Cryo Explorer Ethereum Mainnet

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (interfaces/IERC1271.sol)

pragma solidity ^0.8.20;

/**
 * @dev Interface of the ERC1271 standard signature validation method for
 * contracts as defined in https://eips.ethereum.org/EIPS/eip-1271[ERC-1271].
 */
interface IERC1271 {
    /**
     * @dev Should return whether the signature provided is valid for the provided data
     * @param hash      Hash of the data to be signed
     * @param signature Signature byte array associated with _data
     */
    function isValidSignature(bytes32 hash, bytes memory signature) external view returns (bytes4 magicValue);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (interfaces/IERC5267.sol)

pragma solidity ^0.8.20;

interface IERC5267 {
    /**
     * @dev MAY be emitted to signal that the domain could have changed.
     */
    event EIP712DomainChanged();

    /**
     * @dev returns the fields and values that describe the domain separator used by this contract for EIP-712
     * signature.
     */
    function eip712Domain()
        external
        view
        returns (
            bytes1 fields,
            string memory name,
            string memory version,
            uint256 chainId,
            address verifyingContract,
            bytes32 salt,
            uint256[] memory extensions
        );
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.20;

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

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

    /**
     * @dev Moves a `value` amount of 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 value) 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 a `value` amount of tokens 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 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` 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 value) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.20;

/**
 * @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.
 *
 * ==== Security Considerations
 *
 * There are two important considerations concerning the use of `permit`. The first is that a valid permit signature
 * expresses an allowance, and it should not be assumed to convey additional meaning. In particular, it should not be
 * considered as an intention to spend the allowance in any specific way. The second is that because permits have
 * built-in replay protection and can be submitted by anyone, they can be frontrun. A protocol that uses permits should
 * take this into consideration and allow a `permit` call to fail. Combining these two aspects, a pattern that may be
 * generally recommended is:
 *
 * ```solidity
 * function doThingWithPermit(..., uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s) public {
 *     try token.permit(msg.sender, address(this), value, deadline, v, r, s) {} catch {}
 *     doThing(..., value);
 * }
 *
 * function doThing(..., uint256 value) public {
 *     token.safeTransferFrom(msg.sender, address(this), value);
 *     ...
 * }
 * ```
 *
 * Observe that: 1) `msg.sender` is used as the owner, leaving no ambiguity as to the signer intent, and 2) the use of
 * `try/catch` allows the permit to fail and makes the code tolerant to frontrunning. (See also
 * {SafeERC20-safeTransferFrom}).
 *
 * Additionally, note that smart contract wallets (such as Argent or Safe) are not able to produce permit signatures, so
 * contracts should have entry points that don't rely on permit.
 */
interface IERC20Permit {
    /**
     * @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].
     *
     * CAUTION: See Security Considerations above.
     */
    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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "../IERC20.sol";
import {IERC20Permit} from "../extensions/IERC20Permit.sol";
import {Address} from "../../../utils/Address.sol";

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

    /**
     * @dev An operation with an ERC20 token failed.
     */
    error SafeERC20FailedOperation(address token);

    /**
     * @dev Indicates a failed `decreaseAllowance` request.
     */
    error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transfer, (to, value)));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transferFrom, (from, to, value)));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        forceApprove(token, spender, oldAllowance + value);
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `requestedDecrease`. If `token` returns no
     * value, non-reverting calls are assumed to be successful.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal {
        unchecked {
            uint256 currentAllowance = token.allowance(address(this), spender);
            if (currentAllowance < requestedDecrease) {
                revert SafeERC20FailedDecreaseAllowance(spender, currentAllowance, requestedDecrease);
            }
            forceApprove(token, spender, currentAllowance - requestedDecrease);
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
     * to be set to zero before setting it to a non-zero value, such as USDT.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeCall(token.approve, (spender, value));

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeCall(token.approve, (spender, 0)));
            _callOptionalReturn(token, approvalCall);
        }
    }

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

        bytes memory returndata = address(token).functionCall(data);
        if (returndata.length != 0 && !abi.decode(returndata, (bool))) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @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).
     *
     * This is a variant of {_callOptionalReturn} that silents catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        // 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 cannot use {Address-functionCall} here since this should return false
        // and not revert is the subcall reverts.

        (bool success, bytes memory returndata) = address(token).call(data);
        return success && (returndata.length == 0 || abi.decode(returndata, (bool))) && address(token).code.length > 0;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Address.sol)

pragma solidity ^0.8.20;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev The ETH balance of the account is not enough to perform the operation.
     */
    error AddressInsufficientBalance(address account);

    /**
     * @dev There's no code at `target` (it is not a contract).
     */
    error AddressEmptyCode(address target);

    /**
     * @dev A call to an address target failed. The target may have reverted.
     */
    error FailedInnerCall();

    /**
     * @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://consensys.net/diligence/blog/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/v0.8.20/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        if (address(this).balance < amount) {
            revert AddressInsufficientBalance(address(this));
        }

        (bool success, ) = recipient.call{value: amount}("");
        if (!success) {
            revert FailedInnerCall();
        }
    }

    /**
     * @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 or custom error, it is bubbled
     * up by this function (like regular Solidity function calls). However, if
     * the call reverted with no returned reason, this function reverts with a
     * {FailedInnerCall} error.
     *
     * 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.
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0);
    }

    /**
     * @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`.
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        if (address(this).balance < value) {
            revert AddressInsufficientBalance(address(this));
        }
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and reverts if the target
     * was not a contract or bubbling up the revert reason (falling back to {FailedInnerCall}) in case of an
     * unsuccessful call.
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata
    ) internal view returns (bytes memory) {
        if (!success) {
            _revert(returndata);
        } else {
            // only check if target is a contract if the call was successful and the return data is empty
            // otherwise we already know that it was a contract
            if (returndata.length == 0 && target.code.length == 0) {
                revert AddressEmptyCode(target);
            }
            return returndata;
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and reverts if it wasn't, either by bubbling the
     * revert reason or with a default {FailedInnerCall} error.
     */
    function verifyCallResult(bool success, bytes memory returndata) internal pure returns (bytes memory) {
        if (!success) {
            _revert(returndata);
        } else {
            return returndata;
        }
    }

    /**
     * @dev Reverts with returndata if present. Otherwise reverts with {FailedInnerCall}.
     */
    function _revert(bytes memory returndata) 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 FailedInnerCall();
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Multicall.sol)

pragma solidity ^0.8.20;

import {Address} from "./Address.sol";

/**
 * @dev Provides a function to batch together multiple calls in a single external call.
 */
abstract contract Multicall {
    /**
     * @dev Receives and executes a batch of function calls on this contract.
     * @custom:oz-upgrades-unsafe-allow-reachable delegatecall
     */
    function multicall(bytes[] calldata data) external virtual returns (bytes[] memory results) {
        results = new bytes[](data.length);
        for (uint256 i = 0; i < data.length; i++) {
            results[i] = Address.functionDelegateCall(address(this), data[i]);
        }
        return results;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Nonces.sol)
pragma solidity ^0.8.20;

/**
 * @dev Provides tracking nonces for addresses. Nonces will only increment.
 */
abstract contract Nonces {
    /**
     * @dev The nonce used for an `account` is not the expected current nonce.
     */
    error InvalidAccountNonce(address account, uint256 currentNonce);

    mapping(address account => uint256) private _nonces;

    /**
     * @dev Returns the next unused nonce for an address.
     */
    function nonces(address owner) public view virtual returns (uint256) {
        return _nonces[owner];
    }

    /**
     * @dev Consumes a nonce.
     *
     * Returns the current value and increments nonce.
     */
    function _useNonce(address owner) internal virtual returns (uint256) {
        // For each account, the nonce has an initial value of 0, can only be incremented by one, and cannot be
        // decremented or reset. This guarantees that the nonce never overflows.
        unchecked {
            // It is important to do x++ and not ++x here.
            return _nonces[owner]++;
        }
    }

    /**
     * @dev Same as {_useNonce} but checking that `nonce` is the next valid for `owner`.
     */
    function _useCheckedNonce(address owner, uint256 nonce) internal virtual {
        uint256 current = _useNonce(owner);
        if (nonce != current) {
            revert InvalidAccountNonce(owner, current);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/ShortStrings.sol)

pragma solidity ^0.8.20;

import {StorageSlot} from "./StorageSlot.sol";

// | string  | 0xAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA   |
// | length  | 0x                                                              BB |
type ShortString is bytes32;

/**
 * @dev This library provides functions to convert short memory strings
 * into a `ShortString` type that can be used as an immutable variable.
 *
 * Strings of arbitrary length can be optimized using this library if
 * they are short enough (up to 31 bytes) by packing them with their
 * length (1 byte) in a single EVM word (32 bytes). Additionally, a
 * fallback mechanism can be used for every other case.
 *
 * Usage example:
 *
 * ```solidity
 * contract Named {
 *     using ShortStrings for *;
 *
 *     ShortString private immutable _name;
 *     string private _nameFallback;
 *
 *     constructor(string memory contractName) {
 *         _name = contractName.toShortStringWithFallback(_nameFallback);
 *     }
 *
 *     function name() external view returns (string memory) {
 *         return _name.toStringWithFallback(_nameFallback);
 *     }
 * }
 * ```
 */
library ShortStrings {
    // Used as an identifier for strings longer than 31 bytes.
    bytes32 private constant FALLBACK_SENTINEL = 0x00000000000000000000000000000000000000000000000000000000000000FF;

    error StringTooLong(string str);
    error InvalidShortString();

