lottery contract, tests and demo script

contracts/lottery.sol

@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import {zkdvrf} from "./zkdvrf.sol";
+
+import "@openzeppelin/contracts/utils/Strings.sol";
+import '@openzeppelin/contracts/access/Ownable.sol';
+
+contract Lottery is Ownable {
+    using Strings for uint256;
+
+    address payable[] public players;
+    mapping(address => bool) public hasEntered;
+    uint256 public minBet;
+
+    address public zkdvrfAddr;
+    uint256 public randRoundNum;
+    bytes32 public randValue;
+
+    enum Status {
+        Setup,
+        Open,
+        Close
+    }
+
+    Status public contractPhase;
+
+    event BetOpen(uint256 randRoundNumber, uint256 minBetAmount);
+
+    constructor(address zkdvrfAddress) Ownable(msg.sender) {
+        zkdvrfAddr = zkdvrfAddress;
+    }
+
+    function setup(uint256 randRoundNumber, uint256 minBetAmount) public onlyOwner {
+        require(contractPhase == Status.Setup, "Setup has already been completed");
+        randRoundNum = randRoundNumber;
+        minBet = minBetAmount;
+
+        contractPhase = Status.Open;
+        emit BetOpen(randRoundNumber, minBetAmount);
+    }
+
+    // check if random has been produced or is being produced
+    function roundReached() public returns (bool) {
+        uint256 latestRoundNum = zkdvrf(zkdvrfAddr).currentRoundNum();
+        return randRoundNum <= latestRoundNum;
+    }
+
+    function enter() public payable {
+        require(contractPhase == Status.Open, "Not open yet");
+        // Once the random generation starts or has completed, players are no longer allowed to enter
+        require(!roundReached(), "Too late. Random has been produced or is being produced");
+        require(!hasEntered[msg.sender], "You have already entered the lottery");
+        require(msg.value >= minBet, "Must provide enough bet");
+
+        players.push(payable(msg.sender));
+        hasEntered[msg.sender] = true;
+    }
+
+    // Fisher-Yates Shuffle
+    function shuffle() private {
+        require(randValue != 0x00, "Random not ready yet");
+
+        for (uint i = 0; i < players.length; i++) {
+            bytes32 randomBytes = keccak256(abi.encodePacked(randValue, i));
+            uint256 random = uint256(randomBytes);
+
+            uint j = random % (i + 1);
+            (players[i], players[j]) = (players[j], players[i]);
+        }
+    }
+
+    function pickWinner() public onlyOwner {
+        require(contractPhase == Status.Open, "Not open");
+        require(players.length > 0, "No players");
+        // read random from zkdvrf contract
+        randValue = zkdvrf(zkdvrfAddr).getRandomAtRound(randRoundNum).value;
+        shuffle(); // Shuffle the players array
+        // The winner is the first player in the shuffled array
+        // The permutation is randomly generated so we can also take more winners if needed
+        (bool success, ) = players[0].call{value: address(this).balance}("");
+        require(success, "Transfer failed.");
+
+        contractPhase = Status.Close;
+    }
+
+
+    function getPlayers() public view returns (address payable[] memory) {
+        return players;
+    }
+}

demo-config.json

@@ -13,5 +13,12 @@
     "0x742e271d909d026b2b4dcc0384ec0b8df8f674f0773c354b57c24858419e89d3",
     "0xeeb82181766c7d0fe45d2cb5b3399b1da17a1a432938ec8c4d73daca85eedaea",
     "0x88b68d7e8d96d8465cfe3dc4abf707e21aa49139189a784e2d50cc9ada9076c3"
+  ],
+  "lotteryAddress": "0x019254975A0e82C44e16CCEd295e332C1F6774f2",
+  "lotteryAdminKey": "0xc9224470c28153019fb65b231370e8c946b65b9d012e46e57d6f9f3f7827e5cd",
+  "lotteryPlayerKeys": [
+    "0xa8a4ba3252cdf977c2d16a67f8eefae5d26e88637a23b6c82b4dbb2364eb7fb5",
+    "0x7fa41fbee14d382f42df346fe92cbde2fcb3bbd30fbfffb505c5466a62bc5d77",
+    "0x3fc3e099ad4811fa4b8c7f2c2d796337de84b5e8ec34817015d7f4c1ac92efef"
   ]
 }

package.json

@@ -34,7 +34,10 @@
     "register": "npx hardhat run scripts/register.ts",
     "nidkg": "npx hardhat run scripts/nidkg.ts",
     "member": "yarn register && yarn nidkg",
-    "random": "npx hardhat run scripts/random.ts"
+    "random": "npx hardhat run scripts/random.ts",
+    "lottery:deploy": "npx hardhat run scripts/lottery/deploy.ts",
+    "lottery:admin": "npx hardhat run scripts/lottery/admin.ts",
+    "lottery:play": "npx hardhat run scripts/lottery/play.ts"
   },
   "repository": {
     "type": "git",

