/*
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 "qwsvdef.h"


/*

*/

typedef struct
{
  int       s;
  dfunction_t   *f;
} prstack_t;

#define MAX_STACK_DEPTH   32
prstack_t pr_stack[MAX_STACK_DEPTH];
int     pr_depth;

#define LOCALSTACK_SIZE   2048
int     localstack[LOCALSTACK_SIZE];
int     localstack_used;


qboolean  pr_trace;
dfunction_t *pr_xfunction;
int     pr_xstatement;


int   pr_argc;

char *pr_opnames[] =
{
"DONE",

"MUL_F",
"MUL_V", 
"MUL_FV",
"MUL_VF",
 
"DIV",

"ADD_F",
"ADD_V", 
  
"SUB_F",
"SUB_V",

"EQ_F",
"EQ_V",
"EQ_S", 
"EQ_E",
"EQ_FNC",
 
"NE_F",
"NE_V", 
"NE_S",
"NE_E", 
"NE_FNC",
 
"LE",
"GE",
"LT",
"GT", 

"INDIRECT",
"INDIRECT",
"INDIRECT", 
"INDIRECT", 
"INDIRECT",
"INDIRECT", 

"ADDRESS", 

"STORE_F",
"STORE_V",
"STORE_S",
"STORE_ENT",
"STORE_FLD",
"STORE_FNC",

"STOREP_F",
"STOREP_V",
"STOREP_S",
"STOREP_ENT",
"STOREP_FLD",
"STOREP_FNC",

"RETURN",
  
"NOT_F",
"NOT_V",
"NOT_S", 
"NOT_ENT", 
"NOT_FNC", 
  
"IF",
"IFNOT",
  
"CALL0",
"CALL1",
"CALL2",
"CALL3",
"CALL4",
"CALL5",
"CALL6",
"CALL7",
"CALL8",
  
"STATE",
  
"GOTO", 
  
"AND",
"OR", 

"BITAND",
"BITOR"
};

char *PR_GlobalString (int ofs);
char *PR_GlobalStringNoContents (int ofs);


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

/*
=================
PR_PrintStatement
=================
*/
void PR_PrintStatement (dstatement_t *s)
{
  int   i;
  
  if ( (unsigned)s->op < sizeof(pr_opnames)/sizeof(pr_opnames[0]))
  {
    Con_Printf ("%s ",  pr_opnames[s->op]);
    i = strlen(pr_opnames[s->op]);
    for ( ; i<10 ; i++)
      Con_Printf (" ");
  }
    
  if (s->op == OP_IF || s->op == OP_IFNOT)
    Con_Printf ("%sbranch %i",PR_GlobalString(s->a),s->b);
  else if (s->op == OP_GOTO)
  {
    Con_Printf ("branch %i",s->a);
  }
  else if ( (unsigned)(s->op - OP_STORE_F) < 6)
  {
    Con_Printf ("%s",PR_GlobalString(s->a));
    Con_Printf ("%s", PR_GlobalStringNoContents(s->b));
  }
  else
  {
    if (s->a)
      Con_Printf ("%s",PR_GlobalString(s->a));
    if (s->b)
      Con_Printf ("%s",PR_GlobalString(s->b));
    if (s->c)
      Con_Printf ("%s", PR_GlobalStringNoContents(s->c));
  }
  Con_Printf ("\n");
}

/*
============
PR_StackTrace
============
*/
void PR_StackTrace (void)
{
  dfunction_t *f;
  int     i;
  
  if (pr_depth == 0)
  {
    Con_Printf ("<NO STACK>\n");
    return;
  }
  
  pr_stack[pr_depth].f = pr_xfunction;
  for (i=pr_depth ; i>=0 ; i--)
  {
    f = pr_stack[i].f;
    
    if (!f)
    {
      Con_Printf ("<NO FUNCTION>\n");
    }
    else
      Con_Printf ("%12s : %s\n", PR_GetString(f->s_file), PR_GetString(f->s_name));   
  }
}


