// Lot STM1 (STM1-SPEC-11, M3 ; 1.4.3, STM1-SPEC-19 A1). Voir LPImportLandmarkMeshCommandlet.h.

#include "LPImportLandmarkMeshCommandlet.h"

#include "AssetRegistry/AssetRegistryModule.h"
#include "AutomatedAssetImportData.h"
#include "Engine/StaticMesh.h"
#include "Engine/Texture2D.h"
#include "Materials/Material.h"
#include "Factories/FbxFactory.h"
#include "Factories/FbxImportUI.h"
#include "Factories/FbxStaticMeshImportData.h"
#include "HAL/FileManager.h"
#include "MeshDescription.h"
#include "Misc/FileHelper.h"
#include "Misc/PackageName.h"
#include "StaticMeshAttributes.h"
#include "UObject/Package.h"
#include "UObject/SavePackage.h"
#include "UObject/UObjectIterator.h"

DEFINE_LOG_CATEGORY_STATIC(LogLPImportLandmarkMesh, Log, All);

namespace LPImportLandmarkMesh
{
	/** Dossier autorise : /lpm_city_<v>/(Landmarks|Houses)/<Nom> ou /Game/Heavy/StreetMap/(Landmarks|Houses)/<Nom> (Houses : 1.2.1, immeubles). */
	bool IsAllowedFolder(const FString& Folder)
	{
		if (Folder.StartsWith(TEXT("/Game/Heavy/StreetMap/Landmarks/")) || Folder.StartsWith(TEXT("/Game/Heavy/StreetMap/Houses/")))
		{
			return true;
		}
		TArray<FString> Parts;
		Folder.ParseIntoArray(Parts, TEXT("/"));
		return Parts.Num() == 3 && Parts[0].StartsWith(TEXT("lpm_city_")) && (Parts[1] == TEXT("Landmarks") || Parts[1] == TEXT("Houses"));
	}

	/** Triangles et bornes par groupe de polygones de la description source. */
	void DescribeSections(const FMeshDescription& Desc, TArray<FString>& Out)
	{
		FStaticMeshConstAttributes Attributes(Desc);
		const TPolygonGroupAttributesConstRef<FName> SlotNames = Attributes.GetPolygonGroupMaterialSlotNames();
		const TVertexAttributesConstRef<FVector3f> Positions = Attributes.GetVertexPositions();
		TMap<FPolygonGroupID, int32> Tris;
		TMap<FPolygonGroupID, FBox3f> Boxes;
		for (const FTriangleID T : Desc.Triangles().GetElementIDs())
		{
			const FPolygonGroupID G = Desc.GetTrianglePolygonGroup(T);
			Tris.FindOrAdd(G)++;
			FBox3f& Box = Boxes.FindOrAdd(G, FBox3f(ForceInit));
			for (const FVertexID V : Desc.GetTriangleVertices(T))
			{
				Box += Positions[V];
			}
		}
		for (const FPolygonGroupID G : Desc.PolygonGroups().GetElementIDs())
		{
			const FBox3f Box = Boxes.FindRef(G);
			Out.Add(FString::Printf(TEXT("| %d | %s | %d | (%.0f, %.0f, %.0f) a (%.0f, %.0f, %.0f) |"), G.GetValue(), *SlotNames[G].ToString(), Tris.FindRef(G),
				Box.Min.X, Box.Min.Y, Box.Min.Z, Box.Max.X, Box.Max.Y, Box.Max.Z));
		}
	}
}

ULPImportLandmarkMeshCommandlet::ULPImportLandmarkMeshCommandlet()
{
	IsClient = false;
	IsServer = false;
	IsEditor = true;
	LogToConsole = true;
}

int32 ULPImportLandmarkMeshCommandlet::Main(const FString& Params)
{
	using namespace LPImportLandmarkMesh;

