basically function but needs a lot of refinement

CommandHandler.cs

@@ -1,18 +1,20 @@
 using Godot;
 using System;
 using System.Collections;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Net.Http;
 using System.Text.RegularExpressions;
+using System.Threading;
 using System.Threading.Tasks;
 
 public partial class CommandHandler : Node
 {
 	private Settings Settings { get; set; }
 	private game Game { get; set; }
-	private readonly List<Task> TaskQueue = new();
+	private readonly ConcurrentQueue<Action> ActionQueue = new();
 	private System.Net.Http.HttpClient _Client = null;
 	private System.Net.Http.HttpClient Client
 	{ get
@@ -21,34 +23,42 @@ public partial class CommandHandler : Node
 			return _Client;
 		}
 	}
+	private defer_manager _Deferer = null;
+	private defer_manager Deferer
+	{ get
+		{
+			_Deferer ??= GetNode<defer_manager>("/root/DeferManager");
+			return _Deferer;
+		}
+	}
 	// Called when the node enters the scene tree for the first time.
 	public override void _Ready()
 	{
 		Settings = GetNode<Settings>("/root/Settings");
 		Game = GetNode<game>("/root/Game");
+		GetNode<TwitchChatWatcher>("/root/TwitchChatWatcher").IncomingCommand
+			+= IncomingCommand;
 	}
 
 	// Called every frame. 'delta' is the elapsed time since the previous frame.
 	public override void _Process(double delta)
 	{
-		//delete/cleanup one finished task per frame
-		//currently just logs errors
-		var t = TaskQueue.FirstOrDefault(t => t.IsCompleted, null);
-		if (t is not null)
+		while (ActionQueue.TryDequeue(out Action t))
 		{
-			if (t.Exception is not null)
-				GD.PrintErr(t.Exception);
-			TaskQueue.Remove(t);
+			t?.Invoke();
 		}
 	}
 
 	private void IncomingCommand(Command command)
 	{
+		GD.Print("Received command");
 		if (!Settings.IsUserAuthorized(command.User, command.IsStreamer,
 			command.IsModerator))
 			return;
+		GD.Print($"User {command.User} is authorized");
 		var baseArgs = command.GetArgs();
 		var type = CommandTypeHelper.ParseCommand(baseArgs.Pop());
+		GD.Print($"Command type: {type}");
 		var args = baseArgs.DuplicateAtState();
 		switch (type)
 		{
@@ -65,7 +75,9 @@ public partial class CommandHandler : Node
 				DeleteRow(args);
 				break;
 			case CommandType.CreateCard:
-				TaskQueue.Add(Task.Run(() => CreateCard(args)));
+				Task.Run(async () => await CreateCard(args))
+					.ContinueWith(t => GD.PrintErr(t.Exception.StackTrace),
+					TaskContinuationOptions.OnlyOnFaulted);
 				break;
 			case CommandType.CreateRow:
 				CreateRow(args);
@@ -80,10 +92,12 @@ public partial class CommandHandler : Node
 				RecolorRow(args);
 				break;
 			case CommandType.ChangeCardImage:
-				TaskQueue.Add(Task.Run(() => ChangeCardImage(args)));
+				Task.Run(async () => await ChangeCardImage(args))
+					.ContinueWith(t => GD.PushError(t.Exception.InnerException.StackTrace),
+					TaskContinuationOptions.OnlyOnFaulted);
 				break;
 			default:
-				throw new Exception();
+				throw new Exception("invalid command type");
 		}
 	}
 
@@ -120,10 +134,14 @@ public partial class CommandHandler : Node
 	}
 	private async Task CreateCard(CommandArguments args)
 	{
-		var title = args.Pop();
 		var url = args.Pop();
-		Image img = await ImageFromUrl(url);
-		Game.CreateCard(title, img);
+		var title = args.Remaining();
+		ImageWithMetadata img;
+		if (!string.IsNullOrWhiteSpace(url) && url != "_")
+			img = await ImageFromUrl(url);
+		else
+			img = null;
+		await Deferer.DeferAsync(() => Game.CreateCard(title, img));
 	}
     private void CreateRow(CommandArguments args)
 	{
@@ -152,7 +170,8 @@ public partial class CommandHandler : Node
 		var rowId = args.Pop();
 		var colorStr = args.Pop();
 		var color = Color.FromString(colorStr, new Color(0, 0, 0, 0));
-		if (color == new Color(0, 0, 0, 0))
+		GD.Print($"Recoloring row to {color}");
+		if (color.IsEqualApprox(new Color(0, 0, 0, 0)))
 			throw new Exception($"invalid color {colorStr}");
 		Game.RecolorRow(rowId, color);
 	}
@@ -160,18 +179,38 @@ public partial class CommandHandler : Node
     {
         var cardId = args.Pop();
 		var img = await ImageFromUrl(args.Pop());
-		Game.ChangeCardImage(cardId, img);
+		await Deferer.DeferAsync(() => Game.ChangeCardImage(cardId, img));
+		// Game.ChangeCardImage(cardId, img);
     }
-	private async Task<Image> ImageFromUrl(string url)
+	private async Task<ImageWithMetadata> ImageFromUrl(string url)
 	{
+		StretchMode mode = StretchMode.Unspecified;
+		if (url.Contains('|'))
+		{
+			var spl = url.Split('|', 2);
+			url = spl[0];
+			mode = spl[1].ToLower() switch
+			{
+				"unspecified" => StretchMode.Unspecified,
+				"fit" => StretchMode.Fit,
+				"stretch" => StretchMode.Stretch,
+				"crop" => StretchMode.Crop,
+				_ => throw new Exception($"Unrecognized {nameof(StretchMode)}"),
+			};
+		}
+		GD.Print($"Stretch mode: {mode}");
 		var uri = new Uri(url);
+		GD.Print("Starting image download");
 		var resp = await Client.GetAsync(uri);
 		if (!resp.IsSuccessStatusCode)
-			return null;
+			throw new Exception("Failed to download image");
+		GD.Print("Downloaded image successfully");
 		Image img = new();
 		var arr = await resp.Content.ReadAsByteArrayAsync();
+		var ext = Path.GetExtension(uri.AbsolutePath).TrimStart('.').ToLower();
+		GD.Print($"Image extension: {ext}");
 		//TODO detect images by header rather than extension
-		switch (Path.GetExtension(uri.AbsolutePath).ToLower())
+		switch (ext)
 		{
 			case "png":
 				img.LoadPngFromBuffer(arr);
@@ -189,7 +228,8 @@ public partial class CommandHandler : Node
 			default:
 				throw new Exception("unrecognized filetype");
 		}
-		return img;
+		GD.Print($"Loaded picture {img}");
+		return new ImageWithMetadata(img, mode);
 	}
 	protected override void Dispose(bool disposing)
 	{