Contract Address Details

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/utils/ERC721Holder.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";

/// @title SpunkStaking v10 — Rug-proof. Designed for ownership renouncement.
/// @notice Stake Spunk NFTs, earn SPUNK ERC-20 from a pre-funded reward pool.
///         Staking is blocked when the available reward pool is empty.
///
/// Rug-proof design:
///   - No withdrawRewardPool — deposited rewards stay for stakers
///   - No pause — contract runs forever
///   - setRewardPerDay bounded [1, 1000] SPUNK/day — can never be zeroed
///   - emergencyUnstake (admin) claims rewards + returns NFTs to stakers
///   - Users can ALWAYS exit via emergencyRelease (bypasses lock, race lock)
///   - Owner can renounceOwnership() after setup for full trustlessness
///
/// v10 fixes (from v9 audit):
///   - [M-1] Accumulator-based rewards — unlimited rate changes without corruption
///   - [M-2] emergencyRelease partial — forfeits pro-rata share for released tokens only
///   - [M-3] availableRewardPool() — subtracts committed (accrued but unclaimed) rewards
contract SpunkStaking is ERC721Holder, Ownable, ReentrancyGuard {
    using SafeERC20 for IERC20;

    IERC721 public immutable spunksNFT;
    IERC20 public immutable spunkCoin;

    // ── Constants ──
    uint256 public constant MAX_STAKED = 20;
    uint256 public constant MAX_REWARD_PER_DAY = 1000 ether;
    uint256 public constant MIN_REWARD_PER_DAY = 1 ether;

    // ── State ──
    uint256 public rewardPerDay = 10 ether;
    uint256 public totalDistributed;
    uint256 public lockPeriod = 3 days;

    // ── Reward accumulator (replaces single checkpoint — FIX v9-M1) ──
    // Each NFT earns `rewardPerDay / 86400` wei per second.  The accumulator
    // tracks the cumulative per-NFT reward since the contract was deployed.
    // On every rate change or user interaction the accumulator is checkpointed,
    // so an arbitrary number of rate changes are handled correctly.
    uint256 public rewardPerTokenStored;
    uint256 public lastRewardUpdateTime;
    uint256 public totalStakedNFTs;
    uint256 public totalCommittedRewards;  // FIX v9-M3

    mapping(address => uint256) public userRewardPerTokenPaid;
    mapping(address => uint256) public rewardsAccrued;

    struct StakeInfo {
        address owner;
        uint48 stakedAt;
        uint48 effectiveLock;
    }

    mapping(uint256 => StakeInfo) public stakes;
    mapping(address => uint256[]) private _stakedTokens;

    // ── Leaderboard ──
    struct UserStats {
        uint256 totalClaimed;
        uint256 totalStakeTime;
        uint256 currentStreak;
    }
    mapping(address => UserStats) public userStats;
    address[] public leaderboardUsers;
    mapping(address => bool) private _isLeaderboardUser;

    address public raceContract;
    mapping(uint256 => bool) public lockedByRace;

    // ── Events ──
    event Staked(address indexed user, uint256[] tokenIds);
    event Unstaked(address indexed user, uint256[] tokenIds);
    event Claimed(address indexed user, uint256 amount);
    event RewardPerDayChanged(uint256 oldRate, uint256 newRate);
    event LockPeriodChanged(uint256 oldPeriod, uint256 newPeriod);
    event RaceContractChanged(address oldAddr, address newAddr);
    event FundsDeposited(address indexed from, uint256 amount);

    constructor(address _spunks, address _spunkCoin) Ownable(msg.sender) {
        spunksNFT = IERC721(_spunks);
        spunkCoin = IERC20(_spunkCoin);
        lastRewardUpdateTime = block.timestamp;
    }

