add mock contracts and start work on price feed page

packages/hardhat/contracts/PriceFeedConsumer.sol

@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.7;
+
+// Import the AggregatorV3Interface from the "@chainlink/contracts" package
+import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";
+
+
+/**
+ * 
+ * 
+ */
+
+contract PriceFeedConsumer {
+    // Declare state variable of type AggregatorV3Interface
+    AggregatorV3Interface internal immutable i_priceFeed;
+
+    // Create a constructor that accepts the address of the price feed as an argument
+    constructor(address priceFeedAddress) {
+        i_priceFeed = AggregatorV3Interface(priceFeedAddress);
+    }
+
+    // Create a function to get the latest price
+    function getLatestPrice() public view returns (int) {
+        (, int price, , , ) = i_priceFeed.latestRoundData();
+        return price;
+    }
+}

packages/hardhat/contracts/mocks/MockV3Aggregator.sol

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import "@chainlink/contracts/src/v0.8/tests/MockV3Aggregator.sol";
+
+
+/**
+ * @dev Mock contract implementation of AggregatorV3Interface
+ * allows for testing and debugging on local network
+ */

packages/hardhat/contracts/mocks/VRFCoordinatorV2Mock.sol

@@ -0,0 +1,5 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.7;
+
+import "@chainlink/contracts/src/v0.8/mocks/VRFCoordinatorV2Mock.sol";

packages/hardhat/deploy/00_mocks.ts

@@ -0,0 +1,50 @@
+import { HardhatRuntimeEnvironment } from "hardhat/types";
+import { DeployFunction } from "hardhat-deploy/types";
+import { developmentChains } from "../helper-hardhat-config";
+import { network } from "hardhat";
+
+/**
+ * Deploys mock contracts necessary for testing on local networks
+ *
+ * @param hre HardhatRuntimeEnvironment object.
+ */
+
+const deployMocks: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
+  const { deployer } = await hre.getNamedAccounts();
+  const { deploy, log } = hre.deployments;
+  const { ethers } = hre;
+
+  // MockV3Aggregator constructor arguments
+  const INTIIAL_PRICE = ethers.utils.parseUnits("1579", 8); // sets MockV3Aggregator.latestRoundData().answer
+  const DECIMALS = "8";
+
+  // Chainlink VRF Coordinator constructor arguments
+  const BASE_FEE = ethers.utils.parseEther("0.25"); // 0.25 is the premium. It costs 0.25 LINK per request
+  const GAS_PRICE_LINK = 1e9; // calculated value based on the gas price of the chain
+
+  if (developmentChains.includes(network.name)) {
+    log("Local network detected... Deploying mocks...");
+
+    log("Deploying MockV3Aggregator...");
+    await deploy("MockV3Aggregator", {
+      from: deployer,
+      log: true,
+      args: [DECIMALS, INTIIAL_PRICE],
+    });
+
+    log("Deploying VRFCoordinatorV2Mock...");
+    await deploy("VRFCoordinatorV2Mock", {
+      from: deployer,
+      log: true,
+      args: [BASE_FEE, GAS_PRICE_LINK],
+    });
+    log("Mock contracts successfully deployed on local network!");
+    log("------------------------------------");
+  }
+};
+
+export default deployMocks;
+
+// Tags are useful if you have multiple deploy files and only want to run one of them.
+// e.g. yarn deploy --tags YourContract
+deployMocks.tags = ["all", "mocks"];

packages/hardhat/deploy/01_PriceFeedConsumer.ts

@@ -0,0 +1,45 @@
+import { HardhatRuntimeEnvironment } from "hardhat/types";
+import { DeployFunction } from "hardhat-deploy/types";
+import { developmentChains, networkConfig } from "../helper-hardhat-config";
+import { network } from "hardhat";
+
+/**
+ * Deploy PriceFeedConsumer contract
+ *
+ * @param hre HardhatRuntimeEnvironment object.
+ */
+const deployPriceFeedConsumer: DeployFunction = async function (hre: HardhatRuntimeEnvironment) {
+  const { deployer } = await hre.getNamedAccounts();
+  const { deploy, log } = hre.deployments;
+  const { ethers } = hre;
+
+  //   const chainId = network.config.chainId;
+  const chainId = await hre.ethers.provider.getNetwork().then(network => network.chainId);
+  console.log(`The current chain ID is: ${chainId}`);
+
+  log("------------------------------------");
+  let priceFeedAddress: string | undefined;
+
+  if (developmentChains.includes(network.name)) {
+    // use mock address if on local network
+    const MockV3Aggregator = await ethers.getContract("MockV3Aggregator");
+    priceFeedAddress = MockV3Aggregator.address;
+  } else {
+    // use address from helper-hardhat-config if on testnet or live network
+    priceFeedAddress = networkConfig[chainId].priceFeeds?.ETH_USD;
+  }
+
+  const args = [priceFeedAddress];
+  await deploy("PriceFeedConsumer", {
+    from: deployer,
+    args: args,
+    log: true,
+    autoMine: true,
+  });
+
+  // * HOW TO VERIFY : https://docs.scaffoldeth.io/deploying/deploy-smart-contracts#4-verify-your-smart-contract
+};
+
+export default deployPriceFeedConsumer;
+
+deployPriceFeedConsumer.tags = ["price-consumer", "all"];

