Integrate Translation framework

Modules/Sources/WordPressIntelligence/UseCases/TranslationViewModel.swift

@@ -0,0 +1,133 @@
+import Foundation
+import SwiftUI
+import WebKit
+import Translation
+import NaturalLanguage
+import Combine
+import WordPressShared
+
+@available(iOS 26, *)
+@MainActor
+public final class TranslationViewModel: ObservableObject {
+    @Published var configuration: TranslationSession.Configuration?
+
+    private var content: [String] = []
+    private var continuation: CheckedContinuation<[String], Error>?
+
+    public init() {}
+
+    public func translate(_ content: String, to targetLanguage: Locale.Language) async throws -> String {
+        let content = try await translate([content], to: targetLanguage)
+        guard let first = content.first else {
+            throw URLError(.unknown) // Should never happen
+        }
+        return first
+    }
+
+    /// Translate content to the specified target language.
+    ///
+    /// This method detects the source language automatically and translates each string
+    /// in the content array independently.
+    public func translate(
+        _ content: [String],
+        from source: Locale.Language? = nil,
+        to target: Locale.Language = Locale.current.language
+    ) async throws -> [String] {
+        wpAssert(continuation == nil, "Translation in progress")
+
+        self.content = content
+        return try await withCheckedThrowingContinuation { continuation in
+            self.continuation = continuation
+
+            // This will trigger the .translationTask in TranslationHostView
+            if self.configuration != nil {
+                // Yes, this is how you restart translation with the existing configuration
+                // in the Translation framework.
+                self.configuration?.invalidate()
+            } else {
+                self.configuration = TranslationSession.Configuration(source: source, target: target)
+            }
+        }
+    }
+
+    /// Check if translation is available for the given content.
+    public func checkAvailability(for content: String, to targetLanguage: Locale.Language = Locale.current.language) async -> TranslationAvailability {
+        // Important. The `Translation` framework is effective at translating
+        // HTML, but the `status(...)` method and `NLLanguageRecognizer`
+        // incorrectly identify dominant langauge as English if a post has a
+        // signifcant amount of HTML tags and/or CSS styles.
+        let content = (try? ContentExtractor.extractRelevantText(from: content)) ?? content
+
+        guard let identifier = IntelligenceService.detectLanguage(from: content) else {
+            return .unavailable
+        }
+        let sourceLanguage = Locale.Language(identifier: identifier)
+
+        let availability = LanguageAvailability()
+        let status = await availability.status(from: sourceLanguage, to: targetLanguage)
+        guard status == .installed || status == .supported else {
+            return .unavailable
+        }
+        return .available(sourceLanguage: sourceLanguage, targetLanguage: targetLanguage)
+    }
+
+    fileprivate func performTranslation(session: TranslationSession) async {
+        do {
+            var output: [String] = []
+            for string in content {
+                try Task.checkCancellation()
+                let result = try await session.translate(string)
+                output.append(result.targetText)
+            }
+            finish(with: .success(output))
+        } catch {
+            if (error as NSError).domain == NSCocoaErrorDomain && (error as NSError).code == NSUserCancelledError {
+                finish(with: .failure(CancellationError()))
+            } else {
+                finish(with: .failure(error))
+            }
+        }
+    }
+
+    private func finish(with result: Result<[String], Error>) {
+        content = []
+        if let continuation {
+            self.continuation = nil
+            continuation.resume(with: result)
+        }
+    }
+}
+
+public enum TranslationAvailability {
+    case unavailable
+    case available(sourceLanguage: Locale.Language, targetLanguage: Locale.Language)
+}
+
+// MARK: - TranslationHostView (SwiftUI)
+
+/// SwiftUI view that hosts translation functionality using .translationTask()
+///
+/// This view manages the translation session lifecycle. It observes the view model's
+/// configuration and triggers translation when it changes.
+///
+/// **IMPORTANT**: The `session` object must NEVER leave the `.translationTask` closure.
+/// Capturing or storing the session causes crashes.
+@available(iOS 26, *)
+public struct TranslationHostView: View {
+    @ObservedObject var viewModel: TranslationViewModel
+
+    public init(viewModel: TranslationViewModel) {
+        self.viewModel = viewModel
+    }
+
+    public var body: some View {
+        Color.clear
+            .frame(width: 0, height: 0)
+            .translationTask(viewModel.configuration) { session in
+                await viewModel.performTranslation(session: session)
+            }
+    }
+}
+
+@available(iOS 18.0, *)
+extension TranslationSession: @retroactive @unchecked(Sendable) {}

RELEASE-NOTES.txt

@@ -1,15 +1,15 @@
 26.6
 -----
+* [**] Intelligence: Expand AI-based features to more locales [#25034]
 * [**] Reader: Add "Freshly Pressed" to Discover [#24828]
 * [*] Reader: Keep only one "Search" option in the main sidebar [#25116]
 * [*] Reader: Fix Send button design in Comments [#25092]
-* [**] Intelligence: Expand AI-based features to more locales [#25034]
+* [*] Reader: Add translation support for posts [#25089]
 * [*] Fix previewing posts on WordPress.com atomic sites [#25045]
 * [*] Stats: Rename "External Links" to "Clicks" to be consistent with the web [#25090]
 * [*] Stats: Fix locations data discrepancy with the web [#25105]
 
 
-
 26.5
 -----
 * [*] Add "Status" field to the "Post Settings" screen to make it easier to move posts from one state to another [#24939]

WordPress/Classes/ViewRelated/Reader/Controllers/ReaderPostActions/ReaderPostMenu.swift

@@ -27,7 +27,8 @@ struct ReaderPostMenu {
             copyPostLink,
             viewPostInBrowser,
             post.isSeenSupported ? toggleSeen : nil,
-            summarize
+            summarize,
+            translate
         ].compactMap { $0 })
     }
 
@@ -132,6 +133,19 @@ struct ReaderPostMenu {
         }
     }
 
+    private var translate: UIAction? {
+        guard #available(iOS 26, *),
+              let detailVC = viewController as? ReaderDetailViewController,
+              case .available = detailVC.translationAvailability else {
+            return nil
+        }
+
+        return UIAction(Strings.translate, systemImage: "translate") {
+            detailVC.translatePost()
+            track(.translate)
+        }
+    }
+
     private func manageNotifications(for siteID: Int) -> UIAction {
         UIAction(Strings.manageNotifications, systemImage: "bell") {
             guard let viewController else { return }
@@ -233,6 +247,7 @@ private enum ReaderPostMenuAnalyticsButton: String {
     case markRead = "mark_read"
     case markUnread = "mark_unread"
     case summarize = "summarize"
+    case translate = "translate"
 }
 
 private enum Strings {
@@ -248,4 +263,5 @@ private enum Strings {
     static let markRead = NSLocalizedString("reader.postContextMenu.markRead", value: "Mark as Read", comment: "Context menu action")
     static let markUnread = NSLocalizedString("reader.postContextMenu.markUnread", value: "Mark as Unread", comment: "Context menu action")
     static let summarize = NSLocalizedString("reader.postContextMenu.summarize", value: "Summarize", comment: "Context menu action")
+    static let translate = NSLocalizedString("reader.postContextMenu.translate", value: "Translate", comment: "Context menu action to translate post content")
 }