/**************************************************************************
 *
 * environment.c -- mgquery environment functions
 * Copyright (C) 1994  Neil Sharman
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * $Id$
 *
 **************************************************************************/

/*
   $Log$
   Revision 1.2  2004/04/25 23:01:18  kjdon
   added a new -M option to mg_passes, allowing maxnumeric to be altered - made this change to keep gsdl3 mg inline with gsdl2 mg.

   Revision 1.1  2003/02/20 21:18:23  mdewsnip
   Addition of MG package for search and retrieval

   Revision 1.1  1999/08/10 21:17:50  sjboddie
   renamed mg-1.3d directory mg

   Revision 1.1  1998/11/17 09:34:37  rjmcnab
   *** empty log message ***

   * Revision 1.5  1995/03/14  05:15:26  tes
   * Updated the boolean query optimiser to do different types of optimisation.
   * A query environment variable "optimise_type" specifies which one is to be
   * used. Type 1 is the new one which is faster than 2.
   *
   * Revision 1.4  1994/11/25  03:47:43  tes
   * Committing files before adding the merge stuff.
   *
   * Revision 1.3  1994/10/20  03:56:43  tes
   * I have rewritten the boolean query optimiser and abstracted out the
   * components of the boolean query.
   *
   * Revision 1.2  1994/09/20  04:41:25  tes
   * For version 1.1
   *
 */

static char *RCSID = "$Id$";

#include "sysfuncs.h"

#include "memlib.h"
#include "locallib.h"
#include "local_strings.h"
#include "messages.h"

#include "environment.h"

/* [RPAP - Feb 97: WIN32 Port] */
#ifdef __WIN32__
# define STRCASECMP      stricmp
#else
# define STRCASECMP      strcasecmp
#endif

typedef struct
  {
    char *Name, *Data;
    char *(*Constraint) (char *Old, char *New);
  }
EEntry;

typedef struct Env
  {
    EEntry *Environment;
    int NumEnv;
    struct Env *Next;
  }
Env;


char *ConstraintErrorStr;

static Env Base =
{NULL, 0, NULL};


/*
 * Add name and data to the environment (data may be NULL)
 * All names are converted to lower case
 * returns 0 on success, -1 on memory failure or -2 on constraint failure
 */
int 
SetEnv (char *name, char *data, char *(*Constraint) (char *, char *))
{
  int i;
  EEntry *newenv, *env = Base.Environment;

  if (data && *data == '\0')
    data = NULL;

  /* search for name in the environment */
  for (i = 0; i < Base.NumEnv && STRCASECMP (name, env->Name); i++, env++);  /* [RPAP - Feb 97: WIN32 Port] */

  /* if not found the increase the environment size */
  if (i >= Base.NumEnv)
    {
      if (Constraint)
	{
	  data = Constraint (NULL, data);
	  if (!data)
	    return (-2);
	}
      /* allocate memory for the new environment */
      newenv = Base.Environment ?
	Xrealloc (Base.Environment, sizeof (EEntry) * (Base.NumEnv + 1)) :
	Xmalloc (sizeof (EEntry) * (Base.NumEnv + 1));
      if (!newenv)
	return (-1);
      Base.Environment = newenv;
      env = &newenv[Base.NumEnv];
      env->Data = NULL;
      env->Name = NULL;
      env->Constraint = Constraint;
      env->Name = Xstrdup (name);
      if (!env->Name)
	return (-1);
      Base.NumEnv++;
      for (i = 0; env->Name[i]; i++)
	env->Name[i] = tolower (env->Name[i]);
    }
  if (env->Constraint)
    {
      data = env->Constraint (env->Data, data);
      if (!data)
	return (-2);
    }
  if (env->Data)
    Xfree (env->Data);
  env->Data = NULL;
  if (data && *data != '\0')
    {
      env->Data = Xstrdup (data);
      if (!env->Data)
	return (-1);
    }
  return (0);
}



/*
 * Returns the data associated with name. If Data = NULL then this routine
 * returns a pointer to "". If the specified name does not exist then this 
 * routine returns NULL.
 */
char *
GetEnv (char *name)
{
  int i;
  EEntry *env = Base.Environment;
  /* search for name in the environment */
  for (i = 0; i < Base.NumEnv && STRCASECMP (name, env->Name); i++, env++);  /* [RPAP - Feb 97: WIN32 Port] */

  if (i >= Base.NumEnv)
    return (NULL);

  return (env->Data ? env->Data : "");
}

/*
 * Returns the data associated with name. If Data = NULL then this routine
 * returns a pointer to "". If the specified name does not exist then this 
 * routine returns default.
 */
char *
GetDefEnv (char *name, char *def)
{
  char *data = GetEnv (name);
  return (data ? data : def);
}