    /**
     * @dev Encode a string of at most 31 chars into a `ShortString`.
     *
     * This will trigger a `StringTooLong` error is the input string is too long.
     */
    function toShortString(string memory str) internal pure returns (ShortString) {
        bytes memory bstr = bytes(str);
        if (bstr.length > 31) {
            revert StringTooLong(str);
        }
        return ShortString.wrap(bytes32(uint256(bytes32(bstr)) | bstr.length));
    }

    /**
     * @dev Decode a `ShortString` back to a "normal" string.
     */
    function toString(ShortString sstr) internal pure returns (string memory) {
        uint256 len = byteLength(sstr);
        // using `new string(len)` would work locally but is not memory safe.
        string memory str = new string(32);
        /// @solidity memory-safe-assembly
        assembly {
            mstore(str, len)
            mstore(add(str, 0x20), sstr)
        }
        return str;
    }

    /**
     * @dev Return the length of a `ShortString`.
     */
    function byteLength(ShortString sstr) internal pure returns (uint256) {
        uint256 result = uint256(ShortString.unwrap(sstr)) & 0xFF;
        if (result > 31) {
            revert InvalidShortString();
        }
        return result;
    }

    /**
     * @dev Encode a string into a `ShortString`, or write it to storage if it is too long.
     */
    function toShortStringWithFallback(string memory value, string storage store) internal returns (ShortString) {
        if (bytes(value).length < 32) {
            return toShortString(value);
        } else {
            StorageSlot.getStringSlot(store).value = value;
            return ShortString.wrap(FALLBACK_SENTINEL);
        }
    }

    /**
     * @dev Decode a string that was encoded to `ShortString` or written to storage using {setWithFallback}.
     */
    function toStringWithFallback(ShortString value, string storage store) internal pure returns (string memory) {
        if (ShortString.unwrap(value) != FALLBACK_SENTINEL) {
            return toString(value);
        } else {
            return store;
        }
    }

    /**
     * @dev Return the length of a string that was encoded to `ShortString` or written to storage using
     * {setWithFallback}.
     *
     * WARNING: This will return the "byte length" of the string. This may not reflect the actual length in terms of
     * actual characters as the UTF-8 encoding of a single character can span over multiple bytes.
     */
    function byteLengthWithFallback(ShortString value, string storage store) internal view returns (uint256) {
        if (ShortString.unwrap(value) != FALLBACK_SENTINEL) {
            return byteLength(value);
        } else {
            return bytes(store).length;
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/StorageSlot.sol)
// This file was procedurally generated from scripts/generate/templates/StorageSlot.js.

pragma solidity ^0.8.20;

/**
 * @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:
 * ```solidity
 * 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(newImplementation.code.length > 0);
 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
 *     }
 * }
 * ```
 */
library StorageSlot {
    struct AddressSlot {
        address value;
    }

    struct BooleanSlot {
        bool value;
    }

    struct Bytes32Slot {
        bytes32 value;
    }

    struct Uint256Slot {
        uint256 value;
    }

    struct StringSlot {
        string value;
    }

    struct BytesSlot {
        bytes 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
        }
    }

    /**
     * @dev Returns an `StringSlot` with member `value` located at `slot`.
     */
    function getStringSlot(bytes32 slot) internal pure returns (StringSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `StringSlot` representation of the string storage pointer `store`.
     */
    function getStringSlot(string storage store) internal pure returns (StringSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := store.slot
        }
    }

    /**
     * @dev Returns an `BytesSlot` with member `value` located at `slot`.
     */
    function getBytesSlot(bytes32 slot) internal pure returns (BytesSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `BytesSlot` representation of the bytes storage pointer `store`.
     */
    function getBytesSlot(bytes storage store) internal pure returns (BytesSlot storage r) {
        /// @solidity memory-safe-assembly
        assembly {
            r.slot := store.slot
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/Strings.sol)

pragma solidity ^0.8.20;

import {Math} from "./math/Math.sol";
import {SignedMath} from "./math/SignedMath.sol";

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant HEX_DIGITS = "0123456789abcdef";
    uint8 private constant ADDRESS_LENGTH = 20;

    /**
     * @dev The `value` string doesn't fit in the specified `length`.
     */
    error StringsInsufficientHexLength(uint256 value, uint256 length);

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.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), HEX_DIGITS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `int256` to its ASCII `string` decimal representation.
     */
    function toStringSigned(int256 value) internal pure returns (string memory) {
        return string.concat(value < 0 ? "-" : "", toString(SignedMath.abs(value)));
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, Math.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) {
        uint256 localValue = value;
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = HEX_DIGITS[localValue & 0xf];
            localValue >>= 4;
        }
        if (localValue != 0) {
            revert StringsInsufficientHexLength(value, length);
        }
        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);
    }

    /**
     * @dev Returns true if the two strings are equal.
     */
    function equal(string memory a, string memory b) internal pure returns (bool) {
        return bytes(a).length == bytes(b).length && keccak256(bytes(a)) == keccak256(bytes(b));
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/ECDSA.sol)

pragma solidity ^0.8.20;

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS
    }

    /**
     * @dev The signature derives the `address(0)`.
     */
    error ECDSAInvalidSignature();

    /**
     * @dev The signature has an invalid length.
     */
    error ECDSAInvalidSignatureLength(uint256 length);

    /**
     * @dev The signature has an S value that is in the upper half order.
     */
    error ECDSAInvalidSignatureS(bytes32 s);

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with `signature` or an error. This will not
     * return address(0) without also returning an error description. Errors are documented using an enum (error type)
     * and a bytes32 providing additional information about the error.
     *
     * If no error is returned, then the address can be used for verification purposes.
     *
     * The `ecrecover` EVM precompile allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {MessageHashUtils-toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError, bytes32) {
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            /// @solidity memory-safe-assembly
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength, bytes32(signature.length));
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM precompile allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {MessageHashUtils-toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error, bytes32 errorArg) = tryRecover(hash, signature);
        _throwError(error, errorArg);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     */
    function tryRecover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address, RecoverError, bytes32) {
        unchecked {
            bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
            // We do not check for an overflow here since the shift operation results in 0 or 1.
            uint8 v = uint8((uint256(vs) >> 255) + 27);
            return tryRecover(hash, v, r, s);
        }
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     */
    function recover(bytes32 hash, bytes32 r, bytes32 vs) internal pure returns (address) {
        (address recovered, RecoverError error, bytes32 errorArg) = tryRecover(hash, r, vs);
        _throwError(error, errorArg);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError, bytes32) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS, s);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature, bytes32(0));
        }

        return (signer, RecoverError.NoError, bytes32(0));
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(bytes32 hash, uint8 v, bytes32 r, bytes32 s) internal pure returns (address) {
        (address recovered, RecoverError error, bytes32 errorArg) = tryRecover(hash, v, r, s);
        _throwError(error, errorArg);
        return recovered;
    }

    /**
     * @dev Optionally reverts with the corresponding custom error according to the `error` argument provided.
     */
    function _throwError(RecoverError error, bytes32 errorArg) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert ECDSAInvalidSignature();
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert ECDSAInvalidSignatureLength(uint256(errorArg));
        } else if (error == RecoverError.InvalidSignatureS) {
            revert ECDSAInvalidSignatureS(errorArg);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/EIP712.sol)

pragma solidity ^0.8.20;

import {MessageHashUtils} from "./MessageHashUtils.sol";
import {ShortStrings, ShortString} from "../ShortStrings.sol";
import {IERC5267} from "../../interfaces/IERC5267.sol";

/**
 * @dev https://eips.ethereum.org/EIPS/eip-712[EIP 712] is a standard for hashing and signing of typed structured data.
 *
 * The encoding scheme specified in the EIP requires a domain separator and a hash of the typed structured data, whose
 * encoding is very generic and therefore its implementation in Solidity is not feasible, thus this contract
 * does not implement the encoding itself. Protocols need to implement the type-specific encoding they need in order to
 * produce the hash of their typed data using a combination of `abi.encode` and `keccak256`.
 *
 * This contract implements the EIP 712 domain separator ({_domainSeparatorV4}) that is used as part of the encoding
 * scheme, and the final step of the encoding to obtain the message digest that is then signed via ECDSA
 * ({_hashTypedDataV4}).
 *
 * The implementation of the domain separator was designed to be as efficient as possible while still properly updating
 * the chain id to protect against replay attacks on an eventual fork of the chain.
 *
 * NOTE: This contract implements the version of the encoding known as "v4", as implemented by the JSON RPC method
 * https://docs.metamask.io/guide/signing-data.html[`eth_signTypedDataV4` in MetaMask].
 *
 * NOTE: In the upgradeable version of this contract, the cached values will correspond to the address, and the domain
 * separator of the implementation contract. This will cause the {_domainSeparatorV4} function to always rebuild the
 * separator from the immutable values, which is cheaper than accessing a cached version in cold storage.
 *
 * @custom:oz-upgrades-unsafe-allow state-variable-immutable
 */
abstract contract EIP712 is IERC5267 {
    using ShortStrings for *;

    bytes32 private constant TYPE_HASH =
        keccak256("EIP712Domain(string name,string version,uint256 chainId,address verifyingContract)");

