react-native-vision-camera/package/ios/CameraView+AVAudioSession.swift

//
//  CameraView+AVAudioSession.swift
//  VisionCamera
//
//  Created by Marc Rousavy on 26.03.21.
//  Copyright © 2021 mrousavy. All rights reserved.
//

import AVFoundation
import Foundation

/**
 Extension for CameraView that sets up the AVAudioSession.
 */
extension CameraView {
  /**
   Configures the Audio Capture Session with an audio input and audio data output.
   */
  final func configureAudioSession() {
    ReactLogger.log(level: .info, message: "Configuring Audio Session...")

    audioCaptureSession.beginConfiguration()
    defer {
      audioCaptureSession.commitConfiguration()
    }

    audioCaptureSession.automaticallyConfiguresApplicationAudioSession = false
    let enableAudio = audio?.boolValue == true

    // check microphone permission
    if enableAudio {
      let audioPermissionStatus = AVCaptureDevice.authorizationStatus(for: .audio)
      if audioPermissionStatus != .authorized {
        invokeOnError(.permission(.microphone))
        return
      }
    }

    // Audio Input
    do {
      if let audioDeviceInput = audioDeviceInput {
        audioCaptureSession.removeInput(audioDeviceInput)
        self.audioDeviceInput = nil
      }
      if enableAudio {
        ReactLogger.log(level: .info, message: "Adding Audio input...")
        guard let audioDevice = AVCaptureDevice.default(for: .audio) else {
          invokeOnError(.device(.microphoneUnavailable))
          return
        }
        audioDeviceInput = try AVCaptureDeviceInput(device: audioDevice)
        guard audioCaptureSession.canAddInput(audioDeviceInput!) else {
          invokeOnError(.parameter(.unsupportedInput(inputDescriptor: "audio-input")))
          return
        }
        audioCaptureSession.addInput(audioDeviceInput!)
      }
    } catch let error as NSError {
      invokeOnError(.device(.microphoneUnavailable), cause: error)
      return
    }

    // Audio Output
    if let audioOutput = audioOutput {
      audioCaptureSession.removeOutput(audioOutput)
      self.audioOutput = nil
    }
    if enableAudio {
      ReactLogger.log(level: .info, message: "Adding Audio Data output...")
      audioOutput = AVCaptureAudioDataOutput()
      guard audioCaptureSession.canAddOutput(audioOutput!) else {
        invokeOnError(.parameter(.unsupportedOutput(outputDescriptor: "audio-output")))
        return
      }
      audioOutput!.setSampleBufferDelegate(self, queue: CameraQueues.audioQueue)
      audioCaptureSession.addOutput(audioOutput!)
    }
  }

  /**
   Configures the Audio session and activates it. If the session was active it will shortly be deactivated before configuration.

   The Audio Session will be configured to allow background music, haptics (vibrations) and system sound playback while recording.
   Background audio is allowed to play on speakers or bluetooth speakers.
   */
  final func activateAudioSession() {
    ReactLogger.log(level: .info, message: "Activating Audio Session...")

    do {
      try AVAudioSession.sharedInstance().updateCategory(AVAudioSession.Category.playAndRecord,
                                                         options: [.mixWithOthers,
                                                                   .allowBluetoothA2DP,
                                                                   .defaultToSpeaker,
                                                                   .allowAirPlay])

      if #available(iOS 14.5, *) {
        // prevents the audio session from being interrupted by a phone call
        try AVAudioSession.sharedInstance().setPrefersNoInterruptionsFromSystemAlerts(true)
      }

      audioCaptureSession.startRunning()
    } catch let error as NSError {
      switch error.code {
      case 561_017_449:
        self.invokeOnError(.session(.audioInUseByOtherApp), cause: error)
      default:
        self.invokeOnError(.session(.audioSessionFailedToActivate), cause: error)
      }
    }
  }

  final func deactivateAudioSession() {
    ReactLogger.log(level: .info, message: "Deactivating Audio Session...")

    audioCaptureSession.stopRunning()
  }

  @objc
  func audioSessionInterrupted(notification: Notification) {
    ReactLogger.log(level: .error, message: "Audio Session Interruption Notification!")
    guard let userInfo = notification.userInfo,
          let typeValue = userInfo[AVAudioSessionInterruptionTypeKey] as? UInt,
          let type = AVAudioSession.InterruptionType(rawValue: typeValue) else {
      return
    }

    // TODO: Add JS-Event for Audio Session interruptions?
    switch type {
    case .began:
      // Something interrupted our Audio Session, stop recording audio.
      ReactLogger.log(level: .error, message: "The Audio Session was interrupted!")
    case .ended:
      ReactLogger.log(level: .info, message: "The Audio Session interruption has ended.")
      guard let optionsValue = userInfo[AVAudioSessionInterruptionOptionKey] as? UInt else { return }
      let options = AVAudioSession.InterruptionOptions(rawValue: optionsValue)
      if options.contains(.shouldResume) {
        if isRecording {
          CameraQueues.audioQueue.async {
            ReactLogger.log(level: .info, message: "Resuming interrupted Audio Session...")
            // restart audio session because interruption is over
            self.activateAudioSession()
          }
        }
      } else {
        ReactLogger.log(level: .error, message: "Cannot resume interrupted Audio Session!")
      }
    @unknown default:
      ()
    }
  }
}