Automatic retry during onboarding, better UI while waiting

Tusker/Screens/Onboarding/OnboardingViewController.swift

@@ -9,12 +9,15 @@
 import UIKit
 import AuthenticationServices
 import Pachyderm
+import OSLog
 
 protocol OnboardingViewControllerDelegate {
     @MainActor
     func didFinishOnboarding(account: LocalData.UserAccountInfo)
 }
 
+private let logger = Logger(subsystem: Bundle.main.bundleIdentifier!, category: "OnboardingViewController")
+
 class OnboardingViewController: UINavigationController {
 
     var onboardingDelegate: OnboardingViewControllerDelegate?
@@ -40,7 +43,78 @@ class OnboardingViewController: UINavigationController {
     }
     
     @MainActor
-    private func tryLoginTo(instanceURL: URL) async throws {
+    private func login(to instanceURL: URL) async {
+        let dimmingView = UIView()
+        dimmingView.translatesAutoresizingMaskIntoConstraints = false
+        dimmingView.backgroundColor = .black.withAlphaComponent(0.1)
+        
+        let blur = UIBlurEffect(style: .prominent)
+        let blurView = UIVisualEffectView(effect: blur)
+        blurView.translatesAutoresizingMaskIntoConstraints = false
+        blurView.layer.cornerRadius = 15
+        blurView.layer.masksToBounds = true
+        
+        let spinner = UIActivityIndicatorView(style: .large)
+        spinner.translatesAutoresizingMaskIntoConstraints = false
+        spinner.startAnimating()
+        
+        let statusLabel = UILabel()
+        statusLabel.translatesAutoresizingMaskIntoConstraints = false
+        statusLabel.font = .preferredFont(forTextStyle: .headline)
+        statusLabel.numberOfLines = 0
+        statusLabel.textAlignment = .center
+        
+        blurView.contentView.addSubview(spinner)
+        blurView.contentView.addSubview(statusLabel)
+        dimmingView.addSubview(blurView)
+        view.addSubview(dimmingView)
+        NSLayoutConstraint.activate([
+            dimmingView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
+            dimmingView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
+            dimmingView.topAnchor.constraint(equalTo: view.topAnchor),
+            dimmingView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
+            
+            blurView.widthAnchor.constraint(equalToConstant: 150),
+            blurView.heightAnchor.constraint(equalToConstant: 150),
+            blurView.centerXAnchor.constraint(equalTo: view.safeAreaLayoutGuide.centerXAnchor),
+            blurView.centerYAnchor.constraint(equalTo: view.safeAreaLayoutGuide.centerYAnchor),
+            
+            spinner.centerXAnchor.constraint(equalTo: blurView.contentView.centerXAnchor),
+            spinner.bottomAnchor.constraint(equalTo: blurView.contentView.centerYAnchor, constant: -2),
+            statusLabel.leadingAnchor.constraint(equalTo: blurView.contentView.leadingAnchor),
+            statusLabel.trailingAnchor.constraint(equalTo: blurView.contentView.trailingAnchor),
+            statusLabel.topAnchor.constraint(equalTo: blurView.contentView.centerYAnchor, constant: 2),
+        ])
+        
+        dimmingView.layer.opacity = 0
+        blurView.transform = CGAffineTransform(scaleX: 1.2, y: 1.2)
+        UIView.animate(withDuration: 0.2, delay: 0, options: .curveEaseInOut) {
+            dimmingView.layer.opacity = 1
+            blurView.transform = .identity
+        }
+        
+        do {
+            try await tryLogin(to: instanceURL) {
+                statusLabel.text = $0
+            }
+        } catch Error.cancelled {
+            // no-op, don't show an error message
+        } catch {
+            let message: String
+            if let error = error as? Error {
+                message = error.localizedDescription
+            } else {
+                message = error.localizedDescription
+            }
+            let alert = UIAlertController(title: "Error Logging In", message: message, preferredStyle: .alert)
+            alert.addAction(UIAlertAction(title: "OK", style: .default))
+            self.present(alert, animated: true)
+        }
+        
+        dimmingView.removeFromSuperview()
+    }
+    
+    private func tryLogin(to instanceURL: URL, updateStatus: (String) -> Void) async throws {
         let mastodonController = MastodonController(instanceURL: instanceURL, transient: true)
         let clientID: String
         let clientSecret: String
@@ -48,28 +122,24 @@ class OnboardingViewController: UINavigationController {
             clientID = clientInfo.id
             clientSecret = clientInfo.secret
         } else {
+            updateStatus("Registering App")
             do {
                 (clientID, clientSecret) = try await mastodonController.registerApp()
                 self.clientInfo = (instanceURL, clientID, clientSecret)
-                // m.s has problems with (I think) the read replicas not updating fast enough
+                updateStatus("Reticulating Splines")
-                // so give it some more time to propagate, and prevent invalid_client/etc. errors
+                try await Task.sleep(nanoseconds: 500 * NSEC_PER_MSEC)
-                if instanceURL.host == "mastodon.social" {
-                    try await Task.sleep(nanoseconds: 2 * NSEC_PER_SEC)
-                }
             } catch {
                 throw Error.registeringApp(error)
             }
         }
+        updateStatus("Logging in")
         let authCode = try await getAuthorizationCode(instanceURL: instanceURL, clientID: clientID)
-                if instanceURL.host == "mastodon.social" {
+        updateStatus("Authorizing")
-                    try await Task.sleep(nanoseconds: 2 * NSEC_PER_SEC)
-                }
         let accessToken: String
         do {
-            accessToken = try await mastodonController.authorize(authorizationCode: authCode)
+            accessToken = try await retrying("Getting access token") {
-                if instanceURL.host == "mastodon.social" {
+                try await mastodonController.authorize(authorizationCode: authCode)
-                    try await Task.sleep(nanoseconds: 2 * NSEC_PER_SEC)
+            }
-                }
         } catch {
             throw Error.gettingAccessToken(error)
         }
@@ -78,9 +148,12 @@ class OnboardingViewController: UINavigationController {
         let tempAccountInfo = LocalData.UserAccountInfo(tempInstanceURL: instanceURL, clientID: clientID, clientSecret: clientSecret, accessToken: accessToken)
         mastodonController.accountInfo = tempAccountInfo
         
