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Exercise 2: Build Your First Cross-Chain NFT

Coding Time 🎉

CCIP Config Details

Arbitrum Sepolia

Ethereum Sepolia

Chain Selector

Getting started

You can use Chainlink CCIP with any blockchain development framework. For this Masterclass, we prepared the steps for Hardhat, Foundry, and Remix IDE.

Let's create a new project

Make sure you have and installed. To check, run the following command:

Create a new folder and name it ccip-masterclass-3

Navigate to it

Create a hew Hardhat project by running:

And then select "Create a TypeScript project".

Make sure you have installed. To check, run the following command:

Alternatively, you can clone:

The @chainlink/contracts-ccip NPM package

To use Chainlink CCIP, you need to interact with Chainlink CCIP-specific contracts from the NPM package.

To install it, follow steps specific to the development environment you will use for this Masterclass.

We will need a standard NPM package for this Module as well, so let's install it too while we are here by running the following command:

Finally, for this exercise we will need to install and the NPM package, as well. To do so, run:

Since Foundry is designed to run with Solidity, NPM packages, though usable, ,can be replaced with directly installying Solidity contract packages from Github source repositories. We will install Chainlink CCIP contracts and then the contracts for other Chainlink Services.

First the CCIP Contracts.

And after that set remappings in your foundry.toml

Faucet

To pay for CCIP Fees you can use either LINK token or native/wrapped native asset on a given blockchain. For this exercise we will need at least 1 LINK or Arbitrum Sepolia testnet. To get it, navigate to the

Develop xNFT smart contract

Create a new file inside the contracts folder and name it XNFT.sol

Compile your contract by running:

Create a new file inside the src folder and name it XNFT.sol

Create a new Solidity file by clicking on the "Create new file" button and name it XNFT.sol

Prepare for deployment

Follow the steps to add the necessary environment variables for deploying these contracts and sending your first CCIP Message.

This contract expects at least 0.8.20 Solidity version. It is very important to understand that with Solc version 0.8.20, the default EVM version is set to "Shanghai". A new opcode, PUSH0, was added to the Ethereum Virtual Machine in the Shanghai upgrade.

However, besides Ethereum, the majority of blockchains haven't included PUSH0 opcode.

That means the PUSH0 opcode can now be part of the contract's bytecode and if the chain you are working on does not support it, it will error with the "Invalid opcode" error.

To understand more, we highly encourage you to check this StackOverflow answer:

We are going to use the package for extra security. It encrypts sensitive data instead of storing them as plain text in the .env file by creating a new .env.enc file. Although it's not recommended to push this file online, if that accidentally happens, your secrets will still be encrypted.

Install the package by running the following command:

Set a password for encrypting and decrypting the environment variable file. You can change it later by typing the same command.

Now set the following environment variables: PRIVATE_KEY, Source Blockchain RPC URL, Destination Blockchain RPC URL. For this example, we are going to use Arbitrum Sepolia and Ethereum Sepolia.

To set these variables, type the following command and follow the instructions in the terminal:

Step 1) Deploy XNFT.sol to Ethereum Sepolia

Prepare Chain Selector and CCIP Router & LINK token addresses on Ethereum Sepolia. You can get them if you scroll to the beginning of this page, at

Navigate to the scripts folder and create new file named deployXNFT.ts

Run the deployment script:

Prepare Chain Selector and CCIP Router & LINK token addresses on Ethereum Sepolia. You can get them if you scroll to begging of this page, at

Option 1)

Step 2) Deploy XNFT.sol to Arbitrum Sepolia

Prepare Chain Selector and CCIP Router & LINK token addresses on Arbitrum Sepolia. You can get them if you scroll to beginning of this page, at

Navigate to the scripts folder and create new file named deployXNFTArbitrum.ts

Run the deployment script:

Prepare Chain Selector and CCIP Router & LINK token addresses on Arbitrum Sepolia. You can get them if you scroll to begging of this page, at

Option 1)

Step 3) On Ethereum Sepolia, call enableChain function

Prepare:

The address of the address of the XNFT.sol smart contract you previously deployed to Ethereum Sepolia;
The address of the address of the XNFT.sol smart contract you previously deployed to Arbitrum Sepolia;

Step 4) On Arbitrum Sepolia, call enableChain function

Prepare:

The address of the XNFT.sol smart contract you previously deployed to Arbitrum Sepolia;
The address of the address of the XNFT.sol smart contract you previously deployed to Ethereum Sepolia, as xNftAddress parameter;

Step 5) On Arbitrum Sepolia, fund XNFT.sol with 3 LINK

To cover for CCIP fees, fund XNFT.sol with some amount of LINK, 3 should be more than enough for this demo. Obviously, for the sake of full functionality, you should fund XNFT.sol smart contract on other blockchains as well, so you can perform cross-chain transfers between all of them.

Step 6) On Arbitrum Sepolia, mint new xNFT

Create a new TypeScript file under the scripts folder and name it mint.ts

Call the function by running the following command:

Run:

Under the "Deployed Contracts" section, you should find the XNFT.sol contract you previously deployed to Arbitrum Sepolia. Find the mint function and hit the "Transact" orange button.

Step 7) On Arbitrum Sepolia, crossTransferFrom xNFT

Prepare:

Your EOA address, as the from parameter;
The address of an EOA on other chain where you want to cross-transfer your NFT, can be your EOA address, as to parameter;

You can now monitor this cross-chain transfer on CCIP Explorer page.

Once cross-chain NFT arrives to Ethereum Sepolia, you can manually display it inside your Metamask wallet. Navigate to the "NFT" tab and hit the "Import NFT" button.

Then, fill in XNFT.sol smart contract address on Ethereum Sepolia and token ID you received (0).

Finally, your NFT will appear inside Metamask wallet.

Exercise 2: Build Your First Cross-Chain NFT

Coding Time 🎉

CCIP Config Details

Arbitrum Sepolia

Ethereum Sepolia

Chain Selector

Getting started

You can use Chainlink CCIP with any blockchain development framework. For this Masterclass, we prepared the steps for Hardhat, Foundry, and Remix IDE.

Let's create a new project

Make sure you have and installed. To check, run the following command:

Create a new folder and name it ccip-masterclass-3

Navigate to it

Create a hew Hardhat project by running:

And then select "Create a TypeScript project".

Make sure you have installed. To check, run the following command:

Alternatively, you can clone:

The @chainlink/contracts-ccip NPM package

To use Chainlink CCIP, you need to interact with Chainlink CCIP-specific contracts from the NPM package.

To install it, follow steps specific to the development environment you will use for this Masterclass.

We will need a standard NPM package for this Module as well, so let's install it too while we are here by running the following command:

Finally, for this exercise we will need to install and the NPM package, as well. To do so, run:

First the CCIP Contracts.

And after that set remappings in your foundry.toml

Faucet

Develop xNFT smart contract

Create a new file inside the contracts folder and name it XNFT.sol

Compile your contract by running:

Create a new file inside the src folder and name it XNFT.sol

Create a new Solidity file by clicking on the "Create new file" button and name it XNFT.sol

Prepare for deployment

Follow the steps to add the necessary environment variables for deploying these contracts and sending your first CCIP Message.

However, besides Ethereum, the majority of blockchains haven't included PUSH0 opcode.

That means the PUSH0 opcode can now be part of the contract's bytecode and if the chain you are working on does not support it, it will error with the "Invalid opcode" error.

To understand more, we highly encourage you to check this StackOverflow answer:

Install the package by running the following command:

Set a password for encrypting and decrypting the environment variable file. You can change it later by typing the same command.

Now set the following environment variables: PRIVATE_KEY, Source Blockchain RPC URL, Destination Blockchain RPC URL. For this example, we are going to use Arbitrum Sepolia and Ethereum Sepolia.

To set these variables, type the following command and follow the instructions in the terminal:

Step 1) Deploy XNFT.sol to Ethereum Sepolia

Prepare Chain Selector and CCIP Router & LINK token addresses on Ethereum Sepolia. You can get them if you scroll to the beginning of this page, at

Navigate to the scripts folder and create new file named deployXNFT.ts

Run the deployment script:

Prepare Chain Selector and CCIP Router & LINK token addresses on Ethereum Sepolia. You can get them if you scroll to begging of this page, at

Option 1)

Step 2) Deploy XNFT.sol to Arbitrum Sepolia

Prepare Chain Selector and CCIP Router & LINK token addresses on Arbitrum Sepolia. You can get them if you scroll to beginning of this page, at

Navigate to the scripts folder and create new file named deployXNFTArbitrum.ts

Run the deployment script:

Prepare Chain Selector and CCIP Router & LINK token addresses on Arbitrum Sepolia. You can get them if you scroll to begging of this page, at

Option 1)

Step 3) On Ethereum Sepolia, call enableChain function

Prepare:

The address of the address of the XNFT.sol smart contract you previously deployed to Ethereum Sepolia;
The address of the address of the XNFT.sol smart contract you previously deployed to Arbitrum Sepolia;

Step 4) On Arbitrum Sepolia, call enableChain function

Prepare:

The address of the XNFT.sol smart contract you previously deployed to Arbitrum Sepolia;
The address of the address of the XNFT.sol smart contract you previously deployed to Ethereum Sepolia, as xNftAddress parameter;

Step 5) On Arbitrum Sepolia, fund XNFT.sol with 3 LINK

Step 6) On Arbitrum Sepolia, mint new xNFT

Create a new TypeScript file under the scripts folder and name it mint.ts

Call the function by running the following command:

Run:

Under the "Deployed Contracts" section, you should find the XNFT.sol contract you previously deployed to Arbitrum Sepolia. Find the mint function and hit the "Transact" orange button.

