contract BTCRelay{
    function getLastBlockHeight() public returns(int256);
    function getBlockHash(int256) public returns(int256);

}

contract Powerball{
    mapping(address => uint8[6][]) public tickets;
    mapping(address => uint) public balances;
    uint public roundStart;
    uint public constant roundLength = 3 days;
    bool roundOver = false;
    enum Phase {Bet,Draw,Claim}
    Phase currentPhase = Phase.Bet;
    uint8[] public balls;
    BTCRelay relay;
    uint public constant houseEdge = 1; //percent of each ticket
    address house;
    uint houseFunds;
    int256 firstBlock;

    function Powerball(address relayAddress){
        relay = BTCRelay(relayAddress);
        roundStart = block.timestamp;
        house = msg.sender;
    }

    function buyTicket(uint8[6] numbers){
        if(startDraw()) throw;
        if(!checkNumbers(numbers)) throw;
        if(msg.value < 2 ether) throw;
        for(uint16 i = 0; i < msg.value/2; i++){
            tickets[msg.sender].push(numbers);
        }
        houseFunds += msg.value/100;
    }

    function startDraw() returns(bool){
        if(block.timestamp > roundStart + roundLength){
            if(currentPhase == Phase.Bet){
                currentPhase = Phase.Draw;
                firstBlock = relay.getLastBlockHeight() + 2;
            }
            return false;
        }
        return true;
    }

    function checkNumbers(uint8[6] numbers) returns (bool){
        for(var i = 0; i <6; i++){
            if (numbers[i] > 69 || numbers[i] <1) return false;
        }
        if(numbers[5]>26) return false;
        return true;
    }

    function getBall(uint8 ball) returns(uint8){
        if(balls[ball] != 0) return balls[ball];
        if(ball > 5) throw;
        if (relay.getLastBlockHeight() < 8+ball+firstBlock) throw;
        int256 hash  = relay.getBlockHash(firstBlock + ball);
        if (hash == 0) throw;
        else if(ball !=5) balls[ball] = uint8(hash) % 69 +1;
        else balls[ball] = uint8(hash)%26;
    }

}