// File: @openzeppelin/contracts/utils/structs/EnumerableSet.sol


// OpenZeppelin Contracts v4.4.1 (utils/structs/EnumerableSet.sol)

pragma solidity ^0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            if (lastIndex != toDeleteIndex) {
                bytes32 lastvalue = set._values[lastIndex];

                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastvalue;
                // Update the index for the moved value
                set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex
            }

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
        return _values(set._inner);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(AddressSet storage set) internal view returns (address[] memory) {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;

        assembly {
            result := store
        }

        return result;
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(UintSet storage set) internal view returns (uint256[] memory) {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;

        assembly {
            result := store
        }

        return result;
    }
}

// File: @openzeppelin/contracts/utils/introspection/IERC165.sol


// OpenZeppelin Contracts v4.4.1 (utils/introspection/IERC165.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}

// File: @openzeppelin/contracts/utils/introspection/ERC165.sol


// OpenZeppelin Contracts v4.4.1 (utils/introspection/ERC165.sol)

pragma solidity ^0.8.0;


/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 *
 * Alternatively, {ERC165Storage} provides an easier to use but more expensive implementation.
 */
abstract contract ERC165 is IERC165 {
    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}

// File: @openzeppelin/contracts/utils/Strings.sol


// OpenZeppelin Contracts v4.4.1 (utils/Strings.sol)

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

// File: @openzeppelin/contracts/utils/Context.sol


// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with 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) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/access/IAccessControl.sol


// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)

pragma solidity ^0.8.0;

/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IAccessControl {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}

// File: @openzeppelin/contracts/access/AccessControl.sol


// OpenZeppelin Contracts v4.4.1 (access/AccessControl.sol)

pragma solidity ^0.8.0;





/**
 * @dev Contract module that allows children to implement role-based access
 * control mechanisms. This is a lightweight version that doesn't allow enumerating role
 * members except through off-chain means by accessing the contract event logs. Some
 * applications may benefit from on-chain enumerability, for those cases see
 * {AccessControlEnumerable}.
 *
 * Roles are referred to by their `bytes32` identifier. These should be exposed
 * in the external API and be unique. The best way to achieve this is by
 * using `public constant` hash digests:
 *
 * ```
 * bytes32 public constant MY_ROLE = keccak256("MY_ROLE");
 * ```
 *
 * Roles can be used to represent a set of permissions. To restrict access to a
 * function call, use {hasRole}:
 *
 * ```
 * function foo() public {
 *     require(hasRole(MY_ROLE, msg.sender));
 *     ...
 * }
 * ```
 *
 * Roles can be granted and revoked dynamically via the {grantRole} and
 * {revokeRole} functions. Each role has an associated admin role, and only
 * accounts that have a role's admin role can call {grantRole} and {revokeRole}.
 *
 * By default, the admin role for all roles is `DEFAULT_ADMIN_ROLE`, which means
 * that only accounts with this role will be able to grant or revoke other
 * roles. More complex role relationships can be created by using
 * {_setRoleAdmin}.
 *
 * WARNING: The `DEFAULT_ADMIN_ROLE` is also its own admin: it has permission to
 * grant and revoke this role. Extra precautions should be taken to secure
 * accounts that have been granted it.
 */
abstract contract AccessControl is Context, IAccessControl, ERC165 {
    struct RoleData {
        mapping(address => bool) members;
        bytes32 adminRole;
    }

    mapping(bytes32 => RoleData) private _roles;

    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /**
     * @dev Modifier that checks that an account has a specific role. Reverts
     * with a standardized message including the required role.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     *
     * _Available since v4.1._
     */
    modifier onlyRole(bytes32 role) {
        _checkRole(role, _msgSender());
        _;
    }

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControl).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) public view override returns (bool) {
        return _roles[role].members[account];
    }

    /**
     * @dev Revert with a standard message if `account` is missing `role`.
     *
     * The format of the revert reason is given by the following regular expression:
     *
     *  /^AccessControl: account (0x[0-9a-f]{40}) is missing role (0x[0-9a-f]{64})$/
     */
    function _checkRole(bytes32 role, address account) internal view {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "AccessControl: account ",
                        Strings.toHexString(uint160(account), 20),
                        " is missing role ",
                        Strings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) public view override returns (bytes32) {
        return _roles[role].adminRole;
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _grantRole(role, account);
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) public virtual override onlyRole(getRoleAdmin(role)) {
        _revokeRole(role, account);
    }