	TArray<FString> Tokens, Switches;
	TMap<FString, FString> ParamsMap;
	ParseCommandLine(*Params, Tokens, Switches, ParamsMap);
	const FString FbxPath = ParamsMap.FindRef(TEXT("Fbx"));
	const FString PackageName = ParamsMap.FindRef(TEXT("Package"));
	const FString ReportPath = ParamsMap.FindRef(TEXT("Report"));
	const int32 MaxTriangles = ParamsMap.Contains(TEXT("MaxTriangles")) ? FCString::Atoi(*ParamsMap[TEXT("MaxTriangles")]) : 20000;
	const int32 MaxTexture = ParamsMap.Contains(TEXT("MaxTexture")) ? FCString::Atoi(*ParamsMap[TEXT("MaxTexture")]) : 2048;
	TArray<FString> RemoveText;
	ParamsMap.FindRef(TEXT("RemoveSections")).ParseIntoArray(RemoveText, TEXT(","));
	// 1.2.1 : LOD supplementaires, budgets de triangles decroissants (ex. -Lods=400,80), reduits depuis le LOD0 source.
	TArray<FString> LodText;
	ParamsMap.FindRef(TEXT("Lods")).ParseIntoArray(LodText, TEXT(","));
	// 1.4.3 : -Materials=<emplacement>=<objet>;... : materiaux existants poses sur les emplacements du FBX (ni materiau ni
	// texture importes) ; les variantes d'un meme modele partagent ainsi les materiaux et les textures du premier import.
	TMap<FString, FString> SlotMaterials;
	{
		TArray<FString> Pairs;
		ParamsMap.FindRef(TEXT("Materials")).ParseIntoArray(Pairs, TEXT(";"));
		for (const FString& Pair : Pairs)
		{
			FString Key, Value;
			if (Pair.Split(TEXT("="), &Key, &Value)) SlotMaterials.Add(Key, Value);
		}
	}

	TArray<FString> Report;
	auto Line = [&Report](const FString& Text)
	{
		UE_LOG(LogLPImportLandmarkMesh, Display, TEXT("%s"), *Text);
		Report.Add(Text);
	};
	auto Finish = [&](int32 Code)
	{
		Line(FString::Printf(TEXT("CODE %d"), Code));
		if (!ReportPath.IsEmpty())
		{
			FFileHelper::SaveStringArrayToFile(Report, *ReportPath, FFileHelper::EEncodingOptions::ForceUTF8WithoutBOM);
		}
		return Code;
	};

	if (FbxPath.IsEmpty() || PackageName.IsEmpty())
	{
		Line(TEXT("usage : -Fbx=<fichier .fbx ou .obj> -Package=</lpm_city_<v>/(Landmarks|Houses)/<Nom>/<Nom>> [-MaxTriangles=20000] [-Lods=<t1>,<t2>] [-MaxTexture=2048] [-RemoveSections=<i>,<j>] [-Materials=<emplacement>=<objet>;...] [-Report=<f.md>]"));
		return Finish(2);
	}
	const FString Folder = FPackageName::GetLongPackagePath(PackageName);
	const FString AssetName = FPackageName::GetLongPackageAssetName(PackageName);
	Line(FString::Printf(TEXT("# LPImportLandmarkMesh %s <- %s"), *PackageName, *FbxPath));
	if (!IsAllowedFolder(Folder) || !FPackageName::IsValidLongPackageName(PackageName))
	{
		Line(TEXT("ECHEC : dossier hors de /lpm_city_*/(Landmarks|Houses)/<Nom> et de /Game/Heavy/StreetMap/(Landmarks|Houses)/ ; rien importe"));
		return Finish(1);
	}
	TArray<FAssetData> Existing;
	IAssetRegistry& Registry = FModuleManager::LoadModuleChecked<FAssetRegistryModule>(TEXT("AssetRegistry")).Get();
	Registry.ScanPathsSynchronous({ Folder }, /*bForceRescan=*/true);
	Registry.GetAssetsByPath(FName(*Folder), Existing, true);
	if (!Existing.IsEmpty() || FPackageName::DoesPackageExist(PackageName))
	{
		Line(FString::Printf(TEXT("ECHEC : le dossier %s n'est pas neuf (%d asset(s)) ; rien importe"), *Folder, Existing.Num()));
		return Finish(1);
	}
	const int64 FbxBytes = IFileManager::Get().FileSize(*FbxPath);
	if (FbxBytes <= 0)
	{
		Line(TEXT("ECHEC : FBX introuvable ou vide"));
		return Finish(1);
	}

