts/utils/ReentrancyGuard.sol

// pragma solidity ^0.6.0;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    constructor () internal {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }
}

// Dependency file: @openzeppelin/contracts/token/ERC20/ERC20.sol

// pragma solidity ^0.6.0;

// import "../../GSN/Context.sol";
// import "./IERC20.sol";
// import "../../math/SafeMath.sol";
// import "../../utils/Address.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {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 is internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    function _approve(address owner, address spender, uint256 amount) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Sets {decimals} to a value other than the default one of 18.
     *
     * WARNING: This function should only be called from the constructor. Most
     * applications that interact with token contracts will not expect
     * {decimals} to ever change, and may work incorrectly if it does.
     */
    function _setupDecimals(uint8 decimals_) internal {
        _decimals = decimals_;
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be to transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

/*
    Copyright 2020 Set Labs Inc.

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

pragma solidity 0.6.10;
pragma experimental "ABIEncoderV2";

// import { ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
// import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
// import { ReentrancyGuard } from "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
// import { SafeCast } from "@openzeppelin/contracts/utils/SafeCast.sol";
// import { SafeMath } from "@openzeppelin/contracts/math/SafeMath.sol";
// import { SignedSafeMath } from "@openzeppelin/contracts/math/SignedSafeMath.sol";

// import { AddressArrayUtils } from "../../lib/AddressArrayUtils.sol";
// import { IController } from "../../interfaces/IController.sol";
// import { INAVIssuanceHook } from "../../interfaces/INAVIssuanceHook.sol";
// import { Invoke } from "../lib/Invoke.sol";
// import { ISetToken } from "../../interfaces/ISetToken.sol";
// import { IWETH } from "../../interfaces/external/IWETH.sol";
// import { ModuleBase } from "../lib/ModuleBase.sol";
// import { Position } from "../lib/Position.sol";
// import { PreciseUnitMath } from "../../lib/PreciseUnitMath.sol";
// import { ResourceIdentifier } from "../lib/ResourceIdentifier.sol";


/**
 * @title NavIssuanceModule
 * @author Set Protocol
 *
 * Module that enables issuance and redemption with any valid ERC20 token or ETH if allowed by the manager. Sender receives
 * a proportional amount of SetTokens on issuance or ERC20 token on redemption based on the calculated net asset value using
 * oracle prices. Manager is able to enforce a premium / discount on issuance / redemption to avoid arbitrage and front
 * running when relying on oracle prices. Managers can charge a fee (denominated in reserve asset).
 */
contract NavIssuanceModule is ModuleBase, ReentrancyGuard {
    using AddressArrayUtils for address[];
    using Invoke for ISetToken;
    using Position for ISetToken;
    using PreciseUnitMath for uint256;
    using PreciseUnitMath for int256;
    using ResourceIdentifier for IController;
    using SafeMath for uint256;
    using SafeCast for int256;
    using SafeCast for uint256;
    using SignedSafeMath for int256;

    /* ============ Events ============ */

    event SetTokenNAVIssued(
        ISetToken indexed _setToken,
        address _issuer,
        address _to,
        address _reserveAsset,
        address _hookContract,
        uint256 _setTokenQuantity,
        uint256 _managerFee,
        uint256 _premium
    );

    event SetTokenNAVRedeemed(
        ISetToken indexed _setToken,
        address _redeemer,
        address _to,
        address _reserveAsset,
        address _hookContract,
        uint256 _setTokenQuantity,
        uint256 _managerFee,
        uint256 _premium
    );

    event ReserveAssetAdded(
        ISetToken indexed _setToken,
        address _newReserveAsset
    );

    event ReserveAssetRemoved(
        ISetToken indexed _setToken,
        address _removedReserveAsset
    );

    event PremiumEdited(
        ISetToken indexed _setToken,
        uint256 _newPremium
    );

    event ManagerFeeEdited(
        ISetToken indexed _setToken,
        uint256 _newManagerFee,
        uint256 _index
    );

    event FeeRecipientEdited(
        ISetToken indexed _setToken,
        address _feeRecipient
    );

    /* ============ Structs ============ */

    struct NAVIssuanceSettings {
        INAVIssuanceHook managerIssuanceHook;      // Issuance hook configurations
        INAVIssuanceHook managerRedemptionHook;    // Redemption hook configurations
        address[] reserveAssets;                       // Allowed reserve assets - Must have a price enabled with the price oracle
        address feeRecipient;                          // Manager fee recipient
        uint256[2] managerFees;                        // Manager fees. 0 index is issue and 1 index is redeem fee (0.01% = 1e14, 1% = 1e16)
        uint256 maxManagerFee;                         // Maximum fee manager is allowed to set for issue and redeem
        uint256 premiumPercentage;                     // Premium percentage (0.01% = 1e14, 1% = 1e16). This premium is a buffer around oracle
                                                       // prices paid by user to the SetToken, which prevents arbitrage and oracle front running
        uint256 maxPremiumPercentage;                  // Maximum premium percentage manager is allowed to set (configured by manager)
        uint256 minSetTokenSupply;                     // Minimum SetToken supply required for issuance and redemption 
                                                       // to prevent dramatic inflationary changes to the SetToken's position multiplier
    }

    struct ActionInfo {
        uint256 preFeeReserveQuantity;                 // Reserve value before fees; During issuance, represents raw quantity
                                                       // During redeem, represents post-premium value
        uint256 protocolFees;                          // Total protocol fees (direct + manager revenue share)
        uint256 managerFee;                            // Total manager fee paid in reserve asset
        uint256 netFlowQuantity;                       // When issuing, quantity of reserve asset sent to SetToken
                                                       // When redeeming, quantity of reserve asset sent to redeemer
        uint256 setTokenQuantity;                      // When issuing, quantity of SetTokens minted to mintee
                                                       // When redeeming, quantity of SetToken redeemed
        uint256 previousSetTokenSupply;                // SetToken supply prior to issue/redeem action
        uint256 newSetTokenSupply;                     // SetToken supply after issue/redeem action
        int256 newPositionMultiplier;                  // SetToken position multiplier after issue/redeem
        uint256 newReservePositionUnit;                // SetToken reserve asset position unit after issue/redeem
    }