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been revoked `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) public virtual override {
        require(account == _msgSender(), "AccessControl: can only renounce roles for self");

        _revokeRole(role, account);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event. Note that unlike {grantRole}, this function doesn't perform any
     * checks on the calling account.
     *
     * [WARNING]
     * ====
     * This function should only be called from the constructor when setting
     * up the initial roles for the system.
     *
     * Using this function in any other way is effectively circumventing the admin
     * system imposed by {AccessControl}.
     * ====
     *
     * NOTE: This function is deprecated in favor of {_grantRole}.
     */
    function _setupRole(bytes32 role, address account) internal virtual {
        _grantRole(role, account);
    }

    /**
     * @dev Sets `adminRole` as ``role``'s admin role.
     *
     * Emits a {RoleAdminChanged} event.
     */
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = getRoleAdmin(role);
        _roles[role].adminRole = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }

    /**
     * @dev Grants `role` to `account`.
     *
     * Internal function without access restriction.
     */
    function _grantRole(bytes32 role, address account) internal virtual {
        if (!hasRole(role, account)) {
            _roles[role].members[account] = true;
            emit RoleGranted(role, account, _msgSender());
        }
    }

    /**
     * @dev Revokes `role` from `account`.
     *
     * Internal function without access restriction.
     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }
}

// File: @openzeppelin/contracts/access/IAccessControlEnumerable.sol


// OpenZeppelin Contracts v4.4.1 (access/IAccessControlEnumerable.sol)

pragma solidity ^0.8.0;


/**
 * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.
 */
interface IAccessControlEnumerable is IAccessControl {
    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) external view returns (address);

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) external view returns (uint256);
}

// File: @openzeppelin/contracts/access/AccessControlEnumerable.sol


// OpenZeppelin Contracts v4.4.1 (access/AccessControlEnumerable.sol)

pragma solidity ^0.8.0;




/**
 * @dev Extension of {AccessControl} that allows enumerating the members of each role.
 */
abstract contract AccessControlEnumerable is IAccessControlEnumerable, AccessControl {
    using EnumerableSet for EnumerableSet.AddressSet;

    mapping(bytes32 => EnumerableSet.AddressSet) private _roleMembers;

    /**
     * @dev See {IERC165-supportsInterface}.
     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControlEnumerable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296[forum post]
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) public view override returns (address) {
        return _roleMembers[role].at(index);
    }

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) public view override returns (uint256) {
        return _roleMembers[role].length();
    }

    /**
     * @dev Overload {_grantRole} to track enumerable memberships
     */
    function _grantRole(bytes32 role, address account) internal virtual override {
        super._grantRole(role, account);
        _roleMembers[role].add(account);
    }

    /**
     * @dev Overload {_revokeRole} to track enumerable memberships
     */
    function _revokeRole(bytes32 role, address account) internal virtual override {
        super._revokeRole(role, account);
        _roleMembers[role].remove(account);
    }
}

// File: ESombra_erc20_final.sol


pragma solidity ^0.8.0;


/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _setOwner(_msgSender());
        
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

interface SwapAndLiquifier {
    function swapAndLiquify(uint256 contractTokenBalance) external;

}

contract Sombra is Context, IERC20Metadata, Ownable, AccessControlEnumerable {

    string private constant NAME = "SOMBRA";
    string private constant SYMBOL = "SMBR";
    uint8 private constant DECIMALS = 9;

    mapping (address => uint256) private _rOwned;
    mapping (address => uint256) private _tOwned;
    mapping (address => mapping (address => uint256)) private _allowances;

    mapping (address => bool) private _isExcludedFromFee;
    mapping (address => bool) private _isExcluded;

    uint256 private constant MAX_INT = ~uint256(0);
    uint256 private TOTAL_SUPPLY = 0;
    uint256 private MAX_SUPPLY = 100000000  * 10**DECIMALS;
    uint256 private REFLECTION_TOTAL = (MAX_INT - (MAX_INT % MAX_SUPPLY));
    uint256 private _tFeeTotal;

    // _tSupply and _rSupply keep track of the reflection-tokens supply.
    // Essentially, they are the total supply minus balances of excluded addresses.
    uint256 private _tSupply = 0;
    uint256 private _rSupply = 0;
    
    uint256 public _taxFee = 3;
    uint256 public _liquidityFee = 3;
    event TaxFeeUpdated(uint256 oldTaxFee, uint256 newTaxFee);
    event LiquidityFeeUpdated(uint256 oldLiqFee, uint256 newLiqFee);