    // ══════════════════════════════════════
    //  ACCUMULATOR INTERNALS
    // ══════════════════════════════════════

    /// @dev Current cumulative reward per NFT, including elapsed time since last checkpoint.
    function _rewardPerToken() internal view returns (uint256) {
        if (block.timestamp <= lastRewardUpdateTime) return rewardPerTokenStored;
        return rewardPerTokenStored
            + ((block.timestamp - lastRewardUpdateTime) * rewardPerDay) / 1 days;
    }

    /// @dev Checkpoint the global accumulator and snapshot a user's pending rewards.
    ///      Pass address(0) to checkpoint only the global state (e.g. on rate change).
    function _updateReward(address user) internal {
        uint256 rpt = _rewardPerToken();

        // Track new global commitment for all stakers
        if (block.timestamp > lastRewardUpdateTime && totalStakedNFTs > 0) {
            uint256 newGlobal =
                (totalStakedNFTs * (block.timestamp - lastRewardUpdateTime) * rewardPerDay) / 1 days;
            totalCommittedRewards += newGlobal;
        }

        rewardPerTokenStored = rpt;
        lastRewardUpdateTime = block.timestamp;

        if (user != address(0)) {
            uint256 staked = _stakedTokens[user].length;
            if (staked > 0) {
                rewardsAccrued[user] += staked * (rpt - userRewardPerTokenPaid[user]);
            }
            userRewardPerTokenPaid[user] = rpt;
        }
    }

    /// @dev Transfer accrued rewards to the user.  If the pool is insolvent the
    ///      payout is capped at the available balance (excess is lost — same as v9).
    function _payRewards(address user) internal {
        uint256 pending = rewardsAccrued[user];
        if (pending == 0) return;

        rewardsAccrued[user] = 0;
        _reduceCommitted(pending);

        uint256 pool = rewardPoolBalance();
        uint256 payout = pending > pool ? pool : pending;

        if (payout > 0) {
            spunkCoin.safeTransfer(user, payout);
            totalDistributed += payout;
            userStats[user].totalClaimed += payout;
            emit Claimed(user, payout);
        }
    }

    /// @dev Forfeit `amount` of a user's accrued rewards (returns them to the available pool).
    function _forfeitRewards(address user, uint256 amount) internal {
        if (amount > rewardsAccrued[user]) amount = rewardsAccrued[user];
        rewardsAccrued[user] -= amount;
        _reduceCommitted(amount);
    }

    /// @dev Safely decrease totalCommittedRewards (guards against rounding underflow).
    function _reduceCommitted(uint256 amount) internal {
        if (amount >= totalCommittedRewards) {
            totalCommittedRewards = 0;
        } else {
            totalCommittedRewards -= amount;
        }
    }

    // ══════════════════════════════════════
    //  REWARD POOL
    // ══════════════════════════════════════

    /// @notice Raw SPUNK balance held by this contract.
    function rewardPoolBalance() public view returns (uint256) {
        return spunkCoin.balanceOf(address(this));
    }

    /// @notice Effective available pool = balance minus accrued-but-unclaimed rewards.
    ///         Use this instead of rewardPoolBalance() to gauge real runway.
    function availableRewardPool() public view returns (uint256) {
        uint256 balance = spunkCoin.balanceOf(address(this));
        uint256 pendingGlobal = 0;
        if (block.timestamp > lastRewardUpdateTime && totalStakedNFTs > 0) {
            pendingGlobal =
                (totalStakedNFTs * (block.timestamp - lastRewardUpdateTime) * rewardPerDay) / 1 days;
        }
        uint256 committed = totalCommittedRewards + pendingGlobal;
        if (committed >= balance) return 0;
        return balance - committed;
    }

    function depositRewards(uint256 amount) external {
        require(amount > 0, "Zero");
        spunkCoin.safeTransferFrom(msg.sender, address(this), amount);
        emit FundsDeposited(msg.sender, amount);
    }

    // ══════════════════════════════════════
    //  STAKING
    // ══════════════════════════════════════

    function stake(uint256[] calldata tokenIds) external nonReentrant {
        require(tokenIds.length > 0, "Empty");
        require(availableRewardPool() > 0, "Reward pool empty");
        require(
            _stakedTokens[msg.sender].length + tokenIds.length <= MAX_STAKED,
            "Max 20 staked"
        );

