/*
     This file is part of GNUnet.
     (C) 2005, 2006 Christian Grothoff (and other contributing authors)

     GNUnet 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, or (at your
     option) any later version.

     GNUnet 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 GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file util/strings.c
 * @brief string functions
 * @author Nils Durner
 * @author Christian Grothoff
 */

#include "platform.h"
#if HAVE_ICONV
#include <iconv.h>
#endif
#include "gnunet_common.h"
#include "gnunet_strings_lib.h"

#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)

#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall)


/**
 * Fill a buffer of the given size with
 * count 0-terminated strings (given as varargs).
 * If "buffer" is NULL, only compute the amount of
 * space required (sum of "strlen(arg)+1").
 *
 * Unlike using "snprintf" with "%s", this function
 * will add 0-terminators after each string.  The
 * "GNUNET_string_buffer_tokenize" function can be
 * used to parse the buffer back into individual
 * strings.
 *
 * @param buffer the buffer to fill with strings, can
 *               be NULL in which case only the necessary
 *               amount of space will be calculated
 * @param size number of bytes available in buffer
 * @param count number of strings that follow
 * @param ... count 0-terminated strings to copy to buffer
 * @return number of bytes written to the buffer
 *         (or number of bytes that would have been written)
 */
size_t
GNUNET_STRINGS_buffer_fill (char *buffer, size_t size, unsigned int count,
			    ...)
{
  size_t needed;
  size_t slen;
  const char *s;
  va_list ap;

  needed = 0;
  va_start (ap, count);
  while (count > 0)
    {
      s = va_arg (ap, const char *);

      slen = strlen (s) + 1;
      if (buffer != NULL)
	{
	  GNUNET_assert (needed + slen <= size);
	  memcpy (&buffer[needed], s, slen);
	}
      needed += slen;
      count--;
    }
  va_end (ap);
  return needed;
}


/**
 * Given a buffer of a given size, find "count"
 * 0-terminated strings in the buffer and assign
 * the count (varargs) of type "const char**" to the
 * locations of the respective strings in the
 * buffer.
 *
 * @param buffer the buffer to parse
 * @param size size of the buffer
 * @param count number of strings to locate
 * @return offset of the character after the last 0-termination
 *         in the buffer, or 0 on error.
 */
unsigned int
GNUNET_STRINGS_buffer_tokenize (const char *buffer, size_t size,
				unsigned int count, ...)
{
  unsigned int start;
  unsigned int needed;
  const char **r;
  va_list ap;

  needed = 0;
  va_start (ap, count);
  while (count > 0)
    {
      r = va_arg (ap, const char **);

      start = needed;
      while ((needed < size) && (buffer[needed] != '\0'))
	needed++;
      if (needed == size)
	{
	  va_end (ap);
	  return 0;		/* error */
	}
      *r = &buffer[start];
      needed++;			/* skip 0-termination */
      count--;
    }
  va_end (ap);
  return needed;
}


/**
 * Convert a given filesize into a fancy human-readable format.
 *
 * @param size number of bytes
 * @return fancy representation of the size (possibly rounded) for humans
 */
char *
GNUNET_STRINGS_byte_size_fancy (unsigned long long size)
{
  const char *unit = _( /* size unit */ "b");
  char *ret;

  if (size > 5 * 1024)
    {
      size = size / 1024;
      unit = _( /* size unit */ "KiB");
      if (size > 5 * 1024)
	{
	  size = size / 1024;
	  unit = _( /* size unit */ "MiB");
	  if (size > 5 * 1024)
	    {
	      size = size / 1024;
	      unit = _( /* size unit */ "GiB");
	      if (size > 5 * 1024)
		{
		  size = size / 1024;
		  unit = _( /* size unit */ "TiB");
		}
	    }
	}
    }
  ret = GNUNET_malloc (32);
  GNUNET_snprintf (ret, 32, "%llu %s", size, unit);
  return ret;
}


/**
 * Convert the len characters long character sequence
 * given in input that is in the given charset
 * to UTF-8.
 * @return the converted string (0-terminated),
 *  if conversion fails, a copy of the orignal
 *  string is returned.
 */
char *
GNUNET_STRINGS_to_utf8 (const char *input, size_t len, const char *charset)
{
  char *ret;

#if ENABLE_NLS && HAVE_ICONV
  size_t tmpSize;
  size_t finSize;
  char *tmp;
  char *itmp;
  iconv_t cd;

  cd = iconv_open ("UTF-8", charset);
  if (cd == (iconv_t) - 1)
    {
      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "iconv_open");
      LOG (GNUNET_ERROR_TYPE_WARNING,
	   _("Character set requested was `%s'\n"), charset);
      ret = GNUNET_malloc (len + 1);
      memcpy (ret, input, len);
      ret[len] = '\0';
      return ret;
    }
  tmpSize = 3 * len + 4;
  tmp = GNUNET_malloc (tmpSize);
  itmp = tmp;
  finSize = tmpSize;
  if (iconv (cd,
#if FREEBSD || DARWIN || WINDOWS
	     (const char **) &input,
#else
	     (char **) &input,
#endif
	     &len, &itmp, &finSize) == SIZE_MAX)
    {
      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "iconv");
      iconv_close (cd);
      GNUNET_free (tmp);
      ret = GNUNET_malloc (len + 1);
      memcpy (ret, input, len);
      ret[len] = '\0';
      return ret;
    }
  ret = GNUNET_malloc (tmpSize - finSize + 1);
  memcpy (ret, tmp, tmpSize - finSize);
  ret[tmpSize - finSize] = '\0';
  GNUNET_free (tmp);
  if (0 != iconv_close (cd))
    LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "iconv_close");
  return ret;
#else
  ret = GNUNET_malloc (len + 1);
  memcpy (ret, input, len);
  ret[len] = '\0';
  return ret;
#endif
}


