/*
 * Copyright (C) 1997-2001 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.
 *
 */
/* world.c -- world query functions */

#include "server.h"

/*
 *
 * ============================================================================
 * ===
 *
 * ENTITY AREA CHECKING
 *
 * FIXME: this use of "area" is different from the bsp file use
 * ===========================================================================
 * ====
 */

/* (type *)STRUCT_FROM_LINK(link_t *link, type, member) */
/* ent = STRUCT_FROM_LINK(link,entity_t,order) */
/* FIXME: remove this mess! */
#define	STRUCT_FROM_LINK(l,t,m) ((t *)((byte *)l - (int)&(((t *)0)->m)))

#define	EDICT_FROM_AREA(l) STRUCT_FROM_LINK(l,edict_t,area)

typedef struct areanode_s {
	int		axis;	/* -1 = leaf node */
	float		dist;
	struct areanode_s *children[2];
	link_t		trigger_edicts;
	link_t		solid_edicts;
} areanode_t;

#define	AREA_DEPTH	4
#define	AREA_NODES	32

areanode_t	sv_areanodes[AREA_NODES];
int		sv_numareanodes;

float          *area_mins, *area_maxs;
edict_t       **area_list;
int		area_count, area_maxcount;
int		area_type;

int		SV_HullForEntity(edict_t * ent);


/* ClearLink is used for new headnodes */
void
ClearLink(link_t * l)
{
	l->prev = l->next = l;
}

void
RemoveLink(link_t * l)
{
	l->next->prev = l->prev;
	l->prev->next = l->next;
}

void
InsertLinkBefore(link_t * l, link_t * before)
{
	l->next = before;
	l->prev = before->prev;
	l->prev->next = l;
	l->next->prev = l;
}

/*
 * =============== SV_CreateAreaNode
 *
 * Builds a uniformly subdivided tree for the given world size ===============
 */
areanode_t     *
SV_CreateAreaNode(int depth, vec3_t mins, vec3_t maxs)
{
	areanode_t     *anode;
	vec3_t		size;
	vec3_t		mins1, maxs1, mins2, maxs2;

	anode = &sv_areanodes[sv_numareanodes];
	sv_numareanodes++;

	ClearLink(&anode->trigger_edicts);
	ClearLink(&anode->solid_edicts);

	if (depth == AREA_DEPTH) {
		anode->axis = -1;
		anode->children[0] = anode->children[1] = NULL;
		return anode;
	}
	VectorSubtract(maxs, mins, size);
	if (size[0] > size[1])
		anode->axis = 0;
	else
		anode->axis = 1;

	anode->dist = 0.5 * (maxs[anode->axis] + mins[anode->axis]);
	VectorCopy(mins, mins1);
	VectorCopy(mins, mins2);
	VectorCopy(maxs, maxs1);
	VectorCopy(maxs, maxs2);

	maxs1[anode->axis] = mins2[anode->axis] = anode->dist;

	anode->children[0] = SV_CreateAreaNode(depth + 1, mins2, maxs2);
	anode->children[1] = SV_CreateAreaNode(depth + 1, mins1, maxs1);

	return anode;
}

/*
 * =============== SV_ClearWorld
 *
 * ===============
 */
void
SV_ClearWorld(void)
{
	memset(sv_areanodes, 0, sizeof(sv_areanodes));
	sv_numareanodes = 0;
	SV_CreateAreaNode(0, sv.models[1]->mins, sv.models[1]->maxs);
}


/*
 * =============== SV_UnlinkEdict
 *
 * ===============
 */
void
SV_UnlinkEdict(edict_t * ent)
{
	if (!ent->area.prev)
		return;		/* not linked in anywhere */
	RemoveLink(&ent->area);
	ent->area.prev = ent->area.next = NULL;
}


/*
 * =============== SV_LinkEdict
 *
 * ===============
 */
#define MAX_TOTAL_ENT_LEAFS		128
void
SV_LinkEdict(edict_t * ent)
{
	areanode_t     *node;
	int		leafs[MAX_TOTAL_ENT_LEAFS];
	int		clusters[MAX_TOTAL_ENT_LEAFS];
	int		num_leafs;
	int		i, j, k;
	int		area;
	int		topnode;

	if (ent->area.prev)
		SV_UnlinkEdict(ent);	/* unlink from old position */

	if (ent == ge->edicts)
		return;		/* don't add the world */

	if (!ent->inuse)
		return;

