Dragging scripts onto Inspector now attempts to add it to the gameobject

Author: michaelsakharov

Prowl.Editor/GUI/Panels/InspectorPanel.cs

@@ -165,6 +165,46 @@ public override void OnGUI(Paper paper, float width, float height)
 
             paper.Box("insp_bottom_pad").Height(20);
         });
+
+        // Drag a script (.cs) from the Project panel onto the inspector to add it as a component.
+        DrawScriptComponentDropZone(paper, font, width, height);
+    }
+
+    /// <summary>
+    /// While a single GameObject is selected and a script asset that resolves to a component type is
+    /// being dragged, overlays the inspector with a drop target that adds that component on drop.
+    /// </summary>
+    private static void DrawScriptComponentDropZone(Paper paper, Scribe.FontFile font, float width, float height)
+    {
+        if (!DragDrop.IsDragging && !DragDrop.IsDropFrame) return;
+        if (DragDrop.Payload is not AssetDragPayload payload) return;
+
+        var go = Selection.ActiveObject as GameObject;
+        if (go == null || Selection.GetSelected<GameObject>().Count() != 1) return;
+
+        Type? componentType = Prowl.Editor.Projects.Scripting.ScriptComponentResolver.ResolveComponentType(payload);
+        if (componentType == null) return;
+
+        using (paper.Box("insp_script_drop")
+            .PositionType(PositionType.SelfDirected).Position(0, 0).Size(width, height)
+            .Layer(Layer.Overlay)
+            .BackgroundColor(Color.FromArgb(38, EditorTheme.Purple400))
+            .BorderColor(EditorTheme.Purple400).BorderWidth(2).Rounded(6)
+            .Enter())
+        {
+            paper.Box("insp_script_drop_lbl")
+                .Width(UnitValue.Stretch()).Height(UnitValue.Stretch()).IsNotInteractable()
+                .Text($"{EditorIcons.Plus}  {Loc.Get("inspector.add_component")}: {componentType.Name}", font)
+                .TextColor(EditorTheme.Purple400)
+                .FontSize(EditorTheme.FontSize).Alignment(TextAlignment.MiddleCenter);
+
+            // Complete the drop: the drag has ended (released) while over this overlay.
+            if (paper.IsParentHovered && !DragDrop.IsDragging)
+            {
+                Popups.AddComponentPopup.AddComponentWithUndo(go, componentType);
+                DragDrop.EndDrag();
+            }
+        }
     }
 
     private void DrawEmpty(Paper paper, Scribe.FontFile font, float width)

Prowl.Editor/GUI/Panels/ProjectPanel.cs

@@ -961,7 +961,7 @@ private Action<ContextBuilder> ItemContextMenu(ContentItem item, bool inTree = f
 
             builder.Separator();
 
-            builder.Item(Loc.Get("project.rename"), () => StartRename(item, inTree), enabled: !isMulti && !isRoot, icon: EditorIcons.PenToSquare);
+            builder.Item(Loc.Get("project.rename"), () => StartRename(item, inTree), enabled: !isMulti && !isRoot && CanRename(item), icon: EditorIcons.PenToSquare);
             builder.Item(Loc.Get("project.copy_path"), () => paper_SetClipboard(item.RelativePath), icon: EditorIcons.Copy);
             if (!item.IsFolder && item.Guid != Guid.Empty)
                 builder.Item(Loc.Get("project.copy_guid"), () => paper_SetClipboard(item.Guid.ToString()), icon: EditorIcons.Fingerprint);
@@ -1103,8 +1103,20 @@ private void DeleteSelectedItems()
         });
     }
 
+    // Renaming a .cs file only renames the file, not the class it declares, breaking the file-name =
+    // class-name convention and every serialized reference to that component type. Disabled until proper
+    // script renaming (rename the class + serialized type aliasing) is supported.
+    private static bool CanRename(ContentItem item)
+        => item.IsFolder || !string.Equals(Path.GetExtension(item.Name), ".cs", StringComparison.OrdinalIgnoreCase);
+
     private void StartRename(ContentItem item, bool inTree = false)
     {
+        if (!CanRename(item))
+        {
+            Toasts.Show(Loc.Get("toast.rename_failed"), "Renaming script files isn't supported yet - it would break the class/file-name link.", ToastType.Warning, 4f);
+            return;
+        }
+
         string id = inTree ? $"proj_folder_{item.RelativePath}" : $"proj_asset_{item.RelativePath}";
         string editName = item.IsFolder ? item.Name : Path.GetFileNameWithoutExtension(item.Name);
 

