organized_contracts/2b/2b044da4b785cf667ce6532a0acffe0b88a7cec672dea134e1f056064eb94722/main.sol

// This contract is part of Zellic’s smart contract dataset, which is a collection of publicly available contract code gathered as of March 2023.

// Sources flattened with hardhat v2.3.0 https://hardhat.org

// File @openzeppelin/contracts-upgradeable/token/ERC777/[email protected]

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC777/IERC777.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface of the ERC777Token standard as defined in the EIP.

 *

 * This contract uses the

 * https://eips.ethereum.org/EIPS/eip-1820[ERC1820 registry standard] to let

 * token holders and recipients react to token movements by using setting implementers

 * for the associated interfaces in said registry. See {IERC1820Registry} and

 * {ERC1820Implementer}.

 */
interface IERC777Upgradeable {
    /**

     * @dev Emitted when `amount` tokens are created by `operator` and assigned to `to`.

     *

     * Note that some additional user `data` and `operatorData` can be logged in the event.

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

    /**

     * @dev Emitted when `operator` destroys `amount` tokens from `account`.

     *

     * Note that some additional user `data` and `operatorData` can be logged in the event.

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

    /**

     * @dev Emitted when `operator` is made operator for `tokenHolder`.

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

    /**

     * @dev Emitted when `operator` is revoked its operator status for `tokenHolder`.

     */
    event RevokedOperator(address indexed operator, address indexed tokenHolder);

    /**

     * @dev Returns the name of the token.

     */
    function name() external view returns (string memory);

    /**

     * @dev Returns the symbol of the token, usually a shorter version of the

     * name.

     */
    function symbol() external view returns (string memory);

    /**

     * @dev Returns the smallest part of the token that is not divisible. This

     * means all token operations (creation, movement and destruction) must have

     * amounts that are a multiple of this number.

     *

     * For most token contracts, this value will equal 1.

     */
    function granularity() external view returns (uint256);

    /**

     * @dev Returns the amount of tokens in existence.

     */
    function totalSupply() external view returns (uint256);

    /**

     * @dev Returns the amount of tokens owned by an account (`owner`).

     */
    function balanceOf(address owner) external view returns (uint256);

    /**

     * @dev Moves `amount` tokens from the caller's account to `recipient`.

     *

     * If send or receive hooks are registered for the caller and `recipient`,

     * the corresponding functions will be called with `data` and empty

     * `operatorData`. See {IERC777Sender} and {IERC777Recipient}.

     *

     * Emits a {Sent} event.

     *

     * Requirements

     *

     * - the caller must have at least `amount` tokens.

     * - `recipient` cannot be the zero address.

     * - if `recipient` is a contract, it must implement the {IERC777Recipient}

     * interface.

     */
    function send(
        address recipient,
        uint256 amount,
        bytes calldata data
    ) external;

    /**

     * @dev Destroys `amount` tokens from the caller's account, reducing the

     * total supply.

     *

     * If a send hook is registered for the caller, the corresponding function

     * will be called with `data` and empty `operatorData`. See {IERC777Sender}.

     *

     * Emits a {Burned} event.

     *

     * Requirements

     *

     * - the caller must have at least `amount` tokens.

     */
    function burn(uint256 amount, bytes calldata data) external;

    /**

     * @dev Returns true if an account is an operator of `tokenHolder`.

     * Operators can send and burn tokens on behalf of their owners. All

     * accounts are their own operator.

     *

     * See {operatorSend} and {operatorBurn}.

     */
    function isOperatorFor(address operator, address tokenHolder) external view returns (bool);

    /**

     * @dev Make an account an operator of the caller.

     *

     * See {isOperatorFor}.

     *

     * Emits an {AuthorizedOperator} event.

     *

     * Requirements

     *

     * - `operator` cannot be calling address.

     */
    function authorizeOperator(address operator) external;

    /**

     * @dev Revoke an account's operator status for the caller.

     *

     * See {isOperatorFor} and {defaultOperators}.

     *

     * Emits a {RevokedOperator} event.

     *

     * Requirements

     *

     * - `operator` cannot be calling address.

     */
    function revokeOperator(address operator) external;

    /**

     * @dev Returns the list of default operators. These accounts are operators

     * for all token holders, even if {authorizeOperator} was never called on

     * them.

     *

     * This list is immutable, but individual holders may revoke these via

     * {revokeOperator}, in which case {isOperatorFor} will return false.

     */
    function defaultOperators() external view returns (address[] memory);

    /**

     * @dev Moves `amount` tokens from `sender` to `recipient`. The caller must

     * be an operator of `sender`.

     *

     * If send or receive hooks are registered for `sender` and `recipient`,

     * the corresponding functions will be called with `data` and

     * `operatorData`. See {IERC777Sender} and {IERC777Recipient}.

     *

     * Emits a {Sent} event.

     *

     * Requirements

     *

     * - `sender` cannot be the zero address.

     * - `sender` must have at least `amount` tokens.

     * - the caller must be an operator for `sender`.

     * - `recipient` cannot be the zero address.

     * - if `recipient` is a contract, it must implement the {IERC777Recipient}

     * interface.

     */
    function operatorSend(

        address sender,

        address recipient,

        uint256 amount,

        bytes calldata data,

        bytes calldata operatorData

    ) external;

    /**

     * @dev Destroys `amount` tokens from `account`, reducing the total supply.

     * The caller must be an operator of `account`.

     *

     * If a send hook is registered for `account`, the corresponding function

     * will be called with `data` and `operatorData`. See {IERC777Sender}.

     *

     * Emits a {Burned} event.

     *

     * Requirements

     *

     * - `account` cannot be the zero address.

     * - `account` must have at least `amount` tokens.

     * - the caller must be an operator for `account`.

     */
    function operatorBurn(

        address account,

        uint256 amount,

        bytes calldata data,

        bytes calldata operatorData

    ) external;

    event Sent(

        address indexed operator,

        address indexed from,

        address indexed to,

        uint256 amount,

        bytes data,

        bytes operatorData

    );
}


// File @openzeppelin/contracts-upgradeable/token/ERC777/[email protected]


// OpenZeppelin Contracts v4.4.1 (token/ERC777/IERC777Recipient.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface of the ERC777TokensRecipient standard as defined in the EIP.

 *

 * Accounts can be notified of {IERC777} tokens being sent to them by having a

 * contract implement this interface (contract holders can be their own

 * implementer) and registering it on the

 * https://eips.ethereum.org/EIPS/eip-1820[ERC1820 global registry].

 *

 * See {IERC1820Registry} and {ERC1820Implementer}.

 */
interface IERC777RecipientUpgradeable {
    /**

     * @dev Called by an {IERC777} token contract whenever tokens are being

     * moved or created into a registered account (`to`). The type of operation

     * is conveyed by `from` being the zero address or not.

     *

     * This call occurs _after_ the token contract's state is updated, so

     * {IERC777-balanceOf}, etc., can be used to query the post-operation state.

     *

     * This function may revert to prevent the operation from being executed.

     */
    function tokensReceived(

        address operator,

        address from,

        address to,

        uint256 amount,

        bytes calldata userData,

        bytes calldata operatorData

    ) external;
}


// File @openzeppelin/contracts-upgradeable/token/ERC777/[email protected]


// OpenZeppelin Contracts v4.4.1 (token/ERC777/IERC777Sender.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface of the ERC777TokensSender standard as defined in the EIP.

 *

 * {IERC777} Token holders can be notified of operations performed on their

 * tokens by having a contract implement this interface (contract holders can be

 * their own implementer) and registering it on the

 * https://eips.ethereum.org/EIPS/eip-1820[ERC1820 global registry].

 *

 * See {IERC1820Registry} and {ERC1820Implementer}.

 */
interface IERC777SenderUpgradeable {
    /**

     * @dev Called by an {IERC777} token contract whenever a registered holder's

     * (`from`) tokens are about to be moved or destroyed. The type of operation

     * is conveyed by `to` being the zero address or not.

     *

     * This call occurs _before_ the token contract's state is updated, so

     * {IERC777-balanceOf}, etc., can be used to query the pre-operation state.

     *

     * This function may revert to prevent the operation from being executed.

     */
    function tokensToSend(

        address operator,

        address from,

        address to,

        uint256 amount,

        bytes calldata userData,

        bytes calldata operatorData

    ) external;
}


// File @openzeppelin/contracts-upgradeable/token/ERC20/[email protected]


// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface of the ERC20 standard as defined in the EIP.

 */
interface IERC20Upgradeable {
    /**

     * @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 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 `to`.

     *

     * Returns a boolean value indicating whether the operation succeeded.

     *

     * Emits a {Transfer} event.

     */
    function transfer(address to, 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 `from` to `to` 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 from,

        address to,

        uint256 amount

    ) external returns (bool);
}


// File @openzeppelin/contracts-upgradeable/utils/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**

 * @dev Collection of functions related to the address type

 */
library AddressUpgradeable {
    /**

     * @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

     * ====

     *

     * [IMPORTANT]

     * ====

     * You shouldn't rely on `isContract` to protect against flash loan attacks!

     *

     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets

     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract

     * constructor.

     * ====

     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**

     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to

     * `recipient`, forwarding all available gas and reverting on errors.

     *

     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost

     * of certain opcodes, possibly making contracts go over the 2300 gas limit

     * imposed by `transfer`, making them unable to receive funds via

     * `transfer`. {sendValue} removes this limitation.

     *

     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].

     *

     * IMPORTANT: because control is transferred to `recipient`, care must be

     * taken to not create reentrancy vulnerabilities. Consider using

     * {ReentrancyGuard} or the

     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].

     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (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 functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],

     * but performing a static call.

     *

     * _Available since v3.3._

     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],

     * but performing a static call.

     *

     * _Available since v3.3._

     */
    function functionStaticCall(

        address target,

        bytes memory data,

        string memory errorMessage

    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**

     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling

     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.

     *

     * _Available since v4.8._

     */
    function verifyCallResultFromTarget(

        address target,

        bool success,

        bytes memory returndata,

        string memory errorMessage

    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**

     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the

     * revert reason or using the provided one.

