/*
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.

*/
#include "quakedef.h"
#include "winquake.h"

cvar_t	cl_nopred = {"cl_nopred","0"};
cvar_t	cl_pushlatency = {"pushlatency","-999"};

extern	frame_t		*view_frame;

/*
=================
CL_NudgePosition

If pmove.origin is in a solid position,
try nudging slightly on all axis to
allow for the cut precision of the net coordinates
=================
*/
void CL_NudgePosition (void)
{
	vec3_t	base;
	int		x, y;

	if (PM_HullPointContents (&cl.model_precache[1]->hulls[1], 0, pmove.origin) == CONTENTS_EMPTY)
		return;

	VectorCopy (pmove.origin, base);
	for (x=-1 ; x<=1 ; x++)
	{
		for (y=-1 ; y<=1 ; y++)
		{
			pmove.origin[0] = base[0] + x * 1.0/8;
			pmove.origin[1] = base[1] + y * 1.0/8;
			if (PM_HullPointContents (&cl.model_precache[1]->hulls[1], 0, pmove.origin) == CONTENTS_EMPTY)
				return;
		}
	}
	Con_DPrintf ("CL_NudgePosition: stuck\n");
}

/*
==============
CL_PredictUsercmd
==============
*/
void CL_PredictUsercmd (player_state_t *from, player_state_t *to, usercmd_t *u, qboolean spectator)
{
	// split up very long moves
	if (u->msec > 50)
	{
		player_state_t	temp;
		usercmd_t	split;

		split = *u;
		split.msec /= 2;

		CL_PredictUsercmd (from, &temp, &split, spectator);
		CL_PredictUsercmd (&temp, to, &split, spectator);
		return;
	}

	VectorCopy (from->origin, pmove.origin);
//	VectorCopy (from->viewangles, pmove.angles);
	VectorCopy (u->angles, pmove.angles);
	VectorCopy (from->velocity, pmove.velocity);

	pmove.oldbuttons = from->oldbuttons;
	pmove.waterjumptime = from->waterjumptime;
	pmove.dead = cl.stats[STAT_HEALTH] <= 0;
	pmove.spectator = spectator;

	pmove.cmd = *u;

	PlayerMove ();
//for (i=0 ; i<3 ; i++)
//pmove.origin[i] = ((int)(pmove.origin[i]*8))*0.125;
	to->waterjumptime = pmove.waterjumptime;
	to->oldbuttons = pmove.cmd.buttons;
	VectorCopy (pmove.origin, to->origin);
	VectorCopy (pmove.angles, to->viewangles);
	VectorCopy (pmove.velocity, to->velocity);
	to->onground = onground;

	to->weaponframe = from->weaponframe;
}



/*
==============
CL_PredictMove
==============
*/
void CL_PredictMove (void)
{
	int			i;
	float		f;
	frame_t		*from, *to = NULL;
	int			oldphysent;

	if (cl_pushlatency.value > 0)
		Cvar_Set ("pushlatency", "0");

	if (cl.paused)
		return;

	cl.time = realtime - cls.latency - cl_pushlatency.value*0.001;
	if (cl.time > realtime)
		cl.time = realtime;

	if (cl.intermission)
		return;

	if (!cl.validsequence)
		return;

	if (cls.netchan.outgoing_sequence - cls.netchan.incoming_sequence >= UPDATE_BACKUP-1)
		return;

	VectorCopy (cl.viewangles, cl.simangles);

	// this is the last frame received from the server
	from = &cl.frames[cls.netchan.incoming_sequence & UPDATE_MASK];

	// we can now render a frame
	if (cls.state == ca_onserver)
	{	// first update is the final signon stage
		char		text[1024];

		cls.state = ca_active;
		sprintf (text, "QuakeWorld: %s", cls.servername);
#ifdef _WIN32
		SetWindowText (mainwindow, text);
#endif
	}

	if (cl_nopred.value)
	{
		VectorCopy (from->playerstate[cl.playernum].velocity, cl.simvel);
		VectorCopy (from->playerstate[cl.playernum].origin, cl.simorg);
		return;
	}

	// predict forward until cl.time <= to->senttime
	oldphysent = pmove.numphysent;
	CL_SetSolidPlayers (cl.playernum);

//	to = &cl.frames[cls.netchan.incoming_sequence & UPDATE_MASK];

	for (i=1 ; i<UPDATE_BACKUP-1 && cls.netchan.incoming_sequence+i <
			cls.netchan.outgoing_sequence; i++)
	{
		to = &cl.frames[(cls.netchan.incoming_sequence+i) & UPDATE_MASK];
		CL_PredictUsercmd (&from->playerstate[cl.playernum]
			, &to->playerstate[cl.playernum], &to->cmd, cl.spectator);
		if (to->senttime >= cl.time)
			break;
		from = to;
	}

	pmove.numphysent = oldphysent;

	if (i == UPDATE_BACKUP-1 || !to)
		return;		// net hasn't deliver packets in a long time...

	// now interpolate some fraction of the final frame
	if (to->senttime == from->senttime)
		f = 0;
	else
	{
		f = (cl.time - from->senttime) / (to->senttime - from->senttime);

		if (f < 0)
			f = 0;
		if (f > 1)
			f = 1;
	}

	for (i=0 ; i<3 ; i++)
		if ( fabs(from->playerstate[cl.playernum].origin[i] - to->playerstate[cl.playernum].origin[i]) > 128)
		{	// teleported, so don't lerp
			VectorCopy (to->playerstate[cl.playernum].velocity, cl.simvel);
			VectorCopy (to->playerstate[cl.playernum].origin, cl.simorg);
			return;
		}
		
	for (i=0 ; i<3 ; i++)
	{
		cl.simorg[i] = from->playerstate[cl.playernum].origin[i] 
			+ f*(to->playerstate[cl.playernum].origin[i] - from->playerstate[cl.playernum].origin[i]);
		cl.simvel[i] = from->playerstate[cl.playernum].velocity[i] 
			+ f*(to->playerstate[cl.playernum].velocity[i] - from->playerstate[cl.playernum].velocity[i]);
	}		
}


/*
==============
CL_InitPrediction
==============
*/
void CL_InitPrediction (void)
{
	Cvar_RegisterVariable (&cl_pushlatency);
	Cvar_RegisterVariable (&cl_nopred);
}