NSeoulTowerMarket 스마트컨트랙트

NSeoulTowerMarket.sol

contract NSeoulTowerMarket {

    address private _LoveChainAddress;
    address private _deployer;

    uint256 private constant NFT_NUMBERS = 500;
    
    constructor(address LoveChainAddress) public {
        _LoveChainAddress = LoveChainAddress;
        _deployer = msg.sender;
    }

    mapping (uint256 => address) public seller;
    mapping (uint256 => uint256) public price;

    function buyLoveChain(uint256 tokenId) public payable returns (bool) {
        address payable receiver = address(uint256(seller[tokenId]));
        uint256 _price = price[tokenId];

        receiver.transfer(_price * (10 ** 13)); // 저장된 가격 * 1KLAY (현재는 테스트로 0.00001 KLAY로 설정)
        LoveChain(_LoveChainAddress).safeTransferFrom(address(this), msg.sender, tokenId, _uint256toBytes(_price)); // data로 거래 가격을 전송
        _clearSeller(tokenId);
        _clearPrice(tokenId);

        return true;
    }

    function _clearSeller(uint256 tokenId) private { // 거래 완료 시 seller 정보 삭제
        delete seller[tokenId];
    }

    function _clearPrice(uint256 tokenId) private { // 거래 완료 시 price 정보 삭제
        delete price[tokenId];
    }

    function _bytestoUint256(bytes memory _bytes) internal pure returns (uint256 value) { // 타입캐스팅
        assembly {
            value := mload(add(_bytes, 0x20))
        }
    }

    function _uint256toBytes(uint256 _uint256) internal pure returns (bytes memory value) { // 타입캐스팅
        value = new bytes(32);
        assembly { 
            mstore(add(value, 32), _uint256) 
        }
    }

    function setMintedToken(uint256 tokenId, uint256 _price) public { // 마켓으로 민팅할 때 price를 설정하기 위한 함수
        require(msg.sender == _LoveChainAddress, "you are not LoveChain");
        seller[tokenId] = _deployer;
        price[tokenId] = _price;
    }

    function onKIP17Received(address operator, address from, uint256 tokenId, bytes memory data) public returns (bytes4) {
        require(tokenId <= NFT_NUMBERS, "This token is not placed in NSeoulTower"); // 마켓이 받은 NFT가 남산타워의 것이 맞는지?
        seller[tokenId] = from; // 판매자 주소 등록
        price[tokenId] = _bytestoUint256(data); // data로 받아온 price 저장

        return bytes4(keccak256("onKIP17Received(address,address,uint256,bytes)"));
    }
}