LYN-7121 | Focus Mode - Make editing a prefab an undoable operation (#4582)

* Refactor the PrefabFocusInterface to differentiate between Public and Internal functions. Introduce PrefabFocusUndo nodes to allow undoing Prefab Edit operations.

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Fix selection code to avoid warning message

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Removed changed property from PrefabFocusUndo node

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Switch from size == 0 to empty in EntityOutlinerWidget::OnSelectionChanged

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* condense if check on Prefab Edit context menu item setup

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Correct interface usage in PrefabIntegrationManager (interface was renamed to public)

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Remove rej file that was included by mistake

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

* Fix missing interface initialization in PrefabFocusTests

Signed-off-by: Danilo Aimini <82231674+AMZN-daimini@users.noreply.github.com>

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabFocusHandler.cpp

@@ -8,12 +8,14 @@
 
 #include <AzToolsFramework/Prefab/PrefabFocusHandler.h>
 
+#include <AzToolsFramework/Commands/SelectionCommand.h>
 #include <AzToolsFramework/ContainerEntity/ContainerEntityInterface.h>
 #include <AzToolsFramework/Entity/EditorEntityHelpers.h>
 #include <AzToolsFramework/Entity/PrefabEditorEntityOwnershipInterface.h>
 #include <AzToolsFramework/Prefab/Instance/Instance.h>
 #include <AzToolsFramework/Prefab/Instance/InstanceEntityMapperInterface.h>
 #include <AzToolsFramework/Prefab/PrefabFocusNotificationBus.h>
+#include <AzToolsFramework/Prefab/PrefabFocusUndo.h>
 
 namespace AzToolsFramework::Prefab
 {
@@ -28,10 +30,12 @@ namespace AzToolsFramework::Prefab
 
         EditorEntityContextNotificationBus::Handler::BusConnect();
         AZ::Interface<PrefabFocusInterface>::Register(this);
+        AZ::Interface<PrefabFocusPublicInterface>::Register(this);
     }
 
     PrefabFocusHandler::~PrefabFocusHandler()
     {
+        AZ::Interface<PrefabFocusPublicInterface>::Unregister(this);
         AZ::Interface<PrefabFocusInterface>::Unregister(this);
         EditorEntityContextNotificationBus::Handler::BusDisconnect();
     }
@@ -61,6 +65,44 @@ namespace AzToolsFramework::Prefab
     }
 
     PrefabFocusOperationResult PrefabFocusHandler::FocusOnOwningPrefab(AZ::EntityId entityId)
+    {
+        // Initialize Undo Batch object
+        ScopedUndoBatch undoBatch("Edit Prefab");
+
+        // Clear selection
+        {
+            const EntityIdList selectedEntities = EntityIdList{};
+            auto selectionUndo = aznew SelectionCommand(selectedEntities, "Clear Selection");
+            selectionUndo->SetParent(undoBatch.GetUndoBatch());
+            ToolsApplicationRequestBus::Broadcast(&ToolsApplicationRequestBus::Events::SetSelectedEntities, selectedEntities);
+        }
+
+        // Edit Prefab
+        {
+            auto editUndo = aznew PrefabFocusUndo("Edit Prefab");
+            editUndo->Capture(entityId);
+            editUndo->SetParent(undoBatch.GetUndoBatch());
+            ToolsApplicationRequestBus::Broadcast(&ToolsApplicationRequestBus::Events::RunRedoSeparately, editUndo);
+        }
+
+        return AZ::Success();
+    }
+
+    PrefabFocusOperationResult PrefabFocusHandler::FocusOnPathIndex([[maybe_unused]] AzFramework::EntityContextId entityContextId, int index)
+    {
+        if (index < 0 || index >= m_instanceFocusVector.size())
+        {
+            return AZ::Failure(AZStd::string("Prefab Focus Handler: Invalid index on FocusOnPathIndex."));
+        }
+
+        InstanceOptionalReference focusedInstance = m_instanceFocusVector[index];
+
+        FocusOnOwningPrefab(focusedInstance->get().GetContainerEntityId());
+
+        return AZ::Success();
+    }
+
+    PrefabFocusOperationResult PrefabFocusHandler::FocusOnPrefabInstanceOwningEntityId(AZ::EntityId entityId)
     {
         InstanceOptionalReference focusedInstance;
 
@@ -85,18 +127,6 @@ namespace AzToolsFramework::Prefab
         return FocusOnPrefabInstance(focusedInstance);
     }
 
