Update domain selector view conditional logic with a state enum in the view model.

Author: jaclync

WooCommerce/Classes/ViewRelated/Dashboard/Settings/Domains/DomainSelectorView.swift

@@ -45,6 +45,18 @@ private extension DomainSelectorHostingController {
 
 /// Allows the user to search for a domain and then select one to continue.
 struct DomainSelectorView: View {
+    /// The state of the main view below the fixed header.
+    enum ViewState: Equatable {
+        /// When loading domain suggestions.
+        case loading
+        /// Shown when the search query is empty.
+        case placeholder
+        /// When there is an error loading domain suggestions.
+        case error(message: String)
+        /// When domain suggestions are displayed.
+        case results(domains: [String])
+    }
+
     /// Set in the hosting controller.
     var onDomainSelection: ((String) async -> Void) = { _ in }
 
@@ -87,7 +99,8 @@ struct DomainSelectorView: View {
                                                    iconSize: .init(width: 14, height: 14)))
                 .focused($textFieldIsFocused)
 
-                if viewModel.searchTerm.isEmpty {
+                switch viewModel.state {
+                case .placeholder:
                     // Placeholder image when search query is empty.
                     Spacer()
                         .frame(height: 30)
@@ -97,7 +110,7 @@ struct DomainSelectorView: View {
                         Image(uiImage: .domainSearchPlaceholderImage)
                         Spacer()
                     }
-                } else if viewModel.isLoadingDomainSuggestions {
+                case .loading:
                     // Progress indicator when loading domain suggestions.
                     Spacer()
                         .frame(height: 23)
@@ -107,7 +120,7 @@ struct DomainSelectorView: View {
                         ProgressView()
                         Spacer()
                     }
-                } else if let errorMessage = viewModel.errorMessage {
+                case .error(let errorMessage):
                     // Error message when there is an error loading domain suggestions.
                     Spacer()
                         .frame(height: 23)
@@ -118,7 +131,7 @@ struct DomainSelectorView: View {
                         .frame(maxWidth: .infinity, alignment: .center)
                         .multilineTextAlignment(.center)
                         .padding(Layout.defaultPadding)
-                } else {
+                case .results(let domains):
                     // Domain suggestions.
                     Text(Localization.suggestionsHeader)
                         .foregroundColor(Color(.secondaryLabel))
@@ -127,7 +140,7 @@ struct DomainSelectorView: View {
                         .padding(.vertical, insets: .init(top: 14, leading: 0, bottom: 8, trailing: 0))
 
                     LazyVStack {
-                        ForEach(viewModel.domains, id: \.self) { domain in
+                        ForEach(domains, id: \.self) { domain in
                             Button {
                                 textFieldIsFocused = false
                                 selectedDomainName = domain

WooCommerce/Classes/ViewRelated/Dashboard/Settings/Domains/DomainSelectorViewModel.swift

@@ -10,14 +10,17 @@ final class DomainSelectorViewModel: ObservableObject {
     @Published var searchTerm: String = ""
 
     /// Domain names after domain suggestions are loaded remotely.
-    @Published private(set) var domains: [String] = []
+    @Published private var domains: [String] = []
 
     /// Error message from loading domain suggestions.
-    @Published private(set) var errorMessage: String?
+    @Published private var errorMessage: String?
 
     /// Whether domain suggestions are being loaded.
     @Published private(set) var isLoadingDomainSuggestions: Bool = false
 
+    /// The state of the main domain selector view based on the search query and loading state.
+    @Published private(set) var state: DomainSelectorView.ViewState = .placeholder
+
     /// Subscription for search query changes for domain search.
     private var searchQuerySubscription: AnyCancellable?
 
@@ -36,6 +39,8 @@ final class DomainSelectorViewModel: ObservableObject {
         // and thus the initial value isn't emitted in `observeDomainQuery` until setting the value afterward.
         observeDomainQuery()
         self.searchTerm = initialSearchTerm
+
+        configureState()
     }
 }
 
@@ -64,6 +69,22 @@ private extension DomainSelectorViewModel {
             }
     }
 
+    func configureState() {
+        Publishers.CombineLatest4($searchTerm, $isLoadingDomainSuggestions, $errorMessage, $domains)
+            .map { searchTerm, isLoadingDomainSuggestions, errorMessage, domains in
+                if searchTerm.isEmpty {
+                    return .placeholder
+                } else if isLoadingDomainSuggestions {
+                    return .loading
+                } else if let errorMessage {
+                    return .error(message: errorMessage)
+                } else {
+                    return .results(domains: domains)
+                }
+            }
+            .assign(to: &$state)
+    }
+
     @MainActor
     func loadFreeDomainSuggestions(query: String) async -> Result<[FreeDomainSuggestion], Error> {
         await withCheckedContinuation { continuation in

WooCommerce/WooCommerceTests/ViewModels/Domains/DomainSelectorViewModelTests.swift

@@ -24,49 +24,61 @@ final class DomainSelectorViewModelTests: XCTestCase {
     func test_DomainAction_is_not_dispatched_when_searchTerm_is_empty() {
         // Given
         stores.whenReceivingAction(ofType: DomainAction.self) { action in
+            // Then
             XCTFail("Unexpected action: \(action)")
         }
 
