/*
	Copyright (C) 1996-1997  Id Software, Inc.

	This program is free software; you can redistribute it and/or modify
	it under 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 program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the Free Software
	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

	See file, 'COPYING', for details.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

static __attribute__ ((unused)) const char rcsid[] =
	"$Id$";

#ifdef HAVE_STRING_H
# include "string.h"
#endif

#include "QF/sys.h"

#include "compat.h"

#include "bsp5.h"
#include "options.h"

typedef struct wvert_s {
	vec_t       t;
	struct wvert_s *prev, *next;
} wvert_t;

typedef struct wedge_s {
	struct wedge_s *next;
	vec3_t      dir;
	vec3_t      origin;
	wvert_t     head;
} wedge_t;

int         numwedges, numwverts;
int         tjuncs;
int         tjuncfaces;
int         degenerdges;

#define	MAXWVERTS	0x20000
#define	MAXWEDGES	0x10000

wvert_t     wverts[MAXWVERTS];
wedge_t     wedges[MAXWEDGES];

#define	NUM_HASH	1024

wedge_t    *wedge_hash[NUM_HASH];

static vec3_t hash_min, hash_scale;

static void
InitHash (vec3_t mins, vec3_t maxs)
{
	int         newsize[2];
	vec3_t      size;
	vec_t       volume;
	vec_t       scale;

	VectorCopy (mins, hash_min);
	VectorSubtract (maxs, mins, size);
	memset (wedge_hash, 0, sizeof (wedge_hash));

	volume = size[0] * size[1];

	scale = sqrt (volume / NUM_HASH);

	newsize[0] = size[0] / scale;
	newsize[1] = size[1] / scale;

	hash_scale[0] = newsize[0] / size[0];
	hash_scale[1] = newsize[1] / size[1];
	hash_scale[2] = newsize[1];
}

static unsigned
HashVec (vec3_t vec)
{
	unsigned    h;

	h = hash_scale[0] * (vec[0] - hash_min[0]) * hash_scale[2]
		+ hash_scale[1] * (vec[1] - hash_min[1]);
	if (h >= NUM_HASH)
		return NUM_HASH - 1;
	return h;
}

static qboolean
CanonicalVector (vec3_t vec)
{
	vec_t       len = _VectorNormalize (vec);

	if (len < EQUAL_EPSILON)
		return false;

	if (vec[0] > EQUAL_EPSILON)
		return true;
	else if (vec[0] < -EQUAL_EPSILON) {
		VectorNegate (vec, vec);
		return true;
	} else
		vec[0] = 0;

	if (vec[1] > EQUAL_EPSILON)
		return true;
	else if (vec[1] < -EQUAL_EPSILON) {
		VectorNegate (vec, vec);
		return true;
	} else
		vec[1] = 0;

	if (vec[2] > EQUAL_EPSILON)
		return true;
	else if (vec[2] < -EQUAL_EPSILON) {
		VectorNegate (vec, vec);
		return true;
	} else
		vec[2] = 0;
	return false;
}

static wedge_t    *
FindEdge (vec3_t p1, vec3_t p2, vec_t *t1, vec_t *t2)
{
	int         h;
	vec3_t      dir, origin;
	vec_t       temp;
	wedge_t    *w;

	VectorSubtract (p2, p1, dir);

	if (!CanonicalVector (dir)) {
		degenerdges++;
		return 0;
	}

	*t1 = DotProduct (p1, dir);
	*t2 = DotProduct (p2, dir);

	VectorMultSub (p1, *t1, dir, origin);

	if (*t1 > *t2) {
		temp = *t1;
		*t1 = *t2;
		*t2 = temp;
	}

	h = HashVec (origin);

	for (w = wedge_hash[h]; w; w = w->next) {
		temp = w->origin[0] - origin[0];
		if (temp < -EQUAL_EPSILON || temp > EQUAL_EPSILON)
			continue;
		temp = w->origin[1] - origin[1];
		if (temp < -EQUAL_EPSILON || temp > EQUAL_EPSILON)
			continue;
		temp = w->origin[2] - origin[2];
		if (temp < -EQUAL_EPSILON || temp > EQUAL_EPSILON)
			continue;

		temp = w->dir[0] - dir[0];
		if (temp < -EQUAL_EPSILON || temp > EQUAL_EPSILON)
			continue;
		temp = w->dir[1] - dir[1];
		if (temp < -EQUAL_EPSILON || temp > EQUAL_EPSILON)
			continue;
		temp = w->dir[2] - dir[2];
		if (temp < -EQUAL_EPSILON || temp > EQUAL_EPSILON)
			continue;

		return w;
	}

	if (numwedges == MAXWEDGES)
		Sys_Error ("FindEdge: numwedges == MAXWEDGES");
	w = &wedges[numwedges];
	numwedges++;

	w->next = wedge_hash[h];
	wedge_hash[h] = w;