    // Cache the domain separator as an immutable value, but also store the chain id that it corresponds to, in order to
    // invalidate the cached domain separator if the chain id changes.
    bytes32 private immutable _cachedDomainSeparator;
    uint256 private immutable _cachedChainId;
    address private immutable _cachedThis;

    bytes32 private immutable _hashedName;
    bytes32 private immutable _hashedVersion;

    ShortString private immutable _name;
    ShortString private immutable _version;
    string private _nameFallback;
    string private _versionFallback;

    /**
     * @dev Initializes the domain separator and parameter caches.
     *
     * The meaning of `name` and `version` is specified in
     * https://eips.ethereum.org/EIPS/eip-712#definition-of-domainseparator[EIP 712]:
     *
     * - `name`: the user readable name of the signing domain, i.e. the name of the DApp or the protocol.
     * - `version`: the current major version of the signing domain.
     *
     * NOTE: These parameters cannot be changed except through a xref:learn::upgrading-smart-contracts.adoc[smart
     * contract upgrade].
     */
    constructor(string memory name, string memory version) {
        _name = name.toShortStringWithFallback(_nameFallback);
        _version = version.toShortStringWithFallback(_versionFallback);
        _hashedName = keccak256(bytes(name));
        _hashedVersion = keccak256(bytes(version));

        _cachedChainId = block.chainid;
        _cachedDomainSeparator = _buildDomainSeparator();
        _cachedThis = address(this);
    }

    /**
     * @dev Returns the domain separator for the current chain.
     */
    function _domainSeparatorV4() internal view returns (bytes32) {
        if (address(this) == _cachedThis && block.chainid == _cachedChainId) {
            return _cachedDomainSeparator;
        } else {
            return _buildDomainSeparator();
        }
    }

    function _buildDomainSeparator() private view returns (bytes32) {
        return keccak256(abi.encode(TYPE_HASH, _hashedName, _hashedVersion, block.chainid, address(this)));
    }

    /**
     * @dev Given an already https://eips.ethereum.org/EIPS/eip-712#definition-of-hashstruct[hashed struct], this
     * function returns the hash of the fully encoded EIP712 message for this domain.
     *
     * This hash can be used together with {ECDSA-recover} to obtain the signer of a message. For example:
     *
     * ```solidity
     * bytes32 digest = _hashTypedDataV4(keccak256(abi.encode(
     *     keccak256("Mail(address to,string contents)"),
     *     mailTo,
     *     keccak256(bytes(mailContents))
     * )));
     * address signer = ECDSA.recover(digest, signature);
     * ```
     */
    function _hashTypedDataV4(bytes32 structHash) internal view virtual returns (bytes32) {
        return MessageHashUtils.toTypedDataHash(_domainSeparatorV4(), structHash);
    }

    /**
     * @dev See {IERC-5267}.
     */
    function eip712Domain()
        public
        view
        virtual
        returns (
            bytes1 fields,
            string memory name,
            string memory version,
            uint256 chainId,
            address verifyingContract,
            bytes32 salt,
            uint256[] memory extensions
        )
    {
        return (
            hex"0f", // 01111
            _EIP712Name(),
            _EIP712Version(),
            block.chainid,
            address(this),
            bytes32(0),
            new uint256[](0)
        );
    }

    /**
     * @dev The name parameter for the EIP712 domain.
     *
     * NOTE: By default this function reads _name which is an immutable value.
     * It only reads from storage if necessary (in case the value is too large to fit in a ShortString).
     */
    // solhint-disable-next-line func-name-mixedcase
    function _EIP712Name() internal view returns (string memory) {
        return _name.toStringWithFallback(_nameFallback);
    }

    /**
     * @dev The version parameter for the EIP712 domain.
     *
     * NOTE: By default this function reads _version which is an immutable value.
     * It only reads from storage if necessary (in case the value is too large to fit in a ShortString).
     */
    // solhint-disable-next-line func-name-mixedcase
    function _EIP712Version() internal view returns (string memory) {
        return _version.toStringWithFallback(_versionFallback);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/MessageHashUtils.sol)

pragma solidity ^0.8.20;

import {Strings} from "../Strings.sol";

/**
 * @dev Signature message hash utilities for producing digests to be consumed by {ECDSA} recovery or signing.
 *
 * The library provides methods for generating a hash of a message that conforms to the
 * https://eips.ethereum.org/EIPS/eip-191[EIP 191] and https://eips.ethereum.org/EIPS/eip-712[EIP 712]
 * specifications.
 */
library MessageHashUtils {
    /**
     * @dev Returns the keccak256 digest of an EIP-191 signed data with version
     * `0x45` (`personal_sign` messages).
     *
     * The digest is calculated by prefixing a bytes32 `messageHash` with
     * `"\x19Ethereum Signed Message:\n32"` and hashing the result. It corresponds with the
     * hash signed when using the https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`] JSON-RPC method.
     *
     * NOTE: The `messageHash` parameter is intended to be the result of hashing a raw message with
     * keccak256, although any bytes32 value can be safely used because the final digest will
     * be re-hashed.
     *
     * See {ECDSA-recover}.
     */
    function toEthSignedMessageHash(bytes32 messageHash) internal pure returns (bytes32 digest) {
        /// @solidity memory-safe-assembly
        assembly {
            mstore(0x00, "\x19Ethereum Signed Message:\n32") // 32 is the bytes-length of messageHash
            mstore(0x1c, messageHash) // 0x1c (28) is the length of the prefix
            digest := keccak256(0x00, 0x3c) // 0x3c is the length of the prefix (0x1c) + messageHash (0x20)
        }
    }

    /**
     * @dev Returns the keccak256 digest of an EIP-191 signed data with version
     * `0x45` (`personal_sign` messages).
     *
     * The digest is calculated by prefixing an arbitrary `message` with
     * `"\x19Ethereum Signed Message:\n" + len(message)` and hashing the result. It corresponds with the
     * hash signed when using the https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`] JSON-RPC method.
     *
     * See {ECDSA-recover}.
     */
    function toEthSignedMessageHash(bytes memory message) internal pure returns (bytes32) {
        return
            keccak256(bytes.concat("\x19Ethereum Signed Message:\n", bytes(Strings.toString(message.length)), message));
    }

    /**
     * @dev Returns the keccak256 digest of an EIP-191 signed data with version
     * `0x00` (data with intended validator).
     *
     * The digest is calculated by prefixing an arbitrary `data` with `"\x19\x00"` and the intended
     * `validator` address. Then hashing the result.
     *
     * See {ECDSA-recover}.
     */
    function toDataWithIntendedValidatorHash(address validator, bytes memory data) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked(hex"19_00", validator, data));
    }

    /**
     * @dev Returns the keccak256 digest of an EIP-712 typed data (EIP-191 version `0x01`).
     *
     * The digest is calculated from a `domainSeparator` and a `structHash`, by prefixing them with
     * `\x19\x01` and hashing the result. It corresponds to the hash signed by the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`] JSON-RPC method as part of EIP-712.
     *
     * See {ECDSA-recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32 digest) {
        /// @solidity memory-safe-assembly
        assembly {
            let ptr := mload(0x40)
            mstore(ptr, hex"19_01")
            mstore(add(ptr, 0x02), domainSeparator)
            mstore(add(ptr, 0x22), structHash)
            digest := keccak256(ptr, 0x42)
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/cryptography/SignatureChecker.sol)

pragma solidity ^0.8.20;

import {ECDSA} from "./ECDSA.sol";
import {IERC1271} from "../../interfaces/IERC1271.sol";

/**
 * @dev Signature verification helper that can be used instead of `ECDSA.recover` to seamlessly support both ECDSA
 * signatures from externally owned accounts (EOAs) as well as ERC1271 signatures from smart contract wallets like
 * Argent and Safe Wallet (previously Gnosis Safe).
 */
library SignatureChecker {
    /**
     * @dev Checks if a signature is valid for a given signer and data hash. If the signer is a smart contract, the
     * signature is validated against that smart contract using ERC1271, otherwise it's validated using `ECDSA.recover`.
     *
     * NOTE: Unlike ECDSA signatures, contract signatures are revocable, and the outcome of this function can thus
     * change through time. It could return true at block N and false at block N+1 (or the opposite).
     */
    function isValidSignatureNow(address signer, bytes32 hash, bytes memory signature) internal view returns (bool) {
        (address recovered, ECDSA.RecoverError error, ) = ECDSA.tryRecover(hash, signature);
        return
            (error == ECDSA.RecoverError.NoError && recovered == signer) ||
            isValidERC1271SignatureNow(signer, hash, signature);
    }

