Feature/silent message slash command

source/POI.DiscordDotNet/Commands/SlashCommands/Modules/UtilSlashCommandsModule.cs

@@ -1,4 +1,5 @@
 using DSharpPlus.SlashCommands;
+using DSharpPlus.SlashCommands.Attributes;
 using JetBrains.Annotations;
 using Microsoft.Extensions.DependencyInjection;
 using POI.DiscordDotNet.Commands.SlashCommands.Utils;
@@ -20,5 +21,12 @@ await ctx
 		[SlashCommand("uppy", "Shows how long I've been online already 😅"), UsedImplicitly]
 		public Task HandleUptimeCommand(InteractionContext ctx)
 			=> ctx.Services.GetRequiredService<UptimeCommand>().Handle(ctx);
+
+		[SlashCommand("silentmessage", "Send a message anonymously into this channel."), UsedImplicitly]
+		[SlashCooldown(1, 60 * 5, SlashCooldownBucketType.Channel)] // TODO: extract to db + migrations
+		public Task HandleSilentMessageCommand(InteractionContext ctx,
+			[Option("Type", "What type of message do you want to send into this channel?")]
+			AnonymousMessages messageType = AnonymousMessages.StayOnTopicReminder)
+			=> ctx.Services.GetRequiredService<SilentMessageSlashCommands>().Handle(ctx, messageType);
 	}
 }

source/POI.DiscordDotNet/Commands/SlashCommands/Utils/ServiceCollectionExtensions.cs

@@ -5,5 +5,5 @@ namespace POI.DiscordDotNet.Commands.SlashCommands.Utils;
 public static class ServiceCollectionExtensions
 {
 	public static IServiceCollection AddUtilitySlashCommands(this IServiceCollection services) => services
-		.AddTransient<UptimeCommand>();
+		.AddTransient<UptimeCommand>().AddTransient<SilentMessageSlashCommands>();
 }

source/POI.DiscordDotNet/Commands/SlashCommands/Utils/SilentMessageSlashCommands.cs

@@ -0,0 +1,24 @@
+using DSharpPlus.SlashCommands;
+using POI.DiscordDotNet.Commands.SlashCommands.Modules;
+
+namespace POI.DiscordDotNet.Commands.SlashCommands.Utils;
+
+public enum AnonymousMessages
+{
+	[ChoiceName("Stay on Topic reminder")] StayOnTopicReminder
+}
+
+public class SilentMessageSlashCommands: UtilSlashCommandsModule
+{
+	private readonly Dictionary<AnonymousMessages, string> _anonymousMessages = new()
+	{
+		{ AnonymousMessages.StayOnTopicReminder, "\u26a0\ufe0f Beep boop, please stay on topic! \ud83d\ude4f" }
+	};
+
+	public async Task Handle(InteractionContext ctx,
+		AnonymousMessages messageType = AnonymousMessages.StayOnTopicReminder)
+	{
+		await ctx.CreateResponseAsync("Message has been sent.", true).ConfigureAwait(false);
+		await ctx.Channel.SendMessageAsync(_anonymousMessages[messageType]).ConfigureAwait(false);
+	}
+}

source/POI.DiscordDotNet/Services/Implementations/DiscordSlashCommandsService.cs

@@ -1,4 +1,5 @@
 using DSharpPlus.SlashCommands;
+using DSharpPlus.SlashCommands.Attributes;
 using DSharpPlus.SlashCommands.EventArgs;
 using Microsoft.Extensions.Logging;
 using POI.DiscordDotNet.Commands.SlashCommands.Modules;
@@ -51,13 +52,29 @@ public void Cleanup(IDiscordClientProvider discordClientProvider)
 		_slashCommands = null;
 	}
 
-	private Task OnSlashCommandErrored(SlashCommandsExtension _, SlashCommandErrorEventArgs eventArgs)
+	private async Task OnSlashCommandErrored(SlashCommandsExtension _, SlashCommandErrorEventArgs eventArgs)
 	{
+		if (eventArgs.Exception is SlashExecutionChecksFailedException castedException)
+		{
+			var timeLeft = string.Empty;
+			foreach (var error in castedException.FailedChecks)
+			{
+				var cooldown = (SlashCooldownAttribute) error;
+				var rawTime = cooldown.GetRemainingCooldown(eventArgs.Context);
+
+				if (rawTime.Days != 0) timeLeft += $"{rawTime.Days} days, ";
+				if (rawTime.Hours != 0) timeLeft += $"{rawTime.Hours} hours, ";
+				if (rawTime.Minutes != 0) timeLeft += $"{rawTime.Minutes} minutes, ";
+				if (rawTime.Seconds != 0) timeLeft += $"{rawTime.Seconds} seconds";
+			}
+
+			await eventArgs.Context.CreateResponseAsync($"To use that command you need to wait {timeLeft}", true).ConfigureAwait(false);
+			return;
+		}
+
 		_logger.LogError(eventArgs.Exception,
 			"{Username} tried to execute slashcommand /{CommandName}, but it errored",
 			eventArgs.Context.User.Username, eventArgs.Context.CommandName);
-
-		return Task.CompletedTask;
 	}
 
 	private Task OnSlashCommandsExecuted(SlashCommandsExtension _, SlashCommandExecutedEventArgs eventArgs)