/*
 * This function pushes the environment on to a stack and duplicated it in 
 * the current stack.
 *
 */
int 
PushEnv (void)
{
  Env *env = Xmalloc (sizeof (Env));
  int i;
  *env = Base;
  Base.Next = env;
  Base.Environment = NULL;
  Base.NumEnv = 0;
  for (i = 0; i < env->NumEnv; i++)
    if (SetEnv (env->Environment[i].Name, env->Environment[i].Data,
		env->Environment[i].Constraint))
      return (-1);
  return (0);
}

int 
PopEnv (void)
{
  Env *env;
  int i;
  if (!Base.Next)
    return (-1);
  for (i = 0; i < Base.NumEnv; i++)
    {
      Xfree (Base.Environment[i].Name);
      if (Base.Environment[i].Data)
	Xfree (Base.Environment[i].Data);
    }
  if (Base.Environment)
    Xfree (Base.Environment);
  env = Base.Next;
  Base = *env;
  Xfree (env);
  return (0);
}


/*
 * Count the number of environments on the stack, including the current one.
 *
 */
int 
EnvStackHeight (void)
{
  int i = 1;
  Env *env = &Base;
  while (env->Next)
    {
      i++;
      env = env->Next;
    }
  return (i);
}

/*
 * Delete environment variable name. If name does not exist it returns -1
 * otherwise it returns 0
 */
int 
UnsetEnv (char *name, int Force)
{
  int i;
  EEntry *env = Base.Environment;
  /* search for name in the environment */
  for (i = 0; i < Base.NumEnv && STRCASECMP (name, env->Name); i++, env++);  /* [RPAP - Feb 97: WIN32 Port] */

  if (i >= Base.NumEnv ||
      (Base.Environment[i].Constraint && !Force))
    return (-1);
  Xfree (Base.Environment[i].Name);
  if (Base.Environment[i].Data)
    Xfree (Base.Environment[i].Data);
  for (i++; i < Base.NumEnv; i++)
    Base.Environment[i - 1] = Base.Environment[i];
  Base.NumEnv--;
  if (Base.NumEnv == 0)
    {
      Xfree (Base.Environment);
      Base.Environment = NULL;
    }
  return (0);
}








/*
 * Returns the name of environment variable number i or NULL if i is greater 
 * than or equal to the number of environment variables. Names start from
 * zero. 
 */
char *
GetEnvName (int i)
{
  return (i < Base.NumEnv ? Base.Environment[i].Name : NULL);
}

static char *BooleanStrs[] =
{"false", "true", "no", "yes", "off", "on"};

static char *
BooleanCons (char *Old, char *New)
{
  int i;
  int old = -1, new = -1;
  if (Old)
    for (i = 0; i < sizeof (BooleanStrs) / sizeof (char *); i++)
      if (!STRCASECMP (Old, BooleanStrs[i]))  /* [RPAP - Feb 97: WIN32 Port] */
	{
	  old = i;
	  break;
	}
  if (New)
    for (i = 0; i < sizeof (BooleanStrs) / sizeof (char *); i++)
      if (!STRCASECMP (New, BooleanStrs[i]))  /* [RPAP - Feb 97: WIN32 Port] */
	{
	  new = i;
	  break;
	}
  if (new >= 0)
    return (New);
  if (!New)
    return (BooleanStrs[Old ? old ^ 1 : 0]);
  ConstraintErrorStr = "Invalid argument [true|false|yes|no|on|off] required";
  return (NULL);
}

/*
 * returns 0 or 1  for a boolean string
 * or default on a error
 */
int 
BooleanEnv (char *data, int def)
{
  int i;
  if (!data)
    return (def);
  for (i = 0; i < sizeof (BooleanStrs) / sizeof (char *); i++)
    if (!STRCASECMP (data, BooleanStrs[i]))  /* [RPAP - Feb 97: WIN32 Port] */
      return (i & 1);
  return (def);
}

/*
 * returns the value for a integer string
 * or default on a error
 */
mg_s_long 
IntEnv (char *data, mg_s_long def)
{
  mg_s_long val;
  char *ptr;
  if (!data)
    return (def);
  val = strtol (data, &ptr, 10);
  return *ptr ? def : val;
}

static char *
NumberCmp (char *num, int min, int max)
{
  char *err;
  int val;
  static char Err[100];
  ConstraintErrorStr = "Not a valid number";
  if (!num)
    return (NULL);
  val = strtol (num, &err, 10);
  if (*err)
    return (NULL);
  sprintf (Err, "Not in legal range [%d <= num <= %d]", min, max);
  ConstraintErrorStr = Err;
  if (val < min || val > max)
    return (NULL);
  return (num);
}

