/* Environment test program for GNU Pies.
   Copyright (C) 2019 Sergey Poznyakoff

   GNU Pies 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, or (at your option)
   any later version.

   GNU Pies 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 GNU Pies.  If not, see <http://www.gnu.org/licenses/>. */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <ctype.h>
#include <envop.h>
#include <wordsplit.h>

static int
envcmp (void const *a, void const *b)
{
  char const *as = *(char const **)a;
  char const *bs = *(char const **)b;
  int c;
  
  while (*as && *bs)
    {
      c = *as - *bs;
      if (c || *as == '=' || *bs == '=')
	break;
      as++;
      bs++;
    }
  return c;
}

static void
sortenv (char **env)
{
  size_t n;
  for (n = 0; env[n]; n++)
    ;
  qsort (env, n, sizeof (env[0]), envcmp);
}

static void
printenv (char **env)
{
  size_t i;
  for (i = 0; env[i]; i++)
    {
      char *p = env[i];
      while (*p)
	{
	  fputc (*p, stdout);
	  if (*p++ == '=')
	    break;
	}
      if (*p)
	{
	  int c;
	  fputc ('"', stdout);
	  while ((c = *p++) != 0)
	    {
	      int c1;
	      if (isascii (c) && isprint (c) && c != '\\' && c != '"')
		fputc (c, stdout);
	      else if ((c1 = wordsplit_c_quote_char (c)))
		{
		  fputc ('\\', stdout);
		  fputc (c1, stdout);
		}
	    }
	  fputc ('"', stdout);
	}
      fputc ('\n', stdout);
    }
}

char *defenv[] = {
  "PATH=/usr/local/bin:/usr/bin:/bin",
  "HOME=/home/user",
  "USER=user",
  "LOGIN=user",
  "PWD=/home",
  "LC_ALL=C",
  "LC_CTYPE=C",
  "LC_MESSAGES=C",
  "LC_NUMERIC=C",
  NULL
};

extern char **environ;

int
main (int argc, char **argv)
{
  envop_t *envop = NULL;
  int opcode = envop_set;
  environ_t *env = NULL;

  if (argc > 1)
    {
      if (strcmp (argv[1], "-clone") == 0)
	{
	  env = environ_create (environ);
	  argc--;
	  argv++;
	}
      else if (strcmp (argv[1], "-null") == 0)
	{
	  env = environ_create (NULL);
	  argc--;
	  argv++;
	}
    }

  if (!env)
    env = environ_create (defenv);

  if (!env)
    {
      perror ("environ_create");
      abort ();
    }
  
  while (--argc)
    {
      char *a = *++argv;

      if (strcmp (a, "-set") == 0)
	opcode = envop_set;
      else if (strcmp (a, "-unset") == 0)
	opcode = envop_unset;
      else if (strcmp (a, "-keep") == 0)
	opcode = envop_keep;
      else if (strcmp (a, "-clear") == 0)
	{
	  int rc = envop_entry_add (&envop, envop_clear, NULL, NULL);
	  if (rc)
	    {
	      perror ("envop_entry_add");
	      return 1;
	    }
	}
      else if (strcmp (a, "-exec") == 0)
	{
	  --argc;
	  ++argv;
	  if (argc == 0)
	    {
	      fprintf (stderr, "program name required after -exec\n");
	      return 1;
	    }
	  break;
	}
      else if (a[0] == '-')
	{
	  fprintf (stderr, "unrecognized option: %s\n", a);
	  return 1;
	}
      else
	{
          int rc;
	  char *p = strchr (a, '=');

	  if (p)
	    *p++ = 0;
	  rc = envop_entry_add (&envop, opcode, a, p);

	  if (rc)
	    {
	      perror ("envop_entry_add");
	      return 1;
	    }
	}
    }

  if (envop_exec (envop, env))
    {
      perror ("envop_exec");
      return 1;
    }

  if (argc)
    {
      environ = environ_ptr (env);
      execvp (argv[0], argv);
      perror ("execvp");
      abort ();
    }
  
  sortenv (env->env_base);
  printenv (env->env_base);
  return 0;
}