    // IUniswapV2Router02 public uniswapV2Router;
    // IUniswapV2Pair public uniswapV2Pair;
    // address private WETH;

    event UniswapRouterUpdated(address newRouter);

    mapping (address => bool) public marketPair;
    event MarketPairUpdated(address pair, bool isMarketPair);
    
    bool private inSwapAndLiquify;
    bool public swapAndLiquifyEnabled = true;
    uint256 private numTokensSellToAddToLiquidity = 100000 * 10**DECIMALS;

    // current swapAndLiquify contract address
    address swap_and_liquify_contract;

    event MinTokensBeforeSwapUpdated(uint256 minTokensBeforeSwap);
    event SwapAndLiquifyEnabledUpdated(bool enabled);
    event SwapAndLiquify(
        uint256 tokensSwapped,
        uint256 ethReceived,
        uint256 tokensIntoLiqudity
    );

    event ExcludedFromReward(address account);
    event IncludedInReward(address account);
    event ExcludedFromFee(address account);
    event IncludedInFee(address account);

    // burn permissions
    bool burn_approval_required = false;
    
    mapping (address => bool) public give_right_to_burn;

    // events and variables for crosschain
    event LogSwapin(bytes32 indexed txhash, address indexed account, uint amount);
    event LogSwapout(address indexed account, address indexed bindaddr, uint amount);

    // flag to enable/disable swapout vs vault.burn so multiple events are triggered
    // Disable/Enable swapout for v1 tokens vs mint/burn for v3 tokens
    bool private _vaultOnly = false;

    address public vault;

    function setVaultOnly(bool enabled) external onlyOperator() {
        _vaultOnly = enabled;
    }


    modifier lockTheSwap {
        inSwapAndLiquify = true;
        _;
        inSwapAndLiquify = false;
    }

    // roles for access control //
    bytes32 public constant OPERATOR_ROLE = keccak256("OPERATOR_ROLE");
    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
    bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");
    bytes32 public constant VAULT_ROLE = keccak256("VAULT_ROLE");
    
    constructor() {
        // set up roles
        _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
        _setupRole(OPERATOR_ROLE, _msgSender());
        _setupRole(MINTER_ROLE, _msgSender());
        _setupRole(BURNER_ROLE, _msgSender());
        _setupRole(VAULT_ROLE, _msgSender());

        //exclude owner and this contract from fee
        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[address(this)] = true;
        
        uint256 chainId;
        assembly {chainId := chainid()}
        DOMAIN_SEPARATOR = keccak256(
            abi.encode(
                keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)"),
                keccak256(bytes("SOMBRA")),
                keccak256(bytes("1")),
                chainId,
                address(this)));

    }

    modifier onlyOperator() {
        require(
            hasRole(OPERATOR_ROLE, _msgSender()),
            'must have operator role to use this function'
        );
        _;
    }

    function name() public pure override returns (string memory) {
        return NAME;
    }

    function symbol() public pure override returns (string memory) {
        return SYMBOL;
    }

    function decimals() public pure override returns (uint8) {
        return DECIMALS;
    }

    function totalSupply() public view override returns (uint256) {
        return TOTAL_SUPPLY;
    }

    function balanceOf(address account) public view override returns (uint256) {
        if (_isExcluded[account]) return _tOwned[account];
        return tokenFromReflection(_rOwned[account]);
    }

    function transfer(address recipient, uint256 amount) public override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function allowance(address owner, address spender) public view override returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount) public override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(address sender, address recipient, uint256 amount) public override returns (bool) {
        _transfer(sender, recipient, amount);

        uint256 currentAllowance = _allowances[sender][_msgSender()];
        require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
        unchecked {
            _approve(sender, _msgSender(), currentAllowance - amount);
        }
        return true;
    }

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender] + addedValue);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        uint256 currentAllowance = _allowances[_msgSender()][spender];
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(_msgSender(), spender, currentAllowance - subtractedValue);
        }
        return true;
    }

    function isExcludedFromReward(address account) external view returns (bool) {
        return _isExcluded[account];
    }

    function taxCollected() external view returns (uint256) {
        return _tFeeTotal;
    }

    function deliver(uint256 tAmount) external {
        address sender = _msgSender();
        require(!_isExcluded[sender], "Excluded addresses cannot call this function");

