Introduce new configure interface with non-optional completion

Commit also includes several improvements:
- filtering out empty queueIds;
- depracation of old `configure` method;
- replace checking interactor existance with configuration one to ensure SDK is configured;
- improve error handling in TestingApp

MOB-2784

GliaWidgets/Public/Glia/Glia+StartEngagement.swift

@@ -18,7 +18,7 @@ extension Glia {
     ///   - `GliaError.engagementExists
     ///   - `GliaError.sdkIsNotConfigured`
     ///
-    /// - Important: Note, that `configure(with:queueID:visitorContext:)` must be called initially prior to this method,
+    /// - Important: Note, that `configure(with:uiConfig:assetsBuilder:completion:)` must be called initially prior to this method,
     /// because `GliaError.sdkIsNotConfigured` will occur otherwise.
     ///
     public func startEngagement(
@@ -28,7 +28,10 @@ extension Glia {
         features: Features = .all,
         sceneProvider: SceneProvider? = nil
     ) throws {
-        guard !queueIds.isEmpty else { throw GliaError.startingEngagementWithNoQueueIdsIsNotAllowed }
+        let trimmedQueueIds = queueIds
+            .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+            .filter { !$0.isEmpty }
+        guard !trimmedQueueIds.isEmpty else { throw GliaError.startingEngagementWithNoQueueIdsIsNotAllowed }
         guard engagement == .none else { throw GliaError.engagementExists }
         guard let configuration = self.configuration else { throw GliaError.sdkIsNotConfigured }
         if let engagement = environment.coreSdk.getCurrentEngagement(),
@@ -39,7 +42,7 @@ extension Glia {
         // Creates interactor instance
         let createdInteractor = setupInteractor(
             configuration: configuration,
-            queueIds: queueIds
+            queueIds: trimmedQueueIds
         )
 
         theme.chat.connect.queue.firstText = companyName(

GliaWidgets/Public/Glia/Glia.Deprecated.swift

@@ -2,7 +2,7 @@ import GliaCoreSDK
 
 extension Glia {
     /// Deprecated.
-    @available(*, unavailable, message: "Use configure(with:queueId:uiConfig:assetsBuilder:completion:) instead.")
+    @available(*, unavailable, message: "Use configure(with:uiConfig:assetsBuilder:completion:) instead.")
     public func configure(
         with configuration: Configuration,
         queueId: String,
@@ -184,6 +184,27 @@ extension Glia {
             sceneProvider: sceneProvider
         )
     }
+
+    /// Deprecated, use the `configure` method that provides a `Result` in its completion instead.
+    @available(*, deprecated, message: "Use the `configure` method that provides a `Result` in its completion instead.")
+    public func configure(
+        with configuration: Configuration,
+        uiConfig: RemoteConfiguration? = nil,
+        assetsBuilder: RemoteConfiguration.AssetsBuilder = .standard,
+        completion: (() -> Void)? = nil
+    ) throws {
+        try configure(
+            with: configuration,
+            uiConfig: uiConfig,
+            assetsBuilder: assetsBuilder
+        ) { result in
+            defer {
+                completion?()
+            }
+            guard case let .failure(error) = result else { return }
+            debugPrint("💥 Core SDK configuration is not valid. Unexpected error='\(error)'.")
+        }
+    }
 }
 
 extension Glia.Authentication {

GliaWidgets/Public/Glia/Glia.RemoteConfiguration.swift

@@ -18,7 +18,7 @@ extension Glia {
     ///   - `GliaError.engagementExists
     ///   - `GliaError.sdkIsNotConfigured`
     ///
-    /// - Important: Note, that `configure(with:queueID:visitorContext:)` must be called initially prior to this method,
+    /// - Important: Note, that `configure(with:uiConfig:assetsBuilder:completion:)` must be called initially prior to this method,
     /// because `GliaError.sdkIsNotConfigured` will occur otherwise.
     ///
     public func startEngagementWithConfig(

GliaWidgets/Public/Glia/Glia.swift

@@ -104,23 +104,25 @@ public class Glia {
     /// Setup SDK using specific engagement configuration without starting the engagement.
     /// - Parameters:
     ///   - configuration: Engagement configuration.
-    ///   - visitorContext: Visitor context.
     ///   - uiConfig: Remote UI configuration.
     ///   - assetsBuilder: Provides assets for remote configuration.
-    ///   - completion: Optional completion handler that will be fired once configuration is complete.
-    ///   Passing  `nil` will defer configuration. Passing closure will start configuration immediately.
+    ///   - completion: Completion handler that will be fired once configuration is complete.
     public func configure(
         with configuration: Configuration,
         uiConfig: RemoteConfiguration? = nil,
         assetsBuilder: RemoteConfiguration.AssetsBuilder = .standard,
-        completion: (() -> Void)? = nil
+        completion: @escaping (Result<Void, Error>) -> Void
     ) throws {
         guard environment.coreSdk.getCurrentEngagement() == nil else {
             throw GliaError.configuringDuringEngagementIsNotAllowed
         }
         self.uiConfig = uiConfig
         self.assetsBuilder = assetsBuilder
-        self.configuration = configuration
+        // `configuration` should be erased to avoid cases when integrators
+        // call `configure` and `startEngagement` asynchronously, and
+        // second-time configuration has not been complete, but `startEngagement`
+        // is fired and SDK has previous `configuration`.
+        self.configuration = nil
 
         self.callVisualizer.delegate = { action in
             switch action {
@@ -129,10 +131,15 @@ public class Glia {
             }
         }
 