    /**
     * @dev Checks if a signature is valid for a given signer and data hash. The signature is validated
     * against the signer smart contract using ERC1271.
     *
     * NOTE: Unlike ECDSA signatures, contract signatures are revocable, and the outcome of this function can thus
     * change through time. It could return true at block N and false at block N+1 (or the opposite).
     */
    function isValidERC1271SignatureNow(
        address signer,
        bytes32 hash,
        bytes memory signature
    ) internal view returns (bool) {
        (bool success, bytes memory result) = signer.staticcall(
            abi.encodeCall(IERC1271.isValidSignature, (hash, signature))
        );
        return (success &&
            result.length >= 32 &&
            abi.decode(result, (bytes32)) == bytes32(IERC1271.isValidSignature.selector));
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/Math.sol)

pragma solidity ^0.8.20;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Muldiv operation overflow.
     */
    error MathOverflowedMulDiv();

    enum Rounding {
        Floor, // Toward negative infinity
        Ceil, // Toward positive infinity
        Trunc, // Toward zero
        Expand // Away from zero
    }

    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     */
    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.
     */
    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.
     */
    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.
     */
    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.
     */
    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 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 towards infinity instead
     * of rounding towards zero.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        if (b == 0) {
            // Guarantee the same behavior as in a regular Solidity division.
            return a / b;
        }

        // (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 = x * y; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            if (denominator <= prod1) {
                revert MathOverflowedMulDiv();
            }

            ///////////////////////////////////////////////
            // 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.

            uint256 twos = denominator & (0 - denominator);
            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 (unsignedRoundsUp(rounding) && 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
     * towards zero.
     *
     * 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 + (unsignedRoundsUp(rounding) && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2 of a positive value rounded towards zero.
     * 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 + (unsignedRoundsUp(rounding) && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10 of a positive value rounded towards zero.
     * 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 + (unsignedRoundsUp(rounding) && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256 of a positive value rounded towards zero.
     * 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 256, 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 + (unsignedRoundsUp(rounding) && 1 << (result << 3) < value ? 1 : 0);
        }
    }

    /**
     * @dev Returns whether a provided rounding mode is considered rounding up for unsigned integers.
     */
    function unsignedRoundsUp(Rounding rounding) internal pure returns (bool) {
        return uint8(rounding) % 2 == 1;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (utils/math/SignedMath.sol)

pragma solidity ^0.8.20;

/**
 * @dev Standard signed math utilities missing in the Solidity language.
 */
library SignedMath {
    /**
     * @dev Returns the largest of two signed numbers.
     */
    function max(int256 a, int256 b) internal pure returns (int256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two signed numbers.
     */
    function min(int256 a, int256 b) internal pure returns (int256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two signed numbers without overflow.
     * The result is rounded towards zero.
     */
    function average(int256 a, int256 b) internal pure returns (int256) {
        // Formula from the book "Hacker's Delight"
        int256 x = (a & b) + ((a ^ b) >> 1);
        return x + (int256(uint256(x) >> 255) & (a ^ b));
    }

    /**
     * @dev Returns the absolute unsigned value of a signed value.
     */
    function abs(int256 n) internal pure returns (uint256) {
        unchecked {
            // must be unchecked in order to support `n = type(int256).min`
            return uint256(n >= 0 ? n : -n);
        }
    }
}

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity 0.8.23;

import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";

/// @title DelegationSurrogate
/// @author ScopeLift
/// @notice A dead-simple contract whose only purpose is to hold governance tokens on behalf of
/// users while delegating voting power to one specific delegatee. This is needed because a single
/// address can only delegate its (full) token weight to a single address at a time. Thus, when a
/// contract holds governance tokens in a pool on behalf of disparate token holders, those holders
/// are typically disenfranchised from their governance rights.
///
/// If a pool contract deploys a DelegationSurrogate for each delegatee, and transfers each
/// depositor's tokens to the appropriate  surrogate—or deploys it on their behalf—users can retain
/// their governance rights.
///
/// The pool contract deploying the surrogates must handle all accounting. The surrogate simply
/// delegates its voting weight and max-approves its deployer to allow tokens to be reclaimed.
contract DelegationSurrogate {
  /// @param _token The governance token that will be held by this surrogate
  /// @param _delegatee The address of the would-be voter to which this surrogate will delegate its
  /// voting weight. 100% of all voting tokens held by this surrogate will be delegated to this
  /// address.
  constructor(IERC20Delegates _token, address _delegatee) {
    _token.delegate(_delegatee);
    _token.approve(msg.sender, type(uint256).max);
  }
}

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity 0.8.23;

import {DelegationSurrogate} from "src/DelegationSurrogate.sol";
import {INotifiableRewardReceiver} from "src/interfaces/INotifiableRewardReceiver.sol";
import {IERC20Delegates} from "src/interfaces/IERC20Delegates.sol";
import {IERC20} from "openzeppelin/token/ERC20/IERC20.sol";
import {SafeERC20} from "openzeppelin/token/ERC20/utils/SafeERC20.sol";
import {Multicall} from "openzeppelin/utils/Multicall.sol";
import {Nonces} from "openzeppelin/utils/Nonces.sol";
import {SignatureChecker} from "openzeppelin/utils/cryptography/SignatureChecker.sol";
import {EIP712} from "openzeppelin/utils/cryptography/EIP712.sol";

/// @title TermStaker (adopted from UniStaker)
/// @author adopted by Term Labs from ScopeLift
/// @notice This contract manages the distribution of rewards to stakers. Rewards are denominated
/// in an ERC20 token and sent to the contract by authorized reward notifiers. To stake means to
/// deposit a designated, delegable ERC20 governance token and leave it over a period of time.
/// The contract allows stakers to delegate the voting power of the tokens they stake to any
/// governance delegatee on a per deposit basis. The contract also allows stakers to designate the
/// beneficiary address that earns rewards for the associated deposit.
///
/// The staking mechanism of this contract is directly inspired by the Synthetix StakingRewards.sol
/// implementation. The core mechanic involves the streaming of rewards over a designated period
/// of time. Each staker earns rewards proportional to their share of the total stake, and each
/// staker earns only while their tokens are staked. Stakers may add or withdraw their stake at any
/// point. Beneficiaries can claim the rewards they've earned at any point. When a new reward is
/// received, the reward duration restarts, and the rate at which rewards are streamed is updated
/// to include the newly received rewards along with any remaining rewards that have finished
/// streaming since the last time a reward was received.
contract TermStaker is INotifiableRewardReceiver, Multicall, EIP712, Nonces {
  type DepositIdentifier is uint256;

  /// @notice Emitted when stake is deposited by a depositor, either to a new deposit or one that
  /// already exists.
  event StakeDeposited(
    address owner, DepositIdentifier indexed depositId, uint256 amount, uint256 depositBalance
  );

  /// @notice Emitted when a depositor withdraws some portion of stake from a given deposit.
  event StakeWithdrawn(DepositIdentifier indexed depositId, uint256 amount, uint256 depositBalance);

  /// @notice Emitted when a deposit's delegatee is changed.
  event DelegateeAltered(
    DepositIdentifier indexed depositId, address oldDelegatee, address newDelegatee
  );

  /// @notice Emitted when a deposit's beneficiary is changed.
  event BeneficiaryAltered(
    DepositIdentifier indexed depositId,
    address indexed oldBeneficiary,
    address indexed newBeneficiary
  );

  /// @notice Emitted when a beneficiary claims their earned reward.
  event RewardClaimed(address indexed beneficiary, uint256 amount);

  /// @notice Emitted when this contract is notified of a new reward.
  event RewardNotified(uint256 amount, address notifier);

  /// @notice Emitted when the admin address is set.
  event AdminSet(address indexed oldAdmin, address indexed newAdmin);

  /// @notice Emitted when a reward notifier address is enabled or disabled.
  event RewardNotifierSet(address indexed account, bool isEnabled);

  /// @notice Emitted when a surrogate contract is deployed.
  event SurrogateDeployed(address indexed delegatee, address indexed surrogate);

  /// @notice Thrown when an account attempts a call for which it lacks appropriate permission.
  /// @param reason Human readable code explaining why the call is unauthorized.
  /// @param caller The address that attempted the unauthorized call.
  error UniStaker__Unauthorized(bytes32 reason, address caller);

  /// @notice Thrown if the new rate after a reward notification would be zero.
  error UniStaker__InvalidRewardRate();

  /// @notice Thrown if the following invariant is broken after a new reward: the contract should
  /// always have a reward balance sufficient to distribute at the reward rate across the reward
  /// duration.
  error UniStaker__InsufficientRewardBalance();

  /// @notice Thrown if a caller attempts to specify address zero for certain designated addresses.
  error UniStaker__InvalidAddress();

  /// @notice Thrown when an onBehalf method is called with a deadline that has expired.
  error UniStaker__ExpiredDeadline();

  /// @notice Thrown if a caller supplies an invalid signature to a method that requires one.
  error UniStaker__InvalidSignature();

