SIWE plus text username

import UIKit
import EthereumKit

class SignupViewController: UIViewController {

    // MARK: - Properties

    let ethereumClient = EthereumClient()

    // MARK: - View Lifecycle

    override func viewDidLoad() {
        super.viewDidLoad()

        // Generate a new Ethereum address
        let newAddress = ethereumClient.createAddress()

        // Generate a private recovery key for the Ethereum address
        let privateRecoveryKey = ethereumClient.createPrivateRecoveryKey(from: newAddress)

        // Show the private recovery key to the user
        let recoveryKeyLabel = UILabel()
        recoveryKeyLabel.text = "Private Recovery Key: \(privateRecoveryKey)"
        view.addSubview(recoveryKeyLabel)

        // Prompt the user to write down their private recovery key
        let recoveryKeyPromptLabel = UILabel()
        recoveryKeyPromptLabel.text = "Please write down your private recovery key on a piece of paper and store it safely. This is the ONLY way to recover your blockchain rewards."
        view.addSubview(recoveryKeyPromptLabel)

        // Set up a text field for the user to enter their in-app username
        let usernameTextField = UITextField()
        usernameTextField.placeholder = "Username"
        view.addSubview(usernameTextField)

        // Set up a button to confirm the user's in-app username
        let confirmButton = UIButton(type: .system)
        confirmButton.setTitle("Confirm", for: .normal)
        confirmButton.addTarget(self, action: #selector(confirmButtonTapped), for: .touchUpInside)
        view.addSubview(confirmButton)
    }

    // MARK: - Actions

    @objc
    func confirmButtonTapped() {
        // Get the user's in-app username from the text field
        let username = usernameTextField.text

        // Associate the user's Ethereum address with their in-app username
        ethereumClient.setUsername(username, for: newAddress)

        // Proceed to the next screen in the app
    }
}