fix: Improve preloading robustness

ios/Sources/GutenbergKit/Sources/EditorViewController.swift

@@ -281,7 +281,6 @@ public final class EditorViewController: UIViewController, GutenbergEditorContro
     @MainActor
     private func loadEditor(dependencies: EditorDependencies) throws {
         self.displayActivityView()
-        defer { self.hideActivityView() }
 
         // Set asset bundle for the URL scheme handler to serve cached plugin/theme assets
         self.bundleProvider.set(bundle: dependencies.assetBundle)
@@ -676,6 +675,7 @@ public final class EditorViewController: UIViewController, GutenbergEditorContro
             return
         }
 
+        self.hideActivityView()
         self.isReady = true
 
         // Fade in the WebView - it was hidden (alpha = 0) since viewDidLoad()

ios/Sources/GutenbergKit/Sources/Model/EditorAssetBundle.swift

@@ -76,9 +76,17 @@ public struct EditorAssetBundle: Sendable, Equatable, Hashable {
     /// Loads a bundle from a JSON file on disk.
     ///
     /// - Parameter url: The file URL of the bundle's `manifest.json`.
-    /// - Throws: An error if the file cannot be read or decoded.
+    /// - Throws: An error if the file cannot be read or decoded, or if required files are missing.
     init(url: URL) throws {
-        self = try EditorAssetBundle(data:  Data(contentsOf: url), bundleRoot: url.deletingLastPathComponent())
+        let bundleRoot = url.deletingLastPathComponent()
+
+        // Validate that editor-representation.json exists (required for the bundle to be usable)
+        let editorRepPath = bundleRoot.appending(path: "editor-representation.json")
+        guard FileManager.default.fileExists(atPath: editorRepPath.path) else {
+            throw CocoaError(.fileNoSuchFile, userInfo: [NSFilePathErrorKey: editorRepPath.path])
+        }
+
+        self = try EditorAssetBundle(data: Data(contentsOf: url), bundleRoot: bundleRoot)
     }
 
     init(data: Data, bundleRoot: URL) throws {
@@ -163,10 +171,14 @@ public struct EditorAssetBundle: Sendable, Equatable, Hashable {
     ///
     /// - Parameter path: The file URL where the bundle should be saved.
     /// - Throws: An error if encoding fails or the file cannot be written.
-    func writeManifest(to path: URL? = nil) throws {
+    func writeManifest(to path: URL? = nil, editorRepresentation: EditorRepresentation? = nil) throws {
         try FileManager.default.createDirectory(at: self.bundleRoot, withIntermediateDirectories: true)
         let destination = path ?? self.bundleRoot.appendingPathComponent("manifest.json")
         try self.dataRepresentation().write(to: destination, options: .atomic)
+
+        if let editorRepresentation {
+            try setEditorRepresentation(editorRepresentation)
+        }
     }
 
     /// Copies the bundle to the given directoy.