Step 7) On Arbitrum Sepolia, crossTransferFrom xNFT

Prepare:

Your EOA address, as the from parameter;
The address of an EOA on other chain where you want to cross-transfer your NFT, can be your EOA address, as to parameter;

You can now monitor this cross-chain transfer on CCIP Explorer page.

Once cross-chain NFT arrives to Ethereum Sepolia, you can manually display it inside your Metamask wallet. Navigate to the "NFT" tab and hit the "Import NFT" button.

Then, fill in XNFT.sol smart contract address on Ethereum Sepolia and token ID you received (0).

Finally, your NFT will appear inside Metamask wallet.

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import {ERC721URIStorage} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import {ERC721Burnable} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import {IERC20} from "@openzeppelin/contracts/interfaces/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import {Client} from "@chainlink/contracts-ccip/src/v0.8/ccip/libraries/Client.sol";
import {IRouterClient} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IRouterClient.sol";
import {IAny2EVMMessageReceiver} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IAny2EVMMessageReceiver.sol";
import {OwnerIsCreator} from "@chainlink/contracts-ccip/src/v0.8/shared/access/OwnerIsCreator.sol";
import {LinkTokenInterface} from "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";

/**
 * THIS IS AN EXAMPLE CONTRACT THAT USES HARDCODED VALUES FOR CLARITY.
 * THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE.
 * DO NOT USE THIS CODE IN PRODUCTION.
 */
contract XNFT is
    ERC721,
    ERC721URIStorage,
    ERC721Burnable,
    IAny2EVMMessageReceiver,
    ReentrancyGuard,
    OwnerIsCreator
{
    using SafeERC20 for IERC20;

    enum PayFeesIn {
        Native,
        LINK
    }

    error InvalidRouter(address router);
    error OnlyOnArbitrumSepolia();
    error NotEnoughBalanceForFees(
        uint256 currentBalance,
        uint256 calculatedFees
    );
    error NothingToWithdraw();
    error FailedToWithdrawEth(address owner, address target, uint256 value);
    error ChainNotEnabled(uint64 chainSelector);
    error SenderNotEnabled(address sender);
    error OperationNotAllowedOnCurrentChain(uint64 chainSelector);

    struct XNftDetails {
        address xNftAddress;
        bytes ccipExtraArgsBytes;
    }

    uint256 constant ARBITRUM_SEPOLIA_CHAIN_ID = 421614;

    string[] characters = [
        "https://ipfs.io/ipfs/QmTgqnhFBMkfT9s8PHKcdXBn1f5bG3Q5hmBaR4U6hoTvb1?filename=Chainlink_Elf.png",
        "https://ipfs.io/ipfs/QmZGQA92ri1jfzSu61JRaNQXYg1bLuM7p8YT83DzFA2KLH?filename=Chainlink_Knight.png",
        "https://ipfs.io/ipfs/QmW1toapYs7M29rzLXTENn3pbvwe8ioikX1PwzACzjfdHP?filename=Chainlink_Orc.png",
        "https://ipfs.io/ipfs/QmPMwQtFpEdKrUjpQJfoTeZS1aVSeuJT6Mof7uV29AcUpF?filename=Chainlink_Witch.png"
    ];

    IRouterClient internal immutable i_ccipRouter;
    LinkTokenInterface internal immutable i_linkToken;
    uint64 private immutable i_currentChainSelector;

    uint256 private _nextTokenId;

    mapping(uint64 destChainSelector => XNftDetails xNftDetailsPerChain)
        public s_chains;

    event ChainEnabled(
        uint64 chainSelector,
        address xNftAddress,
        bytes ccipExtraArgs
    );
    event ChainDisabled(uint64 chainSelector);
    event CrossChainSent(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );
    event CrossChainReceived(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );

    modifier onlyRouter() {
        if (msg.sender != address(i_ccipRouter))
            revert InvalidRouter(msg.sender);
        _;
    }

    modifier onlyOnArbitrumSepolia() {
        if (block.chainid != ARBITRUM_SEPOLIA_CHAIN_ID)
            revert OnlyOnArbitrumSepolia();
        _;
    }

    modifier onlyEnabledChain(uint64 _chainSelector) {
        if (s_chains[_chainSelector].xNftAddress == address(0))
            revert ChainNotEnabled(_chainSelector);
        _;
    }

    modifier onlyEnabledSender(uint64 _chainSelector, address _sender) {
        if (s_chains[_chainSelector].xNftAddress != _sender)
            revert SenderNotEnabled(_sender);
        _;
    }

    modifier onlyOtherChains(uint64 _chainSelector) {
        if (_chainSelector == i_currentChainSelector)
            revert OperationNotAllowedOnCurrentChain(_chainSelector);
        _;
    }

    constructor(
        address ccipRouterAddress,
        address linkTokenAddress,
        uint64 currentChainSelector
    ) ERC721("Cross Chain NFT", "XNFT") {
        if (ccipRouterAddress == address(0)) revert InvalidRouter(address(0));
        i_ccipRouter = IRouterClient(ccipRouterAddress);
        i_linkToken = LinkTokenInterface(linkTokenAddress);
        i_currentChainSelector = currentChainSelector;
    }

    function mint() external onlyOnArbitrumSepolia {
        uint256 tokenId = _nextTokenId++;
        string memory uri = characters[tokenId % characters.length];
        _safeMint(msg.sender, tokenId);
        _setTokenURI(tokenId, uri);
    }

    function enableChain(
        uint64 chainSelector,
        address xNftAddress,
        bytes memory ccipExtraArgs
    ) external onlyOwner onlyOtherChains(chainSelector) {
        s_chains[chainSelector] = XNftDetails({
            xNftAddress: xNftAddress,
            ccipExtraArgsBytes: ccipExtraArgs
        });

        emit ChainEnabled(chainSelector, xNftAddress, ccipExtraArgs);
    }

    function disableChain(
        uint64 chainSelector
    ) external onlyOwner onlyOtherChains(chainSelector) {
        delete s_chains[chainSelector];

        emit ChainDisabled(chainSelector);
    }

    function crossChainTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint64 destinationChainSelector,
        PayFeesIn payFeesIn
    )
        external
        nonReentrant
        onlyEnabledChain(destinationChainSelector)
        returns (bytes32 messageId)
    {
        string memory tokenUri = tokenURI(tokenId);
        _burn(tokenId);

        Client.EVM2AnyMessage memory message = Client.EVM2AnyMessage({
            receiver: abi.encode(
                s_chains[destinationChainSelector].xNftAddress
            ),
            data: abi.encode(from, to, tokenId, tokenUri),
            tokenAmounts: new Client.EVMTokenAmount[](0),
            extraArgs: s_chains[destinationChainSelector].ccipExtraArgsBytes,
            feeToken: payFeesIn == PayFeesIn.LINK
                ? address(i_linkToken)
                : address(0)
        });

        // Get the fee required to send the CCIP message
        uint256 fees = i_ccipRouter.getFee(destinationChainSelector, message);

        if (payFeesIn == PayFeesIn.LINK) {
            if (fees > i_linkToken.balanceOf(address(this)))
                revert NotEnoughBalanceForFees(
                    i_linkToken.balanceOf(address(this)),
                    fees
                );

            // Approve the Router to transfer LINK tokens on contract's behalf. It will spend the fees in LINK
            i_linkToken.approve(address(i_ccipRouter), fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend(
                destinationChainSelector,
                message
            );
        } else {
            if (fees > address(this).balance)
                revert NotEnoughBalanceForFees(address(this).balance, fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend{value: fees}(
                destinationChainSelector,
                message
            );
        }

        emit CrossChainSent(
            from,
            to,
            tokenId,
            i_currentChainSelector,
            destinationChainSelector
        );
    }