	/* set the size */
	VectorSubtract(ent->maxs, ent->mins, ent->size);

	/* encode the size into the entity_state for client prediction */
	if (ent->solid == SOLID_BBOX && !(ent->svflags & SVF_DEADMONSTER)) {	/* assume that x/y are
										 * equal and symetric */
		i = ent->maxs[0] / 8;
		if (i < 1)
			i = 1;
		if (i > 31)
			i = 31;

		/* z is not symetric */
		j = (-ent->mins[2]) / 8;
		if (j < 1)
			j = 1;
		if (j > 31)
			j = 31;

		/* and z maxs can be negative... */
		k = (ent->maxs[2] + 32) / 8;
		if (k < 1)
			k = 1;
		if (k > 63)
			k = 63;

		ent->s.solid = (k << 10) | (j << 5) | i;
	} else if (ent->solid == SOLID_BSP) {
		ent->s.solid = 31;	/* a solid_bbox will never create
					 * this value */
	} else
		ent->s.solid = 0;

	/* set the abs box */
	if (ent->solid == SOLID_BSP &&
	    (ent->s.angles[0] || ent->s.angles[1] || ent->s.angles[2])) {	/* expand for rotation */
		float		max     , v;

		max = 0;
		for (i = 0; i < 3; i++) {
			v = fabs(ent->mins[i]);
			if (v > max)
				max = v;
			v = fabs(ent->maxs[i]);
			if (v > max)
				max = v;
		}
		for (i = 0; i < 3; i++) {
			ent->absmin[i] = ent->s.origin[i] - max;
			ent->absmax[i] = ent->s.origin[i] + max;
		}
	} else {		/* normal */
		VectorAdd(ent->s.origin, ent->mins, ent->absmin);
		VectorAdd(ent->s.origin, ent->maxs, ent->absmax);
	}

	/* because movement is clipped an epsilon away from an actual edge, */
	/* we must fully check even when bounding boxes don't quite touch */
	ent->absmin[0] -= 1;
	ent->absmin[1] -= 1;
	ent->absmin[2] -= 1;
	ent->absmax[0] += 1;
	ent->absmax[1] += 1;
	ent->absmax[2] += 1;

	/* link to PVS leafs */
	ent->num_clusters = 0;
	ent->areanum = 0;
	ent->areanum2 = 0;

	/* get all leafs, including solids */
	num_leafs = CM_BoxLeafnums(ent->absmin, ent->absmax,
	    leafs, MAX_TOTAL_ENT_LEAFS, &topnode);

	/* set areas */
	for (i = 0; i < num_leafs; i++) {
		clusters[i] = CM_LeafCluster(leafs[i]);
		area = CM_LeafArea(leafs[i]);
		if (area) {	/* doors may legally straggle two areas, */
			/* but nothing should evern need more than that */
			if (ent->areanum && ent->areanum != area) {
				if (ent->areanum2 && ent->areanum2 != area && sv.state == ss_loading)
					Com_DPrintf("Object touching 3 areas at %f %f %f\n",
					    ent->absmin[0], ent->absmin[1], ent->absmin[2]);
				ent->areanum2 = area;
			} else
				ent->areanum = area;
		}
	}

	if (num_leafs >= MAX_TOTAL_ENT_LEAFS) {	/* assume we missed some
						 * leafs, and mark by
						 * headnode */
		ent->num_clusters = -1;
		ent->headnode = topnode;
	} else {
		ent->num_clusters = 0;
		for (i = 0; i < num_leafs; i++) {
			if (clusters[i] == -1)
				continue;	/* not a visible leaf */
			for (j = 0; j < i; j++)
				if (clusters[j] == clusters[i])
					break;
			if (j == i) {
				if (ent->num_clusters == MAX_ENT_CLUSTERS) {	/* assume we missed some
										 * leafs, and mark by
										 * headnode */
					ent->num_clusters = -1;
					ent->headnode = topnode;
					break;
				}
				ent->clusternums[ent->num_clusters++] = clusters[i];
			}
		}
	}

	/* if first time, make sure old_origin is valid */
	if (!ent->linkcount) {
		VectorCopy(ent->s.origin, ent->s.old_origin);
	}
	ent->linkcount++;

	if (ent->solid == SOLID_NOT)
		return;