+        updateStatus("Checking Credentials")
         let ownAccount: Account
         do {
-            ownAccount = try await mastodonController.getOwnAccount()
+            ownAccount = try await retrying("Getting own account") {
+                try await mastodonController.getOwnAccount()
+            }
         } catch {
             throw Error.gettingOwnAccount(error)
         }
@@ -91,6 +164,19 @@ class OnboardingViewController: UINavigationController {
         self.onboardingDelegate?.didFinishOnboarding(account: accountInfo)
     }
     
+    private func retrying<T>(_ label: StaticString, action: () async throws -> T) async throws -> T {
+        for attempt in 0..<4 {
+            do {
+                return try await action()
+            } catch {
+                let seconds = (pow(2, attempt) as NSDecimalNumber).uint64Value
+                logger.error("\(label, privacy: .public) failed, waiting \(seconds, privacy: .public)s before retrying. Reason: \(String(describing: error))")
+                try! await Task.sleep(nanoseconds: seconds * NSEC_PER_SEC)
+            }
+        }
+        return try await action()
+    }
+    
     @MainActor
     private func getAuthorizationCode(instanceURL: URL, clientID: String) async throws -> String {
         var components = URLComponents(url: instanceURL, resolvingAgainstBaseURL: false)!
@@ -160,15 +246,8 @@ extension OnboardingViewController {
 extension OnboardingViewController: InstanceSelectorTableViewControllerDelegate {
     func didSelectInstance(url instanceURL: URL) {
         Task {
-            do {
+            await self.login(to: instanceURL)
-                try await self.tryLoginTo(instanceURL: instanceURL)
+            instanceSelector.tableView.selectRow(at: nil, animated: true, scrollPosition: .none)
-            } catch Error.cancelled {
-                // no-op, don't show an error message
-            } catch let error as Error {
-                let alert = UIAlertController(title: "Error Logging In", message: error.localizedDescription, preferredStyle: .alert)
-                alert.addAction(UIAlertAction(title: "OK", style: .default))
-                self.present(alert, animated: true)
-            }
         }
     }
 }