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

/*=============================================================================
        StaticMeshImportUtils.h: Static mesh import functions.
=============================================================================*/

#pragma once

#include "CoreMinimal.h"
#include "Engine/EngineTypes.h"
#include "Engine/MeshMerging.h"
#include "Engine/StaticMesh.h"
#include "PerPlatformProperties.h"

struct FMeshDescription;
class UStaticMeshSocket;
class UAssetImportData;
class UThumbnailInfo;
class UModel;
class UBodySetup;

namespace UnFbx
{
struct FBXImportOptions;
}

// LOD data to copy over
struct FExistingLODMeshData
{
    FMeshBuildSettings ExistingBuildSettings;
    FMeshReductionSettings ExistingReductionSettings;
    TUniquePtr<FMeshDescription> ExistingMeshDescription;
    TArray<FStaticMaterial> ExistingMaterials;
    FPerPlatformFloat ExistingScreenSize;
    FString ExistingSourceImportFilename;
};

struct FExistingStaticMeshData
{
    TArray<FStaticMaterial> ExistingMaterials;

    FMeshSectionInfoMap ExistingSectionInfoMap;
    TArray<FExistingLODMeshData> ExistingLODData;

    TArray<UStaticMeshSocket*> ExistingSockets;

    bool ExistingCustomizedCollision;
    bool bAutoComputeLODScreenSize;

    int32 ExistingLightMapResolution;
    int32 ExistingLightMapCoordinateIndex;

    TWeakObjectPtr<UAssetImportData> ExistingImportData;
    TWeakObjectPtr<UThumbnailInfo> ExistingThumbnailInfo;

    UModel* ExistingCollisionModel;
    UBodySetup* ExistingBodySetup;

    // A mapping of vertex positions to their color in the existing static mesh
    TMap<FVector, FColor> ExistingVertexColorData;

    float LpvBiasMultiplier;
    float BouncedSVGIBiasMultiplier;
    bool bHasNavigationData;
    FName LODGroup;
    FPerPlatformInt MinLOD;

    int32 ImportVersion;

    bool UseMaterialNameSlotWorkflow;
    // The last import material data (fbx original data before user changes)
    TArray<FName> LastImportMaterialOriginalNameData;
    TArray<TArray<FName>> LastImportMeshLodSectionMaterialData;

    bool ExistingGenerateMeshDistanceField;
    int32 ExistingLODForCollision;
    float ExistingDistanceFieldSelfShadowBias;
    bool ExistingSupportUniformlyDistributedSampling;
    bool ExistingAllowCpuAccess;
    FVector ExistingPositiveBoundsExtension;
    FVector ExistingNegativeBoundsExtension;

    UStaticMesh::FOnMeshChanged ExistingOnMeshChanged;
    UStaticMesh* ExistingComplexCollisionMesh = nullptr;

    TMap<FName, FString> ExistingUMetaDataTagValues;
};

namespace StaticMeshImportUtils
{
UNREALED_API bool DecomposeUCXMesh(const TArray<FVector>& CollisionVertices, const TArray<int32>& CollisionFaceIdx, UBodySetup* BodySetup);

/**
 *	Function for adding a box collision primitive to the supplied collision geometry based on the mesh of the box.
 *
 *	We keep a list of triangle normals found so far. For each normal direction,
 *	we should have 2 distances from the origin (2 parallel box faces). If the
 *	mesh is a box, we should have 3 distinct normal directions, and 2 distances
 *	found for each. The difference between these distances should be the box
 *	dimensions. The 3 directions give us the key axes, and therefore the
 *	box transformation matrix. This shouldn't rely on any vertex-ordering on
 *	the triangles (normals are compared +ve & -ve). It also shouldn't matter
 *	about how many triangles make up each side (but it will take longer).
 *	We get the centre of the box from the centre of its AABB.
 */
UNREALED_API bool AddBoxGeomFromTris(const TArray<FPoly>& Tris, FKAggregateGeom* AggGeom, const TCHAR* ObjName);

/**
 *	Function for adding a sphere collision primitive to the supplied collision geometry based on a set of Verts.
 *
 *	Simply put an AABB around mesh and use that to generate center and radius.
 *	It checks that the AABB is square, and that all vertices are either at the
 *	center, or within 5% of the radius distance away.
 */
UNREALED_API bool AddSphereGeomFromVerts(const TArray<FVector>& Verts, FKAggregateGeom* AggGeom, const TCHAR* ObjName);

UNREALED_API bool AddCapsuleGeomFromVerts(const TArray<FVector>& Verts, FKAggregateGeom* AggGeom, const TCHAR* ObjName);

/** Utility for adding one convex hull from the given verts */
UNREALED_API bool AddConvexGeomFromVertices(const TArray<FVector>& Verts, FKAggregateGeom* AggGeom, const TCHAR* ObjName);

UNREALED_API TSharedPtr<FExistingStaticMeshData> SaveExistingStaticMeshData(UStaticMesh* ExistingMesh, UnFbx::FBXImportOptions* ImportOptions, int32 LodIndex);

/* This function is call before building the mesh when we do a re-import*/
UNREALED_API void RestoreExistingMeshSettings(const FExistingStaticMeshData* ExistingMesh, UStaticMesh* NewMesh, int32 LODIndex);

UNREALED_API void UpdateSomeLodsImportMeshData(UStaticMesh* NewMesh, TArray<int32>* ReimportLodList);

UNREALED_API void RestoreExistingMeshData(const TSharedPtr<const FExistingStaticMeshData>& ExistingMeshDataPtr, UStaticMesh* NewMesh, int32 LodLevel, bool bCanShowDialog, bool bForceConflictingMaterialReset);
}  // namespace StaticMeshImportUtils