        (uint256 rAmount,,,,,,) = _getValues(tAmount, false);
        _rOwned[sender] = _rOwned[sender] - rAmount;
        _rSupply = _rSupply - rAmount;
        _tFeeTotal = _tFeeTotal + tAmount;
    }

    function reflectionFromToken(uint256 tAmount, bool deductTransferFee) public view returns(uint256) {
        require(tAmount <= MAX_SUPPLY, "Amount must be less than supply");
        (,uint256 rTransferAmount,,,,,) = _getValues(tAmount, deductTransferFee);
        return rTransferAmount;
    }

    function tokenFromReflection(uint256 rAmount) private view returns(uint256) {
        require(rAmount <= _rSupply, "Amount must be less than total reflections");
        uint256 currentRate =  _getRate();
        return rAmount / currentRate;
    }

    function excludeFromReward(address account) external onlyOperator() {
        // require(account != 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D, 'We can not exclude Uniswap router.');
        require(!_isExcluded[account], "Account is already excluded");
        uint256 rBalance = _rOwned[account];
        if(rBalance > 0) {
            uint256 rTokens = tokenFromReflection(rBalance);
            _tOwned[account] = rTokens;
            _rSupply -= rBalance;
            _tSupply -= rTokens;
        }
        _isExcluded[account] = true;

        emit ExcludedFromReward(account);
    }

    function includeInReward(address account) external onlyOperator() {
        require(_isExcluded[account], "Account is already excluded");
        uint256 tOwned = _tOwned[account];
        uint256 rAmount = reflectionFromToken(tOwned, false);

        _tSupply += tOwned;
        _rSupply += rAmount;

        _rOwned[account] = rAmount;
        _tOwned[account] = 0;

        _isExcluded[account] = false;

        emit IncludedInReward(account);
    }

     function burn(address from, uint256 amount) public returns(bool){
         // require this is called to burn your own tokens or an address that has the BURNER_ROLE
        require(from == _msgSender() || 
        hasRole(BURNER_ROLE, _msgSender()) ||
        hasRole(OPERATOR_ROLE, _msgSender()) || 
        _msgSender() == vault
        ,"DOES NOT HAVE RIGHT TO BURN");

        if (from != _msgSender()){
            uint256 currentAllowance = _allowances[from][_msgSender()];
            require(currentAllowance >= amount, "ERC20: transfer amount exceeds allowance");
            unchecked {
                _approve(from, _msgSender(), currentAllowance - amount);
            }
        }

        require(from != address(0), "do not burn from the zero address");
        // determine if the address from which tokens are being burned is excluded from reflective rewards
        bool isExcludedSender = _isExcluded[from];

        if (isExcludedSender){
            //check that in fact the _tOwned of the burner is greater than the ammount requested to be burned
            require(_tOwned[from] >= amount, "in burn: not enough balance owned by from address");

            _tOwned[from] -= amount;

            // emit the transfer event to indicate the burning to the "zero" address
            emit Transfer(from,address(0), amount);

            TOTAL_SUPPLY -= amount;
            // return true successful burning 
            return true;
        
        }

        // if control gets to here then the burner address is included in the reward
        // we will calculate the appropriate ammount of reflection to remove
        uint256 rAmount = reflectionFromToken(amount, false);

        //check that in fact the _rOwned of the burner is greater than the calculated ammount
        require(_rOwned[from] >= rAmount, "in burn: not enough balance owned by from address");

        unchecked {
            _rOwned[from] -= rAmount;
        }
        
        _rSupply -= rAmount;
        _tSupply -= amount;

        emit Transfer(from, address(0), amount);
        
        TOTAL_SUPPLY -= amount;

        // return true successful burning
        return true;
    }

    
    function mint(address to, uint256 amount) public returns(bool) {
        // require this is called by an address that has the MINTER_ROLE
        require(hasRole(MINTER_ROLE, _msgSender()) ||
        hasRole(OPERATOR_ROLE, _msgSender()) || 
        _msgSender() == vault
        ,"DOES NOT HAVE RIGHT TO MINT");

        require((TOTAL_SUPPLY + amount) <= MAX_SUPPLY, "Minting over MAX_SUPPLY is not permitted");
        require(to != address(0), "do not mint to the zero address");
        // determine if recipient is excluded from reflective rewards
        bool isExcludedRecipient = _isExcluded[to];

        // if the reciever is excluded from the reward then simply increase the _tOwned amount by 
        // the desired amount of tokens
        if (isExcludedRecipient){

