Refactor app startup code - extracting services (#3859)

Task/Issue URL: https://app.asana.com/0/0/1208832732122404/f

**Description**:
- Extract service-related code from the app’s launching logic to improve
maintainability and clarity.
- Establish clear patterns for synchronizing crucial services, ensuring
consistent behavior during app lifecycle events.
- Design an intuitive API to simplify usage for developers interacting
with the app lifecycle code.

Author: jaceklyp

Core/PixelEvent.swift

@@ -962,7 +962,6 @@ extension Pixel {
         // MARK: Launch time
         case appDidFinishLaunchingTime(time: BucketAggregation)
         case appDidShowUITime(time: BucketAggregation)
-        case appDidBecomeActiveTime(time: BucketAggregation)
 
         // MARK: AI Chat
         case aiChatNoRemoteSettingsFound(settings: String)
@@ -1951,7 +1950,6 @@ extension Pixel.Event {
         // MARK: Launch time
         case .appDidFinishLaunchingTime(let time): return "m_debug_app-did-finish-launching-time-\(time)"
         case .appDidShowUITime(let time): return "m_debug_app-did-show-ui-time-\(time)"
-        case .appDidBecomeActiveTime(let time): return "m_debug_app-did-become-active-time-\(time)"
 
         // MARK: AI Chat
         case .aiChatNoRemoteSettingsFound(let settings):
@@ -1963,7 +1961,7 @@ extension Pixel.Event {
         case .openAIChatFromWidgetLockScreenComplication: return "m_aichat-widget-lock-screen-complication"
 
         // MARK: Lifecycle
-        case .appDidTransitionToUnexpectedState: return "m_debug_app-did-transition-to-unexpected-state-3"
+        case .appDidTransitionToUnexpectedState: return "m_debug_app-did-transition-to-unexpected-state-4"
 
         case .debugBreakageExperiment: return "m_debug_breakage_experiment_u"
 

Core/StatisticsLoader.swift

@@ -54,6 +54,10 @@ public class StatisticsLoader {
     }
 
     public func load(completion: @escaping Completion = {}) {
+        let completion = {
+            self.refreshAppRetentionAtb()
+            completion()
+        }
         if statisticsStore.hasInstallStatistics {
             completion()
             return

Core/UserDefaultsPropertyWrapper.swift

@@ -57,7 +57,6 @@ public struct UserDefaultsWrapper<T> {
         case daxLastShownContextualOnboardingDialogType = "com.duckduckgo.ios.daxLastShownContextualOnboardingDialogType"
 
         case notFoundCache = "com.duckduckgo.ios.favicons.notFoundCache"
-        case faviconSizeNeedsMigration = "com.duckduckgo.ios.favicons.sizeNeedsMigration"
         case faviconTabsCacheNeedsCleanup = "com.duckduckgo.ios.favicons.tabsCacheNeedsCleanup"
 
         case legacyCovidInfo = "com.duckduckgo.ios.home.covidInfo"

DuckDuckGo-iOS.xcodeproj/project.pbxproj

@@ -0,0 +1,39 @@
+//
+//  ATBAndVariantConfiguration.swift
+//  DuckDuckGo
+//
+//  Copyright © 2025 DuckDuckGo. All rights reserved.
+//
+//  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 Foundation
+import Core
+import BrowserServicesKit
+
+final class ATBAndVariantConfiguration {
+
+    lazy var variantManager = DefaultVariantManager()
+
+    func configure(onVariantAssigned: () -> Void) {
+        cleanUpATBAndAssignVariant(onVariantAssigned: onVariantAssigned)
+    }
+
+    private func cleanUpATBAndAssignVariant(onVariantAssigned: () -> Void) {
+        AtbAndVariantCleanup.cleanup()
+        variantManager.assignVariantIfNeeded { _ in
+            onVariantAssigned()
+        }
+    }
+
+}

