Resolve permissions for category

src/Discord.Net.WebSocket/Entities/Channels/SocketCategoryChannel.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
@@ -15,7 +15,9 @@ namespace Discord.WebSocket
     public class SocketCategoryChannel : SocketGuildChannel, ICategoryChannel
     {
         public override IReadOnlyCollection<SocketGuildUser> Users
-            => throw new NotSupportedException();
+            => Guild.Users.Where(x => Permissions.GetValue(
+               Permissions.ResolveChannel(Guild, x, this, Permissions.ResolveGuild(Guild, x)),
+               ChannelPermission.ViewChannel)).ToImmutableArray();
 
         public IReadOnlyCollection<SocketGuildChannel> Channels
             => Guild.Channels.Where(x => x.CategoryId == Id).ToImmutableArray();
@@ -31,14 +33,28 @@ namespace Discord.WebSocket
             return entity;
         }
 
+        //Users
+        public override SocketGuildUser GetUser(ulong id)
+        {
+            var user = Guild.GetUser(id);
+            if (user != null)
+            {
+                var guildPerms = Permissions.ResolveGuild(Guild, user);
+                var channelPerms = Permissions.ResolveChannel(Guild, user, this, guildPerms);
+                if (Permissions.GetValue(channelPerms, ChannelPermission.ViewChannel))
+                    return user;
+            }
+            return null;
+        }
+
         private string DebuggerDisplay => $"{Name} ({Id}, Category)";
-        internal new SocketCategoryChannel Clone() => MemberwiseClone() as SocketCategoryChannel;
+        internal new SocketCategoryChannel Clone() => MemberwiseClone() as SocketCategoryChannel;       
 
         // IGuildChannel
         IAsyncEnumerable<IReadOnlyCollection<IGuildUser>> IGuildChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
-            => throw new NotSupportedException();
+            => ImmutableArray.Create<IReadOnlyCollection<IGuildUser>>(Users).ToAsyncEnumerable();
         Task<IGuildUser> IGuildChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options)
-            => throw new NotSupportedException();
+            => Task.FromResult<IGuildUser>(GetUser(id));
         Task<IInviteMetadata> IGuildChannel.CreateInviteAsync(int? maxAge, int? maxUses, bool isTemporary, bool isUnique, RequestOptions options)
             => throw new NotSupportedException();
         Task<IReadOnlyCollection<IInviteMetadata>> IGuildChannel.GetInvitesAsync(RequestOptions options)
@@ -46,8 +62,8 @@ namespace Discord.WebSocket
 
         //IChannel
         IAsyncEnumerable<IReadOnlyCollection<IUser>> IChannel.GetUsersAsync(CacheMode mode, RequestOptions options)
-            => throw new NotSupportedException();
+            => ImmutableArray.Create<IReadOnlyCollection<IGuildUser>>(Users).ToAsyncEnumerable();
         Task<IUser> IChannel.GetUserAsync(ulong id, CacheMode mode, RequestOptions options)
-            => throw new NotSupportedException();
+            => Task.FromResult<IUser>(GetUser(id));
     }
 }