    /// @inheritdoc IAny2EVMMessageReceiver
    function ccipReceive(
        Client.Any2EVMMessage calldata message
    )
        external
        virtual
        override
        onlyRouter
        nonReentrant
        onlyEnabledChain(message.sourceChainSelector)
        onlyEnabledSender(
            message.sourceChainSelector,
            abi.decode(message.sender, (address))
        )
    {
        uint64 sourceChainSelector = message.sourceChainSelector;
        (
            address from,
            address to,
            uint256 tokenId,
            string memory tokenUri
        ) = abi.decode(message.data, (address, address, uint256, string));

        _safeMint(to, tokenId);
        _setTokenURI(tokenId, tokenUri);

        emit CrossChainReceived(
            from,
            to,
            tokenId,
            sourceChainSelector,
            i_currentChainSelector
        );
    }

    function withdraw(address _beneficiary) public onlyOwner {
        uint256 amount = address(this).balance;

        if (amount == 0) revert NothingToWithdraw();

        (bool sent, ) = _beneficiary.call{value: amount}("");

        if (!sent) revert FailedToWithdrawEth(msg.sender, _beneficiary, amount);
    }

    function withdrawToken(
        address _beneficiary,
        address _token
    ) public onlyOwner {
        uint256 amount = IERC20(_token).balanceOf(address(this));

        if (amount == 0) revert NothingToWithdraw();

        IERC20(_token).safeTransfer(_beneficiary, amount);
    }

    function tokenURI(
        uint256 tokenId
    ) public view override(ERC721, ERC721URIStorage) returns (string memory) {
        return super.tokenURI(tokenId);
    }

    function getCCIPRouter() public view returns (address) {
        return address(i_ccipRouter);
    }

    function supportsInterface(
        bytes4 interfaceId
    ) public view override(ERC721, ERC721URIStorage) returns (bool) {
        return
            interfaceId == type(IAny2EVMMessageReceiver).interfaceId ||
            super.supportsInterface(interfaceId);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import {ERC721URIStorage} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import {ERC721Burnable} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import {IERC20} from "@openzeppelin/contracts/interfaces/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import {Client} from "@chainlink/contracts-ccip/src/v0.8/ccip/libraries/Client.sol";
import {IRouterClient} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IRouterClient.sol";
import {IAny2EVMMessageReceiver} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IAny2EVMMessageReceiver.sol";
import {OwnerIsCreator} from "@chainlink/contracts-ccip/src/v0.8/shared/access/OwnerIsCreator.sol";
import {LinkTokenInterface} from "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";

/**
 * THIS IS AN EXAMPLE CONTRACT THAT USES HARDCODED VALUES FOR CLARITY.
 * THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE.
 * DO NOT USE THIS CODE IN PRODUCTION.
 */
contract XNFT is
    ERC721,
    ERC721URIStorage,
    ERC721Burnable,
    IAny2EVMMessageReceiver,
    ReentrancyGuard,
    OwnerIsCreator
{
    using SafeERC20 for IERC20;

    enum PayFeesIn {
        Native,
        LINK
    }

    error InvalidRouter(address router);
    error OnlyOnArbitrumSepolia();
    error NotEnoughBalanceForFees(
        uint256 currentBalance,
        uint256 calculatedFees
    );
    error NothingToWithdraw();
    error FailedToWithdrawEth(address owner, address target, uint256 value);
    error ChainNotEnabled(uint64 chainSelector);
    error SenderNotEnabled(address sender);
    error OperationNotAllowedOnCurrentChain(uint64 chainSelector);

    struct XNftDetails {
        address xNftAddress;
        bytes ccipExtraArgsBytes;
    }

    uint256 constant ARBITRUM_SEPOLIA_CHAIN_ID = 421614;

    string[] characters = [
        "https://ipfs.io/ipfs/QmTgqnhFBMkfT9s8PHKcdXBn1f5bG3Q5hmBaR4U6hoTvb1?filename=Chainlink_Elf.png",
        "https://ipfs.io/ipfs/QmZGQA92ri1jfzSu61JRaNQXYg1bLuM7p8YT83DzFA2KLH?filename=Chainlink_Knight.png",
        "https://ipfs.io/ipfs/QmW1toapYs7M29rzLXTENn3pbvwe8ioikX1PwzACzjfdHP?filename=Chainlink_Orc.png",
        "https://ipfs.io/ipfs/QmPMwQtFpEdKrUjpQJfoTeZS1aVSeuJT6Mof7uV29AcUpF?filename=Chainlink_Witch.png"
    ];

    IRouterClient internal immutable i_ccipRouter;
    LinkTokenInterface internal immutable i_linkToken;
    uint64 private immutable i_currentChainSelector;

    uint256 private _nextTokenId;

    mapping(uint64 destChainSelector => XNftDetails xNftDetailsPerChain)
        public s_chains;

    event ChainEnabled(
        uint64 chainSelector,
        address xNftAddress,
        bytes ccipExtraArgs
    );
    event ChainDisabled(uint64 chainSelector);
    event CrossChainSent(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );
    event CrossChainReceived(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );

    modifier onlyRouter() {
        if (msg.sender != address(i_ccipRouter))
            revert InvalidRouter(msg.sender);
        _;
    }

    modifier onlyOnArbitrumSepolia() {
        if (block.chainid != ARBITRUM_SEPOLIA_CHAIN_ID)
            revert OnlyOnArbitrumSepolia();
        _;
    }

    modifier onlyEnabledChain(uint64 _chainSelector) {
        if (s_chains[_chainSelector].xNftAddress == address(0))
            revert ChainNotEnabled(_chainSelector);
        _;
    }

    modifier onlyEnabledSender(uint64 _chainSelector, address _sender) {
        if (s_chains[_chainSelector].xNftAddress != _sender)
            revert SenderNotEnabled(_sender);
        _;
    }

    modifier onlyOtherChains(uint64 _chainSelector) {
        if (_chainSelector == i_currentChainSelector)
            revert OperationNotAllowedOnCurrentChain(_chainSelector);
        _;
    }

    constructor(
        address ccipRouterAddress,
        address linkTokenAddress,
        uint64 currentChainSelector
    ) ERC721("Cross Chain NFT", "XNFT") {
        if (ccipRouterAddress == address(0)) revert InvalidRouter(address(0));
        i_ccipRouter = IRouterClient(ccipRouterAddress);
        i_linkToken = LinkTokenInterface(linkTokenAddress);
        i_currentChainSelector = currentChainSelector;
    }

    function mint() external onlyOnArbitrumSepolia {
        uint256 tokenId = _nextTokenId++;
        string memory uri = characters[tokenId % characters.length];
        _safeMint(msg.sender, tokenId);
        _setTokenURI(tokenId, uri);
    }

    function enableChain(
        uint64 chainSelector,
        address xNftAddress,
        bytes memory ccipExtraArgs
    ) external onlyOwner onlyOtherChains(chainSelector) {
        s_chains[chainSelector] = XNftDetails({
            xNftAddress: xNftAddress,
            ccipExtraArgsBytes: ccipExtraArgs
        });

        emit ChainEnabled(chainSelector, xNftAddress, ccipExtraArgs);
    }

    function disableChain(
        uint64 chainSelector
    ) external onlyOwner onlyOtherChains(chainSelector) {
        delete s_chains[chainSelector];

        emit ChainDisabled(chainSelector);
    }

    function crossChainTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint64 destinationChainSelector,
        PayFeesIn payFeesIn
    )
        external
        nonReentrant
        onlyEnabledChain(destinationChainSelector)
        returns (bytes32 messageId)
    {
        string memory tokenUri = tokenURI(tokenId);
        _burn(tokenId);

        Client.EVM2AnyMessage memory message = Client.EVM2AnyMessage({
            receiver: abi.encode(
                s_chains[destinationChainSelector].xNftAddress
            ),
            data: abi.encode(from, to, tokenId, tokenUri),
            tokenAmounts: new Client.EVMTokenAmount[](0),
            extraArgs: s_chains[destinationChainSelector].ccipExtraArgsBytes,
            feeToken: payFeesIn == PayFeesIn.LINK
                ? address(i_linkToken)
                : address(0)
        });

        // Get the fee required to send the CCIP message
        uint256 fees = i_ccipRouter.getFee(destinationChainSelector, message);

        if (payFeesIn == PayFeesIn.LINK) {
            if (fees > i_linkToken.balanceOf(address(this)))
                revert NotEnoughBalanceForFees(
                    i_linkToken.balanceOf(address(this)),
                    fees
                );