-    PrefabFocusOperationResult PrefabFocusHandler::FocusOnPathIndex([[maybe_unused]] AzFramework::EntityContextId entityContextId, int index)
-    {
-        if (index < 0 || index >= m_instanceFocusVector.size())
-        {
-            return AZ::Failure(AZStd::string("Prefab Focus Handler: Invalid index on FocusOnPathIndex."));
-        }
-
-        InstanceOptionalReference focusedInstance = m_instanceFocusVector[index];
-
-        return FocusOnPrefabInstance(focusedInstance);
-    }
-
     PrefabFocusOperationResult PrefabFocusHandler::FocusOnPrefabInstance(InstanceOptionalReference focusedInstance)
     {
         if (!focusedInstance.has_value())
@@ -122,17 +152,10 @@ namespace AzToolsFramework::Prefab
             if (focusedInstance->get().GetParentInstance() != AZStd::nullopt)
             {
                 containerEntityId = focusedInstance->get().GetContainerEntityId();
-
-                // Select the container entity
-                AzToolsFramework::SelectEntity(containerEntityId);
             }
             else
             {
                 containerEntityId = AZ::EntityId();
-
-                // Clear the selection
-                AzToolsFramework::SelectEntities({});
-                
             }
             
             // Focus on the descendants of the container entity
@@ -161,6 +184,17 @@ namespace AzToolsFramework::Prefab
         return m_focusedInstance;
     }
 
+    AZ::EntityId PrefabFocusHandler::GetFocusedPrefabContainerEntityId([[maybe_unused]] AzFramework::EntityContextId entityContextId) const
+    {
+        if (!m_focusedInstance.has_value())
+        {
+            // PrefabFocusHandler has not been initialized yet.
+            return AZ::EntityId();
+        }
+
+        return m_focusedInstance->get().GetContainerEntityId();
+    }
+
     bool PrefabFocusHandler::IsOwningPrefabBeingFocused(AZ::EntityId entityId) const
     {
         if (!m_focusedInstance.has_value())
@@ -200,7 +234,7 @@ namespace AzToolsFramework::Prefab
         m_instanceFocusVector.clear();
 
         // Focus on the root prefab (AZ::EntityId() will default to it)
-        FocusOnOwningPrefab(AZ::EntityId());
+        FocusOnPrefabInstanceOwningEntityId(AZ::EntityId());
     }
 
     void PrefabFocusHandler::RefreshInstanceFocusList()

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabFocusHandler.h

@@ -13,6 +13,7 @@
 #include <AzToolsFramework/Entity/EditorEntityContextBus.h>
 #include <AzToolsFramework/FocusMode/FocusModeInterface.h>
 #include <AzToolsFramework/Prefab/PrefabFocusInterface.h>
+#include <AzToolsFramework/Prefab/PrefabFocusPublicInterface.h>
 #include <AzToolsFramework/Prefab/Template/Template.h>
 
 namespace AzToolsFramework
@@ -28,6 +29,7 @@ namespace AzToolsFramework::Prefab
     //! Handles Prefab Focus mode, determining which prefab file entity changes will target.
     class PrefabFocusHandler final
         : private PrefabFocusInterface
+        , private PrefabFocusPublicInterface
         , private EditorEntityContextNotificationBus::Handler
     {
     public:
@@ -39,10 +41,14 @@ namespace AzToolsFramework::Prefab
         void Initialize();
 
         // PrefabFocusInterface overrides ...
-        PrefabFocusOperationResult FocusOnOwningPrefab(AZ::EntityId entityId) override;
-        PrefabFocusOperationResult FocusOnPathIndex(AzFramework::EntityContextId entityContextId, int index) override;
+        PrefabFocusOperationResult FocusOnPrefabInstanceOwningEntityId(AZ::EntityId entityId) override;
         TemplateId GetFocusedPrefabTemplateId(AzFramework::EntityContextId entityContextId) const override;
         InstanceOptionalReference GetFocusedPrefabInstance(AzFramework::EntityContextId entityContextId) const override;
+
+        // PrefabFocusPublicInterface overrides ...
+        PrefabFocusOperationResult FocusOnOwningPrefab(AZ::EntityId entityId) override;
+        PrefabFocusOperationResult FocusOnPathIndex(AzFramework::EntityContextId entityContextId, int index) override;
+        AZ::EntityId GetFocusedPrefabContainerEntityId(AzFramework::EntityContextId entityContextId) const override;
         bool IsOwningPrefabBeingFocused(AZ::EntityId entityId) const override;
         const AZ::IO::Path& GetPrefabFocusPath(AzFramework::EntityContextId entityContextId) const override;
         const int GetPrefabFocusPathLength(AzFramework::EntityContextId entityContextId) const override;

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabFocusInterface.h

@@ -20,7 +20,7 @@ namespace AzToolsFramework::Prefab
 {
     using PrefabFocusOperationResult = AZ::Outcome<void, AZStd::string>;
 
-    //! Interface to handle operations related to the Prefab Focus system.
+    //! Interface to handle internal operations related to the Prefab Focus system.
     class PrefabFocusInterface
     {
     public:
@@ -28,29 +28,13 @@ namespace AzToolsFramework::Prefab
 
         //! Set the focused prefab instance to the owning instance of the entityId provided.
         //! @param entityId The entityId of the entity whose owning instance we want the prefab system to focus on.
-        virtual PrefabFocusOperationResult FocusOnOwningPrefab(AZ::EntityId entityId) = 0;
-
-        //! Set the focused prefab instance to the instance at position index of the current path.
-        //! @param index The index of the instance in the current path that we want the prefab system to focus on.
-        virtual PrefabFocusOperationResult FocusOnPathIndex(AzFramework::EntityContextId entityContextId, int index) = 0;
+        virtual PrefabFocusOperationResult FocusOnPrefabInstanceOwningEntityId(AZ::EntityId entityId) = 0;
 
