// I_pcnet.m

#include "DoomDef.h"
#include "P_local.h"
#include "soundst.h"

#define NCMD_EXIT               0x80000000
#define NCMD_RETRANSMIT 0x40000000
#define NCMD_SETUP              0x20000000
#define NCMD_KILL               0x10000000              // kill game
#define NCMD_CHECKSUM   0x0fffffff

 
doomcom_t               *doomcom;       
doomdata_t              *netbuffer;             // points inside doomcom


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

							NETWORKING

gametic is the tic about to (or currently being) run
maketic is the tick that hasn't had control made for it yet
nettics[] has the maketics for all players 

a gametic cannot be run until nettics[] > gametic for all players

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

#define RESENDCOUNT     10
#define PL_DRONE        0x80                            // bit flag in doomdata->player

ticcmd_t                localcmds[BACKUPTICS];

ticcmd_t        netcmds[MAXPLAYERS][BACKUPTICS];
int             nettics[MAXNETNODES];
boolean                 nodeingame[MAXNETNODES];        // set false as nodes leave game
boolean                 remoteresend[MAXNETNODES];      // set when local needs tics
int                             resendto[MAXNETNODES];                  // set when remote needs tics
int                             resendcount[MAXNETNODES];

int                             nodeforplayer[MAXPLAYERS];

int             maketic;
int                             lastnettic, skiptics;
int                             ticdup;         
int                             maxsend;        // BACKUPTICS/(2*ticdup)-1

void D_ProcessEvents (void); 
void G_BuildTiccmd (ticcmd_t *cmd); 
void D_DoAdvanceDemo (void);
 
boolean                 reboundpacket;
doomdata_t              reboundstore;


int     NetbufferSize (void)
{
	return (int)&(((doomdata_t *)0)->cmds[netbuffer->numtics]); 
}

unsigned NetbufferChecksum (void)
{
	unsigned                c;
	int             i,l;

	c = 0x1234567;

#ifdef NeXT
	return 0;                       // byte order problems
#endif

	l = (NetbufferSize () - (int)&(((doomdata_t *)0)->retransmitfrom))/4;
	for (i=0 ; i<l ; i++)
		c += ((unsigned *)&netbuffer->retransmitfrom)[i] * (i+1);

	return c & NCMD_CHECKSUM;
}

int ExpandTics (int low)
{
	int     delta;
	
	delta = low - (maketic&0xff);
	
	if (delta >= -64 && delta <= 64)
		return (maketic&~0xff) + low;
	if (delta > 64)
		return (maketic&~0xff) - 256 + low;
	if (delta < -64)
		return (maketic&~0xff) + 256 + low;
		
	I_Error ("ExpandTics: strange value %i at maketic %i",low,maketic);
	return 0;
}


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


/*
==============
=
= HSendPacket
=
==============
*/

void HSendPacket (int node, int flags)
{
	netbuffer->checksum = NetbufferChecksum () | flags;

	if (!node)
	{
		reboundstore = *netbuffer;
		reboundpacket = true;
		return;
	}

	if (demoplayback)
		return;

	if (!netgame)
		I_Error ("Tried to transmit to another node");
		
	doomcom->command = CMD_SEND;
	doomcom->remotenode = node;
	doomcom->datalength = NetbufferSize ();
	
if (debugfile)
{
	int             i;
	int             realretrans;
	if (netbuffer->checksum & NCMD_RETRANSMIT)
		realretrans = ExpandTics (netbuffer->retransmitfrom);
	else
		realretrans = -1;
	fprintf (debugfile,"send (%i + %i, R %i) [%i] "
	,ExpandTics(netbuffer->starttic),netbuffer->numtics, realretrans, doomcom->datalength);
	for (i=0 ; i<doomcom->datalength ; i++)
		fprintf (debugfile,"%i ",((byte *)netbuffer)[i]);
	fprintf (debugfile,"\n");
}

