11 、迷恋猫的交易

 // 处理猫的拍卖，之前的拍卖合约，是可以处理所有的ERC721合约的，
 // 这里是把猫
contract KittyAuction is KittyBreeding {

   

    /// 设置买卖交易所的地址 ，只有ceo才能执行
    /// @param _address - 合约地址
    function setSaleAuctionAddress(address _address) external onlyCEO {
        // 实例化合约
        SaleClockAuction candidateContract = SaleClockAuction(_address);

        // 验证是否是买卖的合约
        require(candidateContract.isSaleClockAuction());

        // 设置新的买卖交易所，saleAuction是在KittyBase中
        saleAuction = candidateContract;
    }

    /// 设置新的交配交易所
    /// @param _address - 交配交易所地址
    function setSiringAuctionAddress(address _address) external onlyCEO {
        SiringClockAuction candidateContract = SiringClockAuction(_address);

        require(candidateContract.isSiringClockAuction());

        // 设置新的交配交易所，siringAuction是在KittyBase中
        siringAuction = candidateContract;
    }

    ///创建一个新的买卖的拍卖，外部调用
    ///  Does some ownership trickery to create auctions in one tx.
    function createSaleAuction(
        uint256 _kittyId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration
    )
        external
        whenNotPaused
    {
        // 权限判断，合约的调用者必须是代币的拥有者
        require(_owns(msg.sender, _kittyId));
        // 判断是否怀孕
        require(!isPregnant(_kittyId));
        // 授权saleAuction 可以拍买 _kittyId
        _approve(_kittyId, saleAuction);
        // 调用买卖交易所的createAuction方法，创建拍卖
        //  msg.sender 为本合约地址
        saleAuction.createAuction(
            _kittyId,
            _startingPrice,
            _endingPrice,
            _duration,
            msg.sender
        );
    }

    ///  创建新的交配的拍卖，外部调用
    function createSiringAuction(
        uint256 _kittyId,
        uint256 _startingPrice,
        uint256 _endingPrice,
        uint256 _duration
    )
        external
        whenNotPaused
    {
        // 权限判断，所有者
        require(_owns(msg.sender, _kittyId));
        // 冻结时间是否结束
        require(isReadyToBreed(_kittyId));
        // 授权给了 拍卖所
        _approve(_kittyId, siringAuction);
        // 交配交易所，创建交配
        siringAuction.createAuction(
            _kittyId,
            _startingPrice,
            _endingPrice,
            _duration,
            msg.sender
        );
    }

    /// 完成交配的拍卖
    function bidOnSiringAuction(
        uint256 _sireId,
        uint256 _matronId
    )
        external
        payable
        whenNotPaused
    {
        // 所有权
        require(_owns(msg.sender, _matronId));
        // 插件冻结期
        require(isReadyToBreed(_matronId));
        // 是否可以交易所拍卖
        require(_canBreedWithViaAuction(_matronId, _sireId));

        // 获取当前价格
        uint256 currentPrice = siringAuction.getCurrentPrice(_sireId);
      // 判断当前价格 是否 大于 怀孕费用
        require(msg.value >= currentPrice + autoBirthFee);

        // value(msg.value - autoBirthFee) 合约与合约之间，转移多余的以太币
        siringAuction.bid.value(msg.value - autoBirthFee)(_sireId);
        // 繁殖交配成功
        _breedWith(uint32(_matronId), uint32(_sireId));
    }

    /// 转账，将拍卖所中的以太币转走，只有管理员才能操作
    function withdrawAuctionBalances() external onlyCLevel {
        saleAuction.withdrawBalance();
        siringAuction.withdrawBalance();
    }
}