         //! Returns the template id of the instance the prefab system is focusing on.
         virtual TemplateId GetFocusedPrefabTemplateId(AzFramework::EntityContextId entityContextId) const = 0;
 
         //! Returns a reference to the instance the prefab system is focusing on.
         virtual InstanceOptionalReference GetFocusedPrefabInstance(AzFramework::EntityContextId entityContextId) const = 0;
-
-        //! Returns whether the entity belongs to the instance that is being focused on, or one of its descendants.
-        //! @param entityId The entityId of the queried entity.
-        //! @return true if the entity belongs to the focused instance or one of its descendants, false otherwise.
-        virtual bool IsOwningPrefabBeingFocused(AZ::EntityId entityId) const = 0;
-
-        //! Returns the path from the root instance to the currently focused instance.
-        //! @return A path composed from the names of the container entities for the instance path.
-        virtual const AZ::IO::Path& GetPrefabFocusPath(AzFramework::EntityContextId entityContextId) const = 0;
-
-        //! Returns the size of the path to the currently focused instance.
-        virtual const int GetPrefabFocusPathLength(AzFramework::EntityContextId entityContextId) const = 0;
     };
 
 } // namespace AzToolsFramework::Prefab

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabFocusPublicInterface.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#pragma once
+
+#include <AzCore/Interface/Interface.h>
+#include <AzCore/Serialization/SerializeContext.h>
+
+#include <AzFramework/Entity/EntityContext.h>
+
+#include <AzToolsFramework/Prefab/Instance/Instance.h>
+#include <AzToolsFramework/Prefab/Template/Template.h>
+
+namespace AzToolsFramework::Prefab
+{
+    using PrefabFocusOperationResult = AZ::Outcome<void, AZStd::string>;
+
+    //! Public Interface for external systems to utilize the Prefab Focus system.
+    class PrefabFocusPublicInterface
+    {
+    public:
+        AZ_RTTI(PrefabFocusPublicInterface, "{53EE1D18-A41F-4DB1-9B73-9448F425722E}");
+
+        //! Set the focused prefab instance to the owning instance of the entityId provided. Supports undo/redo.
+        //! @param entityId The entityId of the entity whose owning instance we want the prefab system to focus on.
+        virtual PrefabFocusOperationResult FocusOnOwningPrefab(AZ::EntityId entityId) = 0;
+
+        //! Set the focused prefab instance to the instance at position index of the current path. Supports undo/redo.
+        //! @param index The index of the instance in the current path that we want the prefab system to focus on.
+        virtual PrefabFocusOperationResult FocusOnPathIndex(AzFramework::EntityContextId entityContextId, int index) = 0;
+
+        //! Returns the entity id of the container entity for the instance the prefab system is focusing on.
+        virtual AZ::EntityId GetFocusedPrefabContainerEntityId(AzFramework::EntityContextId entityContextId) const = 0;
+
+        //! Returns whether the entity belongs to the instance that is being focused on, or one of its descendants.
+        //! @param entityId The entityId of the queried entity.
+        //! @return true if the entity belongs to the focused instance or one of its descendants, false otherwise.
+        virtual bool IsOwningPrefabBeingFocused(AZ::EntityId entityId) const = 0;
+
+        //! Returns the path from the root instance to the currently focused instance.
+        //! @return A path composed from the names of the container entities for the instance path.
+        virtual const AZ::IO::Path& GetPrefabFocusPath(AzFramework::EntityContextId entityContextId) const = 0;
+
+        //! Returns the size of the path to the currently focused instance.
+        virtual const int GetPrefabFocusPathLength(AzFramework::EntityContextId entityContextId) const = 0;
+    };
+
+} // namespace AzToolsFramework::Prefab