     *

     * _Available since v4.3._

     */
    function verifyCallResult(

        bool success,

        bytes memory returndata,

        string memory errorMessage

    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // 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
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}


// File @openzeppelin/contracts-upgradeable/proxy/utils/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

/**

 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed

 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an

 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer

 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.

 *

 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be

 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in

 * case an upgrade adds a module that needs to be initialized.

 *

 * For example:

 *

 * [.hljs-theme-light.nopadding]

 * ```

 * contract MyToken is ERC20Upgradeable {

 *     function initialize() initializer public {

 *         __ERC20_init("MyToken", "MTK");

 *     }

 * }

 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {

 *     function initializeV2() reinitializer(2) public {

 *         __ERC20Permit_init("MyToken");

 *     }

 * }

 * ```

 *

 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as

 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.

 *

 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure

 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.

 *

 * [CAUTION]

 * ====

 * Avoid leaving a contract uninitialized.

 *

 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation

 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke

 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:

 *

 * [.hljs-theme-light.nopadding]

 * ```

 * /// @custom:oz-upgrades-unsafe-allow constructor

 * constructor() {

 *     _disableInitializers();

 * }

 * ```

 * ====

 */
abstract contract Initializable {
    /**

     * @dev Indicates that the contract has been initialized.

     * @custom:oz-retyped-from bool

     */
    uint8 private _initialized;

    /**

     * @dev Indicates that the contract is in the process of being initialized.

     */
    bool private _initializing;

    /**

     * @dev Triggered when the contract has been initialized or reinitialized.

     */
    event Initialized(uint8 version);

    /**

     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,

     * `onlyInitializing` functions can be used to initialize parent contracts.

     *

     * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a

     * constructor.

     *

     * Emits an {Initialized} event.

     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**

     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the

     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be

     * used to initialize parent contracts.

     *

     * A reinitializer may be used after the original initialization step. This is essential to configure modules that

     * are added through upgrades and that require initialization.

     *

     * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`

     * cannot be nested. If one is invoked in the context of another, execution will revert.

     *

     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in

     * a contract, executing them in the right order is up to the developer or operator.

     *

     * WARNING: setting the version to 255 will prevent any future reinitialization.

     *

     * Emits an {Initialized} event.

     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**

     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the

     * {initializer} and {reinitializer} modifiers, directly or indirectly.

     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**

     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.

     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized

     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called

     * through proxies.

     *

     * Emits an {Initialized} event the first time it is successfully executed.

     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }

    /**

     * @dev Internal function that returns the initialized version. Returns `_initialized`

     */
    function _getInitializedVersion() internal view returns (uint8) {
        return _initialized;
    }

    /**

     * @dev Internal function that returns the initialized version. Returns `_initializing`

     */
    function _isInitializing() internal view returns (bool) {
        return _initializing;
    }
}


// File @openzeppelin/contracts-upgradeable/utils/[email protected]


// 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 ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }

    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */
    uint256[50] private __gap;
}


// File @openzeppelin/contracts-upgradeable/utils/introspection/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (utils/introspection/IERC1820Registry.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface of the global ERC1820 Registry, as defined in the

 * https://eips.ethereum.org/EIPS/eip-1820[EIP]. Accounts may register

 * implementers for interfaces in this registry, as well as query support.

 *

 * Implementers may be shared by multiple accounts, and can also implement more

 * than a single interface for each account. Contracts can implement interfaces

 * for themselves, but externally-owned accounts (EOA) must delegate this to a

 * contract.

 *

 * {IERC165} interfaces can also be queried via the registry.

 *

 * For an in-depth explanation and source code analysis, see the EIP text.

 */
interface IERC1820RegistryUpgradeable {
    event InterfaceImplementerSet(address indexed account, bytes32 indexed interfaceHash, address indexed implementer);

    event ManagerChanged(address indexed account, address indexed newManager);

    /**

     * @dev Sets `newManager` as the manager for `account`. A manager of an

     * account is able to set interface implementers for it.

     *

     * By default, each account is its own manager. Passing a value of `0x0` in

     * `newManager` will reset the manager to this initial state.

     *

     * Emits a {ManagerChanged} event.

     *

     * Requirements:

     *

     * - the caller must be the current manager for `account`.

     */
    function setManager(address account, address newManager) external;

    /**

     * @dev Returns the manager for `account`.

     *

     * See {setManager}.

     */
    function getManager(address account) external view returns (address);

    /**

     * @dev Sets the `implementer` contract as ``account``'s implementer for

     * `interfaceHash`.

     *

     * `account` being the zero address is an alias for the caller's address.

     * The zero address can also be used in `implementer` to remove an old one.

     *

     * See {interfaceHash} to learn how these are created.

     *

     * Emits an {InterfaceImplementerSet} event.

     *

     * Requirements:

     *

     * - the caller must be the current manager for `account`.

     * - `interfaceHash` must not be an {IERC165} interface id (i.e. it must not

     * end in 28 zeroes).

     * - `implementer` must implement {IERC1820Implementer} and return true when

     * queried for support, unless `implementer` is the caller. See

     * {IERC1820Implementer-canImplementInterfaceForAddress}.

     */
    function setInterfaceImplementer(

        address account,

        bytes32 _interfaceHash,

        address implementer

    ) external;

    /**

     * @dev Returns the implementer of `interfaceHash` for `account`. If no such

     * implementer is registered, returns the zero address.

     *

     * If `interfaceHash` is an {IERC165} interface id (i.e. it ends with 28

     * zeroes), `account` will be queried for support of it.

     *

     * `account` being the zero address is an alias for the caller's address.

     */
    function getInterfaceImplementer(address account, bytes32 _interfaceHash) external view returns (address);

    /**

     * @dev Returns the interface hash for an `interfaceName`, as defined in the

     * corresponding

     * https://eips.ethereum.org/EIPS/eip-1820#interface-name[section of the EIP].

     */
    function interfaceHash(string calldata interfaceName) external pure returns (bytes32);

    /**

     * @notice Updates the cache with whether the contract implements an ERC165 interface or not.

     * @param account Address of the contract for which to update the cache.

     * @param interfaceId ERC165 interface for which to update the cache.

     */
    function updateERC165Cache(address account, bytes4 interfaceId) external;

    /**

     * @notice Checks whether a contract implements an ERC165 interface or not.

     * If the result is not cached a direct lookup on the contract address is performed.

     * If the result is not cached or the cached value is out-of-date, the cache MUST be updated manually by calling

     * {updateERC165Cache} with the contract address.

     * @param account Address of the contract to check.

     * @param interfaceId ERC165 interface to check.

     * @return True if `account` implements `interfaceId`, false otherwise.

     */
    function implementsERC165Interface(address account, bytes4 interfaceId) external view returns (bool);

    /**

     * @notice Checks whether a contract implements an ERC165 interface or not without using or updating the cache.

     * @param account Address of the contract to check.

     * @param interfaceId ERC165 interface to check.

     * @return True if `account` implements `interfaceId`, false otherwise.

     */
    function implementsERC165InterfaceNoCache(address account, bytes4 interfaceId) external view returns (bool);
}


// File @openzeppelin/contracts-upgradeable/token/ERC777/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC777/ERC777.sol)

pragma solidity ^0.8.0;








/**

 * @dev Implementation of the {IERC777} 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}.

 *

 * Support for ERC20 is included in this contract, as specified by the EIP: both

 * the ERC777 and ERC20 interfaces can be safely used when interacting with it.

 * Both {IERC777-Sent} and {IERC20-Transfer} events are emitted on token

 * movements.

 *

 * Additionally, the {IERC777-granularity} value is hard-coded to `1`, meaning that there

 * are no special restrictions in the amount of tokens that created, moved, or

 * destroyed. This makes integration with ERC20 applications seamless.

 */
contract ERC777Upgradeable is Initializable, ContextUpgradeable, IERC777Upgradeable, IERC20Upgradeable {
    using AddressUpgradeable for address;

    IERC1820RegistryUpgradeable internal constant _ERC1820_REGISTRY = IERC1820RegistryUpgradeable(0x1820a4B7618BdE71Dce8cdc73aAB6C95905faD24);

    mapping(address => uint256) private _balances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    bytes32 private constant _TOKENS_SENDER_INTERFACE_HASH = keccak256("ERC777TokensSender");
    bytes32 private constant _TOKENS_RECIPIENT_INTERFACE_HASH = keccak256("ERC777TokensRecipient");

    // This isn't ever read from - it's only used to respond to the defaultOperators query.
    address[] private _defaultOperatorsArray;

    // Immutable, but accounts may revoke them (tracked in __revokedDefaultOperators).
    mapping(address => bool) private _defaultOperators;

    // For each account, a mapping of its operators and revoked default operators.
    mapping(address => mapping(address => bool)) private _operators;
    mapping(address => mapping(address => bool)) private _revokedDefaultOperators;

    // ERC20-allowances
    mapping(address => mapping(address => uint256)) private _allowances;

    /**

     * @dev `defaultOperators` may be an empty array.

     */
    function __ERC777_init(

        string memory name_,

        string memory symbol_,

        address[] memory defaultOperators_

    ) internal onlyInitializing {
        __ERC777_init_unchained(name_, symbol_, defaultOperators_);
    }

    function __ERC777_init_unchained(

        string memory name_,

        string memory symbol_,

        address[] memory defaultOperators_

    ) internal onlyInitializing {
        _name = name_;
        _symbol = symbol_;

        _defaultOperatorsArray = defaultOperators_;
        for (uint256 i = 0; i < defaultOperators_.length; i++) {
            _defaultOperators[defaultOperators_[i]] = true;
        }

        // register interfaces
        _ERC1820_REGISTRY.setInterfaceImplementer(address(this), keccak256("ERC777Token"), address(this));
        _ERC1820_REGISTRY.setInterfaceImplementer(address(this), keccak256("ERC20Token"), address(this));
    }

    /**

     * @dev See {IERC777-name}.

     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**

     * @dev See {IERC777-symbol}.

     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**

     * @dev See {ERC20-decimals}.

     *

     * Always returns 18, as per the

     * [ERC777 EIP](https://eips.ethereum.org/EIPS/eip-777#backward-compatibility).

