#include "intl.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifndef GNOME
/* taken from gnome-libs/libgnome/gnome-i18n.c ... */

static GHashTable *alias_table = NULL;

/*read an alias file for the locales*/
static void
read_aliases (char *file)
{
  FILE *fp;
  char buf[256];

  if (!alias_table)
    alias_table = g_hash_table_new (g_str_hash, g_str_equal);
  fp = fopen (file,"r");
  if (!fp)
    return;
  while (fgets (buf,256,fp)) {
    char *p;
    g_strstrip(buf);
    if(buf[0]=='#' || buf[0]=='\0')
      continue;
    p = strtok(buf,"\t ");
    if(!p) continue;
    p = strtok(NULL,"\t ");
    if(!p) continue;
    g_hash_table_insert (alias_table, g_strdup(buf), g_strdup(p));
  }
  fclose (fp);
}

static void
free_alias_cb(gpointer key, gpointer value, gpointer user_data)
{
  g_free(key);
  g_free(value);
}

static void
free_alias_table(void)
{
  if (!alias_table)
    return;
  g_hash_table_foreach(alias_table, free_alias_cb, NULL);
  g_hash_table_destroy(alias_table);
  alias_table = NULL;
}

/*return the un-aliased language as a newly allocated string*/
static char *
unalias_lang (char *lang)
{
  char *p;

  if(!alias_table) {
    read_aliases ("/usr/share/locale/locale.alias");
    read_aliases ("/usr/local/share/locale/locale.alias");
    read_aliases ("/usr/lib/X11/locale/locale.alias");
    read_aliases ("/usr/openwin/lib/locale/locale.alias");
  }
  while((p=g_hash_table_lookup(alias_table,lang)) && strcmp(p, lang))
    lang = p;
  return lang;
}

/* Mask for components of locale spec. The ordering here is from
 * least significant to most significant
 */
enum
{
  COMPONENT_CODESET =   1 << 0,
  COMPONENT_TERRITORY = 1 << 1,
  COMPONENT_MODIFIER =  1 << 2
};

/* Break an X/Open style locale specification into components
 */
static guint
explode_locale (const gchar *locale,
                gchar **language, 
                gchar **territory, 
                gchar **codeset, 
                gchar **modifier)
{
  const gchar *uscore_pos;
  const gchar *at_pos;
  const gchar *dot_pos;

  guint mask = 0;

  uscore_pos = strchr (locale, '_');
  dot_pos = strchr (uscore_pos ? uscore_pos : locale, '.');
  at_pos = strchr (dot_pos ? dot_pos : (uscore_pos ? uscore_pos : locale), '@');

  if (at_pos) {
    mask |= COMPONENT_MODIFIER;
    *modifier = g_strdup (at_pos);
  } else
    at_pos = locale + strlen (locale);

  if (dot_pos) {
    mask |= COMPONENT_CODESET;
    *codeset = g_new (gchar, 1 + at_pos - dot_pos);
    strncpy (*codeset, dot_pos, at_pos - dot_pos);
    (*codeset)[at_pos - dot_pos] = '\0';
  } else
    dot_pos = at_pos;

  if (uscore_pos) {
    mask |= COMPONENT_TERRITORY;
    *territory = g_new (gchar, 1 + dot_pos - uscore_pos);
    strncpy (*territory, uscore_pos, dot_pos - uscore_pos);
    (*territory)[dot_pos - uscore_pos] = '\0';
  } else
    uscore_pos = dot_pos;

  *language = g_new (gchar, 1 + uscore_pos - locale);
  strncpy (*language, locale, uscore_pos - locale);
  (*language)[uscore_pos - locale] = '\0';

  return mask;
}

/*
 * Compute all interesting variants for a given locale name -
 * by stripping off different components of the value.
 *
 * For simplicity, we assume that the locale is in
 * X/Open format: language[_territory][.codeset][@modifier]
 *
 * TODO: Extend this to handle the CEN format (see the GNUlibc docs)
 *       as well. We could just copy the code from glibc wholesale
 *       but it is big, ugly, and complicated, so I'm reluctant
 *       to do so when this should handle 99% of the time...
 */
static GList *
compute_locale_variants (const gchar *locale)
{
  GList *retval = NULL;

  gchar *language;
  gchar *territory;
  gchar *codeset;
  gchar *modifier;

  guint mask;
  guint i;

  g_return_val_if_fail (locale != NULL, NULL);

  mask = explode_locale (locale, &language, &territory, &codeset, &modifier);

