Switch from Discord.Net to Remora.Discord

- Remove typing event support.
- Remove Message.Context as it was used only for that
- .ToAsyncEnumerable() seemed to have relied on a sub-library of Discord.Net. Removed it's usage in DefaultIOManager.

src/Tgstation.Server.Host/Components/Chat/ChatManager.cs

@@ -761,7 +761,7 @@ namespace Tgstation.Server.Host.Components.Chat
 					{
 						messageTasks.Remove(undisposedMessageTaskKvp.Key);
 						if (undisposedMessageTaskKvp.Value.IsCompleted)
-							(await undisposedMessageTaskKvp.Value.ConfigureAwait(false))?.Context?.Dispose();
+							await undisposedMessageTaskKvp.Value.ConfigureAwait(false);
 					}
 
 					// add new ones
@@ -786,7 +786,6 @@ namespace Tgstation.Server.Host.Components.Chat
 					foreach (var completedMessageTaskKvp in messageTasks.Where(x => x.Value.IsCompleted).ToList())
 					{
 						var message = await completedMessageTaskKvp.Value.ConfigureAwait(false);
-						using var messageContext = message?.Context;
 						var messageNumber = Interlocked.Increment(ref messagesProcessed);
 						using (LogContext.PushProperty("ChatMessage", messageNumber))
 							await ProcessMessage(completedMessageTaskKvp.Key, message, cancellationToken).ConfigureAwait(false);

src/Tgstation.Server.Host/Components/Chat/Message.cs

@@ -1,6 +1,4 @@
-using System;
-
-namespace Tgstation.Server.Host.Components.Chat.Providers
+namespace Tgstation.Server.Host.Components.Chat.Providers
 {
 	/// <summary>
 	/// Represents a message recieved by a <see cref="IProvider"/>.
@@ -16,10 +14,5 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// The <see cref="ChatUser"/> who sent the <see cref="Message"/>.
 		/// </summary>
 		public ChatUser User { get; set; }
-
-		/// <summary>
-		/// The <see cref="IDisposable"/> that should be <see cref="IDisposable.Dispose"/>d once the <see cref="Message"/> is processed.
-		/// </summary>
-		public IDisposable Context { get; set; }
 	}
 }

src/Tgstation.Server.Host/Components/Chat/Providers/DiscordForwardingResponder.cs

@@ -0,0 +1,33 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Remora.Discord.API.Abstractions.Gateway.Events;
+using Remora.Discord.Gateway.Responders;
+using Remora.Results;
+
+namespace Tgstation.Server.Host.Components.Chat.Providers
+{
+	/// <summary>
+	/// An <see cref="IResponder{TGatewayEvent}"/> that forwards to another <see cref="targetResponder"/>.
+	/// </summary>
+	sealed class DiscordForwardingResponder : IDiscordResponders
+	{
+		/// <summary>
+		/// The <see cref="IResponder{TGatewayEvent}"/> to forward the event to.
+		/// </summary>
+		readonly IDiscordResponders targetResponder;
+
+		/// <summary>
+		/// Initializes a new instance of the <see cref="DiscordForwardingResponder"/> class.
+		/// </summary>
+		/// <param name="targetResponder">The value of <see cref="targetResponder"/>.</param>
+		public DiscordForwardingResponder(IDiscordResponders targetResponder)
+		{
+			this.targetResponder = targetResponder ?? throw new ArgumentNullException(nameof(targetResponder));
+		}
+
+		/// <inheritdoc />
+		public Task<Result> RespondAsync(IMessageCreate gatewayEvent, CancellationToken ct) => targetResponder.RespondAsync(gatewayEvent, ct);
+	}
+}

src/Tgstation.Server.Host/Components/Chat/Providers/DiscordProvider.cs

@@ -1,12 +1,20 @@
 using System;
 using System.Collections.Generic;
+using System.Drawing;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 
-using Discord;
-using Discord.WebSocket;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
+using Remora.Discord.API.Abstractions.Gateway.Events;
+using Remora.Discord.API.Abstractions.Objects;
+using Remora.Discord.API.Abstractions.Rest;
+using Remora.Discord.API.Objects;
+using Remora.Discord.Core;
+using Remora.Discord.Gateway;
+using Remora.Discord.Gateway.Extensions;
+using Remora.Results;
 
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Host.Jobs;
@@ -18,10 +26,10 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 	/// <summary>
 	/// <see cref="IProvider"/> for the Discord app.
 	/// </summary>
-	sealed class DiscordProvider : Provider
+	sealed class DiscordProvider : Provider, IDiscordResponders
 	{
 		/// <inheritdoc />
-		public override bool Connected => client.ConnectionState != ConnectionState.Disconnected;
+		public override bool Connected => gatewayTask?.IsCompleted == false;
 
 		/// <inheritdoc />
 		public override string BotMention
@@ -30,7 +38,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			{
 				if (!Connected)
 					throw new InvalidOperationException("Provider not connected");
-				return NormalizeMentions(client.CurrentUser.Mention);
+				return NormalizeMentions($"<@{currentUserId}>");
 			}
 		}
 
@@ -40,20 +48,15 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		readonly IAssemblyInformationProvider assemblyInformationProvider;
 