         // When
         viewModel.searchTerm = ""
         viewModel.searchTerm = ""
-
-        // Then
-        XCTAssertEqual(viewModel.domains, [])
-        XCTAssertTrue(stores.receivedActions.isEmpty)
     }
 
-    func test_domain_suggestions_success_returns_domain_rows_for_free_domains() {
-        // Given
-        mockDomainSuggestionsSuccess(suggestions: [
-            .init(name: "free.com", isFree: true),
-            .init(name: "paid.com", isFree: false)
-        ])
+    // MARK: - `isLoadingDomainSuggestions`
+
+    func test_isLoadingDomainSuggestions_is_toggled_when_loading_suggestions() {
+        var loadingValues: [Bool] = []
+        viewModel.$isLoadingDomainSuggestions.sink { value in
+            loadingValues.append(value)
+        }.store(in: &subscriptions)
+
+        mockDomainSuggestionsFailure(error: SampleError.first)
 
         // When
-        viewModel.searchTerm = "woo"
+        viewModel.searchTerm = "Woo"
 
         // Then
         waitUntil {
-            self.viewModel.domains.isNotEmpty
+            loadingValues == [false, true, false]
         }
-        XCTAssertEqual(viewModel.domains, ["free.com"])
     }
 
-    func test_domain_suggestions_failure_does_not_update_domain_rows() {
+    // MARK: - `state`
+
+    func test_state_is_placeholder_when_searchTerm_is_empty() {
+        // When
+        viewModel.searchTerm = ""
+
+        // Then
+        XCTAssertEqual(viewModel.state, .placeholder)
+    }
+
+    func test_state_is_results_with_free_domain_only_on_domain_suggestions_success() {
         // Given
-        mockDomainSuggestionsFailure(error: SampleError.first)
+        mockDomainSuggestionsSuccess(suggestions: [
+            .init(name: "free.com", isFree: true),
+            .init(name: "paid.com", isFree: false)
+        ])
 
         // When
         viewModel.searchTerm = "woo"
 
         // Then
-        XCTAssertEqual(viewModel.domains, [])
+        waitUntil {
+            self.viewModel.state == .results(domains: ["free.com"])
+        }
     }
 
-    // MARK: - `errorMessage`
-
-    func test_domain_suggestions_failure_with_non_DotcomError_sets_default_error_message() {
+    func test_state_is_errorMessage_with_default_error_message_when_failure_is_not_DotcomError() {
         // Given
         mockDomainSuggestionsFailure(error: SampleError.first)
 
@@ -75,12 +87,11 @@ final class DomainSelectorViewModelTests: XCTestCase {
 
         // Then
         waitUntil {
-            self.viewModel.errorMessage?.isNotEmpty == true
+            self.viewModel.state == .error(message: DomainSelectorViewModel.Localization.defaultErrorMessage)
         }
-        XCTAssertEqual(viewModel.errorMessage, DomainSelectorViewModel.Localization.defaultErrorMessage)
     }
 
-    func test_domain_suggestions_failure_with_DotcomError_unknown_error_sets_error_message() {
+    func test_state_is_errorMessage_with_DotcomError_message_when_failure_is_DotcomError() {
         // Given
         mockDomainSuggestionsFailure(error: DotcomError.unknown(code: "", message: "error message"))
 
@@ -89,46 +100,26 @@ final class DomainSelectorViewModelTests: XCTestCase {
 
         // Then
         waitUntil {
-            self.viewModel.errorMessage?.isNotEmpty == true
+            self.viewModel.state == .error(message: "error message")
         }
-        XCTAssertEqual(viewModel.errorMessage, "error message")
     }
 
-    func test_domain_suggestions_error_message_is_reset_when_loading_domain_suggestions() {
+    func test_state_is_updated_from_errorMessage_to_results_when_changing_search_term_after_failure() {
         // Given
         mockDomainSuggestionsFailure(error: SampleError.first)
 
         // When
         viewModel.searchTerm = "woo"
         waitUntil {
-            self.viewModel.errorMessage?.isNotEmpty == true
+            self.viewModel.state == .error(message: DomainSelectorViewModel.Localization.defaultErrorMessage)
         }
 
         mockDomainSuggestionsSuccess(suggestions: [])
         viewModel.searchTerm = "wooo"
 
         // Then
         waitUntil {
-            self.viewModel.errorMessage == nil
-        }
-    }
-
-    // MARK: `isLoadingDomainSuggestions`
-
-    func test_isLoadingDomainSuggestions_is_toggled_when_loading_suggestions() {
-        var loadingValues: [Bool] = []
-        viewModel.$isLoadingDomainSuggestions.sink { value in
-            loadingValues.append(value)
-        }.store(in: &subscriptions)
-
-        mockDomainSuggestionsFailure(error: SampleError.first)
-
-        // When
-        viewModel.searchTerm = "Woo"
-
-        // Then
-        waitUntil {
-            loadingValues == [false, true, false]
+            self.viewModel.state == .results(domains: [])
         }
     }
 }