	// Import automatise (aucune boite de dialogue), un seul maillage statique, materiaux et textures.
	UFbxFactory* Factory = NewObject<UFbxFactory>(GetTransientPackage());
	Factory->AddToRoot();
	UAutomatedAssetImportData* Automated = NewObject<UAutomatedAssetImportData>(GetTransientPackage());
	Automated->DestinationPath = Folder;
	Automated->bReplaceExisting = false;
	Factory->SetAutomatedAssetImportData(Automated);
	Factory->ImportUI->bImportAsSkeletal = false;
	Factory->ImportUI->bImportAnimations = false;
	Factory->ImportUI->bImportMesh = true;
	Factory->ImportUI->bImportMaterials = SlotMaterials.IsEmpty();
	Factory->ImportUI->bImportTextures = SlotMaterials.IsEmpty();
	Factory->ImportUI->bAutomatedImportShouldDetectType = false;
	Factory->ImportUI->MeshTypeToImport = FBXIT_StaticMesh;
	Factory->ImportUI->StaticMeshImportData->bCombineMeshes = true;
	Factory->ImportUI->StaticMeshImportData->bAutoGenerateCollision = false;
	Factory->ImportUI->StaticMeshImportData->bGenerateLightmapUVs = false;

	UPackage* Package = CreatePackage(*PackageName);
	bool bCanceled = false;
	UObject* Imported = Factory->ImportObject(UStaticMesh::StaticClass(), Package, *AssetName, RF_Public | RF_Standalone, FbxPath, nullptr, bCanceled);
	Factory->RemoveFromRoot();
	UStaticMesh* Mesh = Cast<UStaticMesh>(Imported);
	if (!Mesh || bCanceled)
	{
		Line(FString::Printf(TEXT("ECHEC : import (%s) ; FBX %lld octets"), bCanceled ? TEXT("annule") : TEXT("pas de maillage statique"), FbxBytes));
		return Finish(1);
	}

	FMeshDescription* Desc = Mesh->GetMeshDescription(0);
	const FBox Bounds = Mesh->GetBoundingBox();
	Line(FString::Printf(TEXT("importe : FBX %lld octets ; %d section(s) ; description %d triangles ; bornes (%.0f, %.0f, %.0f) a (%.0f, %.0f, %.0f) cm ; taille %.0f x %.0f x %.0f cm"),
		FbxBytes, Mesh->GetStaticMaterials().Num(), Desc ? Desc->Triangles().Num() : -1, Bounds.Min.X, Bounds.Min.Y, Bounds.Min.Z, Bounds.Max.X, Bounds.Max.Y, Bounds.Max.Z,
		Bounds.GetSize().X, Bounds.GetSize().Y, Bounds.GetSize().Z));
	if (Desc)
	{
		Line(TEXT("| section | materiau | triangles | bornes (cm) |"));
		Line(TEXT("|---|---|---|---|"));
		DescribeSections(*Desc, Report);
	}
	if (Switches.Contains(TEXT("InspectOnly")))
	{
		Line(TEXT("InspectOnly : rien enregistre (import en memoire seulement)"));
		return Finish(0);
	}

