@IBOutlet weak var usernameField: UITextField!
    @IBOutlet weak var passwordField: UITextField!


    @IBOutlet weak var usernameErrorMessage: UILabel!
    @IBOutlet weak var passwordErrorMessage: UILabel!


    @IBOutlet weak var loginMessage: UILabel!

    @IBAction func loginPressed(_ sender: Any) {
        var username = usernameField.text ?? ""
        var password = passwordField.text ?? ""

        var validUsername = true
        var validPassword = true

        loginMessage.isHidden = true


        if username.characters.count < 4 {
            if username.isEmpty {
                usernameErrorMessage.text = "Username cannot be empty"
            } else {
                usernameErrorMessage.text = "Username too short"
            }


            usernameErrorMessage.isHidden = false
            validUsername = false
        } else {
            usernameErrorMessage.isHidden = true
        }

        if password.characters.count < 7 {
            if password.isEmpty {
                passwordErrorMessage.text = "Password cannot be empty"
            } else {
                passwordErrorMessage.text = "Password too short"
            }


            passwordErrorMessage.isHidden = false
            validPassword = false
        } else {
            passwordErrorMessage.isHidden = true
        }

        if validUsername && validPassword {

            if (username == "admin" && password == "password") {
                loginMessage.text = "Login success!"
                loginMessage.textColor = UIColor.green
            } else {
                loginMessage.text = "Invalid username or password!"
                loginMessage.textColor = UIColor.red
            }


            loginMessage.isHidden = false
        }
    }