Patch for react-native-sherpa-onnx-offline-tts to add generate() method

sherpa-onnx-generate-method.patch

diff --git a/ios/SherpaOnnxOfflineTts.mm b/ios/SherpaOnnxOfflineTts.mm
index 1234567..abcdefg 100644
--- a/ios/SherpaOnnxOfflineTts.mm
+++ b/ios/SherpaOnnxOfflineTts.mm
@@ -5,6 +5,13 @@
 // Initialize method exposed to React Native
 RCT_EXTERN_METHOD(initializeTTS:(double)sampleRate channels:(NSInteger)channels modelId:(NSString *)modelId)
 
+// Generate method exposed to React Native (saves to WAV file)
+RCT_EXTERN_METHOD(generate:(NSString *)text
+                  sid:(NSInteger)sid
+                  speed:(double)speed
+                  resolver:(RCTPromiseResolveBlock)resolver
+                  rejecter:(RCTPromiseRejectBlock)rejecter)
+
 // Generate and Play method exposed to React Native
 RCT_EXTERN_METHOD(generateAndPlay:(NSString *)text
                   sid:(NSInteger)sid
diff --git a/ios/SherpaOnnxOfflineTts.swift b/ios/SherpaOnnxOfflineTts.swift
index 1234567..abcdefg 100644
--- a/ios/SherpaOnnxOfflineTts.swift
+++ b/ios/SherpaOnnxOfflineTts.swift
@@ -113,6 +113,76 @@ class TTSManager: RCTEventEmitter, AudioPlayerDelegate {
         realTimeAudioPlayer?.playAudioData(from: audio)
     }
     
+    // Generate audio and save to WAV file
+    @objc(generate:sid:speed:resolver:rejecter:)
+    func generate(_ text: String, sid: Int, speed: Double, resolver: @escaping RCTPromiseResolveBlock, rejecter: @escaping RCTPromiseRejectBlock) {
+        let trimmedText = text.trimmingCharacters(in: .whitespacesAndNewlines)
+
+        guard !trimmedText.isEmpty else {
+            rejecter("EMPTY_TEXT", "Input text is empty", nil)
+            return
+        }
+
+        guard let tts = self.tts else {
+            rejecter("NOT_INITIALIZED", "TTS was never initialized", nil)
+            return
+        }
+
+        print("Generating audio for text length: \(trimmedText.count)")
+        let startTime = Date()
+
+        let audio = tts.generate(text: trimmedText, sid: sid, speed: Float(speed))
+
+        let endTime = Date()
+        let generationTime = endTime.timeIntervalSince(startTime)
+        print("Time taken for TTS generation: \(generationTime) seconds")
+
+        // Save to WAV file
+        do {
+            let wavPath = try saveToWavFile(audio: audio)
+            print("WAV file saved to: \(wavPath)")
+            resolver(wavPath)
+        } catch {
+            rejecter("WAV_SAVE_ERROR", "Failed to save WAV file: \(error.localizedDescription)", error)
+        }
+    }
+
+    // Helper function to save audio to WAV file
+    private func saveToWavFile(audio: SherpaOnnxGeneratedAudioWrapper) throws -> String {
+        let samples = audio.samples
+        let sampleRate = audio.sampleRate
+
+        // Create temporary file path
+        let tempDir = NSTemporaryDirectory()
+        let uuid = UUID().uuidString
+        let wavPath = "\(tempDir)sherpa-\(uuid).wav"
+
+        // Convert Float samples to Int16 PCM
+        var pcmSamples: [Int16] = []
+        for sample in samples {
+            let clampedSample = max(-1.0, min(1.0, sample))
+            let int16Sample = Int16(clampedSample * 32767.0)
+            pcmSamples.append(int16Sample)
+        }
+
+        // Write WAV file
+        let audioFormat = AVAudioFormat(commonFormat: .pcmFormatInt16,
+                                       sampleRate: Double(sampleRate),
+                                       channels: 1,
+                                       interleaved: false)!
+
+        let audioFile = try AVAudioFile(forWriting: URL(fileURLWithPath: wavPath),
+                                        settings: audioFormat.settings)
+
+        let buffer = AVAudioPCMBuffer(pcmFormat: audioFormat, frameCapacity: UInt32(pcmSamples.count))!
+        buffer.frameLength = UInt32(pcmSamples.count)
+
+        let channelData = buffer.int16ChannelData![0]
+        for i in 0..<pcmSamples.count {
+            channelData[i] = pcmSamples[i]
+        }
+
+        try audioFile.write(from: buffer)
+
+        return wavPath
+    }
+
     // Clean up resources
     @objc func deinitialize() {
         self.realTimeAudioPlayer?.stop()
diff --git a/src/index.tsx b/src/index.tsx
index 1234567..abcdefg 100644
--- a/src/index.tsx
+++ b/src/index.tsx
@@ -9,6 +9,15 @@ const initialize = (modelId: string) => {
   TTSManager.initializeTTS(22050, 1, modelId);
 };
 
+const generate = async (text: any, sid: any, speed: any) => {
+  try {
+    const wavPath = await TTSManager.generate(text, sid, speed);
+    return wavPath;
+  } catch (error) {
+    console.error(error);
+    throw error;
+  }
+};
+
 const generateAndPlay = async (text: any, sid: any, speed: any) => {
   try {
     const result = await TTSManager.generateAndPlay(text, sid, speed);
@@ -18,6 +27,10 @@ const generateAndPlay = async (text: any, sid: any, speed: any) => {
   }
 };
 
+const stopPlaying = () => {
+  TTSManager.stopPlaying();
+};
+
 const deinitialize = () => {
   TTSManager.deinitialize();
 };
@@ -34,7 +47,9 @@ const addVolumeListener = (callback: any) => {
 
 export default {
   initialize,
+  generate,
   generateAndPlay,
+  stopPlaying,
   deinitialize,
   addVolumeListener,
 };