fix(reorder): trap layer-list drag drop as a data change and persist it

List_PreviewMouseMove reorders StagedScene.Elements via RemoveAt/Insert, bypassing SceneGraph's mutation surface, but never scheduled a save — the new z-order was lost on restart. The drop now sets _dragReordered and EndListDrag funnels it through MainViewModel.OnSceneElementsReordered() (InvalidateBake + ScheduleSave, same background-save path as every other mutation). Integration test (RealApp + temp DB) reproduces the exact code-behind mutation and asserts the debounced save lands the new Source SortOrder. Derivation reference: standard WPF ItemsControl drag-reorder pattern (OBS layering semantics: bottom-most layer = index 0).
2026-09-18 08:18:51 -07:00
parent fd5198df9f
commit c11788574e
4 changed files with 197 additions and 10 deletions
@@ -0,0 +1,158 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Windows.Threading;
+using Microsoft.Data.Sqlite;
+using Xunit;
+using ytLive.Models;
+using ytLive.Services;
+using ytLive.ViewModels;
+
+namespace ytLive.Tests;
+
+/// <summary>
+/// Layer-list drag-to-reorder: the code-behind reorders StagedScene.Elements
+/// directly (RemoveAt/Insert), bypassing SceneGraph's mutation surface, so the
+/// drop must be trapped as a data change and persisted. Real-App + temp-DB
+/// pattern (see WebcamOutputKeyTests); reuses the exact code-behind mutation and
+/// asserts the new order is written to the DB after the debounced background save.
+/// </summary>
+[Collection("RealApp")]
+public sealed class LayerReorderPersistenceTests
+{
+    private readonly RealAppHost _app;
+
+    public LayerReorderPersistenceTests(RealAppHost app) => _app = app;
+
+    [Fact]
+    public void DragReorder_SurvivesTheDebouncedBackgroundSave()
+    {
+        _app.Run(Run);
+    }
+
+    private void Run()
+    {
+        var tempDb = Path.Combine(Path.GetTempPath(), $"ytLlive-reorder-{Guid.NewGuid():N}.db");
+        MainViewModel.LayoutPathOverride = tempDb;
+        var window = default(MainWindow);
+        try
+        {
+            using (var schema = new LayoutStore(tempDb)) { }
+            SqliteConnection.ClearAllPools();
+            SeedThreeLayers(tempDb);
+
+            window = new MainWindow();
+            var vm = (MainViewModel)window.DataContext;
+            vm.StagedScene = vm.Scenes.Single(s => SceneCatalog.Is(s.Name, SceneCatalog.Live));
+            Assert.True(vm.StagedScene!.Elements.OfType<Source>().Count() >= 4,
+                "3 seeded layers + the healed Background must load");
+
+            // Mirrors Controls/LeftPanel.List_PreviewMouseMove: drag the last layer
+            // to the front of the user layers (the healed Background stays pinned
+            // at index 0, so index 1 is the first user layer).
+            var elements = vm.StagedScene.Elements;
+            var dragged = elements[^1];
+            elements.RemoveAt(elements.Count - 1);
+            elements.Insert(1, dragged);
+            var expected = vm.StagedScene.Elements.OfType<Source>().Select(s => s.Name).ToArray();
+
+            vm.OnSceneElementsReordered();
+
+            Assert.True(PumpUntil(() => SourceNamesInDb(tempDb).SequenceEqual(expected),
+                    TimeSpan.FromSeconds(10)),
+                "the drag reorder must be persisted by the debounced background save");
+            Assert.Equal(expected, SourceNamesInDb(tempDb));
+        }
+        finally
+        {
+            if (window != null) window.Close();
+            MainViewModel.LayoutPathOverride = null;
+            SqliteConnection.ClearAllPools();
+            try { File.Delete(tempDb); } catch { /* best-effort cleanup */ }
+        }
+    }
+
+    /// <summary>Pumps the app dispatcher (so the VM's debounce timer fires) until
+    /// <paramref name="isDone"/> or the deadline passes. True when the condition
+    /// became true, false on deadline.</summary>
+    private static bool PumpUntil(Func<bool> isDone, TimeSpan timeout)
+    {
+        var frame = new DispatcherFrame();
+        var poll = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(100) };
+        var deadline = DateTime.UtcNow + timeout;
+        poll.Tick += (_, _) =>
+        {
+            if (isDone() || DateTime.UtcNow >= deadline)
+            {
+                poll.Stop();
+                frame.Continue = false;
+            }
+        };
+        poll.Start();
+        Dispatcher.PushFrame(frame);
+        return isDone();
+    }
+
+    private static string[] SourceNamesInDb(string path)
+    {
+        try
+        {
+            using var connection = new SqliteConnection($"Data Source={path}");
+            connection.Open();
+            using var cmd = connection.CreateCommand();
+            cmd.CommandText = "SELECT Name FROM Source WHERE SceneId = 'scene-live' ORDER BY SortOrder;";
+            using var reader = cmd.ExecuteReader();
+            var names = new List<string>();
+            while (reader.Read()) names.Add(reader.GetString(0));
+            return names.ToArray();
+        }
+        catch (SqliteException)
+        {
+            // The debounced save may hold the write lock mid-transaction — not yet.
+            return [];
+        }
+    }
+
+    private static void SeedThreeLayers(string path)
+    {
+        using var connection = new SqliteConnection($"Data Source={path}");
+        connection.Open();
+
+        var scenes = new (string Id, string Name)[]
+        {
+            ("scene-starting", "Starting"),
+            ("scene-live", "Live"),
+            ("scene-brb", "BRB"),
+            ("scene-chat", "Chat"),
+            ("scene-ending", "Ending"),
+        };
+        foreach (var (id, name) in scenes)
+        {
+            using var cmd = connection.CreateCommand();
+            cmd.CommandText = "INSERT INTO Scene (Id, Name, HasBackground, SortOrder) VALUES ($id, $name, 1, $order);";
+            cmd.Parameters.AddWithValue("$id", id);
+            cmd.Parameters.AddWithValue("$name", name);
+            cmd.Parameters.AddWithValue("$order", Array.IndexOf(scenes, (id, name)));
+            cmd.ExecuteNonQuery();
+        }
+
+        var layers = new[] { "ImgA", "ImgB", "ImgC" };
+        using (var source = connection.CreateCommand())
+        {
+            source.CommandText =
+                @"INSERT INTO Source (Id, SceneId, Type, Name, IsEnabled, X, Y, Width, Height, IsBackground, SortOrder)
+                  VALUES ($id, 'scene-live', 'Image', $name, 1, 0, 0, 640, 480, 0, $sort);";
+            var idP = source.Parameters.Add("$id", SqliteType.Text);
+            var nameP = source.Parameters.Add("$name", SqliteType.Text);
+            var sortP = source.Parameters.Add("$sort", SqliteType.Integer);
+            for (var i = 0; i < layers.Length; i++)
+            {
+                idP.Value = $"img-{i}";
+                nameP.Value = layers[i];
+                sortP.Value = i;
+                source.ExecuteNonQuery();
+            }
+        }
+    }
+}