        _updateReward(msg.sender);
        _payRewards(msg.sender);

        if (!_isLeaderboardUser[msg.sender]) {
            _isLeaderboardUser[msg.sender] = true;
            leaderboardUsers.push(msg.sender);
        }
        if (_stakedTokens[msg.sender].length == 0) {
            userStats[msg.sender].currentStreak = block.timestamp;
        }

        for (uint256 i = 0; i < tokenIds.length; i++) {
            for (uint256 j = i + 1; j < tokenIds.length; j++) {
                require(tokenIds[i] != tokenIds[j], "Duplicate");
            }
            spunksNFT.transferFrom(msg.sender, address(this), tokenIds[i]);
            stakes[tokenIds[i]] = StakeInfo(msg.sender, uint48(block.timestamp), uint48(lockPeriod));
            _stakedTokens[msg.sender].push(tokenIds[i]);
        }

        totalStakedNFTs += tokenIds.length;
        emit Staked(msg.sender, tokenIds);
    }

    function unstake(uint256[] calldata tokenIds) external nonReentrant {
        require(tokenIds.length > 0, "Empty");

        _updateReward(msg.sender);
        _payRewards(msg.sender);

        for (uint256 i = 0; i < tokenIds.length; i++) {
            StakeInfo memory info = stakes[tokenIds[i]];
            require(info.owner == msg.sender, "Not yours");
            require(!lockedByRace[tokenIds[i]], "In active race");
            require(
                block.timestamp >= uint256(info.stakedAt) + uint256(info.effectiveLock),
                "Lock period active"
            );
            userStats[msg.sender].totalStakeTime += block.timestamp - uint256(info.stakedAt);
            delete stakes[tokenIds[i]];
            _removeFromArray(_stakedTokens[msg.sender], tokenIds[i]);
        }

        totalStakedNFTs -= tokenIds.length;

        if (_stakedTokens[msg.sender].length == 0) {
            userStats[msg.sender].currentStreak = 0;
        }

        for (uint256 i = 0; i < tokenIds.length; i++) {
            spunksNFT.safeTransferFrom(address(this), msg.sender, tokenIds[i]);
        }

        emit Unstaked(msg.sender, tokenIds);
    }

    /// @notice Force unstake — forfeits ALL pending rewards, still enforces lock period.
    function forceUnstake(uint256[] calldata tokenIds) external nonReentrant {
        require(tokenIds.length > 0, "Empty");

        _updateReward(msg.sender);
        _forfeitRewards(msg.sender, rewardsAccrued[msg.sender]);

        for (uint256 i = 0; i < tokenIds.length; i++) {
            StakeInfo memory info = stakes[tokenIds[i]];
            require(info.owner == msg.sender, "Not yours");
            require(!lockedByRace[tokenIds[i]], "In active race");
            require(
                block.timestamp >= uint256(info.stakedAt) + uint256(info.effectiveLock),
                "Lock period active"
            );
            userStats[msg.sender].totalStakeTime += block.timestamp - uint256(info.stakedAt);
            delete stakes[tokenIds[i]];
            _removeFromArray(_stakedTokens[msg.sender], tokenIds[i]);
        }

        totalStakedNFTs -= tokenIds.length;

        if (_stakedTokens[msg.sender].length == 0) {
            userStats[msg.sender].currentStreak = 0;
        }
        for (uint256 i = 0; i < tokenIds.length; i++) {
            spunksNFT.safeTransferFrom(address(this), msg.sender, tokenIds[i]);
        }

        emit Unstaked(msg.sender, tokenIds);
    }

    /// @notice User emergency exit — bypasses lock period AND race lock.
    /// Partial release: forfeits pro-rata rewards for released tokens, pays the rest.
    /// Full release: forfeits all rewards.
    /// FIX v9-M2: no longer overpays on partial release.
    function emergencyRelease(uint256[] calldata tokenIds) external nonReentrant {
        require(tokenIds.length > 0, "Empty");

