Lottery Contract

Contract roles:



injectorAddress (onlyInjector)

Injector is the address used to fund the lottery with periodic injections

operatorAddress (onlyOperator)

The lottery scheduler account used to run regular operations.

treasuryAddress (onlyTreasury)

The address in which the burn is sent

Owner (onlyOwner)

The contract owner



Address controlled by gnosis multisignature contract with a threshold of 3/6

Operator Address


Scheduler address - entirely automated and no human interaction. Not on multisig and doesn't have access to sensitive contract operations.

Treasury Address


Address controlled by gnosis multisignature contract with a threshold of 3/6

Injector Address (Currently the same as Owner)


Address controlled by gnosis multisignature contract with a threshold of 3/6


injectFunds - Injector and Owner

function injectFunds(uint256 _lotteryId, uint256 _amount) external override onlyOwnerOrInjector {
require(_lotteries[_lotteryId].status == Status.Open, "Lottery not open");
cakeToken.safeTransferFrom(address(msg.sender), address(this), _amount);
_lotteries[_lotteryId].amountCollectedInCake += _amount;
emit LotteryInjection(_lotteryId, _amount);

The Injector or Owner can call this function to inject a specific lotteryId with a specified amount of CAKE.

startLottery - Operator

function startLottery(
uint256 _endTime,
uint256 _priceTicketInCake,
uint256 _discountDivisor,
uint256[6] calldata _rewardsBreakdown,
uint256 _treasuryFee
) external override onlyOperator {
(currentLotteryId == 0) || (_lotteries[currentLotteryId].status == Status.Claimable),
"Not time to start lottery"
((_endTime - block.timestamp) > MIN_LENGTH_LOTTERY) && ((_endTime - block.timestamp) < MAX_LENGTH_LOTTERY),
"Lottery length outside of range"
(_priceTicketInCake >= minPriceTicketInCake) && (_priceTicketInCake <= maxPriceTicketInCake),
"Outside of limits"
require(_discountDivisor >= MIN_DISCOUNT_DIVISOR, "Discount divisor too low");
require(_treasuryFee <= MAX_TREASURY_FEE, "Treasury fee too high");
(_rewardsBreakdown[0] +
_rewardsBreakdown[1] +
_rewardsBreakdown[2] +
_rewardsBreakdown[3] +
_rewardsBreakdown[4] +
_rewardsBreakdown[5]) == 10000,
"Rewards must equal 10000"
_lotteries[currentLotteryId] = Lottery({
status: Status.Open,
startTime: block.timestamp,
endTime: _endTime,
priceTicketInCake: _priceTicketInCake,
discountDivisor: _discountDivisor,
rewardsBreakdown: _rewardsBreakdown,
treasuryFee: _treasuryFee,
cakePerBracket: [uint256(0), uint256(0), uint256(0), uint256(0), uint256(0), uint256(0)],
countWinnersPerBracket: [uint256(0), uint256(0), uint256(0), uint256(0), uint256(0), uint256(0)],
firstTicketId: currentTicketId,
firstTicketIdNextLottery: currentTicketId,
amountCollectedInCake: pendingInjectionNextLottery,
finalNumber: 0
emit LotteryOpen(
pendingInjectionNextLottery = 0;

The startLottery function is only callable by the Operator in order to start a new lottery round.

closeLottery - Operator

function closeLottery(uint256 _lotteryId) external override onlyOperator nonReentrant {
require(_lotteries[_lotteryId].status == Status.Open, "Lottery not open");
require(block.timestamp > _lotteries[_lotteryId].endTime, "Lottery not over");
_lotteries[_lotteryId].firstTicketIdNextLottery = currentTicketId;
// Request a random number from the generator based on a seed
randomGenerator.getRandomNumber(uint256(keccak256(abi.encodePacked(_lotteryId, currentTicketId))));
_lotteries[_lotteryId].status = Status.Close;
emit LotteryClose(_lotteryId, currentTicketId);

Callable by the Operator to close a round of the lottery.

