#pragma once

#include "CoreMinimal.h"
#include "Kismet/BlueprintFunctionLibrary.h"
#include "LandscapeAuthoringLibrary.generated.h"

class ALandscape;
class ULandscapeLayerInfoObject;
class UMaterialInterface;

// One paint layer to import with the heightmap: the layer info asset the material expects and an 8-bit
// greyscale file (PNG or raw) with the same resolution as the heightmap.
USTRUCT(BlueprintType)
struct FLandscapeAuthoringWeightmap
{
	GENERATED_BODY()

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Landscape")
	TObjectPtr<ULandscapeLayerInfoObject> LayerInfo = nullptr;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Landscape")
	FString File;
};

// What the editor's "New Landscape > Import" button does, callable from an authoring script. The engine exposes
// no landscape creation to Python, so this is the project's first editor tool. Mirrors
// FLandscapeEditorDetailCustomization_NewLandscape::OnCreateButtonClicked without the regions path.
UCLASS()
class SALTYEDITOR_API ULandscapeAuthoringLibrary : public UBlueprintFunctionLibrary
{
	GENERATED_BODY()

public:
	// Creates a landscape in World from a 16-bit heightmap file, centred on Location, with the given per-quad
	// scale (cm; Z is the engine's height scale where 100 spans -256 m to +256 m). The component layout is chosen
	// from the file's resolution; a file that does not fit a layout exactly is expanded, not resampled. In a
	// world-partitioned level the landscape is split into streaming proxies of GridSize x GridSize components.
	// Returns null and logs why on failure.
	UFUNCTION(BlueprintCallable, Category = "Salty|Authoring")
	static ALandscape* CreateLandscapeFromHeightmap(UWorld* World, const FString& HeightmapFile,
		const TArray<FLandscapeAuthoringWeightmap>& Weightmaps, UMaterialInterface* Material,
		FVector Location, FVector Scale, int32 WorldPartitionGridSize = 4);

	// Creates a ULandscapeLayerInfoObject asset carrying LayerName, which is the name the landscape material
	// blends by and the name a weightmap is imported against.
	//
	// The second thing the engine exposes no Python path to, and for the same reason as the first. There is no
	// LayerInfo factory in the bindings, and ULandscapeLayerInfoObject::LayerName is VisibleAnywhere - so the
	// obvious workaround, duplicating an existing layer info, produces an asset that silently keeps the name it
	// was copied from and paints that substance wherever the new layer should be. Returns null and logs why on
	// failure; an existing asset at the path is returned rather than replaced, so this is safe to rerun.
	UFUNCTION(BlueprintCallable, Category = "Salty|Authoring")
	static ULandscapeLayerInfoObject* CreateLayerInfo(const FString& PackagePath, const FString& AssetName, FName LayerName);
};