/*
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 "sv_local.h"

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

ENTITY AREA CHECKING

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

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

#define	AREA_DEPTH	4
#define	AREA_NODES	32

static areanode_t	sv_areanodes[AREA_NODES];
static int			sv_numareanodes;

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

/*
===============
SV_CreateAreaNode

Builds a uniformly subdivided tree for the given world size
===============
*/
static 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++;

	List_Init (&anode->trigger_edicts);
	List_Init (&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 ) {
	mmodel_t *cm;
	edict_t *ent;
	int i;

	memset( sv_areanodes, 0, sizeof( sv_areanodes ) );
	sv_numareanodes = 0;

	if( sv.cm.cache ) {
		cm = &sv.cm.cache->models[0];
		SV_CreateAreaNode( 0, cm->mins, cm->maxs );
	}

	// make sure all entities are unlinked
	for( i = 0; i < MAX_EDICTS; i++ ) {
		ent = EDICT_NUM( i );
		ent->area.prev = ent->area.next = NULL;
	}
}


/*
===============
SV_LinkEdict

General purpose routine shared by game DLL and MVD code.
Links entity to PVS leafs.
===============
*/
void SV_LinkEdict( cm_t *cm, edict_t *ent ) {
	mleaf_t		*leafs[MAX_TOTAL_ENT_LEAFS];
	int			clusters[MAX_TOTAL_ENT_LEAFS];
	int			num_leafs;
	int			i, j;
	int			area;
	mnode_t		*topnode;

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

	// 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;
		int			i;

		max = 0;
		for (i=0 ; i<3 ; i++) {
			v = Q_fabs( ent->mins[i]);
			if (v > max)
				max = v;
			v = Q_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_BoxLeafs( cm, 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 = CM_NumNode( cm, 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 = CM_NumNode( cm, topnode );
					break;
				}

				ent->clusternums[ent->num_clusters++] = clusters[i];
			}
		}
	}
}

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

static int SV_CalcSolid( vec3_t mins, vec3_t maxs ) {
	int	i, j, k;

    // assume that x/y are equal and symetric
    i = maxs[0] / 8;
    clamp( i, 1, 31 );

    // z is not symetric
    j = ( -mins[2] ) / 8;
    clamp( j, 1, 31 );

    // and z maxs can be negative...
    k = ( maxs[2] + 32 ) / 8;
    clamp( k, 1, 63 );

    return ( k << 10 ) | ( j << 5 ) | i;
}

static int SV_CalcSolid32( vec3_t mins, vec3_t maxs ) {
	int	i, j, k;

    // assume that x/y are equal and symetric
    i = maxs[0];
    clamp( i, 1, 255 );

    // z is not symetric
    j = -mins[2];
    clamp( j, 1, 255 );

    // and z maxs can be negative...
    k = maxs[2] + 32768;
    clamp( k, 1, 65535 );

    return ( k << 16 ) | ( j << 8 ) | i;
}

void PF_LinkEdict (edict_t *ent) {
	areanode_t	*node;
    server_entity_t *sent;
    int entnum;

	if (ent->area.prev)
		PF_UnlinkEdict (ent);	// unlink from old position
		
	if (ent == ge->edicts)
		return;		// don't add the world

	if (!ent->inuse)
		return;

	if( !sv.cm.cache ) {
		return;
	}

    entnum = NUM_FOR_EDICT( ent );
    sent = &sv.entities[entnum];

	// encode the size into the entity_state for client prediction
	switch( ent->solid ) {
    case SOLID_BBOX:
        if( ( ent->svflags & SVF_DEADMONSTER ) || VectorCompare( ent->mins, ent->maxs ) ) {
            ent->s.solid = 0;
            sent->solid32 = 0;
        } else {
            ent->s.solid = SV_CalcSolid( ent->mins, ent->maxs );
            sent->solid32 = SV_CalcSolid32( ent->mins, ent->maxs );
        }
        break;
    case SOLID_BSP:
		ent->s.solid = 31;		// a solid_bbox will never create this value
        sent->solid32 = 31;     // FIXME: use 255?
        break;
    default:
		ent->s.solid = 0;
        sent->solid32 = 0;
        break;
    }