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabFocusUndo.cpp

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#include <AzToolsFramework/Prefab/PrefabFocusUndo.h>
+
+#include <AzCore/Interface/Interface.h>
+#include <AzToolsFramework/Entity/EditorEntityContextBus.h>
+#include <AzToolsFramework/Prefab/PrefabFocusInterface.h>
+#include <AzToolsFramework/Prefab/PrefabFocusPublicInterface.h>
+
+namespace AzToolsFramework::Prefab
+{
+    PrefabFocusUndo::PrefabFocusUndo(const AZStd::string& undoOperationName)
+        : UndoSystem::URSequencePoint(undoOperationName)
+    {
+        m_prefabFocusInterface = AZ::Interface<PrefabFocusInterface>::Get();
+        AZ_Assert(m_prefabFocusInterface, "PrefabFocusUndo - Failed to grab prefab focus interface");
+
+        m_prefabFocusPublicInterface = AZ::Interface<PrefabFocusPublicInterface>::Get();
+        AZ_Assert(m_prefabFocusPublicInterface, "PrefabFocusUndo - Failed to grab prefab focus public interface");
+    }
+
+    bool PrefabFocusUndo::Changed() const
+    {
+        return true;
+    }
+
+    void PrefabFocusUndo::Capture(AZ::EntityId entityId)
+    {
+        auto entityContextId = AzFramework::EntityContextId::CreateNull();
+        EditorEntityContextRequestBus::BroadcastResult(entityContextId, &EditorEntityContextRequests::GetEditorEntityContextId);
+
+        m_beforeEntityId = m_prefabFocusPublicInterface->GetFocusedPrefabContainerEntityId(entityContextId);
+        m_afterEntityId = entityId;
+    }
+
+    void PrefabFocusUndo::Undo()
+    {
+        m_prefabFocusInterface->FocusOnPrefabInstanceOwningEntityId(m_beforeEntityId);
+    }
+
+    void PrefabFocusUndo::Redo()
+    {
+        m_prefabFocusInterface->FocusOnPrefabInstanceOwningEntityId(m_afterEntityId);
+    }
+
+} // namespace AzToolsFramework::Prefab

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/PrefabFocusUndo.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) Contributors to the Open 3D Engine Project.
+ * For complete copyright and license terms please see the LICENSE at the root of this distribution.
+ *
+ * SPDX-License-Identifier: Apache-2.0 OR MIT
+ *
+ */
+
+#pragma once
+
+#include <AzCore/Component/EntityId.h>
+#include <AzToolsFramework/Undo/UndoSystem.h>
+
+namespace AzToolsFramework::Prefab
+{
+    class PrefabFocusInterface;
+    class PrefabFocusPublicInterface;
+
+    //! Undo node for prefab focus change operations.
+    class PrefabFocusUndo
+        : public UndoSystem::URSequencePoint
+    {
+    public:
+        explicit PrefabFocusUndo(const AZStd::string& undoOperationName);
+
+        bool Changed() const override;
+        void Capture(AZ::EntityId entityId);
+
+        void Undo() override;
+        void Redo() override;
+
+    protected:
+        PrefabFocusInterface* m_prefabFocusInterface = nullptr;
+        PrefabFocusPublicInterface* m_prefabFocusPublicInterface = nullptr;
+
+        AZ::EntityId m_beforeEntityId;
+        AZ::EntityId m_afterEntityId;
+    };
+} // namespace AzToolsFramework::Prefab

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Outliner/EntityOutlinerWidget.cpp

@@ -324,7 +324,8 @@ namespace AzToolsFramework
     //  Currently, the first behavior is implemented.
     void EntityOutlinerWidget::OnSelectionChanged(const QItemSelection& selected, const QItemSelection& deselected)
     {
-        if (m_selectionChangeInProgress || !m_enableSelectionUpdates)
+        if (m_selectionChangeInProgress || !m_enableSelectionUpdates
+            || (selected.empty() && deselected.empty()))
         {
             return;
         }

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabIntegrationManager.cpp

@@ -24,11 +24,11 @@
 #include <AzToolsFramework/AssetBrowser/AssetSelectionModel.h>
 #include <AzToolsFramework/AssetBrowser/Entries/SourceAssetBrowserEntry.h>
 #include <AzToolsFramework/ContainerEntity/ContainerEntityInterface.h>
-#include <AzToolsFramework/Prefab/PrefabFocusInterface.h>
+#include <AzToolsFramework/Prefab/EditorPrefabComponent.h>
+#include <AzToolsFramework/Prefab/Instance/InstanceEntityMapperInterface.h>
+#include <AzToolsFramework/Prefab/PrefabFocusPublicInterface.h>
 #include <AzToolsFramework/Prefab/PrefabLoaderInterface.h>
 #include <AzToolsFramework/Prefab/Procedural/ProceduralPrefabAsset.h>
-#include <AzToolsFramework/Prefab/Instance/InstanceEntityMapperInterface.h>
-#include <AzToolsFramework/Prefab/EditorPrefabComponent.h>
 #include <AzToolsFramework/ToolsComponents/EditorLayerComponentBus.h>
 #include <AzToolsFramework/UI/EditorEntityUi/EditorEntityUiInterface.h>
 #include <AzToolsFramework/UI/Prefab/PrefabIntegrationInterface.h>
@@ -39,7 +39,6 @@
 #include <AzQtComponents/Components/StyleManager.h>
 #include <AzQtComponents/Components/Widgets/CardHeader.h>
 
-
 #include <QApplication>
 #include <QCheckBox>
 #include <QDialog>
@@ -56,14 +55,13 @@
 #include <QVBoxLayout>
 #include <QWidget>
 