	/* find the first node that the ent's box crosses */
	node = sv_areanodes;
	while (1) {
		if (node->axis == -1)
			break;
		if (ent->absmin[node->axis] > node->dist)
			node = node->children[0];
		else if (ent->absmax[node->axis] < node->dist)
			node = node->children[1];
		else
			break;	/* crosses the node */
	}

	/* link it in	 */
	if (ent->solid == SOLID_TRIGGER)
		InsertLinkBefore(&ent->area, &node->trigger_edicts);
	else
		InsertLinkBefore(&ent->area, &node->solid_edicts);

}


/*
 * ==================== SV_AreaEdicts_r
 *
 * ====================
 */
void
SV_AreaEdicts_r(areanode_t * node)
{
	link_t         *l, *next, *start;
	edict_t        *check;
	int		count;

	count = 0;

	/* touch linked edicts */
	if (area_type == AREA_SOLID)
		start = &node->solid_edicts;
	else
		start = &node->trigger_edicts;

	for (l = start->next; l != start; l = next) {
		next = l->next;
		check = EDICT_FROM_AREA(l);

		if (check->solid == SOLID_NOT)
			continue;	/* deactivated */
		if (check->absmin[0] > area_maxs[0]
		    || check->absmin[1] > area_maxs[1]
		    || check->absmin[2] > area_maxs[2]
		    || check->absmax[0] < area_mins[0]
		    || check->absmax[1] < area_mins[1]
		    || check->absmax[2] < area_mins[2])
			continue;	/* not touching */

		if (area_count == area_maxcount) {
			Com_Printf("SV_AreaEdicts: MAXCOUNT\n");
			return;
		}
		area_list[area_count] = check;
		area_count++;
	}

	if (node->axis == -1)
		return;		/* terminal node */

	/* recurse down both sides */
	if (area_maxs[node->axis] > node->dist)
		SV_AreaEdicts_r(node->children[0]);
	if (area_mins[node->axis] < node->dist)
		SV_AreaEdicts_r(node->children[1]);
}

/*
 * ================ SV_AreaEdicts ================
 */
int
SV_AreaEdicts(vec3_t mins, vec3_t maxs, edict_t ** list,
    int maxcount, int areatype)
{
	area_mins = mins;
	area_maxs = maxs;
	area_list = list;
	area_count = 0;
	area_maxcount = maxcount;
	area_type = areatype;

	SV_AreaEdicts_r(sv_areanodes);

	return area_count;
}


/*
 * ===========================================================================
 *
 */

/*
 * ============= SV_PointContents =============
 */
int
SV_PointContents(vec3_t p)
{
	edict_t        *touch[MAX_EDICTS], *hit;
	int		i, num;
	int		contents, c2;
	int		headnode;
	float          *angles;

	/* get base contents from world */
	contents = CM_PointContents(p, sv.models[1]->headnode);

	/* or in contents from all the other entities */
	num = SV_AreaEdicts(p, p, touch, MAX_EDICTS, AREA_SOLID);

	for (i = 0; i < num; i++) {
		hit = touch[i];

		/* might intersect, so do an exact clip */
		headnode = SV_HullForEntity(hit);
		angles = hit->s.angles;
		if (hit->solid != SOLID_BSP)
			angles = vec3_origin;	/* boxes don't rotate */

		c2 = CM_TransformedPointContents(p, headnode, hit->s.origin, hit->s.angles);

		contents |= c2;
	}

	return contents;
}



typedef struct {
	vec3_t		boxmins, boxmaxs;	/* enclose the test object along entire move */
	float          *mins, *maxs;		/* size of the moving object */
	vec3_t		mins2, maxs2;		/* size when clipping against monsters */
	float          *start, *end;
	trace_t		trace;
	edict_t        *passedict;
	int		contentmask;
} moveclip_t;



/*
 * ================ SV_HullForEntity
 *
 * Returns a headnode that can be used for testing or clipping an object of
 * mins/maxs size. Offset is filled in to contain the adjustment that must be
 * added to the testing object's origin to get a point to use with the
 * returned hull. ================
 */
int
SV_HullForEntity(edict_t * ent)
{
	cmodel_t       *model;

	/* decide which clipping hull to use, based on the size */
	if (ent->solid == SOLID_BSP) {	/* explicit hulls in the BSP model */
		model = sv.models[ent->s.modelindex];

		if (!model)
			Com_Error(ERR_FATAL, "MOVETYPE_PUSH with a non bsp model");

		return model->headnode;
	}
	/* create a temp hull from bounding box sizes */

	return CM_HeadnodeForBox(ent->mins, ent->maxs);
}


/*
 * ===========================================================================
 *
 */