  /// @notice Metadata associated with a discrete staking deposit.
  /// @param balance The deposit's staked balance.
  /// @param owner The owner of this deposit.
  /// @param delegatee The governance delegate who receives the voting weight for this deposit.
  /// @param beneficiary The address that accrues staking rewards earned by this deposit.
  struct Deposit {
    uint96 balance;
    address owner;
    address delegatee;
    address beneficiary;
  }

  /// @notice Type hash used when encoding data for `stakeOnBehalf` calls.
  bytes32 public constant STAKE_TYPEHASH = keccak256(
    "Stake(uint96 amount,address delegatee,address beneficiary,address depositor,uint256 nonce,uint256 deadline)"
  );
  /// @notice Type hash used when encoding data for `stakeMoreOnBehalf` calls.
  bytes32 public constant STAKE_MORE_TYPEHASH = keccak256(
    "StakeMore(uint256 depositId,uint96 amount,address depositor,uint256 nonce,uint256 deadline)"
  );
  /// @notice Type hash used when encoding data for `alterDelegateeOnBehalf` calls.
  bytes32 public constant ALTER_DELEGATEE_TYPEHASH = keccak256(
    "AlterDelegatee(uint256 depositId,address newDelegatee,address depositor,uint256 nonce,uint256 deadline)"
  );
  /// @notice Type hash used when encoding data for `alterBeneficiaryOnBehalf` calls.
  bytes32 public constant ALTER_BENEFICIARY_TYPEHASH = keccak256(
    "AlterBeneficiary(uint256 depositId,address newBeneficiary,address depositor,uint256 nonce,uint256 deadline)"
  );
  /// @notice Type hash used when encoding data for `withdrawOnBehalf` calls.
  bytes32 public constant WITHDRAW_TYPEHASH = keccak256(
    "Withdraw(uint256 depositId,uint96 amount,address depositor,uint256 nonce,uint256 deadline)"
  );
  /// @notice Type hash used when encoding data for `claimRewardOnBehalf` calls.
  bytes32 public constant CLAIM_REWARD_TYPEHASH =
    keccak256("ClaimReward(address beneficiary,uint256 nonce,uint256 deadline)");

  /// @notice ERC20 token in which rewards are denominated and distributed.
  IERC20 public immutable REWARD_TOKEN;

  /// @notice Delegable governance token which users stake to earn rewards.
  IERC20Delegates public immutable STAKE_TOKEN;

  /// @notice Length of time over which rewards sent to this contract are distributed to stakers.
  uint256 public constant REWARD_DURATION = 30 days;

  /// @notice Scale factor used in reward calculation math to reduce rounding errors caused by
  /// truncation during division.
  uint256 public constant SCALE_FACTOR = 1e36;

  /// @dev Unique identifier that will be used for the next deposit.
  DepositIdentifier private nextDepositId;

  /// @notice Permissioned actor that can enable/disable `rewardNotifier` addresses.
  address public admin;

  /// @notice Global amount currently staked across all deposits.
  uint256 public totalStaked;

  /// @notice Tracks the total staked by a depositor across all unique deposits.
  mapping(address depositor => uint256 amount) public depositorTotalStaked;

  /// @notice Tracks the total stake actively earning rewards for a given beneficiary account.
  mapping(address beneficiary => uint256 amount) public earningPower;

  /// @notice Stores the metadata associated with a given deposit.
  mapping(DepositIdentifier depositId => Deposit deposit) public deposits;

  /// @notice Maps the account of each governance delegate with the surrogate contract which holds
  /// the staked tokens from deposits which assign voting weight to said delegate.
  mapping(address delegatee => DelegationSurrogate surrogate) public surrogates;

  /// @notice Time at which rewards distribution will complete if there are no new rewards.
  uint256 public rewardEndTime;

  /// @notice Last time at which the global rewards accumulator was updated.
  uint256 public lastCheckpointTime;

  /// @notice Global rate at which rewards are currently being distributed to stakers,
  /// denominated in scaled reward tokens per second, using the SCALE_FACTOR.
  uint256 public scaledRewardRate;

  /// @notice Checkpoint value of the global reward per token accumulator.
  uint256 public rewardPerTokenAccumulatedCheckpoint;

  /// @notice Checkpoint of the reward per token accumulator on a per account basis. It represents
  /// the value of the global accumulator at the last time a given beneficiary's rewards were
  /// calculated and stored. The difference between the global value and this value can be
  /// used to calculate the interim rewards earned by given account.
  mapping(address account => uint256) public beneficiaryRewardPerTokenCheckpoint;

  /// @notice Checkpoint of the unclaimed rewards earned by a given beneficiary with the scale
  /// factor included. This value is stored any time an action is taken that specifically impacts
  /// the rate at which rewards are earned by a given beneficiary account. Total unclaimed rewards
  /// for an account are thus this value plus all rewards earned after this checkpoint was taken.
  /// This value is reset to zero when a beneficiary account claims their earned rewards.
  mapping(address account => uint256 amount) public scaledUnclaimedRewardCheckpoint;

  /// @notice Maps addresses to whether they are authorized to call `notifyRewardAmount`.
  mapping(address rewardNotifier => bool) public isRewardNotifier;

  /// @param _rewardToken ERC20 token in which rewards will be denominated.
  /// @param _stakeToken Delegable governance token which users will stake to earn rewards.
  /// @param _admin Address which will have permission to manage rewardNotifiers.
  constructor(IERC20 _rewardToken, IERC20Delegates _stakeToken, address _admin)
    EIP712("TermStaker", "1")
  {
    REWARD_TOKEN = _rewardToken;
    STAKE_TOKEN = _stakeToken;
    _setAdmin(_admin);
  }

  /// @notice Set the admin address.
  /// @param _newAdmin Address of the new admin.
  /// @dev Caller must be the current admin.
  function setAdmin(address _newAdmin) external {
    _revertIfNotAdmin();
    _setAdmin(_newAdmin);
  }

  /// @notice Enables or disables a reward notifier address.
  /// @param _rewardNotifier Address of the reward notifier.
  /// @param _isEnabled `true` to enable the `_rewardNotifier`, or `false` to disable.
  /// @dev Caller must be the current admin.
  function setRewardNotifier(address _rewardNotifier, bool _isEnabled) external {
    _revertIfNotAdmin();
    isRewardNotifier[_rewardNotifier] = _isEnabled;
    emit RewardNotifierSet(_rewardNotifier, _isEnabled);
  }

  /// @notice Timestamp representing the last time at which rewards have been distributed, which is
  /// either the current timestamp (because rewards are still actively being streamed) or the time
  /// at which the reward duration ended (because all rewards to date have already been streamed).
  /// @return Timestamp representing the last time at which rewards have been distributed.
  function lastTimeRewardDistributed() public view returns (uint256) {
    if (rewardEndTime <= block.timestamp) return rewardEndTime;
    else return block.timestamp;
  }

  /// @notice Live value of the global reward per token accumulator. It is the sum of the last
  /// checkpoint value with the live calculation of the value that has accumulated in the interim.
  /// This number should monotonically increase over time as more rewards are distributed.
  /// @return Live value of the global reward per token accumulator.
  function rewardPerTokenAccumulated() public view returns (uint256) {
    if (totalStaked == 0) return rewardPerTokenAccumulatedCheckpoint;

    return rewardPerTokenAccumulatedCheckpoint
      + (scaledRewardRate * (lastTimeRewardDistributed() - lastCheckpointTime)) / totalStaked;
  }

  /// @notice Live value of the unclaimed rewards earned by a given beneficiary account. It is the
  /// sum of the last checkpoint value of their unclaimed rewards with the live calculation of the
  /// rewards that have accumulated for this account in the interim. This value can only increase,
  /// until it is reset to zero once the beneficiary account claims their unearned rewards.
  ///
  /// Note that the contract tracks the unclaimed rewards internally with the scale factor
  /// included, in order to avoid the accrual of precision losses as users takes actions that
  /// cause rewards to be checkpointed. This external helper method is useful for integrations, and
  /// returns the value after it has been scaled down to the reward token's raw decimal amount.
  /// @return Live value of the unclaimed rewards earned by a given beneficiary account.
  function unclaimedReward(address _beneficiary) external view returns (uint256) {
    return _scaledUnclaimedReward(_beneficiary) / SCALE_FACTOR;
  }

  /// @notice Stake tokens to a new deposit. The caller must pre-approve the staking contract to
  /// spend at least the would-be staked amount of the token.
  /// @param _amount The amount of the staking token to stake.
  /// @param _delegatee The address to assign the governance voting weight of the staked tokens.
  /// @return _depositId The unique identifier for this deposit.
  /// @dev The delegatee may not be the zero address. The deposit will be owned by the message
  /// sender, and the beneficiary will also be the message sender.
  function stake(uint96 _amount, address _delegatee)
    external
    returns (DepositIdentifier _depositId)
  {
    _depositId = _stake(msg.sender, _amount, _delegatee, msg.sender);
  }