Prowl.Editor/GUI/Popups/AddComponentPopup.cs

@@ -187,17 +187,7 @@ private static void DrawComponentItem(Paper paper, Prowl.Scribe.FontFile font, s
             {
                 if (_targetGo != null)
                 {
-                    var addedComp = _targetGo.AddComponent(type);
-                    if (addedComp != null)
-                    {
-                        var compId = addedComp.Identifier;
-                        var goId = _targetGo.Identifier;
-                        var serialized = Echo.Serializer.Serialize(addedComp.GetType(), addedComp);
-                        var compType = addedComp.GetType();
-                        Undo.RegisterAction("Add Component",
-                            undo: () => { var g = Undo.FindGO(goId); if (g == null) return; var c = g.GetComponentByIdentifier(compId); if (c != null) g.RemoveComponent(c); },
-                            redo: () => { var g = Undo.FindGO(goId); if (g == null) return; var c = Echo.Serializer.Deserialize(serialized, compType) as MonoBehaviour; if (c != null) { c.Identifier = compId; g.AddComponent(c); } });
-                    }
+                    AddComponentWithUndo(_targetGo, type);
                     Close();
                 }
             })
@@ -217,6 +207,26 @@ private static void DrawComponentItem(Paper paper, Prowl.Scribe.FontFile font, s
         }
     }
 
+    /// <summary>
+    /// Adds a component of <paramref name="type"/> to <paramref name="go"/> and registers a matching
+    /// undo/redo step. Shared by the popup and the drag-a-script-onto-the-inspector path.
+    /// </summary>
+    public static MonoBehaviour? AddComponentWithUndo(GameObject go, Type type)
+    {
+        var addedComp = go.AddComponent(type);
+        if (addedComp != null)
+        {
+            var compId = addedComp.Identifier;
+            var goId = go.Identifier;
+            var serialized = Echo.Serializer.Serialize(addedComp.GetType(), addedComp);
+            var compType = addedComp.GetType();
+            Undo.RegisterAction("Add Component",
+                undo: () => { var g = Undo.FindGO(goId); if (g == null) return; var c = g.GetComponentByIdentifier(compId); if (c != null) g.RemoveComponent(c); },
+                redo: () => { var g = Undo.FindGO(goId); if (g == null) return; var c = Echo.Serializer.Deserialize(serialized, compType) as MonoBehaviour; if (c != null) { c.Identifier = compId; g.AddComponent(c); } });
+        }
+        return addedComp;
+    }
+
     private static List<ComponentEntry> GatherComponents()
     {
         var result = new List<ComponentEntry>();

Prowl.Editor/Projects/Scripting/ScriptComponentResolver.cs

@@ -0,0 +1,55 @@
+// This file is part of the Prowl Game Engine
+// Licensed under the MIT License. See the LICENSE file in the project root for details.
+
+using System;
+using System.IO;
+
+using Prowl.Editor.GUI;
+using Prowl.Runtime;
+
+namespace Prowl.Editor.Projects.Scripting;
+
+/// <summary>
+/// Maps a dragged script asset (a <c>.cs</c> file) to the component <see cref="Type"/> it defines.
+/// Scripts are not runtime assets (the importer only triggers recompilation), so the type is resolved
+/// by matching the file name against a <see cref="MonoBehaviour"/> type of the same name in the loaded
+/// assemblies - the same file-name-equals-class-name convention the script pipeline already relies on.
+/// </summary>
+public static class ScriptComponentResolver
+{
+    /// <summary>Resolve the component type a dragged asset represents, or null if it isn't a single
+    /// script file that maps to a concrete <see cref="MonoBehaviour"/>.</summary>
+    public static Type? ResolveComponentType(AssetDragPayload? payload)
+    {
+        if (payload == null || payload.IsMulti) return null;
+        return ResolveComponentType(payload.AssetName);
+    }
+
+    /// <summary>Resolve the component type for a script file name/path (must end in <c>.cs</c>).</summary>
+    public static Type? ResolveComponentType(string? fileNameOrPath)
+    {
+        if (string.IsNullOrEmpty(fileNameOrPath)) return null;
+        if (!fileNameOrPath.EndsWith(".cs", StringComparison.OrdinalIgnoreCase)) return null;
+
+        string typeName = Path.GetFileNameWithoutExtension(fileNameOrPath);
+        if (string.IsNullOrEmpty(typeName)) return null;
+
+        foreach (var assembly in AppDomain.CurrentDomain.GetAssemblies())
+        {
+            Type[] types;
+            try { types = assembly.GetTypes(); }
+            catch { continue; }
+
+            foreach (var type in types)
+            {
+                if (type.Name != typeName) continue;
+                if (type.IsAbstract) continue;
+                if (!typeof(MonoBehaviour).IsAssignableFrom(type)) continue;
+                if (type == typeof(MonoBehaviour)) continue;
+                return type;
+            }
+        }
+
+        return null;
+    }
+}