     */
    function decimals() public pure virtual returns (uint8) {
        return 18;
    }

    /**

     * @dev See {IERC777-granularity}.

     *

     * This implementation always returns `1`.

     */
    function granularity() public view virtual override returns (uint256) {
        return 1;
    }

    /**

     * @dev See {IERC777-totalSupply}.

     */
    function totalSupply() public view virtual override(IERC20Upgradeable, IERC777Upgradeable) returns (uint256) {
        return _totalSupply;
    }

    /**

     * @dev Returns the amount of tokens owned by an account (`tokenHolder`).

     */
    function balanceOf(address tokenHolder) public view virtual override(IERC20Upgradeable, IERC777Upgradeable) returns (uint256) {
        return _balances[tokenHolder];
    }

    /**

     * @dev See {IERC777-send}.

     *

     * Also emits a {IERC20-Transfer} event for ERC20 compatibility.

     */
    function send(
        address recipient,
        uint256 amount,
        bytes memory data
    ) public virtual override {
        _send(_msgSender(), recipient, amount, data, "", true);
    }

    /**

     * @dev See {IERC20-transfer}.

     *

     * Unlike `send`, `recipient` is _not_ required to implement the {IERC777Recipient}

     * interface if it is a contract.

     *

     * Also emits a {Sent} event.

     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _send(_msgSender(), recipient, amount, "", "", false);
        return true;
    }

    /**

     * @dev See {IERC777-burn}.

     *

     * Also emits a {IERC20-Transfer} event for ERC20 compatibility.

     */
    function burn(uint256 amount, bytes memory data) public virtual override {
        _burn(_msgSender(), amount, data, "");
    }

    /**

     * @dev See {IERC777-isOperatorFor}.

     */
    function isOperatorFor(address operator, address tokenHolder) public view virtual override returns (bool) {
        return
            operator == tokenHolder ||

            (_defaultOperators[operator] && !_revokedDefaultOperators[tokenHolder][operator]) ||

            _operators[tokenHolder][operator];
    }

    /**

     * @dev See {IERC777-authorizeOperator}.

     */
    function authorizeOperator(address operator) public virtual override {
        require(_msgSender() != operator, "ERC777: authorizing self as operator");

        if (_defaultOperators[operator]) {
            delete _revokedDefaultOperators[_msgSender()][operator];
        } else {
            _operators[_msgSender()][operator] = true;
        }

        emit AuthorizedOperator(operator, _msgSender());
    }

    /**

     * @dev See {IERC777-revokeOperator}.

     */
    function revokeOperator(address operator) public virtual override {
        require(operator != _msgSender(), "ERC777: revoking self as operator");

        if (_defaultOperators[operator]) {
            _revokedDefaultOperators[_msgSender()][operator] = true;
        } else {
            delete _operators[_msgSender()][operator];
        }

        emit RevokedOperator(operator, _msgSender());
    }

    /**

     * @dev See {IERC777-defaultOperators}.

     */
    function defaultOperators() public view virtual override returns (address[] memory) {
        return _defaultOperatorsArray;
    }

    /**

     * @dev See {IERC777-operatorSend}.

     *

     * Emits {Sent} and {IERC20-Transfer} events.

     */
    function operatorSend(

        address sender,

        address recipient,

        uint256 amount,

        bytes memory data,

        bytes memory operatorData

    ) public virtual override {
        require(isOperatorFor(_msgSender(), sender), "ERC777: caller is not an operator for holder");
        _send(sender, recipient, amount, data, operatorData, true);
    }

    /**

     * @dev See {IERC777-operatorBurn}.

     *

     * Emits {Burned} and {IERC20-Transfer} events.

     */
    function operatorBurn(

        address account,

        uint256 amount,

        bytes memory data,

        bytes memory operatorData

    ) public virtual override {
        require(isOperatorFor(_msgSender(), account), "ERC777: caller is not an operator for holder");
        _burn(account, amount, data, operatorData);
    }

    /**

     * @dev See {IERC20-allowance}.

     *

     * Note that operator and allowance concepts are orthogonal: operators may

     * not have allowance, and accounts with allowance may not be operators

     * themselves.

     */
    function allowance(address holder, address spender) public view virtual override returns (uint256) {
        return _allowances[holder][spender];
    }

    /**

     * @dev See {IERC20-approve}.

     *

     * NOTE: If `value` is the maximum `uint256`, the allowance is not updated on

     * `transferFrom`. This is semantically equivalent to an infinite approval.

     *

     * Note that accounts cannot have allowance issued by their operators.

     */
    function approve(address spender, uint256 value) public virtual override returns (bool) {
        address holder = _msgSender();
        _approve(holder, spender, value);
        return true;
    }

    /**

     * @dev See {IERC20-transferFrom}.

     *

     * NOTE: Does not update the allowance if the current allowance

     * is the maximum `uint256`.

     *

     * Note that operator and allowance concepts are orthogonal: operators cannot

     * call `transferFrom` (unless they have allowance), and accounts with

     * allowance cannot call `operatorSend` (unless they are operators).

     *

     * Emits {Sent}, {IERC20-Transfer} and {IERC20-Approval} events.

     */
    function transferFrom(

        address holder,

        address recipient,

        uint256 amount

    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(holder, spender, amount);
        _send(holder, recipient, amount, "", "", false);
        return true;
    }

    /**

     * @dev Creates `amount` tokens and assigns them to `account`, increasing

     * the total supply.

     *

     * If a send hook is registered for `account`, the corresponding function

     * will be called with the caller address as the `operator` and with

     * `userData` and `operatorData`.

     *

     * See {IERC777Sender} and {IERC777Recipient}.

     *

     * Emits {Minted} and {IERC20-Transfer} events.

     *

     * Requirements

     *

     * - `account` cannot be the zero address.

     * - if `account` is a contract, it must implement the {IERC777Recipient}

     * interface.

     */
    function _mint(

        address account,

        uint256 amount,

        bytes memory userData,

        bytes memory operatorData

    ) internal virtual {
        _mint(account, amount, userData, operatorData, true);
    }

    /**

     * @dev Creates `amount` tokens and assigns them to `account`, increasing

     * the total supply.

     *

     * If `requireReceptionAck` is set to true, and if a send hook is

     * registered for `account`, the corresponding function will be called with

     * `operator`, `data` and `operatorData`.

     *

     * See {IERC777Sender} and {IERC777Recipient}.

     *

     * Emits {Minted} and {IERC20-Transfer} events.

     *

     * Requirements

     *

     * - `account` cannot be the zero address.

     * - if `account` is a contract, it must implement the {IERC777Recipient}

     * interface.

     */
    function _mint(

        address account,

        uint256 amount,

        bytes memory userData,

        bytes memory operatorData,

        bool requireReceptionAck

    ) internal virtual {
        require(account != address(0), "ERC777: mint to the zero address");

        address operator = _msgSender();

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

        // Update state variables
        _totalSupply += amount;
        _balances[account] += amount;

        _callTokensReceived(operator, address(0), account, amount, userData, operatorData, requireReceptionAck);

        emit Minted(operator, account, amount, userData, operatorData);
        emit Transfer(address(0), account, amount);
    }

    /**

     * @dev Send tokens

     * @param from address token holder address

     * @param to address recipient address

     * @param amount uint256 amount of tokens to transfer

     * @param userData bytes extra information provided by the token holder (if any)

     * @param operatorData bytes extra information provided by the operator (if any)

     * @param requireReceptionAck if true, contract recipients are required to implement ERC777TokensRecipient

     */
    function _send(

        address from,

        address to,

        uint256 amount,

        bytes memory userData,

        bytes memory operatorData,

        bool requireReceptionAck

    ) internal virtual {
        require(from != address(0), "ERC777: transfer from the zero address");
        require(to != address(0), "ERC777: transfer to the zero address");

        address operator = _msgSender();

        _callTokensToSend(operator, from, to, amount, userData, operatorData);

        _move(operator, from, to, amount, userData, operatorData);

        _callTokensReceived(operator, from, to, amount, userData, operatorData, requireReceptionAck);
    }

    /**

     * @dev Burn tokens

     * @param from address token holder address

     * @param amount uint256 amount of tokens to burn

     * @param data bytes extra information provided by the token holder

     * @param operatorData bytes extra information provided by the operator (if any)

     */
    function _burn(

        address from,

        uint256 amount,

        bytes memory data,

        bytes memory operatorData

    ) internal virtual {
        require(from != address(0), "ERC777: burn from the zero address");

        address operator = _msgSender();

        _callTokensToSend(operator, from, address(0), amount, data, operatorData);

        _beforeTokenTransfer(operator, from, address(0), amount);

        // Update state variables
        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC777: burn amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
        }
        _totalSupply -= amount;

        emit Burned(operator, from, amount, data, operatorData);
        emit Transfer(from, address(0), amount);
    }

    function _move(

        address operator,

        address from,

        address to,

        uint256 amount,

        bytes memory userData,

        bytes memory operatorData

    ) private {
        _beforeTokenTransfer(operator, from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC777: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
        }
        _balances[to] += amount;

        emit Sent(operator, from, to, amount, userData, operatorData);
        emit Transfer(from, to, amount);
    }

    /**

     * @dev See {ERC20-_approve}.

     *

     * Note that accounts cannot have allowance issued by their operators.

