import AVFoundation
import CoreAudio
import Foundation
enum AudioEngineError: Error, LocalizedError {
case invalidFormat
case engineNotRunning
case noInputNode
case deviceSetupFailed(String)
var errorDescription: String? {
switch self {
case .invalidFormat:
return "Invalid audio format"
case .engineNotRunning:
return "Audio engine is not running"
case .noInputNode:
return "No input node available"
case .deviceSetupFailed(let reason):
return "Device setup failed: \(reason)"
}
}
}
@MainActor
@Observable
final class AudioEngineController {
private(set) var isRunning = false
@ObservationIgnored
private var engine: AVAudioEngine?
@ObservationIgnored
private var routeObserver: NSObjectProtocol?
@ObservationIgnored
private var isHandlingRouteChange = false
var onRouteChange: (() async -> Void)?
var inputNode: AVAudioInputNode? {
engine?.inputNode
}
var inputFormat: AVAudioFormat? {
engine?.inputNode.outputFormat(forBus: 0)
}
// MARK: - Setup
func setup() async throws -> AVAudioInputNode {
cleanup()
let newEngine = AVAudioEngine()
engine = newEngine
let input = newEngine.inputNode
let format = input.inputFormat(forBus: 0)
guard format.sampleRate > 0, format.channelCount > 0 else {
throw AudioEngineError.invalidFormat
}
showDeviceName()
try await Task.detached(priority: .userInitiated) {
try newEngine.start()
}.value
isRunning = true
setupRouteObserver()
return input
}
// TODO: Improve this function
func showDeviceName() {
var deviceId = AudioDeviceID(0)
var deviceSize = UInt32(MemoryLayout.size(ofValue: deviceId))
var address = AudioObjectPropertyAddress(
mSelector: kAudioHardwarePropertyDefaultInputDevice,
mScope: kAudioObjectPropertyScopeGlobal,
mElement: kAudioObjectPropertyElementMain
)
var err = AudioObjectGetPropertyData(
AudioObjectID(kAudioObjectSystemObject),
&address,
0,
nil,
&deviceSize,
&deviceId
)
if err == 0 {
// change the query property and use previously fetched details
address.mSelector = kAudioDevicePropertyDeviceNameCFString
var deviceName = "" as CFString
deviceSize = UInt32(MemoryLayout.size(ofValue: deviceName))
err = AudioObjectGetPropertyData(
deviceId,
&address,
0,
nil,
&deviceSize,
&deviceName
)
if err == 0 {
AppLogger.shared
.audioManager.debug(
"### current default mic:: \(deviceName) "
)
} else {
// TODO:: unable to fetch device name
}
} else {
// TODO:: unable to fetch the default input device
}
}
// MARK: - Cleanup
func cleanup() {
AppLogger.shared.audioManager.debug("🧹 Cleaning up audio engine")
if let node = engine?.inputNode {
node.removeTap(onBus: 0)
AppLogger.shared.audioManager.debug("✅ Tap removed")
}
if let engine, engine.isRunning {
engine.stop()
AppLogger.shared.audioManager.debug("✅ Engine stopped")
}
removeRouteObserver()
engine = nil
isRunning = false
}
// MARK: - Tap Installation
func installTap(
bufferSize: AVAudioFrameCount = 1024,
handler: @escaping (AVAudioPCMBuffer, AVAudioFormat) -> Void
) throws {
guard let node = inputNode else {
throw AudioEngineError.noInputNode
}
guard isRunning else {
throw AudioEngineError.engineNotRunning
}
node.installTap(onBus: 0, bufferSize: bufferSize, format: nil) {
buffer,
_ in
handler(buffer, buffer.format)
}
AppLogger.shared.audioManager.debug("✅ Microphone tap installed")
}
// MARK: - Device Management
private func getSystemDefaultInputDeviceID() -> AudioDeviceID? {
var deviceID: AudioDeviceID = 0
var size = UInt32(MemoryLayout<AudioDeviceID>.size)
var address = AudioObjectPropertyAddress(
mSelector: kAudioHardwarePropertyDefaultInputDevice,
mScope: kAudioObjectPropertyScopeGlobal,
mElement: kAudioObjectPropertyElementMain
)
let status = AudioObjectGetPropertyData(
AudioObjectID(kAudioObjectSystemObject),
&address,
0,
nil,
&size,
&deviceID
)
return status == noErr && deviceID != 0 ? deviceID : nil
}
}
// MARK: - Private Helpers
extension AudioEngineController {
fileprivate func setupRouteObserver() {
removeRouteObserver()
routeObserver = NotificationCenter.default.addObserver(
forName: .AVAudioEngineConfigurationChange,
object: engine,
queue: .main
) { [weak self] _ in
guard let self else { return }
AppLogger.shared.audioManager.debug(
"🔄 Audio engine configuration changed"
)
Task { @MainActor in
guard !self.isHandlingRouteChange else { return }
self.isHandlingRouteChange = true
defer { self.isHandlingRouteChange = false }
await self.onRouteChange?()
}
}
}
fileprivate func removeRouteObserver() {
if let observer = routeObserver {
NotificationCenter.default.removeObserver(observer)
routeObserver = nil
}
}
}
