WorkIndicator/Audio/AudioDevice.cs

using NAudio.CoreAudioApi;
using NAudio.CoreAudioApi.Interfaces;
using Serilog;
using System.Collections.Generic;
using System.Linq;

namespace WorkIndicator.Audio;

internal class AudioDevice
{
    private readonly ILogger _logger;

    public delegate void AudioSessionsChangedDelegate();

    public event AudioSessionsChangedDelegate AudioSessionsChanged;

    public bool IsMuted { get; private set; }

    public string FriendlyName { get; }

    public Dictionary<string, AudioSession> Sessions { get; } = new();

    public AudioDevice(MMDevice device)
    {
        _logger = Log.ForContext<AudioDevice>();

        FriendlyName = device.DeviceFriendlyName;
        IsMuted = device.AudioEndpointVolume.Mute;

        _logger.Information("AudioDevice: {name} {muted}", FriendlyName, IsMuted);

        device.AudioEndpointVolume.OnVolumeNotification += AudioEndpointVolume_OnVolumeNotification;
        device.AudioSessionManager.OnSessionCreated += AudioSessionManager_OnSessionCreated;

        device.AudioSessionManager.RefreshSessions();
        var sessions = device.AudioSessionManager.Sessions;

        for (var i = 0; i < sessions.Count; i++)
        {
            SetupSession(sessions[i]);
        }
    }

    private void AudioEndpointVolume_OnVolumeNotification(AudioVolumeNotificationData data)
    {
        _logger.Information("AudioEndpointVolume_OnVolumeNotification: {name} {muted}", FriendlyName, data.Muted);

        IsMuted = data.Muted;

        AudioSessionsChanged?.Invoke();
    }

    private void AudioSessionManager_OnSessionCreated(object sender, IAudioSessionControl newSession)
    {
        var session = new AudioSessionControl(newSession);

        _logger.Information("OnSessionCreated: {name}", session.GetSessionIdentifier);

        SetupSession(session);
    }

    private void SetupSession(AudioSessionControl session)
    {
        _logger.Information("SetupSession: {name}", session.GetSessionIdentifier);

        var audioSession = new AudioSession(session, FriendlyName);
        
        Sessions[session.GetSessionIdentifier] = audioSession;

        audioSession.AudioSessionChanged += AudioSession_AudioSessionChanged;

        AudioSessionsChanged?.Invoke();
    }

    private void AudioSession_AudioSessionChanged(string id, AudioSessionState state)
    {
        _logger.Information("AudioSessionChanged: {id} {state}", id, state);

        AudioSessionsChanged?.Invoke();

        if (state == AudioSessionState.AudioSessionStateExpired)
        {
            Sessions.Remove(id);
        }
    }

    public int ActiveSessionCount => Sessions.Values.Count(s => s.State == AudioSessionState.AudioSessionStateActive);
}