DuckDuckGo/AppConfiguration/ATBAndVariantConfiguration.swift

@@ -0,0 +1,33 @@
+//
+//  ContentBlockingConfiguration.swift
+//  DuckDuckGo
+//
+//  Copyright © 2025 DuckDuckGo. All rights reserved.
+//
+//  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 Foundation
+import Core
+
+final class ContentBlockingConfiguration {
+
+    static func configure() {
+        ContentBlocking.shared.onCriticalError = {
+            NotificationCenter.default.post(name: .appDidEncounterUnrecoverableState, object: nil)
+        }
+        // Explicitly prepare ContentBlockingUpdating instance before Tabs are created
+        _ = ContentBlockingUpdating.shared
+    }
+
+}

DuckDuckGo/AppConfiguration/ContentBlockingConfiguration.swift

@@ -0,0 +1,44 @@
+//
+//  CrashHandlersConfiguration.swift
+//  DuckDuckGo
+//
+//  Copyright © 2025 DuckDuckGo. All rights reserved.
+//
+//  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 Foundation
+import Core
+import Crashes
+
+final class CrashHandlersConfiguration {
+
+    @UserDefaultsWrapper(key: .didCrashDuringCrashHandlersSetUp, defaultValue: false)
+    static var didCrashDuringCrashHandlersSetUp: Bool
+
+    static func setupCrashHandlers() {
+        if !didCrashDuringCrashHandlersSetUp {
+            didCrashDuringCrashHandlersSetUp = true
+            CrashLogMessageExtractor.setUp(swapCxaThrow: false)
+            didCrashDuringCrashHandlersSetUp = false
+        }
+    }
+
+    static func handleCrashDuringCrashHandlersSetup() {
+        if didCrashDuringCrashHandlersSetUp {
+            Pixel.fire(pixel: .crashOnCrashHandlersSetUp)
+            didCrashDuringCrashHandlersSetUp = false
+        }
+    }
+
+}

DuckDuckGo/AppConfiguration/CrashHandlersConfiguration.swift

@@ -0,0 +1,29 @@
+//
+//  HistoryManagerConfiguration.swift
+//  DuckDuckGo
+//
+//  Copyright © 2025 DuckDuckGo. All rights reserved.
+//
+//  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 Foundation
+
+final class HistoryManagerConfiguration {
+
+    func onVariantAssigned() {
+        // New users don't see the message
+        HistoryMessageManager().dismiss()
+    }
+
+}

DuckDuckGo/AppConfiguration/HistoryManagerConfiguration.swift

@@ -0,0 +1,37 @@
+//
+//  KeyboardConfiguration.swift
+//  DuckDuckGo
+//
+//  Copyright © 2025 DuckDuckGo. All rights reserved.
+//
+//  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
+
+struct KeyboardConfiguration {
+
+    static func configure() {
+#if targetEnvironment(simulator)
+        if ProcessInfo.processInfo.environment["UITESTING"] == "true" {
+            // Disable hardware keyboards.
+            let setHardwareLayout = NSSelectorFromString("setHardwareLayout:")
+            UITextInputMode.activeInputModes
+            // Filter `UIKeyboardInputMode`s.
+                .filter({ $0.responds(to: setHardwareLayout) })
+                .forEach { $0.perform(setHardwareLayout, with: nil) }
+        }
+#endif
+    }
+
+}

DuckDuckGo/AppConfiguration/KeyboardConfiguration.swift

@@ -0,0 +1,46 @@
+//
+//  OnboardingConfiguration.swift
+//  DuckDuckGo
+//
+//  Copyright © 2025 DuckDuckGo. All rights reserved.
+//
+//  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 Foundation
+import Core
+
+final class OnboardingConfiguration {
+
+    lazy var daxDialogs = DaxDialogs.shared
+
+    func migrate() {
+        // Hide Dax Dialogs if users already completed old onboarding.
+        DaxDialogsOnboardingMigrator().migrateFromOldToNewOboarding()
+    }
+
+    // assign it here, because "did become active" is already too late and "viewWillAppear"
+    // has already been called on the HomeViewController so won't show the home row CTA
+    func onVariantAssigned() {
+        let launchOptionsHandler = LaunchOptionsHandler()
+
+        // MARK: perform first time launch logic here
+        // If it's running UI Tests check if the onboarding should be in a completed state.
+        if launchOptionsHandler.isUITesting && launchOptionsHandler.isOnboardingCompleted {
+            daxDialogs.dismiss()
+        } else {
+            daxDialogs.primeForUse()
+        }
+    }
+
+}