	I_NetCmd ();
}

/*
==============
=
= HGetPacket
=
= Returns false if no packet is waiting
=
==============
*/

boolean HGetPacket (void)
{       
	if (reboundpacket)
	{
		*netbuffer = reboundstore;
		doomcom->remotenode = 0;
		reboundpacket = false;
		return true;
	}

	if (!netgame)
		return false;
	if (demoplayback)
		return false;
		
	doomcom->command = CMD_GET;
	I_NetCmd ();
	if (doomcom->remotenode == -1)
		return false;

	if (doomcom->datalength != NetbufferSize ())
	{
		if (debugfile)
			fprintf (debugfile,"bad packet length %i\n",doomcom->datalength);
		return false;
	}
	
	if (NetbufferChecksum () != (netbuffer->checksum&NCMD_CHECKSUM) )
	{
		if (debugfile)
			fprintf (debugfile,"bad packet checksum\n");
		return false;
	}

if (debugfile)
{
	int             realretrans;
			int     i;
			
	if (netbuffer->checksum & NCMD_SETUP)
		fprintf (debugfile,"setup packet\n");
	else
	{
		if (netbuffer->checksum & NCMD_RETRANSMIT)
			realretrans = ExpandTics (netbuffer->retransmitfrom);
		else
			realretrans = -1;
		fprintf (debugfile,"get %i = (%i + %i, R %i)[%i] ",doomcom->remotenode,
		ExpandTics(netbuffer->starttic),netbuffer->numtics, realretrans, doomcom->datalength);
		for (i=0 ; i<doomcom->datalength ; i++)
			fprintf (debugfile,"%i ",((byte *)netbuffer)[i]);
		fprintf (debugfile,"\n");
	}
}
	return true;    
}


/*
===================
=
= GetPackets
=
===================
*/

char    exitmsg[80];

void GetPackets (void)
{
	int             netconsole;
	int             netnode;
	ticcmd_t        *src, *dest;
	int             realend;
	int             realstart;
				 
	while (HGetPacket ())
	{
		if (netbuffer->checksum & NCMD_SETUP)
			continue;               // extra setup packet
			
		netconsole = netbuffer->player & ~PL_DRONE;
		netnode = doomcom->remotenode;
		//
		// to save bytes, only the low byte of tic numbers are sent
		// Figure out what the rest of the bytes are
		//
		realstart = ExpandTics (netbuffer->starttic);           
		realend = (realstart+netbuffer->numtics);
		
		//
		// check for exiting the game
		//
		if (netbuffer->checksum & NCMD_EXIT)
		{
			if (!nodeingame[netnode])
				continue;
			nodeingame[netnode] = false;
			playeringame[netconsole] = false;
			strcpy(exitmsg, "PLAYER 1 LEFT THE GAME");
			S_StartSound(NULL, sfx_chat);
			exitmsg[7] += netconsole;
			//players[consoleplayer].message = exitmsg;
			P_SetMessage(&players[consoleplayer], exitmsg, true);
/*                      if (demorecording)
				G_CheckDemoStatus ();
*/ // DEBUG
			continue;
		}

		//
		// check for a remote game kill
		//
		if (netbuffer->checksum & NCMD_KILL)
			I_Error ("Killed by network driver");

		nodeforplayer[netconsole] = netnode;
		
		//
		// check for retransmit request
		//
		if ( resendcount[netnode] <= 0 
		&& (netbuffer->checksum & NCMD_RETRANSMIT) )
		{
			resendto[netnode] = ExpandTics(netbuffer->retransmitfrom);
if (debugfile)
fprintf (debugfile,"retransmit from %i\n", resendto[netnode]);
			resendcount[netnode] = RESENDCOUNT;
		}
		else
			resendcount[netnode]--;

		//
		// check for out of order / duplicated packet
		//              
		if (realend == nettics[netnode])
			continue;
			
		if (realend < nettics[netnode])
		{
if (debugfile)
fprintf (debugfile,"out of order packet (%i + %i)\n" ,realstart,netbuffer->numtics);
			continue;
		}