     */
    function _approve(

        address holder,

        address spender,

        uint256 value

    ) internal virtual {
        require(holder != address(0), "ERC777: approve from the zero address");
        require(spender != address(0), "ERC777: approve to the zero address");

        _allowances[holder][spender] = value;
        emit Approval(holder, spender, value);
    }

    /**

     * @dev Call from.tokensToSend() if the interface is registered

     * @param operator address operator requesting the transfer

     * @param from address token holder address

     * @param to address recipient address

     * @param amount uint256 amount of tokens to transfer

     * @param userData bytes extra information provided by the token holder (if any)

     * @param operatorData bytes extra information provided by the operator (if any)

     */
    function _callTokensToSend(

        address operator,

        address from,

        address to,

        uint256 amount,

        bytes memory userData,

        bytes memory operatorData

    ) private {
        address implementer = _ERC1820_REGISTRY.getInterfaceImplementer(from, _TOKENS_SENDER_INTERFACE_HASH);
        if (implementer != address(0)) {
            IERC777SenderUpgradeable(implementer).tokensToSend(operator, from, to, amount, userData, operatorData);
        }
    }

    /**

     * @dev Call to.tokensReceived() if the interface is registered. Reverts if the recipient is a contract but

     * tokensReceived() was not registered for the recipient

     * @param operator address operator requesting the transfer

     * @param from address token holder address

     * @param to address recipient address

     * @param amount uint256 amount of tokens to transfer

     * @param userData bytes extra information provided by the token holder (if any)

     * @param operatorData bytes extra information provided by the operator (if any)

     * @param requireReceptionAck if true, contract recipients are required to implement ERC777TokensRecipient

     */
    function _callTokensReceived(

        address operator,

        address from,

        address to,

        uint256 amount,

        bytes memory userData,

        bytes memory operatorData,

        bool requireReceptionAck

    ) private {
        address implementer = _ERC1820_REGISTRY.getInterfaceImplementer(to, _TOKENS_RECIPIENT_INTERFACE_HASH);
        if (implementer != address(0)) {
            IERC777RecipientUpgradeable(implementer).tokensReceived(operator, from, to, amount, userData, operatorData);
        } else if (requireReceptionAck) {
            require(!to.isContract(), "ERC777: token recipient contract has no implementer for ERC777TokensRecipient");
        }
    }

    /**

     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.

     *

     * Does not update the allowance amount in case of infinite allowance.

     * Revert if not enough allowance is available.

     *

     * Might emit an {IERC20-Approval} event.

     */
    function _spendAllowance(

        address owner,

        address spender,

        uint256 amount

    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC777: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**

     * @dev Hook that is called before any token transfer. This includes

     * calls to {send}, {transfer}, {operatorSend}, 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 operator,

        address from,

        address to,

        uint256 amount

    ) internal virtual {}

    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */
    uint256[41] private __gap;
}


// File @openzeppelin/contracts-upgradeable/token/ERC20/extensions/[email protected]


// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

/**

 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in

 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].

 *

 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by

 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't

 * need to send a transaction, and thus is not required to hold Ether at all.

 */
interface IERC20PermitUpgradeable {
    /**

     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,

     * given ``owner``'s signed approval.

     *

     * IMPORTANT: The same issues {IERC20-approve} has related to transaction

     * ordering also apply here.

     *

     * Emits an {Approval} event.

     *

     * Requirements:

     *

     * - `spender` cannot be the zero address.

     * - `deadline` must be a timestamp in the future.

     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`

     * over the EIP712-formatted function arguments.

     * - the signature must use ``owner``'s current nonce (see {nonces}).

     *

     * For more information on the signature format, see the

     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP

     * section].

     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**

     * @dev Returns the current nonce for `owner`. This value must be

     * included whenever a signature is generated for {permit}.

     *

     * Every successful call to {permit} increases ``owner``'s nonce by one. This

     * prevents a signature from being used multiple times.

     */
    function nonces(address owner) external view returns (uint256);

    /**

     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.

     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}


// File @openzeppelin/contracts-upgradeable/token/ERC20/utils/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;



/**

 * @title SafeERC20

 * @dev Wrappers around ERC20 operations that throw on failure (when the token

 * contract returns false). Tokens that return no value (and instead revert or

 * throw on failure) are also supported, non-reverting calls are assumed to be

 * successful.

 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,

 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.

 */
library SafeERC20Upgradeable {
    using AddressUpgradeable for address;

    function safeTransfer(

        IERC20Upgradeable token,

        address to,

        uint256 value

    ) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(

        IERC20Upgradeable 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(

        IERC20Upgradeable 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'
        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(

        IERC20Upgradeable token,

        address spender,

        uint256 value

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

    function safeDecreaseAllowance(

        IERC20Upgradeable token,

        address spender,

        uint256 value

    ) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - value;
            _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
        }
    }

    function safePermit(

        IERC20PermitUpgradeable token,

        address owner,

        address spender,

        uint256 value,

        uint256 deadline,

        uint8 v,

        bytes32 r,

        bytes32 s

    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**

     * @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(IERC20Upgradeable 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
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}


// File @openzeppelin/contracts-upgradeable/security/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;

/**

 * @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].

 */
abstract contract ReentrancyGuardUpgradeable is Initializable {
    // 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;

    function __ReentrancyGuard_init() internal onlyInitializing {
        __ReentrancyGuard_init_unchained();
    }

    function __ReentrancyGuard_init_unchained() internal onlyInitializing {
        _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 making it call a

     * `private` function that does the actual work.

     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be _NOT_ENTERED
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }

    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */
    uint256[49] private __gap;
}


// File @openzeppelin/contracts-upgradeable/access/[email protected]


// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;


/**

 * @dev Contract module which provides a basic access control mechanism, where

 * there is an account (an owner) that can be granted exclusive access to

 * specific functions.

 *

 * By default, the owner account will be the one that deploys the contract. This

 * can later be changed with {transferOwnership}.

 *

 * This module is used through inheritance. It will make available the modifier

 * `onlyOwner`, which can be applied to your functions to restrict their use to

 * the owner.

 */
abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;

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

    /**

     * @dev Initializes the contract setting the deployer as the initial owner.

     */
    function __Ownable_init() internal onlyInitializing {
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal onlyInitializing {
        _transferOwnership(_msgSender());
    }

    /**

     * @dev Throws if called by any account other than the owner.

     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**

     * @dev Returns the address of the current owner.

     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**

     * @dev Throws if the sender is not the owner.

     */
    function _checkOwner() internal view virtual {
        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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }

    /**

     * @dev Transfers ownership of the contract to a new account (`newOwner`).

     * Internal function without access restriction.

     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }

    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */
    uint256[49] private __gap;
}


// File @openzeppelin/contracts-upgradeable/access/[email protected]


// OpenZeppelin Contracts v4.4.1 (access/IAccessControl.sol)

pragma solidity ^0.8.0;

/**

 * @dev External interface of AccessControl declared to support ERC165 detection.

 */
interface IAccessControlUpgradeable {
    /**

     * @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-upgradeable/access/[email protected]


// OpenZeppelin Contracts v4.4.1 (access/IAccessControlEnumerable.sol)

pragma solidity ^0.8.0;

/**

 * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.

 */
interface IAccessControlEnumerableUpgradeable is IAccessControlUpgradeable {
    /**

     * @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-upgradeable/utils/math/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**

 * @dev Standard math utilities missing in the Solidity language.

 */
library MathUpgradeable {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**

     * @dev Returns the largest of two numbers.

     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**

     * @dev Returns the smallest of two numbers.

     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**

     * @dev Returns the average of two numbers. The result is rounded towards

     * zero.

     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**

     * @dev Returns the ceiling of the division of two numbers.

     *

     * This differs from standard division with `/` in that it rounds up instead

     * of rounding down.

     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**

     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0

     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)

     * with further edits by Uniswap Labs also under MIT license.

     */
    function mulDiv(

        uint256 x,

        uint256 y,

        uint256 denominator

    ) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                return prod0 / denominator;
            }

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

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

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;



            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such

            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for

            // four bits. That is, denominator * inv = 1 mod 2^4.

            uint256 inverse = (3 * denominator) ^ 2;



            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works

            // in modular arithmetic, doubling the correct bits in each step.

            inverse *= 2 - denominator * inverse; // inverse mod 2^8

            inverse *= 2 - denominator * inverse; // inverse mod 2^16

            inverse *= 2 - denominator * inverse; // inverse mod 2^32

            inverse *= 2 - denominator * inverse; // inverse mod 2^64

            inverse *= 2 - denominator * inverse; // inverse mod 2^128

            inverse *= 2 - denominator * inverse; // inverse mod 2^256



            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.

            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is

            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1

            // is no longer required.

            result = prod0 * inverse;

            return result;

        }

    }



    /**

     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.

     */

    function mulDiv(

        uint256 x,

        uint256 y,

        uint256 denominator,

        Rounding rounding

    ) internal pure returns (uint256) {

        uint256 result = mulDiv(x, y, denominator);

        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {

            result += 1;

        }

        return result;

    }



    /**

     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.

     *

     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).

     */

    function sqrt(uint256 a) internal pure returns (uint256) {

        if (a == 0) {

            return 0;

        }



        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.

        //

        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have

        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.

        //

        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`

        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`

        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`

        //

        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.

        uint256 result = 1 << (log2(a) >> 1);



        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,

        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at

        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision

        // into the expected uint128 result.

        unchecked {

            result = (result + a / result) >> 1;

            result = (result + a / result) >> 1;

            result = (result + a / result) >> 1;

            result = (result + a / result) >> 1;

            result = (result + a / result) >> 1;

            result = (result + a / result) >> 1;

            result = (result + a / result) >> 1;

            return min(result, a / result);

        }

    }



    /**

     * @notice Calculates sqrt(a), following the selected rounding direction.

     */

    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {

        unchecked {

            uint256 result = sqrt(a);

            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);

        }

    }



    /**

     * @dev Return the log in base 2, rounded down, of a positive value.

     * Returns 0 if given 0.

     */

    function log2(uint256 value) internal pure returns (uint256) {

        uint256 result = 0;

        unchecked {

            if (value >> 128 > 0) {

                value >>= 128;

                result += 128;

            }

            if (value >> 64 > 0) {

                value >>= 64;

                result += 64;

            }

            if (value >> 32 > 0) {

                value >>= 32;

                result += 32;

            }

            if (value >> 16 > 0) {

                value >>= 16;

                result += 16;

            }

            if (value >> 8 > 0) {

                value >>= 8;

                result += 8;

            }

            if (value >> 4 > 0) {

                value >>= 4;

                result += 4;

            }

            if (value >> 2 > 0) {

                value >>= 2;

                result += 2;

            }

            if (value >> 1 > 0) {

                result += 1;

            }

        }

        return result;

    }



    /**

     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.

     * Returns 0 if given 0.

     */

    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {

        unchecked {

            uint256 result = log2(value);

            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);

        }

    }



    /**

     * @dev Return the log in base 10, rounded down, of a positive value.

