// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "MultiSelectionTool.h"
#include "InteractiveToolBuilder.h"
#include "MultiSelectionMeshEditingTool.generated.h"

class UMultiSelectionMeshEditingTool;

/**
 * UMultiSelectionMeshEditingToolBuilder is a base tool builder for multi
 * selection tools that define a common set of ToolTarget interfaces required
 * for editing meshes.
 */
UCLASS(Transient, Abstract)
class MODELINGCOMPONENTS_API UMultiSelectionMeshEditingToolBuilder : public UInteractiveToolWithToolTargetsBuilder
{
	GENERATED_BODY()

public:
	/** @return true if mesh sources can be found in the active selection */
	virtual bool CanBuildTool(const FToolBuilderState& SceneState) const override;

	/** @return new Tool instance initialized with selected mesh source(s) */
	virtual UInteractiveTool* BuildTool(const FToolBuilderState& SceneState) const override;

	/** @return new Tool instance. Override this in subclasses to build a different Tool class type */
	virtual UMultiSelectionMeshEditingTool* CreateNewTool(const FToolBuilderState& SceneState) const PURE_VIRTUAL(UMultiSelectionMeshEditingToolBuilder::CreateNewTool, return nullptr; );

	/** Called by BuildTool to configure the Tool with the input mesh source(s) based on the SceneState */
	virtual void InitializeNewTool(UMultiSelectionMeshEditingTool* Tool, const FToolBuilderState& SceneState) const;

protected:
	virtual const FToolTargetTypeRequirements& GetTargetRequirements() const override;
};


/**
 * Multi Selection Mesh Editing tool base class.
 */
UCLASS()
class MODELINGCOMPONENTS_API UMultiSelectionMeshEditingTool : public UMultiSelectionTool
{
	GENERATED_BODY()
public:
	virtual void SetWorld(UWorld* World) { TargetWorld = World; }
	virtual UWorld* GetTargetWorld() { return TargetWorld; }

	/**
	 * Helper to find which targets share source data.
	 * Requires UAssetBackedTarget as a tool target requirement.
	 *
	 * @return Array of indices, 1:1 with Targets, indicating the first index where a component target sharing the same source data appeared.
	 */
	bool GetMapToSharedSourceData(TArray<int32>& MapToFirstOccurrences);

protected:
	UPROPERTY()
	TObjectPtr<UWorld> TargetWorld = nullptr;
};