async void OnInsertContactClicked()
        {
            if (string.IsNullOrEmpty(Name))
            {
                dialogHelper.ShowMessageDialog("Name cannot be empty!");
                return;
            }

            if (string.IsNullOrEmpty(EmailID))
            {
                dialogHelper.ShowMessageDialog("Email ID cannot be empty!");
                return;
            }

            var resultInsert = await FirebaseServiceHelper.Instance.InsetContact(new Contact { Name = Name, EmailID = EmailID });

            if (resultInsert.Success)
            {
                RefreshContacts();
            }
            else
            {
                dialogHelper.ShowMessageDialog("Insert failed!");
            }
        }
        async void OnLoginClicked()
        {
            if (string.IsNullOrEmpty(EmailID))
            {
                dialogHelper.ShowMessageDialog("Email ID cannot be empty!");
                return;
            }

            if (!Utility.Utility.IsValidEmailID(EmailID))
            {
                dialogHelper.ShowMessageDialog("Invalid Email ID format!");
                return;
            }

            if (string.IsNullOrEmpty(Password))
            {
                dialogHelper.ShowMessageDialog("Password cannot be empty!");
                return;
            }

            var response = await FirebaseServiceHelper.Instance.Login(new Model.User {
                EmailID = EmailID, Password = Password
            });

            if (response.Success == false)
            {
                dialogHelper.ShowMessageDialog("Login failed.");
            }
            else if (response.Code == Utility.Code.EmailNotVerified)
            {
                dialogHelper.ShowMessageDialog("Email NOT Verified.");
            }
            else
            {
                navigationService.Navigate("Home", null);
                navigationService.ClearHistory();
            }
        }
        async void OnRegisterClicked()
        {
            if (string.IsNullOrEmpty(Username))
            {
                dialogHelper.ShowMessageDialog("Username cannot be empty!");
                return;
            }

            if (string.IsNullOrEmpty(EmailID))
            {
                dialogHelper.ShowMessageDialog("Email ID cannot be empty!");
                return;
            }

            if (!Utility.Utility.IsValidEmailID(EmailID))
            {
                dialogHelper.ShowMessageDialog("Invalid Email ID format!");
                return;
            }

            if (string.IsNullOrEmpty(Password))
            {
                dialogHelper.ShowMessageDialog("Password cannot be empty!");
                return;
            }

            if (string.IsNullOrEmpty(RetypePassword))
            {
                dialogHelper.ShowMessageDialog("Retype Password cannot be empty!");
                return;
            }

            if (!Password.Equals(RetypePassword, StringComparison.CurrentCulture))
            {
                dialogHelper.ShowMessageDialog("Password mismatch!");
                return;
            }

            Registering = true;
            bool result = await FirebaseServiceHelper.Instance.Register(new Model.User {
                EmailID = EmailID, Password = Password, Username = Username
            });

            Registering = false;

            if (result)
            {
                dialogHelper.ShowMessageDialog("Verification link sent to your email address. Please verify to activate your account.");
            }
        }