/*ARGSUSED */
static char *
MaxDocsCons (char *Old, char *New)
{
  if (!STRCASECMP (New, "all"))  /* [RPAP - Feb 97: WIN32 Port] */
    return (New);
  return (NumberCmp (New, 1, ((unsigned) (~0)) >> 1));
}

/*ARGSUSED */
static char *
MaxTermsCons (char *Old, char *New)
{
  if (!STRCASECMP (New, "all"))  /* [RPAP - Feb 97: WIN32 Port] */
    return (New);
  return (NumberCmp (New, 1, ((unsigned) (~0)) >> 1));
}

/* ARGSUSED */
static char *
BufferCons (char *Old, char *New)
{
  return (NumberCmp (New, 0, 16 * 1024 * 1024));
}

/* ARGSUSED */
static char *
MaxNodesCons (char *Old, char *New)
{
  if (!STRCASECMP (New, "all"))  /* [RPAP - Feb 97: WIN32 Port] */
    return (New);
  return (NumberCmp (New, 8, 256 * 1024 * 1024));
}

/* ARGSUSED */
static char *
MaxHashCons (char *Old, char *New)
{
  return (NumberCmp (New, 8, 256 * 1024 * 1024));
}

/* ARGSUSED */
static char *
MaxParasCons (char *Old, char *New)
{
  return (NumberCmp (New, 1, 256 * 1024 * 1024));
}

/* ARGSUSED */
static char *
MaxHeadsCons (char *Old, char *New)
{
  return (NumberCmp (New, 1, 1000));
}

/* ARGSUSED */
char *
OptimiseCons (char *Old, char *New)
{
  return (NumberCmp (New, 0, 2));
}

/* ARGSUSED */
char *
MaxNumericCons (char *Old, char *New)
{
  return (NumberCmp (New, 4, 512));
}


/*
 * Makes sure that New is a valid query type
 *
 */
/* ARGSUSED */
static char *
QueryCons (char *Old, char *New)
{
  static char *QueryStrs[] =
  {
    "boolean", "ranked",
    "docnums", "approx-ranked"};
  int i;
  int new = -1;
  if (New)
    for (i = 0; i < sizeof (QueryStrs) / sizeof (char *); i++)
      if (!STRCASECMP (New, QueryStrs[i]))  /* [RPAP - Feb 97: WIN32 Port] */
	{
	  new = i;
	  break;
	}
  if (new >= 0)
    return (New);
  ConstraintErrorStr = "Invalid argument [boolean|ranked|docnums|approx-ranked] required";
  return (NULL);
}

/*
 * Makes sure that New is a valid accum type
 *
 */
/* ARGSUSED */
static char *
AccumCons (char *Old, char *New)
{
  static char *AccumStrs[] =
  {
    "array", "splay_tree", "hash_table", "list"};
  int i;
  int new = -1;
  if (New)
    for (i = 0; i < sizeof (AccumStrs) / sizeof (char *); i++)
      if (!STRCASECMP (New, AccumStrs[i]))  /* [RPAP - Feb 97: WIN32 Port] */
	{
	  new = i;
	  break;
	}
  if (new >= 0)
    return (New);
  ConstraintErrorStr = "Invalid argument "
    "[array|splay_tree|hash_table|list] required";
  return (NULL);
}



/*
 * Makes sure that New is a valid output type type
 *
 */
/* ARGSUSED */
static char *
OutputTypeCons (char *Old, char *New)
{
  static char *OutputTypeStrs[] =
  {"text", "silent", "docnums",
   "count", "heads", "hilite"
#ifdef TREC_MODE
   ,"extras_for_trec"
#endif
  };

  int i;
  int new = -1;
  if (New)
    for (i = 0; i < sizeof (OutputTypeStrs) / sizeof (char *); i++)
      if (!STRCASECMP (New, OutputTypeStrs[i]))  /* [RPAP - Feb 97: WIN32 Port] */
	{
	  new = i;
	  break;
	}
  if (new >= 0)
    return (New);
  ConstraintErrorStr = "Invalid argument [text|silent|docnums|heads|count|hilite"
#ifdef TREC_MODE
    "|extras_for_trec"
#endif
    "] required";
  return (NULL);
}

/*
 * Makes sure that New is a valid query type
 *
 */
/* ARGSUSED */
char *
HiliteStyleCons (char *Old, char *New)
{
  static char *StyleStrs[] =
  {"bold", "underline"};
  int i;
  int new = -1;
  if (New)
    for (i = 0; i < sizeof (StyleStrs) / sizeof (char *); i++)
      if (!STRCASECMP (New, StyleStrs[i]))  /* [RPAP - Feb 97: WIN32 Port] */
	{
	  new = i;
	  break;
	}
  if (new >= 0)
    return (New);
  ConstraintErrorStr = "Invalid argument [bold|underline] required";
  return (NULL);
}

