No-loss lottery where users deposit, earn yields, and win prizes without risking principal.

Prize Pool Contract

LotteryPoolV3 implements a no-loss lottery: deposit funds, earn yields, and have a chance to win prizes - all without risking your principal.

Contract Details

Features:

Deposit-based lottery (1 MUSD = 1 ticket)
Prizes funded by pool yields
No principal loss
Withdraw anytime
Regular draws
Random winner selection

How It Works

Users deposit MUSD (each MUSD = 1 ticket)
Pool earns yields from Mezo protocol
Weekly draw: 1 winner gets all yield
Users can withdraw principal anytime

State Variables

contract LotteryPoolV3 {
    mapping(address => uint256) public tickets;
    uint256 public totalTickets;
    uint256 public drawInterval; // 7 days
    uint256 public lastDrawTime;
    address public lastWinner;
    uint256 public lastPrize;
}

Read Functions

getTickets

function getTickets(address user) external view returns (uint256)

nextDrawTime

function nextDrawTime() external view returns (uint256)

estimatedPrize

function estimatedPrize() external view returns (uint256)

getWinProbability

function getWinProbability(address user) external view returns (uint256)

Returns probability in basis points (e.g., 500 = 5%)

Write Functions

deposit

Buy lottery tickets.

function deposit(uint256 amount) external nonReentrant

Example:

// Deposit 100 MUSD = 100 tickets
writeContract({
  address: LOTTERY_POOL_ADDRESS,
  abi: LOTTERY_POOL_ABI,
  functionName: 'deposit',
  args: [parseUnits('100', 18)]
})

withdraw

Withdraw principal (doesn't affect past drawings).

function withdraw(uint256 amount) external nonReentrant

executeDraw

Execute lottery draw (anyone can call if time passed).

function executeDraw() external nonReentrant returns (address winner, uint256 prize)

Events

event TicketsPurchased(address indexed user, uint256 amount, uint256 totalTickets);
event DrawExecuted(address indexed winner, uint256 prize, uint256 timestamp);
event PrizeWithdrawn(address indexed winner, uint256 amount);

Complete Example

function LotteryDashboard() {
  const { address } = useAccount()

  // User's tickets
  const { data: tickets } = useReadContract({
    address: LOTTERY_POOL_ADDRESS,
    abi: LOTTERY_POOL_ABI,
    functionName: 'getTickets',
    args: [address]
  })

  // Win probability
  const { data: probability } = useReadContract({
    address: LOTTERY_POOL_ADDRESS,
    abi: LOTTERY_POOL_ABI,
    functionName: 'getWinProbability',
    args: [address]
  })

  // Estimated prize
  const { data: prize } = useReadContract({
    address: LOTTERY_POOL_ADDRESS,
    abi: LOTTERY_POOL_ABI,
    functionName: 'estimatedPrize'
  })

  return (
    <div>
      <h2>Your Stats</h2>
      <p>Tickets: {tickets?.toString() || '0'}</p>
      <p>Win Probability: {(Number(probability || 0) / 100).toFixed(2)}%</p>
      <p>Current Prize Pool: {formatUnits(prize || 0n, 18)} MUSD</p>

      <button onClick={() => deposit('100')}>
        Buy 100 Tickets
      </button>
    </div>
  )
}

Prize Pool (Lottery) Contract