        _updateReward(msg.sender);
        uint256 stakedBefore = _stakedTokens[msg.sender].length;

        if (tokenIds.length < stakedBefore) {
            // Partial — forfeit only the released tokens' share, pay the rest
            uint256 forfeit = (rewardsAccrued[msg.sender] * tokenIds.length) / stakedBefore;
            _forfeitRewards(msg.sender, forfeit);
            _payRewards(msg.sender);
        } else {
            // Full release — forfeit everything
            _forfeitRewards(msg.sender, rewardsAccrued[msg.sender]);
        }

        for (uint256 i = 0; i < tokenIds.length; i++) {
            require(stakes[tokenIds[i]].owner == msg.sender, "Not yours");
            lockedByRace[tokenIds[i]] = false;
            userStats[msg.sender].totalStakeTime +=
                block.timestamp - uint256(stakes[tokenIds[i]].stakedAt);
            delete stakes[tokenIds[i]];
            _removeFromArray(_stakedTokens[msg.sender], tokenIds[i]);
        }

        totalStakedNFTs -= tokenIds.length;

        if (_stakedTokens[msg.sender].length == 0) {
            userStats[msg.sender].currentStreak = 0;
        }
        for (uint256 i = 0; i < tokenIds.length; i++) {
            spunksNFT.safeTransferFrom(address(this), msg.sender, tokenIds[i]);
        }

        emit Unstaked(msg.sender, tokenIds);
    }

    /// @notice Claim accrued rewards. Always callable — no admin gate.
    function claimRewards() external nonReentrant {
        _updateReward(msg.sender);
        _payRewards(msg.sender);
    }

    /// @notice View: total pending rewards for a user (including un-checkpointed time).
    function pendingRewards(address user) public view returns (uint256) {
        uint256 staked = _stakedTokens[user].length;
        uint256 rpt = _rewardPerToken();
        uint256 newRewards = staked * (rpt - userRewardPerTokenPaid[user]);
        return rewardsAccrued[user] + newRewards;
    }

    function getStakedTokens(address user) external view returns (uint256[] memory) {
        return _stakedTokens[user];
    }

    function stakeOwner(uint256 tokenId) external view returns (address) {
        return stakes[tokenId].owner;
    }

    function lockTimeRemaining(uint256 tokenId) external view returns (uint256) {
        StakeInfo memory info = stakes[tokenId];
        if (info.owner == address(0)) return 0;
        uint256 unlockAt = uint256(info.stakedAt) + uint256(info.effectiveLock);
        if (block.timestamp >= unlockAt) return 0;
        return unlockAt - block.timestamp;
    }

    // ══════════════════════════════════════
    //  LEADERBOARD
    // ══════════════════════════════════════

    function leaderboardLength() external view returns (uint256) {
        return leaderboardUsers.length;
    }

    function getLeaderboard(uint256 offset, uint256 limit)
        external
        view
        returns (
            address[] memory users,
            uint256[] memory claimed,
            uint256[] memory stakeTime,
            uint256[] memory streaks
        )
    {
        uint256 len = leaderboardUsers.length;
        if (offset >= len) {
            return (new address[](0), new uint256[](0), new uint256[](0), new uint256[](0));
        }
        uint256 end = offset + limit;
        if (end > len) end = len;
        uint256 size = end - offset;

        users = new address[](size);
        claimed = new uint256[](size);
        stakeTime = new uint256[](size);
        streaks = new uint256[](size);

        for (uint256 i = 0; i < size; i++) {
            address u = leaderboardUsers[offset + i];
            users[i] = u;
            claimed[i] = userStats[u].totalClaimed;
            stakeTime[i] = userStats[u].totalStakeTime;
            streaks[i] = userStats[u].currentStreak;
        }
    }