    /* ============ State Variables ============ */

    // Wrapped ETH address
    IWETH public immutable weth;

    // Mapping of SetToken to NAV issuance settings struct
    mapping(ISetToken => NAVIssuanceSettings) public navIssuanceSettings;
    
    // Mapping to efficiently check a SetToken's reserve asset validity
    // SetToken => reserveAsset => isReserveAsset
    mapping(ISetToken => mapping(address => bool)) public isReserveAsset;

    /* ============ Constants ============ */

    // 0 index stores the manager fee in managerFees array, percentage charged on issue (denominated in reserve asset)
    uint256 constant internal MANAGER_ISSUE_FEE_INDEX = 0;

    // 1 index stores the manager fee percentage in managerFees array, charged on redeem
    uint256 constant internal MANAGER_REDEEM_FEE_INDEX = 1;

    // 0 index stores the manager revenue share protocol fee % on the controller, charged in the issuance function
    uint256 constant internal PROTOCOL_ISSUE_MANAGER_REVENUE_SHARE_FEE_INDEX = 0;

    // 1 index stores the manager revenue share protocol fee % on the controller, charged in the redeem function
    uint256 constant internal PROTOCOL_REDEEM_MANAGER_REVENUE_SHARE_FEE_INDEX = 1;

    // 2 index stores the direct protocol fee % on the controller, charged in the issuance function
    uint256 constant internal PROTOCOL_ISSUE_DIRECT_FEE_INDEX = 2;

    // 3 index stores the direct protocol fee % on the controller, charged in the redeem function
    uint256 constant internal PROTOCOL_REDEEM_DIRECT_FEE_INDEX = 3;

    /* ============ Constructor ============ */

    /**
     * @param _controller               Address of controller contract
     * @param _weth                     Address of wrapped eth
     */
    constructor(IController _controller, IWETH _weth) public ModuleBase(_controller) {
        weth = _weth;
    }

    /* ============ External Functions ============ */
    
    /**
     * Deposits the allowed reserve asset into the SetToken and mints the appropriate % of Net Asset Value of the SetToken
     * to the specified _to address.
     *
     * @param _setToken                     Instance of the SetToken contract
     * @param _reserveAsset                 Address of the reserve asset to issue with
     * @param _reserveAssetQuantity         Quantity of the reserve asset to issue with
     * @param _minSetTokenReceiveQuantity   Min quantity of SetToken to receive after issuance
     * @param _to                           Address to mint SetToken to
     */
    function issue(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _reserveAssetQuantity,
        uint256 _minSetTokenReceiveQuantity,
        address _to
    ) 
        external
        nonReentrant
        onlyValidAndInitializedSet(_setToken)
    {
        _validateCommon(_setToken, _reserveAsset, _reserveAssetQuantity);
        
        _callPreIssueHooks(_setToken, _reserveAsset, _reserveAssetQuantity, msg.sender, _to);

        ActionInfo memory issueInfo = _createIssuanceInfo(_setToken, _reserveAsset, _reserveAssetQuantity);

        _validateIssuanceInfo(_setToken, _minSetTokenReceiveQuantity, issueInfo);

        _transferCollateralAndHandleFees(_setToken, IERC20(_reserveAsset), issueInfo);

        _handleIssueStateUpdates(_setToken, _reserveAsset, _to, issueInfo);
    }

    /**
     * Wraps ETH and deposits WETH if allowed into the SetToken and mints the appropriate % of Net Asset Value of the SetToken
     * to the specified _to address.
     *
     * @param _setToken                     Instance of the SetToken contract
     * @param _minSetTokenReceiveQuantity   Min quantity of SetToken to receive after issuance
     * @param _to                           Address to mint SetToken to
     */
    function issueWithEther(
        ISetToken _setToken,
        uint256 _minSetTokenReceiveQuantity,
        address _to
    ) 
        external
        payable
        nonReentrant
        onlyValidAndInitializedSet(_setToken)
    {
        weth.deposit{ value: msg.value }();

        _validateCommon(_setToken, address(weth), msg.value);
        
        _callPreIssueHooks(_setToken, address(weth), msg.value, msg.sender, _to);

        ActionInfo memory issueInfo = _createIssuanceInfo(_setToken, address(weth), msg.value);

        _validateIssuanceInfo(_setToken, _minSetTokenReceiveQuantity, issueInfo);

        _transferWETHAndHandleFees(_setToken, issueInfo);