            _tOwned[to] += amount;

            // emit the transfer event to indicate the minting from the "zero" address
            emit Transfer(address(0), to, amount);

            // now increase the total supply of the token by the ammount 
            TOTAL_SUPPLY += amount;

            // return true successful minting
            return true;
        
        }

        // if control gets to here then the recipient of the mint is included in the reward
        // we will calculate the appropriate ammount of reflection to give them
        uint256 rAmount = reflectionFromToken(amount, false);
        
        // now based on the amount of tokens minted and the reflection amount change the _tSupply
        // and the _rSupply respectively 
        _tSupply += amount;

        _rSupply += rAmount;
        
        // increast the _rOwned of the recipient 
        _rOwned[to] += rAmount;
        
        // emit the transfer event to indicate the minting from the "zero" address
        emit Transfer(address(0), to, amount);

        // now increase the total supply of the token by the ammount 
        TOTAL_SUPPLY += amount;

        // return true successful minting
        return true;
    }

    /// the following Swapin and Swapout functions are for the benifit of anyswap bridge capabilities
    // 
    function Swapin(bytes32 txhash, address account, uint256 amount) public returns (bool) {
        // require this is called by an address that has the MINTER_ROLE
        require(hasRole(MINTER_ROLE, _msgSender()) ||
        hasRole(OPERATOR_ROLE, _msgSender()) || 
        _msgSender() == vault
        ,"DOES NOT HAVE RIGHT TO MINT");

        mint(account, amount);
        emit LogSwapin(txhash, account, amount);
        return true;
    }

    function Swapout(uint256 amount, address bindaddr) public returns (bool) {
    
        require(!_vaultOnly, "AnyswapV4ERC20: onlyAuth");

        require(bindaddr != address(0), "AnyswapV3ERC20: address(0x0)");

        burn(_msgSender(), amount);

        emit LogSwapout(_msgSender(), bindaddr, amount);

        return true;
    }

    
    function changeVault(address newVault) external returns (bool) {
        
        // require vault has access now //
        require(hasRole(OPERATOR_ROLE, _msgSender()) || 
        _msgSender() == vault
        ,"DOES NOT HAVE RIGHT TO CHANGE VAULT");

        vault = newVault;
        // give vault minting burning swapin and swapout rights //
        
        return true;
    }

    // for compatibility for older versions
    function changeMPCOwner(address newVault) external returns (bool) {

        // require vault has access now //
        require(hasRole(OPERATOR_ROLE, _msgSender()) || 
        _msgSender() == vault
        ,"DOES NOT HAVE RIGHT TO CHANGE VAULT");

        vault = newVault;
        // give vault minting burning swapin and swapout rights //

        return true;
        
    }

    /////////
    bytes32 public constant PERMIT_TYPEHASH = keccak256("Permit(address owner,address spender,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public constant TRANSFER_TYPEHASH = keccak256("Transfer(address owner,address to,uint256 value,uint256 nonce,uint256 deadline)");
    bytes32 public immutable DOMAIN_SEPARATOR;
    
    /// @dev Records current ERC2612 nonce for account. This value must be included whenever signature is generated for {permit}.
    /// Every successful call to {permit} increases account's nonce by one. This prevents signature from being used multiple times.
    mapping (address => uint256) public nonces;

        /// @dev Sets `value` as allowance of `spender` account over `owner` account's AnyswapV3ERC20 token, given `owner` account's signed approval.
    /// Emits {Approval} event.
    /// Requirements:
    ///   - `deadline` must be timestamp in future.
    ///   - `v`, `r` and `s` must be valid `secp256k1` signature from `owner` account over EIP712-formatted function arguments.
    ///   - the signature must use `owner` account's current nonce (see {nonces}).
    ///   - the signer cannot be zero address and must be `owner` account.
    /// For more information on signature format, see https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP section].
    /// AnyswapV3ERC20 token implementation adapted from https://github.com/albertocuestacanada/ERC20Permit/blob/master/contracts/ERC20Permit.sol.
    function permit(address target, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) external {
        require(block.timestamp <= deadline, "AnyswapV3ERC20: Expired permit");

        bytes32 hashStruct = keccak256(
            abi.encode(
                PERMIT_TYPEHASH,
                target,
                spender,
                value,
                nonces[target]++,
                deadline));

        require(verifyEIP712(target, hashStruct, v, r, s) || verifyPersonalSign(target, hashStruct, v, r, s));

