/* Qt format strings.
   Copyright (C) 2003-2025 Free Software Foundation, Inc.
   Written by Bruno Haible <bruno@clisp.org>, 2003.

   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 3 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, see <https://www.gnu.org/licenses/>.  */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdbool.h>
#include <stdlib.h>

#include "format.h"
#include "xalloc.h"
#include "xvasprintf.h"
#include "gettext.h"

#define _(str) gettext (str)

/* Qt format strings are processed by QString::arg and are documented in
   qt-4.3.0/doc/html/qstring.html.
   A directive
     - starts with '%',
     - is optionally followed by 'L' (indicates locale-dependent processing),
     - is followed by one or two digits ('0' to '9'). %0n is equivalent to %n.
   An unterminated directive ('%' or '%L' not followed by a digit or at the
   end) is not an error.
   The first .arg() invocation replaces the %n with the lowest numbered n,
   the next .arg() invocation then replaces the %n with the second-lowest
   numbered n, and so on.
   This is inherently buggy because a '%' in the first replacement confuses
   the second .arg() invocation.
   To reduce this problem and introduce another one, there are also .arg()
   methods that take up to 9 strings and perform the replacements in one swoop.
   But this method works only on strings that contain no 'L' flags and only
   single-digit argument designators.
   Although %0 is supported, usually %1 denotes the first argument, %2 the
   second argument etc.  */

struct spec
{
  /* Number of format directives.  */
  size_t directives;

  /* True if the string supports the multi-argument .arg() methods, i.e. if it
     contains no 'L' flags and only single-digit argument designators.  */
  bool simple;

  /* Booleans telling which %nn was seen.  */
  size_t arg_count;
  bool args_used[100];
};


static void *
format_parse (const char *format, bool translated, char *fdi,
              char **invalid_reason)
{
  const char *const format_start = format;
  struct spec spec;
  struct spec *result;

  spec.directives = 0;
  spec.simple = true;
  spec.arg_count = 0;

  for (; *format != '\0';)
    if (*format++ == '%')
      {
        const char *dir_start = format - 1;
        bool locale_flag = false;

        if (*format == 'L')
          {
            locale_flag = true;
            format++;
          }
        if (*format >= '0' && *format <= '9')
          {
            /* A directive.  */
            size_t number;

            FDI_SET (dir_start, FMTDIR_START);
            spec.directives++;
            if (locale_flag)
              spec.simple = false;

            number = *format - '0';
            if (format[1] >= '0' && format[1] <= '9')
              {
                number = 10 * number + (format[1] - '0');
                spec.simple = false;
                format++;
              }

            while (spec.arg_count <= number)
              spec.args_used[spec.arg_count++] = false;
            spec.args_used[number] = true;

            FDI_SET (format, FMTDIR_END);

            format++;
          }
      }

  result = XMALLOC (struct spec);
  *result = spec;
  return result;
}

static void
format_free (void *descr)
{
  struct spec *spec = (struct spec *) descr;

  free (spec);
}

static int
format_get_number_of_directives (void *descr)
{
  struct spec *spec = (struct spec *) descr;

  return spec->directives;
}

static bool
format_check (void *msgid_descr, void *msgstr_descr, bool equality,
              formatstring_error_logger_t error_logger, void *error_logger_data,
              const char *pretty_msgid, const char *pretty_msgstr)
{
  struct spec *spec1 = (struct spec *) msgid_descr;
  struct spec *spec2 = (struct spec *) msgstr_descr;
  bool err = false;
  size_t i;

  if (spec1->simple && !spec2->simple)
    {
      if (error_logger)
        error_logger (error_logger_data,
                      _("'%s' is a simple format string, but '%s' is not: it contains an 'L' flag or a double-digit argument number"),
                      pretty_msgid, pretty_msgstr);
      err = true;
    }

  if (!err)
    for (i = 0; i < spec1->arg_count || i < spec2->arg_count; i++)
      {
        bool arg_used1 = (i < spec1->arg_count && spec1->args_used[i]);
        bool arg_used2 = (i < spec2->arg_count && spec2->args_used[i]);

        /* The translator cannot omit a %n from the msgstr because that would
           yield a "Argument missing" warning at runtime.  */
        if (arg_used1 != arg_used2)
          {
            if (error_logger)
              {
                if (arg_used1)
                  error_logger (error_logger_data,
                                _("a format specification for argument %zu doesn't exist in '%s'"),
                                i, pretty_msgstr);
                else
                  error_logger (error_logger_data,
                                _("a format specification for argument %zu, as in '%s', doesn't exist in '%s'"),
                                i, pretty_msgstr, pretty_msgid);
              }
            err = true;
            break;
          }
      }

  return err;
}


struct formatstring_parser formatstring_qt =
{
  format_parse,
  format_free,
  format_get_number_of_directives,
  NULL,
  format_check
};


#ifdef TEST

/* Test program: Print the argument list specification returned by
   format_parse for strings read from standard input.  */

#include <stdio.h>

static void
format_print (void *descr)
{
  struct spec *spec = (struct spec *) descr;
  size_t i;

  if (spec == NULL)
    {
      printf ("INVALID");
      return;
    }

  printf ("(");
  for (i = 0; i < spec->arg_count; i++)
    {
      if (i > 0)
        printf (" ");
      if (spec->args_used[i])
        printf ("*");
      else
        printf ("_");
    }
  printf (")");
}

int
main ()
{
  for (;;)
    {
      char *line = NULL;
      size_t line_size = 0;
      int line_len;
      char *invalid_reason;
      void *descr;

      line_len = getline (&line, &line_size, stdin);
      if (line_len < 0)
        break;
      if (line_len > 0 && line[line_len - 1] == '\n')
        line[--line_len] = '\0';

      invalid_reason = NULL;
      descr = format_parse (line, false, NULL, &invalid_reason);

      format_print (descr);
      printf ("\n");
      if (descr == NULL)
        printf ("%s\n", invalid_reason);

      free (invalid_reason);
      free (line);
    }

  return 0;
}

/*
 * For Emacs M-x compile
 * Local Variables:
 * compile-command: "/bin/sh ../libtool --tag=CC --mode=link gcc -o a.out -static -O -g -Wall -I.. -I../gnulib-lib -I../../gettext-runtime/intl -DHAVE_CONFIG_H -DTEST format-qt.c ../gnulib-lib/libgettextlib.la"
 * End:
 */

#endif /* TEST */