        _handleIssueStateUpdates(_setToken, address(weth), _to, issueInfo);
    }

    /**
     * Redeems a SetToken into a valid reserve asset representing the appropriate % of Net Asset Value of the SetToken
     * to the specified _to address. Only valid if there are available reserve units on the SetToken.
     *
     * @param _setToken                     Instance of the SetToken contract
     * @param _reserveAsset                 Address of the reserve asset to redeem with
     * @param _setTokenQuantity             Quantity of SetTokens to redeem
     * @param _minReserveReceiveQuantity    Min quantity of reserve asset to receive
     * @param _to                           Address to redeem reserve asset to
     */
    function redeem(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _setTokenQuantity,
        uint256 _minReserveReceiveQuantity,
        address _to
    ) 
        external
        nonReentrant
        onlyValidAndInitializedSet(_setToken)
    {
        _validateCommon(_setToken, _reserveAsset, _setTokenQuantity);

        _callPreRedeemHooks(_setToken, _setTokenQuantity, msg.sender, _to);

        ActionInfo memory redeemInfo = _createRedemptionInfo(_setToken, _reserveAsset, _setTokenQuantity);

        _validateRedemptionInfo(_setToken, _minReserveReceiveQuantity, _setTokenQuantity, redeemInfo);

        _setToken.burn(msg.sender, _setTokenQuantity);

        // Instruct the SetToken to transfer the reserve asset back to the user
        _setToken.strictInvokeTransfer(
            _reserveAsset,
            _to,
            redeemInfo.netFlowQuantity
        );

        _handleRedemptionFees(_setToken, _reserveAsset, redeemInfo);

        _handleRedeemStateUpdates(_setToken, _reserveAsset, _to, redeemInfo);
    }

    /**
     * Redeems a SetToken into Ether (if WETH is valid) representing the appropriate % of Net Asset Value of the SetToken
     * to the specified _to address. Only valid if there are available WETH units on the SetToken.
     *
     * @param _setToken                     Instance of the SetToken contract
     * @param _setTokenQuantity             Quantity of SetTokens to redeem
     * @param _minReserveReceiveQuantity    Min quantity of reserve asset to receive
     * @param _to                           Address to redeem reserve asset to
     */
    function redeemIntoEther(
        ISetToken _setToken,
        uint256 _setTokenQuantity,
        uint256 _minReserveReceiveQuantity,
        address payable _to
    ) 
        external
        nonReentrant
        onlyValidAndInitializedSet(_setToken)
    {
        _validateCommon(_setToken, address(weth), _setTokenQuantity);

        _callPreRedeemHooks(_setToken, _setTokenQuantity, msg.sender, _to);

        ActionInfo memory redeemInfo = _createRedemptionInfo(_setToken, address(weth), _setTokenQuantity);

        _validateRedemptionInfo(_setToken, _minReserveReceiveQuantity, _setTokenQuantity, redeemInfo);

        _setToken.burn(msg.sender, _setTokenQuantity);

        // Instruct the SetToken to transfer WETH from SetToken to module
        _setToken.strictInvokeTransfer(
            address(weth),
            address(this),
            redeemInfo.netFlowQuantity
        );

        weth.withdraw(redeemInfo.netFlowQuantity);
        
        _to.transfer(redeemInfo.netFlowQuantity);

        _handleRedemptionFees(_setToken, address(weth), redeemInfo);

        _handleRedeemStateUpdates(_setToken, address(weth), _to, redeemInfo);
    }

    /**
     * SET MANAGER ONLY. Add an allowed reserve asset
     *
     * @param _setToken                     Instance of the SetToken
     * @param _reserveAsset                 Address of the reserve asset to add
     */
    function addReserveAsset(ISetToken _setToken, address _reserveAsset) external onlyManagerAndValidSet(_setToken) {
        require(!isReserveAsset[_setToken][_reserveAsset], "Reserve asset already exists");
        
        navIssuanceSettings[_setToken].reserveAssets.push(_reserveAsset);
        isReserveAsset[_setToken][_reserveAsset] = true;

        emit ReserveAssetAdded(_setToken, _reserveAsset);
    }

    /**
     * SET MANAGER ONLY. Remove a reserve asset
     *
     * @param _setToken                     Instance of the SetToken
     * @param _reserveAsset                 Address of the reserve asset to remove
     */
    function removeReserveAsset(ISetToken _setToken, address _reserveAsset) external onlyManagerAndValidSet(_setToken) {
        require(isReserveAsset[_setToken][_reserveAsset], "Reserve asset does not exist");

        navIssuanceSettings[_setToken].reserveAssets = navIssuanceSettings[_setToken].reserveAssets.remove(_reserveAsset);
        delete isReserveAsset[_setToken][_reserveAsset];

        emit ReserveAssetRemoved(_setToken, _reserveAsset);
    }

    /**
     * SET MANAGER ONLY. Edit the premium percentage
     *
     * @param _setToken                     Instance of the SetToken
     * @param _premiumPercentage            Premium percentage in 10e16 (e.g. 10e16 = 1%)
     */
    function editPremium(ISetToken _setToken, uint256 _premiumPercentage) external onlyManagerAndValidSet(_setToken) {
        require(_premiumPercentage <= navIssuanceSettings[_setToken].maxPremiumPercentage, "Premium must be less than maximum allowed");
        
        navIssuanceSettings[_setToken].premiumPercentage = _premiumPercentage;

        emit PremiumEdited(_setToken, _premiumPercentage);
    }

    /**
     * SET MANAGER ONLY. Edit manager fee
     *
     * @param _setToken                     Instance of the SetToken
     * @param _managerFeePercentage         Manager fee percentage in 10e16 (e.g. 10e16 = 1%)
     * @param _managerFeeIndex              Manager fee index. 0 index is issue fee, 1 index is redeem fee
     */
    function editManagerFee(
        ISetToken _setToken,
        uint256 _managerFeePercentage,
        uint256 _managerFeeIndex
    )
        external
        onlyManagerAndValidSet(_setToken)
    {
        require(_managerFeePercentage <= navIssuanceSettings[_setToken].maxManagerFee, "Manager fee must be less than maximum allowed");
        
