// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/interfaces/IERC2981.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/introspection/IERC165.sol";

contract MyNFT is ERC721, Ownable, IERC2981 {
    using Strings for uint256;
    string private _base;
    address private _royaltyReceiver;
    uint96  private _royaltyBps; // 10000 = 100%

    constructor(string memory base_, address royaltyReceiver_, uint96 royaltyBps_)
        ERC721("MyNFT", "MNFT") Ownable(msg.sender)
    {
        _base = base_;
        _royaltyReceiver = royaltyReceiver_;
        _royaltyBps = royaltyBps_;
    }

    function _baseURI() internal view override returns (string memory) { return _base; }
    function setBase(string calldata b) external onlyOwner { _base = b; }

    function mint(address to, uint256 id) external onlyOwner { _safeMint(to, id); }

    // tokenURI: baseURI + tokenId + ".json"（IPFSで `1.json` のように保存しやすい形）
    function tokenURI(uint256 tokenId) public view override returns (string memory) {
        _requireOwned(tokenId);
        string memory base = _baseURI();
        if (bytes(base).length == 0) return "";
        string memory suffix = string.concat(tokenId.toString(), ".json");
        if (bytes(base)[bytes(base).length - 1] == bytes1("/")) return string.concat(base, suffix);
        return string.concat(base, "/", suffix);
    }

    // EIP‑2981
    function royaltyInfo(uint256, uint256 salePrice) external view override
        returns (address receiver, uint256 royaltyAmount)
    { return (_royaltyReceiver, (salePrice * _royaltyBps) / 10000); }

    // NOTE: IERC2981 は IERC165 準拠。ここでIFIDを認識し、その他は ERC721 実装へ委譲。
    function supportsInterface(bytes4 iid) public view override(ERC721, IERC165) returns (bool) {
        return iid == type(IERC2981).interfaceId || super.supportsInterface(iid);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;
// NOTE: DEMO ONLY / NOT FOR PRODUCTION
// 本契約は教材用の最小例。実運用不可の主な理由:
// - ReentrancyGuard/CEI等の再入防御なし
// - クリエイターロイヤリティ未対応（EIP-2981非連動）
// - キャンセル/有効期限/再出品の整合性なし
// - 手数料・スリッページ・会計処理の考慮なし
// 実運用時は監査済み実装と包括的テストを使用すること。
interface IERC721X { function safeTransferFrom(address,address,uint256) external; function ownerOf(uint256) external view returns(address); }
contract FixedPriceMarket {
    event Listed(address indexed nft, uint256 indexed id, address indexed seller, uint256 price);
    event Purchased(address indexed nft, uint256 indexed id, address indexed buyer, uint256 price);
    struct Listing { address seller; uint256 price; }
    mapping(address=>mapping(uint256=>Listing)) public listings;

    function list(address nft, uint256 id, uint256 price) external {
        require(IERC721X(nft).ownerOf(id) == msg.sender, "owner");
        require(price > 0, "price=0");
        require(listings[nft][id].seller == address(0), "already listed");
        listings[nft][id] = Listing(msg.sender, price);
        emit Listed(nft,id,msg.sender,price);
    }
    function buy(address nft, uint256 id) external payable {
        Listing memory L = listings[nft][id];
        require(L.seller != address(0), "no list");
        require(msg.value == L.price, "price");
        delete listings[nft][id];
        (bool ok,) = L.seller.call{value: msg.value}(""); require(ok, "pay");
        IERC721X(nft).safeTransferFrom(L.seller, msg.sender, id);
        emit Purchased(nft,id,msg.sender,msg.value);
    }
}