  /// @notice Method to stake tokens to a new deposit. The caller must pre-approve the staking
  /// contract to spend at least the would-be staked amount of the token.
  /// @param _amount Quantity of the staking token to stake.
  /// @param _delegatee Address to assign the governance voting weight of the staked tokens.
  /// @param _beneficiary Address that will accrue rewards for this stake.
  /// @return _depositId Unique identifier for this deposit.
  /// @dev Neither the delegatee nor the beneficiary may be the zero address. The deposit will be
  /// owned by the message sender.
  function stake(uint96 _amount, address _delegatee, address _beneficiary)
    external
    returns (DepositIdentifier _depositId)
  {
    _depositId = _stake(msg.sender, _amount, _delegatee, _beneficiary);
  }

  /// @notice Method to stake tokens to a new deposit. Before the staking operation occurs, a
  /// signature is passed to the token contract's permit method to spend the would-be staked amount
  /// of the token.
  /// @param _amount Quantity of the staking token to stake.
  /// @param _delegatee Address to assign the governance voting weight of the staked tokens.
  /// @param _beneficiary Address that will accrue rewards for this stake.
  /// @param _deadline The timestamp after which the permit signature should expire.
  /// @param _v ECDSA signature component: Parity of the `y` coordinate of point `R`
  /// @param _r ECDSA signature component: x-coordinate of `R`
  /// @param _s ECDSA signature component: `s` value of the signature
  /// @return _depositId Unique identifier for this deposit.
  /// @dev Neither the delegatee nor the beneficiary may be the zero address. The deposit will be
  /// owned by the message sender.
  function permitAndStake(
    uint96 _amount,
    address _delegatee,
    address _beneficiary,
    uint256 _deadline,
    uint8 _v,
    bytes32 _r,
    bytes32 _s
  ) external returns (DepositIdentifier _depositId) {
    try STAKE_TOKEN.permit(msg.sender, address(this), _amount, _deadline, _v, _r, _s) {} catch {}
    _depositId = _stake(msg.sender, _amount, _delegatee, _beneficiary);
  }

  /// @notice Stake tokens to a new deposit on behalf of a user, using a signature to validate the
  /// user's intent. The caller must pre-approve the staking contract to spend at least the
  /// would-be staked amount of the token.
  /// @param _amount Quantity of the staking token to stake.
  /// @param _delegatee Address to assign the governance voting weight of the staked tokens.
  /// @param _beneficiary Address that will accrue rewards for this stake.
  /// @param _depositor Address of the user on whose behalf this stake is being made.
  /// @param _deadline The timestamp after which the signature should expire.
  /// @param _signature Signature of the user authorizing this stake.
  /// @return _depositId Unique identifier for this deposit.
  /// @dev Neither the delegatee nor the beneficiary may be the zero address.
  function stakeOnBehalf(
    uint96 _amount,
    address _delegatee,
    address _beneficiary,
    address _depositor,
    uint256 _deadline,
    bytes memory _signature
  ) external returns (DepositIdentifier _depositId) {
    _revertIfPastDeadline(_deadline);
    _revertIfSignatureIsNotValidNow(
      _depositor,
      _hashTypedDataV4(
        keccak256(
          abi.encode(
            STAKE_TYPEHASH,
            _amount,
            _delegatee,
            _beneficiary,
            _depositor,
            _useNonce(_depositor),
            _deadline
          )
        )
      ),
      _signature
    );
    _depositId = _stake(_depositor, _amount, _delegatee, _beneficiary);
  }

  /// @notice Add more staking tokens to an existing deposit. A staker should call this method when
  /// they have an existing deposit, and wish to stake more while retaining the same delegatee and
  /// beneficiary.
  /// @param _depositId Unique identifier of the deposit to which stake will be added.
  /// @param _amount Quantity of stake to be added.
  /// @dev The message sender must be the owner of the deposit.
  function stakeMore(DepositIdentifier _depositId, uint96 _amount) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, msg.sender);
    _stakeMore(deposit, _depositId, _amount);
  }

  /// @notice Add more staking tokens to an existing deposit. A staker should call this method when
  /// they have an existing deposit, and wish to stake more while retaining the same delegatee and
  /// beneficiary. Before the staking operation occurs, a signature is passed to the token
  /// contract's permit method to spend the would-be staked amount of the token.
  /// @param _depositId Unique identifier of the deposit to which stake will be added.
  /// @param _amount Quantity of stake to be added.
  /// @param _deadline The timestamp after which the permit signature should expire.
  /// @param _v ECDSA signature component: Parity of the `y` coordinate of point `R`
  /// @param _r ECDSA signature component: x-coordinate of `R`
  /// @param _s ECDSA signature component: `s` value of the signature
  /// @dev The message sender must be the owner of the deposit.
  function permitAndStakeMore(
    DepositIdentifier _depositId,
    uint96 _amount,
    uint256 _deadline,
    uint8 _v,
    bytes32 _r,
    bytes32 _s
  ) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, msg.sender);

    try STAKE_TOKEN.permit(msg.sender, address(this), _amount, _deadline, _v, _r, _s) {} catch {}
    _stakeMore(deposit, _depositId, _amount);
  }

  /// @notice Add more staking tokens to an existing deposit on behalf of a user, using a signature
  /// to validate the user's intent. A staker should call this method when they have an existing
  /// deposit, and wish to stake more while retaining the same delegatee and beneficiary.
  /// @param _depositId Unique identifier of the deposit to which stake will be added.
  /// @param _amount Quantity of stake to be added.
  /// @param _depositor Address of the user on whose behalf this stake is being made.
  /// @param _deadline The timestamp after which the signature should expire.
  /// @param _signature Signature of the user authorizing this stake.
  function stakeMoreOnBehalf(
    DepositIdentifier _depositId,
    uint96 _amount,
    address _depositor,
    uint256 _deadline,
    bytes memory _signature
  ) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, _depositor);
    _revertIfPastDeadline(_deadline);
    _revertIfSignatureIsNotValidNow(
      _depositor,
      _hashTypedDataV4(
        keccak256(
          abi.encode(
            STAKE_MORE_TYPEHASH, _depositId, _amount, _depositor, _useNonce(_depositor), _deadline
          )
        )
      ),
      _signature
    );

    _stakeMore(deposit, _depositId, _amount);
  }

  /// @notice For an existing deposit, change the address to which governance voting power is
  /// assigned.
  /// @param _depositId Unique identifier of the deposit which will have its delegatee altered.
  /// @param _newDelegatee Address of the new governance delegate.
  /// @dev The new delegatee may not be the zero address. The message sender must be the owner of
  /// the deposit.
  function alterDelegatee(DepositIdentifier _depositId, address _newDelegatee) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, msg.sender);
    _alterDelegatee(deposit, _depositId, _newDelegatee);
  }

  /// @notice For an existing deposit, change the address to which governance voting power is
  /// assigned on behalf of a user, using a signature to validate the user's intent.
  /// @param _depositId Unique identifier of the deposit which will have its delegatee altered.
  /// @param _newDelegatee Address of the new governance delegate.
  /// @param _depositor Address of the user on whose behalf this stake is being made.
  /// @param _deadline The timestamp after which the signature should expire.
  /// @param _signature Signature of the user authorizing this stake.
  /// @dev The new delegatee may not be the zero address.
  function alterDelegateeOnBehalf(
    DepositIdentifier _depositId,
    address _newDelegatee,
    address _depositor,
    uint256 _deadline,
    bytes memory _signature
  ) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, _depositor);
    _revertIfPastDeadline(_deadline);
    _revertIfSignatureIsNotValidNow(
      _depositor,
      _hashTypedDataV4(
        keccak256(
          abi.encode(
            ALTER_DELEGATEE_TYPEHASH,
            _depositId,
            _newDelegatee,
            _depositor,
            _useNonce(_depositor),
            _deadline
          )
        )
      ),
      _signature
    );

    _alterDelegatee(deposit, _depositId, _newDelegatee);
  }

  /// @notice For an existing deposit, change the beneficiary to which staking rewards are
  /// accruing.
  /// @param _depositId Unique identifier of the deposit which will have its beneficiary altered.
  /// @param _newBeneficiary Address of the new rewards beneficiary.
  /// @dev The new beneficiary may not be the zero address. The message sender must be the owner of
  /// the deposit.
  function alterBeneficiary(DepositIdentifier _depositId, address _newBeneficiary) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, msg.sender);
    _alterBeneficiary(deposit, _depositId, _newBeneficiary);
  }

  /// @notice For an existing deposit, change the beneficiary to which staking rewards are
  /// accruing on behalf of a user, using a signature to validate the user's intent.
  /// @param _depositId Unique identifier of the deposit which will have its beneficiary altered.
  /// @param _newBeneficiary Address of the new rewards beneficiary.
  /// @param _depositor Address of the user on whose behalf this stake is being made.
  /// @param _deadline The timestamp after which the signature should expire.
  /// @param _signature Signature of the user authorizing this stake.
  /// @dev The new beneficiary may not be the zero address.
  function alterBeneficiaryOnBehalf(
    DepositIdentifier _depositId,
    address _newBeneficiary,
    address _depositor,
    uint256 _deadline,
    bytes memory _signature
  ) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, _depositor);
    _revertIfPastDeadline(_deadline);
    _revertIfSignatureIsNotValidNow(
      _depositor,
      _hashTypedDataV4(
        keccak256(
          abi.encode(
            ALTER_BENEFICIARY_TYPEHASH,
            _depositId,
            _newBeneficiary,
            _depositor,
            _useNonce(_depositor),
            _deadline
          )
        )
      ),
      _signature
    );