/**
 * Complete filename (a la shell) from abbrevition.
 * @param fil the name of the file, may contain ~/ or
 *        be relative to the current directory
 * @returns the full file name,
 *          NULL is returned on error
 */
char *
GNUNET_STRINGS_filename_expand (const char *fil)
{
  char *buffer;

#ifndef MINGW
  size_t len;
  size_t n;
  char *fm;
  const char *fil_ptr;
#else
  char *fn;
  long lRet;
#endif

  if (fil == NULL)
    return NULL;

#ifndef MINGW
  if (fil[0] == DIR_SEPARATOR)
    /* absolute path, just copy */
    return GNUNET_strdup (fil);
  if (fil[0] == '~')
    {
      fm = getenv ("HOME");
      if (fm == NULL)
	{
	  LOG (GNUNET_ERROR_TYPE_WARNING,
	       _
	       ("Failed to expand `$HOME': environment variable `HOME' not set"));
	  return NULL;
	}
      fm = GNUNET_strdup (fm);
      /* do not copy '~' */
      fil_ptr = fil + 1;

      /* skip over dir seperator to be consistent */
      if (fil_ptr[0] == DIR_SEPARATOR)
	fil_ptr++;
    }
  else
    {
      /* relative path */
      fil_ptr = fil;
      len = 512;
      fm = NULL;
      while (1)
	{
	  buffer = GNUNET_malloc (len);
	  if (getcwd (buffer, len) != NULL)
	    {
	      fm = buffer;
	      break;
	    }
	  if ((errno == ERANGE) && (len < 1024 * 1024 * 4))
	    {
	      len *= 2;
	      GNUNET_free (buffer);
	      continue;
	    }
	  GNUNET_free (buffer);
	  break;
	}
      if (fm == NULL)
	{
	  LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "getcwd");
	  buffer = getenv ("PWD");	/* alternative */
	  if (buffer != NULL)
	    fm = GNUNET_strdup (buffer);
	}
      if (fm == NULL)
	fm = GNUNET_strdup ("./");	/* give up */
    }
  n = strlen (fm) + 1 + strlen (fil_ptr) + 1;
  buffer = GNUNET_malloc (n);
  GNUNET_snprintf (buffer, n, "%s%s%s", fm,
		   (fm[strlen (fm) - 1] ==
		    DIR_SEPARATOR) ? "" : DIR_SEPARATOR_STR, fil_ptr);
  GNUNET_free (fm);
  return buffer;
#else
  fn = GNUNET_malloc (MAX_PATH + 1);

  if ((lRet = plibc_conv_to_win_path (fil, fn)) != ERROR_SUCCESS)
    {
      SetErrnoFromWinError (lRet);
      LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "plibc_conv_to_win_path");
      return NULL;
    }
  /* is the path relative? */
  if ((strncmp (fn + 1, ":\\", 2) != 0) && (strncmp (fn, "\\\\", 2) != 0))
    {
      char szCurDir[MAX_PATH + 1];

      lRet = GetCurrentDirectory (MAX_PATH + 1, szCurDir);
      if (lRet + strlen (fn) + 1 > (MAX_PATH + 1))
	{
	  SetErrnoFromWinError (ERROR_BUFFER_OVERFLOW);
	  LOG_STRERROR (GNUNET_ERROR_TYPE_WARNING, "GetCurrentDirectory");
	  return NULL;
	}
      buffer = GNUNET_malloc (MAX_PATH + 1);
      GNUNET_snprintf (buffer, MAX_PATH + 1, "%s\\%s", szCurDir, fn);
      GNUNET_free (fn);
      fn = buffer;
    }

  return fn;
#endif
}


/**
 * Give relative time in human-readable fancy format.
 *
 * @param delta time in milli seconds
 * @return time as human-readable string
 */
char *
GNUNET_STRINGS_relative_time_to_string (struct GNUNET_TIME_Relative delta)
{
  const char *unit = _( /* time unit */ "ms");
  char *ret;
  uint64_t dval = delta.rel_value;

  if (delta.rel_value == GNUNET_TIME_UNIT_FOREVER_REL.rel_value)
    return GNUNET_strdup (_("eternity"));
  if (dval > 5 * 1000)
    {
      dval = dval / 1000;
      unit = _( /* time unit */ "s");
      if (dval > 5 * 60)
	{
	  dval = dval / 60;
	  unit = _( /* time unit */ "m");
	  if (dval > 5 * 60)
	    {
	      dval = dval / 60;
	      unit = _( /* time unit */ "h");
	      if (dval > 5 * 24)
		{
		  dval = dval / 24;
		  unit = _( /* time unit */ " days");
		}
	    }
	}
    }
  GNUNET_asprintf (&ret, "%llu %s", dval, unit);
  return ret;
}


/**
 * "man ctime_r", except for GNUnet time; also, unlike ctime, the
 * return value does not include the newline character.
 *
 * @param t time to convert
 * @return absolute time in human-readable format
 */
char *
GNUNET_STRINGS_absolute_time_to_string (struct GNUNET_TIME_Absolute t)
{
  time_t tt;
  char *ret;

  if (t.abs_value == GNUNET_TIME_UNIT_FOREVER_ABS.abs_value)
    return GNUNET_strdup (_("end of time"));
  tt = t.abs_value / 1000;
#ifdef ctime_r
  ret = ctime_r (&tt, GNUNET_malloc (32));
#else
  ret = GNUNET_strdup (ctime (&tt));
#endif
  ret[strlen (ret) - 1] = '\0';
  return ret;
}



/* end of strings.c */