-
 namespace AzToolsFramework
 {
     namespace Prefab
     {
         ContainerEntityInterface* PrefabIntegrationManager::s_containerEntityInterface = nullptr;
         EditorEntityUiInterface* PrefabIntegrationManager::s_editorEntityUiInterface = nullptr;
-        PrefabFocusInterface* PrefabIntegrationManager::s_prefabFocusInterface = nullptr;
+        PrefabFocusPublicInterface* PrefabIntegrationManager::s_prefabFocusPublicInterface = nullptr;
         PrefabLoaderInterface* PrefabIntegrationManager::s_prefabLoaderInterface = nullptr;
         PrefabPublicInterface* PrefabIntegrationManager::s_prefabPublicInterface = nullptr;
         PrefabSystemComponentInterface* PrefabIntegrationManager::s_prefabSystemComponentInterface = nullptr;
@@ -129,10 +127,10 @@ namespace AzToolsFramework
                 return;
             }
 
-            s_prefabFocusInterface = AZ::Interface<PrefabFocusInterface>::Get();
-            if (s_prefabFocusInterface == nullptr)
+            s_prefabFocusPublicInterface = AZ::Interface<PrefabFocusPublicInterface>::Get();
+            if (s_prefabFocusPublicInterface == nullptr)
             {
-                AZ_Assert(false, "Prefab - could not get PrefabFocusInterface on PrefabIntegrationManager construction.");
+                AZ_Assert(false, "Prefab - could not get PrefabFocusPublicInterface on PrefabIntegrationManager construction.");
                 return;
             }
 
@@ -247,12 +245,8 @@ namespace AzToolsFramework
                     if (s_prefabPublicInterface->IsInstanceContainerEntity(selectedEntity))
                     {
                         // Edit Prefab
-                        if (prefabWipFeaturesEnabled)
+                        if (prefabWipFeaturesEnabled && !s_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(selectedEntity))
                         {
-                            bool beingEdited = s_prefabFocusInterface->IsOwningPrefabBeingFocused(selectedEntity);
-
-                            if (!beingEdited)
-                            {
                                 QAction* editAction = menu->addAction(QObject::tr("Edit Prefab"));
                                 editAction->setToolTip(QObject::tr("Edit the prefab in focus mode."));
 
@@ -261,7 +255,6 @@ namespace AzToolsFramework
                                 });
 
                                 itemWasShown = true;
-                            }
                         }
 
                         // Save Prefab
@@ -317,7 +310,7 @@ namespace AzToolsFramework
 
         void PrefabIntegrationManager::OnEscape()
         {
-            s_prefabFocusInterface->FocusOnOwningPrefab(AZ::EntityId());
+            s_prefabFocusPublicInterface->FocusOnOwningPrefab(AZ::EntityId());
         }
 
         void PrefabIntegrationManager::HandleSourceFileType(AZStd::string_view sourceFilePath, AZ::EntityId parentId, AZ::Vector3 position) const
@@ -490,7 +483,7 @@ namespace AzToolsFramework
 
         void PrefabIntegrationManager::ContextMenu_EditPrefab(AZ::EntityId containerEntity)
         {
-            s_prefabFocusInterface->FocusOnOwningPrefab(containerEntity);
+            s_prefabFocusPublicInterface->FocusOnOwningPrefab(containerEntity);
         }
 
         void PrefabIntegrationManager::ContextMenu_SavePrefab(AZ::EntityId containerEntity)

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabIntegrationManager.h

@@ -30,7 +30,7 @@ namespace AzToolsFramework
 
     namespace Prefab
     {
-        class PrefabFocusInterface;
+        class PrefabFocusPublicInterface;
         class PrefabLoaderInterface;
 
         //! Structure for saving/retrieving user settings related to prefab workflows.
@@ -144,7 +144,7 @@ namespace AzToolsFramework
 
             static ContainerEntityInterface* s_containerEntityInterface;
             static EditorEntityUiInterface* s_editorEntityUiInterface;
-            static PrefabFocusInterface* s_prefabFocusInterface;
+            static PrefabFocusPublicInterface* s_prefabFocusPublicInterface;
             static PrefabLoaderInterface* s_prefabLoaderInterface;
             static PrefabPublicInterface* s_prefabPublicInterface;
             static PrefabSystemComponentInterface* s_prefabSystemComponentInterface;

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabUiHandler.cpp

@@ -10,7 +10,7 @@
 
 #include <AzFramework/API/ApplicationAPI.h>
 
-#include <AzToolsFramework/Prefab/PrefabFocusInterface.h>
+#include <AzToolsFramework/Prefab/PrefabFocusPublicInterface.h>
 #include <AzToolsFramework/Prefab/PrefabPublicInterface.h>
 #include <AzToolsFramework/UI/Outliner/EntityOutlinerListModel.hxx>
 
@@ -35,10 +35,10 @@ namespace AzToolsFramework
             return;
         }
 
-        m_prefabFocusInterface = AZ::Interface<Prefab::PrefabFocusInterface>::Get();
-        if (m_prefabFocusInterface == nullptr)
+        m_prefabFocusPublicInterface = AZ::Interface<Prefab::PrefabFocusPublicInterface>::Get();
+        if (m_prefabFocusPublicInterface == nullptr)
         {
-            AZ_Assert(false, "PrefabUiHandler - could not get PrefabFocusInterface on PrefabUiHandler construction.");
+            AZ_Assert(false, "PrefabUiHandler - could not get PrefabFocusPublicInterface on PrefabUiHandler construction.");
             return;
         }
     }
@@ -83,7 +83,7 @@ namespace AzToolsFramework
 
