Initial commit with 🏗️ create-eth @ 2.0.4

packages/hardhat/scripts/fetchPriceFromUniswap.ts

@@ -0,0 +1,68 @@
+import { ethers } from "hardhat";
+import * as dotenv from "dotenv";
+dotenv.config();
+
+import { config as hardhatConfig } from "hardhat";
+import { getConfig, updatePriceCache } from "./utils";
+import { parseEther, formatEther } from "ethers";
+
+const UNISWAP_V2_PAIR_ABI = [
+  "function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast)",
+  "function token0() external view returns (address)",
+  "function token1() external view returns (address)",
+];
+
+const DAI_ADDRESS = "0x6B175474E89094C44Da98b954EedeAC495271d0F";
+const WETH_ADDRESS = "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2";
+const UNISWAP_V2_FACTORY = "0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f";
+const mainnet = hardhatConfig.networks.mainnet;
+const MAINNET_RPC = "url" in mainnet ? mainnet.url : "";
+
+export const fetchPriceFromUniswap = async (): Promise<bigint> => {
+  const config = getConfig();
+  const cachedPrice = config.PRICE.CACHEDPRICE;
+  const timestamp = config.PRICE.TIMESTAMP;
+
+  if (Date.now() - timestamp < 1000 * 60 * 60) {
+    return parseEther(cachedPrice.toString());
+  }
+  console.log("Cache expired or missing, fetching fresh price from Uniswap...");
+
+  try {
+    const provider = new ethers.JsonRpcProvider(MAINNET_RPC);
+    const tokenAddress = WETH_ADDRESS; // Always use WETH for mainnet
+
+    // Get pair address from Uniswap V2 Factory
+    const factory = new ethers.Contract(
+      UNISWAP_V2_FACTORY,
+      ["function getPair(address tokenA, address tokenB) external view returns (address pair)"],
+      provider,
+    );
+
+    const pairAddress = await factory.getPair(tokenAddress, DAI_ADDRESS);
+    if (pairAddress === ethers.ZeroAddress) {
+      throw new Error("No liquidity pair found");
+    }
+
+    const pairContract = new ethers.Contract(pairAddress, UNISWAP_V2_PAIR_ABI, provider);
+    const [reserves, token0Address] = await Promise.all([pairContract.getReserves(), pairContract.token0()]);
+
+    // Determine which reserve is token and which is DAI
+    const isToken0 = token0Address.toLowerCase() === tokenAddress.toLowerCase();
+    const tokenReserve = isToken0 ? reserves[0] : reserves[1];
+    const daiReserve = isToken0 ? reserves[1] : reserves[0];
+
+    // Calculate price (DAI per token)
+    const price = BigInt(Math.floor((Number(daiReserve) / Number(tokenReserve)) * 1e18));
+
+    // Update cache with fresh price
+    const pricePerEther = parseFloat(formatEther(price));
+    updatePriceCache(pricePerEther, Date.now());
+    console.log(`Fresh price fetched and cached: ${formatEther(price)} ETH`);
+
+    return price;
+  } catch (error) {
+    console.error("Error fetching ETH price from Uniswap: ", error);
+    return parseEther(cachedPrice.toString());
+  }
+};