feat: decrement message counts when messages deleted

PluralKit.Bot/Handlers/MessageDeleted.cs

@@ -32,6 +32,16 @@ public class MessageDeleted: IEventHandler<MessageDeleteEvent>, IEventHandler<Me
         async Task Inner()
         {
             await Task.Delay(MessageDeleteDelay);
+
+            var message = await _repo.GetMessage(evt.Id);
+            if (message == null) return;
+
+            if (message.Member.HasValue)
+            {
+                var memberFull = await _repo.GetMember(message.Member.Value);
+                await _repo.UpdateMemberForDeletedMessage(message.Member.Value, memberFull.MessageCount);
+            }
+
             await _repo.DeleteMessage(evt.Id);
         }
 

PluralKit.Bot/Handlers/ReactionAdded.cs

@@ -141,8 +141,6 @@ public class ReactionAdded: IEventHandler<MessageReactionAddEvent>
         {
             // Message was deleted by something/someone else before we got to it
         }
-
-        await _repo.DeleteMessage(evt.MessageId);
     }
 
     private async ValueTask HandleCommandDeleteReaction(MessageReactionAddEvent evt, ulong? authorId, bool isDM)

PluralKit.Core/Database/Repository/ModelRepository.Member.cs

@@ -110,4 +110,27 @@ public partial class ModelRepository
 
         await _db.ExecuteQuery(query);
     }
+
+    public async Task UpdateMemberForDeletedMessage(MemberId id, int msgCount)
+    {
+        if (msgCount <= 0) return;
+
+        var query = new Query("members")
+            .When(msgCount > 1,
+                // when there are plenty of messages
+                q => q.AsUpdate(new
+                {
+                    message_count = new UnsafeLiteral("message_count - 1")
+                }),
+                // when this is the only message (if the db for some reason thinks there are no messages we already returned)
+                q => q.AsUpdate(new
+                {
+                    message_count = new UnsafeLiteral("message_count - 1"),
+                    last_message_timestamp = new UnsafeLiteral("null")
+                })
+            )
+            .Where("id", id);
+
+        await _db.ExecuteQuery(query);
+    }
 }