Fix deadlock and auto leave voice channel after 3 min

* Fix for thread being busy handling discord commands blocking audioplayer to timeout
* Auto leave if alone in voice channel after 3 min

Bot/Service/VoiceChannelMonitorService.cs

@@ -0,0 +1,59 @@
+using Discord.WebSocket;
+
+namespace Lunaris2.Service;
+
+public class VoiceChannelMonitorService
+{
+    private readonly DiscordSocketClient _client;
+    private readonly Dictionary<ulong, Timer> _timers = new();
+
+    public VoiceChannelMonitorService(DiscordSocketClient client)
+    {
+        _client = client;
+    }
+
+    public void StartMonitoring()
+    {
+        Task.Run(async () =>
+        {
+            while (true)
+            {
+                await CheckVoiceChannels();
+                await Task.Delay(TimeSpan.FromMinutes(1));
+            }
+        });
+    }
+
+    private async Task CheckVoiceChannels()
+    {
+        foreach (var guild in _client.Guilds)
+        {
+            var voiceChannel = guild.VoiceChannels.FirstOrDefault(vc => vc.ConnectedUsers.Count == 1);
+            if (voiceChannel != null)
+            {
+                if (!_timers.ContainsKey(voiceChannel.Id))
+                {
+                    _timers[voiceChannel.Id] = new Timer(async _ => await LeaveChannel(voiceChannel), null, TimeSpan.FromMinutes(3), Timeout.InfiniteTimeSpan);
+                }
+            }
+            else
+            {
+                if (voiceChannel == null || !_timers.ContainsKey(voiceChannel.Id)) 
+                    continue;
+                
+                await _timers[voiceChannel.Id].DisposeAsync();
+                _timers.Remove(voiceChannel.Id);
+            }
+        }
+    }
+
+    private async Task LeaveChannel(SocketVoiceChannel voiceChannel)
+    {
+        if (voiceChannel.ConnectedUsers.Count == 1 && voiceChannel.Users.Any(u => u.Id == _client.CurrentUser.Id))
+        {
+            await voiceChannel.DisconnectAsync();
+            await _timers[voiceChannel.Id].DisposeAsync();
+            _timers.Remove(voiceChannel.Id);
+        }
+    }
+}