drawFinalNumberAndMakeLotteryClaimable - Operator

function drawFinalNumberAndMakeLotteryClaimable(uint256 _lotteryId, bool _autoInjection)
require(_lotteries[_lotteryId].status == Status.Close, "Lottery not close");
require(_lotteryId == randomGenerator.viewLatestLotteryId(), "Numbers not drawn");
// Calculate the finalNumber based on the randomResult generated by ChainLink's fallback
uint32 finalNumber = randomGenerator.viewRandomResult();
// Initialize a number to count addresses in the previous bracket
uint256 numberAddressesInPreviousBracket;
// Calculate the amount to share post-treasury fee
uint256 amountToShareToWinners = (
((_lotteries[_lotteryId].amountCollectedInCake) * (10000 - _lotteries[_lotteryId].treasuryFee))
) / 10000;
// Initializes the amount to withdraw to treasury
uint256 amountToWithdrawToTreasury;
// Calculate prizes in CAKE for each bracket by starting from the highest one
for (uint32 i = 0; i < 6; i++) {
uint32 j = 5 - i;
uint32 transformedWinningNumber = _bracketCalculator[j] + (finalNumber % (uint32(10)**(j + 1)));
_lotteries[_lotteryId].countWinnersPerBracket[j] =
_numberTicketsPerLotteryId[_lotteryId][transformedWinningNumber] -
// A. If number of users for this _bracket number is superior to 0
if (
(_numberTicketsPerLotteryId[_lotteryId][transformedWinningNumber] - numberAddressesInPreviousBracket) !=
) {
// B. If rewards at this bracket are > 0, calculate, else, report the numberAddresses from previous bracket
if (_lotteries[_lotteryId].rewardsBreakdown[j] != 0) {
_lotteries[_lotteryId].cakePerBracket[j] =
((_lotteries[_lotteryId].rewardsBreakdown[j] * amountToShareToWinners) /
(_numberTicketsPerLotteryId[_lotteryId][transformedWinningNumber] -
numberAddressesInPreviousBracket)) /
// Update numberAddressesInPreviousBracket
numberAddressesInPreviousBracket = _numberTicketsPerLotteryId[_lotteryId][transformedWinningNumber];
// A. No CAKE to distribute, they are added to the amount to withdraw to treasury address
} else {
_lotteries[_lotteryId].cakePerBracket[j] = 0;
amountToWithdrawToTreasury +=
(_lotteries[_lotteryId].rewardsBreakdown[j] * amountToShareToWinners) /
// Update internal statuses for lottery
_lotteries[_lotteryId].finalNumber = finalNumber;
_lotteries[_lotteryId].status = Status.Claimable;
if (_autoInjection) {
pendingInjectionNextLottery = amountToWithdrawToTreasury;
amountToWithdrawToTreasury = 0;
amountToWithdrawToTreasury += (_lotteries[_lotteryId].amountCollectedInCake - amountToShareToWinners);
// Transfer CAKE to treasury address
cakeToken.safeTransfer(treasuryAddress, amountToWithdrawToTreasury);
emit LotteryNumberDrawn(currentLotteryId, finalNumber, numberAddressesInPreviousBracket);

For Operator to draw the final number using ChainLink VRF function.

recoverWrongTokens - Owner

function recoverWrongTokens(address _tokenAddress, uint256 _tokenAmount) external onlyOwner {
require(_tokenAddress != address(cakeToken), "Cannot be CAKE token");
IERC20(_tokenAddress).safeTransfer(address(msg.sender), _tokenAmount);
emit AdminTokenRecovery(_tokenAddress, _tokenAmount);

In the case of tokens other than CAKE mistakenly being sent to the lottery contract, this function is used to recover them and is only callable by the Owner

setMinAndMaxTicketPriceInCake - Owner

function setMinAndMaxTicketPriceInCake(uint256 _minPriceTicketInCake, uint256 _maxPriceTicketInCake)
require(_minPriceTicketInCake <= _maxPriceTicketInCake, "minPrice must be < maxPrice");
minPriceTicketInCake = _minPriceTicketInCake;
maxPriceTicketInCake = _maxPriceTicketInCake;

To prevent the Operator setting the tickets to arbitrary prices during the event of a flash crash/pump.

setMaxNumberTicketsPerBuy - Owner

function setMaxNumberTicketsPerBuy(uint256 _maxNumberTicketsPerBuy) external onlyOwner {
require(_maxNumberTicketsPerBuy != 0, "Must be > 0");
maxNumberTicketsPerBuyOrClaim = _maxNumberTicketsPerBuy;

The Owner can modify the maximum number of tickets per transaction. This may be modified in the case of BSC block size increasing or decreasing.

setOperatorAndTreasuryAndInjectorAddresses - Owner

function setOperatorAndTreasuryAndInjectorAddresses(
address _operatorAddress,
address _treasuryAddress,
address _injectorAddress
) external onlyOwner {
require(_operatorAddress != address(0), "Cannot be zero address");
require(_treasuryAddress != address(0), "Cannot be zero address");
require(_injectorAddress != address(0), "Cannot be zero address");
operatorAddress = _operatorAddress;
treasuryAddress = _treasuryAddress;
injectorAddress = _injectorAddress;
emit NewOperatorAndTreasuryAndInjectorAddresses(_operatorAddress, _treasuryAddress, _injectorAddress);

Function used to set the Operator, Treasury, and Injector addresses.

changeRandomGenerator - Owner

function changeRandomGenerator(address _randomGeneratorAddress) external onlyOwner {
(currentLotteryId == 0) || (_lotteries[currentLotteryId].status == Status.Claimable),
"Lottery not in claimable"
// Request a random number from the generator based on a seed
uint256(keccak256(abi.encodePacked(currentLotteryId, currentTicketId)))
// Calculate the finalNumber based on the randomResult generated by ChainLink's fallback
randomGenerator = IRandomNumberGenerator(_randomGeneratorAddress);
emit NewRandomGenerator(_randomGeneratorAddress);

For the Owner to update the RandomNumberGenerator contract in case we need to update the drawing logic, or release an update.