    _alterBeneficiary(deposit, _depositId, _newBeneficiary);
  }

  /// @notice Withdraw staked tokens from an existing deposit.
  /// @param _depositId Unique identifier of the deposit from which stake will be withdrawn.
  /// @param _amount Quantity of staked token to withdraw.
  /// @dev The message sender must be the owner of the deposit. Stake is withdrawn to the message
  /// sender's account.
  function withdraw(DepositIdentifier _depositId, uint96 _amount) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, msg.sender);
    _withdraw(deposit, _depositId, _amount);
  }

  /// @notice Withdraw staked tokens from an existing deposit on behalf of a user, using a
  /// signature to validate the user's intent.
  /// @param _depositId Unique identifier of the deposit from which stake will be withdrawn.
  /// @param _amount Quantity of staked token to withdraw.
  /// @param _depositor Address of the user on whose behalf this stake is being made.
  /// @param _deadline The timestamp after which the signature should expire.
  /// @param _signature Signature of the user authorizing this stake.
  /// @dev Stake is withdrawn to the deposit owner's account.
  function withdrawOnBehalf(
    DepositIdentifier _depositId,
    uint96 _amount,
    address _depositor,
    uint256 _deadline,
    bytes memory _signature
  ) external {
    Deposit storage deposit = deposits[_depositId];
    _revertIfNotDepositOwner(deposit, _depositor);
    _revertIfPastDeadline(_deadline);
    _revertIfSignatureIsNotValidNow(
      _depositor,
      _hashTypedDataV4(
        keccak256(
          abi.encode(
            WITHDRAW_TYPEHASH, _depositId, _amount, _depositor, _useNonce(_depositor), _deadline
          )
        )
      ),
      _signature
    );

    _withdraw(deposit, _depositId, _amount);
  }

  /// @notice Claim reward tokens the message sender has earned as a stake beneficiary. Tokens are
  /// sent to the message sender.
  /// @return Amount of reward tokens claimed.
  function claimReward() external returns (uint256) {
    return _claimReward(msg.sender);
  }

  /// @notice Claim earned reward tokens for a beneficiary, using a signature to validate the
  /// beneficiary's intent. Tokens are sent to the beneficiary.
  /// @param _beneficiary Address of the beneficiary who will receive the reward.
  /// @param _deadline The timestamp after which the signature should expire.
  /// @param _signature Signature of the beneficiary authorizing this reward claim.
  /// @return Amount of reward tokens claimed.
  function claimRewardOnBehalf(address _beneficiary, uint256 _deadline, bytes memory _signature)
    external
    returns (uint256)
  {
    _revertIfPastDeadline(_deadline);
    _revertIfSignatureIsNotValidNow(
      _beneficiary,
      _hashTypedDataV4(
        keccak256(
          abi.encode(CLAIM_REWARD_TYPEHASH, _beneficiary, _useNonce(_beneficiary), _deadline)
        )
      ),
      _signature
    );
    return _claimReward(_beneficiary);
  }

  /// @notice Called by an authorized rewards notifier to alert the staking contract that a new
  /// reward has been transferred to it. It is assumed that the reward has already been
  /// transferred to this staking contract before the rewards notifier calls this method.
  /// @param _amount Quantity of reward tokens the staking contract is being notified of.
  /// @dev It is critical that only well behaved contracts are approved by the admin to call this
  /// method, for two reasons.
  ///
  /// 1. A misbehaving contract could grief stakers by frequently notifying this contract of tiny
  ///    rewards, thereby continuously stretching out the time duration over which real rewards are
  ///    distributed. It is required that reward notifiers supply reasonable rewards at reasonable
  ///    intervals.
  //  2. A misbehaving contract could falsely notify this contract of rewards that were not actually
  ///    distributed, creating a shortfall for those claiming their rewards after others. It is
  ///    required that a notifier contract always transfers the `_amount` to this contract before
  ///    calling this method.
  function notifyRewardAmount(uint256 _amount) external {
    if (!isRewardNotifier[msg.sender]) revert UniStaker__Unauthorized("not notifier", msg.sender);

    // We checkpoint the accumulator without updating the timestamp at which it was updated,
    // because that second operation will be done after updating the reward rate.
    rewardPerTokenAccumulatedCheckpoint = rewardPerTokenAccumulated();

    if (block.timestamp >= rewardEndTime) {
      scaledRewardRate = (_amount * SCALE_FACTOR) / REWARD_DURATION;
    } else {
      uint256 _remainingReward = scaledRewardRate * (rewardEndTime - block.timestamp);
      scaledRewardRate = (_remainingReward + _amount * SCALE_FACTOR) / REWARD_DURATION;
    }

    rewardEndTime = block.timestamp + REWARD_DURATION;
    lastCheckpointTime = block.timestamp;

    if ((scaledRewardRate / SCALE_FACTOR) == 0) revert UniStaker__InvalidRewardRate();

    // This check cannot _guarantee_ sufficient rewards have been transferred to the contract,
    // because it cannot isolate the unclaimed rewards owed to stakers left in the balance. While
    // this check is useful for preventing degenerate cases, it is not sufficient. Therefore, it is
    // critical that only safe reward notifier contracts are approved to call this method by the
    // admin.
    if (
      (scaledRewardRate * REWARD_DURATION) > (REWARD_TOKEN.balanceOf(address(this)) * SCALE_FACTOR)
    ) revert UniStaker__InsufficientRewardBalance();

    emit RewardNotified(_amount, msg.sender);
  }

  /// @notice Live value of the unclaimed rewards earned by a given beneficiary account with the
  /// scale factor included. Used internally for calculating reward checkpoints while minimizing
  /// precision loss.
  /// @return Live value of the unclaimed rewards earned by a given beneficiary account with the
  /// scale factor included.
  /// @dev See documentation for the public, non-scaled `unclaimedReward` method for more details.
  function _scaledUnclaimedReward(address _beneficiary) internal view returns (uint256) {
    return scaledUnclaimedRewardCheckpoint[_beneficiary]
      + (
        earningPower[_beneficiary]
          * (rewardPerTokenAccumulated() - beneficiaryRewardPerTokenCheckpoint[_beneficiary])
      );
  }

  /// @notice Allows an address to increment their nonce and therefore invalidate any pending signed
  /// actions.
  function invalidateNonce() external {
    _useNonce(msg.sender);
  }

  /// @notice Internal method which finds the existing surrogate contract—or deploys a new one if
  /// none exists—for a given delegatee.
  /// @param _delegatee Account for which a surrogate is sought.
  /// @return _surrogate The address of the surrogate contract for the delegatee.
  function _fetchOrDeploySurrogate(address _delegatee)
    internal
    returns (DelegationSurrogate _surrogate)
  {
    _surrogate = surrogates[_delegatee];

    if (address(_surrogate) == address(0)) {
      _surrogate = new DelegationSurrogate(STAKE_TOKEN, _delegatee);
      surrogates[_delegatee] = _surrogate;
      emit SurrogateDeployed(_delegatee, address(_surrogate));
    }
  }

  /// @notice Internal convenience method which calls the `transferFrom` method on the stake token
  /// contract and reverts on failure.
  /// @param _from Source account from which stake token is to be transferred.
  /// @param _to Destination account of the stake token which is to be transferred.
  /// @param _value Quantity of stake token which is to be transferred.
  function _stakeTokenSafeTransferFrom(address _from, address _to, uint256 _value) internal {
    SafeERC20.safeTransferFrom(IERC20(address(STAKE_TOKEN)), _from, _to, _value);
  }

  /// @notice Internal method which generates and returns a unique, previously unused deposit
  /// identifier.
  /// @return _depositId Previously unused deposit identifier.
  function _useDepositId() internal returns (DepositIdentifier _depositId) {
    _depositId = nextDepositId;
    nextDepositId = DepositIdentifier.wrap(DepositIdentifier.unwrap(_depositId) + 1);
  }

  /// @notice Internal convenience methods which performs the staking operations.
  /// @dev This method must only be called after proper authorization has been completed.
  /// @dev See public stake methods for additional documentation.
  function _stake(address _depositor, uint96 _amount, address _delegatee, address _beneficiary)
    internal
    returns (DepositIdentifier _depositId)
  {
    _revertIfAddressZero(_delegatee);
    _revertIfAddressZero(_beneficiary);

    _checkpointGlobalReward();
    _checkpointReward(_beneficiary);

    DelegationSurrogate _surrogate = _fetchOrDeploySurrogate(_delegatee);
    _depositId = _useDepositId();

    totalStaked += _amount;
    depositorTotalStaked[_depositor] += _amount;
    earningPower[_beneficiary] += _amount;
    deposits[_depositId] = Deposit({
      balance: _amount,
      owner: _depositor,
      delegatee: _delegatee,
      beneficiary: _beneficiary
    });
    _stakeTokenSafeTransferFrom(_depositor, address(_surrogate), _amount);
    emit StakeDeposited(_depositor, _depositId, _amount, _amount);
    emit BeneficiaryAltered(_depositId, address(0), _beneficiary);
    emit DelegateeAltered(_depositId, address(0), _delegatee);
  }