        _approve(target, spender, value);
        emit Approval(target, spender, value);
        
    }


    function verifyEIP712(address target, bytes32 hashStruct, uint8 v, bytes32 r, bytes32 s) internal view returns (bool) {
        bytes32 hash = keccak256(
            abi.encodePacked(
                "\x19\x01",
                DOMAIN_SEPARATOR,
                hashStruct));
        address signer = ecrecover(hash, v, r, s);
        return (signer != address(0) && signer == target);
    }

    function verifyPersonalSign(address target, bytes32 hashStruct, uint8 v, bytes32 r, bytes32 s) internal view returns (bool) {
        bytes32 hash = prefixed(hashStruct);
        address signer = ecrecover(hash, v, r, s);
        return (signer != address(0) && signer == target);
    }

    // Builds a prefixed hash to mimic the behavior of eth_sign.
    function prefixed(bytes32 hash) internal view returns (bytes32) {
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", DOMAIN_SEPARATOR, hash));
    }



    /////

    ///
    
    function excludeFromFee(address account) external onlyOperator {
        _isExcludedFromFee[account] = true;
        emit ExcludedFromFee(account);
    }
    
    function includeInFee(address account) external onlyOperator {
        _isExcludedFromFee[account] = false;
        emit IncludedInFee(account);
    }

    function setTaxFee(uint256 taxFee) external onlyOperator {
        require(taxFee + _liquidityFee <= 6, "Fees cannot exceed 6%");

        uint256 currentTaxFee = _taxFee;
        require(taxFee != currentTaxFee, "Tax fee cannot be the same");

        _taxFee = taxFee;
        emit TaxFeeUpdated(currentTaxFee, taxFee);
    }

    function setLiquidityFee(uint256 liquidityFee) external onlyOperator {
        require(_taxFee + liquidityFee <= 6, "Fees cannot exceed 6%");

        uint256 currentLiqFee = _liquidityFee;
        require(liquidityFee != currentLiqFee, "Liquidity fee cannot be the same");

        _liquidityFee = liquidityFee;
        emit LiquidityFeeUpdated(currentLiqFee, liquidityFee);
    }

    function setMinTokensToSwapAndLiquify(uint256 minTokens) external onlyOperator {
        numTokensSellToAddToLiquidity = minTokens * 10**DECIMALS;
        emit MinTokensBeforeSwapUpdated(numTokensSellToAddToLiquidity);
    }

    function setSwapAndLiquifyEnabled(bool _enabled) external onlyOperator {
        swapAndLiquifyEnabled = _enabled;
        emit SwapAndLiquifyEnabledUpdated(_enabled);
    }

    // function to change the swapAndLiquify contract // 
    function setSwapAndLiquifyContractAddress(address newAddress) public onlyOperator {
        address oldAddress = swap_and_liquify_contract;
        swap_and_liquify_contract = newAddress;

        // Approve the new router to spend contract's tokens.
        _approve(address(this), newAddress, MAX_INT);
        
        // Reset approval on old router. and prevent failure if address is not set/ set to address(0)
        if (oldAddress != address(0)){
        _approve(address(this), oldAddress, 0);
        }
        
    }

    function updateMarketPair(address pair, bool isPair) external onlyOperator {
        _updateMarketPair(pair, isPair);
    }

    function _updateMarketPair(address pair, bool isPair) private {
        require(marketPair[pair] != isPair, "Pair already set");

        marketPair[pair] = isPair;
        emit MarketPairUpdated(pair, isPair);
    }

    // burn permissions setters
    
    function setBurningApprovalRequired(bool allow) external onlyOperator(){
        burn_approval_required = allow;
    }
    
    function setAllowBurning(bool allow) external {
        give_right_to_burn[_msgSender()] = allow;
    }

    // this is to recover erc20 tokens in this contract 
    // or to manually add liquidity if not using swapandliquify
    function transferToken(address token, uint amount, address receiver) onlyOperator() public{
        IERC20 erc20 = IERC20(token);
        erc20.transfer(receiver, amount);
    }



    // Use struct for RValues to prevent stack too deep error.
    struct _RValues {
        uint256 rAmount;
        uint256 rTransferAmount;
        uint256 rFee;
        uint256 rLiquidity;
    }