        navIssuanceSettings[_setToken].managerFees[_managerFeeIndex] = _managerFeePercentage;

        emit ManagerFeeEdited(_setToken, _managerFeePercentage, _managerFeeIndex);
    }

    /**
     * SET MANAGER ONLY. Edit the manager fee recipient
     *
     * @param _setToken                     Instance of the SetToken
     * @param _managerFeeRecipient          Manager fee recipient
     */
    function editFeeRecipient(ISetToken _setToken, address _managerFeeRecipient) external onlyManagerAndValidSet(_setToken) {
        require(_managerFeeRecipient != address(0), "Fee recipient must not be 0 address");
        
        navIssuanceSettings[_setToken].feeRecipient = _managerFeeRecipient;

        emit FeeRecipientEdited(_setToken, _managerFeeRecipient);
    }

    /**
     * SET MANAGER ONLY. Initializes this module to the SetToken with hooks, allowed reserve assets,
     * fees and issuance premium. Only callable by the SetToken's manager. Hook addresses are optional.
     * Address(0) means that no hook will be called.
     *
     * @param _setToken                     Instance of the SetToken to issue
     * @param _navIssuanceSettings          NAVIssuanceSettings struct defining parameters
     */
    function initialize(
        ISetToken _setToken,
        NAVIssuanceSettings memory _navIssuanceSettings
    )
        external
        onlySetManager(_setToken, msg.sender)
        onlyValidAndPendingSet(_setToken)
    {
        require(_navIssuanceSettings.reserveAssets.length > 0, "Reserve assets must be greater than 0");
        require(_navIssuanceSettings.maxManagerFee < PreciseUnitMath.preciseUnit(), "Max manager fee must be less than 100%");
        require(_navIssuanceSettings.maxPremiumPercentage < PreciseUnitMath.preciseUnit(), "Max premium percentage must be less than 100%");
        require(_navIssuanceSettings.managerFees[0] <= _navIssuanceSettings.maxManagerFee, "Manager issue fee must be less than max");
        require(_navIssuanceSettings.managerFees[1] <= _navIssuanceSettings.maxManagerFee, "Manager redeem fee must be less than max");
        require(_navIssuanceSettings.premiumPercentage <= _navIssuanceSettings.maxPremiumPercentage, "Premium must be less than max");
        require(_navIssuanceSettings.feeRecipient != address(0), "Fee Recipient must be non-zero address.");
        // Initial mint of Set cannot use NAVIssuance since minSetTokenSupply must be > 0
        require(_navIssuanceSettings.minSetTokenSupply > 0, "Min SetToken supply must be greater than 0");

        for (uint256 i = 0; i < _navIssuanceSettings.reserveAssets.length; i++) {
            require(!isReserveAsset[_setToken][_navIssuanceSettings.reserveAssets[i]], "Reserve assets must be unique");
            isReserveAsset[_setToken][_navIssuanceSettings.reserveAssets[i]] = true;
        }

        navIssuanceSettings[_setToken] = _navIssuanceSettings;

        _setToken.initializeModule();
    }

    /**
     * Removes this module from the SetToken, via call by the SetToken. Issuance settings and
     * reserve asset states are deleted.
     */
    function removeModule() external override {
        ISetToken setToken = ISetToken(msg.sender);
        for (uint256 i = 0; i < navIssuanceSettings[setToken].reserveAssets.length; i++) {
            delete isReserveAsset[setToken][navIssuanceSettings[setToken].reserveAssets[i]];
        }
        
        delete navIssuanceSettings[setToken];
    }

    receive() external payable {}

    /* ============ External Getter Functions ============ */

    function getReserveAssets(ISetToken _setToken) external view returns (address[] memory) {
        return navIssuanceSettings[_setToken].reserveAssets;
    }

    function getIssuePremium(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _reserveAssetQuantity
    )
        external
        view
        returns (uint256)
    {
        return _getIssuePremium(_setToken, _reserveAsset, _reserveAssetQuantity);
    }

    function getRedeemPremium(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _setTokenQuantity
    )
        external
        view
        returns (uint256)
    {
        return _getRedeemPremium(_setToken, _reserveAsset, _setTokenQuantity);
    }

    function getManagerFee(ISetToken _setToken, uint256 _managerFeeIndex) external view returns (uint256) {
        return navIssuanceSettings[_setToken].managerFees[_managerFeeIndex];
    }

    /**
     * Get the expected SetTokens minted to recipient on issuance
     *
     * @param _setToken                     Instance of the SetToken
     * @param _reserveAsset                 Address of the reserve asset
     * @param _reserveAssetQuantity         Quantity of the reserve asset to issue with
     *
     * @return  uint256                     Expected SetTokens to be minted to recipient
     */
    function getExpectedSetTokenIssueQuantity(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _reserveAssetQuantity
    )
        external
        view
        returns (uint256)
    {
        (,, uint256 netReserveFlow) = _getFees(
            _setToken,
            _reserveAssetQuantity,
            PROTOCOL_ISSUE_MANAGER_REVENUE_SHARE_FEE_INDEX,
            PROTOCOL_ISSUE_DIRECT_FEE_INDEX,
            MANAGER_ISSUE_FEE_INDEX
        );

        uint256 setTotalSupply = _setToken.totalSupply();

        return _getSetTokenMintQuantity(
            _setToken,
            _reserveAsset,
            netReserveFlow,
            setTotalSupply
        );
    }

