fix: reuse scenes for on-air refresh

src/MBN_STOCK_WEBVIEW.Playout/Interop/DynamicK3dSession.cs

@@ -413,9 +413,16 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
 
         try
         {
-            nextScene = new SceneReference(
+            // MainForm refreshes the selected DTO immediately before TAKE IN and
-                InvokeRequired(engine, "LoadScene", cue.SceneFile, cue.SceneName),
+            // Page NEXT can target the alias already on air. Tornado2 rejects a
-                cue.SceneName);
+            // second LoadScene for an alias it still owns, so mutate and re-Prepare
+            // the retained loaded scene instead of creating a duplicate alias.
+            nextScene =
+                ReusableScene(_preparedScene, cue.SceneName) ??
+                ReusableScene(_currentScene, cue.SceneName) ??
+                new SceneReference(
+                    InvokeRequired(engine, "LoadScene", cue.SceneFile, cue.SceneName),
+                    cue.SceneName);
             if (outputChannel.HasValue)
             {
                 Invoke(nextScene.Value, "SetOutputChannelIndex", outputChannel.GetValueOrDefault());
@@ -548,10 +555,16 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
 
         try
         {
-            // MainForm.timer1_Tick replays the current layout before entering
-            // Show_PlayList(idx: 1), then prepares and plays the mutated scene again.
-            InvokeTrackedPlay(layoutIndex);
             playingScene = InvokeRequired(player, "GetPlayingScene", layoutIndex);
+
+            foreach (var mutation in cue.Mutations ?? [])
+            {
+                if (IsBeforeTransactionSceneSetupMutation(mutation))
+                {
+                    ApplySceneSetupMutation(playingScene, mutation);
+                }
+            }
+
             Invoke(engine, "BeginTransaction");
             transactionStarted = true;
 
@@ -562,11 +575,12 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
 
             foreach (var mutation in cue.Mutations ?? [])
             {
-                // The legacy idx == 1 path updates the playing scene in place. It does not
+                // Match Show_PlayList(idx: 1): common background setup runs before the
-                // reapply scene-level background setup or the scene transition effect.
+                // transaction, while builder-owned setup and object changes keep their
-                if (!IsSceneLevelMutation(mutation))
+                // explicit in-transaction ordering.
+                if (!IsBeforeTransactionSceneSetupMutation(mutation))
                 {
-                    ApplyMutation(playingScene, mutation);
+                    ApplyTransactionMutation(playingScene, mutation);
                 }
             }
 
@@ -1080,6 +1094,14 @@ internal sealed class DynamicK3dSession : IK3dGuardedConnectSession
         }
     }
 
+    private static SceneReference? ReusableScene(
+        SceneReference? scene,
+        string sceneName) =>
+        scene is not null &&
+        string.Equals(scene.Name, sceneName, StringComparison.OrdinalIgnoreCase)
+            ? scene
+            : null;
+
     private void MoveAllScenesToPendingTakeOut()
     {
         AddDistinctScene(_pendingTakeOutScenes, _preparedScene);

tests/MBN_STOCK_WEBVIEW.Playout.Tests/DynamicK3dSessionTests.cs

@@ -458,7 +458,7 @@ public sealed class DynamicK3dSessionTests
     }
 
     [Fact]
-    public async Task UpdateOnAir_UsesPlayingSceneWithoutReloadingOrReapplyingSceneSetup()
+    public async Task UpdateOnAir_UsesPlayingSceneAndAppliesOnlyBeforeTransactionBackgroundSetup()
     {
         using var scenes = TemporarySceneDirectory.Create(
             "test-scene.t2s",
@@ -475,6 +475,11 @@ public sealed class DynamicK3dSessionTests
                 new PlayoutUseBackground(false),
                 new PlayoutSetBackgroundTexture("Video/background.vrv"),
                 new PlayoutSetBackgroundVideo("Video/background.vrv", 4, true),
+                new PlayoutSetBackgroundVideo(
+                    "Video/background.vrv",
+                    8,
+                    true,
+                    PlayoutMutationTiming.InTransaction),
                 new PlayoutSetVisible("badge", false)
             ]));
         var log = new FakeComLog();
@@ -509,12 +514,15 @@ public sealed class DynamicK3dSessionTests
         Assert.Equal(
             new[]
             {
-                "Play:10",
                 "GetPlayingScene:10",
+                "UseBackground:0",
+                "SetBackgroundTexture:background.vrv",
+                "SetBackgroundVideo:background.vrv:4:1",
                 "BeginTransaction",
                 "GetObject:headline",
                 "SetValue:headline:page two",
                 "SetVisible:headline:1",
+                "SetBackgroundVideo:background.vrv:8:1",
                 "GetObject:badge",
                 "SetVisible:badge:0",
                 "QueryVariables",
@@ -525,10 +533,7 @@ public sealed class DynamicK3dSessionTests
             updateCalls);
         Assert.DoesNotContain(updateCalls, call =>
             call.StartsWith("LoadScene:", StringComparison.Ordinal) ||
-            call.StartsWith("SetSceneEffectType:", StringComparison.Ordinal) ||
+            call.StartsWith("SetSceneEffectType:", StringComparison.Ordinal));
-            call.StartsWith("UseBackground:", StringComparison.Ordinal) ||
-            call.StartsWith("SetBackgroundTexture:", StringComparison.Ordinal) ||
-            call.StartsWith("SetBackgroundVideo:", StringComparison.Ordinal));
     }
 