scripts/lottery/admin.ts

@@ -0,0 +1,76 @@
+import hre, {artifacts, ethers} from "hardhat";
+import {Contract, ContractFactory, providers, utils, Wallet} from "ethers";
+import {readJsonFromFile} from "../utils";
+
+const config = readJsonFromFile("demo-config.json")
+const zkdvrfAddress = config.zkdvrfAddress
+const lotteryAddress = config.lotteryAddress
+const adminKey = config.lotteryAdminKey
+
+async function main() {
+    const netprovider = new providers.JsonRpcProvider(process.env.RPC_URL)
+    const adminWallet = new Wallet(adminKey, netprovider)
+
+    const Lottery = await ethers.getContractFactory('Lottery')
+    const contractABI = Lottery.interface.format();
+    const contract = new ethers.Contract(lotteryAddress, contractABI, netprovider).connect(adminWallet)
+
+    const randRoundNumber = 3
+    const minBet = ethers.utils.parseEther("5");
+    const res = await contract.setup(randRoundNumber, minBet)
+    const receipt = await netprovider.getTransactionReceipt(res.hash);
+    // Check if the transaction was successful
+    if (receipt.status === 1) {
+        console.log(`Transaction setup(..) successful!`);
+    } else {
+        console.error(`Transaction setup(..) failed!`);
+    }
+    console.log("Bet starts")
+    console.log("Waiting for random in round ", randRoundNumber)
+
+    const Zkdvrf = await ethers.getContractFactory('zkdvrf')
+    const zkContractABI = Zkdvrf.interface.format();
+    const zkContract = new ethers.Contract(zkdvrfAddress, zkContractABI, netprovider)
+
+    // This will run when the event is emitted
+    const eventName = `RandomReady`
+    zkContract.on(eventName, async (roundNum, input, event) => {
+        console.log("event", eventName, roundNum, input);
+        // Proceed to the next step here
+        if (roundNum == randRoundNumber) {
+            // the random number is ready
+            const res = await contract.pickWinner()
+            // Check if the transaction was successful
+            const receipt = await netprovider.getTransactionReceipt(res.hash);
+            if (receipt.status === 1) {
+                console.log("Transaction pickWinner() successful!");
+            } else {
+                console.error("Transaction pickWinner() failed!");
+            }
+
+            const status = await contract.contractPhase()
+            console.log("Lottery contract status:", status)
+
+            const players = await contract.getPlayers()
+            console.log("Players:", players)
+
+            // query users balance
+            for (let i = 0; i < players.length; i++) {
+                netprovider.getBalance(players[i]).then((balance) => {
+                    // Convert Wei to Ether
+                    let etherString = ethers.utils.formatEther(balance);
+                    console.log(players[i], " balance: " + etherString);
+                }).catch((err) => {
+                    console.error(err);
+                });
+            }
+        }
+    });
+
+}
+
+
+main().catch((error) => {
+    console.error(error);
+    process.exitCode = 1;
+});

scripts/lottery/deploy.ts

@@ -0,0 +1,26 @@
+import hre, {artifacts, ethers} from "hardhat";
+import {Contract, ContractFactory, providers, utils, Wallet} from "ethers";
+import {readJsonFromFile} from "../utils";
+
+const config = readJsonFromFile("demo-config.json")
+const zkdvrfAddress = config.zkdvrfAddress
+const adminKey = config.lotteryAdminKey
+
+async function main() {
+  const netprovider = new providers.JsonRpcProvider(process.env.RPC_URL)
+  const deployerWallet = new Wallet(adminKey, netprovider)
+
+  const Lottery = await ethers.getContractFactory('Lottery')
+  const lottery = await Lottery.connect(deployerWallet).deploy(zkdvrfAddress)
+  await lottery.deployed()
+
+  console.log("Lottery contract deployed at", lottery.address)
+}
+
+main().then(() => {
+  process.exit(0);
+})
+.catch((error) => {
+  console.error(error);
+  process.exitCode = 1;
+});

scripts/lottery/play.ts

@@ -0,0 +1,46 @@
+import hre, {artifacts, ethers} from "hardhat";
+import {providers, Wallet} from "ethers";
+import {readJsonFromFile} from "../utils";
+
+const config = readJsonFromFile("demo-config.json")
+const lotteryAddress = config.lotteryAddress
+const playerKeys = config.lotteryPlayerKeys
+
+
+async function main() {
+    const netprovider = new providers.JsonRpcProvider(process.env.RPC_URL)
+
+    const Lottery = await ethers.getContractFactory('Lottery')
+    const contractABI = Lottery.interface.format();
+    const contract = new ethers.Contract(lotteryAddress, contractABI, netprovider);
+
+    // This will run when the event is emitted
+    const eventName = `BetOpen`
+    contract.on(eventName, async (randRoundNum, minBet, event) => {
+        console.log("event", eventName, randRoundNum, minBet);
+        // Proceed to the next step here
+
+        for (let i = 0; i < playerKeys.length; i++) {
+            const userWallet = new Wallet(playerKeys[i], netprovider)
+            const userAddress = userWallet.address
+            const userContract = contract.connect(userWallet)
+
+            try {
+                let tx = await userContract.enter({
+                    value: minBet,
+                    from: userAddress,
+                });
+                console.log(tx);
+            } catch (err) {
+                console.error(err);
+            }
+        }
+
+        process.exit(0);
+    });
+}
+
+main().catch((error) => {
+    console.error(error);
+    process.exitCode = 1;
+});