 		/// <summary>
-		/// The <see cref="DiscordSocketClient"/> for the <see cref="DiscordProvider"/>.
+		/// The <see cref="ServiceProvider"/> containing Discord services.
 		/// </summary>
-		readonly DiscordSocketClient client;
+		readonly ServiceProvider serviceProvider;
 
 		/// <summary>
-		/// <see cref="List{T}"/> of mapped <see cref="ITextChannel"/> <see cref="IEntity{TId}.Id"/>s.
+		/// <see cref="List{T}"/> of mapped channel <see cref="Snowflake"/>s.
 		/// </summary>
 		readonly List<ulong> mappedChannels;
 
-		/// <summary>
-		/// The Discord bot token.
-		/// </summary>
-		readonly string botToken;
-
 		/// <summary>
 		/// <see cref="bool"/> to enable based mode. Will auto reply with a youtube link to a video that says "based on the hardware that's installed in it" to anyone saying 'based on what?' case-insensitive.
 		/// </summary>
@@ -64,6 +67,21 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// </summary>
 		readonly DiscordDMOutputDisplayType outputDisplayType;
 
+		/// <summary>
+		/// The <see cref="CancellationTokenSource"/> for the <see cref="gatewayTask"/>.
+		/// </summary>
+		CancellationTokenSource gatewayCts;
+
+		/// <summary>
+		/// The <see cref="Task"/> representing the lifetime of the client.
+		/// </summary>
+		Task<Result> gatewayTask;
+
+		/// <summary>
+		/// The bot's <see cref="Snowflake"/>.
+		/// </summary>
+		Snowflake currentUserId;
+
 		/// <summary>
 		/// Normalize a discord mention string.
 		/// </summary>
@@ -72,15 +90,15 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		static string NormalizeMentions(string fromDiscord) => fromDiscord.Replace("<@!", "<@", StringComparison.Ordinal);
 
 		/// <summary>
-		/// Create a <see cref="List{T}"/> of <see cref="EmbedFieldBuilder"/>s for a discord update embed.
+		/// Create a <see cref="List{T}"/> of <see cref="IEmbedField"/>s for a discord update embed.
 		/// </summary>
 		/// <param name="revisionInformation">The <see cref="RevisionInformation"/> of the deployment.</param>
 		/// <param name="byondVersion">The BYOND <see cref="Version"/> of the deployment.</param>
 		/// <param name="gitHubOwner">The repository GitHub owner, if any.</param>
 		/// <param name="gitHubRepo">The repository GitHub name, if any.</param>
 		/// <param name="localCommitPushed"><see langword="true"/> if the local deployment commit was pushed to the remote repository.</param>
-		/// <returns>A new <see cref="List{T}"/> of <see cref="EmbedFieldBuilder"/>s to use.</returns>
-		static List<EmbedFieldBuilder> BuildUpdateEmbedFields(
+		/// <returns>A new <see cref="List{T}"/> of <see cref="IEmbedField"/>s to use.</returns>
+		static List<IEmbedField> BuildUpdateEmbedFields(
 			Models.RevisionInformation revisionInformation,
 			Version byondVersion,
 			string gitHubOwner,
@@ -88,39 +106,32 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			bool localCommitPushed)
 		{
 			bool gitHub = gitHubOwner != null && gitHubRepo != null;
-			var fields = new List<EmbedFieldBuilder>
+			var fields = new List<IEmbedField>
 			{
-				new EmbedFieldBuilder
-				{
-					Name = "BYOND Version",
-					Value = $"{byondVersion.Major}.{byondVersion.Minor}{(byondVersion.Build > 0 ? $".{byondVersion.Build}" : String.Empty)}",
-					IsInline = true,
-				},
-				new EmbedFieldBuilder
-				{
-					Name = "Local Commit",
-					Value = localCommitPushed && gitHub
+				new EmbedField(
+					"BYOND Version",
+					$"{byondVersion.Major}.{byondVersion.Minor}{(byondVersion.Build > 0 ? $".{byondVersion.Build}" : String.Empty)}",
+					true),
+				new EmbedField(
+					"Local Commit",
+					localCommitPushed && gitHub
 						? $"[{revisionInformation.CommitSha.Substring(0, 7)}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{revisionInformation.CommitSha})"
 						: revisionInformation.CommitSha.Substring(0, 7),
-					IsInline = true,
-				},
-				new EmbedFieldBuilder
-				{
-					Name = "Branch Commit",
-					Value = gitHub
+					true),
+				new EmbedField(
+					"Branch Commit",
+					gitHub
 						? $"[{revisionInformation.OriginCommitSha.Substring(0, 7)}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{revisionInformation.OriginCommitSha})"
 						: revisionInformation.OriginCommitSha.Substring(0, 7),
-					IsInline = true,
-				},
+					true),
 			};
 
