Paginating reactions

src/Discord.Net.Core/Entities/Messages/EmbedBuilder.cs

@@ -231,7 +231,6 @@ namespace Discord
     {
         private string _name;
         private string _value;
-        private EmbedField _field;
         public const int MaxFieldNameLength = 256;
         public const int MaxFieldValueLength = 1024;
 

src/Discord.Net.Core/Entities/Messages/IUserMessage.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 
@@ -23,7 +23,7 @@ namespace Discord
         /// <summary> Removes all reactions from this message. </summary>
         Task RemoveAllReactionsAsync(RequestOptions options = null);
         /// <summary>  Gets all users that reacted to a message with a given emote </summary>
-        Task<IReadOnlyCollection<IUser>> GetReactionUsersAsync(IEmote emoji, int limit = 100, ulong? afterUserId = null, RequestOptions options = null);
+        IAsyncEnumerable<IReadOnlyCollection<IUser>> GetReactionUsersAsync(IEmote emoji, int limit = 100, ulong? afterUserId = null, RequestOptions options = null);
 
         /// <summary> Transforms this message's text into a human readable form by resolving its tags. </summary>
         string Resolve(

src/Discord.Net.Rest/API/Rest/GetReactionUsersParams.cs

@@ -1,4 +1,4 @@
-namespace Discord.API.Rest
+namespace Discord.API.Rest
 {
     internal class GetReactionUsersParams
     {

src/Discord.Net.Rest/Entities/Messages/MessageHelper.cs

@@ -46,13 +46,39 @@ namespace Discord.Rest
             await client.ApiClient.RemoveAllReactionsAsync(msg.Channel.Id, msg.Id, options);
         }
 
-        public static async Task<IReadOnlyCollection<IUser>> GetReactionUsersAsync(IMessage msg, IEmote emote,
+        public static IAsyncEnumerable<IReadOnlyCollection<IUser>> GetReactionUsersAsync(IMessage msg, IEmote emote,
             Action<GetReactionUsersParams> func, BaseDiscordClient client, RequestOptions options)
         {
             var args = new GetReactionUsersParams();
             func(args);
-            string emoji = (emote is Emote e ? $"{e.Name}:{e.Id}" : emote.Name);
-            return (await client.ApiClient.GetReactionUsersAsync(msg.Channel.Id, msg.Id, emoji, args, options).ConfigureAwait(false)).Select(u => RestUser.Create(client, u)).ToImmutableArray();
+
+            var emoji = (emote is Emote e ? $"{e.Name}:{e.Id}" : emote.Name);
+            return new PagedAsyncEnumerable<IUser>(
+                DiscordConfig.MaxUsersPerBatch,
+                async (info, ct) =>
+                {
+                    if (info.Position != null)
+                        args.AfterUserId = info.Position.Value;
+
+                    var models = await client.ApiClient.GetReactionUsersAsync(msg.Channel.Id, msg.Id, emoji, args, options).ConfigureAwait(false);
+                    var builder = ImmutableArray.CreateBuilder<IUser>();
+
+                    foreach (var model in models)
+                        builder.Add(RestUser.Create(client, model));
+
+                    return builder.ToImmutable();
+                },
+                nextPage: (info, lastPage) =>
+                {
+                    if (lastPage.Count != DiscordConfig.MaxUsersPerBatch)
+                        return false;
+
+                    info.Position = lastPage.OrderBy(u => u.Id).First().Id;
+                    return true;
+                },
+                count: args.Limit.Value
+            );
+
         }
 
         public static async Task PinAsync(IMessage msg, BaseDiscordClient client,

src/Discord.Net.Rest/Entities/Messages/RestUserMessage.cs

@@ -136,7 +136,7 @@ namespace Discord.Rest
             => MessageHelper.RemoveReactionAsync(this, user, emote, Discord, options);
         public Task RemoveAllReactionsAsync(RequestOptions options = null)
             => MessageHelper.RemoveAllReactionsAsync(this, Discord, options);
-        public Task<IReadOnlyCollection<IUser>> GetReactionUsersAsync(IEmote emote, int limit = 100, ulong? afterUserId = null, RequestOptions options = null)
+        public IAsyncEnumerable<IReadOnlyCollection<IUser>> GetReactionUsersAsync(IEmote emote, int limit = 100, ulong? afterUserId = null, RequestOptions options = null)
             => MessageHelper.GetReactionUsersAsync(this, emote, x => { x.Limit = limit; x.AfterUserId = afterUserId ?? Optional.Create<ulong>(); }, Discord, options);
 
 

src/Discord.Net.WebSocket/Entities/Messages/SocketUserMessage.cs

@@ -130,7 +130,7 @@ namespace Discord.WebSocket
             => MessageHelper.RemoveReactionAsync(this, user, emote, Discord, options);
         public Task RemoveAllReactionsAsync(RequestOptions options = null)
             => MessageHelper.RemoveAllReactionsAsync(this, Discord, options);
-        public Task<IReadOnlyCollection<IUser>> GetReactionUsersAsync(IEmote emote, int limit = 100, ulong? afterUserId = null, RequestOptions options = null)
+        public IAsyncEnumerable<IReadOnlyCollection<IUser>> GetReactionUsersAsync(IEmote emote, int limit = 100, ulong? afterUserId = null, RequestOptions options = null)
             => MessageHelper.GetReactionUsersAsync(this, emote, x => { x.Limit = limit; x.AfterUserId = afterUserId ?? Optional.Create<ulong>(); }, Discord, options);
 
         public Task PinAsync(RequestOptions options = null)