    /**
     * Get the expected reserve asset to be redeemed
     *
     * @param _setToken                     Instance of the SetToken
     * @param _reserveAsset                 Address of the reserve asset
     * @param _setTokenQuantity             Quantity of SetTokens to redeem
     *
     * @return  uint256                     Expected reserve asset quantity redeemed
     */
    function getExpectedReserveRedeemQuantity(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _setTokenQuantity
    )
        external
        view
        returns (uint256)
    {
        uint256 preFeeReserveQuantity = _getRedeemReserveQuantity(_setToken, _reserveAsset, _setTokenQuantity);

        (,, uint256 netReserveFlows) = _getFees(
            _setToken,
            preFeeReserveQuantity,
            PROTOCOL_REDEEM_MANAGER_REVENUE_SHARE_FEE_INDEX,
            PROTOCOL_REDEEM_DIRECT_FEE_INDEX,
            MANAGER_REDEEM_FEE_INDEX
        );

        return netReserveFlows;
    }

    /**
     * Checks if issue is valid
     *
     * @param _setToken                     Instance of the SetToken
     * @param _reserveAsset                 Address of the reserve asset
     * @param _reserveAssetQuantity         Quantity of the reserve asset to issue with
     *
     * @return  bool                        Returns true if issue is valid
     */
    function isIssueValid(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _reserveAssetQuantity
    )
        external
        view
        returns (bool)
    {
        uint256 setTotalSupply = _setToken.totalSupply();

    return _reserveAssetQuantity != 0
            && isReserveAsset[_setToken][_reserveAsset]
            && setTotalSupply >= navIssuanceSettings[_setToken].minSetTokenSupply;
    }

    /**
     * Checks if redeem is valid
     *
     * @param _setToken                     Instance of the SetToken
     * @param _reserveAsset                 Address of the reserve asset
     * @param _setTokenQuantity             Quantity of SetTokens to redeem
     *
     * @return  bool                        Returns true if redeem is valid
     */
    function isRedeemValid(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _setTokenQuantity
    )
        external
        view
        returns (bool)
    {
        uint256 setTotalSupply = _setToken.totalSupply();

        if (
            _setTokenQuantity == 0
            || !isReserveAsset[_setToken][_reserveAsset]
            || setTotalSupply < navIssuanceSettings[_setToken].minSetTokenSupply.add(_setTokenQuantity)
        ) {
            return false;
        } else {
            uint256 totalRedeemValue =_getRedeemReserveQuantity(_setToken, _reserveAsset, _setTokenQuantity);

            (,, uint256 expectedRedeemQuantity) = _getFees(
                _setToken,
                totalRedeemValue,
                PROTOCOL_REDEEM_MANAGER_REVENUE_SHARE_FEE_INDEX,
                PROTOCOL_REDEEM_DIRECT_FEE_INDEX,
                MANAGER_REDEEM_FEE_INDEX
            );

            uint256 existingUnit = _setToken.getDefaultPositionRealUnit(_reserveAsset).toUint256();

            return existingUnit.preciseMul(setTotalSupply) >= expectedRedeemQuantity;
        }
    }

    /* ============ Internal Functions ============ */

    function _validateCommon(ISetToken _setToken, address _reserveAsset, uint256 _quantity) internal view {
        require(_quantity > 0, "Quantity must be > 0");
        require(isReserveAsset[_setToken][_reserveAsset], "Must be valid reserve asset");
    }

    function _validateIssuanceInfo(ISetToken _setToken, uint256 _minSetTokenReceiveQuantity, ActionInfo memory _issueInfo) internal view {
        // Check that total supply is greater than min supply needed for issuance
        // Note: A min supply amount is needed to avoid division by 0 when SetToken supply is 0
        require(
            _issueInfo.previousSetTokenSupply >= navIssuanceSettings[_setToken].minSetTokenSupply,
            "Supply must be greater than minimum to enable issuance"
        );

        require(_issueInfo.setTokenQuantity >= _minSetTokenReceiveQuantity, "Must be greater than min SetToken");
    }

    function _validateRedemptionInfo(
        ISetToken _setToken,
        uint256 _minReserveReceiveQuantity,
        uint256 _setTokenQuantity,
        ActionInfo memory _redeemInfo
    )
        internal
        view
    {
        // Check that new supply is more than min supply needed for redemption
        // Note: A min supply amount is needed to avoid division by 0 when redeeming SetToken to 0
        require(
            _redeemInfo.newSetTokenSupply >= navIssuanceSettings[_setToken].minSetTokenSupply,
            "Supply must be greater than minimum to enable redemption"
        );

        require(_redeemInfo.netFlowQuantity >= _minReserveReceiveQuantity, "Must be greater than min receive reserve quantity");
    }

    function _createIssuanceInfo(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _reserveAssetQuantity
    )
        internal
        view
        returns (ActionInfo memory)
    {
        ActionInfo memory issueInfo;

        issueInfo.previousSetTokenSupply = _setToken.totalSupply();

        issueInfo.preFeeReserveQuantity = _reserveAssetQuantity;

        (issueInfo.protocolFees, issueInfo.managerFee, issueInfo.netFlowQuantity) = _getFees(
            _setToken,
            issueInfo.preFeeReserveQuantity,
            PROTOCOL_ISSUE_MANAGER_REVENUE_SHARE_FEE_INDEX,
            PROTOCOL_ISSUE_DIRECT_FEE_INDEX,
            MANAGER_ISSUE_FEE_INDEX
        );

        issueInfo.setTokenQuantity = _getSetTokenMintQuantity(
            _setToken,
            _reserveAsset,
            issueInfo.netFlowQuantity,
            issueInfo.previousSetTokenSupply
        );