 			fields.AddRange((revisionInformation.ActiveTestMerges ?? Enumerable.Empty<RevInfoTestMerge>())
 				.Select(x => x.TestMerge)
-				.Select(x => new EmbedFieldBuilder
-				{
-					Name = $"#{x.Number}",
-					Value = $"[{x.TitleAtMerge}]({x.Url}) by _[@{x.Author}](https://github.com/{x.Author})_{Environment.NewLine}Commit: [{x.TargetCommitSha.Substring(0, 7)}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{x.TargetCommitSha}){(String.IsNullOrWhiteSpace(x.Comment) ? String.Empty : $"{Environment.NewLine}_**{x.Comment}**_")}",
-				}));
+				.Select(x => new EmbedField(
+					$"#{x.Number}",
+					$"[{x.TitleAtMerge}]({x.Url}) by _[@{x.Author}](https://github.com/{x.Author})_{Environment.NewLine}Commit: [{x.TargetCommitSha.Substring(0, 7)}](https://github.com/{gitHubOwner}/{gitHubRepo}/commit/{x.TargetCommitSha}){(String.IsNullOrWhiteSpace(x.Comment) ? String.Empty : $"{Environment.NewLine}_**{x.Comment}**_")}",
+					false)));
 
 			return fields;
 		}
@@ -141,25 +152,32 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		{
 			this.assemblyInformationProvider = assemblyInformationProvider ?? throw new ArgumentNullException(nameof(assemblyInformationProvider));
 
+			mappedChannels = new List<ulong>();
+
 			var csb = new DiscordConnectionStringBuilder(chatBot.ConnectionString);
-			botToken = csb.BotToken;
+			var botToken = csb.BotToken;
 			basedMeme = csb.BasedMeme;
 			outputDisplayType = csb.DMOutputDisplay;
 
-			client = new DiscordSocketClient();
-			client.MessageReceived += Client_MessageReceived;
-			mappedChannels = new List<ulong>();
+			serviceProvider = new ServiceCollection()
+				.AddDiscordGateway(serviceProvider => botToken)
+				.AddSingleton<IDiscordResponders>(serviceProvider => this)
+				.AddResponder<DiscordForwardingResponder>()
+				.BuildServiceProvider();
 		}
 
 		/// <inheritdoc />
 		public override async ValueTask DisposeAsync()
 		{
 			await base.DisposeAsync().ConfigureAwait(false);
-			client.Dispose();
+			await serviceProvider.DisposeAsync().ConfigureAwait(false);
+
+			// this line is purely here to shutup CA2213
+			gatewayCts?.Dispose();
 		}
 
 		/// <inheritdoc />
-		public override Task<IReadOnlyCollection<ChannelRepresentation>> MapChannels(IEnumerable<Api.Models.ChatChannel> channels, CancellationToken cancellationToken)
+		public override async Task<IReadOnlyCollection<ChannelRepresentation>> MapChannels(IEnumerable<Api.Models.ChatChannel> channels, CancellationToken cancellationToken)
 		{
 			if (channels == null)
 				throw new ArgumentNullException(nameof(channels));
@@ -167,10 +185,19 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			if (!Connected)
 			{
 				Logger.LogWarning("Cannot map channels, provider disconnected!");
-				return Task.FromResult<IReadOnlyCollection<ChannelRepresentation>>(Array.Empty<ChannelRepresentation>());
+				return Array.Empty<ChannelRepresentation>();
 			}
 
-			ChannelRepresentation GetModelChannelFromDBChannel(Api.Models.ChatChannel channelFromDB)
+			var usersClient = serviceProvider.GetRequiredService<IDiscordRestUserAPI>();
+			var currentUserResponse = await usersClient.GetCurrentUserAsync(cancellationToken).ConfigureAwait(false);
+
+			if (!currentUserResponse.IsSuccess)
+			{
+				Logger.LogWarning("Error retrieving current Discord user: {0}", currentUserResponse.Error.Message);
+				return Array.Empty<ChannelRepresentation>();
+			}
+
+			async Task<ChannelRepresentation> GetModelChannelFromDBChannel(Api.Models.ChatChannel channelFromDB)
 			{
 				if (!channelFromDB.DiscordChannelId.HasValue)
 					throw new InvalidOperationException("ChatChannel missing DiscordChannelId!");
@@ -181,22 +208,44 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 				string friendlyName;
 				if (channelId == 0)
 				{
-					connectionName = client.CurrentUser.Username;
+					connectionName = currentUserResponse.Entity.Username;
 					friendlyName = "(Unmapped accessible channels)";
 					discordChannelId = 0;
 				}
 				else
 				{
-					var discordChannel = client.GetChannel(channelId);
-					if (!(discordChannel is ITextChannel textChannel))
+					var channelsClient = serviceProvider.GetRequiredService<IDiscordRestChannelAPI>();
+					var discordChannelResponse = await channelsClient.GetChannelAsync(new Snowflake(channelId), cancellationToken);
+					if (!discordChannelResponse.IsSuccess)
 					{
-						Logger.LogWarning("Cound not map channel {0}! Incorrect type: {1}", channelId, discordChannel?.GetType());
+						Logger.LogWarning("Error retrieving discord channel {0}: {1}", channelId, discordChannelResponse.Error.Message);
 						return null;
 					}
 