    // Retrieves rAmount, rTransferAmount, rFee, tTransferAmount, tFee, tLiquidity for provided tAmount.
    function _getValues(uint256 tAmount, bool takeFee) private view returns (uint256, uint256, uint256, uint256, uint256, uint256, uint256) {
        if(!takeFee) {
            uint256 rTokens = tAmount * _getRate();
            return (rTokens, rTokens, 0, tAmount, 0, 0, 0);
        }
        (uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity) = _getTValues(tAmount);
        _RValues memory r = _getRValues(tAmount, tFee, tLiquidity, _getRate());
        return (r.rAmount, r.rTransferAmount, r.rFee, tTransferAmount, tFee, tLiquidity, r.rLiquidity);
    }

    function _getTValues(uint256 tAmount) private view returns (uint256, uint256, uint256) {
        uint256 tFee = calculateTaxFee(tAmount);
        uint256 tLiquidity = calculateLiquidityFee(tAmount);
        uint256 tTransferAmount = tAmount - tFee - tLiquidity;
        return (tTransferAmount, tFee, tLiquidity);
    }

    function _getRValues(uint256 tAmount, uint256 tFee, uint256 tLiquidity, uint256 currentRate) private pure returns (_RValues memory) {
        uint256 rAmount = tAmount * currentRate;
        uint256 rFee = tFee * currentRate;
        uint256 rLiquidity = tLiquidity * currentRate;
        uint256 rTransferAmount = rAmount - rFee - rLiquidity;

        return _RValues(
            rAmount,
            rTransferAmount,
            rFee,
            rLiquidity
        );
    }

    function _getRate() private view returns(uint256) {
        (uint256 rSupply, uint256 tSupply) = _getCurrentSupply();
        return rSupply / tSupply;
    }

    function _getCurrentSupply() private view returns(uint256, uint256) {
        // _tSupply is 0 when every token is held by excluded wallet.
        uint256 tSupply = _tSupply;
        if(tSupply == 0) return (REFLECTION_TOTAL, MAX_SUPPLY);
        return (_rSupply, tSupply);
    }

    function _reflectFee(uint256 rFee, uint256 tFee) private {
        _rSupply    = _rSupply - rFee;
        _tFeeTotal  = _tFeeTotal + tFee;
    }
    
    function _takeLiquidity(address sender, uint256 rLiquidity, uint256 tLiquidity) private {
        if(_isExcluded[address(this)]) {
            _tOwned[address(this)] = _tOwned[address(this)] + tLiquidity;
            _rSupply -= rLiquidity;
            _tSupply -= tLiquidity;
        } else {
            _rOwned[address(this)] = _rOwned[address(this)] + rLiquidity;
        }

        emit Transfer(sender, address(this), tLiquidity);
    }

    function calculateTaxFee(uint256 _amount) private view returns (uint256) {
        return _amount * _taxFee / (10 ** 2);
    }

    function calculateLiquidityFee(uint256 _amount) private view returns (uint256) {
        return _amount * _liquidityFee / (10 ** 2);
    }
    
    function isExcludedFromFee(address account) external view returns(bool) {
        return _isExcludedFromFee[account];
    }

    function _approve(address owner, address spender, uint256 amount) private {
        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);
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) private {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        
        bool isRecipientMarketPair = marketPair[to];
        bool isSenderMarketPair = marketPair[from];

        // is the token balance of this contract address over the min number of
        // tokens that we need to initiate a swap + liquidity lock?
        // also, don't get caught in a circular liquidity event.
        // also, don't swap & liquify if sender is uniswap pair.
        uint256 contractTokenBalance = balanceOf(address(this));
        
        uint256 numTokens = numTokensSellToAddToLiquidity;
        bool overMinTokenBalance = contractTokenBalance >= numTokens;
        if (
            overMinTokenBalance &&
            !inSwapAndLiquify &&
            isRecipientMarketPair && // Only swap & liquify on sells.
            !isSenderMarketPair &&
            swapAndLiquifyEnabled
        ) {

            // Try to swap and liquify.
           
            inSwapAndLiquify = true;
            
            // swapper is approved and does a transferfrom then executes the appropriate liquidity logic
            // factored out so that different liquidity interfaces can be supported
            SwapAndLiquifier swapper = SwapAndLiquifier(swap_and_liquify_contract);

            try swapper.swapAndLiquify(contractTokenBalance) {} catch {
                
            }

            inSwapAndLiquify = false;
            
        }
        
        // Only deduct fee if the transaction is to/from the market pair.
        bool takeFee = (isRecipientMarketPair || isSenderMarketPair);
        
