(Add the actual service file, shh)

PluralKit.Bot/Services/ErrorMessageService.cs

@@ -0,0 +1,35 @@
+using System.Collections.Concurrent;
+using System.Threading.Tasks;
+
+using DSharpPlus.Entities;
+
+using NodaTime;
+
+namespace PluralKit.Bot
+{
+    public class ErrorMessageService
+    {
+        private static readonly Duration MinErrorInterval = Duration.FromSeconds(10);
+        private readonly ConcurrentDictionary<ulong, Instant> _lastErrorInChannel = new ConcurrentDictionary<ulong, Instant>();
+
+        public async Task SendErrorMessage(DiscordChannel channel, string errorId)
+        {
+            var now = SystemClock.Instance.GetCurrentInstant(); 
+            if (_lastErrorInChannel.TryGetValue(channel.Id, out var lastErrorTime))
+            {
+                var interval = now - lastErrorTime;
+                if (interval < MinErrorInterval)
+                    return;
+            }
+            _lastErrorInChannel[channel.Id] = now;
+            
+            var embed = new DiscordEmbedBuilder()
+                .WithColor(new DiscordColor(0xE74C3C))
+                .WithTitle("Internal error occurred")
+                .WithDescription("For support, please send the error code above in **#bug-reports-and-errors** on **[the support server *(click to join)*](https://discord.gg/PczBt78)** with a description of what you were doing at the time.")
+                .WithFooter(errorId)
+                .WithTimestamp(now.ToDateTimeOffset());
+            await channel.SendMessageAsync($"> **Error code:** `{errorId}`", embed: embed.Build());
+        }
+    }
+}