-					discordChannelId = textChannel.Id;
-					connectionName = textChannel.Guild.Name;
-					friendlyName = textChannel.Name;
+					if (discordChannelResponse.Entity.Type != ChannelType.GuildText)
+					{
+						Logger.LogWarning("Cound not map channel {0}! Incorrect type: {1}", channelId, discordChannelResponse.Entity.Type);
+						return null;
+					}
+
+					discordChannelId = discordChannelResponse.Entity.ID.Value;
+					friendlyName = discordChannelResponse.Entity.Name.Value;
+
+					var guildsClient = serviceProvider.GetRequiredService<IDiscordRestGuildAPI>();
+					var guildsResponse = await guildsClient.GetGuildAsync(
+						discordChannelResponse.Entity.GuildID.Value,
+						false,
+						cancellationToken);
+					if (!guildsResponse.IsSuccess)
+					{
+						Logger.LogWarning(
+							"Error retrieving discord guild {0}: {1}",
+							discordChannelResponse.Entity.GuildID.Value,
+							discordChannelResponse.Error.Message);
+						return null;
+					}
+
+					connectionName = guildsResponse.Entity.Name;
 				}
 
 				var channelModel = new ChannelRepresentation
@@ -208,13 +257,21 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 					IsPrivateChannel = false,
 					Tag = channelFromDB.Tag,
 				};
+
 				Logger.LogTrace("Mapped channel {0}: {1}", channelModel.RealId, channelModel.FriendlyName);
 				return channelModel;
 			}
 
-			var enumerator = channels
+			var tasks = channels
 				.Select(x => GetModelChannelFromDBChannel(x))
-				.Where(x => x != null).ToList();
+				.Where(x => x != null)
+				.ToList();
+
+			await Task.WhenAll(tasks);
+
+			var enumerator = tasks
+				.Select(x => x.Result)
+				.ToList();
 
 			lock (mappedChannels)
 			{
@@ -222,57 +279,64 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 				mappedChannels.AddRange(enumerator.Select(x => x.RealId));
 			}
 
-			return Task.FromResult<IReadOnlyCollection<ChannelRepresentation>>(enumerator);
+			return enumerator;
 		}
 
 		/// <inheritdoc />
 		public override async Task SendMessage(ulong channelId, string message, CancellationToken cancellationToken)
 		{
-			var requestOptions = new RequestOptions
+			var channelsClient = serviceProvider.GetRequiredService<IDiscordRestChannelAPI>();
+			async Task SendToChannel(Snowflake channelId)
 			{
-				CancelToken = cancellationToken,
-				Timeout = 10000, // prevent stupid long hold ups from this
-			};
+				var result = await channelsClient.CreateMessageAsync(
+					channelId,
+					message,
+					ct: cancellationToken);
 
-			Task SendToChannel(IMessageChannel channel) => channel.SendMessageAsync(
-				message,
-				false,
-				null,
-				requestOptions);
+				if (!result.IsSuccess)
+					Logger.LogWarning(
+						"Failed to send to channel {0}: {1}",
+						channelId,
+						result.Error.Message);
+			}
 
 			try
 			{
 				if (channelId == 0)
 				{
-					var unmappedTextChannels = client
-						.Guilds
-						.SelectMany(x => x.TextChannels);
+					var usersClient = serviceProvider.GetRequiredService<IDiscordRestUserAPI>();
+					var currentGuildsResponse = await usersClient.GetCurrentUserGuildsAsync(ct: cancellationToken).ConfigureAwait(false);
+					if (!currentGuildsResponse.IsSuccess)
+					{
+						Logger.LogWarning(
+							"Error retrieving current discord guilds: {0}",
+							currentGuildsResponse.Error.Message);
+						return;
+					}
+
+					var unmappedTextChannels = currentGuildsResponse
+						.Entity
+						.SelectMany(x => x.Channels.Value);
 
 					lock (mappedChannels)
-						unmappedTextChannels = unmappedTextChannels.Where(x => !mappedChannels.Contains(x.Id));
+						unmappedTextChannels = unmappedTextChannels
+							.Where(x => !mappedChannels.Contains(x.ID.Value))
+							.ToList();
 
 					// discord API confirmed weak boned: https://stackoverflow.com/a/52462336
-					var channelCount = 0UL;
-					var tasks = unmappedTextChannels
-						.Select(x =>
-						{
-							++channelCount;
-							return SendToChannel(x);
-						});
-
-					if (channelCount > 0)
+					if (unmappedTextChannels.Any())
 					{
-						Logger.LogTrace("Dispatched to {0} unmapped channels...", channelCount);
-						await Task.WhenAll(tasks).ConfigureAwait(false);
+						Logger.LogTrace("Dispatching to {0} unmapped channels...", unmappedTextChannels.Count());
+						await Task.WhenAll(
+							unmappedTextChannels.Select(
+								x => SendToChannel(x.ID)))
+							.ConfigureAwait(false);
 					}
 
 					return;
 				}
 
-				if (!(client.GetChannel(channelId) is IMessageChannel channel))
-					return;
-
-				await SendToChannel(channel).ConfigureAwait(false);
+				await SendToChannel(new Snowflake(channelId)).ConfigureAwait(false);
 			}
 			catch (Exception e)
 			{
@@ -283,6 +347,7 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		}
 