    // ══════════════════════════════════════
    //  RACE CONTRACT INTERFACE
    // ══════════════════════════════════════

    function lockForRace(uint256 tokenId) external {
        require(msg.sender == raceContract, "Only race contract");
        require(stakes[tokenId].owner != address(0), "Not staked");
        lockedByRace[tokenId] = true;
    }

    function unlockFromRace(uint256 tokenId) external {
        require(msg.sender == raceContract, "Only race contract");
        lockedByRace[tokenId] = false;
    }

    // ══════════════════════════════════════
    //  ADMIN
    // ══════════════════════════════════════

    /// @notice Change reward rate.  The accumulator is checkpointed first so all
    ///         prior accrual is locked in at the old rate.  Supports unlimited
    ///         consecutive rate changes without reward corruption (FIX v9-M1).
    function setRewardPerDay(uint256 _rate) external onlyOwner {
        require(_rate >= MIN_REWARD_PER_DAY, "Below minimum");
        require(_rate <= MAX_REWARD_PER_DAY, "Too high");
        _updateReward(address(0));
        emit RewardPerDayChanged(rewardPerDay, _rate);
        rewardPerDay = _rate;
    }

    /// @notice Only affects future stakes — existing stakes keep their original lock.
    function setLockPeriod(uint256 _period) external onlyOwner {
        require(_period <= 30 days, "Max 30 days");
        emit LockPeriodChanged(lockPeriod, _period);
        lockPeriod = _period;
    }

    function setRaceContract(address _race) external onlyOwner {
        emit RaceContractChanged(raceContract, _race);
        raceContract = _race;
    }

    /// @notice Owner emergency unstake — claims rewards for stakers + returns NFTs.
    function emergencyUnstake(uint256[] calldata tokenIds) external onlyOwner nonReentrant {
        for (uint256 i = 0; i < tokenIds.length; i++) {
            address staker = stakes[tokenIds[i]].owner;
            if (staker != address(0)) {
                _updateReward(staker);
                _payRewards(staker);

                userStats[staker].totalStakeTime +=
                    block.timestamp - uint256(stakes[tokenIds[i]].stakedAt);

                lockedByRace[tokenIds[i]] = false;
                delete stakes[tokenIds[i]];
                _removeFromArray(_stakedTokens[staker], tokenIds[i]);
                totalStakedNFTs--;

                if (_stakedTokens[staker].length == 0) {
                    userStats[staker].currentStreak = 0;
                }

                spunksNFT.safeTransferFrom(address(this), staker, tokenIds[i]);
            }
        }
    }

    function _removeFromArray(uint256[] storage arr, uint256 val) internal {
        for (uint256 i = 0; i < arr.length; i++) {
            if (arr[i] == val) {
                arr[i] = arr[arr.length - 1];
                arr.pop();
                return;
            }
        }
    }
}
        

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (utils/introspection/IERC165.sol)

pragma solidity >=0.4.16;

/**
 * @dev Interface of the ERC-165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[ERC].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[ERC section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/ReentrancyGuard.sol)

pragma solidity ^0.8.20;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If EIP-1153 (transient storage) is available on the chain you're deploying at,
 * consider using {ReentrancyGuardTransient} instead.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant NOT_ENTERED = 1;
    uint256 private constant ENTERED = 2;

    uint256 private _status;

    /**
     * @dev Unauthorized reentrant call.
     */
    error ReentrancyGuardReentrantCall();

    constructor() {
        _status = NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be NOT_ENTERED
        if (_status == ENTERED) {
            revert ReentrancyGuardReentrantCall();
        }

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

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

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == ENTERED;
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

pragma solidity ^0.8.20;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

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

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC721/utils/ERC721Holder.sol)

pragma solidity ^0.8.20;

import {IERC721Receiver} from "../IERC721Receiver.sol";