     * Returns 0 if given 0.

     */

    function log10(uint256 value) internal pure returns (uint256) {

        uint256 result = 0;

        unchecked {

            if (value >= 10**64) {

                value /= 10**64;

                result += 64;

            }

            if (value >= 10**32) {

                value /= 10**32;

                result += 32;

            }

            if (value >= 10**16) {

                value /= 10**16;

                result += 16;

            }

            if (value >= 10**8) {

                value /= 10**8;

                result += 8;

            }

            if (value >= 10**4) {

                value /= 10**4;

                result += 4;

            }

            if (value >= 10**2) {

                value /= 10**2;

                result += 2;

            }

            if (value >= 10**1) {

                result += 1;

            }

        }

        return result;

    }



    /**

     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.

     * Returns 0 if given 0.

     */

    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {

        unchecked {

            uint256 result = log10(value);

            return result + (rounding == Rounding.Up && 10**result < value ? 1 : 0);

        }

    }



    /**

     * @dev Return the log in base 256, rounded down, of a positive value.

     * Returns 0 if given 0.

     *

     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.

     */

    function log256(uint256 value) internal pure returns (uint256) {

        uint256 result = 0;

        unchecked {

            if (value >> 128 > 0) {

                value >>= 128;

                result += 16;

            }

            if (value >> 64 > 0) {

                value >>= 64;

                result += 8;

            }

            if (value >> 32 > 0) {

                value >>= 32;

                result += 4;

            }

            if (value >> 16 > 0) {

                value >>= 16;

                result += 2;

            }

            if (value >> 8 > 0) {

                result += 1;

            }

        }

        return result;

    }



    /**

     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.

     * Returns 0 if given 0.

     */

    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {

        unchecked {

            uint256 result = log256(value);

            return result + (rounding == Rounding.Up && 1 << (result * 8) < value ? 1 : 0);

        }

    }

}





// File @openzeppelin/contracts-upgradeable/utils/StringsUpgradeable[email protected]





// OpenZeppelin Contracts (last updated v4.8.0) (utils/Strings.sol)



pragma solidity ^0.8.0;



/**

 * @dev String operations.

 */

library StringsUpgradeable {

    bytes16 private constant _SYMBOLS = "0123456789abcdef";

    uint8 private constant _ADDRESS_LENGTH = 20;



    /**

     * @dev Converts a `uint256` to its ASCII `string` decimal representation.

     */

    function toString(uint256 value) internal pure returns (string memory) {

        unchecked {

            uint256 length = MathUpgradeable.log10(value) + 1;

            string memory buffer = new string(length);

            uint256 ptr;

            /// @solidity memory-safe-assembly

            assembly {

                ptr := add(buffer, add(32, length))

            }

            while (true) {

                ptr--;

                /// @solidity memory-safe-assembly

                assembly {

                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))

                }

                value /= 10;

                if (value == 0) break;

            }

            return buffer;

        }

    }



    /**

     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.

     */

    function toHexString(uint256 value) internal pure returns (string memory) {

        unchecked {

            return toHexString(value, MathUpgradeable.log256(value) + 1);

        }

    }



    /**

     * @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] = _SYMBOLS[value & 0xf];

            value >>= 4;

        }

        require(value == 0, "Strings: hex length insufficient");

        return string(buffer);

    }



    /**

     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.

     */

    function toHexString(address addr) internal pure returns (string memory) {

        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);

    }

}





// File @openzeppelin/contracts-upgradeable/utils/introspection/IERC165Upgradeable[email protected]





// 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 IERC165Upgradeable {

    /**

     * @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-upgradeable/utils/introspection/ERC165Upgradeable[email protected]





// 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 ERC165Upgradeable is Initializable, IERC165Upgradeable {

    function __ERC165_init() internal onlyInitializing {

    }



    function __ERC165_init_unchained() internal onlyInitializing {

    }

    /**

     * @dev See {IERC165-supportsInterface}.

     */

    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {

        return interfaceId == type(IERC165Upgradeable).interfaceId;

    }



    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */

    uint256[50] private __gap;

}





// File @openzeppelin/contracts-upgradeable/access/AccessControlUpgradeable[email protected]





// OpenZeppelin Contracts (last updated v4.8.0) (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 AccessControlUpgradeable is Initializable, ContextUpgradeable, IAccessControlUpgradeable, ERC165Upgradeable {

    function __AccessControl_init() internal onlyInitializing {

    }



    function __AccessControl_init_unchained() internal onlyInitializing {

    }

    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);
        _;
    }

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControlUpgradeable).interfaceId || super.supportsInterface(interfaceId);
    }

    /**

     * @dev Returns `true` if `account` has been granted `role`.

     */
    function hasRole(bytes32 role, address account) public view virtual override returns (bool) {
        return _roles[role].members[account];
    }

    /**

     * @dev Revert with a standard message if `_msgSender()` is missing `role`.

     * Overriding this function changes the behavior of the {onlyRole} modifier.

     *

     * Format of the revert message is described in {_checkRole}.

     *

     * _Available since v4.6._

     */
    function _checkRole(bytes32 role) internal view virtual {
        _checkRole(role, _msgSender());
    }

    /**

     * @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 virtual {
        if (!hasRole(role, account)) {
            revert(
                string(
                    abi.encodePacked(

                        "AccessControl: account ",

                        StringsUpgradeable.toHexString(account),
                        " is missing role ",
                        StringsUpgradeable.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 virtual 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.

     *

     * May emit a {RoleGranted} event.

     */
    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.

     *

     * May emit a {RoleRevoked} event.

     */
    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`.

     *

     * May emit a {RoleRevoked} event.

     */
    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.

     *

     * May emit a {RoleGranted} event.

     *

     * [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.

     *

     * May emit a {RoleGranted} event.

     */
    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.

     *

     * May emit a {RoleRevoked} event.

     */
    function _revokeRole(bytes32 role, address account) internal virtual {
        if (hasRole(role, account)) {
            _roles[role].members[account] = false;
            emit RoleRevoked(role, account, _msgSender());
        }
    }

    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */
    uint256[49] private __gap;
}


// File @openzeppelin/contracts-upgradeable/utils/structs/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (utils/structs/EnumerableSet.sol)
// This file was procedurally generated from scripts/generate/templates/EnumerableSet.js.

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.

 *

 * [WARNING]

 * ====

 * Trying to delete such a structure from storage will likely result in data corruption, rendering the structure

 * unusable.

 * See https://github.com/ethereum/solidity/pull/11843[ethereum/solidity#11843] for more info.

 *

 * In order to clean an EnumerableSet, you can either remove all elements one by one or create a fresh instance using an

 * array of EnumerableSet.

 * ====

 */
library EnumerableSetUpgradeable {
    // 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) {
        bytes32[] memory store = _values(set._inner);
        bytes32[] memory result;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }

    // 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;

        /// @solidity memory-safe-assembly
        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 in 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;

        /// @solidity memory-safe-assembly
        assembly {
            result := store
        }

        return result;
    }
}


// File @openzeppelin/contracts-upgradeable/access/[email protected]


// OpenZeppelin Contracts (last updated v4.5.0) (access/AccessControlEnumerable.sol)

pragma solidity ^0.8.0;




/**

 * @dev Extension of {AccessControl} that allows enumerating the members of each role.

 */
abstract contract AccessControlEnumerableUpgradeable is Initializable, IAccessControlEnumerableUpgradeable, AccessControlUpgradeable {
    function __AccessControlEnumerable_init() internal onlyInitializing {
    }

    function __AccessControlEnumerable_init_unchained() internal onlyInitializing {
    }
    using EnumerableSetUpgradeable for EnumerableSetUpgradeable.AddressSet;

    mapping(bytes32 => EnumerableSetUpgradeable.AddressSet) private _roleMembers;

    /**

     * @dev See {IERC165-supportsInterface}.

     */
    function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
        return interfaceId == type(IAccessControlEnumerableUpgradeable).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 virtual 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 virtual 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);
    }

    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */
    uint256[49] private __gap;
}


// File @openzeppelin/contracts-upgradeable/interfaces/[email protected]


// OpenZeppelin Contracts (last updated v4.5.0) (interfaces/draft-IERC1822.sol)

pragma solidity ^0.8.0;

/**

 * @dev ERC1822: Universal Upgradeable Proxy Standard (UUPS) documents a method for upgradeability through a simplified

 * proxy whose upgrades are fully controlled by the current implementation.

 */
interface IERC1822ProxiableUpgradeable {
    /**

     * @dev Returns the storage slot that the proxiable contract assumes is being used to store the implementation

     * address.

     *

     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks

     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this

     * function revert if invoked through a proxy.

     */
    function proxiableUUID() external view returns (bytes32);
}


// File @openzeppelin/contracts-upgradeable/proxy/beacon/[email protected]


// OpenZeppelin Contracts v4.4.1 (proxy/beacon/IBeacon.sol)

pragma solidity ^0.8.0;

/**

 * @dev This is the interface that {BeaconProxy} expects of its beacon.

 */
interface IBeaconUpgradeable {
    /**

     * @dev Must return an address that can be used as a delegate call target.

     *

     * {BeaconProxy} will check that this address is a contract.

     */
    function implementation() external view returns (address);
}


// File @openzeppelin/contracts-upgradeable/utils/[email protected]


// OpenZeppelin Contracts (last updated v4.7.0) (utils/StorageSlot.sol)

pragma solidity ^0.8.0;

/**

 * @dev Library for reading and writing primitive types to specific storage slots.

 *

 * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.

 * This library helps with reading and writing to such slots without the need for inline assembly.

 *

 * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.

 *

 * Example usage to set ERC1967 implementation slot:

 * ```

 * contract ERC1967 {

 *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

 *

 *     function _getImplementation() internal view returns (address) {

 *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;

 *     }

 *

 *     function _setImplementation(address newImplementation) internal {

 *         require(Address.isContract(newImplementation), "ERC1967: new implementation is not a contract");

 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;

 *     }

 * }

 * ```

 *

 * _Available since v4.1 for `address`, `bool`, `bytes32`, and `uint256`._

 */
library StorageSlotUpgradeable {
    struct AddressSlot {
        address value;
    }

    struct BooleanSlot {
        bool value;
    }

    struct Bytes32Slot {
        bytes32 value;
    }

    struct Uint256Slot {
        uint256 value;
    }

    /**

     * @dev Returns an `AddressSlot` with member `value` located at `slot`.