     QIcon PrefabUiHandler::GenerateItemIcon(AZ::EntityId entityId) const
     {
-        if (m_prefabFocusInterface->IsOwningPrefabBeingFocused(entityId))
+        if (m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(entityId))
         {
             return QIcon(m_prefabEditIconPath);
         }
@@ -105,7 +105,7 @@ namespace AzToolsFramework
         const bool hasVisibleChildren = index.data(EntityOutlinerListModel::ExpandedRole).value<bool>() && index.model()->hasChildren(index);
 
         QColor backgroundColor = m_prefabCapsuleColor;
-        if (m_prefabFocusInterface->IsOwningPrefabBeingFocused(entityId))
+        if (m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(entityId))
         {
             backgroundColor = m_prefabCapsuleEditColor;
         }
@@ -191,7 +191,7 @@ namespace AzToolsFramework
         const bool isLastColumn = descendantIndex.column() == EntityOutlinerListModel::ColumnLockToggle;
 
         QColor borderColor = m_prefabCapsuleColor;
-        if (m_prefabFocusInterface->IsOwningPrefabBeingFocused(entityId))
+        if (m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(entityId))
         {
             borderColor = m_prefabCapsuleEditColor;
         }
@@ -329,7 +329,7 @@ namespace AzToolsFramework
         if (prefabWipFeaturesEnabled)
         {
             // Focus on this prefab
-            m_prefabFocusInterface->FocusOnOwningPrefab(entityId);
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(entityId);
         }
     }
 }

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabUiHandler.h

@@ -15,7 +15,7 @@ namespace AzToolsFramework
 
     namespace Prefab
     {
-        class PrefabFocusInterface;
+        class PrefabFocusPublicInterface;
         class PrefabPublicInterface;
     };
 
@@ -39,7 +39,7 @@ namespace AzToolsFramework
         void OnDoubleClick(AZ::EntityId entityId) const override;
 
     private:
-        Prefab::PrefabFocusInterface* m_prefabFocusInterface = nullptr;
+        Prefab::PrefabFocusPublicInterface* m_prefabFocusPublicInterface = nullptr;
         Prefab::PrefabPublicInterface* m_prefabPublicInterface = nullptr;
 
         static bool IsLastVisibleChild(const QModelIndex& parent, const QModelIndex& child);

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabViewportFocusPathHandler.cpp

@@ -8,7 +8,7 @@
 
 #include <AzToolsFramework/UI/Prefab/PrefabViewportFocusPathHandler.h>
 
-#include <AzToolsFramework/Prefab/PrefabFocusInterface.h>
+#include <AzToolsFramework/Prefab/PrefabFocusPublicInterface.h>
 
 namespace AzToolsFramework::Prefab
 {
@@ -31,8 +31,8 @@ namespace AzToolsFramework::Prefab
     void PrefabViewportFocusPathHandler::Initialize(AzQtComponents::BreadCrumbs* breadcrumbsWidget, QToolButton* backButton)
     {
         // Get reference to the PrefabFocusInterface handler
-        m_prefabFocusInterface = AZ::Interface<PrefabFocusInterface>::Get();
-        if (m_prefabFocusInterface == nullptr)
+        m_prefabFocusPublicInterface = AZ::Interface<PrefabFocusPublicInterface>::Get();
+        if (m_prefabFocusPublicInterface == nullptr)
         {
             AZ_Assert(false, "Prefab - could not get PrefabFocusInterface on PrefabViewportFocusPathHandler construction.");
             return;
@@ -46,7 +46,7 @@ namespace AzToolsFramework::Prefab
         connect(m_breadcrumbsWidget, &AzQtComponents::BreadCrumbs::linkClicked, this,
             [&](const QString&, int linkIndex)
             {
-                m_prefabFocusInterface->FocusOnPathIndex(m_editorEntityContextId, linkIndex);
+                m_prefabFocusPublicInterface->FocusOnPathIndex(m_editorEntityContextId, linkIndex);
             }
         );
 
@@ -54,9 +54,9 @@ namespace AzToolsFramework::Prefab
         connect(m_backButton, &QToolButton::clicked, this,
             [&]()
             {
-                if (int length = m_prefabFocusInterface->GetPrefabFocusPathLength(m_editorEntityContextId); length > 1)
+                if (int length = m_prefabFocusPublicInterface->GetPrefabFocusPathLength(m_editorEntityContextId); length > 1)
                 {
-                    m_prefabFocusInterface->FocusOnPathIndex(m_editorEntityContextId, length - 2);
+                    m_prefabFocusPublicInterface->FocusOnPathIndex(m_editorEntityContextId, length - 2);
                 }
             }
         );
@@ -65,7 +65,7 @@ namespace AzToolsFramework::Prefab
     void PrefabViewportFocusPathHandler::OnPrefabFocusChanged()
     {
         // Push new Path
-        m_breadcrumbsWidget->pushPath(m_prefabFocusInterface->GetPrefabFocusPath(m_editorEntityContextId).c_str());
+        m_breadcrumbsWidget->pushPath(m_prefabFocusPublicInterface->GetPrefabFocusPath(m_editorEntityContextId).c_str());
     }
 
