/*
 * This file is part of Crossfire TRT, the Roguelike Realtime MORPG.
 * 
 * Copyright (©) 2005,2006,2007 Marc Alexander Lehmann / Robin Redeker / the Crossfire TRT team
 * Copyright (©) 2002,2007 Mark Wedel & Crossfire Development Team
 * Copyright (©) 1992,2007 Frank Tore Johansen
 * 
 * Crossfire TRT 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 <http://www.gnu.org/licenses/>.
 * 
 * The authors can be reached via e-mail to <crossfire@schmorp.de>
 */

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <global.h>

#include "define.h"
#include "path.h"


#if 0

/**
 * Define DEBUG_PATH to enable debug output.
 */
# define DEBUG_PATH
#endif

#if 0

/**
 * Define TEST_PATH to compile this file as a stand-alone self-test application
 * for the functions.
 */
# define TEST_PATH

# define LOG fprintf
# define llevDebug stderr
# define llevError stderr
#endif


char *
path_combine (const char *src, const char *dst)
{
  char *p;
  static char path[HUGE_BUF];

  if (*dst == '/')
    {
      /* absolute destination path => ignore source path */
      strcpy (path, dst);
    }
  else
    {
      /* relative destination path => add after last '/' of source */
      strcpy (path, src);
      p = strrchr (path, '/');
      if (p != NULL)
        {
          p++;
        }
      else
        {
          p = path;
          if (*src == '/')
            *p++ = '/';
        }
      strcpy (p, dst);
    }

#if defined(DEBUG_PATH)
  LOG (llevDebug, "path_combine(%s, %s) = %s\n", src, dst, path);
#endif
  return (path);
}

void
path_normalize (char *path)
{
  char *p;                      /* points to the beginning of the path not yet processed; this is
                                   either a path component or a path separator character */
  char *q;                      /* points to the end of the path component p points to */
  char *w;                      /* points to the end of the already normalized path; w <= p is
                                   maintained */
  size_t len;                   /* length of current component (which p points to) */

#if defined(DEBUG_PATH)
  LOG (llevDebug, "path_normalize: input '%s'\n", path);
#endif

  p = path;
  w = p;
  while (*p != '\0')
    {

      if (*p == '/')
        {
          if ((w == path && *path == '/') || (w > path && w[-1] != '/'))
            *w++ = '/';
          p++;
          continue;
        }

      q = strchr (p, '/');
      if (q == NULL)
        q = p + strlen (p);
      len = q - p;
      assert (len > 0);

#if defined(DEBUG_PATH)
      LOG (llevDebug, "path_normalize: checking '%.*s'\n", (int) len, p);
#endif

      if (len == 1 && *p == '.')
        {
          /* remove current component */
        }
      else if (len == 2 && memcmp (p, "..", 2) == 0)
        {
          if (w == path || (w == path + 3 && memcmp (path, "../", 3) == 0))
            {
              /* keep ".." at beginning of relative path ("../x" => "../x") */
              memmove (w, p, len);
              w += len;
            }
          else if (w == path + 1 && *path == '/')
            {
              /* remove ".." at beginning of absolute path ("/../x" => "/x") */
            }
          else
            {
              /* remove both current component ".." and preceding one */
              if (w > path && w[-1] == '/')
                w--;
              while (w > path && w[-1] != '/')
                w--;
            }
        }
      else
        {
          /* normal component ==> add it */
          memmove (w, p, len);
          w += len;
        }

      p = q;

#if defined(DEBUG_PATH)
      LOG (llevDebug, "path_normalize: so far '%.*s'\n", (int) (w - path), path);
#endif
    }

  /* remove trailing slashes, but keep the one at the start of the path */
  while (w > path + 1 && w[-1] == '/')
    {
      w--;
    }

  *w = '\0';

