[ERC5496] NFTに紐づく特典の柔軟なやり取りの仕組みを理解しよう！

/// @title multi-privilege extension for EIP-721
///  Note: the EIP-165 identifier for this interface is 0x076e1bbb
interface IERC5496{
    /// @notice Emitted when `owner` changes the `privilege holder` of a NFT.
    event PrivilegeAssigned(uint256 tokenId, uint256 privilegeId, address user, uint256 expires);
    /// @notice Emitted when `contract owner` changes the `total privilege` of the collection
    event PrivilegeTotalChanged(uint256 newTotal, uint256 oldTotal);

    /// @notice set the privilege holder of a NFT.
    /// @dev expires should be less than 30 days
    /// Throws if `msg.sender` is not approved or owner of the tokenId.
    /// @param tokenId The NFT to set privilege for
    /// @param privilegeId The privilege to set
    /// @param user The privilege holder to set
    /// @param expires For how long the privilege holder can have
    function setPrivilege(uint256 tokenId, uint256 privilegeId, address user, uint256 expires) external;

    /// @notice Return the expiry timestamp of a privilege
    /// @param tokenId The identifier of the queried NFT
    /// @param privilegeId The identifier of the queried privilege
    /// @return Whether a user has a certain privilege
    function privilegeExpires(uint256 tokenId, uint256 privilegeId) external view returns(uint256);

    /// @notice Check if a user has a certain privilege
    /// @param tokenId The identifier of the queried NFT
    /// @param privilegeId The identifier of the queried privilege
    /// @param user The address of the queried user
    /// @return Whether a user has a certain privilege
    function hasPrivilege(uint256 tokenId, uint256 privilegeId, address user) external view returns(bool);
}

/// @title Cloneable extension - Optional for EIP-721
interface IERC721Cloneable {
    /// @notice Emitted when set the `privilege ` of a NFT cloneable.
    event PrivilegeCloned(uint tokenId, uint privId, address from, address to);

    /// @notice set a certain privilege cloneable
    /// @param tokenId The identifier of the queried NFT
    /// @param privilegeId The identifier of the queried privilege
    /// @param referrer The address of the referrer
    /// @return Whether the operation is successful or not
    function clonePrivilege(uint tokenId, uint privId, address referrer) external returns (bool);
}

// unwrap() 関数の定義
function unwrap(uint256 tokenId, address to) external {
    // 特権の最後の有効期限を過ぎていることを確認
    require(getBlockTimestamp() >= privilegeBook[tokenId].lastExpiresAt, "特権はまだ有効です");

    // トークンの所有者が呼び出し者であることを確認
    require(ownerOf(tokenId) == msg.sender, "所有者でないため操作できません");

    // トークンを燃やして（削除して）特権の取得を無効化
    _burn(tokenId);

    // NFTトークンを指定されたアドレスに移動
    IERC721(nft).transferFrom(address(this), to, tokenId);

    // Unwrapイベントを発行
    emit Unwrap(nft, tokenId, msg.sender, to);
}

// SPDX-License-Identifier: CC0-1.0
pragma solidity ^0.8.0; 

import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/utils/introspection/IERC165.sol";
import "./IERC5496.sol";

contract ERC5496 is ERC721, IERC5496 {
    struct PrivilegeRecord {
        address user;
        uint256 expiresAt;
    }
    struct PrivilegeStorage {
        uint lastExpiresAt;
        // privId => PrivilegeRecord
        mapping(uint => PrivilegeRecord) privilegeEntry;
    }

    uint public privilegeTotal;
    // tokenId => PrivilegeStorage
    mapping(uint => PrivilegeStorage) public privilegeBook;
    mapping(address => mapping(address => bool)) private privilegeDelegator;

    constructor(string memory name_, string memory symbol_)
    ERC721(name_,symbol_)
    {
    
    }

    function setPrivilege(
        uint tokenId,
        uint privId,
        address user,
        uint64 expires
    ) external virtual {
        require((hasPrivilege(tokenId, privId, ownerOf(tokenId)) && _isApprovedOrOwner(msg.sender, tokenId)) || _isDelegatorOrHolder(msg.sender, tokenId, privId), "ERC721: transfer caller is not owner nor approved");
        require(expires < block.timestamp + 30 days, "expire time invalid");
        require(privId < privilegeTotal, "invalid privilege id");
        privilegeBook[tokenId].privilegeEntry[privId].user = user;
        if (_isApprovedOrOwner(msg.sender, tokenId)) {
            privilegeBook[tokenId].privilegeEntry[privId].expiresAt = expires;
            if (privilegeBook[tokenId].lastExpiresAt < expires) {
                privilegeBook[tokenId].lastExpiresAt = expires;
            }
        }
        emit PrivilegeAssigned(tokenId, privId, user, uint64(privilegeBook[tokenId].privilegeEntry[privId].expiresAt));
    }