        (issueInfo.newSetTokenSupply, issueInfo.newPositionMultiplier) = _getIssuePositionMultiplier(_setToken, issueInfo);

        issueInfo.newReservePositionUnit = _getIssuePositionUnit(_setToken, _reserveAsset, issueInfo);

        return issueInfo;
    }

    function _createRedemptionInfo(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _setTokenQuantity
    )
        internal
        view
        returns (ActionInfo memory)
    {
        ActionInfo memory redeemInfo;

        redeemInfo.setTokenQuantity = _setTokenQuantity;

        redeemInfo.preFeeReserveQuantity =_getRedeemReserveQuantity(_setToken, _reserveAsset, _setTokenQuantity);

        (redeemInfo.protocolFees, redeemInfo.managerFee, redeemInfo.netFlowQuantity) = _getFees(
            _setToken,
            redeemInfo.preFeeReserveQuantity,
            PROTOCOL_REDEEM_MANAGER_REVENUE_SHARE_FEE_INDEX,
            PROTOCOL_REDEEM_DIRECT_FEE_INDEX,
            MANAGER_REDEEM_FEE_INDEX
        );

        redeemInfo.previousSetTokenSupply = _setToken.totalSupply();

        (redeemInfo.newSetTokenSupply, redeemInfo.newPositionMultiplier) = _getRedeemPositionMultiplier(_setToken, _setTokenQuantity, redeemInfo);

        redeemInfo.newReservePositionUnit = _getRedeemPositionUnit(_setToken, _reserveAsset, redeemInfo);

        return redeemInfo;
    }

    /**
     * Transfer reserve asset from user to SetToken and fees from user to appropriate fee recipients
     */
    function _transferCollateralAndHandleFees(ISetToken _setToken, IERC20 _reserveAsset, ActionInfo memory _issueInfo) internal {
        transferFrom(_reserveAsset, msg.sender, address(_setToken), _issueInfo.netFlowQuantity);

        if (_issueInfo.protocolFees > 0) {
            transferFrom(_reserveAsset, msg.sender, controller.feeRecipient(), _issueInfo.protocolFees);
        }

        if (_issueInfo.managerFee > 0) {
            transferFrom(_reserveAsset, msg.sender, navIssuanceSettings[_setToken].feeRecipient, _issueInfo.managerFee);
        }
    }


    /**
      * Transfer WETH from module to SetToken and fees from module to appropriate fee recipients
     */
    function _transferWETHAndHandleFees(ISetToken _setToken, ActionInfo memory _issueInfo) internal {
        weth.transfer(address(_setToken), _issueInfo.netFlowQuantity);

        if (_issueInfo.protocolFees > 0) {
            weth.transfer(controller.feeRecipient(), _issueInfo.protocolFees);
        }

        if (_issueInfo.managerFee > 0) {
            weth.transfer(navIssuanceSettings[_setToken].feeRecipient, _issueInfo.managerFee);
        }
    }

    function _handleIssueStateUpdates(
        ISetToken _setToken,
        address _reserveAsset,
        address _to,
        ActionInfo memory _issueInfo
    ) 
        internal
    {
        _setToken.editPositionMultiplier(_issueInfo.newPositionMultiplier);

        _setToken.editDefaultPosition(_reserveAsset, _issueInfo.newReservePositionUnit);

        _setToken.mint(_to, _issueInfo.setTokenQuantity);

        emit SetTokenNAVIssued(
            _setToken,
            msg.sender,
            _to,
            _reserveAsset,
            address(navIssuanceSettings[_setToken].managerIssuanceHook),
            _issueInfo.setTokenQuantity,
            _issueInfo.managerFee,
            _issueInfo.protocolFees
        );        
    }

    function _handleRedeemStateUpdates(
        ISetToken _setToken,
        address _reserveAsset,
        address _to,
        ActionInfo memory _redeemInfo
    ) 
        internal
    {
        _setToken.editPositionMultiplier(_redeemInfo.newPositionMultiplier);

        _setToken.editDefaultPosition(_reserveAsset, _redeemInfo.newReservePositionUnit);

        emit SetTokenNAVRedeemed(
            _setToken,
            msg.sender,
            _to,
            _reserveAsset,
            address(navIssuanceSettings[_setToken].managerRedemptionHook),
            _redeemInfo.setTokenQuantity,
            _redeemInfo.managerFee,
            _redeemInfo.protocolFees
        );      
    }

    function _handleRedemptionFees(ISetToken _setToken, address _reserveAsset, ActionInfo memory _redeemInfo) internal {
        // Instruct the SetToken to transfer protocol fee to fee recipient if there is a fee
        payProtocolFeeFromSetToken(_setToken, _reserveAsset, _redeemInfo.protocolFees);

        // Instruct the SetToken to transfer manager fee to manager fee recipient if there is a fee
        if (_redeemInfo.managerFee > 0) {
            _setToken.strictInvokeTransfer(
                _reserveAsset,
                navIssuanceSettings[_setToken].feeRecipient,
                _redeemInfo.managerFee
            );
        }
    }