		//
		// check for a missed packet
		//
		if (realstart > nettics[netnode])
		{
		// stop processing until the other system resends the missed tics
if (debugfile)
fprintf (debugfile,"missed tics from %i (%i - %i)\n", netnode, realstart, nettics[netnode]);
			remoteresend[netnode] = true;
			continue;
		}
	
//
// update command store from the packet
//
{
	int             start;

		remoteresend[netnode] = false;
		
		start = nettics[netnode] - realstart;           
		src = &netbuffer->cmds[start];

		while (nettics[netnode] < realend)
		{
			dest = &netcmds[netconsole][nettics[netnode]%BACKUPTICS];
			nettics[netnode]++;
			*dest = *src;
			src++;
		}
	}
}

}

/*
=============
=
= NetUpdate
=
= Builds ticcmds for console player
= sends out a packet
=============
*/

int      gametime;

void NetUpdate (void)
{
	int             nowtime;
	int             newtics;
	int                             i,j;
	int                             realstart;
	int                             gameticdiv;
			
//
// check time
//  
	nowtime = I_GetTime ()/ticdup;
	newtics = nowtime - gametime;
	gametime = nowtime;
	
	if (newtics <= 0)                       // nothing new to update
		goto listen; 

	if (skiptics <= newtics)
	{
		newtics -= skiptics;
		skiptics = 0;
	}
	else
	{
		skiptics -= newtics;
		newtics = 0;
	}
	
		
	netbuffer->player = consoleplayer;
		
//
// build new ticcmds for console player
//
	gameticdiv = gametic/ticdup;
	for (i=0 ; i<newtics ; i++)
	{
		I_StartTic ();
		D_ProcessEvents ();
		if (maketic - gameticdiv >= BACKUPTICS/2-1)
			break;          // can't hold any more
//printf ("mk:%i ",maketic);
		G_BuildTiccmd (&localcmds[maketic%BACKUPTICS]);
		maketic++;
	}


	if (singletics)
		return;         // singletic update is syncronous
		
//
// send the packet to the other nodes
//
	for (i=0 ; i<doomcom->numnodes ; i++)
		if (nodeingame[i])
		{
			netbuffer->starttic = realstart = resendto[i];
			netbuffer->numtics = maketic - realstart;
			if (netbuffer->numtics > BACKUPTICS)
				I_Error ("NetUpdate: netbuffer->numtics > BACKUPTICS");

			resendto[i] = maketic - doomcom->extratics;
	

			for (j=0 ; j< netbuffer->numtics ; j++)
				netbuffer->cmds[j] = 
					localcmds[(realstart+j)%BACKUPTICS];
					
			if (remoteresend[i])
			{
				netbuffer->retransmitfrom = nettics[i];
				HSendPacket (i, NCMD_RETRANSMIT);
			}
			else
			{
				netbuffer->retransmitfrom = 0;
				HSendPacket (i, 0);
			}
		}

//
// listen for other packets
//              
listen:

	GetPackets ();
}


/*
=====================
=
= CheckAbort
=
=====================
*/

void CheckAbort (void)
{
	event_t *ev;
	int             stoptic;
	
	stoptic = I_GetTime () + 2; 
	while (I_GetTime() < stoptic) 
		I_StartTic (); 
	
	I_StartTic ();
	for ( ; eventtail != eventhead 
	; eventtail = (++eventtail)&(MAXEVENTS-1) ) 
	{ 
		ev = &events[eventtail]; 
		if (ev->type == ev_keydown && ev->data1 == KEY_ESCAPE)
			I_Error ("Network game synchronization aborted.");
	} 
}