            // Approve the Router to transfer LINK tokens on contract's behalf. It will spend the fees in LINK
            i_linkToken.approve(address(i_ccipRouter), fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend(
                destinationChainSelector,
                message
            );
        } else {
            if (fees > address(this).balance)
                revert NotEnoughBalanceForFees(address(this).balance, fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend{value: fees}(
                destinationChainSelector,
                message
            );
        }

        emit CrossChainSent(
            from,
            to,
            tokenId,
            i_currentChainSelector,
            destinationChainSelector
        );
    }

    /// @inheritdoc IAny2EVMMessageReceiver
    function ccipReceive(
        Client.Any2EVMMessage calldata message
    )
        external
        virtual
        override
        onlyRouter
        nonReentrant
        onlyEnabledChain(message.sourceChainSelector)
        onlyEnabledSender(
            message.sourceChainSelector,
            abi.decode(message.sender, (address))
        )
    {
        uint64 sourceChainSelector = message.sourceChainSelector;
        (
            address from,
            address to,
            uint256 tokenId,
            string memory tokenUri
        ) = abi.decode(message.data, (address, address, uint256, string));

        _safeMint(to, tokenId);
        _setTokenURI(tokenId, tokenUri);

        emit CrossChainReceived(
            from,
            to,
            tokenId,
            sourceChainSelector,
            i_currentChainSelector
        );
    }

    function withdraw(address _beneficiary) public onlyOwner {
        uint256 amount = address(this).balance;

        if (amount == 0) revert NothingToWithdraw();

        (bool sent, ) = _beneficiary.call{value: amount}("");

        if (!sent) revert FailedToWithdrawEth(msg.sender, _beneficiary, amount);
    }

    function withdrawToken(
        address _beneficiary,
        address _token
    ) public onlyOwner {
        uint256 amount = IERC20(_token).balanceOf(address(this));

        if (amount == 0) revert NothingToWithdraw();

        IERC20(_token).safeTransfer(_beneficiary, amount);
    }

    function tokenURI(
        uint256 tokenId
    ) public view override(ERC721, ERC721URIStorage) returns (string memory) {
        return super.tokenURI(tokenId);
    }

    function getCCIPRouter() public view returns (address) {
        return address(i_ccipRouter);
    }

    function supportsInterface(
        bytes4 interfaceId
    ) public view override(ERC721, ERC721URIStorage) returns (bool) {
        return
            interfaceId == type(IAny2EVMMessageReceiver).interfaceId ||
            super.supportsInterface(interfaceId);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import {ERC721URIStorage} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import {ERC721Burnable} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import {IERC20} from "@openzeppelin/contracts/interfaces/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import {Client} from "@chainlink/contracts-ccip/src/v0.8/ccip/libraries/Client.sol";
import {IRouterClient} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IRouterClient.sol";
import {IAny2EVMMessageReceiver} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IAny2EVMMessageReceiver.sol";
import {OwnerIsCreator} from "@chainlink/contracts-ccip/src/v0.8/shared/access/OwnerIsCreator.sol";
import {LinkTokenInterface} from "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";

/**
 * THIS IS AN EXAMPLE CONTRACT THAT USES HARDCODED VALUES FOR CLARITY.
 * THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE.
 * DO NOT USE THIS CODE IN PRODUCTION.
 */
contract XNFT is
    ERC721,
    ERC721URIStorage,
    ERC721Burnable,
    IAny2EVMMessageReceiver,
    ReentrancyGuard,
    OwnerIsCreator
{
    using SafeERC20 for IERC20;

    enum PayFeesIn {
        Native,
        LINK
    }

    error InvalidRouter(address router);
    error OnlyOnArbitrumSepolia();
    error NotEnoughBalanceForFees(
        uint256 currentBalance,
        uint256 calculatedFees
    );
    error NothingToWithdraw();
    error FailedToWithdrawEth(address owner, address target, uint256 value);
    error ChainNotEnabled(uint64 chainSelector);
    error SenderNotEnabled(address sender);
    error OperationNotAllowedOnCurrentChain(uint64 chainSelector);

    struct XNftDetails {
        address xNftAddress;
        bytes ccipExtraArgsBytes;
    }

    uint256 constant ARBITRUM_SEPOLIA_CHAIN_ID = 421614;

    string[] characters = [
        "https://ipfs.io/ipfs/QmTgqnhFBMkfT9s8PHKcdXBn1f5bG3Q5hmBaR4U6hoTvb1?filename=Chainlink_Elf.png",
        "https://ipfs.io/ipfs/QmZGQA92ri1jfzSu61JRaNQXYg1bLuM7p8YT83DzFA2KLH?filename=Chainlink_Knight.png",
        "https://ipfs.io/ipfs/QmW1toapYs7M29rzLXTENn3pbvwe8ioikX1PwzACzjfdHP?filename=Chainlink_Orc.png",
        "https://ipfs.io/ipfs/QmPMwQtFpEdKrUjpQJfoTeZS1aVSeuJT6Mof7uV29AcUpF?filename=Chainlink_Witch.png"
    ];

    IRouterClient internal immutable i_ccipRouter;
    LinkTokenInterface internal immutable i_linkToken;
    uint64 private immutable i_currentChainSelector;

    uint256 private _nextTokenId;

    mapping(uint64 destChainSelector => XNftDetails xNftDetailsPerChain)
        public s_chains;

    event ChainEnabled(
        uint64 chainSelector,
        address xNftAddress,
        bytes ccipExtraArgs
    );
    event ChainDisabled(uint64 chainSelector);
    event CrossChainSent(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );
    event CrossChainReceived(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );

    modifier onlyRouter() {
        if (msg.sender != address(i_ccipRouter))
            revert InvalidRouter(msg.sender);
        _;
    }

    modifier onlyOnArbitrumSepolia() {
        if (block.chainid != ARBITRUM_SEPOLIA_CHAIN_ID)
            revert OnlyOnArbitrumSepolia();
        _;
    }

    modifier onlyEnabledChain(uint64 _chainSelector) {
        if (s_chains[_chainSelector].xNftAddress == address(0))
            revert ChainNotEnabled(_chainSelector);
        _;
    }

    modifier onlyEnabledSender(uint64 _chainSelector, address _sender) {
        if (s_chains[_chainSelector].xNftAddress != _sender)
            revert SenderNotEnabled(_sender);
        _;
    }

    modifier onlyOtherChains(uint64 _chainSelector) {
        if (_chainSelector == i_currentChainSelector)
            revert OperationNotAllowedOnCurrentChain(_chainSelector);
        _;
    }

    constructor(
        address ccipRouterAddress,
        address linkTokenAddress,
        uint64 currentChainSelector
    ) ERC721("Cross Chain NFT", "XNFT") {
        if (ccipRouterAddress == address(0)) revert InvalidRouter(address(0));
        i_ccipRouter = IRouterClient(ccipRouterAddress);
        i_linkToken = LinkTokenInterface(linkTokenAddress);
        i_currentChainSelector = currentChainSelector;
    }

    function mint() external onlyOnArbitrumSepolia {
        uint256 tokenId = _nextTokenId++;
        string memory uri = characters[tokenId % characters.length];
        _safeMint(msg.sender, tokenId);
        _setTokenURI(tokenId, uri);
    }

    function enableChain(
        uint64 chainSelector,
        address xNftAddress,
        bytes memory ccipExtraArgs
    ) external onlyOwner onlyOtherChains(chainSelector) {
        s_chains[chainSelector] = XNftDetails({
            xNftAddress: xNftAddress,
            ccipExtraArgsBytes: ccipExtraArgs
        });

        emit ChainEnabled(chainSelector, xNftAddress, ccipExtraArgs);
    }

    function disableChain(
        uint64 chainSelector
    ) external onlyOwner onlyOtherChains(chainSelector) {
        delete s_chains[chainSelector];

        emit ChainDisabled(chainSelector);
    }

    function crossChainTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint64 destinationChainSelector,
        PayFeesIn payFeesIn
    )
        external
        nonReentrant
        onlyEnabledChain(destinationChainSelector)
        returns (bytes32 messageId)
    {
        string memory tokenUri = tokenURI(tokenId);
        _burn(tokenId);

        Client.EVM2AnyMessage memory message = Client.EVM2AnyMessage({
            receiver: abi.encode(
                s_chains[destinationChainSelector].xNftAddress
            ),
            data: abi.encode(from, to, tokenId, tokenUri),
            tokenAmounts: new Client.EVMTokenAmount[](0),
            extraArgs: s_chains[destinationChainSelector].ccipExtraArgsBytes,
            feeToken: payFeesIn == PayFeesIn.LINK
                ? address(i_linkToken)
                : address(0)
        });

        // Get the fee required to send the CCIP message
        uint256 fees = i_ccipRouter.getFee(destinationChainSelector, message);

        if (payFeesIn == PayFeesIn.LINK) {
            if (fees > i_linkToken.balanceOf(address(this)))
                revert NotEnoughBalanceForFees(
                    i_linkToken.balanceOf(address(this)),
                    fees
                );

