[Feature] Polls (#2902)

no breakings hopefully

src/Discord.Net.Rest/Extensions/PollExtensions.cs

@@ -0,0 +1,61 @@
+using System.Collections.Immutable;
+using System.Linq;
+
+namespace Discord.Rest;
+
+internal static class PollExtensions
+{
+    public static API.Rest.CreatePollParams ToModel(this PollProperties poll)
+        => new()
+        {
+            AllowMultiselect = poll.AllowMultiselect,
+            Duration = poll.Duration,
+            LayoutType = poll.LayoutType,
+            Answers = poll.Answers.Select(x => new API.PollAnswer
+            {
+                PollMedia = new API.PollMedia
+                {
+                    Emoji = x.Emoji is not null
+                        ? new API.Emoji
+                        {
+                            Id = x.Emoji is Emote emote ? emote.Id : null,
+                            Name = x.Emoji is Emoji emoji ? emoji.Name : null,
+                        } : Optional<API.Emoji>.Unspecified,
+                    Text = x.Text,
+                }
+            }).ToArray(),
+            Question = new API.PollMedia
+            {
+                Emoji = poll.Question.Emoji is not null
+                    ? new API.Emoji
+                    {
+                        Id = poll.Question.Emoji is Emote emote ? emote.Id : null,
+                        Name = poll.Question.Emoji is Emoji emoji ? emoji.Name : null,
+                    }
+                    : Optional<API.Emoji>.Unspecified,
+                Text = poll.Question.Text,
+            },
+        };
+
+    public static Poll ToEntity(this API.Poll poll)
+        => new(
+            new PollMedia(poll.Question.Text,
+                poll.Question.Emoji.IsSpecified
+                    ? poll.Question.Emoji.Value.ToIEmote()
+                    : null),
+            poll.Answers.Select(x =>
+                new PollAnswer(
+                    x.AnswerId,
+                    new PollMedia(x.PollMedia.Text, x.PollMedia.Emoji.IsSpecified
+                        ? x.PollMedia.Emoji.Value.ToIEmote()
+                        : null))).ToImmutableArray(),
+            poll.Expiry,
+            poll.AllowMultiselect,
+            poll.LayoutType,
+            poll.PollResults.IsSpecified
+                ? new PollResults(
+                    poll.PollResults.Value.IsFinalized,
+                    poll.PollResults.Value.AnswerCounts.Select(x => new PollAnswerCounts(x.Id, x.Count, x.MeVoted)).ToImmutableArray())
+                : null
+            );
+}