#pragma once

#include "CoreMinimal.h"
#include "MCPHandler.h"
#include "MCPAssets.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"));
	}
};