UserViewController.swift

// Copyright 2020 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import UIKit
import FirebaseAuth
import AuthenticationServices
import CryptoKit

classUserViewController:UIViewController,DataSourceProviderDelegate{
vardataSourceProvider:DataSourceProvider<User>!

varuserImage=UIImageView(systemImageName:"person.circle.fill", tintColor:.secondaryLabel)
vartableView:UITableView{ view as!UITableView}

privatevar_user:User?
varuser:User?{
get{ _user ??Auth.auth().currentUser }
set{ _user = newValue }
}

 /// Init allows for injecting a `User` instance during UI Testing
 /// - Parameter user: A Firebase User instance
init(_ user:User?=nil){
 super.init(nibName:nil, bundle:nil)
self.user = user
}

requiredinit?(coder:NSCoder){
fatalError("init(coder:) has not been implemented")
}

 // MARK: - UIViewController Life Cycle

overridefunc loadView(){
 view =UITableView(frame:.zero, style:.insetGrouped)
}

overridefunc viewDidLoad(){
 super.viewDidLoad()
configureNavigationBar()
}

overridefunc viewWillAppear(_ animated:Bool){
 super.viewWillAppear(animated)
configureDataSourceProvider()
updateUserImage()
}

 // MARK: - DataSourceProviderDelegate

func tableViewDidScroll(_ tableView:UITableView){
adjustUserImageAlpha(tableView.contentOffset.y)
}

func didSelectRowAt(_ indexPath:IndexPath, on tableView:UITableView){
letitem= dataSourceProvider.item(at: indexPath)

letactionName= item.isEditable ? item.detailTitle! : item.title!

guardlet action =UserAction(rawValue: actionName)else{
 // The row tapped has no affiliated action.
return
}

switch action {
case.signOut:
signCurrentUserOut()

case.link:
linkUserToOtherAuthProviders()

case.requestVerifyEmail:
requestVerifyEmail()

case.tokenRefresh:
refreshCurrentUserIDToken()

case.delete:
deleteCurrentUser()

case.updateEmail:
presentEditUserInfoController(for: item, to: updateUserEmail)

case.updateDisplayName:
presentEditUserInfoController(for: item, to: updateUserDisplayName)

case.updatePhotoURL:
presentEditUserInfoController(for: item, to: updatePhotoURL)

case.refreshUserInfo:
refreshUserInfo()
}
}

 // MARK: - Firebase 🔥

publicfunc signCurrentUserOut(){
try?Auth.auth().signOut()
updateUI()
}

publicfunc linkUserToOtherAuthProviders(){
guardlet user = user else{return}
letaccountLinkingController=AccountLinkingViewController(for: user)
letnavController=UINavigationController(rootViewController: accountLinkingController)
 navigationController?.present(navController, animated:true, completion:nil)
}

publicfunc requestVerifyEmail(){
 user?.sendEmailVerification{ error in
guard error ==nilelse{returnself.displayError(error)}
print("Verification email sent!")
}
}

publicfunc refreshCurrentUserIDToken(){
letforceRefresh=true
 user?.getIDTokenForcingRefresh(forceRefresh){ token, error in
guard error ==nilelse{returnself.displayError(error)}
iflet token = token {
print("New token: \(token)")
}
}
}

publicfunc refreshUserInfo(){
 user?.reload{ error in
iflet error = error {
print(error)
}
self.updateUI()
}
}

publicfunc updateUserDisplayName(to newDisplayName:String){
letchangeRequest= user?.createProfileChangeRequest()
 changeRequest?.displayName = newDisplayName
 changeRequest?.commitChanges{ error in
guard error ==nilelse{returnself.displayError(error)}
self.updateUI()
}
}

publicfunc updateUserEmail(to newEmail:String){
 user?.updateEmail(to: newEmail, completion:{ error in
guard error ==nilelse{returnself.displayError(error)}
self.updateUI()
})
}

publicfunc updatePhotoURL(to newPhotoURL:String){
guardlet newPhotoURL =URL(string: newPhotoURL)else{
print("Could not create new photo URL!")
return
}
letchangeRequest= user?.createProfileChangeRequest()
 changeRequest?.photoURL = newPhotoURL
 changeRequest?.commitChanges{ error in
guard error ==nilelse{returnself.displayError(error)}
self.updateUI()
}
}

 // MARK: - Sign in with Apple Token Revocation Flow

 // For Sign in with Apple
privatevarcurrentNonce:String?