    /**
     * Returns the issue premium percentage. Virtual function that can be overridden in future versions of the module
     * and can contain arbitrary logic to calculate the issuance premium.
     */
    function _getIssuePremium(
        ISetToken _setToken,
        address /* _reserveAsset */,
        uint256 /* _reserveAssetQuantity */
    )
        virtual
        internal
        view
        returns (uint256)
    {
        return navIssuanceSettings[_setToken].premiumPercentage;
    }

    /**
     * Returns the redeem premium percentage. Virtual function that can be overridden in future versions of the module
     * and can contain arbitrary logic to calculate the redemption premium.
     */
    function _getRedeemPremium(
        ISetToken _setToken,
        address /* _reserveAsset */,
        uint256 /* _setTokenQuantity */
    )
        virtual
        internal
        view
        returns (uint256)
    {
        return navIssuanceSettings[_setToken].premiumPercentage;
    }

    /**
     * Returns the fees attributed to the manager and the protocol. The fees are calculated as follows:
     *
     * ManagerFee = (manager fee % - % to protocol) * reserveAssetQuantity
     * Protocol Fee = (% manager fee share + direct fee %) * reserveAssetQuantity
     *
     * @param _setToken                     Instance of the SetToken
     * @param _reserveAssetQuantity         Quantity of reserve asset to calculate fees from
     * @param _protocolManagerFeeIndex      Index to pull rev share NAV Issuance fee from the Controller
     * @param _protocolDirectFeeIndex       Index to pull direct NAV issuance fee from the Controller
     * @param _managerFeeIndex              Index from NAVIssuanceSettings (0 = issue fee, 1 = redeem fee)
     *
     * @return  uint256                     Fees paid to the protocol in reserve asset
     * @return  uint256                     Fees paid to the manager in reserve asset
     * @return  uint256                     Net reserve to user net of fees
     */
    function _getFees(
        ISetToken _setToken,
        uint256 _reserveAssetQuantity,
        uint256 _protocolManagerFeeIndex,
        uint256 _protocolDirectFeeIndex,
        uint256 _managerFeeIndex
    )
        internal
        view
        returns (uint256, uint256, uint256)
    {
        (uint256 protocolFeePercentage, uint256 managerFeePercentage) = _getProtocolAndManagerFeePercentages(
            _setToken,
            _protocolManagerFeeIndex,
            _protocolDirectFeeIndex,
            _managerFeeIndex
        );

        // Calculate total notional fees
        uint256 protocolFees = protocolFeePercentage.preciseMul(_reserveAssetQuantity);
        uint256 managerFee = managerFeePercentage.preciseMul(_reserveAssetQuantity);

        uint256 netReserveFlow = _reserveAssetQuantity.sub(protocolFees).sub(managerFee);

        return (protocolFees, managerFee, netReserveFlow);
    }

    function _getProtocolAndManagerFeePercentages(
        ISetToken _setToken,
        uint256 _protocolManagerFeeIndex,
        uint256 _protocolDirectFeeIndex,
        uint256 _managerFeeIndex
    )
        internal
        view
        returns(uint256, uint256)
    {
        // Get protocol fee percentages
        uint256 protocolDirectFeePercent = controller.getModuleFee(address(this), _protocolDirectFeeIndex);
        uint256 protocolManagerShareFeePercent = controller.getModuleFee(address(this), _protocolManagerFeeIndex);
        uint256 managerFeePercent = navIssuanceSettings[_setToken].managerFees[_managerFeeIndex];
        
        // Calculate revenue share split percentage
        uint256 protocolRevenueSharePercentage = protocolManagerShareFeePercent.preciseMul(managerFeePercent);
        uint256 managerRevenueSharePercentage = managerFeePercent.sub(protocolRevenueSharePercentage);
        uint256 totalProtocolFeePercentage = protocolRevenueSharePercentage.add(protocolDirectFeePercent);

        return (managerRevenueSharePercentage, totalProtocolFeePercentage);
    }

    function _getSetTokenMintQuantity(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _netReserveFlows,            // Value of reserve asset net of fees
        uint256 _setTotalSupply
    )
        internal
        view
        returns (uint256)
    {
        uint256 premiumPercentage = _getIssuePremium(_setToken, _reserveAsset, _netReserveFlows);
        uint256 premiumValue = _netReserveFlows.preciseMul(premiumPercentage);

        // Get valuation of the SetToken with the quote asset as the reserve asset. Returns value in precise units (1e18)
        // Reverts if price is not found
        uint256 setTokenValuation = controller.getSetValuer().calculateSetTokenValuation(_setToken, _reserveAsset);

        // Get reserve asset decimals
        uint256 reserveAssetDecimals = ERC20(_reserveAsset).decimals();
        uint256 normalizedTotalReserveQuantityNetFees = _netReserveFlows.preciseDiv(10 ** reserveAssetDecimals);
        uint256 normalizedTotalReserveQuantityNetFeesAndPremium = _netReserveFlows.sub(premiumValue).preciseDiv(10 ** reserveAssetDecimals);

