/* mkdefsinc.c - Tool to create defs.inc

 * Copyright (C) 2015 g10 Code GmbH

 *

 * This file is free software; as a special exception the author gives

 * unlimited permission to copy and/or distribute it, with or without

 * modifications, as long as this notice is preserved.

 *

 * This file is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY, to the extent permitted by law; without even the

 * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 */

/* This tool needs to be build with command line supplied -D options

   for the various directory variables.  It is easier to do this in

   build file than to use fragile make rules and a template file.  */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <errno.h>

#include <time.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <unistd.h>

#define PGM "mkdefsinc"

/* We include config.h after all include files because the config.h

   values are not valid for the build platform but we need some values

   nevertheless.  */

#include "config.h"

static int verbose;

/* The usual free wrapper.  */

static void

xfree (void *a)

{

  if (a)

    free (a);

}

static char *

xmalloc (size_t n)

{

  char *p;

  p = malloc (n);

  if (!p)

    {

      fputs (PGM ": out of core\n", stderr);

      exit (1);

    }

  return p;

}

static char *

xstrdup (const char *string)

{

  char *p;

  p = xmalloc (strlen (string)+1);

  strcpy (p, string);

  return p;

}

/* Return a malloced string with the last modification date of the

   FILES.  Returns NULL on error.  */

static char *

get_date_from_files (char **files)

{

  const char *file;

  const char *usedfile = NULL;

  struct stat sb;

  struct tm *tp;

  int errors = 0;

  time_t stamp = 0;

  char *result;

  for (; (file = *files); files++)

    {

      if (!*file || !strcmp (file, ".") || !strcmp (file, ".."))

        continue;

      if (stat (file, &sb))

        {

          fprintf (stderr, PGM ": stat failed for '%s': %s\n",

                   file, strerror (errno));

          errors = 1;

          continue;

        }

      if (sb.st_mtime > stamp)

        {

          stamp = sb.st_mtime;

          usedfile = file;

        }

    }

  if (errors)

    exit (1);

  if (usedfile)

    fprintf (stderr, PGM ": taking date from '%s'\n", usedfile);

  tp = gmtime (&stamp);

  if (!tp)

    return NULL;

  result = xmalloc (4+1+2+1+2+1);

  snprintf (result, 4+1+2+1+2+1, "%04d-%02d-%02d",

            tp->tm_year + 1900, tp->tm_mon+1, tp->tm_mday);

  return result;

}

/* We need to escape file names for Texinfo.  */

static void

print_filename (const char *prefix, const char *name)

{

  const char *s;

  fputs (prefix, stdout);

  for (s=name; *s; s++)

    switch (*s)

      {

      case '@': fputs ("@atchar{}",        stdout); break;

      case '{': fputs ("@lbracechar{}",    stdout); break;

      case '}': fputs ("@rbracechar{}",    stdout); break;

      case ',': fputs ("@comma{}",         stdout); break;

      case '\\':fputs ("@backslashchar{}", stdout); break;

      case '#': fputs ("@hashchar{}",      stdout); break;

      default: putchar (*s); break;

      }

  putchar('\n');

}

int

main (int argc, char **argv)

{

  int last_argc = -1;

  char *opt_date = NULL;

  int monthoff;

  char *p, *pend;

  size_t n;

  /* Option parsing.  */

  if (argc)

    {

      argc--; argv++;

    }

  while (argc && last_argc != argc )

    {

      last_argc = argc;

      if (!strcmp (*argv, "--"))

        {

          argc--; argv++;

          break;

        }

      else if (!strcmp (*argv, "--help"))

        {

          fputs ("Usage: " PGM " [OPTION] [FILES]\n"

                 "Create defs.inc file.\nOptions:\n"

                 "  -C DIR         Change to DIR before doing anything\n"

                 "  --date STRING  Take publication date from STRING\n"

                 "  --verbose      Enable extra informational output\n"

                 "  --help         Display this help and exit\n"

                 , stdout);

          exit (0);