 		/// <inheritdoc />
+#pragma warning disable CA1506
 		public override async Task<Func<string, string, Task>> SendUpdateMessage(
 			Models.RevisionInformation revisionInformation,
 			Version byondVersion,
@@ -296,51 +361,53 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 			localCommitPushed |= revisionInformation.CommitSha == revisionInformation.OriginCommitSha;
 
 			var fields = BuildUpdateEmbedFields(revisionInformation, byondVersion, gitHubOwner, gitHubRepo, localCommitPushed);
-			var builder = new EmbedBuilder
+			var embed = new Embed
 			{
-				Author = new EmbedAuthorBuilder
+				Author = new EmbedAuthor
 				{
 					Name = assemblyInformationProvider.VersionPrefix,
 					Url = "https://github.com/tgstation/tgstation-server",
 					IconUrl = "https://avatars0.githubusercontent.com/u/1363778?s=280&v=4",
 				},
-				Color = Color.Gold,
+				Colour = Color.FromArgb(0xF1, 0xC4, 0x0F),
 				Description = "TGS has begun deploying active repository code to production.",
 				Fields = fields,
 				Title = "Code Deployment",
-				Footer = new EmbedFooterBuilder
-				{
-					Text = $"In progress...{(estimatedCompletionTime.HasValue ? " ETA" : String.Empty)}",
-				},
-				Timestamp = estimatedCompletionTime,
+				Footer = new EmbedFooter(
+					$"In progress...{(estimatedCompletionTime.HasValue ? " ETA" : String.Empty)}"),
+				Timestamp = estimatedCompletionTime ?? default,
 			};
 
 			Logger.LogTrace("Attempting to post deploy embed to channel {0}...", channelId);
-			if (!(client.GetChannel(channelId) is IMessageChannel channel))
-			{
-				Logger.LogTrace("Channel ID {0} does not exist or is not an IMessageChannel!", channelId);
-				return (errorMessage, dreamMakerOutput) => Task.CompletedTask;
-			}
+			var channelsClient = serviceProvider.GetRequiredService<IDiscordRestChannelAPI>();
 
-			var message = await channel.SendMessageAsync(
+			var messageResponse = await channelsClient.CreateMessageAsync(
+				new Snowflake(channelId),
 				"DM: Deployment in Progress...",
-				false,
-				builder.Build(),
-				new RequestOptions
-				{
-					CancelToken = cancellationToken,
-				})
+				embeds: new List<IEmbed> { embed },
+				ct: cancellationToken)
 				.ConfigureAwait(false);
 
+			if (!messageResponse.IsSuccess)
+				Logger.LogWarning("Failed to post deploy embed to channel {0}: {1}", channelId, messageResponse.Error.Message);
+
 			return async (errorMessage, dreamMakerOutput) =>
 			{
 				var completionString = errorMessage == null ? "Succeeded" : "Failed";
-				builder.Footer.Text = completionString;
-				builder.Color = errorMessage == null ? Color.Green : Color.Red;
-				builder.Timestamp = DateTimeOffset.UtcNow;
-				builder.Description = errorMessage == null
+
+				embed = new Embed
+				{
+					Author = embed.Author,
+					Colour = errorMessage == null ? Color.Green : Color.Red,
+					Description = errorMessage == null
 					? "The deployment completed successfully and will be available at the next server reboot."
-					: "The deployment failed.";
+					: "The deployment failed.",
+					Fields = fields,
+					Title = embed.Title,
+					Footer = new EmbedFooter(
+						completionString),
+					Timestamp = DateTimeOffset.UtcNow,
+				};
 
 				var showDMOutput = outputDisplayType switch
 				{
@@ -352,83 +419,188 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 
 				if (dreamMakerOutput != null)
 				{
-					showDMOutput = showDMOutput && dreamMakerOutput.Length < EmbedFieldBuilder.MaxFieldValueLength - (6 + Environment.NewLine.Length);
+					// https://github.com/discord-net/Discord.Net/blob/8349cd7e1eb92e9a3baff68082c30a7b43e8e9b7/src/Discord.Net.Core/Entities/Messages/EmbedBuilder.cs#L431
+					const int MaxFieldValueLength = 1024;
+					showDMOutput = showDMOutput && dreamMakerOutput.Length < MaxFieldValueLength - (6 + Environment.NewLine.Length);
 					if (showDMOutput)
-						builder.AddField(new EmbedFieldBuilder
-						{
-							Name = "DreamMaker Output",
-							Value = $"```{Environment.NewLine}{dreamMakerOutput}{Environment.NewLine}```",
-						});
+						fields.Add(new EmbedField(
+							"DreamMaker Output",
+							$"```{Environment.NewLine}{dreamMakerOutput}{Environment.NewLine}```",
+							false));
 				}
 
 				if (errorMessage != null)
-					builder.AddField(new EmbedFieldBuilder
-					{
-						Name = "Error Message",
-						Value = errorMessage,
-					});
+					fields.Add(new EmbedField(
+						"Error Message",
+						errorMessage,
+						false));
 