	VectorCopy (origin, w->origin);
	VectorCopy (dir, w->dir);
	w->head.next = w->head.prev = &w->head;
	w->head.t = 99999;
	return w;
}

#define	T_EPSILON	0.01

static void
AddVert (wedge_t *w, vec_t t)
{
	wvert_t    *v, *newv;

	v = w->head.next;
	do {
		if (fabs (v->t - t) < T_EPSILON)
			return;
		if (v->t > t)
			break;
		v = v->next;
	} while (1);

	// insert a new wvert before v
	if (numwverts == MAXWVERTS)
		Sys_Error ("AddVert: numwverts == MAXWVERTS");

	newv = &wverts[numwverts];
	numwverts++;

	newv->t = t;
	newv->next = v;
	newv->prev = v->prev;
	v->prev->next = newv;
	v->prev = newv;
}

static void
AddEdge (vec3_t p1, vec3_t p2)
{
	wedge_t    *w;
	vec_t       t1, t2;

	if ((w = FindEdge (p1, p2, &t1, &t2))) {
		AddVert (w, t1);
		AddVert (w, t2);
	}
}

static void
AddFaceEdges (face_t *f)
{
	int         i, j;

	for (i = 0; i < f->points->numpoints; i++) {
		j = (i + 1) % f->points->numpoints;
		AddEdge (f->points->points[i], f->points->points[j]);
	}
}

face_t     *newlist;

static void
FixFaceEdges (face_t *f)
{
	int         i, j, k;
	vec_t       t1, t2;
	wedge_t    *w;
	winding_t  *fp = f->points;
	wvert_t    *v;

  restart:
	for (i = 0; i < fp->numpoints; i++) {
		j = (i + 1) % fp->numpoints;

		if (!(w = FindEdge (fp->points[i], fp->points[j], &t1, &t2)))
			continue;

		for (v = w->head.next; v->t < t1 + T_EPSILON; v = v->next) {
		}

		if (v->t < t2 - T_EPSILON) {
			tjuncs++;
			// insert a new vertex here
			fp = realloc (fp, field_offset (winding_t,
											points[fp->numpoints + 1]));
			for (k = fp->numpoints; k > j; k--) {
				VectorCopy (fp->points[k - 1], fp->points[k]);
			}
			VectorMultAdd (w->origin, v->t, w->dir, fp->points[j]);
			fp->numpoints++;
			goto restart;
		}
	}
	f->points = fp;

	f->next = newlist;
	newlist = f;
}

//============================================================================

static void
tjunc_find_r (node_t *node)
{
	face_t     *f;

	if (node->planenum == PLANENUM_LEAF)
		return;

	for (f = node->faces; f; f = f->next)
		if (f->texturenum >= 0)
			AddFaceEdges (f);

	tjunc_find_r (node->children[0]);
	tjunc_find_r (node->children[1]);
}

static void
tjunc_fix_r (node_t *node)
{
	face_t     *next, *f;

	if (node->planenum == PLANENUM_LEAF)
		return;

	newlist = NULL;

	for (f = node->faces; f; f = next) {
		next = f->next;
		if (f->texturenum < 0)
			continue;
		FixFaceEdges (f);
	}

	node->faces = newlist;

	tjunc_fix_r (node->children[0]);
	tjunc_fix_r (node->children[1]);
}

void
tjunc (node_t *headnode)
{
	int         i;
	vec3_t      maxs, mins;

	qprintf ("---- tjunc ----\n");

	if (options.notjunc)
		return;

	// identify all points on common edges

	// origin points won't allways be inside the map, so extend the hash area 
	for (i = 0; i < 3; i++) {
		if (fabs (brushset->maxs[i]) > fabs (brushset->mins[i]))
			maxs[i] = fabs (brushset->maxs[i]);
		else
			maxs[i] = fabs (brushset->mins[i]);
	}
	VectorNegate (maxs, mins);

	InitHash (mins, maxs);

	numwedges = numwverts = 0;

	tjunc_find_r (headnode);

	qprintf ("%i world edges  %i edge points\n", numwedges, numwverts);

	// add extra vertexes on edges where needed
	tjuncs = tjuncfaces = 0;
	degenerdges = 0;

	tjunc_fix_r (headnode);

	qprintf ("%i degenerate edges\n", degenerdges);
	qprintf ("%i edges added by tjunctions\n", tjuncs);
	qprintf ("%i faces added by tjunctions\n", tjuncfaces);
}