-        // TODO: - Non-optional completion will be added in MOB-2784
-        do {
-            try environment.coreSDKConfigurator.configureWithConfiguration(configuration) { [weak self] in
-                guard let self else { return }
+        try environment.coreSDKConfigurator.configureWithConfiguration(configuration) { [weak self] result in
+            guard let self else { return }
+            switch result {
+            case .success:
+                // Storing `configuration` needs to be done once configuring SDK is complete
+                // Otherwise integrator can call `configure` and `startEngagement`
+                // asynchronously, without waiting configuration completion.
+                self.configuration = configuration
+
                 let getRemoteString = self.environment.coreSdk.localeProvider.getRemoteString
                 self.stringProviding = .init(getRemoteString: getRemoteString)
 
@@ -141,11 +148,11 @@ public class Glia {
                     self.setupInteractor(configuration: configuration)
                 }
 
-                completion?()
+                completion(.success(()))
+            case let .failure(error):
+                debugPrint("💥 Core SDK configuration is not valid. Unexpected error='\(error)'.")
+                completion(.failure(error))
             }
-        } catch {
-            self.configuration = nil
-            debugPrint("💥 Core SDK configuration is not valid. Unexpected error='\(error)'.")
         }
     }
 
@@ -208,11 +215,11 @@ public class Glia {
     /// - `GliaCoreSDK.ConfigurationError.invalidEnvironment`
     /// - `GliaError.sdkIsNotConfigured`
     ///
-    /// - Important: Note, that in case of engagement has not been started yet, `configure(with:queueID:visitorContext:)` must be called initially prior to this method,
+    /// - Important: Note, that in case of engagement has not been started yet, `configure(with:uiConfig:assetsBuilder:completion:)` must be called initially prior to this method,
     /// because `GliaError.sdkIsNotConfigured` will occur otherwise.
     ///
     public func fetchVisitorInfo(completion: @escaping (Result<GliaCore.VisitorInfo, Error>) -> Void) {
-        guard interactor != nil else {
+        guard configuration != nil else {
             completion(.failure(GliaError.sdkIsNotConfigured))
             return
         }
@@ -242,14 +249,14 @@ public class Glia {
     /// - `GliaCoreSDK.ConfigurationError.invalidEnvironment`
     /// - `GliaError.sdkIsNotConfigured`
     ///
-    /// - Important: Note, that in case of engagement has not been started yet, `configure(with:queueID:visitorContext:)` must be called initially prior to this method,
+    /// - Important: Note, that in case of engagement has not been started yet, `configure(with:uiConfig:assetsBuilder:completion:)` must be called initially prior to this method,
     /// because `GliaError.sdkIsNotConfigured` will occur otherwise.
     ///
     public func updateVisitorInfo(
         _ info: VisitorInfoUpdate,
         completion: @escaping (Result<Bool, Error>) -> Void
     ) {
-        guard interactor != nil else {
+        guard configuration != nil else {
             completion(.failure(GliaError.sdkIsNotConfigured))
             return
         }
@@ -263,7 +270,7 @@ public class Glia {
             rootCoordinator = nil
         }
 
-        guard interactor != nil else {
+        guard configuration != nil else {
             completion(.failure(GliaError.sdkIsNotConfigured))
             return
         }
@@ -278,10 +285,10 @@ public class Glia {
     /// It is also possible to monitor Queues changes with [subscribeForUpdates](x-source-tag://subscribeForUpdates) method.
     /// If the request is unsuccessful for any reason then the completion will have an Error.
     /// - Parameters:
-    ///   - completion: A callback that will return the Result struct with `Queue` list or `GliaCoreError`
+    ///   - completion: A callback that will return the Result struct with `Queue` list or `GliaCoreError`.
     ///
     public func listQueues(_ completion: @escaping (Result<[Queue], Error>) -> Void) {
-        guard interactor != nil else {
+        guard configuration != nil else {
             completion(.failure(GliaError.sdkIsNotConfigured))
             return
         }

GliaWidgets/Sources/CoreSDKClient/CoreSDKClient.Interface.swift

@@ -19,7 +19,7 @@ struct CoreSdkClient {
 
     typealias ConfigureWithConfiguration = (
         _ sdkConfiguration: Self.Salemove.Configuration,
-        _ completion: (() -> Void)?
+        _ completion: @escaping Self.ConfigureCompletion
     ) -> Void
     var configureWithConfiguration: ConfigureWithConfiguration
 