  /// @notice Internal convenience method which adds more stake to an existing deposit.
  /// @dev This method must only be called after proper authorization has been completed.
  /// @dev See public stakeMore methods for additional documentation.
  function _stakeMore(Deposit storage deposit, DepositIdentifier _depositId, uint96 _amount)
    internal
  {
    _checkpointGlobalReward();
    _checkpointReward(deposit.beneficiary);

    DelegationSurrogate _surrogate = surrogates[deposit.delegatee];

    totalStaked += _amount;
    depositorTotalStaked[deposit.owner] += _amount;
    earningPower[deposit.beneficiary] += _amount;
    deposit.balance += _amount;
    _stakeTokenSafeTransferFrom(deposit.owner, address(_surrogate), _amount);
    emit StakeDeposited(deposit.owner, _depositId, _amount, deposit.balance);
  }

  /// @notice Internal convenience method which alters the delegatee of an existing deposit.
  /// @dev This method must only be called after proper authorization has been completed.
  /// @dev See public alterDelegatee methods for additional documentation.
  function _alterDelegatee(
    Deposit storage deposit,
    DepositIdentifier _depositId,
    address _newDelegatee
  ) internal {
    _revertIfAddressZero(_newDelegatee);
    DelegationSurrogate _oldSurrogate = surrogates[deposit.delegatee];
    emit DelegateeAltered(_depositId, deposit.delegatee, _newDelegatee);
    deposit.delegatee = _newDelegatee;
    DelegationSurrogate _newSurrogate = _fetchOrDeploySurrogate(_newDelegatee);
    _stakeTokenSafeTransferFrom(address(_oldSurrogate), address(_newSurrogate), deposit.balance);
  }

  /// @notice Internal convenience method which alters the beneficiary of an existing deposit.
  /// @dev This method must only be called after proper authorization has been completed.
  /// @dev See public alterBeneficiary methods for additional documentation.
  function _alterBeneficiary(
    Deposit storage deposit,
    DepositIdentifier _depositId,
    address _newBeneficiary
  ) internal {
    _revertIfAddressZero(_newBeneficiary);
    _checkpointGlobalReward();
    _checkpointReward(deposit.beneficiary);
    earningPower[deposit.beneficiary] -= deposit.balance;

    _checkpointReward(_newBeneficiary);
    emit BeneficiaryAltered(_depositId, deposit.beneficiary, _newBeneficiary);
    deposit.beneficiary = _newBeneficiary;
    earningPower[_newBeneficiary] += deposit.balance;
  }

  /// @notice Internal convenience method which withdraws the stake from an existing deposit.
  /// @dev This method must only be called after proper authorization has been completed.
  /// @dev See public withdraw methods for additional documentation.
  function _withdraw(Deposit storage deposit, DepositIdentifier _depositId, uint96 _amount)
    internal
  {
    _checkpointGlobalReward();
    _checkpointReward(deposit.beneficiary);

    deposit.balance -= _amount; // overflow prevents withdrawing more than balance
    totalStaked -= _amount;
    depositorTotalStaked[deposit.owner] -= _amount;
    earningPower[deposit.beneficiary] -= _amount;
    _stakeTokenSafeTransferFrom(address(surrogates[deposit.delegatee]), deposit.owner, _amount);
    emit StakeWithdrawn(_depositId, _amount, deposit.balance);
  }

  /// @notice Internal convenience method which claims earned rewards.
  /// @return Amount of reward tokens claimed.
  /// @dev This method must only be called after proper authorization has been completed.
  /// @dev See public claimReward methods for additional documentation.
  function _claimReward(address _beneficiary) internal returns (uint256) {
    _checkpointGlobalReward();
    _checkpointReward(_beneficiary);

    uint256 _reward = scaledUnclaimedRewardCheckpoint[_beneficiary] / SCALE_FACTOR;
    if (_reward == 0) return 0;

    // retain sub-wei dust that would be left due to the precision loss
    scaledUnclaimedRewardCheckpoint[_beneficiary] =
      scaledUnclaimedRewardCheckpoint[_beneficiary] - (_reward * SCALE_FACTOR);
    emit RewardClaimed(_beneficiary, _reward);

    SafeERC20.safeTransfer(REWARD_TOKEN, _beneficiary, _reward);
    return _reward;
  }

  /// @notice Checkpoints the global reward per token accumulator.
  function _checkpointGlobalReward() internal {
    rewardPerTokenAccumulatedCheckpoint = rewardPerTokenAccumulated();
    lastCheckpointTime = lastTimeRewardDistributed();
  }

  /// @notice Checkpoints the unclaimed rewards and reward per token accumulator of a given
  /// beneficiary account.
  /// @param _beneficiary The account for which reward parameters will be checkpointed.
  /// @dev This is a sensitive internal helper method that must only be called after global rewards
  /// accumulator has been checkpointed. It assumes the global `rewardPerTokenCheckpoint` is up to
  /// date.
  function _checkpointReward(address _beneficiary) internal {
    scaledUnclaimedRewardCheckpoint[_beneficiary] = _scaledUnclaimedReward(_beneficiary);
    beneficiaryRewardPerTokenCheckpoint[_beneficiary] = rewardPerTokenAccumulatedCheckpoint;
  }

  /// @notice Internal helper method which sets the admin address.
  /// @param _newAdmin Address of the new admin.
  function _setAdmin(address _newAdmin) internal {
    _revertIfAddressZero(_newAdmin);
    emit AdminSet(admin, _newAdmin);
    admin = _newAdmin;
  }

  /// @notice Internal helper method which reverts UniStaker__Unauthorized if the message sender is
  /// not the admin.
  function _revertIfNotAdmin() internal view {
    if (msg.sender != admin) revert UniStaker__Unauthorized("not admin", msg.sender);
  }

  /// @notice Internal helper method which reverts UniStaker__Unauthorized if the alleged owner is
  /// not the true owner of the deposit.
  /// @param deposit Deposit to validate.
  /// @param owner Alleged owner of deposit.
  function _revertIfNotDepositOwner(Deposit storage deposit, address owner) internal view {
    if (owner != deposit.owner) revert UniStaker__Unauthorized("not owner", owner);
  }

  /// @notice Internal helper method which reverts with UniStaker__InvalidAddress if the account in
  /// question is address zero.
  /// @param _account Account to verify.
  function _revertIfAddressZero(address _account) internal pure {
    if (_account == address(0)) revert UniStaker__InvalidAddress();
  }

  function _revertIfPastDeadline(uint256 _deadline) internal view {
    if (block.timestamp > _deadline) revert UniStaker__ExpiredDeadline();
  }

  /// @notice Internal helper method which reverts with UniStaker__InvalidSignature if the signature
  /// is invalid.
  /// @param _signer Address of the signer.
  /// @param _hash Hash of the message.
  /// @param _signature Signature to validate.
  function _revertIfSignatureIsNotValidNow(address _signer, bytes32 _hash, bytes memory _signature)
    internal
    view
  {
    bool _isValid = SignatureChecker.isValidSignatureNow(_signer, _hash, _signature);
    if (!_isValid) revert UniStaker__InvalidSignature();
  }
}

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.23;

/// @notice A subset of the ERC20Votes-style governance token to which UNI conforms.
/// Methods related to standard ERC20 functionality and to delegation are included.
/// These methods are needed in the context of this system. Methods related to check pointing,
/// past voting weights, and other functionality are omitted.
interface IERC20Delegates {
  // ERC20 related methods
  function allowance(address account, address spender) external view returns (uint256);
  function approve(address spender, uint256 rawAmount) external returns (bool);
  function balanceOf(address account) external view returns (uint256);
  function decimals() external view returns (uint8);
  function symbol() external view returns (string memory);
  function totalSupply() external view returns (uint256);
  function transfer(address dst, uint256 rawAmount) external returns (bool);
  function transferFrom(address src, address dst, uint256 rawAmount) external returns (bool);
  function permit(
    address owner,
    address spender,
    uint256 rawAmount,
    uint256 deadline,
    uint8 v,
    bytes32 r,
    bytes32 s
  ) external;

  // ERC20Votes delegation methods
  function delegate(address delegatee) external;
  function delegates(address) external view returns (address);
}

// SPDX-License-Identifier: AGPL-3.0-only
pragma solidity ^0.8.23;

/// @title INotifiableRewardReceiver
/// @author ScopeLift
/// @notice The communication interface between the V3FactoryOwner contract and the UniStaker
/// contract. In particular, the V3FactoryOwner only needs to know the latter implements the
/// specified method in order to forward payouts to the UniStaker contract. The UniStaker contract
/// receives the rewards and abstracts the distribution mechanics
interface INotifiableRewardReceiver {
  /// @notice Method called to notify a reward receiver it has received a reward.
  /// @param _amount The amount of reward.
  function notifyRewardAmount(uint256 _amount) external;
}