     [Fact]
@@ -577,10 +582,6 @@ public sealed class DynamicK3dSessionTests
                 session.ProcessPendingCallbacks(options.LayoutIndex);
                 Assert.True(session.HasPendingLifecycleCallbacks);
 
-                callbacks.Fire("OnScenePlayed", 1, 9, 10);
-                session.ProcessPendingCallbacks(options.LayoutIndex);
-                Assert.True(session.HasPendingLifecycleCallbacks);
-
                 callbacks.Fire("OnScenePlayed", 1, 9, 10);
                 session.ProcessPendingCallbacks(options.LayoutIndex);
                 Assert.False(session.HasPendingLifecycleCallbacks);
@@ -590,11 +591,48 @@ public sealed class DynamicK3dSessionTests
             TimeSpan.FromSeconds(5),
             CancellationToken.None);
 
-        Assert.Equal(3, log.Names.Count(name => name == "Play:10"));
+        Assert.Equal(2, log.Names.Count(name => name == "Play:10"));
         Assert.Equal(1, log.Names.Count(name => name == "GetPlayingScene:10"));
         Assert.DoesNotContain("Unload:5001", log.Names);
     }
 
+    [Fact]
+    public async Task Prepare_SamePreparedScene_ReusesSceneWithoutSecondLoad()
+    {
+        using var scenes = TemporarySceneDirectory.Create("5001.t2s");
+        var options = SceneOptions(scenes.Path, "5001");
+        var log = new FakeComLog();
+        var player = new FakePlayer(log);
+        var scene = new FakeScene(log, "5001");
+        var engine = new FakeEngine(log, player, scene);
+        var activator = new FakeActivator(log, engine);
+        var releaser = new FakeReleaser(
+            log,
+            (scene, "5001"),
+            (player, "Player"),
+            (engine, "Engine"),
+            (activator.EventHandler, "EventHandler"));
+        await using var dispatcher = new StaDispatcher(capacity: 2);
+
+        await dispatcher.InvokeAsync(
+            () =>
+            {
+                using var session = new DynamicK3dSession(activator, releaser);
+                session.Connect(options);
+                session.Prepare(SceneCue(options, "5001"), options.LayoutIndex);
+                session.Prepare(SceneCue(options, "5001"), options.LayoutIndex);
+                session.Disconnect();
+                return true;
+            },
+            TimeSpan.FromSeconds(5),
+            CancellationToken.None);
+
+        Assert.Equal(1, log.Names.Count(name => name == "LoadScene:5001"));
+        Assert.Equal(2, log.Names.Count(name => name == "Prepare:10"));
+        Assert.DoesNotContain("Unload:5001", log.Names);
+        Assert.Equal(1, log.Names.Count(name => name == "Release:5001"));
+    }
+
     [Fact]
     public async Task LifecycleCallbacks_UnloadOnlyRetiredScenesAfterMatchingSuccess()
     {
@@ -682,25 +720,19 @@ public sealed class DynamicK3dSessionTests
     }
 
     [Fact]
-    public async Task LifecycleCallbacks_SameNameReplacement_UnloadsOnlyAfterStopAll()
+    public async Task LifecycleCallbacks_CurrentSameNamePrepare_ReusesActiveSceneUntilStopAll()
     {
         using var scenes = TemporarySceneDirectory.Create("5001.t2s");
         var options = SceneOptions(scenes.Path, "5001");
         var log = new FakeComLog();
         var player = new FakePlayer(log);
-        var retiredScene = new FakeScene(log, "5001");
         var activeScene = new FakeScene(log, "5001");
-        var scenesToLoad = new Queue<FakeScene>([retiredScene, activeScene]);
+        var engine = new FakeEngine(log, player, activeScene);
-        var engine = new FakeEngine(log, player, retiredScene)
-        {
-            SceneResolver = _ => scenesToLoad.Dequeue()
-        };
         var activator = new FakeActivator(log, engine);
         var callbacks = new RecordingEventHandlerFactory();
         var releaser = new FakeReleaser(
             log,
-            (retiredScene, "5001-retired"),
+            (activeScene, "5001"),
-            (activeScene, "5001-active"),
             (player, "Player"),
             (engine, "Engine"),
             (callbacks.Handler, "EventHandler"));
@@ -730,8 +762,8 @@ public sealed class DynamicK3dSessionTests
                     0,
                     session.ProcessPendingCallbacks(options.LayoutIndex).UnloadedSceneCount);
                 Assert.DoesNotContain("Unload:5001", log.Names);
-                Assert.Contains("Release:5001-retired", log.Names);
+                Assert.DoesNotContain("Release:5001", log.Names);
-                Assert.DoesNotContain("Release:5001-active", log.Names);
+                Assert.Equal(1, log.Names.Count(name => name == "LoadScene:5001"));
 