/**
 * @dev Implementation of the {IERC721Receiver} interface.
 *
 * Accepts all token transfers.
 * Make sure the contract is able to use its token with {IERC721-safeTransferFrom}, {IERC721-approve} or
 * {IERC721-setApprovalForAll}.
 */
abstract contract ERC721Holder is IERC721Receiver {
    /**
     * @dev See {IERC721Receiver-onERC721Received}.
     *
     * Always returns `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(address, address, uint256, bytes memory) public virtual returns (bytes4) {
        return this.onERC721Received.selector;
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity >=0.5.0;

/**
 * @title ERC-721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC-721 asset contracts.
 */
interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be
     * reverted.
     *
     * The selector can be obtained in Solidity with `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC721/IERC721.sol)

pragma solidity >=0.6.2;

import {IERC165} from "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC-721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC-721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or
     *   {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC-721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the address zero.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.3.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "../IERC20.sol";
import {IERC1363} from "../../../interfaces/IERC1363.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC-20 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 {
    /**
     * @dev An operation with an ERC-20 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 Variant of {safeTransfer} that returns a bool instead of reverting if the operation is not successful.
     */
    function trySafeTransfer(IERC20 token, address to, uint256 value) internal returns (bool) {
        return _callOptionalReturnBool(token, abi.encodeCall(token.transfer, (to, value)));
    }

    /**
     * @dev Variant of {safeTransferFrom} that returns a bool instead of reverting if the operation is not successful.
     */
    function trySafeTransferFrom(IERC20 token, address from, address to, uint256 value) internal returns (bool) {
        return _callOptionalReturnBool(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.
     *
     * IMPORTANT: If the token implements ERC-7674 (ERC-20 with temporary allowance), and if the "client"
     * smart contract uses ERC-7674 to set temporary allowances, then the "client" smart contract should avoid using
     * this function. Performing a {safeIncreaseAllowance} or {safeDecreaseAllowance} operation on a token contract
     * that has a non-zero temporary allowance (for that particular owner-spender) will result in unexpected behavior.
     */
    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.
     *
     * IMPORTANT: If the token implements ERC-7674 (ERC-20 with temporary allowance), and if the "client"
     * smart contract uses ERC-7674 to set temporary allowances, then the "client" smart contract should avoid using
     * this function. Performing a {safeIncreaseAllowance} or {safeDecreaseAllowance} operation on a token contract
     * that has a non-zero temporary allowance (for that particular owner-spender) will result in unexpected behavior.
     */
    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.
     *
     * NOTE: If the token implements ERC-7674, this function will not modify any temporary allowance. This function
     * only sets the "standard" allowance. Any temporary allowance will remain active, in addition to the value being
     * set here.
     */
    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 Performs an {ERC1363} transferAndCall, with a fallback to the simple {ERC20} transfer if the target has no
     * code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * Reverts if the returned value is other than `true`.
     */
    function transferAndCallRelaxed(IERC1363 token, address to, uint256 value, bytes memory data) internal {
        if (to.code.length == 0) {
            safeTransfer(token, to, value);
        } else if (!token.transferAndCall(to, value, data)) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @dev Performs an {ERC1363} transferFromAndCall, with a fallback to the simple {ERC20} transferFrom if the target
     * has no code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * Reverts if the returned value is other than `true`.
     */
    function transferFromAndCallRelaxed(
        IERC1363 token,
        address from,
        address to,
        uint256 value,
        bytes memory data
    ) internal {
        if (to.code.length == 0) {
            safeTransferFrom(token, from, to, value);
        } else if (!token.transferFromAndCall(from, to, value, data)) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @dev Performs an {ERC1363} approveAndCall, with a fallback to the simple {ERC20} approve if the target has no
     * code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * NOTE: When the recipient address (`to`) has no code (i.e. is an EOA), this function behaves as {forceApprove}.
     * Opposedly, when the recipient address (`to`) has code, this function only attempts to call {ERC1363-approveAndCall}
     * once without retrying, and relies on the returned value to be true.
     *
     * Reverts if the returned value is other than `true`.
     */
    function approveAndCallRelaxed(IERC1363 token, address to, uint256 value, bytes memory data) internal {
        if (to.code.length == 0) {
            forceApprove(token, to, value);
        } else if (!token.approveAndCall(to, value, data)) {
            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 {_callOptionalReturnBool} that reverts if call fails to meet the requirements.
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        uint256 returnSize;
        uint256 returnValue;
        assembly ("memory-safe") {
            let success := call(gas(), token, 0, add(data, 0x20), mload(data), 0, 0x20)
            // bubble errors
            if iszero(success) {
                let ptr := mload(0x40)
                returndatacopy(ptr, 0, returndatasize())
                revert(ptr, returndatasize())
            }
            returnSize := returndatasize()
            returnValue := mload(0)
        }

