integration/Plugins/BlueprintMCP/Source/BlueprintMCP/Handlers/GraphNode_Create.h

#pragma once

#include "CoreMinimal.h"
#include "MCPServer.h"
#include "MCPHandler.h"
#include "MCPFetcher.h"
#include "MCPJson.h"
#include "MCPUtils.h"
#include "EdGraph/EdGraph.h"
#include "EdGraph/EdGraphNode.h"
#include "EdGraph/EdGraphSchema.h"
#include "GraphNode_Create.generated.h"


// ---------------------------------------------------------------------------
// ---------------------------------------------------------------------------
// ---------------------------------------------------------------------------

USTRUCT()
struct FSpawnNodeEntry
{
	GENERATED_BODY()

	UPROPERTY()
	FString ActionName;

	UPROPERTY()
	int32 PosX = 0;

	UPROPERTY()
	int32 PosY = 0;
};


UCLASS()
class UMCP_GraphNode_Create : public UObject, public IMCPHandler
{
	GENERATED_BODY()

public:
	UPROPERTY(meta=(Description="Path to a graph, e.g. /Game/Foo,graph:EventGraph"))
	FString Graph;

	UPROPERTY(meta=(Description="Array of {actionName, posX, posY} objects. Use GraphNodeSearchTypes to find action names."))
	FMCPJsonArray Nodes;

	virtual FString GetDescription() const override
	{
		return TEXT("Create nodes in any graph (Blueprint, Material, etc.) using the editor's action database. "
			"Can create ANY node type that appears in the editor's right-click menu. "
			"Use GraphNodeSearchTypes first to find the exact action name.");
	}

	virtual void Handle() override
	{
		MCPFetcher F;
		UEdGraph* TargetGraph = F.Walk(Graph).Cast<UEdGraph>();
		if (!TargetGraph) return;

		int32 SuccessCount = 0;
		int32 TotalCount = Nodes.Array.Num();

		for (const TSharedPtr<FJsonValue>& NodeVal : Nodes.Array)
		{
			FSpawnNodeEntry Entry;
			if (!MCPJson::PopulateFromJson(FSpawnNodeEntry::StaticStruct(), &Entry, NodeVal))
				continue;

			// Find the action by exact full name
			TArray<TSharedPtr<FEdGraphSchemaAction>> Matches = MCPUtils::SearchGraphActions(TargetGraph, Entry.ActionName, 0, /*ExactMatch=*/true);
			if (Matches.Num() == 0)
			{
				UMCPServer::Printf(TEXT("ERROR: No action found matching '%s'. Use GraphNodeSearchTypes to find available actions.\n"),
					*Entry.ActionName);
				continue;
			}
			if (Matches.Num() > 1)
			{
				UMCPServer::Printf(TEXT("ERROR: Ambiguous: %d actions match '%s'.\n"),
					Matches.Num(), *Entry.ActionName);
				continue;
			}

			// Perform the action
			FVector2D Location(Entry.PosX, Entry.PosY);
			UEdGraphNode* NewNode = Matches[0]->PerformAction(TargetGraph, nullptr, Location, /*bSelectNewNode=*/false);
			if (!NewNode)
			{
				UMCPServer::Printf(TEXT("ERROR: PerformAction returned null for '%s'.\n"), *Entry.ActionName);
				continue;
			}

			if (!NewNode->NodeGuid.IsValid())
				NewNode->CreateNewGuid();

			UMCPServer::Printf(TEXT("Spawned: %s (%s)\n"),
				*MCPUtils::FormatName(NewNode), *MCPUtils::FormatName(NewNode->GetClass()));
			SuccessCount++;
		}

		UMCPServer::Printf(TEXT("Spawned %d/%d nodes.\n"), SuccessCount, TotalCount);
	}
};