 				var updatedMessage = $"DM: Deployment {completionString}!";
-				try
+
+				async Task CreateUpdatedMessage()
 				{
-					await message.ModifyAsync(
-						props =>
-						{
-							props.Content = updatedMessage;
-							props.Embed = builder.Build();
-						})
+					var createUpdatedMessageResponse = await channelsClient.CreateMessageAsync(
+						new Snowflake(channelId),
+						updatedMessage,
+						embeds: new List<IEmbed> { embed },
+						ct: cancellationToken)
 						.ConfigureAwait(false);
+
+					if (!createUpdatedMessageResponse.IsSuccess)
+						Logger.LogWarning(
+							"Creating updated deploy embed failed! Error: {0}",
+							createUpdatedMessageResponse.Error.Message);
 				}
-				catch (Exception ex)
+
+				if (!messageResponse.IsSuccess)
+					await CreateUpdatedMessage();
+				else
 				{
-					Logger.LogWarning(ex, "Updating deploy embed {0} failed, attempting new post!", message.Id);
-					try
+					var editResponse = await channelsClient.EditMessageAsync(
+						new Snowflake(channelId),
+						messageResponse.Entity.ID,
+						updatedMessage,
+						embeds: new List<IEmbed> { embed },
+						ct: cancellationToken)
+						.ConfigureAwait(false);
+
+					if (!editResponse.IsSuccess)
 					{
-						await channel.SendMessageAsync(
-							updatedMessage,
-							false,
-							builder.Build())
-							.ConfigureAwait(false);
-					}
-					catch (Exception ex2)
-					{
-						Logger.LogWarning(ex2, "Posting completion deploy embed failed!");
+						Logger.LogWarning(
+							"Updating deploy embed {0} failed, attempting new post! Error: {1}",
+							messageResponse.Entity.ID,
+							editResponse.Error.Message);
+						await CreateUpdatedMessage();
 					}
 				}
 			};
 		}
+		#pragma warning restore CA1506
+
+		/// <inheritdoc />
+		public async Task<Result> RespondAsync(IMessageCreate messageCreateEvent, CancellationToken cancellationToken)
+		{
+			if ((messageCreateEvent.Type != MessageType.Default
+				&& messageCreateEvent.Type != MessageType.InlineReply)
+				|| messageCreateEvent.Author.ID == currentUserId)
+				return Result.FromSuccess();
+
+			if (basedMeme && messageCreateEvent.Content.Equals("Based on what?", StringComparison.OrdinalIgnoreCase))
+			{
+				// DCT: None available
+				await SendMessage(
+					messageCreateEvent.ChannelID.Value,
+					"https://youtu.be/LrNu-SuFF_o",
+					default)
+					.ConfigureAwait(false);
+				return Result.FromSuccess();
+			}
+
+			var channelsClient = serviceProvider.GetRequiredService<IDiscordRestChannelAPI>();
+			var channelResponse = await channelsClient.GetChannelAsync(messageCreateEvent.ChannelID, cancellationToken).ConfigureAwait(false);
+			if (!channelResponse.IsSuccess)
+			{
+				Logger.LogWarning(
+					"Failed to get channel {0} in response to message {1}!",
+					messageCreateEvent.ChannelID,
+					messageCreateEvent.ID);
+
+				// we'll handle the errors ourselves
+				return Result.FromSuccess();
+			}
+
+			var pm = channelResponse.Entity.Type == ChannelType.DM || channelResponse.Entity.Type == ChannelType.GroupDM;
+			var shouldNotAnswer = !pm;
+			if (shouldNotAnswer)
+				lock (mappedChannels)
+					shouldNotAnswer = !mappedChannels.Contains(messageCreateEvent.ChannelID.Value);
+
+			var content = NormalizeMentions(messageCreateEvent.Content);
+			var mentionedUs = messageCreateEvent.Mentions.Any(x => x.ID == currentUserId)
+				|| (!shouldNotAnswer && content.Split(' ').First().Equals(ChatManager.CommonMention, StringComparison.OrdinalIgnoreCase));
+
+			if (shouldNotAnswer)
+			{
+				if (mentionedUs)
+					Logger.LogTrace(
+						"Ignoring mention from {0} ({1}) by {2} ({3}). Channel not mapped!",
+						messageCreateEvent.ChannelID,
+						channelResponse.Entity.Name,
+						messageCreateEvent.Author.ID,
+						messageCreateEvent.Author.Username);
+
+				return Result.FromSuccess();
+			}
+
+			string guildName = "UNKNOWN";
+			if (!pm)
+			{
+				var guildsClient = serviceProvider.GetRequiredService<IDiscordRestGuildAPI>();
+				var messageGuildResponse = await guildsClient.GetGuildAsync(messageCreateEvent.GuildID.Value, false, cancellationToken).ConfigureAwait(false);
+				if (messageGuildResponse.IsSuccess)
+					guildName = messageGuildResponse.Entity.Name;
+				else
+					Logger.LogWarning(
+						"Failed to get channel {0} in response to message {1}!",
+						messageCreateEvent.ChannelID,
+						messageCreateEvent.ID);
+			}
+
+			var result = new Message
+			{
+				Content = content,
+				User = new ChatUser
+				{
+					RealId = messageCreateEvent.Author.ID.Value,
+					Channel = new ChannelRepresentation
+					{
+						RealId = messageCreateEvent.ChannelID.Value,
+						IsPrivateChannel = pm,
+						ConnectionName = pm ? messageCreateEvent.Author.Username : guildName,
+						FriendlyName = channelResponse.Entity.Name.Value,
+
+						// isAdmin and Tag populated by manager
+					},
+					FriendlyName = messageCreateEvent.Author.Username,
+					Mention = NormalizeMentions($"<@{messageCreateEvent.Author.ID}>"),
+				},
+			};
+
+			EnqueueMessage(result);
+			return Result.FromSuccess();
+		}
 
 		/// <inheritdoc />
 		protected override async Task Connect(CancellationToken cancellationToken)
 		{
 			try
 			{
-				await client.LoginAsync(TokenType.Bot, botToken, true).ConfigureAwait(false);
+				if (gatewayCts != null)
+					throw new InvalidOperationException("Discord gateway still active!");
 