/*
 * ==================== SV_ClipMoveToEntities
 *
 * ====================
 */
void
SV_ClipMoveToEntities(moveclip_t * clip)
{
	int		i, num;
	edict_t        *touchlist[MAX_EDICTS], *touch;
	trace_t		trace;
	int		headnode;
	float          *angles;

	num = SV_AreaEdicts(clip->boxmins, clip->boxmaxs, touchlist
	    ,MAX_EDICTS, AREA_SOLID);

	/* be careful, it is possible to have an entity in this */
	/* list removed before we get to it (killtriggered) */
	for (i = 0; i < num; i++) {
		touch = touchlist[i];
		if (touch->solid == SOLID_NOT)
			continue;
		if (touch == clip->passedict)
			continue;
		if (clip->trace.allsolid)
			return;
		if (clip->passedict) {
			if (touch->owner == clip->passedict)
				continue;	/* don't clip against own
						 * missiles */
			if (clip->passedict->owner == touch)
				continue;	/* don't clip against owner */
		}
		if (!(clip->contentmask & CONTENTS_DEADMONSTER)
		    && (touch->svflags & SVF_DEADMONSTER))
			continue;

		/* might intersect, so do an exact clip */
		headnode = SV_HullForEntity(touch);
		angles = touch->s.angles;
		if (touch->solid != SOLID_BSP)
			angles = vec3_origin;	/* boxes don't rotate */

		if (touch->svflags & SVF_MONSTER)
			trace = CM_TransformedBoxTrace(clip->start, clip->end,
			    clip->mins2, clip->maxs2, headnode, clip->contentmask,
			    touch->s.origin, angles);
		else
			trace = CM_TransformedBoxTrace(clip->start, clip->end,
			    clip->mins, clip->maxs, headnode, clip->contentmask,
			    touch->s.origin, angles);

		if (trace.allsolid || trace.startsolid ||
		    trace.fraction < clip->trace.fraction) {
			trace.ent = touch;
			if (clip->trace.startsolid) {
				clip->trace = trace;
				clip->trace.startsolid = true;
			} else
				clip->trace = trace;
		} else if (trace.startsolid)
			clip->trace.startsolid = true;
	}
}


/*
 * ================== SV_TraceBounds ==================
 */
void
SV_TraceBounds(vec3_t start, vec3_t mins, vec3_t maxs, vec3_t end, vec3_t boxmins, vec3_t boxmaxs)
{
	int		i;

	for (i = 0; i < 3; i++) {
		if (end[i] > start[i]) {
			boxmins[i] = start[i] + mins[i] - 1;
			boxmaxs[i] = end[i] + maxs[i] + 1;
		} else {
			boxmins[i] = end[i] + mins[i] - 1;
			boxmaxs[i] = start[i] + maxs[i] + 1;
		}
	}
}

/*
 * ================== SV_Trace
 *
 * Moves the given mins/maxs volume through the world from start to end.
 *
 * Passedict and edicts owned by passedict are explicitly not checked.
 *
 * ==================
 */
trace_t
SV_Trace(vec3_t start, vec3_t mins, vec3_t maxs, vec3_t end, edict_t * passedict, int contentmask)
{
	moveclip_t	clip;

	if (!mins)
		mins = vec3_origin;
	if (!maxs)
		maxs = vec3_origin;

	memset(&clip, 0, sizeof(moveclip_t));

	/* clip to world */
	clip.trace = CM_BoxTrace(start, end, mins, maxs, 0, contentmask);
	clip.trace.ent = ge->edicts;
	if (clip.trace.fraction == 0)
		return clip.trace;	/* blocked by the world */

	clip.contentmask = contentmask;
	clip.start = start;
	clip.end = end;
	clip.mins = mins;
	clip.maxs = maxs;
	clip.passedict = passedict;

	VectorCopy(mins, clip.mins2);
	VectorCopy(maxs, clip.maxs2);

	/* create the bounding box of the entire move */
	SV_TraceBounds(start, clip.mins2, clip.maxs2, end, clip.boxmins, clip.boxmaxs);

	/* clip to other solid entities */
	SV_ClipMoveToEntities(&clip);

	return clip.trace;
}