/*
** nodebuild.cpp
**
**---------------------------------------------------------------------------
** Copyright 2002-2016 Randy Heit
** All rights reserved.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions
** are met:
**
** 1. Redistributions of source code must retain the above copyright
**    notice, this list of conditions and the following disclaimer.
** 2. Redistributions in binary form must reproduce the above copyright
**    notice, this list of conditions and the following disclaimer in the
**    documentation and/or other materials provided with the distribution.
** 3. The name of the author may not be used to endorse or promote products
**    derived from this software without specific prior written permission.
** 4. When not used as part of ZDoom or a ZDoom derivative, this code will be
**    covered by the terms of the GNU General Public License as published by
**    the Free Software Foundation; either version 2 of the License, or (at
**    your option) any later version.
**
** THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
** OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
** IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
** INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
** NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
** THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**---------------------------------------------------------------------------
**
*/

#include "doomdata.h"
#include "tarray.h"
#include "r_defs.h"
#include "x86.h"

struct FPolySeg;
struct FMiniBSP;
struct FLevelLocals;

struct FEventInfo
{
	int Vertex;
	uint32_t FrontSeg;
};

struct FEvent
{
	FEvent *Parent, *Left, *Right;
	double Distance;
	FEventInfo Info;
};

class FEventTree
{
public:
	FEventTree ();
	~FEventTree ();

	FEvent *GetMinimum ();
	FEvent *GetSuccessor (FEvent *event) const { FEvent *node = Successor(event); return node == &Nil ? NULL : node; }
	FEvent *GetPredecessor (FEvent *event) const { FEvent *node = Predecessor(event); return node == &Nil ? NULL : node; }

	FEvent *GetNewNode ();
	void Insert (FEvent *event);
	FEvent *FindEvent (double distance) const;
	void DeleteAll ();

	void PrintTree () const { PrintTree (Root); }

private:
	FEvent Nil;
	FEvent *Root;
	FEvent *Spare;

	void DeletionTraverser (FEvent *event);
	FEvent *Successor (FEvent *event) const;
	FEvent *Predecessor (FEvent *event) const;

	void PrintTree (const FEvent *event) const;
};

struct FSimpleVert
{
	fixed_t x, y;
};

class FNodeBuilder
{
	struct FPrivSeg
	{
		int v1, v2;
		int sidedef;
		int linedef;
		sector_t *frontsector;
		sector_t *backsector;
		uint32_t next;
		uint32_t nextforvert;
		uint32_t nextforvert2;
		int loopnum;		// loop number for split avoidance (0 means splitting is okay)
		uint32_t partner;		// seg on back side
		uint32_t storedseg;	// seg # in the GL_SEGS lump

		int planenum;
		bool planefront;
		FPrivSeg *hashnext;
	};
	struct FPrivVert : FSimpleVert
	{
		uint32_t segs;		// segs that use this vertex as v1
		uint32_t segs2;	// segs that use this vertex as v2

		bool operator== (const FPrivVert &other)
		{
			return x == other.x && y == other.y;
		}
	};
	struct FSimpleLine
	{
		fixed_t x, y, dx, dy;
	};
	union USegPtr
	{
		uint32_t SegNum;
		FPrivSeg *SegPtr;
	};
	struct FSplitSharer
	{
		double Distance;
		uint32_t Seg;
		bool Forward;
	};

	struct glseg_t : public seg_t
	{
		uint32_t Partner;
	};


	// Like a blockmap, but for vertices instead of lines
	class IVertexMap
	{
	public:
		virtual ~IVertexMap();
		virtual int SelectVertexExact(FPrivVert &vert) = 0;
		virtual int SelectVertexClose(FPrivVert &vert) = 0;
	private:
		IVertexMap &operator=(const IVertexMap &);
	};

	class FVertexMap : public IVertexMap
	{
	public:
		FVertexMap (FNodeBuilder &builder, fixed_t minx, fixed_t miny, fixed_t maxx, fixed_t maxy);
		~FVertexMap ();

		int SelectVertexExact (FPrivVert &vert);
		int SelectVertexClose (FPrivVert &vert);

	private:
		FNodeBuilder &MyBuilder;
		TArray<int> *VertexGrid;

