Broad rearrangement of handlers

Plugins/BlueprintMCP/Deprecated/UMCPHandler_DeleteMaterialExpression.h

@@ -0,0 +1,126 @@
+#pragma once
+
+#include "CoreMinimal.h"
+#include "MCPHandler.h"
+#include "MCPAssetFinder.h"
+#include "MCPUtils.h"
+#include "Materials/Material.h"
+#include "Materials/MaterialExpression.h"
+#include "Materials/MaterialFunction.h"
+#include "MaterialGraph/MaterialGraph.h"
+#include "MaterialGraph/MaterialGraphNode.h"
+#include "UMCPHandler_DeleteMaterialExpression.generated.h"
+
+
+// ---------------------------------------------------------------------------
+// ---------------------------------------------------------------------------
+// ---------------------------------------------------------------------------
+
+UCLASS(meta=(Group="Unclassified"))
+class UMCPHandler_DeleteMaterialExpression : public UObject, public IMCPHandler
+{
+	GENERATED_BODY()
+
+public:
+	UPROPERTY(meta=(Optional, Description="Material name or package path (specify this or materialFunction)"))
+	FString Material;
+
+	UPROPERTY(meta=(Optional, Description="Material function name or package path (specify this or material)"))
+	FString MaterialFunction;
+
+	UPROPERTY(meta=(Description="Expression name (use FormatName from DumpMaterial output)"))
+	FString Node;
+
+	UPROPERTY(meta=(Optional, Description="If true, preview the change without applying it"))
+	bool DryRun = false;
+
+	virtual FString GetDescription() const override
+	{
+		return TEXT("Remove an expression node from a material or material function graph.");
+	}
+
+	virtual void Handle(const FJsonObject* Json, FStringBuilderBase& Result) override
+	{
+		if (Material.IsEmpty() && MaterialFunction.IsEmpty())
+		{
+			MCPErrorCallback(Result).SetError(TEXT("Specify 'material' or 'materialFunction'."));
+			return;
+		}
+
+		// Load material or material function
+		UMaterial* MaterialObj = nullptr;
+		UMaterialFunction* MatFunc = nullptr;
+
+		if (!MaterialFunction.IsEmpty())
+		{
+			MCPAssets<UMaterialFunction> MFAssets;
+			if (!MFAssets.Exact(MaterialFunction).Errors(Result).ENone().ETwo().Load()) return;
+			MatFunc = MFAssets.Object();
+		}
+		else
+		{
+			MCPAssets<UMaterial> MatAssets;
+			if (!MatAssets.Exact(Material).Errors(Result).ENone().ETwo().Load()) return;
+			MaterialObj = MatAssets.Object();
+		}
+
+		if (MaterialObj) MCPUtils::EnsureMaterialGraph(MaterialObj);
+		UEdGraph* Graph = MaterialObj ? (UEdGraph*)MaterialObj->MaterialGraph : (MatFunc ? MatFunc->MaterialGraph : nullptr);
+		if (!Graph)
+		{
+			MCPErrorCallback(Result).SetError(TEXT("Asset has no material graph."));
+			return;
+		}
+
+		// Find node by name
+		UMaterialGraphNode* TargetMatNode = nullptr;
+		for (UEdGraphNode* GraphNode : Graph->Nodes)
+		{
+			if (!GraphNode) continue;
+			UMaterialGraphNode* MatNode = Cast<UMaterialGraphNode>(GraphNode);
+			if (!MatNode || !MatNode->MaterialExpression) continue;
+			if (MCPUtils::Identifies(Node, MatNode->MaterialExpression))
+			{
+				TargetMatNode = MatNode;
+				break;
+			}
+		}
+
+		if (!TargetMatNode)
+		{
+			MCPErrorCallback(Result).SetError(FString::Printf(TEXT("Expression '%s' not found."), *Node));
+			return;
+		}
+
+		FString ExprName = MCPUtils::FormatName(TargetMatNode->MaterialExpression);
+
+		if (DryRun)
+		{
+			Result.Appendf(TEXT("DryRun: would delete %s\n"), *ExprName);
+			return;
+		}
+
+		// Remove the expression
+		UMaterialExpression* ExprToRemove = TargetMatNode->MaterialExpression;
+		if (MaterialObj)
+			MaterialObj->GetExpressionCollection().RemoveExpression(ExprToRemove);
+		else
+			MatFunc->GetExpressionCollection().RemoveExpression(ExprToRemove);
+		ExprToRemove->MarkAsGarbage();
+
+		// Rebuild graph
+		Graph->NotifyGraphChanged();
+
+		UObject* Asset = MaterialObj ? (UObject*)MaterialObj : (UObject*)MatFunc;
+		Asset->PreEditChange(nullptr);
+		Asset->PostEditChange();
+		Asset->MarkPackageDirty();
+
+		// Save
+		bool bSaved = MaterialObj ? MCPUtils::SaveMaterialPackage(MaterialObj) : MCPUtils::SaveGenericPackage(MatFunc);
+
+		Result.Appendf(TEXT("Deleted %s"), *ExprName);
+		if (!bSaved) Result.Append(TEXT(" (save failed)"));
+		Result.Append(TEXT("\n"));
+	}
+};