#pragma once

#include "hw_levelmesh.h"
#include "tarray.h"
#include "vectors.h"
#include "r_defs.h"
#include "bounds.h"
#include <dp_rect_pack.h>

#include <set>

typedef dp::rect_pack::RectPacker<int> RectPacker;

struct FLevelLocals;

struct DoomLevelMeshSurface : public LevelMeshSurface
{
	subsector_t* Subsector = nullptr;
	side_t* Side = nullptr;
	sector_t* ControlSector = nullptr;
	float* TexCoords;
};

class DoomLevelMesh : public LevelMesh
{
public:
	DoomLevelMesh(FLevelLocals &doomMap);
	
	void CreatePortals();
	void DumpMesh(const FString& objFilename, const FString& mtlFilename) const;
	void BindLightmapSurfacesToGeometry(FLevelLocals& doomMap);
	void PackLightmapAtlas();

	bool TraceSky(const FVector3& start, FVector3 direction, float dist)
	{
		FVector3 end = start + direction * dist;
		auto surface = Trace(start, direction, dist);
		return surface && surface->bSky;
	}

	void UpdateLightLists() override;

	LevelMeshSurface* GetSurface(int index) override { return &Surfaces[index]; }
	unsigned int GetSurfaceIndex(const LevelMeshSurface* surface) const override { return (unsigned int)(ptrdiff_t)(static_cast<const DoomLevelMeshSurface*>(surface) - Surfaces.Data()); }
	int GetSurfaceCount() override { return Surfaces.Size(); }


	TArray<DoomLevelMeshSurface> Surfaces;
	std::vector<std::unique_ptr<LevelMeshLight>> Lights;
	TArray<FVector2> LightmapUvs;
	static_assert(alignof(FVector2) == alignof(float[2]) && sizeof(FVector2) == sizeof(float) * 2);

	// utility
	TArray<int> sectorGroup; // index is sector, value is sectorGroup

	// runtime utility variables
	TMap<const sector_t*, TArray<DoomLevelMeshSurface*>> XFloorToSurface;
	TMap<const sector_t*, TArray<DoomLevelMeshSurface*>> XFloorToSurfaceSides;

private:
	void BuildSectorGroups(const FLevelLocals& doomMap);

	void CreateSubsectorSurfaces(FLevelLocals &doomMap);
	void CreateCeilingSurface(FLevelLocals& doomMap, subsector_t* sub, sector_t* sector, sector_t* controlSector, int typeIndex);
	void CreateFloorSurface(FLevelLocals& doomMap, subsector_t* sub, sector_t* sector, sector_t* controlSector, int typeIndex);
	void CreateSideSurfaces(FLevelLocals &doomMap, side_t *side);

	void SetSubsectorLightmap(DoomLevelMeshSurface* surface);
	void SetSideLightmap(DoomLevelMeshSurface* surface);

	void SetupLightmapUvs();
	void PropagateLight(const LevelMeshLight* light, std::set<LevelMeshPortal, RecursivePortalComparator>& touchedPortals, int lightPropagationRecursiveDepth);
	void CreateLightList();


	static bool IsTopSideSky(sector_t* frontsector, sector_t* backsector, side_t* side);
	static bool IsTopSideVisible(side_t* side);
	static bool IsBottomSideVisible(side_t* side);
	static bool IsSkySector(sector_t* sector, int plane);
	static bool IsControlSector(sector_t* sector);

	static FVector4 ToPlane(const FVector3& pt1, const FVector3& pt2, const FVector3& pt3)
	{
		FVector3 n = ((pt2 - pt1) ^ (pt3 - pt2)).Unit();
		float d = pt1 | n;
		return FVector4(n.X, n.Y, n.Z, d);
	}

	static FVector4 ToPlane(const FVector3& pt1, const FVector3& pt2, const FVector3& pt3, const FVector3& pt4)
	{
		if (pt1.ApproximatelyEquals(pt3))
		{
			return ToPlane(pt1, pt2, pt4);
		}
		else if(pt1.ApproximatelyEquals(pt2) || pt2.ApproximatelyEquals(pt3))
		{
			return ToPlane(pt1, pt3, pt4);
		}

		return ToPlane(pt1, pt2, pt3);
	}

	static FVector2 ToFVector2(const DVector2& v) { return FVector2((float)v.X, (float)v.Y); }
	static FVector3 ToFVector3(const DVector3& v) { return FVector3((float)v.X, (float)v.Y, (float)v.Z); }
	static FVector4 ToFVector4(const DVector4& v) { return FVector4((float)v.X, (float)v.Y, (float)v.Z, (float)v.W); }

	static bool IsDegenerate(const FVector3 &v0, const FVector3 &v1, const FVector3 &v2);

	// WIP internal lightmapper

	enum PlaneAxis
	{
		AXIS_YZ = 0,
		AXIS_XZ,
		AXIS_XY
	};

	static PlaneAxis BestAxis(const FVector4& p);
	BBox GetBoundsFromSurface(const LevelMeshSurface& surface) const;

	inline int AllocUvs(int amount) { return LightmapUvs.Reserve(amount); }

	void BuildSurfaceParams(int lightMapTextureWidth, int lightMapTextureHeight, LevelMeshSurface& surface);
	void FinishSurface(int lightmapTextureWidth, int lightmapTextureHeight, RectPacker& packer, LevelMeshSurface& surface);
};