Expose VoiceServerUpdate events (#984)

* Expose VoiceServerUpdate events

* Amend based on feedback

* Move this out of guild entity

* Fix namespace issue

* Adjust based on feedback #2

* Use cacheable instead

* Change based on feedback

src/Discord.Net.WebSocket/BaseSocketClient.Events.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Threading.Tasks;
 
 namespace Discord.WebSocket
@@ -165,6 +165,13 @@ namespace Discord.WebSocket
             remove { _userVoiceStateUpdatedEvent.Remove(value); }
         }
         internal readonly AsyncEvent<Func<SocketUser, SocketVoiceState, SocketVoiceState, Task>> _userVoiceStateUpdatedEvent = new AsyncEvent<Func<SocketUser, SocketVoiceState, SocketVoiceState, Task>>();
+        /// <summary> Fired when the bot connects to a Discord voice server. </summary>
+        public event Func<SocketVoiceServer, Task> VoiceServerUpdated
+        {
+            add { _voiceServerUpdatedEvent.Add(value);  }
+            remove { _voiceServerUpdatedEvent.Remove(value); }
+        }
+        internal readonly AsyncEvent<Func<SocketVoiceServer, Task>> _voiceServerUpdatedEvent = new AsyncEvent<Func<SocketVoiceServer, Task>>();
         /// <summary> Fired when the connected account is updated. </summary>
         public event Func<SocketSelfUser, SocketSelfUser, Task> CurrentUserUpdated {
             add { _selfUpdatedEvent.Add(value); }

src/Discord.Net.WebSocket/DiscordSocketClient.cs

@@ -1466,6 +1466,12 @@ namespace Discord.WebSocket
 
                                     var data = (payload as JToken).ToObject<VoiceServerUpdateEvent>(_serializer);
                                     var guild = State.GetGuild(data.GuildId);
+                                    var cacheable = new Cacheable<IGuild, ulong>(guild, data.GuildId, guild != null,
+                                        async () => await ApiClient.GetGuildAsync(data.GuildId).ConfigureAwait(false) as IGuild);
+
+                                    var voiceServer = new SocketVoiceServer(cacheable, data.GuildId, data.Endpoint, data.Token);
+                                    await TimedInvokeAsync(_voiceServerUpdatedEvent, nameof(UserVoiceStateUpdated), voiceServer).ConfigureAwait(false);
+
                                     if (guild != null)
                                     {
                                         string endpoint = data.Endpoint.Substring(0, data.Endpoint.LastIndexOf(':'));
@@ -1476,6 +1482,7 @@ namespace Discord.WebSocket
                                         await UnknownGuildAsync(type, data.GuildId).ConfigureAwait(false);
                                         return;
                                     }
+
                                 }
                                 break;
 

src/Discord.Net.WebSocket/SocketVoiceServer.cs

@@ -0,0 +1,21 @@
+using System.Diagnostics;
+
+namespace Discord.WebSocket
+{
+    [DebuggerDisplay(@"{DebuggerDisplay,nq}")]
+    public class SocketVoiceServer
+    {
+        public Cacheable<IGuild, ulong> Guild { get; private set; }
+        public string Endpoint { get; private set; }
+        public string Token { get; private set; }
+
+        internal SocketVoiceServer(Cacheable<IGuild, ulong> guild, ulong guildId, string endpoint, string token)
+        {
+            Guild = guild;
+            Endpoint = endpoint;
+            Token = token;
+        }
+
+        private string DebuggerDisplay => $"SocketVoiceServer ({Guild.Id})";
+    }
+}