            // Approve the Router to transfer LINK tokens on contract's behalf. It will spend the fees in LINK
            i_linkToken.approve(address(i_ccipRouter), fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend(
                destinationChainSelector,
                message
            );
        } else {
            if (fees > address(this).balance)
                revert NotEnoughBalanceForFees(address(this).balance, fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend{value: fees}(
                destinationChainSelector,
                message
            );
        }

        emit CrossChainSent(
            from,
            to,
            tokenId,
            i_currentChainSelector,
            destinationChainSelector
        );
    }

    /// @inheritdoc IAny2EVMMessageReceiver
    function ccipReceive(
        Client.Any2EVMMessage calldata message
    )
        external
        virtual
        override
        onlyRouter
        nonReentrant
        onlyEnabledChain(message.sourceChainSelector)
        onlyEnabledSender(
            message.sourceChainSelector,
            abi.decode(message.sender, (address))
        )
    {
        uint64 sourceChainSelector = message.sourceChainSelector;
        (
            address from,
            address to,
            uint256 tokenId,
            string memory tokenUri
        ) = abi.decode(message.data, (address, address, uint256, string));

        _safeMint(to, tokenId);
        _setTokenURI(tokenId, tokenUri);

        emit CrossChainReceived(
            from,
            to,
            tokenId,
            sourceChainSelector,
            i_currentChainSelector
        );
    }

    function withdraw(address _beneficiary) public onlyOwner {
        uint256 amount = address(this).balance;

        if (amount == 0) revert NothingToWithdraw();

        (bool sent, ) = _beneficiary.call{value: amount}("");

        if (!sent) revert FailedToWithdrawEth(msg.sender, _beneficiary, amount);
    }

    function withdrawToken(
        address _beneficiary,
        address _token
    ) public onlyOwner {
        uint256 amount = IERC20(_token).balanceOf(address(this));

        if (amount == 0) revert NothingToWithdraw();

        IERC20(_token).safeTransfer(_beneficiary, amount);
    }

    function tokenURI(
        uint256 tokenId
    ) public view override(ERC721, ERC721URIStorage) returns (string memory) {
        return super.tokenURI(tokenId);
    }

    function getCCIPRouter() public view returns (address) {
        return address(i_ccipRouter);
    }

    function supportsInterface(
        bytes4 interfaceId
    ) public view override(ERC721, ERC721URIStorage) returns (bool) {
        return
            interfaceId == type(IAny2EVMMessageReceiver).interfaceId ||
            super.supportsInterface(interfaceId);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import {ERC721URIStorage} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import {ERC721Burnable} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import {IERC20} from "@openzeppelin/contracts/interfaces/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import {Client} from "@chainlink/contracts-ccip/src/v0.8/ccip/libraries/Client.sol";
import {IRouterClient} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IRouterClient.sol";
import {IAny2EVMMessageReceiver} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IAny2EVMMessageReceiver.sol";
import {OwnerIsCreator} from "@chainlink/contracts-ccip/src/v0.8/shared/access/OwnerIsCreator.sol";
import {LinkTokenInterface} from "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";

/**
 * THIS IS AN EXAMPLE CONTRACT THAT USES HARDCODED VALUES FOR CLARITY.
 * THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE.
 * DO NOT USE THIS CODE IN PRODUCTION.
 */
contract XNFT is
    ERC721,
    ERC721URIStorage,
    ERC721Burnable,
    IAny2EVMMessageReceiver,
    ReentrancyGuard,
    OwnerIsCreator
{
    using SafeERC20 for IERC20;

    enum PayFeesIn {
        Native,
        LINK
    }

    error InvalidRouter(address router);
    error OnlyOnArbitrumSepolia();
    error NotEnoughBalanceForFees(
        uint256 currentBalance,
        uint256 calculatedFees
    );
    error NothingToWithdraw();
    error FailedToWithdrawEth(address owner, address target, uint256 value);
    error ChainNotEnabled(uint64 chainSelector);
    error SenderNotEnabled(address sender);
    error OperationNotAllowedOnCurrentChain(uint64 chainSelector);

    struct XNftDetails {
        address xNftAddress;
        bytes ccipExtraArgsBytes;
    }

    uint256 constant ARBITRUM_SEPOLIA_CHAIN_ID = 421614;

    string[] characters = [
        "https://ipfs.io/ipfs/QmTgqnhFBMkfT9s8PHKcdXBn1f5bG3Q5hmBaR4U6hoTvb1?filename=Chainlink_Elf.png",
        "https://ipfs.io/ipfs/QmZGQA92ri1jfzSu61JRaNQXYg1bLuM7p8YT83DzFA2KLH?filename=Chainlink_Knight.png",
        "https://ipfs.io/ipfs/QmW1toapYs7M29rzLXTENn3pbvwe8ioikX1PwzACzjfdHP?filename=Chainlink_Orc.png",
        "https://ipfs.io/ipfs/QmPMwQtFpEdKrUjpQJfoTeZS1aVSeuJT6Mof7uV29AcUpF?filename=Chainlink_Witch.png"
    ];

    IRouterClient internal immutable i_ccipRouter;
    LinkTokenInterface internal immutable i_linkToken;
    uint64 private immutable i_currentChainSelector;

    uint256 private _nextTokenId;

    mapping(uint64 destChainSelector => XNftDetails xNftDetailsPerChain)
        public s_chains;

    event ChainEnabled(
        uint64 chainSelector,
        address xNftAddress,
        bytes ccipExtraArgs
    );
    event ChainDisabled(uint64 chainSelector);
    event CrossChainSent(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );
    event CrossChainReceived(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );

    modifier onlyRouter() {
        if (msg.sender != address(i_ccipRouter))
            revert InvalidRouter(msg.sender);
        _;
    }

    modifier onlyOnArbitrumSepolia() {
        if (block.chainid != ARBITRUM_SEPOLIA_CHAIN_ID)
            revert OnlyOnArbitrumSepolia();
        _;
    }

    modifier onlyEnabledChain(uint64 _chainSelector) {
        if (s_chains[_chainSelector].xNftAddress == address(0))
            revert ChainNotEnabled(_chainSelector);
        _;
    }

    modifier onlyEnabledSender(uint64 _chainSelector, address _sender) {
        if (s_chains[_chainSelector].xNftAddress != _sender)
            revert SenderNotEnabled(_sender);
        _;
    }

    modifier onlyOtherChains(uint64 _chainSelector) {
        if (_chainSelector == i_currentChainSelector)
            revert OperationNotAllowedOnCurrentChain(_chainSelector);
        _;
    }

    constructor(
        address ccipRouterAddress,
        address linkTokenAddress,
        uint64 currentChainSelector
    ) ERC721("Cross Chain NFT", "XNFT") {
        if (ccipRouterAddress == address(0)) revert InvalidRouter(address(0));
        i_ccipRouter = IRouterClient(ccipRouterAddress);
        i_linkToken = LinkTokenInterface(linkTokenAddress);
        i_currentChainSelector = currentChainSelector;
    }

    function mint() external onlyOnArbitrumSepolia {
        uint256 tokenId = _nextTokenId++;
        string memory uri = characters[tokenId % characters.length];
        _safeMint(msg.sender, tokenId);
        _setTokenURI(tokenId, uri);
    }

    function enableChain(
        uint64 chainSelector,
        address xNftAddress,
        bytes memory ccipExtraArgs
    ) external onlyOwner onlyOtherChains(chainSelector) {
        s_chains[chainSelector] = XNftDetails({
            xNftAddress: xNftAddress,
            ccipExtraArgsBytes: ccipExtraArgs
        });

        emit ChainEnabled(chainSelector, xNftAddress, ccipExtraArgs);
    }

    function disableChain(
        uint64 chainSelector
    ) external onlyOwner onlyOtherChains(chainSelector) {
        delete s_chains[chainSelector];

        emit ChainDisabled(chainSelector);
    }

    function crossChainTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint64 destinationChainSelector,
        PayFeesIn payFeesIn
    )
        external
        nonReentrant
        onlyEnabledChain(destinationChainSelector)
        returns (bytes32 messageId)
    {
        string memory tokenUri = tokenURI(tokenId);
        _burn(tokenId);

        Client.EVM2AnyMessage memory message = Client.EVM2AnyMessage({
            receiver: abi.encode(
                s_chains[destinationChainSelector].xNftAddress
            ),
            data: abi.encode(from, to, tokenId, tokenUri),
            tokenAmounts: new Client.EVMTokenAmount[](0),
            extraArgs: s_chains[destinationChainSelector].ccipExtraArgsBytes,
            feeToken: payFeesIn == PayFeesIn.LINK
                ? address(i_linkToken)
                : address(0)
        });