#if defined(DEBUG_PATH)
  LOG (llevDebug, "path_normalize: result '%s'\n", path);
#endif
}

char *
path_combine_and_normalize (const char *src, const char *dst)
{
  char *path;

  path = path_combine (src, dst);
  path_normalize (path);
  return (path);
}

#if defined(TEST_PATH)
static void
check_combine (const char *src, const char *dst, const char *exp)
{
  const char *res;

  fprintf (stderr, "path_combine(%s, %s) = ", src, dst);
  res = path_combine (src, dst);
  fprintf (stderr, "%s", res);
  if (strcmp (res, exp) != 0)
    {
      fprintf (stderr, ", should be %s\n", exp);
    }
  else
    {
      fprintf (stderr, " (OK)\n");
    }
}

static void
check_normalize (const char *path, const char *exp0)
{
  char tmp[HUGE_BUF];
  char exp[HUGE_BUF];

  strcpy (exp, exp0 == NULL ? path : exp0);

  strcpy (tmp, path);
  fprintf (stderr, "path_normalize(%s) = ", tmp);
  path_normalize (tmp);
  fprintf (stderr, "%s", tmp);
  if (strcmp (tmp, exp) != 0)
    {
      fprintf (stderr, ", should be %s\n", exp);
    }
  else
    {
      fprintf (stderr, " (OK)\n");
    }
}

static void
check_combine_and_normalize (const char *src, const char *dst, const char *exp)
{
  const char *res;

  fprintf (stderr, "path_combine_and_normalize(%s, %s) = ", src, dst);
  res = path_combine_and_normalize (src, dst);
  fprintf (stderr, "%s", res);
  if (strcmp (res, exp) != 0)
    {
      fprintf (stderr, ", should be %s\n", exp);
    }
  else
    {
      fprintf (stderr, " (OK)\n");
    }
}

int
main ()
{
  check_combine ("/path1/file1", "/path2/file2", "/path2/file2");
  check_combine ("path1/file1", "/path2/file2", "/path2/file2");
  check_combine ("/path1/file1", "path2/file2", "/path1/path2/file2");
  check_combine ("path1/file1", "path2/file2", "path1/path2/file2");
  check_combine ("/path1", "/path2", "/path2");
  check_combine ("path1", "/path2", "/path2");
  check_combine ("/path1", "path2", "/path2");
  check_combine ("path1", "path2", "path2");

  check_normalize ("", NULL);
  check_normalize ("/", NULL);
  check_normalize ("path1/file1", NULL);
  check_normalize ("/path1/file1", NULL);
  check_normalize ("/path1//file1", "/path1/file1");
  check_normalize ("//path1/file1", "/path1/file1");
  check_normalize ("///////x////////y///////z////////", "/x/y/z");
  check_normalize ("/a/b/../c/d/../e/../../f/g/../h", "/a/f/h");
  check_normalize ("//a//b//..//c//d//..//e//..//..//f//g//..//h", "/a/f/h");
  check_normalize ("../a", NULL);
  check_normalize ("a/../../b", "../b");
  check_normalize ("/../a", "/a");
  check_normalize ("/a/../../b", "/b");
  check_normalize ("./b/./c/.d/..e/./f", "b/c/.d/..e/f");
  check_normalize ("/b/././././e", "/b/e");
  check_normalize (".", "");    /* maybe the result should be "."? */
  check_normalize ("/.", "/");
  check_normalize ("./", "");   /* maybe the result should be "."? */
  check_normalize ("/a/b/..", "/a");
  check_normalize ("/a/b/../..", "/");
  check_normalize ("/a/b/../../..", "/");
  check_normalize ("a/b/..", "a");
  check_normalize ("a/b/../..", "");
  check_normalize ("a/b/../../..", "..");

  check_combine_and_normalize ("/path1/file1", "/path2/file2", "/path2/file2");
  check_combine_and_normalize ("path1/file1", "/path2/file2", "/path2/file2");
  check_combine_and_normalize ("/path1/file1", "path2/file2", "/path1/path2/file2");
  check_combine_and_normalize ("/path1", "/path2", "/path2");
  check_combine_and_normalize ("path1", "/path2", "/path2");
  check_combine_and_normalize ("/path1", "path2", "/path2");
  check_combine_and_normalize ("/path1/file1/../u", "path2/x/../y/z/../a/b/..", "/path1/path2/y/a");
  check_combine_and_normalize ("/path1/file1", "/path2//file2", "/path2/file2");
  check_combine_and_normalize ("/path1/file1", "/..", "/");
  check_combine_and_normalize ("/path1/file1", "../x", "/x");
  check_combine_and_normalize ("/path1/file1", "../../../x", "/x");
  check_combine_and_normalize ("/path1/file1", "/.x/..x/...x/x", "/.x/..x/...x/x");

  return (0);
}
#endif