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

#pragma once

#include "CoreMinimal.h"
#include "MCPHandler.h"
#include "MCPFetcher.h"
#include "MCPUtils.h"
#include "Kismet2/KismetEditorUtilities.h"
#include "Animation/AnimBlueprint.h"
#include "AnimStateNode.h"
#include "AnimStateTransitionNode.h"
#include "AnimationStateMachineGraph.h"
#include "StateMachine_RemoveState.generated.h"


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

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

public:
	UPROPERTY(meta=(Description="Path to the state machine graph, e.g. /Game/MyAnimBP,graph:StateMachine"))
	FString Path;

	UPROPERTY(meta=(Description="Name of the state to remove"))
	FString StateName;

	virtual FString GetDescription() const override
	{
		return TEXT("Remove a state and its connected transitions from an animation state machine graph.");
	}

	virtual void Handle(FStringBuilderBase& Result) override
	{
		// Fetch the state machine graph via MCPFetcher
		MCPFetcher F;
		F.Walk(Path);
		if (!F.Ok()) return;

		UAnimationStateMachineGraph* SMGraph = F.Cast<UAnimationStateMachineGraph>();
		if (!SMGraph) return;

		// Find the owning AnimBlueprint for compile/save
		UBlueprint* BP = Cast<UBlueprint>(SMGraph->GetOuter()->GetOuter());
		if (!BP)
		{
			Result.Append(TEXT("ERROR: Could not find owning blueprint.\n"));
			return;
		}

		// Find the state node
		UAnimStateNode* StateNode = MCPUtils::FindStateByName(SMGraph, StateName, Result);
		if (!StateNode) return;

		// Collect and remove transitions connected to this state
		int32 RemovedTransitions = 0;
		for (UEdGraphNode* Node : TArray<UEdGraphNode*>(SMGraph->Nodes))
		{
			UAnimStateTransitionNode* TransNode = Cast<UAnimStateTransitionNode>(Node);
			if (!TransNode) continue;
			if (TransNode->GetPreviousState() != StateNode && TransNode->GetNextState() != StateNode) continue;
			TransNode->BreakAllNodeLinks();
			SMGraph->RemoveNode(TransNode);
			RemovedTransitions++;
		}

		// Remove the state
		StateNode->BreakAllNodeLinks();
		SMGraph->RemoveNode(StateNode);

		// Compile and save
		FKismetEditorUtilities::CompileBlueprint(BP);
		MCPUtils::SaveBlueprintPackage(BP);

		Result.Appendf(TEXT("Removed state %s and %d transition(s).\n"),
			*MCPUtils::FormatName(StateNode), RemovedTransitions);
	}
};