/*
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.

*/

#include "cg_local.h"

int cg_numSolids;
entity_state_t *cg_solidList[MAX_PARSE_ENTITIES];

/*
===================
CG_CheckPredictionError
===================
*/
void CG_CheckPredictionError( void )
{
	int		frame;
	int		delta[3];

	if( !cg_predict->integer || cg.demoPlaying ||
		(cg.frame.playerState.pmove.pm_flags & PMF_NO_PREDICTION) )
		return;

	trap_NET_GetCurrentState( &frame, NULL );

	// calculate the last usercmd_t we sent that the server has processed
	frame = frame & CMD_MASK;

	// compare what the server returned with what we had predicted it to be
	VectorSubtract( cg.frame.playerState.pmove.origin, cg.predictedOrigins[frame], delta );

	// save the prediction error for interpolation
	if( abs(delta[0]) > 128*16 || abs(delta[1]) > 128*16 || abs(delta[2]) > 128*16 ) {
		VectorClear( cg.predictionError );					// a teleport or something
	} else {
		if( cg_showMiss->integer && (delta[0] || delta[1] || delta[2]) )
			CG_Printf( "prediction miss on %i: %i\n", cg.frame.serverFrame, delta[0] + delta[1] + delta[2] );
		VectorCopy( cg.frame.playerState.pmove.origin, cg.predictedOrigins[frame] );
		VectorScale( delta, (1.0/16.0), cg.predictionError );	// save for error interpolation
	}
}

/*
====================
CG_BuildSolidList
====================
*/
void CG_BuildSolidList( void )
{
	int	i;

	entity_state_t *ent;

	cg_numSolids = 0;
	for( i = 0; i < cg.frame.numEntities; i++ ) {
		ent = &cg.frame.parsedEntities[i & (MAX_PARSE_ENTITIES-1)];
		if( ent->solid )
			cg_solidList[cg_numSolids++] = ent;
	}
}

/*
====================
CG_ClipMoveToEntities
====================
*/
void CG_ClipMoveToEntities( vec3_t start, vec3_t mins, vec3_t maxs, vec3_t end, int ignore, int contentmask, trace_t *tr )
{
#define INTERPOLATEBOXES
	int			i, x, zd, zu;
	trace_t		trace;
	vec3_t		origin, angles;
	entity_state_t	*ent;
	struct cmodel_s	*cmodel;
	vec3_t		bmins, bmaxs;

	for( i = 0; i < cg_numSolids; i++ ) {
		ent = cg_solidList[i];

		if( ent->number == ignore )
			continue;
		if( !(contentmask & CONTENTS_CORPSE) && (ent->effects & EF_CORPSE) )
			continue;

		if ( ent->solid == SOLID_BMODEL ) {	// special value for bmodel
			cmodel = trap_CM_InlineModel( ent->modelindex );
			if( !cmodel )
				continue;
#ifdef INTERPOLATEBOXES
			{
				int j;
				centity_t *cent = &cg_entities[ent->number];
				VectorCopy( cent->ent.origin, origin );
				for( j = 0; j < 3; j++ )
					angles[j] = LerpAngle(cent->prev.angles[j], cent->current.angles[j], cg.lerpfrac );
			}
#else
			VectorCopy( ent->origin, origin );
			VectorCopy( ent->angles, angles );
#endif
		} else {							// encoded bbox
			x = 8 * (ent->solid & 31);
			zd = 8 * ((ent->solid>>5) & 31);
			zu = 8 * ((ent->solid>>10) & 63) - 32;

			bmins[0] = bmins[1] = -x;
			bmaxs[0] = bmaxs[1] = x;
			bmins[2] = -zd;
			bmaxs[2] = zu;
#ifdef INTERPOLATEBOXES
			VectorCopy( cg_entities[ent->number].ent.origin, origin );
			VectorClear( angles );	// boxes don't rotate
#else
			VectorCopy( ent->origin, origin );
			VectorClear( angles );	// boxes don't rotate
#endif
			cmodel = trap_CM_ModelForBBox( bmins, bmaxs );
		}

		trap_CM_TransformedBoxTrace( &trace, start, end, mins, maxs, cmodel, contentmask, origin, angles );
		if( trace.allsolid || trace.fraction < tr->fraction ) {
			trace.ent = ent->number;
			*tr = trace;
		} else if( trace.startsolid ) {
			tr->startsolid = qtrue;
		}
		if( tr->allsolid )
			return;
	}
}


/*
================
CG_Trace
================
*/
void CG_Trace( trace_t *t, vec3_t start, vec3_t mins, vec3_t maxs, vec3_t end, int ignore, int contentmask )
{
	// check against world
	trap_CM_BoxTrace( t, start, end, mins, maxs, NULL, contentmask );
	t->ent = 0;
	if( t->fraction == 0 )
		return;			// blocked by the world

	// check all other solid models
	CG_ClipMoveToEntities( start, mins, maxs, end, ignore, contentmask, t );
}


/*
================
CG_PMTrace
================
*/
void CG_PMTrace( trace_t *tr, vec3_t start, vec3_t mins, vec3_t maxs, vec3_t end ) 
{
	// wsw: pb disable player collision in race mode (thanks Medar)
	if( cg.frame.playerState.stats[STAT_GAMETYPE] == GAMETYPE_RACE )
		CG_Trace( tr, start, mins, maxs, end, cgs.playerNum+1, MASK_DEADSOLID );
	else
		CG_Trace( tr, start, mins, maxs, end, cgs.playerNum+1, MASK_PLAYERSOLID );
}

