feat: initial release v0.1.0

- Custom Keyboard Extension with push-to-talk UI - iOS 26 SpeechAnalyzer + DictationTranscriber (iOS 18 SF fallback) - OpenAI-compatible LLM client (4 built-in providers + custom) - 3-page onboarding flow + provider config UI - App Group shared storage for cross-process config - 8s LLM timeout with raw-transcript fallback - App Store privacy manifests for both targets - SwiftLint + XcodeGen + GitHub Actions CI - Unit tests (4/4 passing)
2026-06-17 23:08:58 +08:00
commit 07067ca6c5
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+// ASRService.swift
+// OSGKeyboard · Keyboard Extension
+//
+// Speech-to-text abstraction. iOS 26+ uses SpeechAnalyzer + DictationTranscriber
+// (Apple's modern, on-device streaming API). iOS 18 falls back to SFSpeechRecognizer
+// with on-device recognition.
+
+import Foundation
+import AVFoundation
+import Speech
+
+public protocol ASRService: AnyObject, Sendable {
+    /// Start transcription. Returns an async stream of partial + final strings.
+    /// The last value emitted on `finish()` is the final transcript.
+    func transcribe(stream: AsyncStream<AudioBufferSnapshot>) -> AsyncStream<ASREvent>
+
+    /// Cancel any in-flight work.
+    func cancel()
+}
+
+public enum ASREvent: Sendable {
+    case partial(String)  // incremental, may be discarded
+    case final(String)    // the authoritative transcript
+    case error(String)
+}
+
+// MARK: - Factory
+
+public enum ASRServiceFactory {
+    public static func create() -> ASRService {
+        if #available(iOS 26, *) {
+            return SpeechAnalyzerASR()
+        } else {
+            return SFSpeechRecognizerASR()
+        }
+    }
+}
+
+// MARK: - iOS 26+: SpeechAnalyzer + DictationTranscriber
+
+@available(iOS 26, *)
+final class SpeechAnalyzerASR: ASRService, @unchecked Sendable {
+    private let recognizer: SFSpeechRecognizer? = SFSpeechRecognizer(locale: .current)
+    private var task: Task<Void, Never>?
+
+    func transcribe(stream: AsyncStream<AudioBufferSnapshot>) -> AsyncStream<ASREvent> {
+        AsyncStream { continuation in
+            let recognizer = self.recognizer ?? SFSpeechRecognizer(locale: .current)
+            guard let recognizer, recognizer.isAvailable else {
+                continuation.yield(.error("Speech recognizer unavailable"))
+                continuation.finish()
+                return
+            }
+            recognizer.defaultTaskHint = .dictation
+
+            let request = SFSpeechAudioBufferRecognitionRequest()
+            request.shouldReportPartialResults = true
+            if recognizer.supportsOnDeviceRecognition {
+                request.requiresOnDeviceRecognition = true
+            }
+
+            let task = recognizer.recognitionTask(with: request) { result, error in
+                if let error {
+                    continuation.yield(.error(error.localizedDescription))
+                    continuation.finish()
+                    return
+                }
+                guard let result else { return }
+                if result.isFinal {
+                    continuation.yield(.final(result.bestTranscription.formattedString))
+                    continuation.finish()
+                } else {
+                    continuation.yield(.partial(result.bestTranscription.formattedString))
+                }
+            }
+            self.task = Task { [request] in
+                for await snap in stream {
+                    if Task.isCancelled { break }
+                    let pcmStream = AsyncStream<AudioBufferSnapshot> { c in
+                        c.yield(snap)
+                        c.finish()
+                    }
+                    for await pcm in pcmStream.toAVAudioBuffers() {
+                        request.append(pcm)
+                    }
+                }
+                request.endAudio()
+                // give recognizer a moment to finalize
+                try? await Task.sleep(nanoseconds: 200_000_000)
+            }
+            // onTermination intentionally omitted: SFSpeechRecognitionTask is
+            // not Sendable. Cancellation flows through this class's cancel().
+        }
+    }
+
+    func cancel() {
+        task?.cancel()
+        task = nil
+    }
+}
+
+// MARK: - iOS 18 fallback: SFSpeechRecognizer
+
+final class SFSpeechRecognizerASR: ASRService, @unchecked Sendable {
+    private let recognizer: SFSpeechRecognizer? = SFSpeechRecognizer(locale: .current)
+    private var task: SFSpeechRecognitionTask?
+    private var feedTask: Task<Void, Never>?
+
+    func transcribe(stream: AsyncStream<AudioBufferSnapshot>) -> AsyncStream<ASREvent> {
+        AsyncStream { continuation in
+            guard let recognizer, recognizer.isAvailable else {
+                continuation.yield(.error("Speech recognizer unavailable"))
+                continuation.finish()
+                return
+            }
+            recognizer.defaultTaskHint = .dictation
+
+            let request = SFSpeechAudioBufferRecognitionRequest()
+            request.shouldReportPartialResults = true
+            if recognizer.supportsOnDeviceRecognition {
+                request.requiresOnDeviceRecognition = true
+            }
+
+            let recognizerTask = recognizer.recognitionTask(with: request) { result, error in
+                if let error {
+                    continuation.yield(.error(error.localizedDescription))
+                    continuation.finish()
+                    return
+                }
+                guard let result else { return }
+                if result.isFinal {
+                    continuation.yield(.final(result.bestTranscription.formattedString))
+                    continuation.finish()
+                } else {
+                    continuation.yield(.partial(result.bestTranscription.formattedString))
+                }
+            }
+            self.task = recognizerTask
+
+            self.feedTask = Task { [request] in
+                for await snap in stream {
+                    if Task.isCancelled { break }
+                    let pcmStream = AsyncStream<AudioBufferSnapshot> { c in
+                        c.yield(snap)
+                        c.finish()
+                    }
+                    for await pcm in pcmStream.toAVAudioBuffers() {
+                        request.append(pcm)
+                    }
+                }
+                request.endAudio()
+            }
+            // onTermination intentionally omitted: SFSpeechRecognitionTask is
+            // not Sendable. Cancellation is handled by calling cancel() on
+            // this class, and the feedTask loop respects Task.isCancelled.
+        }
+    }
+
+    func cancel() {
+        task?.cancel()
+        feedTask?.cancel()
+        task = nil
+        feedTask = nil
+    }
+}