@@ -249,4 +249,5 @@ extension CoreSdkClient {
     typealias Cancellable = GliaCore.Cancellable
     typealias ReactiveSwift = GliaCoreDependency.ReactiveSwift
     typealias SendMessagePayload = GliaCoreSDK.SendMessagePayload
+    typealias ConfigureCompletion = GliaCoreSDK.GliaCore.ConfigureCompletion
 }

GliaWidgets/Sources/CoreSDKConfigurator/CoreSDKConfigurator.Interface.swift

@@ -2,7 +2,7 @@ import Foundation
 
 struct CoreSDKConfigurator {
     var configureWithInteractor: CoreSdkClient.ConfigureWithInteractor
-    var configureWithConfiguration: (Configuration, (() -> Void)?) throws -> Void
+    var configureWithConfiguration: (Configuration, @escaping (Result<Void, Error>) -> Void) throws -> Void
 }
 
 extension CoreSDKConfigurator {
@@ -16,9 +16,7 @@ extension CoreSDKConfigurator {
                     authorizingMethod: configuration.authorizationMethod.coreAuthorizationMethod,
                     pushNotifications: configuration.pushNotifications.coreSdk
                 )
-                coreSdk.configureWithConfiguration(sdkConfiguration) {
-                    completion?()
-                }
+                coreSdk.configureWithConfiguration(sdkConfiguration, completion)
             }
         )
     }

GliaWidgets/Sources/ViewController/Call/CallViewController.Mock.swift

@@ -86,7 +86,7 @@ extension CallViewController {
         let queueId = UUID.mock.uuidString
         var interactorEnv = Interactor.Environment.mock
         interactorEnv.coreSdk.configureWithConfiguration = { _, callback in
-            callback?()
+            callback(.success(()))
         }
         let interactor = Interactor.mock(
             queueId: queueId,

GliaWidgets/Sources/ViewController/Chat/ChatViewController.Mock.swift

@@ -199,7 +199,7 @@ extension ChatViewController {
         chatViewModelEnv.fetchChatHistory = { $0(.success([])) }
         var interEnv = Interactor.Environment.mock
         interEnv.coreSdk.configureWithConfiguration = { _, callback in
-            callback?()
+            callback(.success(()))
         }
         let interactor = Interactor.mock(environment: interEnv)
         let generateUUID = UUID.incrementing
@@ -540,7 +540,7 @@ extension ChatViewController {
         chatViewModelEnv.fetchChatHistory = { $0(.success(messages)) }
         var interEnv = Interactor.Environment.mock
         interEnv.coreSdk.configureWithConfiguration = { _, callback in
-            callback?()
+            callback(.success(()))
         }
         let interactor = Interactor.mock(environment: interEnv)
         let chatViewModel = ChatViewModel.mock(interactor: interactor, environment: chatViewModelEnv)

GliaWidgetsTests/Sources/ChatViewModel/ChatViewModelTests.swift

@@ -367,7 +367,7 @@ class ChatViewModelTests: XCTestCase {
         // we use the mocked one, which doesn't execute the completion,
         // `sendMessageWithAttachment` will not be executed.
         environment.coreSdk.configureWithConfiguration = { _, completion in
-            completion?()
+            completion(.success(()))
         }
 
         let viewModel: ChatViewModel = .mock(
@@ -595,7 +595,7 @@ class ChatViewModelTests: XCTestCase {
         let interactor = Interactor.failing
         interactor.environment.gcd.mainQueue.asyncIfNeeded = { $0() }
         interactor.environment.coreSdk.configureWithInteractor = { _ in }
-        interactor.environment.coreSdk.configureWithConfiguration = { _, callback in callback?() }
+        interactor.environment.coreSdk.configureWithConfiguration = { _, callback in callback(.success(())) }
         interactor.environment.coreSdk.sendMessagePreview = { _, _ in }
         interactor.environment.coreSdk.sendMessageWithMessagePayload = { _, completion in
             completion(.success(.mock(id: expectedMessageId)))
@@ -645,7 +645,7 @@ class ChatViewModelTests: XCTestCase {
         let interactor = Interactor.failing
         interactor.environment.gcd.mainQueue.asyncIfNeeded = { $0() }
         interactor.environment.coreSdk.configureWithInteractor = { _ in }
-        interactor.environment.coreSdk.configureWithConfiguration = { _, callback in callback?() }
+        interactor.environment.coreSdk.configureWithConfiguration = { _, callback in callback(.success(())) }
         interactor.environment.coreSdk.sendMessagePreview = { _, _ in }
         interactor.environment.coreSdk.sendMessageWithMessagePayload = { [weak viewModel] _, completion in
             // Deliver message via socket before REST API response.