import SwiftUI
import Speech
import AVFoundation
@_cdecl("startRecordingFunc")
public func startRecordingFunc() {
    let voiceRecognitionManager = VoiceRecognitionManager.shared
    voiceRecognitionManager.startRecording()
}
@_cdecl("stopRecordingFunc")
public func stopRecordingFunc() {
    let voiceRecognitionManager = VoiceRecognitionManager.shared
    voiceRecognitionManager.stopRecording()
}
// UnityのC#側で定義されたコールバックをSwiftから呼び出す
@_cdecl("OnRecognizedText")
public func OnRecognizedText(_ recognizedText: UnsafePointer<CChar>) {
    // Unityに認識結果を送る
    let unityCallback = VoiceRecognitionManager.unityCallback
    unityCallback?(String(cString: recognizedText))
}
class VoiceRecognitionManager {
    static let shared = VoiceRecognitionManager()
    
    private var audioEngine = AVAudioEngine()
    private var speechRecognizer = SFSpeechRecognizer(locale: Locale(identifier: "it-IT"))
    private var request = SFSpeechAudioBufferRecognitionRequest()
    private var task: SFSpeechRecognitionTask?
    
    public var recognizedText: String = "話してください..."
    
    // Unityのコールバックを保持するためのプロパティ
    static var unityCallback: ((String) -> Void)?
    
    public func startRecording() {
        SFSpeechRecognizer.requestAuthorization { authStatus in
            if authStatus == .authorized {
                DispatchQueue.main.async {
                    self.startAudioEngine()
                }
            } else {
                DispatchQueue.main.async {
                    if #available(iOS 13.0, *) {
                        self.recognizedText = "音声認識が許可されていません。"
                    }
                }
            }
        }
    }
    
    private func startAudioEngine() {
        let inputNode = audioEngine.inputNode
        let recordingFormat = inputNode.outputFormat(forBus: 0)
        inputNode.installTap(onBus: 0, bufferSize: 1024, format: recordingFormat) { buffer, _ in
            self.request.append(buffer)
        }
        
        audioEngine.prepare()
        
        do {
            try audioEngine.start()
            if #available(iOS 13.0, *) {
                recognizedText = "聞き取っています..."
            }
        } catch {
            if #available(iOS 13.0, *) {
                recognizedText = "オーディオエンジンの起動に失敗しました。"
            }
        }
        
        request.shouldReportPartialResults = true
        if #available(iOS 13.0, *) {
            request.requiresOnDeviceRecognition = true
        }
        
        task = speechRecognizer?.recognitionTask(with: request, resultHandler: { result, error in
            if let result = result {
                DispatchQueue.main.async {
                    // 認識されたテキストを `recognizedText` に代入
                    self.recognizedText = result.bestTranscription.formattedString
                    
                    // UnityのC#側のコールバックを呼び出す
                    if let unityCallback = VoiceRecognitionManager.unityCallback {
                        unityCallback(self.recognizedText)
                    }
                }
            }
            
            if error != nil {
                self.audioEngine.stop()
                inputNode.removeTap(onBus: 0)
            }
        })
    }
    
    func stopRecording() {
        audioEngine.stop()
        request.endAudio()
        task?.cancel()
    }
}