// Emacs style mode select   -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id: d_net.c,v 1.2 2000-08-12 21:29:25 fraggle Exp $
//
// Copyright (C) 1993-1996 by 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
//
// DESCRIPTION:
//      DOOM Network game communication and protocol,
//      all OS independend parts.
//
//-----------------------------------------------------------------------------

static const char rcsid[] =
"$Id: d_net.c,v 1.2 2000-08-12 21:29:25 fraggle Exp $";

#include "doomstat.h"
#include "m_menu.h"
#include "i_system.h"
#include "i_video.h"
#include "i_net.h"
#include "g_game.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;
int      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;

extern int  key_escape;                // phares


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

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

  c = 0x1234567;

// FIXME -endianess?
//#ifdef NORMALUNIX
//    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");
      exitmsg[7] += netconsole;
      players[consoleplayer].message = exitmsg;
      if (demorecording)
        G_CheckDemoStatus ();
      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)      // phares
      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
    printf("listening for network start info...\n");
    while (1)
    {
      CheckAbort ();
      if (!HGetPacket ())
          continue;
      if (netbuffer->checksum & NCMD_SETUP)
      {
        printf("Received %d %d\n",
	       netbuffer->retransmitfrom,netbuffer->starttic);
        startskill = netbuffer->retransmitfrom & 15;
        deathmatch = (netbuffer->retransmitfrom & 0xc0) >> 6;
        nomonsters = (netbuffer->retransmitfrom & 0x20) > 0;
        respawnparm = (netbuffer->retransmitfrom & 0x10) > 0;
        startmap = netbuffer->starttic & 0x3f;
        startepisode = 1 + (netbuffer->starttic >> 6);

        // killough 5/2/98: Read the options
	//
	// killough 11/98: NOTE: this code produces no inconsistency errors.
	// However, TeamTNT's code =does= produce inconsistencies. Go figur.

        G_ReadOptions((char *) netbuffer->cmds);

	// killough 12/98: removed obsolete compatibility flag and
	// removed printf()'s, since there are too many options to
	// make it manageable. It will be understood that the main
	// player controls the sync-critical options.

        return;
      }
    }
  }
  else
  {
    // key player, send the setup info
    puts("sending network start 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-1) * 64 + startmap;
        netbuffer->player = VERSION;

        // killough 5/2/98: Make sure we have enough room for options
        // If not, either GAME_OPTION_SIZE needs to be reduced, or
        // BACKUPTICS needs to increased, or we need to send several
        // packets instead of one.

        if (GAME_OPTION_SIZE > sizeof netbuffer->cmds)
          I_Error("D_ArbitrateNetStart: GAME_OPTION_SIZE"
                  " too large w.r.t. BACKUPTICS");

        G_WriteOptions((char *) netbuffer->cmds);    // killough 12/98

        // killough 5/2/98: Always write the maximum number of tics.
        netbuffer->numtics = BACKUPTICS;

        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*ticdup)-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];
int     frameon;
int     frameskip[4];
int     oldnettics;

extern boolean advancedemo;

void TryRunTics (void)
{
  int         i;
  int         lowtic;
  int         entertic;
  static int  oldentertics;
  int         realtics;
  int         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)
    {
      M_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 ();
      M_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
  }
}

//----------------------------------------------------------------------------
//
// $Log: d_net.c,v $
// Revision 1.2  2000-08-12 21:29:25  fraggle
// change license header
//
// Revision 1.1.1.1  2000/07/29 13:20:39  fraggle
// imported sources
//
// Revision 1.12  1998/05/21  12:12:09  jim
// Removed conditional from net code
//
// Revision 1.11  1998/05/16  09:40:57  jim
// formatted net files, installed temp switch for testing Stan/Lee's version
//
// Revision 1.10  1998/05/12  12:46:08  phares
// Removed OVER_UNDER code
//
// Revision 1.9  1998/05/05  16:28:58  phares
// Removed RECOIL and OPT_BOBBING defines
//
// Revision 1.8  1998/05/03  23:40:34  killough
// Fix net consistency problems, using G_WriteOptions/G_Readoptions
//
// Revision 1.7  1998/04/15  14:41:36  stan
// Now encode startepisode-1 in netbuffer->starttic because episode 4
// caused an overflow in the byte used for starttic.  Don't know how it
// ever worked!
//
// Revision 1.6  1998/04/13  10:40:48  stan
// Now synch up all items identified by Lee Killough as essential to
// game synch (including bobbing, recoil, rngseed).  Commented out
// code in g_game.c so rndseed is always set even in netgame.
//
// Revision 1.5  1998/02/15  02:47:36  phares
// User-defined keys
//
// Revision 1.4  1998/01/26  19:23:07  phares
// First rev with no ^Ms
//
// Revision 1.3  1998/01/26  05:47:28  killough
// add missing right brace
//
// Revision 1.2  1998/01/19  16:38:10  rand
// Added dummy comments to be reomved later
//
// Revision 1.1.1.1  1998/01/19  14:02:53  rand
// Lee's Jan 19 sources
//
//
//----------------------------------------------------------------------------