/*
=====================
=
= D_ArbitrateNetStart
=
=====================
*/

void D_ArbitrateNetStart (void)
{
	int             i;
	boolean gotinfo[MAXNETNODES];
	
	autostart = true;
	memset (gotinfo,0,sizeof(gotinfo));
	
	if (doomcom->consoleplayer)
	{       // listen for setup info from key player
		while (1)
		{
			CheckAbort ();
			if (!HGetPacket ())
				continue;
			if (netbuffer->checksum & NCMD_SETUP)
			{
				if (netbuffer->player != VERSION)
					I_Error ("Different DOOM versions cannot play a net game!");
				startskill = netbuffer->retransmitfrom & 15;
				deathmatch = (netbuffer->retransmitfrom & 0xc0) >> 6;
				nomonsters = (netbuffer->retransmitfrom & 0x20) > 0;
				respawnparm = (netbuffer->retransmitfrom & 0x10) > 0;
				startmap = netbuffer->starttic & 0x3f;
				startepisode = netbuffer->starttic >> 6;
				return;
			}
		}
	}
	else
	{       // key player, send the setup info
		do
		{
			CheckAbort ();
			for (i=0 ; i<doomcom->numnodes ; i++)
			{
				netbuffer->retransmitfrom = startskill;
				if (deathmatch)
					netbuffer->retransmitfrom |= (deathmatch<<6);
				if (nomonsters)
					netbuffer->retransmitfrom |= 0x20;
				if (respawnparm)
					netbuffer->retransmitfrom |= 0x10;
				netbuffer->starttic = startepisode * 64 + startmap;
				netbuffer->player = VERSION;
				netbuffer->numtics = 0;
				HSendPacket (i, NCMD_SETUP);
			}

#if 1
			for(i = 10 ; i  &&  HGetPacket(); --i)
			{
 if((netbuffer->player&0x7f) < MAXNETNODES)
				gotinfo[netbuffer->player&0x7f] = true;
			}
#else
			while (HGetPacket ())
			{
				gotinfo[netbuffer->player&0x7f] = true;
			}
#endif

			for (i=1 ; i<doomcom->numnodes ; i++)
				if (!gotinfo[i])
					break;
		} while (i < doomcom->numnodes);
	}
}

/*
===================
=
= D_CheckNetGame
=
= Works out player numbers among the net participants
===================
*/

extern  int                     viewangleoffset;

void D_CheckNetGame (void)
{
	int             i;
	
	for (i=0 ; i<MAXNETNODES ; i++)
	{
		nodeingame[i] = false;
	nettics[i] = 0;
		remoteresend[i] = false;        // set when local needs tics
		resendto[i] = 0;                        // which tic to start sending
	}
	
// I_InitNetwork sets doomcom and netgame
	I_InitNetwork ();
	if (doomcom->id != DOOMCOM_ID)
		I_Error ("Doomcom buffer invalid!");
	netbuffer = &doomcom->data;
	consoleplayer = displayplayer = doomcom->consoleplayer;
	if (netgame)
		D_ArbitrateNetStart ();
//printf ("startskill %i  deathmatch: %i  startmap: %i  startepisode: %i\n", startskill, deathmatch, startmap, startepisode);
	
// read values out of doomcom
	ticdup = doomcom->ticdup;
	maxsend = BACKUPTICS/2-1;
	if (maxsend<1)
		maxsend = 1;
			
	for (i=0 ; i<doomcom->numplayers ; i++)
		playeringame[i] = true;
	for (i=0 ; i<doomcom->numnodes ; i++)
		nodeingame[i] = true;
	
//printf ("player %i of %i (%i nodes)\n", consoleplayer+1, doomcom->numplayers, doomcom->numnodes);

}

/*
==================
=
= D_QuitNetGame
=
= Called before quitting to leave a net game without hanging the
= other players
=
==================
*/

void D_QuitNetGame (void)
{
	int             i, j;
	
	if (debugfile)
		fclose (debugfile);
		
	if (!netgame || !usergame || consoleplayer == -1 || demoplayback)
		return;
	