        if (returnSize == 0 ? address(token).code.length == 0 : returnValue != 1) {
            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 silently catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        bool success;
        uint256 returnSize;
        uint256 returnValue;
        assembly ("memory-safe") {
            success := call(gas(), token, 0, add(data, 0x20), mload(data), 0, 0x20)
            returnSize := returndatasize()
            returnValue := mload(0)
        }
        return success && (returnSize == 0 ? address(token).code.length > 0 : returnValue == 1);
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/IERC20.sol)

pragma solidity >=0.4.16;

/**
 * @dev Interface of the ERC-20 standard as defined in the ERC.
 */
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 v5.4.0) (interfaces/IERC20.sol)

pragma solidity >=0.4.16;

import {IERC20} from "../token/ERC20/IERC20.sol";
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/IERC165.sol)

pragma solidity >=0.4.16;

import {IERC165} from "../utils/introspection/IERC165.sol";
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/IERC1363.sol)

pragma solidity >=0.6.2;

import {IERC20} from "./IERC20.sol";
import {IERC165} from "./IERC165.sol";

/**
 * @title IERC1363
 * @dev Interface of the ERC-1363 standard as defined in the https://eips.ethereum.org/EIPS/eip-1363[ERC-1363].
 *
 * Defines an extension interface for ERC-20 tokens that supports executing code on a recipient contract
 * after `transfer` or `transferFrom`, or code on a spender contract after `approve`, in a single transaction.
 */
interface IERC1363 is IERC20, IERC165 {
    /*
     * Note: the ERC-165 identifier for this interface is 0xb0202a11.
     * 0xb0202a11 ===
     *   bytes4(keccak256('transferAndCall(address,uint256)')) ^
     *   bytes4(keccak256('transferAndCall(address,uint256,bytes)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256,bytes)')) ^
     *   bytes4(keccak256('approveAndCall(address,uint256)')) ^
     *   bytes4(keccak256('approveAndCall(address,uint256,bytes)'))
     */

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferAndCall(address to, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @param data Additional data with no specified format, sent in call to `to`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the allowance mechanism
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param from The address which you want to send tokens from.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferFromAndCall(address from, address to, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the allowance mechanism
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param from The address which you want to send tokens from.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @param data Additional data with no specified format, sent in call to `to`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferFromAndCall(address from, address to, uint256 value, bytes calldata data) external returns (bool);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens and then calls {IERC1363Spender-onApprovalReceived} on `spender`.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function approveAndCall(address spender, uint256 value) external returns (bool);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens and then calls {IERC1363Spender-onApprovalReceived} on `spender`.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     * @param data Additional data with no specified format, sent in call to `spender`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function approveAndCall(address spender, uint256 value, bytes calldata data) external returns (bool);
}
          

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

pragma solidity ^0.8.20;

import {Context} from "../utils/Context.sol";

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

    /**
     * @dev The caller account is not authorized to perform an operation.
     */
    error OwnableUnauthorizedAccount(address account);

    /**
     * @dev The owner is not a valid owner account. (eg. `address(0)`)
     */
    error OwnableInvalidOwner(address owner);

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

    /**
     * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
     */
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

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

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

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

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}