     */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**

     * @dev Returns an `BooleanSlot` with member `value` located at `slot`.

     */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**

     * @dev Returns an `Bytes32Slot` with member `value` located at `slot`.

     */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**

     * @dev Returns an `Uint256Slot` with member `value` located at `slot`.

     */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }
}


// File @openzeppelin/contracts-upgradeable/proxy/ERC1967/[email protected]


// OpenZeppelin Contracts (last updated v4.5.0) (proxy/ERC1967/ERC1967Upgrade.sol)

pragma solidity ^0.8.2;





/**

 * @dev This abstract contract provides getters and event emitting update functions for

 * https://eips.ethereum.org/EIPS/eip-1967[EIP1967] slots.

 *

 * _Available since v4.1._

 *

 * @custom:oz-upgrades-unsafe-allow delegatecall

 */
abstract contract ERC1967UpgradeUpgradeable is Initializable {
    function __ERC1967Upgrade_init() internal onlyInitializing {
    }

    function __ERC1967Upgrade_init_unchained() internal onlyInitializing {
    }
    // This is the keccak-256 hash of "eip1967.proxy.rollback" subtracted by 1
    bytes32 private constant _ROLLBACK_SLOT = 0x4910fdfa16fed3260ed0e7147f7cc6da11a60208b5b9406d12a635614ffd9143;

    /**

     * @dev Storage slot with the address of the current implementation.

     * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is

     * validated in the constructor.

     */
    bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

    /**

     * @dev Emitted when the implementation is upgraded.

     */
    event Upgraded(address indexed implementation);

    /**

     * @dev Returns the current implementation address.

     */
    function _getImplementation() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_IMPLEMENTATION_SLOT).value;
    }

    /**

     * @dev Stores a new address in the EIP1967 implementation slot.

     */
    function _setImplementation(address newImplementation) private {
        require(AddressUpgradeable.isContract(newImplementation), "ERC1967: new implementation is not a contract");
        StorageSlotUpgradeable.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
    }

    /**

     * @dev Perform implementation upgrade

     *

     * Emits an {Upgraded} event.

     */
    function _upgradeTo(address newImplementation) internal {
        _setImplementation(newImplementation);
        emit Upgraded(newImplementation);
    }

    /**

     * @dev Perform implementation upgrade with additional setup call.

     *

     * Emits an {Upgraded} event.

     */
    function _upgradeToAndCall(

        address newImplementation,

        bytes memory data,

        bool forceCall

    ) internal {
        _upgradeTo(newImplementation);
        if (data.length > 0 || forceCall) {
            _functionDelegateCall(newImplementation, data);
        }
    }

    /**

     * @dev Perform implementation upgrade with security checks for UUPS proxies, and additional setup call.

     *

     * Emits an {Upgraded} event.

     */
    function _upgradeToAndCallUUPS(

        address newImplementation,

        bytes memory data,

        bool forceCall

    ) internal {
        // Upgrades from old implementations will perform a rollback test. This test requires the new
        // implementation to upgrade back to the old, non-ERC1822 compliant, implementation. Removing
        // this special case will break upgrade paths from old UUPS implementation to new ones.
        if (StorageSlotUpgradeable.getBooleanSlot(_ROLLBACK_SLOT).value) {
            _setImplementation(newImplementation);
        } else {
            try IERC1822ProxiableUpgradeable(newImplementation).proxiableUUID() returns (bytes32 slot) {
                require(slot == _IMPLEMENTATION_SLOT, "ERC1967Upgrade: unsupported proxiableUUID");
            } catch {
                revert("ERC1967Upgrade: new implementation is not UUPS");
            }
            _upgradeToAndCall(newImplementation, data, forceCall);
        }
    }

    /**

     * @dev Storage slot with the admin of the contract.

     * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is

     * validated in the constructor.

     */
    bytes32 internal constant _ADMIN_SLOT = 0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

    /**

     * @dev Emitted when the admin account has changed.

     */
    event AdminChanged(address previousAdmin, address newAdmin);

    /**

     * @dev Returns the current admin.

     */
    function _getAdmin() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_ADMIN_SLOT).value;
    }

    /**

     * @dev Stores a new address in the EIP1967 admin slot.

     */
    function _setAdmin(address newAdmin) private {
        require(newAdmin != address(0), "ERC1967: new admin is the zero address");
        StorageSlotUpgradeable.getAddressSlot(_ADMIN_SLOT).value = newAdmin;
    }

    /**

     * @dev Changes the admin of the proxy.

     *

     * Emits an {AdminChanged} event.

     */
    function _changeAdmin(address newAdmin) internal {
        emit AdminChanged(_getAdmin(), newAdmin);
        _setAdmin(newAdmin);
    }

    /**

     * @dev The storage slot of the UpgradeableBeacon contract which defines the implementation for this proxy.

     * This is bytes32(uint256(keccak256('eip1967.proxy.beacon')) - 1)) and is validated in the constructor.

     */
    bytes32 internal constant _BEACON_SLOT = 0xa3f0ad74e5423aebfd80d3ef4346578335a9a72aeaee59ff6cb3582b35133d50;

    /**

     * @dev Emitted when the beacon is upgraded.

     */
    event BeaconUpgraded(address indexed beacon);

    /**

     * @dev Returns the current beacon.

     */
    function _getBeacon() internal view returns (address) {
        return StorageSlotUpgradeable.getAddressSlot(_BEACON_SLOT).value;
    }

    /**

     * @dev Stores a new beacon in the EIP1967 beacon slot.

     */
    function _setBeacon(address newBeacon) private {
        require(AddressUpgradeable.isContract(newBeacon), "ERC1967: new beacon is not a contract");
        require(
            AddressUpgradeable.isContract(IBeaconUpgradeable(newBeacon).implementation()),
            "ERC1967: beacon implementation is not a contract"
        );
        StorageSlotUpgradeable.getAddressSlot(_BEACON_SLOT).value = newBeacon;
    }

    /**

     * @dev Perform beacon upgrade with additional setup call. Note: This upgrades the address of the beacon, it does

     * not upgrade the implementation contained in the beacon (see {UpgradeableBeacon-_setImplementation} for that).

     *

     * Emits a {BeaconUpgraded} event.

     */
    function _upgradeBeaconToAndCall(

        address newBeacon,

        bytes memory data,

        bool forceCall

    ) internal {
        _setBeacon(newBeacon);
        emit BeaconUpgraded(newBeacon);
        if (data.length > 0 || forceCall) {
            _functionDelegateCall(IBeaconUpgradeable(newBeacon).implementation(), data);
        }
    }

    /**

     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],

     * but performing a delegate call.

     *

     * _Available since v3.4._

     */
    function _functionDelegateCall(address target, bytes memory data) private returns (bytes memory) {
        require(AddressUpgradeable.isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return AddressUpgradeable.verifyCallResult(success, returndata, "Address: low-level delegate call failed");
    }

    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */
    uint256[50] private __gap;
}


// File @openzeppelin/contracts-upgradeable/proxy/utils/[email protected]


// OpenZeppelin Contracts (last updated v4.8.0) (proxy/utils/UUPSUpgradeable.sol)

pragma solidity ^0.8.0;



/**

 * @dev An upgradeability mechanism designed for UUPS proxies. The functions included here can perform an upgrade of an

 * {ERC1967Proxy}, when this contract is set as the implementation behind such a proxy.

 *

 * A security mechanism ensures that an upgrade does not turn off upgradeability accidentally, although this risk is

 * reinstated if the upgrade retains upgradeability but removes the security mechanism, e.g. by replacing

 * `UUPSUpgradeable` with a custom implementation of upgrades.

 *

 * The {_authorizeUpgrade} function must be overridden to include access restriction to the upgrade mechanism.

 *

 * _Available since v4.1._

 */
abstract contract UUPSUpgradeable is Initializable, IERC1822ProxiableUpgradeable, ERC1967UpgradeUpgradeable {
    function __UUPSUpgradeable_init() internal onlyInitializing {
    }

    function __UUPSUpgradeable_init_unchained() internal onlyInitializing {
    }
    /// @custom:oz-upgrades-unsafe-allow state-variable-immutable state-variable-assignment
    address private immutable __self = address(this);

    /**

     * @dev Check that the execution is being performed through a delegatecall call and that the execution context is

     * a proxy contract with an implementation (as defined in ERC1967) pointing to self. This should only be the case

     * for UUPS and transparent proxies that are using the current contract as their implementation. Execution of a

     * function through ERC1167 minimal proxies (clones) would not normally pass this test, but is not guaranteed to

     * fail.

     */
    modifier onlyProxy() {
        require(address(this) != __self, "Function must be called through delegatecall");
        require(_getImplementation() == __self, "Function must be called through active proxy");
        _;
    }

    /**

     * @dev Check that the execution is not being performed through a delegate call. This allows a function to be

     * callable on the implementing contract but not through proxies.

     */
    modifier notDelegated() {
        require(address(this) == __self, "UUPSUpgradeable: must not be called through delegatecall");
        _;
    }

    /**

     * @dev Implementation of the ERC1822 {proxiableUUID} function. This returns the storage slot used by the

     * implementation. It is used to validate the implementation's compatibility when performing an upgrade.

     *

     * IMPORTANT: A proxy pointing at a proxiable contract should not be considered proxiable itself, because this risks

     * bricking a proxy that upgrades to it, by delegating to itself until out of gas. Thus it is critical that this

     * function revert if invoked through a proxy. This is guaranteed by the `notDelegated` modifier.

     */
    function proxiableUUID() external view virtual override notDelegated returns (bytes32) {
        return _IMPLEMENTATION_SLOT;
    }

    /**

     * @dev Upgrade the implementation of the proxy to `newImplementation`.

     *

     * Calls {_authorizeUpgrade}.

     *

     * Emits an {Upgraded} event.