                 session.TakeOut(options.LayoutIndex, PlayoutTakeOutScope.All);
                 callbacks.Fire("OnStopAll", 1);
@@ -739,39 +771,32 @@ public sealed class DynamicK3dSessionTests
                     1,
                     session.ProcessPendingCallbacks(options.LayoutIndex).UnloadedSceneCount);
                 Assert.Equal(1, log.Names.Count(name => name == "Unload:5001"));
-                Assert.Contains("Release:5001-active", log.Names);
+                Assert.Contains("Release:5001", log.Names);
                 session.Disconnect();
                 return true;
             },
             TimeSpan.FromSeconds(5),
             CancellationToken.None);
 
-        Assert.Empty(scenesToLoad);
+        Assert.Equal(1, log.Names.Count(name => name == "LoadScene:5001"));
         Assert.Equal(1, log.Names.Count(name => name == "Unload:5001"));
-        Assert.Equal(1, log.Names.Count(name => name == "Release:5001-retired"));
+        Assert.Equal(1, log.Names.Count(name => name == "Release:5001"));
-        Assert.Equal(1, log.Names.Count(name => name == "Release:5001-active"));
     }
 
     [Fact]
-    public async Task LifecycleCallbacks_SameNameReplacement_IgnoresSceneNameCasing()
+    public async Task Prepare_CurrentSceneReuse_IgnoresSceneNameCasing()
     {
         using var scenes = TemporarySceneDirectory.Create("SceneA.t2s");
         var options = SceneOptions(scenes.Path, "SceneA");
         var log = new FakeComLog();
         var player = new FakePlayer(log);
-        var retiredScene = new FakeScene(log, "SceneA");
+        var activeScene = new FakeScene(log, "SceneA");
-        var activeScene = new FakeScene(log, "scenea");
+        var engine = new FakeEngine(log, player, activeScene);
-        var scenesToLoad = new Queue<FakeScene>([retiredScene, activeScene]);
-        var engine = new FakeEngine(log, player, retiredScene)
-        {
-            SceneResolver = _ => scenesToLoad.Dequeue()
-        };
         var activator = new FakeActivator(log, engine);
         var callbacks = new RecordingEventHandlerFactory();
         var releaser = new FakeReleaser(
             log,
-            (retiredScene, "SceneA-retired"),
+            (activeScene, "SceneA"),
-            (activeScene, "scenea-active"),
             (player, "Player"),
             (engine, "Engine"),
             (callbacks.Handler, "EventHandler"));
@@ -799,7 +824,9 @@ public sealed class DynamicK3dSessionTests
                     0,
                     session.ProcessPendingCallbacks(options.LayoutIndex).UnloadedSceneCount);
                 Assert.DoesNotContain("Unload:SceneA", log.Names);
-                Assert.Contains("Release:SceneA-retired", log.Names);
+                Assert.DoesNotContain("Release:SceneA", log.Names);
+                Assert.Equal(1, log.Names.Count(name => name == "LoadScene:SceneA"));
+                Assert.DoesNotContain("LoadScene:scenea", log.Names);
 
                 session.TakeOut(options.LayoutIndex, PlayoutTakeOutScope.All);
                 callbacks.Fire("OnStopAll", 1);
@@ -812,11 +839,10 @@ public sealed class DynamicK3dSessionTests
             TimeSpan.FromSeconds(5),
             CancellationToken.None);
 
-        Assert.Empty(scenesToLoad);
+        Assert.Equal(1, log.Names.Count(name => name == "LoadScene:SceneA"));
-        Assert.DoesNotContain("Unload:SceneA", log.Names);
+        Assert.DoesNotContain("LoadScene:scenea", log.Names);
-        Assert.Equal(1, log.Names.Count(name => name == "Unload:scenea"));
+        Assert.Equal(1, log.Names.Count(name => name == "Unload:SceneA"));
-        Assert.Equal(1, log.Names.Count(name => name == "Release:SceneA-retired"));
+        Assert.Equal(1, log.Names.Count(name => name == "Release:SceneA"));
-        Assert.Equal(1, log.Names.Count(name => name == "Release:scenea-active"));
     }
 
     [Fact]