Simplify connecting sync accounts when two exist

Core/PixelEvent.swift

@@ -682,6 +682,13 @@ extension Pixel {
         case syncSecureStorageDecodingError
         case syncAccountRemoved(reason: String)
 
+        case syncAskUserToSwitchAccount
+        case syncUserAcceptedSwitchingAccount
+        case syncUserCancelledSwitchingAccount
+        case syncUserSwitchedAccount
+        case syncUserSwitchedLogoutError
+        case syncUserSwitchedLoginError
+
         case syncGetOtherDevices
         case syncGetOtherDevicesCopy
         case syncGetOtherDevicesShare
@@ -1620,6 +1627,13 @@ extension Pixel.Event {
         case .syncSecureStorageDecodingError: return "sync_secure_storage_decoding_error"
         case .syncAccountRemoved(let reason): return "sync_account_removed_reason_\(reason)"
 
+        case .syncAskUserToSwitchAccount: return "sync_ask_user_to_switch_account"
+        case .syncUserAcceptedSwitchingAccount: return "sync_user_accepted_switching_account"
+        case .syncUserCancelledSwitchingAccount: return "sync_user_cancelled_switching_account"
+        case .syncUserSwitchedAccount: return "sync_user_switched_account"
+        case .syncUserSwitchedLogoutError: return "sync_user_switched_logout_error"
+        case .syncUserSwitchedLoginError: return "sync_user_switched_login_error"
+
         case .syncGetOtherDevices: return "sync_get_other_devices"
         case .syncGetOtherDevicesCopy: return "sync_get_other_devices_copy"
         case .syncGetOtherDevicesShare: return "sync_get_other_devices_share"

DuckDuckGo/SyncSettingsViewController+SyncDelegate.swift

@@ -182,6 +182,47 @@ extension SyncSettingsViewController: SyncManagementViewModelDelegate {
         }
     }
 
+    @MainActor
+    func promptToSwitchAccounts(recoveryKey: SyncCode.RecoveryKey) {
+        let alertController = UIAlertController(
+            title: UserText.syncAlertSwitchAccountTitle,
+            message: UserText.syncAlertSwitchAccountMessage,
+            preferredStyle: .alert)
+        alertController.addAction(title: UserText.syncAlertSwitchAccountButton, style: .default) { [weak self] in
+            Task {
+                Pixel.fire(pixel: .syncUserAcceptedSwitchingAccount)
+                await self?.switchAccounts(recoveryKey: recoveryKey)
+            }
+        }
+        alertController.addAction(title: UserText.actionCancel, style: .cancel) {
+            Pixel.fire(pixel: .syncUserCancelledSwitchingAccount)
+        }
+        // Gives time to the is syncing view to appear
+        DispatchQueue.main.asyncAfter(deadline: .now() + 1) { [weak self] in
+            self?.dismissPresentedViewController { [weak self] in
+                self?.present(alertController, animated: true, completion: nil)
+                Pixel.fire(pixel: .syncAskUserToSwitchAccount)
+            }
+        }
+    }
+
+    func switchAccounts(recoveryKey: SyncCode.RecoveryKey) async {
+        Task { [weak self] in
+            do {
+                try await self?.syncService.disconnect()
+            } catch {
+                Pixel.fire(pixel: .syncUserSwitchedLogoutError)
+            }
+
+            do {
+                try await self?.loginAndShowDeviceConnected(recoveryKey: recoveryKey)
+            } catch {
+                Pixel.fire(pixel: .syncUserSwitchedLoginError)
+            }
+            Pixel.fire(pixel: .syncUserSwitchedAccount)
+        }
+    }
+
     private func getErrorType(from errorString: String?) -> AsyncErrorType? {
         guard let errorString = errorString else {
             return nil

DuckDuckGo/SyncSettingsViewController.swift

@@ -348,7 +348,7 @@
         }
     }
 
     func syncCodeEntered(code: String) async -> Bool {
         var shouldShowSyncEnabled = true
         guard let syncCode = try? SyncCode.decodeBase64String(code) else {
             return false
@@ -361,7 +361,11 @@
                 return true
             } catch {
                 if self.rootView.model.isSyncEnabled {
-                    handleError(.unableToMergeTwoAccounts, error: error, event: .syncLoginExistingAccountError)
+                    if rootView.model.devices.count > 1 {
+                        promptToSwitchAccounts(recoveryKey: recoveryKey)
+                    } else {
+                        await switchAccounts(recoveryKey: recoveryKey)
+                    }
                 } else {
                     handleError(.unableToSyncToServer, error: error, event: .syncLoginError)
                 }

DuckDuckGo/UserText.swift

@@ -961,6 +961,9 @@ But if you *do* want a peek under the hood, you can find more information about
     static let unknownErrorTryAgainMessage = NSLocalizedString("error.unknown.try.again", value: "An unknown error has occurred", comment: "Generic error message on a dialog for when the cause is not known.")
     public static let syncPausedAlertOkButton = NSLocalizedString("alert.sync-paused-alert-ok-button", value: "OK", comment: "Confirmation button in alert")
     public static let syncPausedAlertLearnMoreButton = NSLocalizedString("alert.sync-paused-alert-learn-more-button", value: "Learn More", comment: "Learn more button in alert")
+    public static let syncAlertSwitchAccountTitle = NSLocalizedString("alert.sync-switch-account-title", value: "Switch to a different Sync?", comment: "Switch account title in alert")
+    public static let syncAlertSwitchAccountMessage = NSLocalizedString("alert.sync-switch-account-message", value: "This device is already synced, are you sure you want to sync it with a different back up or device? Switching won't remove any data already synced to this device.", comment: "Description for switching sync accounts when there's two")
+    public static let syncAlertSwitchAccountButton = NSLocalizedString("alert.sync-switch-account-button", value: "Switch Sync", comment: "Switch account button in alert")
     public static let syncErrorAlertTitle = NSLocalizedString("alert.sync-error", value: "Sync & Backup Error", comment: "Title for sync error alert")
     public static let unableToSyncToServerDescription = NSLocalizedString("alert.unable-to-sync-to-server-description", value: "Unable to connect to the server.", comment: "Description for unable to sync to server error")
     public static let unableToSyncWithOtherDeviceDescription = NSLocalizedString("alert.unable-to-sync-with-other-device-description", value: "Unable to Sync with another device.", comment: "Description for unable to sync with another device error")

DuckDuckGo/en.lproj/Localizable.strings

@@ -200,6 +200,15 @@
 /* Title for alert shown when sync paused for an error */
 "alert.sync-paused-title" = "Sync is Paused";
 
+/* Switch account button in alert */
+"alert.sync-switch-account-button" = "Switch Sync";
+
+/* Description for switching sync accounts when there's two */
+"alert.sync-switch-account-message" = "This device is already synced, are you sure you want to sync it with a different back up or device? Switching won't remove any data already synced to this device.";
+
+/* Switch account title in alert */
+"alert.sync-switch-account-title" = "Switch to a different Sync?";
+
 /* Description for alert shown when sync error occurs because of too many requests */
 "alert.sync-too-many-requests-error-description" = "Sync & Backup is temporarily unavailable.";