-				Logger.LogTrace("Logged in.");
-				cancellationToken.ThrowIfCancellationRequested();
+				gatewayCts = new CancellationTokenSource();
 
-				var channelsAvailable = new TaskCompletionSource<object>();
-				Task ReadyCallback()
+				var gatewayCancellationToken = gatewayCts.Token;
+				var gatewayClient = serviceProvider.GetRequiredService<DiscordGatewayClient>();
+
+				// reconnects keep happening until we stop or it faults, our auto-reconnector will handle the latter
+				gatewayTask = gatewayClient.RunAsync(gatewayCancellationToken);
+
+				var userClient = serviceProvider.GetRequiredService<IDiscordRestUserAPI>();
+
+				using var localCombinedCts = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken, gatewayCancellationToken);
+				var currentUserResult = await userClient.GetCurrentUserAsync(localCombinedCts.Token).ConfigureAwait(false);
+				if (!currentUserResult.IsSuccess)
 				{
-					channelsAvailable.TrySetResult(null);
-					return Task.CompletedTask;
+					Logger.LogWarning("Unable to retrieve current user: {0}", currentUserResult.Error.Message);
+
+					// will handle cleanup
+					await DisconnectImpl(cancellationToken).ConfigureAwait(false);
+
+					throw new JobException(ErrorCode.ChatCannotConnectProvider);
 				}
 
-				client.Ready += ReadyCallback;
-				try
-				{
-					await client.StartAsync().ConfigureAwait(false);
-
-					Logger.LogTrace("Started.");
-
-					using (cancellationToken.Register(() => channelsAvailable.SetCanceled()))
-						await channelsAvailable.Task.ConfigureAwait(false);
-				}
-				finally
-				{
-					client.Ready -= ReadyCallback;
-				}
+				currentUserId = currentUserResult.Entity.ID;
 			}
 			catch (OperationCanceledException)
 			{
@@ -443,153 +615,17 @@ namespace Tgstation.Server.Host.Components.Chat.Providers
 		/// <inheritdoc />
 		protected override async Task DisconnectImpl(CancellationToken cancellationToken)
 		{
-			try
-			{
-				cancellationToken.ThrowIfCancellationRequested();
-				var disconnectTcs = new TaskCompletionSource<object>();
-				Task DisconnectCallback(Exception exception)
-				{
-					if (exception != null)
-						Logger.LogTrace(exception, "Error stopping discord client!");
+			if (gatewayCts == null)
+				throw new InvalidOperationException("Discord gateway is not active!");
 
-					disconnectTcs.TrySetResult(null);
-					return Task.CompletedTask;
-				}
+			gatewayCts.Cancel();
+			var gatewayResult = await gatewayTask.ConfigureAwait(false);
+			gatewayTask = null;
+			if (!gatewayResult.IsSuccess)
+				Logger.LogWarning("Gateway issue: {0}", gatewayResult.Error.Message);
 
-				try
-				{
-					client.Disconnected += DisconnectCallback;
-
-					await client.StopAsync().ConfigureAwait(false);
-
-					Logger.LogTrace("Waiting for disconnect callback...");
-					using (cancellationToken.Register(() => disconnectTcs.SetCanceled()))
-						await disconnectTcs.Task.ConfigureAwait(false);
-
-					// https://github.com/discord-net/Discord.Net/blob/8afef8245cfd1f8b56956dd4b4577ed3c6904be5/src/Discord.Net.WebSocket/ConnectionManager.cs#L176
-					// State isn't set to disconnected until AFTER the callback fires
-					// Meaning if we check this.Connected right now it will still return true
-					// Yielding here will prevent this
-					await Task.Yield();
-
-					Logger.LogTrace("Stop async complete.");
-				}
-				finally
-				{
-					client.Disconnected -= DisconnectCallback;
-				}
-
-				cancellationToken.ThrowIfCancellationRequested();
-				var logoutTcs = new TaskCompletionSource<object>();
-				Task LogoutCallback()
-				{
-					logoutTcs.TrySetResult(null);
-					return Task.CompletedTask;
-				}
-
-				client.LoggedOut += LogoutCallback;
-				try
-				{
-					await client.LogoutAsync().ConfigureAwait(false);
-
-					Logger.LogTrace("Waiting for logout callback...");
-					using (cancellationToken.Register(() => logoutTcs.SetCanceled()))
-						await logoutTcs.Task.ConfigureAwait(false);
-				}
-				finally
-				{
-					client.LoggedOut -= LogoutCallback;
-				}
-
-				Logger.LogDebug("Disconnected!");
-			}
-			catch (OperationCanceledException)
-			{
-				throw;
-			}
-			catch (Exception e)
-			{
-				Logger.LogWarning(e, "Error disconnecting from discord!");
-			}
-		}
-
-		/// <summary>
-		/// Handle a message recieved from Discord.
-		/// </summary>
-		/// <param name="e">The <see cref="SocketMessage"/>.</param>
-		/// <returns>A <see cref="Task"/> representing the running operation.</returns>
-		async Task Client_MessageReceived(SocketMessage e)
-		{
-			if (e.Author.Id == client.CurrentUser.Id)
-				return;
-
-			IDisposable typingState = null;
-			void StartTyping() => typingState = e.Channel.EnterTypingState();
-			try
-			{
-				if (basedMeme && e.Content.Equals("Based on what?", StringComparison.OrdinalIgnoreCase))
-				{
-					StartTyping();
-
-					// DCT: None available
-					await SendMessage(
-						e.Channel.Id,
-						"https://youtu.be/LrNu-SuFF_o",
-						default)
-						.ConfigureAwait(false);
-					return;
-				}
-
-				var pm = e.Channel is IPrivateChannel;
-				var shouldNotAnswer = !pm;
-				if (shouldNotAnswer)
-					lock (mappedChannels)
-						shouldNotAnswer = !mappedChannels.Contains(e.Channel.Id);
-
-				var content = NormalizeMentions(e.Content);
-				var mentionedUs = e.MentionedUsers.Any(x => x.Id == client.CurrentUser.Id)
-					|| (!shouldNotAnswer && content.Split(' ').First().Equals(ChatManager.CommonMention, StringComparison.OrdinalIgnoreCase));
-				if (mentionedUs)
-					StartTyping();
-
-				if (shouldNotAnswer)
-				{
-					if (mentionedUs)
-					{
-						Logger.LogTrace("Ignoring mention from {0} ({1}) by {2} ({3}). Channel not mapped!", e.Channel.Id, e.Channel.Name, e.Author.Id, e.Author.Username);
-					}
-
-					return;
-				}
-
-				var result = new Message
-				{
-					Content = content,
-					User = new ChatUser
-					{
-						RealId = e.Author.Id,
-						Channel = new ChannelRepresentation
-						{
-							RealId = e.Channel.Id,
-							IsPrivateChannel = pm,
-							ConnectionName = pm ? e.Author.Username : (e.Channel as ITextChannel)?.Guild.Name ?? "UNKNOWN",
-							FriendlyName = e.Channel.Name,
-
-							// isAdmin and Tag populated by manager
-						},
-						FriendlyName = e.Author.Username,
-						Mention = NormalizeMentions(e.Author.Mention),
-					},
-					Context = typingState,
-				};
-
-				EnqueueMessage(result);
-				typingState = null;
-			}
-			finally
-			{
-				typingState?.Dispose();
-			}
+			gatewayCts.Dispose();
+			gatewayCts = null;
 		}
 	}
 }