/* =========================================================================
 * Function: get_output_type
 * Description:
 *      Map a mode string onto a mode char e.g. OUTPUT_????
 * Input:
 * Output:
 *      The mode char which is a subrange value.
 * ========================================================================= */

char
get_output_type (void)
{
  char *env_str = GetDefEnv ("mode", "text");
  char ch1 = toupper (env_str[0]);
  char ch2 = toupper (env_str[1]);

  switch (ch1)
    {
    case 'T':
      return OUTPUT_TEXT;
    case 'S':
      return OUTPUT_SILENT;
    case 'E':
      return OUTPUT_EXTRAS;
    case 'C':
      return OUTPUT_COUNT;
    case 'D':
      return OUTPUT_DOCNUMS;
    case 'H':
      if (ch2 == 'E')
	return OUTPUT_HEADERS;
      else
	return OUTPUT_HILITE;
    default:
      FatalError (1, "Problem in output type switch");
    }

  return '\0';			/*shouldn't reach here -- keep compiler happy */
}

/* =========================================================================
 * Function: get_query_type
 * Description:
 *      Map a query type string onto a char.
 * Input:
 * Output:
 *      Query type char.
 * ========================================================================= */

char
get_query_type (void)
{
  char *env_str = GetDefEnv ("query", "boolean");
  char ch1 = toupper (env_str[0]);

  switch (ch1)
    {
    case 'R':
      return QUERY_RANKED;
    case 'A':
      return QUERY_APPROX;
    case 'B':
      return QUERY_BOOLEAN;
    case 'D':
      return QUERY_DOCNUMS;
    default:
      FatalError (1, "Problem in query type switch");
    }

  return '\0';			/*shouldn't reach here */
}



/*
 * This initialises certain environment variables
 *
 */
void 
InitEnv (void)
{
  SetEnv ("hilite_style", "underline", HiliteStyleCons);	/*[TS:Sep/94] */
  SetEnv ("briefstats", "off", BooleanCons);
  SetEnv ("diskstats", "off", BooleanCons);
  SetEnv ("expert", "false", BooleanCons);
  SetEnv ("mgdir", getenv ("MGDATA") ? getenv ("MGDATA") : ".", NULL);
  SetEnv ("mgname", "", NULL);
  SetEnv ("maxdocs", "all", MaxDocsCons);
  SetEnv ("memstats", "off", BooleanCons);
  SetEnv ("mode", "text", OutputTypeCons);
  SetEnv ("pager", getenv ("PAGER") ? getenv ("PAGER") : "more", NULL);
  SetEnv ("qfreq", "true", BooleanCons);
  SetEnv ("query", "boolean", QueryCons);
  SetEnv ("sizestats", "off", BooleanCons);
  SetEnv ("timestats", "off", BooleanCons);
  SetEnv ("verbatim", "off", BooleanCons);
  SetEnv ("sorted_terms", "on", BooleanCons);
  SetEnv ("accumulator_method", "array", AccumCons);
  SetEnv ("stop_at_max_accum", "off", BooleanCons);
  SetEnv ("buffer", "1048576", BufferCons);
  SetEnv ("max_accumulators", "50000", MaxNodesCons);
  SetEnv ("max_terms", "all", MaxTermsCons);
  SetEnv ("maxparas", "1000", MaxParasCons);
  SetEnv ("hash_tbl_size", "1000", MaxHashCons);
  SetEnv ("skip_dump", "skips.%d", NULL);
  SetEnv ("ranked_doc_sepstr", "---------------------------------- %n %w\\n", NULL);
  SetEnv ("doc_sepstr", "---------------------------------- %n\\n", NULL);
  SetEnv ("para_sepstr", "\\n######## PARAGRAPH %n ########\\n", NULL);
  SetEnv ("para_start", "***** Weight = %w *****\\n", NULL);
  SetEnv ("terminator", "", NULL);
  SetEnv ("heads_length", "50", MaxHeadsCons);
  SetEnv ("optimise_type", "1", OptimiseCons);	/*[TS:Mar/95] */
  SetEnv ("casefold", "on", BooleanCons);  /* [RPAP - Jan 97: Stem Index Change] */
  SetEnv ("stem", "on", BooleanCons);  /* [RPAP - Jan 97: Stem Index Change] */
  SetEnv ("term_freq", "off", BooleanCons);  /* [RPAP - Feb 97: Term Frequency] */
  SetEnv ("maxnumeric", "4", MaxNumericCons);  /* [sjboddie - Jun 2002: Max Numeric word length] */
}


void 
UninitEnv (void)
{
  char *name;
  while (PopEnv () == 0);
  while ((name = GetEnvName (0)) != 0)
    UnsetEnv (name, 1);
}