version 1

.gitignore

@@ -45,3 +45,4 @@ typechain
 #Hardhat files
 cache
 artifacts
+

contracts/Comments.sol

@@ -0,0 +1,36 @@
+//SPDX-License-Identifier: Unlicense
+pragma solidity ^0.8.0;
+
+import "hardhat/console.sol";
+
+contract Comments {
+    struct Comment {
+        uint32 id;
+        string topic;
+        address creator_address;
+        string message;
+        uint created_at;
+    }
+
+    uint32 private idCounter;
+    mapping(string => Comment[]) private commentsByTopic;
+
+    event CommentAdded(Comment comment);
+
+    function getComments(string calldata topic) public view returns(Comment[] memory) {
+       return commentsByTopic[topic];
+    }
+
+    function addComment(string calldata topic, string calldata message) public {
+        Comment memory comment = Comment({
+            id: idCounter,
+            topic: topic,
+            creator_address: msg.sender,
+            message: message,
+            created_at: block.timestamp
+        });
+        commentsByTopic[topic].push(comment);
+        idCounter++;
+        emit CommentAdded(comment);
+    }
+}

hardhat.config.js

@@ -0,0 +1,21 @@
+require("@nomiclabs/hardhat-waffle");
+
+// This is a sample Hardhat task. To learn how to create your own go to
+// https://hardhat.org/guides/create-task.html
+task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
+  const accounts = await hre.ethers.getSigners();
+
+  for (const account of accounts) {
+    console.log(account.address);
+  }
+});
+
+// You need to export an object to set up your config
+// Go to https://hardhat.org/config/ to learn more
+
+/**
+ * @type import('hardhat/config').HardhatUserConfig
+ */
+module.exports = {
+  solidity: "0.8.4",
+};

pages/index.tsx

@@ -4,6 +4,28 @@ import { QueryClient, QueryClientProvider } from "react-query";
 import { ChakraProvider, Box, Heading } from "@chakra-ui/react";
 import { Toaster } from "react-hot-toast";
 import theme from "../theme";
+import { Provider as WagmiProvider, InjectedConnector, chain } from "wagmi";
+import { providers } from "ethers";
+
+// Chains for connectors to support
+const chains = [chain.polygonTestnetMumbai, chain.hardhat];
+
+// Provide a fallback network while chainId is not yet defined
+const provider = ({ chainId, connector }) => {
+  const selectedChain = connector?.chains.find((c) => c.id === chainId);
+  return providers.getDefaultProvider(
+    selectedChain?.rpcUrls?.[0] || "http://localhost:8545"
+  );
+};
+
+// Enables sign-in with Metamask
+const connectors = () => {
+  return [
+    new InjectedConnector({
+      chains,
+    }),
+  ];
+};
 
 // Create a client
 const queryClient = new QueryClient({
@@ -16,14 +38,16 @@ const queryClient = new QueryClient({
 
 const App: NextPage = () => {
   return (
-    <ChakraProvider theme={theme}>
-      <QueryClientProvider client={queryClient}>
-        <Box p={8} maxW="600px" minW="320px" m="0 auto">
-          <Heading>Oops, no comments yet!</Heading>
-          <Toaster position="bottom-right" />
-        </Box>
-      </QueryClientProvider>
-    </ChakraProvider>
+    <WagmiProvider autoConnect provider={provider} connectors={connectors}>
+      <ChakraProvider theme={theme}>
+        <QueryClientProvider client={queryClient}>
+          <Box p={8} maxW="600px" minW="320px" m="0 auto">
+            <Heading>Oops, no comments yet!</Heading>
+            <Toaster position="bottom-right" />
+          </Box>
+        </QueryClientProvider>
+      </ChakraProvider>
+    </WagmiProvider>
   );
 };
 

scripts/deploy-and-seed.js

@@ -0,0 +1,38 @@
+// We require the Hardhat Runtime Environment explicitly here. This is optional
+// but useful for running the script in a standalone fashion through `node <script>`.
+//
+// When running the script with `npx hardhat run <script>` you'll find the Hardhat
+// Runtime Environment's members available in the global scope.
+const hre = require("hardhat");
+
+async function main() {
+  // Hardhat always runs the compile task when running scripts with its command
+  // line interface.
+  //
+  // If this script is run directly using `node` you may want to call compile
+  // manually to make sure everything is compiled
+  // await hre.run('compile');
+
+  // We get the contract to deploy
+  const CommentsContract = await hre.ethers.getContractFactory("Comments");
+  const contract = await CommentsContract.deploy();
+
+  await contract.deployed();
+
+  const tx1 = await contract.addComment("my-blog-post", "My first comment");
+  await tx1.wait();
+
+  const tx2 = await contract.addComment("my-blog-post", "My second comment");
+  await tx2.wait();
+
+  console.log("Contract deployed to:", contract.address);
+}
+
+// We recommend this pattern to be able to use async/await everywhere
+// and properly handle errors.
+main()
+  .then(() => process.exit(0))
+  .catch((error) => {
+    console.error(error);
+    process.exit(1);
+  });

test/basic.js

@@ -0,0 +1,30 @@
+const { expect } = require("chai");
+const { ethers } = require("hardhat");
+
+describe("Comments", function () {
+  it("Should add and fetch successfully", async function () {
+    const Comments = await ethers.getContractFactory("Comments");
+    const comments = await Comments.deploy();
+    await comments.deployed();
+
+    expect(await comments.getComments("my-first-blog-post")).to.be.lengthOf(0);
+
+    const tx1 = await comments.addComment(
+      "my-first-blog-post",
+      "my first comment"
+    );
+    await tx1.wait();
+
+    expect(await comments.getComments("my-first-blog-post")).to.be.lengthOf(1);
+    expect(await comments.getComments("my-second-blog-post")).to.be.lengthOf(0);
+
+    const tx2 = await comments.addComment(
+      "my-second-blog-post",
+      "this comment is on a different thread"
+    );
+    await tx2.wait();
+
+    expect(await comments.getComments("my-first-blog-post")).to.be.lengthOf(1);
+    expect(await comments.getComments("my-second-blog-post")).to.be.lengthOf(1);
+  });
+});