     */
    function upgradeTo(address newImplementation) external virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, new bytes(0), false);
    }

    /**

     * @dev Upgrade the implementation of the proxy to `newImplementation`, and subsequently execute the function call

     * encoded in `data`.

     *

     * Calls {_authorizeUpgrade}.

     *

     * Emits an {Upgraded} event.

     */
    function upgradeToAndCall(address newImplementation, bytes memory data) external payable virtual onlyProxy {
        _authorizeUpgrade(newImplementation);
        _upgradeToAndCallUUPS(newImplementation, data, true);
    }

    /**

     * @dev Function that should revert when `msg.sender` is not authorized to upgrade the contract. Called by

     * {upgradeTo} and {upgradeToAndCall}.

     *

     * Normally, this function will use an xref:access.adoc[access control] modifier such as {Ownable-onlyOwner}.

     *

     * ```solidity

     * function _authorizeUpgrade(address) internal override onlyOwner {}

     * ```

     */
    function _authorizeUpgrade(address newImplementation) internal virtual;

    /**

     * @dev This empty reserved space is put in place to allow future versions to add new

     * variables without shifting down storage in the inheritance chain.

     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps

     */
    uint256[50] private __gap;
}


// File @openzeppelin/contracts-upgradeable/utils/math/[email protected]


// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**

 * @dev Wrappers over Solidity's arithmetic operations.

 *

 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler

 * now has built in overflow checking.

 */
library SafeMathUpgradeable {
    /**

     * @dev Returns the addition of two unsigned integers, with an overflow flag.

     *

     * _Available since v3.4._

     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**

     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.

     *

     * _Available since v3.4._

     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**

     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.

     *

     * _Available since v3.4._

     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // 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 (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**

     * @dev Returns the division of two unsigned integers, with a division by zero flag.

     *

     * _Available since v3.4._

     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**

     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.

     *

     * _Available since v3.4._

     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**

     * @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) {
        return a + b;
    }

    /**

     * @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 a - b;
    }

    /**

     * @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) {
        return a * b;
    }

    /**

     * @dev Returns the integer division of two unsigned integers, reverting on

     * division by zero. The result is rounded towards zero.

     *

     * Counterpart to Solidity's `/` operator.

     *

     * Requirements:

     *

     * - The divisor cannot be zero.

     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**

     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),

     * reverting 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 a % b;
    }

    /**

     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on

     * overflow (when the result is negative).

     *

     * CAUTION: This function is deprecated because it requires allocating memory for the error

     * message unnecessarily. For custom revert reasons use {trySub}.

     *

     * Counterpart to Solidity's `-` operator.

     *

     * Requirements:

     *

     * - Subtraction cannot overflow.

     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**

     * @dev Returns the integer division of two unsigned integers, reverting 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) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**

     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),

     * reverting with custom message when dividing by zero.

     *

     * CAUTION: This function is deprecated because it requires allocating memory for the error

     * message unnecessarily. For custom revert reasons use {tryMod}.

     *

     * 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) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}


// File contracts/logt-unified-vesting-v2.sol

// contracts/TokenVesting.sol

pragma solidity ^0.8.10;

// import "@openzeppelin/contracts-upgradeable/token/ERC20/IERC20Upgradeable.sol";









// import "hardhat/console.sol";
/**

 * @title TokenVesting

 */
contract LOGT_Unified_Vesting_V2 is 
    Initializable,
    OwnableUpgradeable,
    AccessControlEnumerableUpgradeable,
    ERC777Upgradeable,
    UUPSUpgradeable,
    ReentrancyGuardUpgradeable {
    
    bytes32 public constant MANAGER_ROLE = keccak256("MANAGER_ROLE");

    using SafeMathUpgradeable for uint256;
    using SafeERC20Upgradeable for IERC20Upgradeable;
    
    struct VestingSchedule{
        bool initialized;
        // beneficiary of tokens after they are released
        address  beneficiary;
        // cliff period in seconds
        uint256  cliff;
        // start time of the vesting period
        uint256  start;
        // duration of the vesting period in seconds
        uint256  duration;
        // duration of a slice period for the vesting in seconds
        uint256 slicePeriodSeconds;
        // whether or not the vesting is revocable
        bool  revocable;
        // total amount of tokens to be released at the end of the vesting
        uint256 amountTotal;
        // amount of tokens released
        uint256  released;
        // whether or not the vesting has been revoked
        bool revoked;
    }

    // address of the ERC20 token
    // IERC20Upgradeable private _token;

    bytes32[] private vestingSchedulesIds;
    mapping(bytes32 => VestingSchedule) private vestingSchedules;
    uint256 private vestingSchedulesTotalAmount;
    mapping(address => uint256) private holdersVestingCount;

    // uint256 private _vestedTokenPool;

    event Released(uint256 amount);
    event Revoked(bytes32);
    event VestingCreated(bytes32, address, uint256);

    /**

    * @dev Reverts if no vesting schedule matches the passed identifier.

    */
    modifier onlyIfVestingScheduleExists(bytes32 vestingScheduleId) {
        require(vestingSchedules[vestingScheduleId].initialized == true, "not intialized");
        _;
    }

    /**

    * @dev Reverts if the vesting schedule does not exist or has been revoked.

    */
    modifier onlyIfVestingScheduleNotRevoked(bytes32 vestingScheduleId) {
        require(vestingSchedules[vestingScheduleId].initialized == true, "not intialized");
        require(vestingSchedules[vestingScheduleId].revoked == false, "already revoked");
        _;
    }

    // from now on, contract update prohibited
    bool public constant _upgradeLocked = true;

    /// @custom:oz-upgrades-unsafe-allow constructor
    constructor() {
        _disableInitializers();
    }

    /**

     * @dev Creates a vesting contract.

     */
    // function initialize(address token_) public initializer {
    function initialize(
        string memory name,
        string memory symbol,
        uint256 initialSupply) public initializer {
        __Ownable_init();
        __UUPSUpgradeable_init();
        __ReentrancyGuard_init();
        // require(token_ != address(0x0), "token address is 0x");
        //  _token = IERC20Upgradeable(token_);

        __ERC777_init(name, symbol, new address[](0));
        _mint(_msgSender(), initialSupply, "", "");

        _setupRole(DEFAULT_ADMIN_ROLE, _msgSender());
        _setupRole(MANAGER_ROLE, _msgSender());
    }

    receive() external payable {}

    fallback() external payable {}

    /**

    * @dev Returns the number of vesting schedules associated to a beneficiary.

    * @return the number of vesting schedules

    */
    function getVestingSchedulesCountByBeneficiary(address _beneficiary)
    public
    view
    returns(uint256){
        return holdersVestingCount[_beneficiary];
    }

    /**

    * @dev Returns the vesting schedule id at the given index.

    * @return the vesting id

    */
    function getVestingIdAtIndex(uint256 index)
    external
    view
    returns(bytes32){
        require(index < getVestingSchedulesCount(), "index out of bounds");
        return vestingSchedulesIds[index];
    }

    /**

    * @notice Returns the vesting schedule information for a given holder and index.

    * @return the vesting schedule structure information

    */
    function getVestingScheduleByAddressAndIndex(address holder, uint256 index)
    public
    view
    returns(VestingSchedule memory){
        return getVestingSchedule(computeVestingScheduleIdForAddressAndIndex(holder, index));
    }


    /**

    * @notice Returns the total amount of vesting schedules.

    * @return the total amount of vesting schedules

    */
    function getVestingSchedulesTotalAmount()
    external
    view
    returns(uint256){
        return vestingSchedulesTotalAmount;
    }

    // /**
    // * @dev Returns the address of the ERC20 token managed by the vesting contract.
    // */
    // function getToken()
    // external
    // view
    // returns(address){
    //     return address(_token);
    // }

    /**

    * @notice Creates a new vesting schedule for a beneficiary.

    * @param _beneficiary address of the beneficiary to whom vested tokens are transferred

    * @param _start start time of the vesting period

    * @param _cliff duration in seconds of the cliff in which tokens will begin to vest

    * @param _duration duration in seconds of the period in which the tokens will vest

    * @param _slicePeriodSeconds duration of a slice period for the vesting in seconds

    * @param _revocable whether the vesting is revocable or not

    * @param _amount total amount of tokens to be released at the end of the vesting

    */
    function createVestingSchedule(

        address _beneficiary,

        uint256 _start,

        uint256 _cliff,

        uint256 _duration,

        uint256 _slicePeriodSeconds,

        bool _revocable,

        uint256 _amount

    )
        public
        {
        // require(
        //     this.getWithdrawableAmount() >= _amount,
        //     "cannot create vesting schedule because not sufficient tokens"
        // );
        require(hasRole(MANAGER_ROLE, _msgSender()), "unauthorized");
        require(_duration > 0, "duration must be > 0");
        require(_amount > 0, "amount must be > 0");
        require(_cliff <= _duration, "invalid cliff");
        require(_slicePeriodSeconds >= 1, "slicePeriodSeconds must be >= 1");

        bytes32 vestingScheduleId = this.computeNextVestingScheduleIdForHolder(_beneficiary);
        uint256 cliff = _start.add(_cliff);
        vestingSchedules[vestingScheduleId] = VestingSchedule(

            true,

            _beneficiary,

            cliff,

            _start,

            _duration,

            _slicePeriodSeconds,

            _revocable,

            _amount,

            0,

            false

        );
        vestingSchedulesTotalAmount = vestingSchedulesTotalAmount.add(_amount);
        vestingSchedulesIds.push(vestingScheduleId);
        uint256 currentVestingCount = holdersVestingCount[_beneficiary];
        holdersVestingCount[_beneficiary] = currentVestingCount.add(1);

        // todo: add event emit
        emit VestingCreated(vestingScheduleId, _beneficiary, _amount);
    }

    /**

    * @notice Revokes the vesting schedule for given identifier.

