Replace native WP.com sign in with web-based sign in (#23675)

* Consolidate tracking of web-based WP.com login

* Add a clousre to overwrite handling of the WP.com login button

* Replace native WP.com sign in with web-based sign in

* Add a release note

* Extract error alert into a function

* Handle a scenario where users deny access on web login

* Disable web log for UI tests

Author: crazytonyli

RELEASE-NOTES.txt

@@ -4,7 +4,7 @@
 
 25.5
 -----
-
+* [***] Use web-based sign-in flow (hidden under a feature flag) [#23675]
 
 25.4
 -----

WordPress/Classes/Login/WordPressDotComAuthenticator.swift

@@ -1,6 +1,7 @@
 import AuthenticationServices
 import Foundation
 import UIKit
+import WordPressAuthenticator
 
 import Alamofire
 
@@ -10,14 +11,84 @@ import Alamofire
 struct WordPressDotComAuthenticator {
     enum Error: Swift.Error {
         case invalidCallbackURL
+        case loginDenied(message: String)
         case obtainAccessToken
         case urlError(URLError)
         case parsing(DecodingError)
         case cancelled
         case unknown(Swift.Error)
     }
 
+    @MainActor
+    func signIn(from viewController: UINavigationController) async {
+        let token: String
+        do {
+            token = try await authenticate(from: viewController)
+        } catch {
+            if let error = error as? WordPressDotComAuthenticator.Error {
+                presentSignInError(error, from: viewController)
+            } else {
+                wpAssertionFailure("WP.com web login failed", userInfo: ["error": "\(error)"])
+            }
+            return
+        }
+
+        let delegate = WordPressAuthenticator.shared.delegate!
+        let credentials = AuthenticatorCredentials(wpcom: WordPressComCredentials(authToken: token, isJetpackLogin: false, multifactor: false))
+        SVProgressHUD.show()
+        delegate.sync(credentials: credentials) {
+            SVProgressHUD.dismiss()
+
+            delegate.presentLoginEpilogue(
+                in: viewController,
+                for: credentials,
+                source: .custom(source: "web-login"),
+                onDismiss: { /* Do nothing */ }
+            )
+        }
+    }
+
+    private func presentSignInError(_ error: WordPressDotComAuthenticator.Error, from viewController: UIViewController) {
+        // Show an alert for non-cancellation errors.
+        let alertMessage: String
+        switch error {
+        case .cancelled:
+            // `.cancelled` error is thrown when user taps the cancel button in the presented Safari view controller.
+            // No need to show an alert for this error.
+            return
+        case let .loginDenied(message):
+            alertMessage = message
+        case let .urlError(error):
+            alertMessage = error.localizedDescription
+        case .invalidCallbackURL, .obtainAccessToken, .parsing, .unknown:
+            // These errors are unexpected.
+            wpAssertionFailure("WP.com web login failed", userInfo: ["error": "\(error)"])
+            alertMessage = SharedStrings.Error.generic
+        }
+
+        let alert = UIAlertController(
+            title: NSLocalizedString("generic.error.title", value: "Error", comment: "A generic title for an error"),
+            message: alertMessage,
+            preferredStyle: .alert
+        )
+        alert.addAction(UIAlertAction(title: SharedStrings.Button.close, style: .cancel, handler: nil))
+        viewController.present(alert, animated: true)
+    }
+
     func authenticate(from viewController: UIViewController) async throws -> String {
+        WPAnalytics.track(.wpcomWebSignIn, properties: ["stage": "start"])
+
+        do {
+            let value = try await _authenticate(from: viewController)
+            WPAnalytics.track(.wpcomWebSignIn, properties: ["stage": "success"])
+            return value
+        } catch {
+            WPAnalytics.track(.wpcomWebSignIn, properties: ["stage": "error", "error": "\(error)"])
+            throw error
+        }
+    }
+
+    private func _authenticate(from viewController: UIViewController) async throws -> String {
         let clientId = ApiCredentials.client
         let clientSecret = ApiCredentials.secret
         let redirectURI = "x-wordpress-app://oauth2-callback"
@@ -55,8 +126,17 @@ struct WordPressDotComAuthenticator {
         clientSecret: String,
         redirectURI: String
     ) async throws -> String {
-        guard let query = URLComponents(url: url, resolvingAgainstBaseURL: true)?.queryItems,
-              let code = query.first(where: { $0.name == "code" })?.value else {
+        guard let query = URLComponents(url: url, resolvingAgainstBaseURL: true)?.queryItems else {
+            throw Error.invalidCallbackURL
+        }
+
+        let queryMap: [String: String] = query.reduce(into: [:]) { $0[$1.name] = $1.value }
+
+        guard let code = queryMap["code"] else {
+            if queryMap["error"] == "access_denied" {
+                let message = NSLocalizedString("wpComLogin.error.accessDenied", value: "Access denied. You need to approve to log in to WordPress.com", comment: "Error message when user denies access to WordPress.com")
+                throw Error.loginDenied(message: message)
+            }
             throw Error.invalidCallbackURL
         }
 

WordPress/Classes/System/Root View/SplitViewRootPresenter.swift

@@ -181,18 +181,13 @@ final class SplitViewRootPresenter: RootViewPresenter {
     }
 
     @MainActor private func signIn() async {
-        WPAnalytics.track(.wpcomWebSignIn, properties: ["source": "sidebar", "stage": "start"])
-
         let token: String
         do {
             token = try await WordPressDotComAuthenticator().authenticate(from: splitVC)
         } catch {
-            WPAnalytics.track(.wpcomWebSignIn, properties: ["source": "sidebar", "stage": "error", "error": "\(error)"])
             return
         }
 