 } // namespace AzToolsFramework::Prefab

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabViewportFocusPathHandler.h

@@ -19,7 +19,7 @@
 
 namespace AzToolsFramework::Prefab
 {
-    class PrefabFocusInterface;
+    class PrefabFocusPublicInterface;
 
     class PrefabViewportFocusPathHandler
         : public PrefabFocusNotificationBus::Handler
@@ -40,6 +40,6 @@ namespace AzToolsFramework::Prefab
 
         AzFramework::EntityContextId m_editorEntityContextId = AzFramework::EntityContextId::CreateNull();
 
-        PrefabFocusInterface* m_prefabFocusInterface = nullptr;
+        PrefabFocusPublicInterface* m_prefabFocusPublicInterface = nullptr;
     };
 } // namespace AzToolsFramework::Prefab

Code/Framework/AzToolsFramework/AzToolsFramework/aztoolsframework_files.cmake

@@ -646,6 +646,9 @@ set(FILES
     Prefab/PrefabFocusHandler.cpp
     Prefab/PrefabFocusInterface.h
     Prefab/PrefabFocusNotificationBus.h
+    Prefab/PrefabFocusPublicInterface.h
+    Prefab/PrefabFocusUndo.h
+    Prefab/PrefabFocusUndo.cpp
     Prefab/PrefabIdTypes.h
     Prefab/PrefabLoader.h
     Prefab/PrefabLoader.cpp

Code/Framework/AzToolsFramework/Tests/Prefab/PrefabFocus/PrefabFocusTests.cpp

@@ -10,6 +10,7 @@
 #include <AzToolsFramework/Entity/EditorEntityHelpers.h>
 #include <AzToolsFramework/Entity/PrefabEditorEntityOwnershipInterface.h>
 #include <AzToolsFramework/Prefab/PrefabFocusInterface.h>
+#include <AzToolsFramework/Prefab/PrefabFocusPublicInterface.h>
 #include <Prefab/PrefabTestFixture.h>
 
 namespace UnitTest
@@ -72,6 +73,9 @@ namespace UnitTest
             m_prefabFocusInterface = AZ::Interface<PrefabFocusInterface>::Get();
             ASSERT_TRUE(m_prefabFocusInterface != nullptr);
 
+            m_prefabFocusPublicInterface = AZ::Interface<PrefabFocusPublicInterface>::Get();
+            ASSERT_TRUE(m_prefabFocusPublicInterface != nullptr);
+
             AzToolsFramework::EditorEntityContextRequestBus::BroadcastResult(
                 m_editorEntityContextId, &AzToolsFramework::EditorEntityContextRequestBus::Events::GetEditorEntityContextId);
 
@@ -91,6 +95,7 @@ namespace UnitTest
         AZStd::unique_ptr<AzToolsFramework::Prefab::Instance> m_rootInstance;
 
         PrefabFocusInterface* m_prefabFocusInterface = nullptr;
+        PrefabFocusPublicInterface* m_prefabFocusPublicInterface = nullptr;
         AzFramework::EntityContextId m_editorEntityContextId = AzFramework::EntityContextId::CreateNull();
 
         inline static const char* CityEntityName = "City";
@@ -105,7 +110,7 @@ namespace UnitTest
     {
         // Verify FocusOnOwningPrefab works when passing the container entity of the root prefab.
         {
-            m_prefabFocusInterface->FocusOnOwningPrefab(m_instanceMap[CityEntityName]->GetContainerEntityId());
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(m_instanceMap[CityEntityName]->GetContainerEntityId());
             EXPECT_EQ(
                 m_prefabFocusInterface->GetFocusedPrefabTemplateId(m_editorEntityContextId),
                 m_instanceMap[CityEntityName]->GetTemplateId());
@@ -120,7 +125,7 @@ namespace UnitTest
     {
         // Verify FocusOnOwningPrefab works when passing a nested entity of the root prefab.
         {
-            m_prefabFocusInterface->FocusOnOwningPrefab(m_entityMap[CityEntityName]->GetId());
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(m_entityMap[CityEntityName]->GetId());
             EXPECT_EQ(
                 m_prefabFocusInterface->GetFocusedPrefabTemplateId(m_editorEntityContextId),
                 m_instanceMap[CityEntityName]->GetTemplateId());
@@ -135,7 +140,7 @@ namespace UnitTest
     {
         // Verify FocusOnOwningPrefab works when passing the container entity of a nested prefab.
         {
-            m_prefabFocusInterface->FocusOnOwningPrefab(m_instanceMap[CarEntityName]->GetContainerEntityId());
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(m_instanceMap[CarEntityName]->GetContainerEntityId());
             EXPECT_EQ(
                 m_prefabFocusInterface->GetFocusedPrefabTemplateId(m_editorEntityContextId), m_instanceMap[CarEntityName]->GetTemplateId());
 
