Add handling command ❌ reactions

and, uhh, rename invoker_id to author_id

PluralKit.Bot/Handlers/ReactionAdded.cs

@@ -48,12 +48,15 @@ namespace PluralKit.Bot
                 _db.Execute(c => _repo.GetMessage(c, evt.Message.Id));
 
             FullMessage msg;
+            CommandMessage cmdmsg;
             switch (evt.Emoji.Name)
             {
                 // Message deletion
                 case "\u274C": // Red X
                     if ((msg = await GetMessage()) != null)
                         await HandleDeleteReaction(evt, msg);
+                    else if ((cmdmsg = await _db.Execute(conn => _repo.GetCommandMessage(conn, evt.Message.Id))) != null)
+                        await HandleCommandDeleteReaction(evt, cmdmsg);
                     break;                
                 
                 case "\u2753": // Red question mark
@@ -92,6 +95,25 @@ namespace PluralKit.Bot
             await _db.Execute(c => _repo.DeleteMessage(c, evt.Message.Id));
         }
 
+        private async ValueTask HandleCommandDeleteReaction(MessageReactionAddEventArgs evt, CommandMessage msg)
+        {
+            if (!evt.Channel.BotHasAllPermissions(Permissions.ManageMessages)) return;
+
+            // Can only delete your own message
+            if (msg.author_id != evt.User.Id) return;
+
+            try
+            {
+                await evt.Message.DeleteAsync();
+            }
+            catch (NotFoundException)
+            {
+                // Message was deleted by something/someone else before we got to it
+            }
+
+            // No need to delete database row here, it'll get deleted by the once-per-minute scheduled task.
+        }
+
         private async ValueTask HandleQueryReaction(MessageReactionAddEventArgs evt, FullMessage msg)
         {
             // Try to DM the user info about the message

PluralKit.Core/Database/Migrations/11.sql

@@ -4,7 +4,7 @@
 create table command_message
 (
 	message_id bigint primary key,
-	invoker_id bigint not null,
+	author_id bigint not null,
 	timestamp timestamp not null default now()
 );
 

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

@@ -9,7 +9,16 @@ namespace PluralKit.Core
     public partial class ModelRepository
 	{
 		public Task SaveCommandMessage(IPKConnection conn, ulong message_id, ulong author_id) =>
-			conn.QueryAsync("insert into command_message (message_id, invoker_id) values (@Message, @Author)",
+			conn.QueryAsync("insert into command_message (message_id, author_id) values (@Message, @Author)",
 				new {Message = message_id, Author = author_id });
+
+		public Task<CommandMessage> GetCommandMessage(IPKConnection conn, ulong message_id) =>
+			conn.QuerySingleOrDefaultAsync<CommandMessage>("select message_id, author_id from command_message where message_id = @Message", 
+				new {Message = message_id});
+	}
+
+	public class CommandMessage
+	{
+		public ulong author_id { get; set; }
 	}
 }