        // Get the fee required to send the CCIP message
        uint256 fees = i_ccipRouter.getFee(destinationChainSelector, message);

        if (payFeesIn == PayFeesIn.LINK) {
            if (fees > i_linkToken.balanceOf(address(this)))
                revert NotEnoughBalanceForFees(
                    i_linkToken.balanceOf(address(this)),
                    fees
                );

            // Approve the Router to transfer LINK tokens on contract's behalf. It will spend the fees in LINK
            i_linkToken.approve(address(i_ccipRouter), fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend(
                destinationChainSelector,
                message
            );
        } else {
            if (fees > address(this).balance)
                revert NotEnoughBalanceForFees(address(this).balance, fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend{value: fees}(
                destinationChainSelector,
                message
            );
        }

        emit CrossChainSent(
            from,
            to,
            tokenId,
            i_currentChainSelector,
            destinationChainSelector
        );
    }

    /// @inheritdoc IAny2EVMMessageReceiver
    function ccipReceive(
        Client.Any2EVMMessage calldata message
    )
        external
        virtual
        override
        onlyRouter
        nonReentrant
        onlyEnabledChain(message.sourceChainSelector)
        onlyEnabledSender(
            message.sourceChainSelector,
            abi.decode(message.sender, (address))
        )
    {
        uint64 sourceChainSelector = message.sourceChainSelector;
        (
            address from,
            address to,
            uint256 tokenId,
            string memory tokenUri
        ) = abi.decode(message.data, (address, address, uint256, string));

        _safeMint(to, tokenId);
        _setTokenURI(tokenId, tokenUri);

        emit CrossChainReceived(
            from,
            to,
            tokenId,
            sourceChainSelector,
            i_currentChainSelector
        );
    }

    function withdraw(address _beneficiary) public onlyOwner {
        uint256 amount = address(this).balance;

        if (amount == 0) revert NothingToWithdraw();

        (bool sent, ) = _beneficiary.call{value: amount}("");

        if (!sent) revert FailedToWithdrawEth(msg.sender, _beneficiary, amount);
    }

    function withdrawToken(
        address _beneficiary,
        address _token
    ) public onlyOwner {
        uint256 amount = IERC20(_token).balanceOf(address(this));

        if (amount == 0) revert NothingToWithdraw();

        IERC20(_token).safeTransfer(_beneficiary, amount);
    }

    function tokenURI(
        uint256 tokenId
    ) public view override(ERC721, ERC721URIStorage) returns (string memory) {
        return super.tokenURI(tokenId);
    }

    function getCCIPRouter() public view returns (address) {
        return address(i_ccipRouter);
    }

    function supportsInterface(
        bytes4 interfaceId
    ) public view override(ERC721, ERC721URIStorage) returns (bool) {
        return
            interfaceId == type(IAny2EVMMessageReceiver).interfaceId ||
            super.supportsInterface(interfaceId);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import {ERC721URIStorage} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import {ERC721Burnable} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import {IERC20} from "@openzeppelin/contracts/interfaces/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import {Client} from "@chainlink/contracts-ccip/src/v0.8/ccip/libraries/Client.sol";
import {IRouterClient} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IRouterClient.sol";
import {IAny2EVMMessageReceiver} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IAny2EVMMessageReceiver.sol";
import {OwnerIsCreator} from "@chainlink/contracts-ccip/src/v0.8/shared/access/OwnerIsCreator.sol";
import {LinkTokenInterface} from "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";

/**
 * THIS IS AN EXAMPLE CONTRACT THAT USES HARDCODED VALUES FOR CLARITY.
 * THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE.
 * DO NOT USE THIS CODE IN PRODUCTION.
 */
contract XNFT is
    ERC721,
    ERC721URIStorage,
    ERC721Burnable,
    IAny2EVMMessageReceiver,
    ReentrancyGuard,
    OwnerIsCreator
{
    using SafeERC20 for IERC20;

    enum PayFeesIn {
        Native,
        LINK
    }

    error InvalidRouter(address router);
    error OnlyOnArbitrumSepolia();
    error NotEnoughBalanceForFees(
        uint256 currentBalance,
        uint256 calculatedFees
    );
    error NothingToWithdraw();
    error FailedToWithdrawEth(address owner, address target, uint256 value);
    error ChainNotEnabled(uint64 chainSelector);
    error SenderNotEnabled(address sender);
    error OperationNotAllowedOnCurrentChain(uint64 chainSelector);

    struct XNftDetails {
        address xNftAddress;
        bytes ccipExtraArgsBytes;
    }

    uint256 constant ARBITRUM_SEPOLIA_CHAIN_ID = 421614;

    string[] characters = [
        "https://ipfs.io/ipfs/QmTgqnhFBMkfT9s8PHKcdXBn1f5bG3Q5hmBaR4U6hoTvb1?filename=Chainlink_Elf.png",
        "https://ipfs.io/ipfs/QmZGQA92ri1jfzSu61JRaNQXYg1bLuM7p8YT83DzFA2KLH?filename=Chainlink_Knight.png",
        "https://ipfs.io/ipfs/QmW1toapYs7M29rzLXTENn3pbvwe8ioikX1PwzACzjfdHP?filename=Chainlink_Orc.png",
        "https://ipfs.io/ipfs/QmPMwQtFpEdKrUjpQJfoTeZS1aVSeuJT6Mof7uV29AcUpF?filename=Chainlink_Witch.png"
    ];

    IRouterClient internal immutable i_ccipRouter;
    LinkTokenInterface internal immutable i_linkToken;
    uint64 private immutable i_currentChainSelector;

    uint256 private _nextTokenId;

    mapping(uint64 destChainSelector => XNftDetails xNftDetailsPerChain)
        public s_chains;

    event ChainEnabled(
        uint64 chainSelector,
        address xNftAddress,
        bytes ccipExtraArgs
    );
    event ChainDisabled(uint64 chainSelector);
    event CrossChainSent(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );
    event CrossChainReceived(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );

    modifier onlyRouter() {
        if (msg.sender != address(i_ccipRouter))
            revert InvalidRouter(msg.sender);
        _;
    }

    modifier onlyOnArbitrumSepolia() {
        if (block.chainid != ARBITRUM_SEPOLIA_CHAIN_ID)
            revert OnlyOnArbitrumSepolia();
        _;
    }

    modifier onlyEnabledChain(uint64 _chainSelector) {
        if (s_chains[_chainSelector].xNftAddress == address(0))
            revert ChainNotEnabled(_chainSelector);
        _;
    }

    modifier onlyEnabledSender(uint64 _chainSelector, address _sender) {
        if (s_chains[_chainSelector].xNftAddress != _sender)
            revert SenderNotEnabled(_sender);
        _;
    }

    modifier onlyOtherChains(uint64 _chainSelector) {
        if (_chainSelector == i_currentChainSelector)
            revert OperationNotAllowedOnCurrentChain(_chainSelector);
        _;
    }

    constructor(
        address ccipRouterAddress,
        address linkTokenAddress,
        uint64 currentChainSelector
    ) ERC721("Cross Chain NFT", "XNFT") {
        if (ccipRouterAddress == address(0)) revert InvalidRouter(address(0));
        i_ccipRouter = IRouterClient(ccipRouterAddress);
        i_linkToken = LinkTokenInterface(linkTokenAddress);
        i_currentChainSelector = currentChainSelector;
    }

    function mint() external onlyOnArbitrumSepolia {
        uint256 tokenId = _nextTokenId++;
        string memory uri = characters[tokenId % characters.length];
        _safeMint(msg.sender, tokenId);
        _setTokenURI(tokenId, uri);
    }

    function enableChain(
        uint64 chainSelector,
        address xNftAddress,
        bytes memory ccipExtraArgs
    ) external onlyOwner onlyOtherChains(chainSelector) {
        s_chains[chainSelector] = XNftDetails({
            xNftAddress: xNftAddress,
            ccipExtraArgsBytes: ccipExtraArgs
        });

        emit ChainEnabled(chainSelector, xNftAddress, ccipExtraArgs);
    }

    function disableChain(
        uint64 chainSelector
    ) external onlyOwner onlyOtherChains(chainSelector) {
        delete s_chains[chainSelector];

        emit ChainDisabled(chainSelector);
    }

    function crossChainTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint64 destinationChainSelector,
        PayFeesIn payFeesIn
    )
        external
        nonReentrant
        onlyEnabledChain(destinationChainSelector)
        returns (bytes32 messageId)
    {
        string memory tokenUri = tokenURI(tokenId);
        _burn(tokenId);