-        WPAnalytics.track(.wpcomWebSignIn, properties: ["source": "sidebar", "stage": "success"])
-
         SVProgressHUD.show()
         let credentials = WordPressComCredentials(authToken: token, isJetpackLogin: false, multifactor: false)
         WordPressAuthenticator.shared.delegate!.sync(credentials: .init(wpcom: credentials)) {

WordPress/Classes/System/Root View/WordPressAuthenticatorProtocol.swift

@@ -8,6 +8,34 @@ protocol WordPressAuthenticatorProtocol {
 
 extension WordPressAuthenticator: WordPressAuthenticatorProtocol {
     static func loginUI() -> UIViewController? {
-        Self.loginUI(showCancel: false, restrictToWPCom: false, onLoginButtonTapped: nil)
+        Self.loginUI(showCancel: false, restrictToWPCom: false, onLoginButtonTapped: nil, continueWithDotCom: { viewController in
+            guard Self.dotComWebLoginEnabled, let navigationController = viewController.navigationController else {
+                return false
+            }
+
+            Task { @MainActor in
+                await WordPressDotComAuthenticator().signIn(from: navigationController)
+            }
+
+            return true
+        })
+    }
+
+    static var dotComWebLoginEnabled: Bool {
+        // Some UI tests go through the native login flow. They should be updated once the web sign in flow is fully
+        // rolled out. We'll disable web login for UI tests for now.
+        if UITestConfigurator.isUITesting() {
+            return false
+        }
+
+        // TODO: Replce with a remote feature flag.
+        // Enable web-based login for debug builds until the remote feature flag is available.
+        #if DEBUG
+        let webLoginEnabled = true
+        #else
+        let webLoginEnabled = false
+        #endif
+
+        return webLoginEnabled
     }
 }

WordPress/Classes/System/UITesting/UITestConfigurator.swift

@@ -1,6 +1,10 @@
 import Foundation
 
 struct UITestConfigurator {
+    static func isUITesting() -> Bool {
+        CommandLine.arguments.contains("-ui-testing")
+    }
+
     static func prepareApplicationForUITests(in app: UIApplication, window: UIWindow) {
         let arguments = CommandLine.arguments
         if arguments.contains("-ui-testing") {

WordPress/Classes/ViewRelated/Me/Me Main/MeViewController.swift

@@ -525,18 +525,13 @@ class MeViewController: UITableViewController {
     ///
     fileprivate func promptForLoginOrSignup() {
         Task { @MainActor in
-            WPAnalytics.track(.wpcomWebSignIn, properties: ["source": "me", "stage": "start"])
-
             let token: String
             do {
                 token = try await WordPressDotComAuthenticator().authenticate(from: self)
             } catch {
-                WPAnalytics.track(.wpcomWebSignIn, properties: ["source": "me", "stage": "error", "error": "\(error)"])
                 return
             }
 
-            WPAnalytics.track(.wpcomWebSignIn, properties: ["source": "me", "stage": "success"])
-
             SVProgressHUD.show()
             let credentials = WordPressComCredentials(authToken: token, isJetpackLogin: false, multifactor: false)
             WordPressAuthenticator.shared.delegate!.sync(credentials: .init(wpcom: credentials)) {

WordPressAuthenticator/Sources/Authenticator/WordPressAuthenticator.swift

@@ -165,7 +165,7 @@ import WordPressKit
     ///   - restrictToWPCom: Whether only WordPress.com login is enabled.
     ///   - onLoginButtonTapped: Called when the login button on the prologue screen is tapped.
     /// - Returns: The root view controller for the login flow.
-    public class func loginUI(showCancel: Bool = false, restrictToWPCom: Bool = false, onLoginButtonTapped: (() -> Void)? = nil) -> UIViewController? {
+    public class func loginUI(showCancel: Bool = false, restrictToWPCom: Bool = false, onLoginButtonTapped: (() -> Void)? = nil, continueWithDotCom: ((UIViewController) -> Bool)? = nil) -> UIViewController? {
         let storyboard = Storyboard.login.instance
         guard let controller = storyboard.instantiateInitialViewController() else {
             assertionFailure("Cannot instantiate initial login controller from Login.storyboard")
@@ -174,6 +174,7 @@ import WordPressKit
 
         if let loginNavController = controller as? LoginNavigationController, let loginPrologueViewController = loginNavController.viewControllers.first as? LoginPrologueViewController {
             loginPrologueViewController.showCancel = showCancel
+            loginPrologueViewController.continueWithDotComOverwrite = continueWithDotCom
         }
 
         controller.modalPresentationStyle = .fullScreen

WordPressAuthenticator/Sources/Signin/LoginPrologueViewController.swift

@@ -11,6 +11,7 @@ class LoginPrologueViewController: LoginViewController {
     private var buttonViewController: NUXButtonViewController?
     private var stackedButtonsViewController: NUXStackedButtonsViewController?
     var showCancel = false
+    var continueWithDotComOverwrite: ((UIViewController) -> Bool)? = nil
 
     @IBOutlet private weak var buttonContainerView: UIView!
     /// Blur effect on button container view
@@ -526,6 +527,10 @@ class LoginPrologueViewController: LoginViewController {
     /// Unified "Continue with WordPress.com" prologue button action.
     ///
     private func continueWithDotCom() {
+        if let continueWithDotComOverwrite, continueWithDotComOverwrite(self) {
+            return
+        }
+
         guard let vc = GetStartedViewController.instantiate(from: .getStarted) else {
             WPAuthenticatorLogError("Failed to navigate from LoginPrologueViewController to GetStartedViewController")
             return