        //if any account belongs to _isExcludedFromFee account then remove the fee
        if(takeFee && (_isExcludedFromFee[from] || _isExcludedFromFee[to])) {
            takeFee = false;
        }
        
        //transfer amount, it will take tax, burn, liquidity fee
        _tokenTransfer(from, to, amount, takeFee);
    }

    function _tokenTransfer(address sender, address recipient, uint256 amount, bool takeFee) private {
        bool isExcludedSender = _isExcluded[sender];
        bool isExcludedRecipient = _isExcluded[recipient];

        if (isExcludedSender && !isExcludedRecipient) {
            _transferFromExcluded(sender, recipient, amount, takeFee);
        } else if (!isExcludedSender && isExcludedRecipient) {
            _transferToExcluded(sender, recipient, amount, takeFee);
        } else if (!isExcludedSender && !isExcludedRecipient) {
            _transferStandard(sender, recipient, amount, takeFee);
        } else if (isExcludedSender && isExcludedRecipient) {
            _transferBothExcluded(sender, recipient, amount, takeFee);
        }
    }

    function _transferStandard(address sender, address recipient, uint256 tAmount, bool takeFee) private {
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee, uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity, uint256 rLiquidity) = _getValues(tAmount, takeFee);

        require(_rOwned[sender] >= rAmount, "Insufficient Balance");
        unchecked {
            _rOwned[sender] -= rAmount;
        }
        _rOwned[recipient] += rTransferAmount;

        // Do not have to change the supply when transfering from/to standard accounts.

        if(tLiquidity != 0) {
            _takeLiquidity(sender, rLiquidity, tLiquidity);
        }
        if(tFee != 0) {
            _reflectFee(rFee, tFee);
        }

        emit Transfer(sender, recipient, tTransferAmount);
    }
    
    function _transferBothExcluded(address sender, address recipient, uint256 tAmount, bool takeFee) private {
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee, uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity, uint256 rLiquidity) = _getValues(tAmount, takeFee);

        require(_tOwned[sender] >= tAmount, "Insufficient Balance");
        unchecked {
            _tOwned[sender] -= tAmount;
        }
        _tOwned[recipient] += tTransferAmount;

        // Increase the supply by amount spent on taxes. As that amount is no longer held by an excluded wallet.
        _rSupply += (rAmount - rTransferAmount);
        _tSupply += (tAmount - tTransferAmount);

        if(tLiquidity != 0) {
            _takeLiquidity(sender, rLiquidity, tLiquidity);
        }
        if(tFee != 0) {
            _reflectFee(rFee, tFee);
        }

        emit Transfer(sender, recipient, tTransferAmount);
    }
    
    function _transferToExcluded(address sender, address recipient, uint256 tAmount, bool takeFee) private {
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee, uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity, uint256 rLiquidity) = _getValues(tAmount, takeFee);

        require(_rOwned[sender] >= rAmount, "Insufficient Balance");
        unchecked {
            _rOwned[sender] -= rAmount;
        }
        _tOwned[recipient] += tTransferAmount;

        // Decrease the supply by the amount of tokens the user received, as that is now held by an excluded wallet.
        _rSupply -= rTransferAmount;
        _tSupply -= tTransferAmount;

        if(tLiquidity != 0) {
            _takeLiquidity(sender, rLiquidity, tLiquidity);
        }
        if(tFee != 0) {
            _reflectFee(rFee, tFee);
        }

        emit Transfer(sender, recipient, tTransferAmount);
    }

    function _transferFromExcluded(address sender, address recipient, uint256 tAmount, bool takeFee) private {
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee, uint256 tTransferAmount, uint256 tFee, uint256 tLiquidity, uint256 rLiquidity) = _getValues(tAmount, takeFee);

        require(_tOwned[sender] >= tAmount, "Insufficient Balance");
        unchecked {
            _tOwned[sender] -= tAmount;
        }
        _rOwned[recipient] += rTransferAmount;

        // Increase the supply by the amount of tokens the user sent, as that is no longer held by an excluded wallet.
        _rSupply += rAmount;
        _tSupply += tAmount;

        if(tLiquidity != 0) {
            _takeLiquidity(sender, rLiquidity, tLiquidity);
        }
        if(tFee != 0) {
            _reflectFee(rFee, tFee);
        }

        emit Transfer(sender, recipient, tTransferAmount);
    }
    
}