        }

      else if (!strcmp (*argv, "--verbose"))

        {

          verbose = 1;

          argc--; argv++;

        }

      else if (!strcmp (*argv, "-C"))

        {

          argc--; argv++;

          if (argc)

            {

              if (chdir (*argv))

                {

                  fprintf (stderr, PGM ": chdir to '%s' failed: %s\n",

                           *argv, strerror (errno));

                  exit (1);

                }

              argc--; argv++;

            }

        }

      else if (!strcmp (*argv, "--date"))

        {

          argc--; argv++;

          if (argc)

            {

              opt_date = xstrdup (*argv);

              argc--; argv++;

            }

        }

      else if (!strncmp (*argv, "--", 2))

        {

          fprintf (stderr, PGM ": unknown option '%s'\n", *argv);

          exit (1);

        }

    }

  if (opt_date && *opt_date)

    {

      time_t stamp;

      struct tm *tp;

      if (*opt_date == '2' && strlen (opt_date) >= 10

          && opt_date[4] == '-' && opt_date[7] == '-')

        {

          opt_date[10] = 0;

        }

      else if ((stamp = strtoul (opt_date, NULL, 10)) > 0

               && (tp = gmtime (&stamp)))

        {

          p = xmalloc (4+1+2+1+2+1);

          snprintf (p, 4+1+2+1+2+1, "%04d-%02d-%02d",

                    tp->tm_year + 1900, tp->tm_mon+1, tp->tm_mday);

          xfree (opt_date);

          opt_date = p;

        }

      else

        {

          fprintf (stderr, PGM ": bad date '%s'\n", opt_date);

          exit (1);

        }

    }

  else

    {

      xfree (opt_date);

      opt_date = argc? get_date_from_files (argv) : NULL;

    }

  if (!opt_date)

    {

      opt_date = xstrdup ("unknown");

      monthoff = 0;

    }

  else

    {

      const char *month = "?";

      switch (atoi (opt_date+5))

        {

        case  1: month = "January"; break;

        case  2: month = "February"; break;

        case  3: month = "March"; break;

        case  4: month = "April"; break;

        case  5: month = "May"; break;

        case  6: month = "June"; break;

        case  7: month = "July"; break;

        case  8: month = "August"; break;

        case  9: month = "September"; break;

        case 10: month = "October"; break;

        case 11: month = "November"; break;

        case 12: month = "December"; break;

        }

      n = strlen (opt_date) + strlen (month) + 2 + 1;

      p = xmalloc (n);

      snprintf (p, n, "%d %n%s %d",

                atoi (opt_date+8), &monthoff, month, atoi (opt_date));

      xfree (opt_date);

      opt_date = p;

    }

  fputs ("@c defs.inc                         -*- texinfo -*-\n"

         "@c Common and build specific constants for the manuals.\n"

         "@c This file has been created by " PGM ".\n\n", stdout);

  fputs ("@ifclear defsincincluded\n"

         "@set defsincincluded 1\n\n", stdout);

  fputs ("\n@c Flags\n\n", stdout);

  fputs ("\n@c Directories\n\n", stdout);

  /* print_filename ("@set BINDIR         ", GNUPG_BINDIR ); */

  fputs ("\n@c Version information a la version.texi\n\n", stdout);

  printf ("@set UPDATED %s\n", opt_date);

  printf ("@set UPDATED-MONTH %s\n", opt_date + monthoff);

  printf ("@set EDITION %s\n", PACKAGE_VERSION);

  printf ("@set VERSION %s\n", PACKAGE_VERSION);

  fputs ("\n@c Macros\n\n", stdout);

  /* Trailer.  */

  fputs ("\n"

         "@end ifclear\n"

         "\n"

         "@c Loc" "al Variables:\n"

         "@c buffer-read-only: t\n"

         "@c End:\n", stdout);

  if (ferror (stdout))

    {

      fprintf (stderr, PGM ": error writing to stdout: %s\n", strerror (errno));

      return 1;

    }

  return 0;

}