/*
============
PR_Profile_f

============
*/
void PR_Profile_f (void)
{
  dfunction_t *f, *best;
  int     max;
  int     num;
  int     i;
  
  num = 0;  
  do
  {
    max = 0;
    best = NULL;
    for (i=0 ; i<progs->numfunctions ; i++)
    {
      f = &pr_functions[i];
      if (f->profile > max)
      {
        max = f->profile;
        best = f;
      }
    }
    if (best)
    {
      if (num < 10)
        Con_Printf ("%7i %s\n", best->profile, PR_GetString(best->s_name));
      num++;
      best->profile = 0;
    }
  } while (best);
}


/*
============
PR_RunError

Aborts the currently executing function
============
*/
void PR_RunError (char *error, ...)
{
  va_list   argptr;
  char    string[1024];

  va_start (argptr,error);
  vsprintf (string,error,argptr);
  va_end (argptr);

  PR_PrintStatement (pr_statements + pr_xstatement);
  PR_StackTrace ();
  Con_Printf ("%s\n", string);
  
  pr_depth = 0;   // dump the stack so SV_Error can shutdown functions

  SV_Error ("Program error");
}

/*
============================================================================
PR_ExecuteProgram

The interpretation main loop
============================================================================
*/

/*
====================
PR_EnterFunction

Returns the new program statement counter
====================
*/
int PR_EnterFunction (dfunction_t *f)
{
  int   i, j, c, o;

  pr_stack[pr_depth].s = pr_xstatement;
  pr_stack[pr_depth].f = pr_xfunction;  
  pr_depth++;
  if (pr_depth >= MAX_STACK_DEPTH)
    PR_RunError ("stack overflow");

// save off any locals that the new function steps on
  c = f->locals;
  if (localstack_used + c > LOCALSTACK_SIZE)
    PR_RunError ("PR_ExecuteProgram: locals stack overflow\n");

  for (i=0 ; i < c ; i++)
    localstack[localstack_used+i] = ((int *)pr_globals)[f->parm_start + i];
  localstack_used += c;

// copy parameters
  o = f->parm_start;
  for (i=0 ; i<f->numparms ; i++)
  {
    for (j=0 ; j<f->parm_size[i] ; j++)
    {
      ((int *)pr_globals)[o] = ((int *)pr_globals)[OFS_PARM0+i*3+j];
      o++;
    }
  }

  pr_xfunction = f;
  return f->first_statement - 1;  // offset the s++
}

/*
====================
PR_LeaveFunction
====================
*/
int PR_LeaveFunction (void)
{
  int   i, c;

  if (pr_depth <= 0)
    SV_Error ("prog stack underflow");

// restore locals from the stack
  c = pr_xfunction->locals;
  localstack_used -= c;
  if (localstack_used < 0)
    PR_RunError ("PR_ExecuteProgram: locals stack underflow\n");

  for (i=0 ; i < c ; i++)
    ((int *)pr_globals)[pr_xfunction->parm_start + i] = localstack[localstack_used+i];

// up stack
  pr_depth--;
  pr_xfunction = pr_stack[pr_depth].f;
  return pr_stack[pr_depth].s;
}


/*
====================
PR_ExecuteProgram
====================
*/
void PR_ExecuteProgram (func_t fnum)
{
  eval_t  *a, *b, *c;
  int     s;
  dstatement_t  *st;
  dfunction_t *f, *newf;
  int   runaway;
  int   i;
  edict_t *ed;
  int   exitdepth;
  eval_t  *ptr;

  if (!fnum || fnum >= progs->numfunctions)
  {
    if (pr_global_struct->self)
      ED_Print (PROG_TO_EDICT(pr_global_struct->self));
    SV_Error ("PR_ExecuteProgram: NULL function");
  }
  
  f = &pr_functions[fnum];

  runaway = 100000;
  pr_trace = false;