packages/hardhat/hardhat.config.ts

@@ -17,14 +17,18 @@ const etherscanApiKey = process.env.ETHERSCAN_API_KEY || "DNXJA8RX2Q3VZ4URQIWP7Z
 
 const config: HardhatUserConfig = {
   solidity: {
-    version: "0.8.17",
-    settings: {
-      optimizer: {
-        enabled: true,
-        // https://docs.soliditylang.org/en/latest/using-the-compiler.html#optimizer-options
-        runs: 200,
+    compilers: [
+      {
+        version: "0.8.17",
+        settings: {
+          optimizer: {
+            enabled: true,
+            // https://docs.soliditylang.org/en/latest/using-the-compiler.html#optimizer-options
+            runs: 200,
+          },
+        },
       },
-    },
+    ],
   },
   defaultNetwork: "localhost",
   namedAccounts: {

packages/hardhat/helper-hardhat-config.ts

@@ -0,0 +1,42 @@
+interface NetworkConfigEntryTypes {
+  name?: string;
+  vrfCoordinatorV2?: string;
+  subscriptionId?: string;
+  gasLane?: string;
+  callbackGasLimit?: string;
+  interval?: string;
+  mintFee?: string;
+  priceFeeds?: {
+    BTC_USD: string;
+    ETH_USD: string;
+    LINK_USD: string;
+  };
+}
+
+const networkConfig: { [key: number]: NetworkConfigEntryTypes } = {
+  31337: {
+    name: "hardhat",
+    gasLane: "0x474e34a077df58807dbe9c96d3c009b23b3c6d0cce433e59bbf5b34f823bc56c",
+    interval: "30",
+    callbackGasLimit: "500000", // 500,000 gas
+    mintFee: "100000000000000000", // 0.1 ETH
+  },
+  11155111: {
+    name: "sepolia",
+    vrfCoordinatorV2: "0x8103B0A8A00be2DDC778e6e7eaa21791Cd364625",
+    subscriptionId: "4707", // vrf.chain.link/sepolia/4707
+    gasLane: "0x474e34a077df58807dbe9c96d3c009b23b3c6d0cce433e59bbf5b34f823bc56c",
+    callbackGasLimit: "500000", // 500,000
+    interval: "30",
+    mintFee: "100000000000000000", // 0.1 ETH
+    priceFeeds: {
+      BTC_USD: "0x1b44F3514812d835EB1BDB0acB33d3fA3351Ee43",
+      ETH_USD: "0x694AA1769357215DE4FAC081bf1f309aDC325306",
+      LINK_USD: "0xc59E3633BAAC79493d908e63626716e204A45EdF",
+    },
+  },
+};
+
+const developmentChains: string[] = ["hardhat", "localhost"];
+
+export { networkConfig, developmentChains };

packages/hardhat/package.json

@@ -46,6 +46,7 @@
     "typescript": "^5.1.6"
   },
   "dependencies": {
+    "@chainlink/contracts": "^0.7.1",
     "@openzeppelin/contracts": "^4.8.1",
     "dotenv": "^16.0.3",
     "envfile": "^6.18.0",

packages/nextjs/components/ExternalLink.tsx

@@ -0,0 +1,14 @@
+import { ArrowTopRightOnSquareIcon } from "@heroicons/react/24/outline";
+
+interface ExternalLinkProps {
+  href: string;
+  text: string;
+}
+
+export const ExternalLink: React.FC<ExternalLinkProps> = ({ href, text }) => {
+  return (
+    <a href={href} className="capitalize text-accent hover:underline" target="_blank" rel="noopener noreferrer">
+      {text} <ArrowTopRightOnSquareIcon className="h-5 w-5 inline mb-1" />
+    </a>
+  );
+};

packages/nextjs/components/Header.tsx

@@ -37,7 +37,7 @@ export const Header = () => {
   const navLinks = (
     <>
       <li>
-        <NavLink href="/data-feeds">📈 Data Feeds</NavLink>
+        <NavLink href="/data-feeds">📈 Price Feeds</NavLink>
       </li>
       <li>
         <NavLink href="/automation">🤖 Automation</NavLink>