Week 4

.gitignore

@@ -0,0 +1,4 @@
+node_modules
+.env
+artifacts
+cache

contracts/MyNFT.sol

@@ -1,26 +1,29 @@
-// Contract based on https://docs.openzeppelin.com/contracts/4.x/erc721
 // SPDX-License-Identifier: MIT
-pragma solidity ^0.8.0;
+pragma solidity ^0.8.20;  // Using latest stable Solidity version
 
 import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
-import "@openzeppelin/contracts/utils/Counters.sol";
+import "@openzeppelin/contracts/access/Ownable.sol";
 
-contract MyNFT is ERC721URIStorage {
-    using Counters for Counters.Counter;
-    Counters.Counter private _tokenIds;
+contract MyNFT is ERC721URIStorage, Ownable {
+    uint256 private _nextTokenId;
 
-    constructor() ERC721("MyNFT", "MNFT") {}
+    constructor() 
+        ERC721("MyNFT", "MNFT")
+        Ownable(msg.sender)  // Explicitly set the owner
+    {}
 
     function mintNFT(address recipient, string memory tokenURI)
-    public
-    returns (uint256)
+        public
+        returns (uint256)
     {
-        _tokenIds.increment();
-
-        uint256 newItemId = _tokenIds.current();
-        _mint(recipient, newItemId);
-        _setTokenURI(newItemId, tokenURI);
+        uint256 tokenId = _nextTokenId++; 
+        _safeMint(recipient, tokenId);     // Using safeMint instead of _mint
+        _setTokenURI(tokenId, tokenURI);
+
+        return tokenId;
+    }
 
-        return newItemId;
+    function getNextTokenId() public view returns (uint256) {
+        return _nextTokenId;
     }
-}
+}

hardhat.config.ts

@@ -1,24 +1,40 @@
-import("@nomiclabs/hardhat-ethers");
-import("@nomiclabs/hardhat-waffle");
-import dotenv from "dotenv";
-
-const argv = JSON.parse(env("npm_config_argv"));
-if (argv.original !== ["hardhat", "test"]) {
-  require('dotenv').config();
-}
+import { HardhatUserConfig } from "hardhat/config";
+import "@nomiclabs/hardhat-ethers";
+import "@nomiclabs/hardhat-waffle";
+import * as dotenv from "dotenv";
 
-import("./tasks/nft");
+// Load environment variables
+dotenv.config();
 
-import { HardhatUserConfig } from "hardhat/config";
+// Import tasks
+import "./tasks/nft";
 
 const config: HardhatUserConfig = {
-  solidity: "0.8.0",
+  solidity: {
+    version: "0.8.20",
+    settings: {
+      optimizer: {
+        enabled: true,
+        runs: 200
+      }
+    }
+  },
   networks: {
+    hardhat: {},
     sepolia: {
       url: `https://eth-sepolia.alchemyapi.io/v2/${process.env.ALCHEMY_API_KEY}`,
-      accounts: [process.env.ETH_PRIVATE_KEY],
-    },
+      accounts: process.env.ETH_PRIVATE_KEY ? [process.env.ETH_PRIVATE_KEY] : [],
+    }
+  },
+  paths: {
+    sources: "./contracts",
+    tests: "./test",
+    cache: "./cache",
+    artifacts: "./artifacts"
   },
+  mocha: {
+    timeout: 40000
+  }
 };
 
-export default config;
+export default config;

lib/contract.ts

@@ -1,13 +1,12 @@
-import { Contract, ethers } from "ethers";
-import { getContractAt } from "@nomiclabs/hardhat-ethers/internal/helpers";
-import { HardhatRuntimeEnvironment } from "hardhat/types";
-import { env } from "./env";
-import { getProvider } from "./provider";
+import { ethers } from 'ethers';
+import { getWallet } from './wallet';
+import * as MyNFT from '../artifacts/contracts/MyNFT.sol/MyNFT.json';
 
-export function getContract(
-  name: string,
-  hre: HardhatRuntimeEnvironment
-): Promise<Contract> {
-  const WALLET = new ethers.Wallet(env("ETH_PRIVATE_KEY"), getProvider());
-  return getContractAt(hre, name, env("NFT_CONTRACT_ADDRESS"), WALLET);
+export async function getContract(contractAddress: string): Promise<ethers.Contract> {
+    const wallet = getWallet();
+    return new ethers.Contract(
+        contractAddress,
+        MyNFT.abi,
+        wallet
+    );
 }

lib/env.ts

@@ -1,7 +1,10 @@
-export function env(key: string): string {
+import * as dotenv from 'dotenv';
+dotenv.config();
+
+export function getEnvVar(key: string): string {
     const value = process.env[key];
-    if (value === undefined) {
-      throw `${key} is undefined`;
+    if (!value) {
+        throw new Error(`Environment variable ${key} is not set`);
     }
     return value;
-  }  
+}

lib/provider.ts

@@ -1,7 +1,9 @@
-import { ethers } from "ethers";
+import { ethers } from 'ethers';
+import { getEnvVar } from './env';
 
-export function getProvider(): ethers.providers.Provider {
-  return ethers.getDefaultProvider("ropsten", {
-    alchemy: process.env.ALCHEMY_API_KEY,
-  });
+export function getProvider(): ethers.providers.AlchemyProvider {
+    return new ethers.providers.AlchemyProvider(
+        'sepolia',
+        getEnvVar('ALCHEMY_API_KEY')
+    );
 }

lib/wallet.ts

@@ -1,7 +1,10 @@
-import { ethers } from "ethers";
-import { env } from "./env";
-import { getProvider } from "./provider";
+import { ethers } from 'ethers';
+import { getEnvVar } from './env';
+import { getProvider } from './provider';
 
 export function getWallet(): ethers.Wallet {
-  return new ethers.Wallet(env("ETH_PRIVATE_KEY"), getProvider());
+    return new ethers.Wallet(
+        getEnvVar('ETH_PRIVATE_KEY'),
+        getProvider()
+    );
 }