@@ -149,7 +154,7 @@ namespace UnitTest
     {
         // Verify FocusOnOwningPrefab works when passing a nested entity of the a nested prefab.
         {
-            m_prefabFocusInterface->FocusOnOwningPrefab(m_entityMap[Passenger1EntityName]->GetId());
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(m_entityMap[Passenger1EntityName]->GetId());
             EXPECT_EQ(
                 m_prefabFocusInterface->GetFocusedPrefabTemplateId(m_editorEntityContextId), m_instanceMap[CarEntityName]->GetTemplateId());
 
@@ -169,7 +174,7 @@ namespace UnitTest
                 prefabEditorEntityOwnershipInterface->GetRootPrefabInstance();
             EXPECT_TRUE(rootPrefabInstance.has_value());
 
-            m_prefabFocusInterface->FocusOnOwningPrefab(AZ::EntityId());
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(AZ::EntityId());
             EXPECT_EQ(
                 m_prefabFocusInterface->GetFocusedPrefabTemplateId(m_editorEntityContextId), rootPrefabInstance->get().GetTemplateId());
 
@@ -183,10 +188,10 @@ namespace UnitTest
     {
         // Verify IsOwningPrefabBeingFocused returns true for all entities in a focused prefab (container/nested)
         {
-            m_prefabFocusInterface->FocusOnOwningPrefab(m_instanceMap[CityEntityName]->GetContainerEntityId());
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(m_instanceMap[CityEntityName]->GetContainerEntityId());
 
-            EXPECT_TRUE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_instanceMap[CityEntityName]->GetContainerEntityId()));
-            EXPECT_TRUE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_entityMap[CityEntityName]->GetId()));
+            EXPECT_TRUE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_instanceMap[CityEntityName]->GetContainerEntityId()));
+            EXPECT_TRUE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_entityMap[CityEntityName]->GetId()));
         }
     }
 
@@ -194,13 +199,13 @@ namespace UnitTest
     {
         // Verify IsOwningPrefabBeingFocused returns false for all entities not in a focused prefab (ancestors/descendants)
         {
-            m_prefabFocusInterface->FocusOnOwningPrefab(m_instanceMap[StreetEntityName]->GetContainerEntityId());
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(m_instanceMap[StreetEntityName]->GetContainerEntityId());
 
-            EXPECT_TRUE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_instanceMap[StreetEntityName]->GetContainerEntityId()));
-            EXPECT_FALSE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_instanceMap[CityEntityName]->GetContainerEntityId()));
-            EXPECT_FALSE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_entityMap[CityEntityName]->GetId()));
-            EXPECT_FALSE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_instanceMap[CarEntityName]->GetContainerEntityId()));
-            EXPECT_FALSE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_entityMap[Passenger1EntityName]->GetId()));
+            EXPECT_TRUE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_instanceMap[StreetEntityName]->GetContainerEntityId()));
+            EXPECT_FALSE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_instanceMap[CityEntityName]->GetContainerEntityId()));
+            EXPECT_FALSE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_entityMap[CityEntityName]->GetId()));
+            EXPECT_FALSE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_instanceMap[CarEntityName]->GetContainerEntityId()));
+            EXPECT_FALSE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_entityMap[Passenger1EntityName]->GetId()));
         }
     }
 
@@ -208,12 +213,12 @@ namespace UnitTest
     {
         // Verify IsOwningPrefabBeingFocused returns false for all entities not in a focused prefab (siblings)
         {
-            m_prefabFocusInterface->FocusOnOwningPrefab(m_instanceMap[SportsCarEntityName]->GetContainerEntityId());
+            m_prefabFocusPublicInterface->FocusOnOwningPrefab(m_instanceMap[SportsCarEntityName]->GetContainerEntityId());
 
-            EXPECT_TRUE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_instanceMap[SportsCarEntityName]->GetContainerEntityId()));
-            EXPECT_TRUE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_entityMap[Passenger2EntityName]->GetId()));
-            EXPECT_FALSE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_instanceMap[CarEntityName]->GetContainerEntityId()));
-            EXPECT_FALSE(m_prefabFocusInterface->IsOwningPrefabBeingFocused(m_entityMap[Passenger1EntityName]->GetId()));
+            EXPECT_TRUE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_instanceMap[SportsCarEntityName]->GetContainerEntityId()));
+            EXPECT_TRUE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_entityMap[Passenger2EntityName]->GetId()));
+            EXPECT_FALSE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_instanceMap[CarEntityName]->GetContainerEntityId()));
+            EXPECT_FALSE(m_prefabFocusPublicInterface->IsOwningPrefabBeingFocused(m_entityMap[Passenger1EntityName]->GetId()));
         }
     }