    * @param vestingScheduleId the vesting schedule identifier

    */
    function revoke(bytes32 vestingScheduleId)
        public
        onlyIfVestingScheduleNotRevoked(vestingScheduleId){
        require(hasRole(MANAGER_ROLE, _msgSender()), "unauthorized");
        VestingSchedule storage vestingSchedule = vestingSchedules[vestingScheduleId];
        require(vestingSchedule.revocable == true, "vesting is not revocable");
        // uint256 vestedAmount = _computeReleasableAmount(vestingSchedule);
        // if(vestedAmount > 0){
        //     release(vestingScheduleId, vestedAmount);
        // }
        uint256 unreleased = vestingSchedule.amountTotal.sub(vestingSchedule.released);
        vestingSchedulesTotalAmount = vestingSchedulesTotalAmount.sub(unreleased);
        vestingSchedule.revoked = true;

        // todo: add event emit
        emit Revoked(vestingScheduleId);
    }

    /**

    * @notice Withdraw the specified amount if possible.

    * @param amount the amount to withdraw

    */
    // function withdraw(uint256 amount)
    //     public
    //     nonReentrant
    //     onlyOwner{
    //     require(this.getWithdrawableAmount() >= amount, "not enough withdrawable funds");
    //     // _token.safeTransfer(owner(), amount);

    //     // todo: add event emit
    // }

    // /**
    // * @notice Release vested amount of tokens.
    // * @param vestingScheduleId the vesting schedule identifier
    // * @param amount the amount to release
    // */
    // function release(
    //     bytes32 vestingScheduleId,
    //     uint256 amount
    // )
    //     public
    //     nonReentrant
    //     onlyIfVestingScheduleNotRevoked(vestingScheduleId){
    //     VestingSchedule storage vestingSchedule = vestingSchedules[vestingScheduleId];
    //     bool isBeneficiary = msg.sender == vestingSchedule.beneficiary;
    //     bool isOwner = msg.sender == owner();
    //     require(
    //         isBeneficiary || isOwner,
    //         "only beneficiary and owner can release vested tokens"
    //     );
    //     uint256 vestedAmount = _computeReleasableAmount(vestingSchedule);
    //     require(vestedAmount >= amount, "cannot release tokens, not enough vested tokens");
    //     vestingSchedule.released = vestingSchedule.released.add(amount);
    //     address payable beneficiaryPayable = payable(vestingSchedule.beneficiary);
    //     vestingSchedulesTotalAmount = vestingSchedulesTotalAmount.sub(amount);
    //     _token.safeTransfer(beneficiaryPayable, amount);
    // }

    /**

    * @dev Returns the number of vesting schedules managed by this contract.

    * @return the number of vesting schedules

    */
    function getVestingSchedulesCount()
        public
        view
        returns(uint256){
        return vestingSchedulesIds.length;
    }

    /**

    * @notice Computes the vested amount of tokens for the given vesting schedule identifier.

    * @return the vested amount

    */
    function computeReleasableAmount(bytes32 vestingScheduleId)
        public
        onlyIfVestingScheduleNotRevoked(vestingScheduleId)
        view
        returns(uint256){
        VestingSchedule storage vestingSchedule = vestingSchedules[vestingScheduleId];
        return _computeReleasableAmount(vestingSchedule);
    }

    function computeLockedAmount(address holder)
        public
        view
        returns(uint256) {
        uint count = getVestingSchedulesCountByBeneficiary(holder);
        require(count <= getVestingSchedulesCount(), "index out of bounds");
        uint totalLocked = 0;
        for (uint i = 0; i < count; i++) {
            VestingSchedule memory vestingSchedule = getVestingScheduleByAddressAndIndex(holder, i);
            
            uint256 lockedAmount = _computeLockedAmount(vestingSchedule);
            totalLocked = totalLocked.add(lockedAmount);
        }

        return totalLocked;
    }

    /**

    * @notice Returns the vesting schedule information for a given identifier.

    * @return the vesting schedule structure information

    */
    function getVestingSchedule(bytes32 vestingScheduleId)
        public
        view
        returns(VestingSchedule memory){
        return vestingSchedules[vestingScheduleId];
    }

    /**

    * @dev Returns the amount of tokens that can be withdrawn by the owner.

    * @return the amount of tokens

    */
    // function getWithdrawableAmount()
    //     public
    //     view
    //     returns(uint256){
    //     // return _token.balanceOf(address(this)).sub(vestingSchedulesTotalAmount);
    //     return _vestedTokenPool.sub(vestingSchedulesTotalAmount);
    // }

    /**

    * @dev Computes the next vesting schedule identifier for a given holder address.

    */
    function computeNextVestingScheduleIdForHolder(address holder)
        public
        view
        returns(bytes32){
        return computeVestingScheduleIdForAddressAndIndex(holder, holdersVestingCount[holder]);
    }

    /**

    * @dev Returns the last vesting schedule for a given holder address.

    */
    function getLastVestingScheduleForHolder(address holder)
        public
        view
        returns(VestingSchedule memory){
        return vestingSchedules[computeVestingScheduleIdForAddressAndIndex(holder, holdersVestingCount[holder] - 1)];
    }

    /**

    * @dev Computes the vesting schedule identifier for an address and an index.

    */
    function computeVestingScheduleIdForAddressAndIndex(address holder, uint256 index)
        public
        pure
        returns(bytes32){
        return keccak256(abi.encodePacked(holder, index));
    }

    /**

    * @dev Computes the releasable amount of tokens for a vesting schedule.

    * @return the amount of releasable tokens

    */
    function _computeReleasableAmount(VestingSchedule memory vestingSchedule)
    internal
    view
    returns(uint256){
        uint256 currentTime = getCurrentTime();
        if ((currentTime < vestingSchedule.cliff) || vestingSchedule.revoked == true) {
            return 0;
        } else if (currentTime >= vestingSchedule.start.add(vestingSchedule.duration)) {
            return vestingSchedule.amountTotal.sub(vestingSchedule.released);
        } else {
            uint256 timeFromStart = currentTime.sub(vestingSchedule.start);
            uint secondsPerSlice = vestingSchedule.slicePeriodSeconds;
            uint256 vestedSlicePeriods = timeFromStart.div(secondsPerSlice);
            uint256 vestedSeconds = vestedSlicePeriods.mul(secondsPerSlice);
            uint256 vestedAmount = vestingSchedule.amountTotal.mul(vestedSeconds).div(vestingSchedule.duration);
            vestedAmount = vestedAmount.sub(vestingSchedule.released);
            return vestedAmount;
        }
    }

    function _computeLockedAmount(VestingSchedule memory vestingSchedule)
    internal
    view
    returns(uint256){
        uint256 currentTime = getCurrentTime();
        if (vestingSchedule.revoked == true) {
            return 0;
        } else if ((currentTime < vestingSchedule.cliff)) {
            return vestingSchedule.amountTotal;
        } else if (currentTime >= vestingSchedule.start.add(vestingSchedule.duration)) {
            return 0;
        } else {
            uint256 timeFromStart = currentTime.sub(vestingSchedule.start);
            uint secondsPerSlice = vestingSchedule.slicePeriodSeconds;
            uint256 vestedSlicePeriods = timeFromStart.div(secondsPerSlice);
            uint256 vestedSeconds = vestedSlicePeriods.mul(secondsPerSlice);
            uint256 vestedAmount = vestingSchedule.amountTotal.mul(vestedSeconds).div(vestingSchedule.duration);
            return vestingSchedule.amountTotal.sub(vestedAmount);
        }
    }

    function getCurrentTime()
        internal
        virtual
        view
        returns(uint256){
        return block.timestamp;
    }

    function _beforeTokenTransfer(address operator, address from, address to, uint256 amount) internal override virtual {
        uint totalLocked = computeLockedAmount(from);
        
        if (from != address(0)) require(amount <= balanceOf(from).sub(totalLocked), 'check vesting or balance');
        super._beforeTokenTransfer(operator, from, to, amount);
    }

    // function createVestingSchedule(
    //     address _beneficiary,
    //     uint256 _start,
    //     uint256 _cliff,
    //     uint256 _duration,
    //     uint256 _slicePeriodSeconds,
    //     bool _revocable,
    //     uint256 _amount
    // )
    function vestedTransfer(

        address _recipient, 

        uint256 _amount, 

        uint256 _start, 

        uint256 _cliff, 

        uint256 _duration, 

        uint256 _slicePeriodSeconds, 

        bool _revocable

    ) public virtual {
        require(hasRole(MANAGER_ROLE, _msgSender()), "unauthorized");
        createVestingSchedule(_recipient, _start, _cliff, _duration, _slicePeriodSeconds, _revocable, _amount);
        super.transfer(_recipient, _amount);
    }

    function vestedBatchTransfer(

        address[] calldata _recipients, 

        uint256[] calldata _amounts, 

        uint256 _start, 

        uint256 _cliff, 

        uint256 _duration, 

        uint256 _slicePeriodSeconds, 

        bool _revocable

    ) public virtual {
        require(hasRole(MANAGER_ROLE, _msgSender()), "unauthorized");
        require(_recipients.length == _amounts.length, "address & amount size mismatch");
        require(_duration > 0, "duration must be > 0");
        require(_cliff <= _duration, "invalid cliff");
        require(_slicePeriodSeconds >= 1, "slicePeriodSeconds must be >= 1");
        uint256 cliff = _start.add(_cliff);

        for (uint i; i < _recipients.length; i++) {
            require(_amounts[i] > 0, "amount must be > 0");
            bytes32 vestingScheduleId = this.computeNextVestingScheduleIdForHolder(_recipients[i]);
            vestingSchedules[vestingScheduleId] = VestingSchedule(

                true,

                _recipients[i],

                cliff,

                _start,

                _duration,

                _slicePeriodSeconds,

                _revocable,

                _amounts[i],

                0,

                false

            );
            vestingSchedulesTotalAmount = vestingSchedulesTotalAmount.add(_amounts[i]);
            vestingSchedulesIds.push(vestingScheduleId);
            uint256 currentVestingCount = holdersVestingCount[_recipients[i]];
            holdersVestingCount[_recipients[i]] = currentVestingCount.add(1);

            // todo: add event emit
            emit VestingCreated(vestingScheduleId, _recipients[i], _amounts[i]);
            super.transfer(_recipients[i], _amounts[i]);
        }
    }

    function _authorizeUpgrade(address newImplementation)
        internal
        override
        onlyOwner
    {
        require(!_upgradeLocked, "further upgrade not possible now");
    }
}