		fixed_t MinX, MinY, MaxX, MaxY;
		int BlocksWide, BlocksTall;

		enum { BLOCK_SHIFT = 8 + FRACBITS };
		enum { BLOCK_SIZE = 1 << BLOCK_SHIFT };

		int InsertVertex (FPrivVert &vert);
		inline int GetBlock (fixed_t x, fixed_t y)
		{
			assert (x >= MinX);
			assert (y >= MinY);
			assert (x <= MaxX);
			assert (y <= MaxY);
			return (unsigned(x - MinX) >> BLOCK_SHIFT) + (unsigned(y - MinY) >> BLOCK_SHIFT) * BlocksWide;
		}
	};

	class FVertexMapSimple : public IVertexMap
	{
	public:
		FVertexMapSimple(FNodeBuilder &builder);

		int SelectVertexExact(FPrivVert &vert);
		int SelectVertexClose(FPrivVert &vert);
	private:
		int InsertVertex(FPrivVert &vert);

		FNodeBuilder &MyBuilder;
	};

	friend class FVertexMap;
	friend class FVertexMapSimple;

public:
	struct FLevel
	{
		vertex_t *Vertices;		int NumVertices;
		side_t *Sides;			int NumSides;
		line_t *Lines;			int NumLines;

		fixed_t MinX, MinY, MaxX, MaxY;

		void FindMapBounds();
		void ResetMapBounds()
		{
			MinX = FIXED_MAX;
			MinY = FIXED_MAX;
			MaxX = FIXED_MIN;
			MaxY = FIXED_MIN;
		}
	};

	struct FPolyStart
	{
		int polynum;
		fixed_t x, y;
	};

	FNodeBuilder (FLevel &level);
	FNodeBuilder (FLevel &level,
		TArray<FPolyStart> &polyspots, TArray<FPolyStart> &anchors,
		bool makeGLNodes);
	~FNodeBuilder ();

	void Extract(FLevelLocals &level);
	const int *GetOldVertexTable();

	// These are used for building sub-BSP trees for polyobjects.
	void Clear();
	void AddPolySegs(FPolySeg *segs, int numsegs);
	void AddSegs(seg_t *segs, int numsegs);
	void BuildMini(bool makeGLNodes);
	void ExtractMini(FMiniBSP *bsp);

	static angle_t PointToAngle (fixed_t dx, fixed_t dy);

	//  < 0 : in front of line
	// == 0 : on line
	//  > 0 : behind line

	static inline int PointOnSide (int x, int y, int x1, int y1, int dx, int dy);

private:
	IVertexMap *VertexMap;
	int *OldVertexTable;

	TArray<node_t> Nodes;
	TArray<subsector_t> Subsectors;
	TArray<uint32_t> SubsectorSets;
	TArray<FPrivSeg> Segs;
	TArray<FPrivVert> Vertices;
	TArray<USegPtr> SegList;
	TArray<uint8_t> PlaneChecked;
	TArray<FSimpleLine> Planes;

	TArray<int> Touched;	// Loops a splitter touches on a vertex
	TArray<int> Colinear;	// Loops with edges colinear to a splitter
	FEventTree Events;		// Vertices intersected by the current splitter

	TArray<FSplitSharer> SplitSharers;	// Segs colinear with the current splitter

	uint32_t HackSeg;			// Seg to force to back of splitter
	uint32_t HackMate;			// Seg to use in front of hack seg
	FLevel &Level;
	bool GLNodes;			// Add minisegs to make GL nodes?

	// Progress meter stuff
	int SegsStuffed;