    function hasPrivilege(
        uint256 tokenId,
        uint256 privId,
        address user
    ) public virtual view returns(bool) {
        if (privilegeBook[tokenId].privilegeEntry[privId].expiresAt >= block.timestamp){
            return privilegeBook[tokenId].privilegeEntry[privId].user == user;
        }
        return ownerOf(tokenId) == user;
    }

    function privilegeExpires(
        uint256 tokenId,
        uint256 privId
    ) public virtual view returns(uint256){
        return privilegeBook[tokenId].privilegeEntry[privId].expiresAt;
    }

    function _setPrivilegeTotal(
        uint total
    ) internal {
        emit PrivilegeTotalChanged(total, privilegeTotal);
        privilegeTotal = total;
    }

    function getPrivilegeInfo(uint tokenId, uint privId) external view returns(address user, uint256 expiresAt) {
        return (privilegeBook[tokenId].privilegeEntry[privId].user, privilegeBook[tokenId].privilegeEntry[privId].expiresAt);
    }

    function setDelegator(address delegator, bool enabled) external {
        privilegeDelegator[msg.sender][delegator] = enabled;
    }

    function _isDelegatorOrHolder(address delegator, uint256 tokenId, uint privId) internal virtual view returns (bool) {
        address holder = privilegeBook[tokenId].privilegeEntry[privId].user;
         return (delegator == holder || isApprovedForAll(holder, delegator) || privilegeDelegator[holder][delegator]);
    }

    function supportsInterface(bytes4 interfaceId) public override virtual view returns (bool) {
        return interfaceId == type(IERC5496).interfaceId || super.supportsInterface(interfaceId);
    }
}

uint public privilegeTotal;

mapping(uint => PrivilegeStorage) public privilegeBook;

mapping(address => mapping(address => bool)) private privilegeDelegator;

struct PrivilegeStorage {
    uint lastExpiresAt;
    mapping(uint => PrivilegeRecord) privilegeEntry;
}

struct PrivilegeRecord {
    address user;
    uint256 expiresAt;
}

constructor(string memory name_, string memory symbol_)
    ERC721(name_, symbol_)
{
    
}

function setPrivilege(
        uint tokenId,
        uint privId,
        address user,
        uint64 expires
    ) external virtual {
        require((hasPrivilege(tokenId, privId, ownerOf(tokenId)) && _isApprovedOrOwner(msg.sender, tokenId)) || _isDelegatorOrHolder(msg.sender, tokenId, privId), "ERC721: transfer caller is not owner nor approved");
        require(expires < block.timestamp + 30 days, "expire time invalid");
        require(privId < privilegeTotal, "invalid privilege id");
        privilegeBook[tokenId].privilegeEntry[privId].user = user;
        if (_isApprovedOrOwner(msg.sender, tokenId)) {
            privilegeBook[tokenId].privilegeEntry[privId].expiresAt = expires;
            if (privilegeBook[tokenId].lastExpiresAt < expires) {
                privilegeBook[tokenId].lastExpiresAt = expires;
            }
        }
        emit PrivilegeAssigned(tokenId, privId, user, uint64(privilegeBook[tokenId].privilegeEntry[privId].expiresAt));
}

function hasPrivilege(
        uint256 tokenId,
        uint256 privId,
        address user
    ) public virtual view returns(bool) {
        if (privilegeBook[tokenId].privilegeEntry[privId].expiresAt >= block.timestamp){
            return privilegeBook[tokenId].privilegeEntry[privId].user == user;
        }
        return ownerOf(tokenId) == user;
}

function privilegeExpires(
        uint256 tokenId,
        uint256 privId
    ) public virtual view returns(uint256){
        return privilegeBook[tokenId].privilegeEntry[privId].expiresAt;
}

function _setPrivilegeTotal(
        uint total
    ) internal {
        emit PrivilegeTotalChanged(total, privilegeTotal);
        privilegeTotal = total;
}

function getPrivilegeInfo(uint tokenId, uint privId) external view returns(address user, uint256 expiresAt) {
        return (privilegeBook[tokenId].privilegeEntry[privId].user, privilegeBook[tokenId].privilegeEntry[privId].expiresAt);
}

function setDelegator(address delegator, bool enabled) external {
        privilegeDelegator[msg.sender][delegator] = enabled;
}

function _isDelegatorOrHolder(address delegator, uint256 tokenId, uint privId) internal virtual view returns (bool) {
        address holder = privilegeBook[tokenId].privilegeEntry[privId].user;
         return (delegator == holder || isApprovedForAll(holder, delegator) || privilegeDelegator[holder][delegator]);
}

function supportsInterface(bytes4 interfaceId) public override virtual view returns (bool) {
        return interfaceId == type(IERC5496).interfaceId || super.supportsInterface(interfaceId);
}