chore: Adding Factory for empty and no-op States that can be used in …

…SwiftUI's previews.

Sources/Authenticator/Utilities/PreviewFactory.swift

@@ -0,0 +1,120 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import Amplify
+import Foundation
+
+/// A utility class meant to provide 
+public enum PreviewFactory {
+    public enum States {
+        /// Returns an empty and no-op ``SignInState``.
+        public static func signIn() -> SignInState {
+            return .init(credentials: .init())
+        }
+
+        /// Returns an empty and no-op ``ConfirmSignInWithCodeState``.
+        /// - Parameter deliveryDetails: The ``AuthCodeDeliveryDetails`` associated with this state
+        public static func confirmSignInWithCode(deliveryDetails: AuthCodeDeliveryDetails? = nil) -> ConfirmSignInWithCodeState {
+            return ConfirmSignInWithCodeState(
+                authenticatorState: .empty(with: .confirmSignInWithMFACode(deliveryDetails: deliveryDetails))
+            )
+        }
+
+        /// Returns an empty and no-op ``ConfirmSignInWithNewPasswordState``.
+        public static func confirmSignInWithNewPassword() -> ConfirmSignInWithNewPasswordState {
+            return .init(credentials: .init())
+        }
+
+        /// Returns an empty and no-op ``ContinueSignInWithMFASelectionState``.
+        /// - Parameter allowedMFATypes: The ``AllowedMFATypes`` associated with this state
+        public static func continueSignInWithMFASelection(allowedMFATypes: AllowedMFATypes) -> ContinueSignInWithMFASelectionState {
+            return .init(
+                authenticatorState: .empty,
+                allowedMFATypes: allowedMFATypes
+            )
+        }
+
+        /// Returns an empty and no-op ``ContinueSignInWithTOTPSetupState``.
+        /// - Parameter issuer: The issuer associated with this state
+        /// - Parameter totpSetupDetails: The ``TOTPSetupDetails`` associated with this state
+        public static func continueSignInWithTOTPSetup(
+            issuer: String? = nil,
+            totpSetupDetails: TOTPSetupDetails
+        ) -> ContinueSignInWithTOTPSetupState {
+            return .init(
+                authenticatorState: .empty,
+                issuer: issuer,
+                totpSetupDetails: totpSetupDetails
+            )
+        }
+
+        /// Returns an empty and no-op ``SignUpState``.
+        /// - Parameter signUpFields: The list of ``SignUpField``s associated with this state
+        public static func signUp(signUpFields: [SignUpField] = []) -> SignUpState {
+            let state = SignUpState(credentials: .init())
+            state.configure(with: signUpFields)
+            return state
+        }
+
+        /// Returns an empty and no-op ``ConfirmSignUpState``.
+        /// - Parameter deliveryDetails: The ``AuthCodeDeliveryDetails`` associated with this state
+        public static func confirmSignUp(deliveryDetails: AuthCodeDeliveryDetails? = nil) -> ConfirmSignUpState {
+            return .init(
+                authenticatorState: .empty(with: .confirmSignUp(deliveryDetails: deliveryDetails)),
+                credentials: .init()
+            )
+        }
+
+        /// Returns an empty and no-op ``ResetPasswordState``.
+        public static func resetPasword() -> ResetPasswordState {
+            return .init(credentials: .init())
+        }
+
+        /// Returns an empty and no-op ``ConfirmResetPasswordState``.
+        /// - Parameter deliveryDetails: The ``AuthCodeDeliveryDetails`` associated with this state
+        public static func confirmResetPassword(deliveryDetails: AuthCodeDeliveryDetails? = nil) -> ConfirmResetPasswordState {
+            return .init(
+                authenticatorState: .empty(with: .confirmResetPassword(deliveryDetails: deliveryDetails)),
+                credentials: .init()
+            )
+        }
+
+        /// Returns an empty and no-op ``VerifyUserState``.
+        /// - Parameter unverifiedFields: The list of ``AuthUserAttributeKey``s associated with this state
+        public static func verifyUser(unverifiedFields: [AuthUserAttributeKey] = []) -> VerifyUserState {
+            return .init(
+                authenticatorState: .empty(with: .verifyUser(attributes: unverifiedFields)),
+                credentials: .init()
+            )
+        }
+
+        /// Returns an empty and no-op ``ConfirmVerifyUserState``.
+        /// - Parameter userAttributeKey: The ``AuthUserAttributeKey`` associated with this state
+        /// - Parameter deliveryDetails: The ``AuthCodeDeliveryDetails`` associated with this state
+        public static func confirmVerifyUser(
+            userAttributeKey: AuthUserAttributeKey,
+            deliveryDetails: AuthCodeDeliveryDetails? = nil
+        ) -> ConfirmVerifyUserState {
+            return .init(
+                authenticatorState: .empty(
+                    with: .confirmVerifyUser(
+                        attribute: userAttributeKey,
+                        deliveryDetails: deliveryDetails
+                    )
+                ),
+                credentials: .init()
+            )
+        }
+    }
+}
+
+private extension AuthenticatorStateProtocol where Self == EmptyAuthenticatorState {
+    static func empty(with step: Step) -> AuthenticatorStateProtocol {
+        return EmptyAuthenticatorState(step: step)
+    }
+}
+