FocusVolumeControlPlugin/src/SoundBrowser/MainWindow.xaml.cs

using CoreAudio;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace SoundBrowser
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            dele = new WinEventDelegate(WinEventProc);
            IntPtr m_hhook = SetWinEventHook(EVENT_SYSTEM_FOREGROUND, EVENT_SYSTEM_FOREGROUND, IntPtr.Zero, dele, 0, 0, WINEVENT_OUTOFCONTEXT);
        }


        WinEventDelegate dele = null;


        delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);

        [DllImport("user32.dll")]
        static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);

        private const uint WINEVENT_OUTOFCONTEXT = 0;
        private const uint EVENT_SYSTEM_FOREGROUND = 3;

        [DllImport("user32.dll")]
        static extern IntPtr GetForegroundWindow();

        [DllImport("user32.dll", SetLastError = true)]
        static extern uint GetWindowThreadProcessId(IntPtr hWnd, out int processId);

        [DllImport("user32.dll")]
        static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count);

        private static SimpleAudioVolume GetVolumeObject(Process process)
        {
            var deviceEnumerator = new MMDeviceEnumerator(Guid.NewGuid());

            using var device = deviceEnumerator.GetDefaultAudioEndpoint(DataFlow.Render, Role.Multimedia);
            using var manager = device.AudioSessionManager2;

            var sessions = manager.Sessions;

            foreach (var session in sessions)
            {
                if (session.ProcessID == process.Id)
                {
                    return session.SimpleAudioVolume;
                }

                var audioProcess = Process.GetProcessById((int)session.ProcessID);
                if(audioProcess?.ProcessName == process.ProcessName)
                {
                    Console.WriteLine(process.MainModule.FileVersionInfo.FileDescription);
                    return session.SimpleAudioVolume;
                }
            }
            return null;
        }


        SimpleAudioVolume _current;

        private string GetActiveWindowTitle()
        {
            const int nChars = 256;
            IntPtr handle = IntPtr.Zero;
            StringBuilder Buff = new StringBuilder(nChars);
            handle = GetForegroundWindow();

            if (handle <= 0)
            {
                return "";
            }

            var tid = GetWindowThreadProcessId(handle, out var pid);
            var process = Process.GetProcessById(pid);

            var vol = GetVolumeObject(process);
            _current = vol;
            if(vol != null)
            {
                vol.Mute = true;
            }

            return $"{pid} vol:{vol?.MasterVolume ?? -1} - {process.ProcessName}";
        }


        public void WinEventProc(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
        {
            _tf.Text = GetActiveWindowTitle();
        }
    }

}