ios/Sources/GutenbergKit/Sources/RESTAPIRepository.swift

@@ -30,10 +30,62 @@ public struct RESTAPIRepository: Sendable {
 
         let apiRoot = configuration.siteApiRoot
 
-        self.editorSettingsUrl = apiRoot.appending(rawPath: Constants.API.editorSettingsPath)
-        self.activeThemeUrl = apiRoot.appending(rawPath: Constants.API.activeThemePath)
-        self.siteSettingsUrl = apiRoot.appending(rawPath: Constants.API.siteSettingsPath)
-        self.postTypesUrl = apiRoot.appending(rawPath: Constants.API.postTypesPath)
+        // Use custom endpoint if provided, otherwise build from apiRoot with namespace
+        if let customEndpoint = configuration.editorSettingsEndpoint {
+            self.editorSettingsUrl = customEndpoint
+        } else {
+            self.editorSettingsUrl = Self.buildNamespacedURL(
+                apiRoot: apiRoot,
+                path: Constants.API.editorSettingsPath,
+                namespace: configuration.siteApiNamespace.first
+            )
+        }
+
+        self.activeThemeUrl = Self.buildNamespacedURL(
+            apiRoot: apiRoot,
+            path: Constants.API.activeThemePath,
+            namespace: configuration.siteApiNamespace.first
+        )
+        self.siteSettingsUrl = Self.buildNamespacedURL(
+            apiRoot: apiRoot,
+            path: Constants.API.siteSettingsPath,
+            namespace: configuration.siteApiNamespace.first
+        )
+        self.postTypesUrl = Self.buildNamespacedURL(
+            apiRoot: apiRoot,
+            path: Constants.API.postTypesPath,
+            namespace: configuration.siteApiNamespace.first
+        )
+    }
+
+    /// Builds a URL by inserting the namespace after the version segment of the path.
+    /// For example: `/wp/v2/posts` with namespace `sites/123/` becomes `/wp/v2/sites/123/posts`
+    private static func buildNamespacedURL(apiRoot: URL, path: String, namespace: String?) -> URL {
+        guard let namespace = namespace else {
+            return apiRoot.appending(rawPath: path)
+        }
+
+        // Parse the path to find where to insert the namespace
+        // Path format is typically: /prefix/version/endpoint (e.g., /wp/v2/posts or /wp-block-editor/v1/settings)
+        let components = path.split(separator: "/", omittingEmptySubsequences: true)
+        guard components.count >= 2 else {
+            return apiRoot.appending(rawPath: path)
+        }
+
+        // Insert namespace after the version segment (second component)
+        // e.g., /wp-block-editor/v1/settings -> /wp-block-editor/v1/sites/123/settings
+        let prefix = components[0]
+        let version = components[1]
+        let remainder = components.dropFirst(2).joined(separator: "/")
+
+        let namespacedPath: String
+        if remainder.isEmpty {
+            namespacedPath = "/\(prefix)/\(version)/\(namespace)"
+        } else {
+            namespacedPath = "/\(prefix)/\(version)/\(namespace)\(remainder)"
+        }
+
+        return apiRoot.appending(rawPath: namespacedPath)
     }
 
     /// Clears all cached API responses.
@@ -54,12 +106,13 @@ public struct RESTAPIRepository: Sendable {
     }
 
     private func buildPostUrl(id: Int) -> URL {
-        configuration.siteApiRoot
-            .appending(path: "wp/v2/posts")
-            .appendingPathComponent(String(id))
-            .appending(queryItems: [
-                URLQueryItem(name: "context", value: "edit")
-            ])
+        Self.buildNamespacedURL(
+            apiRoot: configuration.siteApiRoot,
+            path: "/wp/v2/posts/\(id)",
+            namespace: configuration.siteApiNamespace.first
+        ).appending(queryItems: [
+            URLQueryItem(name: "context", value: "edit")
+        ])
     }
 
     // MARK: Editor Settings
@@ -98,11 +151,13 @@ public struct RESTAPIRepository: Sendable {
     }
 
     private func buildPostTypeUrl(type: String) -> URL {
-        configuration.siteApiRoot.appending(path: "wp/v2/types/")
-            .appending(path: type)
-            .appending(queryItems: [
-                URLQueryItem(name: "context", value: "edit")
-            ])
+        Self.buildNamespacedURL(
+            apiRoot: configuration.siteApiRoot,
+            path: "/wp/v2/types/\(type)",
+            namespace: configuration.siteApiNamespace.first
+        ).appending(queryItems: [
+            URLQueryItem(name: "context", value: "edit")
+        ])
     }
 
     // MARK: GET Active Theme

ios/Sources/GutenbergKit/Sources/Services/EditorService.swift

@@ -106,7 +106,7 @@ public actor EditorService {
     /// - Returns: The complete set of dependencies needed to initialize the editor.
     /// - Throws: An error if any required resource fails to download.
     @discardableResult
-    public func prepare(progress: @escaping EditorProgressCallback) async throws -> EditorDependencies {
+    public func prepare(progress: EditorProgressCallback? = nil) async throws -> EditorDependencies {
 
         if self.configuration.isOfflineModeEnabled {
             return EditorDependencies(

ios/Sources/GutenbergKit/Sources/Stores/EditorAssetLibrary.swift

@@ -44,7 +44,7 @@ public actor EditorAssetLibrary {
         let remoteManifest = try RemoteEditorAssetManifest(data: data)
 
         guard
-            let existingManifest = try self.existingBundle(forManifestChecksum: remoteManifest.checksum),
+            let existingManifest = self.existingBundle(forManifestChecksum: remoteManifest.checksum),
             self.cachePolicy.allowsResponseWith(date: existingManifest.downloadDate)
         else {
             return try LocalEditorAssetManifest(remoteManifest: remoteManifest)
@@ -64,7 +64,7 @@ public actor EditorAssetLibrary {
             .filter { $0.hasDirectoryPath }  // Only include directories
             .filter { $0.pathExtension != "download" }  // Don't include bundles that are being downloaded
             .map { $0.appending(path: "manifest.json") }
-            .map { try EditorAssetBundle(url: $0) }
+            .compactMap { try? EditorAssetBundle(url: $0) }  // Skip invalid/incomplete bundles
             .sorted { $0.downloadDate > $1.downloadDate }
     }
 