// make a stack frame
  exitdepth = pr_depth;

  s = PR_EnterFunction (f);
  
while (1)
{
  s++;  // next statement

  st = &pr_statements[s];
  a = (eval_t *)&pr_globals[st->a];
  b = (eval_t *)&pr_globals[st->b];
  c = (eval_t *)&pr_globals[st->c];
  
  if (--runaway == 0)
    PR_RunError ("runaway loop error");
    
  pr_xfunction->profile++;
  pr_xstatement = s;
  
  if (pr_trace)
    PR_PrintStatement (st);
    
  switch (st->op)
  {
  case OP_ADD_F:
    c->_float = a->_float + b->_float;
    break;
  case OP_ADD_V:
    c->vector[0] = a->vector[0] + b->vector[0];
    c->vector[1] = a->vector[1] + b->vector[1];
    c->vector[2] = a->vector[2] + b->vector[2];
    break;
    
  case OP_SUB_F:
    c->_float = a->_float - b->_float;
    break;
  case OP_SUB_V:
    c->vector[0] = a->vector[0] - b->vector[0];
    c->vector[1] = a->vector[1] - b->vector[1];
    c->vector[2] = a->vector[2] - b->vector[2];
    break;

  case OP_MUL_F:
    c->_float = a->_float * b->_float;
    break;
  case OP_MUL_V:
    c->_float = a->vector[0]*b->vector[0]
        + a->vector[1]*b->vector[1]
        + a->vector[2]*b->vector[2];
    break;
  case OP_MUL_FV:
    c->vector[0] = a->_float * b->vector[0];
    c->vector[1] = a->_float * b->vector[1];
    c->vector[2] = a->_float * b->vector[2];
    break;
  case OP_MUL_VF:
    c->vector[0] = b->_float * a->vector[0];
    c->vector[1] = b->_float * a->vector[1];
    c->vector[2] = b->_float * a->vector[2];
    break;

  case OP_DIV_F:
    c->_float = a->_float / b->_float;
    break;
  
  case OP_BITAND:
    c->_float = (int)a->_float & (int)b->_float;
    break;
  
  case OP_BITOR:
    c->_float = (int)a->_float | (int)b->_float;
    break;
  
    
  case OP_GE:
    c->_float = a->_float >= b->_float;
    break;
  case OP_LE:
    c->_float = a->_float <= b->_float;
    break;
  case OP_GT:
    c->_float = a->_float > b->_float;
    break;
  case OP_LT:
    c->_float = a->_float < b->_float;
    break;
  case OP_AND:
    c->_float = a->_float && b->_float;
    break;
  case OP_OR:
    c->_float = a->_float || b->_float;
    break;
    
  case OP_NOT_F:
    c->_float = !a->_float;
    break;
  case OP_NOT_V:
    c->_float = !a->vector[0] && !a->vector[1] && !a->vector[2];
    break;
  case OP_NOT_S:
    c->_float = !a->string || !*PR_GetString(a->string);
    break;
  case OP_NOT_FNC:
    c->_float = !a->function;
    break;
  case OP_NOT_ENT:
    c->_float = (PROG_TO_EDICT(a->edict) == sv.edicts);
    break;

  case OP_EQ_F:
    c->_float = a->_float == b->_float;
    break;
  case OP_EQ_V:
    c->_float = (a->vector[0] == b->vector[0]) &&
          (a->vector[1] == b->vector[1]) &&
          (a->vector[2] == b->vector[2]);
    break;
  case OP_EQ_S:
    c->_float = !strcmp(PR_GetString(a->string), PR_GetString(b->string));
    break;
  case OP_EQ_E:
    c->_float = a->_int == b->_int;
    break;
  case OP_EQ_FNC:
    c->_float = a->function == b->function;
    break;


  case OP_NE_F:
    c->_float = a->_float != b->_float;
    break;
  case OP_NE_V:
    c->_float = (a->vector[0] != b->vector[0]) ||
          (a->vector[1] != b->vector[1]) ||
          (a->vector[2] != b->vector[2]);
    break;
  case OP_NE_S:
    c->_float = strcmp(PR_GetString(a->string), PR_GetString(b->string));
    break;
  case OP_NE_E:
    c->_float = a->_int != b->_int;
    break;
  case OP_NE_FNC:
    c->_float = a->function != b->function;
    break;

