//
//  AudioRecordService.swift
//  AutoCatCore
//
//  Created by Selim Mustafaev on 11.03.2025.
//  Copyright © 2025 Selim Mustafaev. All rights reserved.
//

import AVFoundation
import Speech

public final class AudioRecordService {
    
    let audioFileSettings: [String : Any] = [
        AVFormatIDKey: kAudioFormatMPEG4AAC,
        AVSampleRateKey: 44100,
        AVNumberOfChannelsKey: 2,
    ]
    
    var recorder: AVAudioRecorder?
    
    public init() {
        
    }
    
    @discardableResult
    func requestRecognitionAuthorization() async -> SFSpeechRecognizerAuthorizationStatus {
        
        let status = SFSpeechRecognizer.authorizationStatus()
        guard status == .notDetermined else {
            return status
        }
        
        return await withCheckedContinuation { continuation in
            SFSpeechRecognizer.requestAuthorization { status in
                continuation.resume(returning: status)
            }
        }
    }
}

extension AudioRecordService: AudioRecordServiceProtocol {
    
    public func requestPermissions() async -> Bool {
        
        await requestRecognitionAuthorization()
        return await AVAudioApplication.requestRecordPermission()
    }
    
    public func startRecording(to url: URL) async throws {
        guard AVAudioApplication.shared.recordPermission != .denied else {
            throw AudioRecordError.permissionDenied
        }
        
        switch AVAudioApplication.shared.recordPermission {
        case .denied:
            throw AudioRecordError.permissionDenied
        case .undetermined:
            if await AVAudioApplication.requestRecordPermission() {
                break
            } else {
                return
            }
        case .granted:
            break
        @unknown default:
            throw AudioRecordError.unknown
        }
        
        try AVAudioSession.sharedInstance().setCategory(.playAndRecord)
        try AVAudioSession.sharedInstance().setActive(true)
        
        recorder = try AVAudioRecorder(url: url, settings: audioFileSettings)
        recorder?.record()
    }
    
    public func stopRecording() {
        
        recorder?.stop()
        recorder = nil
    }
    
    public func recognizeText(from url: URL) async -> String? {
        
        guard let recognizer = SFSpeechRecognizer(locale: Locale(identifier: "ru-RU")), recognizer.isAvailable else {
            return nil
        }
        
        let request = SFSpeechURLRecognitionRequest(url: url)
        
        return await withCheckedContinuation { continuation in
            recognizer.recognitionTask(with: request) { result, error in
                continuation.resume(returning: result?.bestTranscription.formattedString)
            }
        }
    }
}