@@ -81,20 +81,24 @@ public actor EditorAssetLibrary {
         return try await self.buildBundle(for: manifest, progress: progress)
     }
 
-    /// Checks whether a bundle with the given manifest checksum exists on disk.
+    /// Checks whether a complete bundle with the given manifest checksum exists on disk.
     ///
+    /// A bundle is considered complete only if both `manifest.json` and `editor-representation.json` exist.
     package func hasBundle(forManifestChecksum checksum: String) -> Bool {
-        FileManager.default.directoryExists(at: self.bundleRoot(for: checksum))
+        let bundleRoot = self.bundleRoot(for: checksum)
+        let manifestExists = FileManager.default.fileExists(atPath: bundleRoot.appending(path: "manifest.json").path)
+        let editorRepExists = FileManager.default.fileExists(atPath: bundleRoot.appending(path: "editor-representation.json").path)
+        return manifestExists && editorRepExists
     }
-    
+
     /// Retrieves an existing bundle from disk if one exists for the given manifest checksum.
     ///
-    package func existingBundle(forManifestChecksum checksum: String) throws -> EditorAssetBundle? {
+    package func existingBundle(forManifestChecksum checksum: String) -> EditorAssetBundle? {
         guard self.hasBundle(forManifestChecksum: checksum) else {
             return nil
         }
-        
-        return try EditorAssetBundle(url: self.bundleManifestPath(for: checksum))
+
+        return try? EditorAssetBundle(url: self.bundleManifestPath(for: checksum))
     }
 
     // MARK: - Individual Asset Handling
@@ -123,10 +127,8 @@ public actor EditorAssetLibrary {
             bundleRoot: tempDirectory
         )
 
-        try bundle.writeManifest()
-
         let editorRepresentation = try manifest.buildEditorRepresentation(for: self.configuration)
-        try bundle.setEditorRepresentation(editorRepresentation)
+        try bundle.writeManifest(editorRepresentation: editorRepresentation)
 
         try await withThrowingTaskGroup { group in
             let links = (manifest.scripts + manifest.styles).filter { self.isSupportedAsset($0) }
@@ -184,9 +186,18 @@ public actor EditorAssetLibrary {
 
     // MARK: - Helpers
     private func editorAssetsUrl(for configuration: EditorConfiguration) -> URL {
-        configuration.siteApiRoot
-            .appending(path: "/wpcom/v2/editor-assets")
-            .appending(queryItems: [URLQueryItem(name: "exclude", value: "core,gutenberg")])
+        let baseUrl: URL
+        if let customEndpoint = configuration.editorAssetsEndpoint {
+            baseUrl = customEndpoint
+        } else if let namespace = configuration.siteApiNamespace.first {
+            // Insert namespace: /wpcom/v2/editor-assets -> /wpcom/v2/sites/123/editor-assets
+            baseUrl = configuration.siteApiRoot
+                .appending(path: "/wpcom/v2/\(namespace)editor-assets")
+        } else {
+            baseUrl = configuration.siteApiRoot
+                .appending(path: "/wpcom/v2/editor-assets")
+        }
+        return baseUrl.appending(queryItems: [URLQueryItem(name: "exclude", value: "core,gutenberg")])
     }
 
     /// Cleans up outdated library entries for this site.

ios/Tests/GutenbergKitTests/Model/EditorAssetBundleTests.swift

@@ -191,8 +191,8 @@ struct EditorAssetBundleTests {
             manifest: originalBundle.manifest,
             downloadDate: originalBundle.downloadDate
         )
-        let encoded = try JSONEncoder().encode(rawBundle)
-        try encoded.write(to: manifestURL)
+        let bundleToWrite = EditorAssetBundle(raw: rawBundle, bundleRoot: tempDir)
+        try bundleToWrite.writeManifest(editorRepresentation: .empty)
 
         // Initialize from URL
         let loadedBundle = try EditorAssetBundle(url: manifestURL)
@@ -358,8 +358,8 @@ struct EditorAssetBundleTests {
             manifest: originalBundle.manifest,
             downloadDate: originalBundle.downloadDate
         )
-        let encoded = try JSONEncoder().encode(rawBundle)
-        try encoded.write(to: tempURL)
+        let bundleToWrite = EditorAssetBundle(raw: rawBundle, bundleRoot: tempDir)
+        try bundleToWrite.writeManifest(to: tempURL, editorRepresentation: .empty)
 
         // Read back
         let loadedBundle = try EditorAssetBundle(url: tempURL)