// send a bunch of packets for security
	netbuffer->player = consoleplayer;
	netbuffer->numtics = 0;
	for (i=0 ; i<4 ; i++)
	{
		for (j=1 ; j<doomcom->numnodes ; j++)
			if (nodeingame[j])
				HSendPacket (j, NCMD_EXIT);
		I_WaitVBL (1);
	}
}



/*
===============
=
= TryRunTics
=
===============
*/

int     frametics[4], frameon;
int     frameskip[4];
int             oldnettics;
extern  boolean advancedemo;

void TryRunTics (void)
{
	int             i;
	int             lowtic;
	int             entertic;
	static int              oldentertics;
	int                             realtics, availabletics;
	int                             counts;
	int                             numplaying;

//
// get real tics
//                      
	entertic = I_GetTime ()/ticdup;
	realtics = entertic - oldentertics;
	oldentertics = entertic;

//
// get available tics
//
	NetUpdate ();
	
	lowtic = MAXINT;
	numplaying = 0;
	for (i=0 ; i<doomcom->numnodes ; i++)
		if (nodeingame[i])
		{
			numplaying++;
			if (nettics[i] < lowtic)
				lowtic = nettics[i];
		}
	availabletics = lowtic - gametic/ticdup;
	

//
// decide how many tics to run
//
	if (realtics < availabletics-1)
		counts = realtics+1;
	else if (realtics < availabletics)
		counts = realtics;
	else
		counts = availabletics;
	if (counts < 1)
		counts = 1;
		
	frameon++;

if (debugfile)
	fprintf (debugfile,"=======real: %i  avail: %i  game: %i\n",realtics, availabletics,counts);

	if (!demoplayback)
	{       
	//=============================================================================
	//
	//      ideally nettics[0] should be 1 - 3 tics above lowtic
	//      if we are consistantly slower, speed up time
	//
		for (i=0 ; i<MAXPLAYERS ; i++)
			if (playeringame[i])
				break;
		if (consoleplayer == i)
		{       // the key player does not adapt
		}
		else
		{
			if (nettics[0] <= nettics[nodeforplayer[i]])
			{
				gametime--;
	//                      printf ("-");
			}
			frameskip[frameon&3] = (oldnettics > nettics[nodeforplayer[i]]);
			oldnettics = nettics[0];
			if (frameskip[0] && frameskip[1] && frameskip[2] && frameskip[3])
			{
				skiptics = 1;
	//                      printf ("+");
			}
		}
	//============================================================================= 
	}       // demoplayback                 

	//
	// wait for new tics if needed
	//
		while (lowtic < gametic/ticdup + counts)        
		{
	
			NetUpdate ();   
			lowtic = MAXINT;
			
			for (i=0 ; i<doomcom->numnodes ; i++)
				if (nodeingame[i] && nettics[i] < lowtic)
					lowtic = nettics[i];
	
			if (lowtic < gametic/ticdup)
				I_Error ("TryRunTics: lowtic < gametic");
				
			// don't stay in here forever -- give the menu a chance to work
			if (I_GetTime ()/ticdup - entertic >= 20)
			{
				MN_Ticker ();
				return;
			} 
		}

//
// run the count * ticdup dics
//
	while (counts--)
	{
		for (i=0 ; i<ticdup ; i++)
		{
			if (gametic/ticdup > lowtic)
				I_Error ("gametic>lowtic");
			if (advancedemo)
				D_DoAdvanceDemo ();
			MN_Ticker ();
			G_Ticker ();
			gametic++;
			//
			// modify command for duplicated tics
			//
			if (i != ticdup-1)
			{
				ticcmd_t        *cmd;
				int                     buf;
				int                     j;
				
				buf = (gametic/ticdup)%BACKUPTICS; 
				for (j=0 ; j<MAXPLAYERS ; j++)
				{
					cmd = &netcmds[j][buf];
					cmd->chatchar = 0;
					if (cmd->buttons & BT_SPECIAL)
						cmd->buttons = 0;
				}
			}
		}
		NetUpdate ();                                   // check for new console commands
	}
}