DuckDuckGo/AppConfiguration/OnboardingConfiguration.swift

@@ -0,0 +1,119 @@
+//
+//  PersistentStoresConfiguration.swift
+//  DuckDuckGo
+//
+//  Copyright © 2025 DuckDuckGo. All rights reserved.
+//
+//  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 Foundation
+import Core
+import Persistence
+
+public extension NSNotification.Name {
+
+    static let databaseDidEncounterInsufficientDiskSpace = Notification.Name("com.duckduckgo.database.insufficient.disk.space")
+
+}
+
+final class PersistentStoresConfiguration {
+
+    let database = Database.shared
+    let bookmarksDatabase = BookmarksDatabase.make()
+    private let application: UIApplication
+    private let notificationCenter: NotificationCenter
+
+    init(application: UIApplication = .shared,
+         notificationCenter: NotificationCenter = .default) {
+        self.application = application
+        self.notificationCenter = notificationCenter
+    }
+
+    func configure() {
+        clearTemporaryDirectory()
+        loadAndMigrateDatabase()
+        loadAndMigrateBookmarksDatabase()
+    }
+
+    private func clearTemporaryDirectory() {
+        let tmp = FileManager.default.temporaryDirectory
+        do {
+            try FileManager.default.removeItem(at: tmp)
+        } catch {
+            Logger.general.error("Failed to delete tmp dir")
+        }
+    }
+
+    private func loadAndMigrateDatabase() {
+        database.loadStore { [application] context, error in
+            guard let context = context else {
+                let parameters = [PixelParameters.applicationState: "\(application.applicationState.rawValue)",
+                                  PixelParameters.dataAvailability: "\(application.isProtectedDataAvailable)"]
+                switch error {
+                case .none:
+                    fatalError("Could not create database stack: Unknown Error")
+                case .some(CoreDataDatabase.Error.containerLocationCouldNotBePrepared(let underlyingError)):
+                    Pixel.fire(pixel: .dbContainerInitializationError,
+                               error: underlyingError,
+                               withAdditionalParameters: parameters)
+                    Thread.sleep(forTimeInterval: 1)
+                    fatalError("Could not create database stack: \(underlyingError.localizedDescription)")
+                case .some(let error):
+                    Pixel.fire(pixel: .dbInitializationError,
+                               error: error,
+                               withAdditionalParameters: parameters)
+                    if error.isDiskFull {
+                        NotificationCenter.default.post(name: .databaseDidEncounterInsufficientDiskSpace, object: nil)
+                        return
+                    } else {
+                        Thread.sleep(forTimeInterval: 1)
+                        fatalError("Could not create database stack: \(error.localizedDescription)")
+                    }
+                }
+            }
+            DatabaseMigration.migrate(to: context)
+        }
+    }
+
+    private func loadAndMigrateBookmarksDatabase() {
+        switch BookmarksDatabaseSetup().loadStoreAndMigrate(bookmarksDatabase: bookmarksDatabase) {
+        case .success:
+            break
+        case .failure(let error):
+            Pixel.fire(pixel: .bookmarksCouldNotLoadDatabase,
+                       error: error)
+            if error.isDiskFull {
+                NotificationCenter.default.post(name: .databaseDidEncounterInsufficientDiskSpace, object: nil)
+            } else {
+                Thread.sleep(forTimeInterval: 1)
+                fatalError("Could not create database stack: \(error.localizedDescription)")
+            }
+        }
+    }
+
+}
+
+extension Error {
+
+    var isDiskFull: Bool {
+        let nsError = self as NSError
+        if let underlyingError = nsError.userInfo["NSUnderlyingError"] as? NSError, underlyingError.code == 13 {
+            return true
+        } else if nsError.userInfo["NSSQLiteErrorDomain"] as? Int == 13 {
+            return true
+        }
+        return false
+    }
+
+}