//==================
  case OP_STORE_F:
  case OP_STORE_ENT:
  case OP_STORE_FLD:    // integers
  case OP_STORE_S:
  case OP_STORE_FNC:    // pointers
    b->_int = a->_int;
    break;
  case OP_STORE_V:
    b->vector[0] = a->vector[0];
    b->vector[1] = a->vector[1];
    b->vector[2] = a->vector[2];
    break;
    
  case OP_STOREP_F:
  case OP_STOREP_ENT:
  case OP_STOREP_FLD:   // integers
  case OP_STOREP_S:
  case OP_STOREP_FNC:   // pointers
    ptr = (eval_t *)((byte *)sv.edicts + b->_int);
    ptr->_int = a->_int;
    break;
  case OP_STOREP_V:
    ptr = (eval_t *)((byte *)sv.edicts + b->_int);
    ptr->vector[0] = a->vector[0];
    ptr->vector[1] = a->vector[1];
    ptr->vector[2] = a->vector[2];
    break;
    
  case OP_ADDRESS:
    ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
    NUM_FOR_EDICT(ed);    // make sure it's in range
#endif
    if (ed == (edict_t *)sv.edicts && sv.state == ss_active)
      PR_RunError ("assignment to world entity");
    c->_int = (byte *)((int *)&ed->v + b->_int) - (byte *)sv.edicts;
    break;
    
  case OP_LOAD_F:
  case OP_LOAD_FLD:
  case OP_LOAD_ENT:
  case OP_LOAD_S:
  case OP_LOAD_FNC:
    ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
    NUM_FOR_EDICT(ed);    // make sure it's in range
#endif
    a = (eval_t *)((int *)&ed->v + b->_int);
    c->_int = a->_int;
    break;

  case OP_LOAD_V:
    ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
    NUM_FOR_EDICT(ed);    // make sure it's in range
#endif
    a = (eval_t *)((int *)&ed->v + b->_int);
    c->vector[0] = a->vector[0];
    c->vector[1] = a->vector[1];
    c->vector[2] = a->vector[2];
    break;
    
//==================

  case OP_IFNOT:
    if (!a->_int)
      s += st->b - 1; // offset the s++
    break;
    
  case OP_IF:
    if (a->_int)
      s += st->b - 1; // offset the s++
    break;
    
  case OP_GOTO:
    s += st->a - 1; // offset the s++
    break;
    
  case OP_CALL0:
  case OP_CALL1:
  case OP_CALL2:
  case OP_CALL3:
  case OP_CALL4:
  case OP_CALL5:
  case OP_CALL6:
  case OP_CALL7:
  case OP_CALL8:
    pr_argc = st->op - OP_CALL0;
    if (!a->function)
      PR_RunError ("NULL function");

    newf = &pr_functions[a->function];

    if (newf->first_statement < 0)
    { // negative statements are built in functions
      i = -newf->first_statement;
      if (i >= pr_numbuiltins)
        PR_RunError ("Bad builtin call number");
      pr_builtins[i] ();
      break;
    }

    s = PR_EnterFunction (newf);
    break;

  case OP_DONE:
  case OP_RETURN:
    pr_globals[OFS_RETURN] = pr_globals[st->a];
    pr_globals[OFS_RETURN+1] = pr_globals[st->a+1];
    pr_globals[OFS_RETURN+2] = pr_globals[st->a+2];
  
    s = PR_LeaveFunction ();
    if (pr_depth == exitdepth)
      return;   // all done
    break;
    
  case OP_STATE:
    ed = PROG_TO_EDICT(pr_global_struct->self);
    ed->v.nextthink = pr_global_struct->time + 0.1;
    if (a->_float != ed->v.frame)
    {
      ed->v.frame = a->_float;
    }
    ed->v.think = b->function;
    break;
    
  default:
    PR_RunError ("Bad opcode %i", st->op);
  }
}

}

/*----------------------*/

char *pr_strtbl[MAX_PRSTR];
int num_prstr;

char *PR_GetString(int num)
{
  if (num < 0) {
//Con_DPrintf("GET:%d == %s\n", num, pr_strtbl[-num]);
    return pr_strtbl[-num];
  }
  return pr_strings + num;
}

int PR_SetString(char *s)
{
  int i;

  if (s - pr_strings < 0) {
    for (i = 0; i <= num_prstr; i++)
      if (pr_strtbl[i] == s)
        break;
    if (i < num_prstr)
      return -i;
    if (num_prstr == MAX_PRSTR - 1)
      Sys_Error("MAX_PRSTR");
    num_prstr++;
    pr_strtbl[num_prstr] = s;
//Con_DPrintf("SET:%d == %s\n", -num_prstr, s);
    return -num_prstr;
  }
  return (int)(s - pr_strings);
}