made changes in the smart contract

contract/Integration.js

@@ -0,0 +1,30 @@
+const Web3 = Noderequire('web3');
+const PaymentNFTContract = Noderequire('<path-to-contract-abi>');
+const contractAddress = '<address-of-contract>';
+const web3 = new Web3('<rpc-endpoint>');
+
+// Instantiate the contract object
+const paymentNFTContract = new web3.eth.Contract(PaymentNFTContract.abi, contractAddress);
+
+// Add event listener for payment confirmation
+document.getElementById('payment-button').addEventListener('click', async () => {
+  const paymentAmount = // Get payment amount from user input
+  const accounts = await web3.eth.getAccounts();
+  await paymentNFTContract.methods.pay().send({from: accounts[0], value: paymentAmount});
+  // Notify the user that payment was successful
+});
+
+// Add event listener for NFT purchase
+document.getElementById('nft-purchase-button').addEventListener('click', async () => {
+  const accounts = await web3.eth.getAccounts();
+  await paymentNFTContract.methods.purchaseNFT().send({from: accounts[0]});
+  // Notify the user that the NFT was purchased and transferred to their wallet
+});
+
+/* 
+The payment-button and nft-purchase-button elements are assumed to be present in the HTML page, and event listeners are added to handle payment and NFT purchase actions.
+
+When the payment button is clicked, the pay() function is called on the contract with the payment amount and sender's account address. Once the transaction is confirmed, the user is notified that the payment was successful.
+
+When the NFT purchase button is clicked, the purchaseNFT() function is called on the contract with the sender's account address. Once the transaction is confirmed, the user is notified that the NFT was purchased and transferred to their wallet
+*/

contract/Payment.sol

@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: MIT
+pragma solidity ^0.8.0;
+
+import "@openzeppelin/contracts/token/ERC721/ERC721.sol";
+import "@openzeppelin/contracts/utils/Counters.sol";
+
+ contract Payment is ERC721{
+    using Counters for Counters.Counter;
+    Counters.Counter private _tokenIds;
+
+    address payable public owner;
+    mapping(address => uint256) public balances;
+
+    constructor(string memory name, string memory symbol) ERC721(name, symbol){
+        owner = payable(msg.sender);
+    }
+
+    function pay() public payable {
+        balances[msg.sender] += msg.value;
+    }
+
+    function purchaseNFT() public{
+        require(balances[msg.sender] >0, "INSUFFICIENT BALANCE");
+        _tokenIds.increment();
+        uint newItemId = _tokenIds.current();
+        _mint(msg.sender, newItemId);
+        balances[msg.sender] = 0;
+    }
+}