    SV_LinkEdict( &sv.cm, ent );

	// 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)
        List_Append( &node->trigger_edicts, &ent->area );
	else
        List_Append( &node->solid_edicts, &ent->area );
}


/*
====================
SV_AreaEdicts_r

====================
*/
static void SV_AreaEdicts_r (areanode_t *node) {
	list_t		*start;
	edict_t		*check;

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

    LIST_FOR_EACH( edict_t, check, start, area ) {
		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_WPrintf ("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_HullForEntity

Returns a headnode that can be used for testing or clipping an
object of mins/maxs size.
================
*/
static mnode_t *SV_HullForEntity( edict_t *ent ) {
	mmodel_t	*model;

	if( ent->solid == SOLID_BSP ) {
		// explicit hulls in the BSP model
		if( ent->s.modelindex < 2 || ent->s.modelindex > sv.cm.cache->nummodels ) {
			Com_Error( ERR_DROP, "%s: inline model index %d out of range",
                __func__, ent->s.modelindex );
		}

		model = &sv.cm.cache->models[ ent->s.modelindex - 1 ];

		return model->headnode;
	}

	// create a temp hull from bounding box sizes
	return CM_HeadnodeForBox( ent->mins, ent->maxs );
}

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

	if( !sv.cm.cache ) {
		Com_Error( ERR_DROP, "%s: no map loaded", __func__ );
	}

	// get base contents from world
	contents = CM_PointContents (p, sv.cm.cache->nodes);

	// 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);

		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
	vec_t		*mins, *maxs;	// size of the moving object
	vec_t		*start, *end;
	trace_t		*trace;
	edict_t		*passedict;
	int			contentmask;
} moveclip_t;

/*
====================
SV_ClipMoveToEntities

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

	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);

		CM_TransformedBoxTrace (&trace, clip->start, clip->end,
			clip->mins, clip->maxs, headnode,  clip->contentmask,
			touch->s.origin, touch->s.angles);

		CM_ClipEntity( clip->trace, &trace, touch );
	}
}


/*
==================
SV_TraceBounds
==================
*/
static void SV_TraceBounds (moveclip_t *clip) {
	int		i;
	
	for (i=0 ; i<3 ; i++) {
		if (clip->end[i] > clip->start[i]) {
			clip->boxmins[i] = clip->start[i] + clip->mins[i] - 1;
			clip->boxmaxs[i] = clip->end[i] + clip->maxs[i] + 1;
		} else {
			clip->boxmins[i] = clip->end[i] + clip->mins[i] - 1;
			clip->boxmaxs[i] = clip->start[i] + clip->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(trace_t *trace, vec3_t start, vec3_t mins, vec3_t maxs, vec3_t end,
					   edict_t *passedict, int contentmask)
{
	moveclip_t	clip;

	if( !sv.cm.cache ) {
		Com_Error( ERR_DROP, "%s: no map loaded", __func__ );
	}

	if( ++sv.tracecount > 10000 ) {
		Com_EPrintf( "SV_Trace: game DLL caught in infinite loop!\n" );
		memset( trace, 0, sizeof( *trace ) );
		trace->fraction = 1;
		trace->ent = ge->edicts;
		VectorCopy( end, trace->endpos );
		sv.tracecount = 0;
		return trace;
	}

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

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

	memset( &clip, 0, sizeof( clip ) );
	clip.trace = trace;
	clip.contentmask = contentmask;
	clip.start = start;
	clip.end = end;
	clip.mins = mins;
	clip.maxs = maxs;
	clip.passedict = passedict;
	
	// create the bounding box of the entire move
	SV_TraceBounds( &clip );

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

	return trace;
}

/*
==================
SV_Trace_Native

Variant of SV_Trace for native game ABI
==================
*/
trace_t SV_Trace_Native (vec3_t start, vec3_t mins, vec3_t maxs, vec3_t end, edict_t *passedict, int contentmask) {
	trace_t trace;

    SV_Trace( &trace, start, mins, maxs, end, passedict, contentmask );

	return trace;
}