	// 1.4.3 : materiaux existants sur les emplacements nommes (tous les emplacements doivent etre couverts).
	if (!SlotMaterials.IsEmpty())
	{
		for (FStaticMaterial& Slot : Mesh->GetStaticMaterials())
		{
			const FString SlotName = Slot.ImportedMaterialSlotName.ToString();
			const FString* Path = SlotMaterials.Find(SlotName);
			UMaterialInterface* Material = Path ? LoadObject<UMaterialInterface>(nullptr, **Path) : nullptr;
			if (!Material)
			{
				Line(FString::Printf(TEXT("ECHEC : emplacement %s sans materiau existant (%s) ; rien enregistre"), *SlotName, Path ? **Path : TEXT("absent de -Materials")));
				return Finish(1);
			}
			Slot.MaterialInterface = Material;
			Line(FString::Printf(TEXT("emplacement %s -> %s"), *SlotName, *Material->GetPathName()));
		}
	}

	// Retrait de sections (par exemple la pyramide du Louvre, oeuvre protegee).
	if (Desc && !RemoveText.IsEmpty())
	{
		TArray<FPolygonID> ToDelete;
		for (const FString& Text : RemoveText)
		{
			const FPolygonGroupID Group(FCString::Atoi(*Text));
			if (!Desc->IsPolygonGroupValid(Group)) { Line(FString::Printf(TEXT("ECHEC : section %s inconnue ; rien enregistre"), *Text)); return Finish(1); }
			ToDelete.Append(Desc->GetPolygonGroupPolygonIDs(Group));
		}
		TArray<FEdgeID> OrphanEdges;
		TArray<FVertexInstanceID> OrphanInstances;
		for (const FPolygonID Polygon : ToDelete) Desc->DeletePolygon(Polygon, &OrphanEdges, &OrphanInstances, nullptr);
		for (const FVertexInstanceID I : OrphanInstances) if (Desc->IsVertexInstanceValid(I)) Desc->DeleteVertexInstance(I);
		for (const FEdgeID E : OrphanEdges) if (Desc->IsEdgeValid(E)) Desc->DeleteEdge(E);
		Mesh->CommitMeshDescription(0);
		Line(FString::Printf(TEXT("sections retirees : %s (%d polygones) ; reste %d triangles"), *FString::Join(RemoveText, TEXT(",")), ToDelete.Num(), Desc->Triangles().Num()));
	}

	// Reduction du LOD0 au budget, puis construction.
	const int32 SourceTris = Desc ? Desc->Triangles().Num() : 0;
	if (SourceTris > MaxTriangles && MaxTriangles > 0)
	{
		FStaticMeshSourceModel& Source = Mesh->GetSourceModel(0);
		Source.ReductionSettings.TerminationCriterion = EStaticMeshReductionTerimationCriterion::Triangles;
		Source.ReductionSettings.PercentTriangles = float(MaxTriangles) / float(SourceTris);
		Source.ReductionSettings.MaxNumOfTriangles = uint32(MaxTriangles);
	}
	if (!LodText.IsEmpty() && SourceTris > 0)
	{
		// La reduction d'un LOD part du LOD0 deja reduit : le pourcentage se calcule sur son budget.
		const int32 Lod0Tris = (MaxTriangles > 0) ? FMath::Min(SourceTris, MaxTriangles) : SourceTris;
		TArray<FString> ScreenText;
		ParamsMap.FindRef(TEXT("LodScreen")).ParseIntoArray(ScreenText, TEXT(","));
		Mesh->SetNumSourceModels(1 + LodText.Num());
		Mesh->SetAutoComputeLODScreenSize(false);
		Mesh->GetSourceModel(0).ScreenSize = 1.f;
		for (int32 L = 0; L < LodText.Num(); ++L)
		{
			const int32 Budget = FMath::Max(1, FCString::Atoi(*LodText[L]));
			FStaticMeshSourceModel& Lod = Mesh->GetSourceModel(1 + L);
			Lod.BuildSettings = Mesh->GetSourceModel(0).BuildSettings;
			Lod.ReductionSettings.BaseLODModel = 0;
			Lod.ReductionSettings.TerminationCriterion = EStaticMeshReductionTerimationCriterion::Triangles;
			Lod.ReductionSettings.PercentTriangles = FMath::Min(1.f, float(Budget) / float(Lod0Tris));
			Lod.ReductionSettings.MaxNumOfTriangles = uint32(Budget);
			// Tailles d'ecran : -LodScreen=<s1>,<s2> ; par defaut 0,25 puis divisee par 3 a chaque LOD.
			Lod.ScreenSize = ScreenText.IsValidIndex(L) ? FCString::Atof(*ScreenText[L]) : 0.25f / FMath::Pow(3.f, float(L));
		}
	}
	Mesh->Build(/*bSilent=*/true);
	Mesh->PostEditChange();
	const int32 LodTris = Mesh->GetRenderData() && Mesh->GetRenderData()->LODResources.Num() ? Mesh->GetRenderData()->LODResources[0].GetNumTriangles() : -1;
	Line(FString::Printf(TEXT("LOD0 rendu : %d triangles (source %d, budget %d)"), LodTris, SourceTris, MaxTriangles));
	for (int32 L = 1; Mesh->GetRenderData() && L < Mesh->GetRenderData()->LODResources.Num(); ++L)
	{
		Line(FString::Printf(TEXT("LOD%d rendu : %d triangles (budget %s) ; taille d'ecran %.3f"), L, Mesh->GetRenderData()->LODResources[L].GetNumTriangles(),
			LodText.IsValidIndex(L - 1) ? *LodText[L - 1] : TEXT("-"), Mesh->GetRenderData()->ScreenSize[L].Default));
	}