        Client.EVM2AnyMessage memory message = Client.EVM2AnyMessage({
            receiver: abi.encode(
                s_chains[destinationChainSelector].xNftAddress
            ),
            data: abi.encode(from, to, tokenId, tokenUri),
            tokenAmounts: new Client.EVMTokenAmount[](0),
            extraArgs: s_chains[destinationChainSelector].ccipExtraArgsBytes,
            feeToken: payFeesIn == PayFeesIn.LINK
                ? address(i_linkToken)
                : address(0)
        });

        // Get the fee required to send the CCIP message
        uint256 fees = i_ccipRouter.getFee(destinationChainSelector, message);

        if (payFeesIn == PayFeesIn.LINK) {
            if (fees > i_linkToken.balanceOf(address(this)))
                revert NotEnoughBalanceForFees(
                    i_linkToken.balanceOf(address(this)),
                    fees
                );

            // Approve the Router to transfer LINK tokens on contract's behalf. It will spend the fees in LINK
            i_linkToken.approve(address(i_ccipRouter), fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend(
                destinationChainSelector,
                message
            );
        } else {
            if (fees > address(this).balance)
                revert NotEnoughBalanceForFees(address(this).balance, fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend{value: fees}(
                destinationChainSelector,
                message
            );
        }

        emit CrossChainSent(
            from,
            to,
            tokenId,
            i_currentChainSelector,
            destinationChainSelector
        );
    }

    /// @inheritdoc IAny2EVMMessageReceiver
    function ccipReceive(
        Client.Any2EVMMessage calldata message
    )
        external
        virtual
        override
        onlyRouter
        nonReentrant
        onlyEnabledChain(message.sourceChainSelector)
        onlyEnabledSender(
            message.sourceChainSelector,
            abi.decode(message.sender, (address))
        )
    {
        uint64 sourceChainSelector = message.sourceChainSelector;
        (
            address from,
            address to,
            uint256 tokenId,
            string memory tokenUri
        ) = abi.decode(message.data, (address, address, uint256, string));

        _safeMint(to, tokenId);
        _setTokenURI(tokenId, tokenUri);

        emit CrossChainReceived(
            from,
            to,
            tokenId,
            sourceChainSelector,
            i_currentChainSelector
        );
    }

    function withdraw(address _beneficiary) public onlyOwner {
        uint256 amount = address(this).balance;

        if (amount == 0) revert NothingToWithdraw();

        (bool sent, ) = _beneficiary.call{value: amount}("");

        if (!sent) revert FailedToWithdrawEth(msg.sender, _beneficiary, amount);
    }

    function withdrawToken(
        address _beneficiary,
        address _token
    ) public onlyOwner {
        uint256 amount = IERC20(_token).balanceOf(address(this));

        if (amount == 0) revert NothingToWithdraw();

        IERC20(_token).safeTransfer(_beneficiary, amount);
    }

    function tokenURI(
        uint256 tokenId
    ) public view override(ERC721, ERC721URIStorage) returns (string memory) {
        return super.tokenURI(tokenId);
    }

    function getCCIPRouter() public view returns (address) {
        return address(i_ccipRouter);
    }

    function supportsInterface(
        bytes4 interfaceId
    ) public view override(ERC721, ERC721URIStorage) returns (bool) {
        return
            interfaceId == type(IAny2EVMMessageReceiver).interfaceId ||
            super.supportsInterface(interfaceId);
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
import {ERC721URIStorage} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import {ERC721Burnable} from "@openzeppelin/contracts/token/ERC721/extensions/ERC721Burnable.sol";
import {IERC20} from "@openzeppelin/contracts/interfaces/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import {ReentrancyGuard} from "@openzeppelin/contracts/security/ReentrancyGuard.sol";
import {Client} from "@chainlink/contracts-ccip/src/v0.8/ccip/libraries/Client.sol";
import {IRouterClient} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IRouterClient.sol";
import {IAny2EVMMessageReceiver} from "@chainlink/contracts-ccip/src/v0.8/ccip/interfaces/IAny2EVMMessageReceiver.sol";
import {OwnerIsCreator} from "@chainlink/contracts-ccip/src/v0.8/shared/access/OwnerIsCreator.sol";
import {LinkTokenInterface} from "@chainlink/contracts/src/v0.8/interfaces/LinkTokenInterface.sol";

/**
 * THIS IS AN EXAMPLE CONTRACT THAT USES HARDCODED VALUES FOR CLARITY.
 * THIS IS AN EXAMPLE CONTRACT THAT USES UN-AUDITED CODE.
 * DO NOT USE THIS CODE IN PRODUCTION.
 */
contract XNFT is
    ERC721,
    ERC721URIStorage,
    ERC721Burnable,
    IAny2EVMMessageReceiver,
    ReentrancyGuard,
    OwnerIsCreator
{
    using SafeERC20 for IERC20;

    enum PayFeesIn {
        Native,
        LINK
    }

    error InvalidRouter(address router);
    error OnlyOnArbitrumSepolia();
    error NotEnoughBalanceForFees(
        uint256 currentBalance,
        uint256 calculatedFees
    );
    error NothingToWithdraw();
    error FailedToWithdrawEth(address owner, address target, uint256 value);
    error ChainNotEnabled(uint64 chainSelector);
    error SenderNotEnabled(address sender);
    error OperationNotAllowedOnCurrentChain(uint64 chainSelector);

    struct XNftDetails {
        address xNftAddress;
        bytes ccipExtraArgsBytes;
    }

    uint256 constant ARBITRUM_SEPOLIA_CHAIN_ID = 421614;

    string[] characters = [
        "https://ipfs.io/ipfs/QmTgqnhFBMkfT9s8PHKcdXBn1f5bG3Q5hmBaR4U6hoTvb1?filename=Chainlink_Elf.png",
        "https://ipfs.io/ipfs/QmZGQA92ri1jfzSu61JRaNQXYg1bLuM7p8YT83DzFA2KLH?filename=Chainlink_Knight.png",
        "https://ipfs.io/ipfs/QmW1toapYs7M29rzLXTENn3pbvwe8ioikX1PwzACzjfdHP?filename=Chainlink_Orc.png",
        "https://ipfs.io/ipfs/QmPMwQtFpEdKrUjpQJfoTeZS1aVSeuJT6Mof7uV29AcUpF?filename=Chainlink_Witch.png"
    ];

    IRouterClient internal immutable i_ccipRouter;
    LinkTokenInterface internal immutable i_linkToken;
    uint64 private immutable i_currentChainSelector;

    uint256 private _nextTokenId;

    mapping(uint64 destChainSelector => XNftDetails xNftDetailsPerChain)
        public s_chains;

    event ChainEnabled(
        uint64 chainSelector,
        address xNftAddress,
        bytes ccipExtraArgs
    );
    event ChainDisabled(uint64 chainSelector);
    event CrossChainSent(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );
    event CrossChainReceived(
        address from,
        address to,
        uint256 tokenId,
        uint64 sourceChainSelector,
        uint64 destinationChainSelector
    );

    modifier onlyRouter() {
        if (msg.sender != address(i_ccipRouter))
            revert InvalidRouter(msg.sender);
        _;
    }

    modifier onlyOnArbitrumSepolia() {
        if (block.chainid != ARBITRUM_SEPOLIA_CHAIN_ID)
            revert OnlyOnArbitrumSepolia();
        _;
    }

    modifier onlyEnabledChain(uint64 _chainSelector) {
        if (s_chains[_chainSelector].xNftAddress == address(0))
            revert ChainNotEnabled(_chainSelector);
        _;
    }

    modifier onlyEnabledSender(uint64 _chainSelector, address _sender) {
        if (s_chains[_chainSelector].xNftAddress != _sender)
            revert SenderNotEnabled(_sender);
        _;
    }

    modifier onlyOtherChains(uint64 _chainSelector) {
        if (_chainSelector == i_currentChainSelector)
            revert OperationNotAllowedOnCurrentChain(_chainSelector);
        _;
    }

    constructor(
        address ccipRouterAddress,
        address linkTokenAddress,
        uint64 currentChainSelector
    ) ERC721("Cross Chain NFT", "XNFT") {
        if (ccipRouterAddress == address(0)) revert InvalidRouter(address(0));
        i_ccipRouter = IRouterClient(ccipRouterAddress);
        i_linkToken = LinkTokenInterface(linkTokenAddress);
        i_currentChainSelector = currentChainSelector;
    }

    function mint() external onlyOnArbitrumSepolia {
        uint256 tokenId = _nextTokenId++;
        string memory uri = characters[tokenId % characters.length];
        _safeMint(msg.sender, tokenId);
        _setTokenURI(tokenId, uri);
    }

    function enableChain(
        uint64 chainSelector,
        address xNftAddress,
        bytes memory ccipExtraArgs
    ) external onlyOwner onlyOtherChains(chainSelector) {
        s_chains[chainSelector] = XNftDetails({
            xNftAddress: xNftAddress,
            ccipExtraArgsBytes: ccipExtraArgs
        });

        emit ChainEnabled(chainSelector, xNftAddress, ccipExtraArgs);
    }

    function disableChain(
        uint64 chainSelector
    ) external onlyOwner onlyOtherChains(chainSelector) {
        delete s_chains[chainSelector];

        emit ChainDisabled(chainSelector);
    }

    function crossChainTransferFrom(
        address from,
        address to,
        uint256 tokenId,
        uint64 destinationChainSelector,
        PayFeesIn payFeesIn
    )
        external
        nonReentrant
        onlyEnabledChain(destinationChainSelector)
        returns (bytes32 messageId)
    {
        string memory tokenUri = tokenURI(tokenId);
        _burn(tokenId);