        // Calculate SetTokens to mint to issuer
        uint256 denominator = _setTotalSupply.preciseMul(setTokenValuation).add(normalizedTotalReserveQuantityNetFees).sub(normalizedTotalReserveQuantityNetFeesAndPremium);
        return normalizedTotalReserveQuantityNetFeesAndPremium.preciseMul(_setTotalSupply).preciseDiv(denominator);
    }

    function _getRedeemReserveQuantity(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _setTokenQuantity
    )
        internal
        view
        returns (uint256)
    {
        // Get valuation of the SetToken with the quote asset as the reserve asset. Returns value in precise units (10e18)
        // Reverts if price is not found
        uint256 setTokenValuation = controller.getSetValuer().calculateSetTokenValuation(_setToken, _reserveAsset);

        uint256 totalRedeemValueInPreciseUnits = _setTokenQuantity.preciseMul(setTokenValuation);
        // Get reserve asset decimals
        uint256 reserveAssetDecimals = ERC20(_reserveAsset).decimals();
        uint256 prePremiumReserveQuantity = totalRedeemValueInPreciseUnits.preciseMul(10 ** reserveAssetDecimals);

        uint256 premiumPercentage = _getRedeemPremium(_setToken, _reserveAsset, _setTokenQuantity);
        uint256 premiumQuantity = prePremiumReserveQuantity.preciseMulCeil(premiumPercentage);

        return prePremiumReserveQuantity.sub(premiumQuantity);
    }

    /**
     * The new position multiplier is calculated as follows:
     * inflationPercentage = (newSupply - oldSupply) / newSupply
     * newMultiplier = (1 - inflationPercentage) * positionMultiplier
     */    
    function _getIssuePositionMultiplier(
        ISetToken _setToken,
        ActionInfo memory _issueInfo
    )
        internal
        view
        returns (uint256, int256)
    {
        // Calculate inflation and new position multiplier. Note: Round inflation up in order to round position multiplier down
        uint256 newTotalSupply = _issueInfo.setTokenQuantity.add(_issueInfo.previousSetTokenSupply);
        int256 newPositionMultiplier = _setToken.positionMultiplier()
            .mul(_issueInfo.previousSetTokenSupply.toInt256())
            .div(newTotalSupply.toInt256());

        return (newTotalSupply, newPositionMultiplier);
    }

    /**
     * Calculate deflation and new position multiplier. Note: Round deflation down in order to round position multiplier down
     * 
     * The new position multiplier is calculated as follows:
     * deflationPercentage = (oldSupply - newSupply) / newSupply
     * newMultiplier = (1 + deflationPercentage) * positionMultiplier
     */ 
    function _getRedeemPositionMultiplier(
        ISetToken _setToken,
        uint256 _setTokenQuantity,
        ActionInfo memory _redeemInfo
    )
        internal
        view
        returns (uint256, int256)
    {
        uint256 newTotalSupply = _redeemInfo.previousSetTokenSupply.sub(_setTokenQuantity);
        int256 newPositionMultiplier = _setToken.positionMultiplier()
            .mul(_redeemInfo.previousSetTokenSupply.toInt256())
            .div(newTotalSupply.toInt256());

        return (newTotalSupply, newPositionMultiplier);
    }

    /**
     * The new position reserve asset unit is calculated as follows:
     * totalReserve = (oldUnit * oldSetTokenSupply) + reserveQuantity
     * newUnit = totalReserve / newSetTokenSupply
     */ 
    function _getIssuePositionUnit(
        ISetToken _setToken,
        address _reserveAsset,
        ActionInfo memory _issueInfo
    )
        internal
        view
        returns (uint256)
    {
        uint256 existingUnit = _setToken.getDefaultPositionRealUnit(_reserveAsset).toUint256();
        uint256 totalReserve = existingUnit
            .preciseMul(_issueInfo.previousSetTokenSupply)
            .add(_issueInfo.netFlowQuantity);

        return totalReserve.preciseDiv(_issueInfo.newSetTokenSupply);
    }

    /**
     * The new position reserve asset unit is calculated as follows:
     * totalReserve = (oldUnit * oldSetTokenSupply) - reserveQuantityToSendOut
     * newUnit = totalReserve / newSetTokenSupply
     */ 
    function _getRedeemPositionUnit(
        ISetToken _setToken,
        address _reserveAsset,
        ActionInfo memory _redeemInfo
    )
        internal
        view
        returns (uint256)
    {
        uint256 existingUnit = _setToken.getDefaultPositionRealUnit(_reserveAsset).toUint256();
        uint256 totalExistingUnits = existingUnit.preciseMul(_redeemInfo.previousSetTokenSupply);

        uint256 outflow = _redeemInfo.netFlowQuantity.add(_redeemInfo.protocolFees).add(_redeemInfo.managerFee);

        // Require withdrawable quantity is greater than existing collateral
        require(totalExistingUnits >= outflow, "Must be greater than total available collateral");

        return totalExistingUnits.sub(outflow).preciseDiv(_redeemInfo.newSetTokenSupply);
    }

    /**
     * If a pre-issue hook has been configured, call the external-protocol contract. Pre-issue hook logic
     * can contain arbitrary logic including validations, external function calls, etc.
     */
    function _callPreIssueHooks(
        ISetToken _setToken,
        address _reserveAsset,
        uint256 _reserveAssetQuantity,
        address _caller,
        address _to
    )
        internal
    {
        INAVIssuanceHook preIssueHook = navIssuanceSettings[_setToken].managerIssuanceHook;
        if (address(preIssueHook) != address(0)) {
            preIssueHook.invokePreIssueHook(_setToken, _reserveAsset, _reserveAssetQuantity, _caller, _to);
        }
    }

    /**
     * If a pre-redeem hook has been configured, call the external-protocol contract.
     */
    function _callPreRedeemHooks(ISetToken _setToken, uint256 _setQuantity, address _caller, address _to) internal {
        INAVIssuanceHook preRedeemHook = navIssuanceSettings[_setToken].managerRedemptionHook;
        if (address(preRedeemHook) != address(0)) {
            preRedeemHook.invokePreRedeemHook(_setToken, _setQuantity, _caller, _to);
        }
    }
}