	// Textures du dossier : plafond de taille. Enregistrement de tous les paquets du dossier.
	int32 Textures = 0, Saved = 0;
	TArray<UPackage*> Packages;
	for (TObjectIterator<UObject> It; It; ++It)
	{
		UPackage* Outer = It->GetPackage();
		if (!Outer || !Outer->GetName().StartsWith(Folder + TEXT("/")) || !It->IsAsset()) continue;
		// 1.2.2 : les immeubles sont poses en HISM ; sans ce drapeau, le jeu cuit retombe sur le materiau par defaut.
		if (UMaterial* Material = Cast<UMaterial>(*It); Material && Folder.Contains(TEXT("/Houses/")) && !Material->GetUsageByFlag(MATUSAGE_InstancedStaticMeshes))
		{
			Material->SetUsageByFlag(MATUSAGE_InstancedStaticMeshes, true);
			Material->PostEditChange();
			Line(FString::Printf(TEXT("materiau %s : bUsedWithInstancedStaticMeshes coche"), *Material->GetName()));
		}
		if (UTexture2D* Texture = Cast<UTexture2D>(*It))
		{
			Texture->MaxTextureSize = MaxTexture;
			Texture->PostEditChange();
			++Textures;
			Line(FString::Printf(TEXT("texture %s : source %d x %d, plafond %d"), *Texture->GetName(), Texture->Source.GetSizeX(), Texture->Source.GetSizeY(), MaxTexture));
		}
		Packages.AddUnique(Outer);
	}
	for (UPackage* Pkg : Packages)
	{
		UObject* Main = Pkg->FindAssetInPackage();
		if (!Main) continue;
		FAssetRegistryModule::AssetCreated(Main);
		FSavePackageArgs SaveArgs;
		SaveArgs.TopLevelFlags = RF_Public | RF_Standalone;
		const FString File = FPackageName::LongPackageNameToFilename(Pkg->GetName(), FPackageName::GetAssetPackageExtension());
		if (!UPackage::SavePackage(Pkg, Main, *File, SaveArgs))
		{
			Line(FString::Printf(TEXT("ECHEC : sauvegarde de %s"), *Pkg->GetName()));
			return Finish(1);
		}
		++Saved;
		Line(FString::Printf(TEXT("ecrit : %s (%s), %lld octets"), *Pkg->GetName(), *Main->GetClass()->GetName(), IFileManager::Get().FileSize(*File)));
	}
	Line(FString::Printf(TEXT("textures plafonnees %d ; paquets ecrits %d"), Textures, Saved));
	return Finish(0);
}