        Client.EVM2AnyMessage memory message = Client.EVM2AnyMessage({
            receiver: abi.encode(
                s_chains[destinationChainSelector].xNftAddress
            ),
            data: abi.encode(from, to, tokenId, tokenUri),
            tokenAmounts: new Client.EVMTokenAmount[](0),
            extraArgs: s_chains[destinationChainSelector].ccipExtraArgsBytes,
            feeToken: payFeesIn == PayFeesIn.LINK
                ? address(i_linkToken)
                : address(0)
        });

        // Get the fee required to send the CCIP message
        uint256 fees = i_ccipRouter.getFee(destinationChainSelector, message);

        if (payFeesIn == PayFeesIn.LINK) {
            if (fees > i_linkToken.balanceOf(address(this)))
                revert NotEnoughBalanceForFees(
                    i_linkToken.balanceOf(address(this)),
                    fees
                );

            // Approve the Router to transfer LINK tokens on contract's behalf. It will spend the fees in LINK
            i_linkToken.approve(address(i_ccipRouter), fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend(
                destinationChainSelector,
                message
            );
        } else {
            if (fees > address(this).balance)
                revert NotEnoughBalanceForFees(address(this).balance, fees);

            // Send the message through the router and store the returned message ID
            messageId = i_ccipRouter.ccipSend{value: fees}(
                destinationChainSelector,
                message
            );
        }

        emit CrossChainSent(
            from,
            to,
            tokenId,
            i_currentChainSelector,
            destinationChainSelector
        );
    }

    /// @inheritdoc IAny2EVMMessageReceiver
    function ccipReceive(
        Client.Any2EVMMessage calldata message
    )
        external
        virtual
        override
        onlyRouter
        nonReentrant
        onlyEnabledChain(message.sourceChainSelector)
        onlyEnabledSender(
            message.sourceChainSelector,
            abi.decode(message.sender, (address))
        )
    {
        uint64 sourceChainSelector = message.sourceChainSelector;
        (
            address from,
            address to,
            uint256 tokenId,
            string memory tokenUri
        ) = abi.decode(message.data, (address, address, uint256, string));

        _safeMint(to, tokenId);
        _setTokenURI(tokenId, tokenUri);

        emit CrossChainReceived(
            from,
            to,
            tokenId,
            sourceChainSelector,
            i_currentChainSelector
        );
    }

    function withdraw(address _beneficiary) public onlyOwner {
        uint256 amount = address(this).balance;

        if (amount == 0) revert NothingToWithdraw();

        (bool sent, ) = _beneficiary.call{value: amount}("");

        if (!sent) revert FailedToWithdrawEth(msg.sender, _beneficiary, amount);
    }

    function withdrawToken(
        address _beneficiary,
        address _token
    ) public onlyOwner {
        uint256 amount = IERC20(_token).balanceOf(address(this));

        if (amount == 0) revert NothingToWithdraw();

        IERC20(_token).safeTransfer(_beneficiary, amount);
    }

    function tokenURI(
        uint256 tokenId
    ) public view override(ERC721, ERC721URIStorage) returns (string memory) {
        return super.tokenURI(tokenId);
    }

    function getCCIPRouter() public view returns (address) {
        return address(i_ccipRouter);
    }

    function supportsInterface(
        bytes4 interfaceId
    ) public view override(ERC721, ERC721URIStorage) returns (bool) {
        return
            interfaceId == type(IAny2EVMMessageReceiver).interfaceId ||
            super.supportsInterface(interfaceId);
    }
}

Exercise 2: Build Your First Cross-Chain NFT

CCIP Config Details

Getting started

The @chainlink/contracts-ccip NPM package

Faucet

Develop xNFT smart contract

Prepare for deployment

Step 1) Deploy XNFT.sol to Ethereum Sepolia

Step 2) Deploy XNFT.sol to Arbitrum Sepolia

Step 3) On Ethereum Sepolia, call enableChain function

Step 4) On Arbitrum Sepolia, call enableChain function

Step 5) On Arbitrum Sepolia, fund XNFT.sol with 3 LINK

Step 6) On Arbitrum Sepolia, mint new xNFT

Step 7) On Arbitrum Sepolia, crossTransferFrom xNFT

Exercise 2: Build Your First Cross-Chain NFT

CCIP Config Details

Getting started

The @chainlink/contracts-ccip NPM package

Faucet

Develop xNFT smart contract

Prepare for deployment

Step 1) Deploy XNFT.sol to Ethereum Sepolia

Step 2) Deploy XNFT.sol to Arbitrum Sepolia

Step 3) On Ethereum Sepolia, call enableChain function

Step 4) On Arbitrum Sepolia, call enableChain function

Step 5) On Arbitrum Sepolia, fund XNFT.sol with 3 LINK

Step 6) On Arbitrum Sepolia, mint new xNFT

Step 7) On Arbitrum Sepolia, crossTransferFrom xNFT

Option 2)

Option 2)

Exercise 2: Build Your First Cross-Chain NFT

hashtagCCIP Config Details

hashtagGetting started

hashtagThe @chainlink/contracts-ccip NPM package

hashtagFaucet

hashtagDevelop xNFT smart contract

hashtagPrepare for deployment

hashtagStep 1) Deploy XNFT.sol to Ethereum Sepolia

hashtagStep 2) Deploy XNFT.sol to Arbitrum Sepolia

hashtagStep 3) On Ethereum Sepolia, call enableChain function

hashtagStep 4) On Arbitrum Sepolia, call enableChain function

hashtagStep 5) On Arbitrum Sepolia, fund XNFT.sol with 3 LINK

hashtagStep 6) On Arbitrum Sepolia, mint new xNFT

hashtagStep 7) On Arbitrum Sepolia, crossTransferFrom xNFT

Exercise 2: Build Your First Cross-Chain NFT

hashtagCCIP Config Details

hashtagGetting started

hashtagThe @chainlink/contracts-ccip NPM package

hashtagFaucet

hashtagDevelop xNFT smart contract

hashtagPrepare for deployment

hashtagStep 1) Deploy XNFT.sol to Ethereum Sepolia

hashtagStep 2) Deploy XNFT.sol to Arbitrum Sepolia

hashtagStep 3) On Ethereum Sepolia, call enableChain function

hashtagStep 4) On Arbitrum Sepolia, call enableChain function

hashtagStep 5) On Arbitrum Sepolia, fund XNFT.sol with 3 LINK

hashtagStep 6) On Arbitrum Sepolia, mint new xNFT

hashtagStep 7) On Arbitrum Sepolia, crossTransferFrom xNFT

hashtagOption 2)

hashtagOption 2)

CCIP Config Details

Getting started

The @chainlink/contracts-ccip NPM package

Faucet

Develop xNFT smart contract

Prepare for deployment

Step 1) Deploy XNFT.sol to Ethereum Sepolia

Step 2) Deploy XNFT.sol to Arbitrum Sepolia

Step 3) On Ethereum Sepolia, call enableChain function

Step 4) On Arbitrum Sepolia, call enableChain function

Step 5) On Arbitrum Sepolia, fund XNFT.sol with 3 LINK

Step 6) On Arbitrum Sepolia, mint new xNFT

Step 7) On Arbitrum Sepolia, crossTransferFrom xNFT

CCIP Config Details

Getting started

The @chainlink/contracts-ccip NPM package

Faucet

Develop xNFT smart contract

Prepare for deployment

Step 1) Deploy XNFT.sol to Ethereum Sepolia

Step 2) Deploy XNFT.sol to Arbitrum Sepolia

Step 3) On Ethereum Sepolia, call enableChain function

Step 4) On Arbitrum Sepolia, call enableChain function

Step 5) On Arbitrum Sepolia, fund XNFT.sol with 3 LINK

Step 6) On Arbitrum Sepolia, mint new xNFT

Step 7) On Arbitrum Sepolia, crossTransferFrom xNFT

Option 2)

Option 2)