Y12 Simple Open Auction 3

ysoa3.sol

// Solidity by Example — Solidity 0.2.0 documentation  http://solidity.readthedocs.org/en/latest/solidity-by-example.html
// Ethereum以太坊智能合約環境說明 https://gist.github.com/y12studio/f142cd9789c7d396d8f7
contract YSOA {
    // time periods in seconds.
    address public beneficiary;
    address public feeDao;
    uint public auctionStart;
    uint public biddingTime;
    uint32 public feePpm;
    uint8 public luckPercent;
    uint public feeBalance;

    // Current state of the auction.
    address public highestBidder;
    uint public highestBid;

    // Set to true at the end, disallows any change
    bool ended;

    // Events that will be fired on changes.
    event HighestBidIncreased(address bidder, uint amount);
    event AuctionEnded(address winner, uint amount);

    // Create a simple auction with `_biddingTime`
    // seconds bidding time on behalf of the
    // beneficiary address `_beneficiary`.
    // feeDao address 
    // feeRate parts per million(PPM), 0.256% = 2560 ppm
    // 
    function YSOA(uint _biddingTime, address _beneficiary, address _feeDao, uint32 _feePpm, uint8 _luckPercent) {
        beneficiary = _beneficiary;
        feeDao = _feeDao;
        feePpm = _feePpm;
        auctionStart = now;
        biddingTime = _biddingTime;
        luckPercent = _luckPercent;
    }

    /// Bid on the auction with the value sent
    /// together with this transaction.
    /// The value will only be refunded if the
    /// auction is not won.
    function bid() {
        // No arguments are necessary, all
        // information is already part of
        // the transaction.
        if (now > auctionStart + biddingTime)
            // Revert the call if the bidding
            // period is over.
            throw;
        if (msg.value <= highestBid)
            // If the bid is not higher, send the
            // money back.
            throw;
        if (highestBidder != 0) {
              uint ran = randomGen(feeBalance);
              uint fee = highestBid/1000000*feePpm;
              if(ran<luckPercent){
                  fee = 0;
              }
              feeBalance += fee;
              highestBidder.send(highestBid-fee);
            }
        highestBidder = msg.sender;
        highestBid = msg.value;
        HighestBidIncreased(msg.sender, msg.value);
    }

    // End the auction and send the highest bid to the beneficiary.
    function auctionEnd() {
        if (now <= auctionStart + biddingTime)
            throw; // auction did not yet end
        if (ended)
            throw; // this function has already been called
        AuctionEnded(highestBidder, highestBid);
        uint benAmount = this.balance-feeBalance;
        if(feeBalance>0){
            feeDao.send(feeBalance);
        }
        beneficiary.send(benAmount);
        ended = true;
    }
    
    function rescueBalanceDevOnly(){
        beneficiary.send(this.balance);
    }
    
    //  ref to https://gist.github.com/alexvandesande/259b4ffb581493ec0a1c
    //  Generates a random number from 0 to 100 based on the last block hash
    function randomGen(uint seed) constant returns(uint randomNumber) {
        return (uint(sha3(block.blockhash(block.number - 1), seed)) % 100);
    }

    function () {
        throw;
    }
}