/*
================
CG_PointContents
================
*/
int	CG_PointContents( vec3_t point )
{
	int			i;
	entity_state_t	*ent;
	struct cmodel_s	*cmodel;
	int			contents;

	contents = trap_CM_PointContents( point, NULL );

	for( i = 0; i < cg_numSolids; i++ ) {
		ent = cg_solidList[i];
		if( ent->solid != SOLID_BMODEL )	// special value for bmodel
			continue;

		cmodel = trap_CM_InlineModel( ent->modelindex );
		if( cmodel )
			contents |= trap_CM_TransformedPointContents ( point, cmodel, ent->origin, ent->angles );
	}

	return contents;
}


int				predictedSteps[CMD_BACKUP];	// for step smoothing
/*
=================
CG_PredictAddStep
=================
*/
void CG_PredictAddStep( int virtualtime, int predictiontime, int stepSize ) {
	
	float	oldStep;
	int		delta;
	int		step;

	// check for stepping up before a previous step is completed
	delta = cg.realTime - cg.predictedStepTime;
	if (delta < PREDICTED_STEP_TIME) {
		oldStep = cg.predictedStep * ((float)(PREDICTED_STEP_TIME - delta) / (float)PREDICTED_STEP_TIME);
	} else {
		oldStep = 0;
	}

	step = stepSize + 1;
	cg.predictedStep = oldStep + step;
	cg.predictedStepTime = cg.realTime - ( predictiontime - virtualtime );
}

/*
=================
CG_PredictSmoothSteps
=================
*/
void CG_PredictSmoothSteps( void ) {
	int			outgoing;
	int			frame;
	usercmd_t	cmd;
	int			i;
	int			virtualtime = 0, predictiontime = 0;

	cg.predictedStepTime = 0;
	cg.predictedStep = 0;
	
	trap_NET_GetCurrentState( NULL, &outgoing );

	i = outgoing;
	while( predictiontime < PREDICTED_STEP_TIME )
	{
		if( outgoing - i >= CMD_BACKUP )
			break;
		
		frame = i & CMD_MASK;
		trap_NET_GetUserCmd( frame, &cmd );
		predictiontime += cmd.msec;
		i--;
	}

	// run frames
	while( ++i <= outgoing ) {
		frame = i & CMD_MASK;
		trap_NET_GetUserCmd( frame, &cmd );
		virtualtime += cmd.msec;

		if( predictedSteps[frame] ) {
			CG_PredictAddStep( virtualtime, predictiontime, predictedSteps[frame] );
		}
	}
}

/*
=================
CG_PredictMovement

Sets cg.predictedVelocty, cg.predictedOrigin and cg.predictedAngles
=================
*/
void CG_PredictMovement( void )
{
	int			ack, outgoing;
	int			frame;
	usercmd_t	cmd;
	pmove_t		pm;
	int			i;

	if( !cg_predict->integer || cg.demoPlaying ||
		(cg.frame.playerState.pmove.pm_flags & PMF_NO_PREDICTION) ) {
		// just set angles
		trap_NET_GetUserCmd( trap_NET_GetCurrentUserCmdNum(), &cmd ); // the command being built but yet unsent

		VectorScale( cg.frame.playerState.pmove.velocity, (1.0/16.0), cg.predictedVelocity );
		VectorScale( cg.frame.playerState.pmove.origin, (1.0/16.0), cg.predictedOrigin );

		for( i = 0; i < 3; i++ )
			cg.predictedAngles[i] = SHORT2ANGLE( cmd.angles[i] ) + SHORT2ANGLE( cg.frame.playerState.pmove.delta_angles[i] );
		return;
	}

	trap_NET_GetCurrentState( &ack, &outgoing );

	// if we are too far out of date, just freeze
	if( outgoing - ack >= CMD_BACKUP ) {
		if( cg_showMiss->integer )
			CG_Printf( "exceeded CMD_BACKUP\n" );
		return;	
	}
	
	// copy current state to pmove
	memset( &pm, 0, sizeof(pm) );
	pm.trace = CG_PMTrace;
	pm.pointcontents = CG_PointContents;
	pm.s = cg.frame.playerState.pmove;
	if( cg.demoPlaying )
		pm.s.pm_type = PM_FREEZE;

	// wsw : jal : set max_walljump count for gametype
	pm.max_walljumps = GS_GameType_MaxWallJumps( cg.frame.playerState.stats[STAT_GAMETYPE] );

	// run frames
	while( ++ack <= outgoing ) {
		frame = ack & CMD_MASK;
		trap_NET_GetUserCmd( frame, &pm.cmd );
		Pmove( &pm );

		//copy for stair smoothing
		predictedSteps[frame] = pm.step;

		// save for debug checking
		VectorCopy( pm.s.origin, cg.predictedOrigins[frame] ); // jal : does this still have any use?
	}

	// copy results out for rendering
	cg.groundEntity = pm.groundentity;
	VectorScale( pm.s.velocity, (1.0/16.0), cg.predictedVelocity );
	VectorScale( pm.s.origin, (1.0/16.0), cg.predictedOrigin );
	VectorCopy( pm.viewangles, cg.predictedAngles );

	CG_PredictSmoothSteps();
}