	void FindUsedVertices (vertex_t *vertices, int max);
	void BuildTree ();
	void MakeSegsFromSides ();
	int CreateSeg (int linenum, int sidenum);
	void GroupSegPlanes ();
	void GroupSegPlanesSimple ();
	void FindPolyContainers (TArray<FPolyStart> &spots, TArray<FPolyStart> &anchors);
	bool GetPolyExtents (int polynum, fixed_t bbox[4]);
	int MarkLoop (uint32_t firstseg, int loopnum);
	void AddSegToBBox (fixed_t bbox[4], const FPrivSeg *seg);
	int CreateNode (uint32_t set, unsigned int count, fixed_t bbox[4]);
	int CreateSubsector (uint32_t set, fixed_t bbox[4]);
	void CreateSubsectorsForReal ();
	bool CheckSubsector (uint32_t set, node_t &node, uint32_t &splitseg);
	bool CheckSubsectorOverlappingSegs (uint32_t set, node_t &node, uint32_t &splitseg);
	bool ShoveSegBehind (uint32_t set, node_t &node, uint32_t seg, uint32_t mate);	int SelectSplitter (uint32_t set, node_t &node, uint32_t &splitseg, int step, bool nosplit);
	void SplitSegs (uint32_t set, node_t &node, uint32_t splitseg, uint32_t &outset0, uint32_t &outset1, unsigned int &count0, unsigned int &count1);
	uint32_t SplitSeg (uint32_t segnum, int splitvert, int v1InFront);
	int Heuristic (node_t &node, uint32_t set, bool honorNoSplit);

	// Returns:
	//	0 = seg is in front
	//  1 = seg is in back
	// -1 = seg cuts the node

	int ClassifyLine (node_t &node, const FPrivVert *v1, const FPrivVert *v2, int sidev[2]);

	void FixSplitSharers (const node_t &node);
	double AddIntersection (const node_t &node, int vertex);
	void AddMinisegs (const node_t &node, uint32_t splitseg, uint32_t &fset, uint32_t &rset);
	uint32_t CheckLoopStart (fixed_t dx, fixed_t dy, int vertex1, int vertex2);
	uint32_t CheckLoopEnd (fixed_t dx, fixed_t dy, int vertex2);
	void RemoveSegFromVert1 (uint32_t segnum, int vertnum);
	void RemoveSegFromVert2 (uint32_t segnum, int vertnum);
	uint32_t AddMiniseg (int v1, int v2, uint32_t partner, uint32_t seg1, uint32_t splitseg);
	void SetNodeFromSeg (node_t &node, const FPrivSeg *pseg) const;

	int CloseSubsector (TArray<glseg_t> &segs, int subsector, vertex_t *outVerts);
	uint32_t PushGLSeg (TArray<glseg_t> &segs, const FPrivSeg *seg, vertex_t *outVerts);
	void PushConnectingGLSeg (int subsector, TArray<glseg_t> &segs, vertex_t *v1, vertex_t *v2);
	int OutputDegenerateSubsector (TArray<glseg_t> &segs, int subsector, bool bForward, double lastdot, FPrivSeg *&prev, vertex_t *outVerts);

	static int SortSegs (const void *a, const void *b);

	double InterceptVector (const node_t &splitter, const FPrivSeg &seg);

	void PrintSet (int l, uint32_t set);

	FNodeBuilder &operator= (const FNodeBuilder &) { return *this; }
};

// Points within this distance of a line will be considered on the line.
// Units are in fixed_ts.
const double SIDE_EPSILON = 6.5536;

// Vertices within this distance of each other will be considered as the same vertex.
#define VERTEX_EPSILON	6		// This is a fixed_t value

inline int FNodeBuilder::PointOnSide (int x, int y, int x1, int y1, int dx, int dy)
{
	// For most cases, a simple dot product is enough.
	double d_dx = double(dx);
	double d_dy = double(dy);
	double d_x = double(x);
	double d_y = double(y);
	double d_x1 = double(x1);
	double d_y1 = double(y1);

	double s_num = (d_y1-d_y)*d_dx - (d_x1-d_x)*d_dy;

	if (fabs(s_num) < 17179869184.f)	// 4<<32
	{
		// Either the point is very near the line, or the segment defining
		// the line is very short: Do a more expensive test to determine
		// just how far from the line the point is.
		double l = d_dx*d_dx + d_dy*d_dy;		// double l = sqrt(d_dx*d_dx+d_dy*d_dy);
		double dist = s_num * s_num / l;		// double dist = fabs(s_num)/l;
		if (dist < SIDE_EPSILON*SIDE_EPSILON)	// if (dist < SIDE_EPSILON)
		{
			return 0;
		}
	}
	return s_num > 0.0 ? -1 : 1;
}