 // [START token_revocation_deleteuser]
privatefunc deleteCurrentUser(){
do{
letnonce=tryCryptoUtils.randomNonceString()
 currentNonce = nonce
letappleIDProvider=ASAuthorizationAppleIDProvider()
letrequest= appleIDProvider.createRequest()
 request.requestedScopes =[.fullName,.email]
 request.nonce =CryptoUtils.sha256(nonce)

letauthorizationController=ASAuthorizationController(authorizationRequests:[request])
 authorizationController.delegate =self
 authorizationController.presentationContextProvider =self
 authorizationController.performRequests()
}catch{
 // In the unlikely case that nonce generation fails, show error view.
displayError(error)
}
}

 // [END token_revocation_deleteuser]

 // MARK: - Private Helpers

privatefunc configureNavigationBar(){
 navigationItem.title ="User"
guardlet navigationBar = navigationController?.navigationBar else{return}
 navigationBar.prefersLargeTitles =true
 navigationBar.titleTextAttributes =[.foregroundColor:UIColor.systemOrange]
 navigationBar.largeTitleTextAttributes =[.foregroundColor:UIColor.systemOrange]
 navigationBar.addProfilePic(userImage)
}

privatefunc updateUserImage(){
guardlet photoURL = user?.photoURL else{
letdefaultImage=UIImage(systemName:"person.circle.fill")
 userImage.image = defaultImage?.withTintColor(.secondaryLabel, renderingMode:.alwaysOriginal)
return
}
 userImage.setImage(from: photoURL)
}

privatefunc configureDataSourceProvider(){
 dataSourceProvider =DataSourceProvider(
 dataSource: user?.sections,
 emptyStateView:SignedOutView(),
 tableView: tableView
)
 dataSourceProvider.delegate =self
}

privatefunc updateUI(){
configureDataSourceProvider()
animateUpdates(for: tableView)
updateUserImage()
}

privatefunc animateUpdates(for tableView:UITableView){
UIView.transition(with: tableView, duration:0.2,
 options:.transitionCrossDissolve,
 animations:{ tableView.reloadData()})
}

privatefunc presentEditUserInfoController(for item:Itemable,
 to saveHandler:@escaping(String)->Void){
leteditController=UIAlertController(
 title:"Update \(item.detailTitle!)",
 message:nil,
 preferredStyle:.alert
)
 editController.addTextField{ $0.placeholder ="New \(item.detailTitle!)"}

letsaveHandler:(UIAlertAction)->Void={ _ in
lettext= editController.textFields!.first!.text!
saveHandler(text)
}

 editController.addAction(UIAlertAction(title:"Save", style:.default, handler: saveHandler))
 editController.addAction(UIAlertAction(title:"Cancel", style:.cancel))
present(editController, animated:true, completion:nil)
}

privatevaroriginalOffset:CGFloat?

privatefunc adjustUserImageAlpha(_ offset:CGFloat){
 originalOffset = originalOffset ?? offset
letverticalOffset= offset - originalOffset!
 userImage.alpha =1-(verticalOffset *0.05)
}
}

// MARK: - Implementing Sign in with Apple for the Token Revocation Flow

extensionUserViewController:ASAuthorizationControllerDelegate,
ASAuthorizationControllerPresentationContextProviding{
 // MARK: ASAuthorizationControllerDelegate

 // [START token_revocation]
func authorizationController(controller:ASAuthorizationController,
 didCompleteWithAuthorization authorization:ASAuthorization){
guardlet appleIDCredential = authorization.credential as?ASAuthorizationAppleIDCredential
else{
print("Unable to retrieve AppleIDCredential")
return
}

guardlet _ = currentNonce else{
fatalError("Invalid state: A login callback was received, but no login request was sent.")
}

guardlet appleAuthCode = appleIDCredential.authorizationCode else{
print("Unable to fetch authorization code")
return
}

guardlet authCodeString =String(data: appleAuthCode, encoding:.utf8)else{
print("Unable to serialize auth code string from data: \(appleAuthCode.debugDescription)")
return
}

Task{
do{
tryawaitAuth.auth().revokeToken(withAuthorizationCode: authCodeString)
tryawait user?.delete()
self.updateUI()
}catch{
self.displayError(error)
}
}
}

 // [END token_revocation]

func authorizationController(controller:ASAuthorizationController,
 didCompleteWithError error:Error){
 // Ensure that you have:
 // - enabled `Sign in with Apple` on the Firebase console
 // - added the `Sign in with Apple` capability for this project
print("Sign in with Apple failed: \(error)")
}

 // MARK: ASAuthorizationControllerPresentationContextProviding

func presentationAnchor(for controller:ASAuthorizationController)->ASPresentationAnchor{
return view.window!
}
}