  /* Iterate through all possible combinations, from least attractive
   * to most attractive.
   */
  for (i=0; i<=mask; i++)
    if ((i & ~mask) == 0)
      {
        gchar *val = g_strconcat(language,
                                 (i & COMPONENT_TERRITORY) ? territory : "",
                                 (i & COMPONENT_CODESET) ? codeset : "",
                                 (i & COMPONENT_MODIFIER) ? modifier : "",
                                 NULL);
        retval = g_list_prepend (retval, val);
      }

  g_free (language);
  if (mask & COMPONENT_CODESET)
    g_free (codeset);
  if (mask & COMPONENT_TERRITORY)
    g_free (territory);
  if (mask & COMPONENT_MODIFIER)
    g_free (modifier);

  return retval;
}

/* The following is (partly) taken from the gettext package.
   Copyright (C) 1995, 1996, 1997, 1998 Free Software Foundation, Inc.  */

static const gchar *
guess_category_value (const gchar *categoryname)
{
  const gchar *retval;

  /* The highest priority value is the `LANGUAGE' environment
     variable.  This is a GNU extension.  */
  retval = getenv ("LANGUAGE");
  if (retval != NULL && retval[0] != '\0')
    return retval;

  /* `LANGUAGE' is not set.  So we have to proceed with the POSIX
     methods of looking to `LC_ALL', `LC_xxx', and `LANG'.  On some
     systems this can be done by the `setlocale' function itself.  */

  /* Setting of LC_ALL overwrites all other.  */
  retval = getenv ("LC_ALL");  
  if (retval != NULL && retval[0] != '\0')
    return retval;

  /* Next comes the name of the desired category.  */
  retval = getenv (categoryname);
  if (retval != NULL && retval[0] != '\0')
    return retval;

  /* Last possibility is the LANG environment variable.  */
  retval = getenv ("LANG");
  if (retval != NULL && retval[0] != '\0')
    return retval;

  return NULL;
}

static GList *
get_language_list(const gchar *category_name)
{
  GList *list = NULL;
  gint c_locale_defined= FALSE;

  const gchar *category_value;
  gchar *category_memory, *orig_category_memory;

  if (!category_name)
    category_name= "LC_ALL";

  category_value = guess_category_value (category_name);
  if (! category_value)
    category_value = "C";
  orig_category_memory = category_memory =
    g_malloc (strlen (category_value)+1);
      
  while (category_value[0] != '\0') {
    while (category_value[0] != '\0' && category_value[0] == ':')
      ++category_value;
          
    if (category_value[0] != '\0') {
      char *cp= category_memory;
              
      while (category_value[0] != '\0' && category_value[0] != ':')
	*category_memory++= *category_value++;
              
      category_memory[0]= '\0'; 
      category_memory++;

      cp = unalias_lang(cp);
              
      if (strcmp (cp, "C") == 0)
	c_locale_defined= TRUE;
              
      list= g_list_concat (list, compute_locale_variants (cp));
    }
  }

  g_free (orig_category_memory);
      
  if (!c_locale_defined)
    list= g_list_append (list, "C");

  return list;
}

#endif

GList *
intl_get_language_list(void)
{
  static GList *list = NULL;

  if (!list) {
#ifdef GNOME
    list = gnome_i18n_get_language_list("LC_MESSAGES");
#else
    list = get_language_list("LC_MESSAGES");
    free_alias_table();
#endif
  }
  return list;
}

/* low numbers are better */
int
intl_score_locale(const gchar *locale)
{
  GList *list = intl_get_language_list();
  GList *tmp;
  int i;

  /* NULL is same as C locale */
  if (!locale)
    return g_list_length(list) - 1;
  for (tmp = list, i = 0; tmp; tmp = tmp->next, i++)
    if (!strcmp((char *)tmp->data, locale))
      break;
  if (!tmp) /* not found */
    i = G_MAXINT;
  return i;
}