src/Tgstation.Server.Host/Components/Chat/Providers/IDiscordResponders.cs

@@ -0,0 +1,12 @@
+using Remora.Discord.API.Abstractions.Gateway.Events;
+using Remora.Discord.Gateway.Responders;
+
+namespace Tgstation.Server.Host.Components.Chat.Providers
+{
+	/// <summary>
+	/// Combined interface for the <see cref="IResponder"/> types used by TGS.
+	/// </summary>
+	interface IDiscordResponders : IResponder<IMessageCreate>
+	{
+	}
+}

src/Tgstation.Server.Host/IO/DefaultIOManager.cs

@@ -369,18 +369,12 @@ namespace Tgstation.Server.Host.IO
 					await CreateDirectory(dest, cancellationToken).ConfigureAwait(false); // save on createdir calls
 
 				var tasks = new List<Task>();
-
-				await dir.EnumerateFiles()
-					.ToAsyncEnumerable()
-					.ForEachAsync(
-					fileInfo =>
-					{
-						if (ignore != null && ignore.Contains(fileInfo.Name))
-							return;
-						tasks.Add(CopyFile(fileInfo.FullName, Path.Combine(dest, fileInfo.Name), cancellationToken));
-					},
-					cancellationToken)
-					.ConfigureAwait(false);
+				foreach (var fileInfo in dir.EnumerateFiles())
+				{
+					if (ignore != null && ignore.Contains(fileInfo.Name))
+						return;
+					tasks.Add(CopyFile(fileInfo.FullName, Path.Combine(dest, fileInfo.Name), cancellationToken));
+				}
 
 				await Task.WhenAll(tasks).ConfigureAwait(false);
 			}

src/Tgstation.Server.Host/Tgstation.Server.Host.csproj

@@ -66,7 +66,6 @@
     <PackageReference Include="Byond.TopicSender" Version="5.0.0" />
     <PackageReference Include="Cyberboss.AspNetCore.AsyncInitializer" Version="1.2.0" />
     <PackageReference Include="Cyberboss.SmartIrc4net.Standard" Version="0.4.6" />
-    <PackageReference Include="Discord.Net.WebSocket" Version="2.4.0" />
     <PackageReference Include="Elastic.CommonSchema.Serilog" Version="1.5.3" />
     <PackageReference Include="GitLabApiClient" Version="1.8.0" />
     <PackageReference Include="LibGit2Sharp" Version="0.27.0-preview-0034" />
@@ -88,6 +87,7 @@
     <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="3.1.11" />
     <PackageReference Include="Octokit" Version="0.50.0" />
     <PackageReference Include="Pomelo.EntityFrameworkCore.MySql" Version="3.2.6" />
+    <PackageReference Include="Remora.Discord" Version="3.0.54" />
     <PackageReference Include="Serilog.Extensions.Logging" Version="3.0.1" />
     <PackageReference Include="Serilog.Sinks.Async" Version="1.5.0" />
     <PackageReference Include="Serilog.Sinks.Console" Version="4.0.0" />