/* Copyright (C) 2001 Free Software Foundation, Inc.
   A wrapper for mktime function allowing to specify the timezone.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

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

#include <errno.h>
#include <netdb.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>

#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>

#ifdef HAVE_STRINGS_H
#include <strings.h>
#endif

#include <mailutils/error.h>
#include <mailutils/iterator.h>
#include <mailutils/mutil.h>

/* convert a sequence of hex characters into an integer */

unsigned long
mu_hex2ul (char hex)
{
  if (hex >= '0' && hex <= '9')
   return hex - '0';

  if (hex >= 'a' && hex <= 'z')
    return hex - 'a';

  if (hex >= 'A' && hex <= 'Z')
    return hex - 'A';

  return -1;
}

size_t
mu_hexstr2ul (unsigned long *ul, const char *hex, size_t len)
{
  size_t r;

  *ul = 0;

  for (r = 0; r < len; r++)
    {
      unsigned long v = mu_hex2ul (hex[r]);

      if (v == (unsigned long)-1)
	return r;

      *ul = *ul * 16 + v;
    }
  return r;
}

/* Convert struct tm into time_t, taking into account timezone offset.

 mktime() always treats tm as if it was localtime, so convert it
 to UTC, then adjust by the tm's real timezone, if it is known.

 NOTE: 1. mktime converts localtime struct tm to *time_t in UTC*
       2. adding mu_utc_offset() compensates for the localtime
          corrections in mktime(), i.e. it yields the time_t in
	  the current zone of struct tm.
       3. finally, subtracting TZ offset yields the UTC.
*/
time_t
mu_tm2time (struct tm *timeptr, mu_timezone* tz)
{
  int offset = tz ? tz->utc_offset : 0;

  return mktime (timeptr) + mu_utc_offset () - offset;
}

/* Convert time 0 at UTC to our localtime, that tells us the offset
   of our current timezone from UTC. */
time_t
mu_utc_offset (void)
{
  time_t t = 0;
  struct tm* tm = gmtime (&t);

  return - mktime (tm);
}

static const char *months[] =
{
  "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", NULL
};

static const char *wdays[] =
{
  "Sun", "Mon", "Teu", "Wed", "Thr", "Fri", "Sat", NULL
};

int
mu_parse_imap_date_time (const char **p, struct tm *tm, mu_timezone *tz)
{
  int year, mon, day, hour, min, sec;
  char zone[6] = "+0000";	/* ( "+" / "-" ) hhmm */
  char month[5] = "";
  int hh = 0;
  int mm = 0;
  int sign = 1;
  int scanned = 0, scanned3;
  int i;
  int tzoffset;

  day = mon = year = hour = min = sec = 0;

  memset (tm, 0, sizeof (*tm));

  switch (sscanf (*p,
		  "%2d-%3s-%4d%n %2d:%2d:%2d %5s%n",
		  &day, month, &year, &scanned3, &hour, &min, &sec, zone,
		  &scanned))
    {
    case 3:
      scanned = scanned3;
      break;
    case 7:
      break;
    default:
      return -1;
    }

  tm->tm_sec = sec;
  tm->tm_min = min;
  tm->tm_hour = hour;
  tm->tm_mday = day;

  for (i = 0; i < 12; i++)
    {
      if (strncasecmp (month, months[i], 3) == 0)
	{
	  mon = i;
	  break;
	}
    }
  tm->tm_mon = mon;
  tm->tm_year = (year > 1900) ? year - 1900 : year;
  tm->tm_yday = 0;		/* unknown. */
  tm->tm_wday = 0;		/* unknown. */
#if HAVE_TM_ISDST
  tm->tm_isdst = -1;		/* unknown. */
#endif

  hh = (zone[1] - '0') * 10 + (zone[2] - '0');
  mm = (zone[3] - '0') * 10 + (zone[4] - '0');
  sign = (zone[0] == '-') ? -1 : +1;
  tzoffset = sign * (hh * 60 * 60 + mm * 60);

#if HAVE_TM_GMTOFFSET
  tm->tm_gmtoffset = tzoffset;
#endif

  if (tz)
    {
      tz->utc_offset = tzoffset;
      tz->tz_name = NULL;
    }

  *p += scanned;

  return 0;
}

/* "ctime" format is: Thu Jul 01 15:58:27 1999, with no trailing \n.  */
int
mu_parse_ctime_date_time (const char **p, struct tm *tm, mu_timezone * tz)
{
  int wday = 0;
  int year = 0;
  int mon = 0;
  int day = 0;
  int hour = 0;
  int min = 0;
  int sec = 0;
  int n = 0;
  int i;
  char weekday[5] = "";
  char month[5] = "";

  if (sscanf (*p, "%3s %3s %2d %2d:%2d:%2d %d%n\n",
	weekday, month, &day, &hour, &min, &sec, &year, &n) != 7)
    return -1;

  *p += n;

  for (i = 0; i < 7; i++)
    {
      if (strncasecmp (weekday, wdays[i], 3) == 0)
	{
	  wday = i;
	  break;
	}
    }

  for (i = 0; i < 12; i++)
    {
      if (strncasecmp (month, months[i], 3) == 0)
	{
	  mon = i;
	  break;
	}
    }

  if (tm)
    {
      memset (tm, 0, sizeof (struct tm));

      tm->tm_sec = sec;
      tm->tm_min = min;
      tm->tm_hour = hour;
      tm->tm_mday = day;
      tm->tm_wday = wday;
      tm->tm_mon = mon;
      tm->tm_year = (year > 1900) ? year - 1900 : year;
#ifdef HAVE_TM_ISDST
      tm->tm_isdst = -1;	/* unknown. */
#endif
    }

  /* ctime has no timezone information, set tz to UTC if they ask. */
  if (tz)
    memset (tz, 0, sizeof (struct mu_timezone));

  return 0;
}

char *
mu_get_homedir (void)
{
  char *homedir = getenv ("HOME");
  if (!homedir)
    {
      struct passwd *pwd;

      pwd = mu_getpwuid (getuid ());
      if (!pwd)
	return NULL;
      homedir = pwd->pw_dir;
    }
  return homedir;
}

char *
mu_getcwd ()
{
  char *ret;
  unsigned path_max;
  char buf[128];

  errno = 0;
  ret = getcwd (buf, sizeof (buf));
  if (ret != NULL)
    return strdup (buf);

  if (errno != ERANGE)
    return NULL;

  path_max = 128;
  path_max += 2;                /* The getcwd docs say to do this. */

  for (;;)
    {
      char *cwd = (char *) malloc (path_max);

      errno = 0;
      ret = getcwd (cwd, path_max);
      if (ret != NULL)
        return ret;
      if (errno != ERANGE)
        {
          int save_errno = errno;
          free (cwd);
          errno = save_errno;
          return NULL;
        }

      free (cwd);

      path_max += path_max / 16;
      path_max += 32;
    }
  /* oops?  */
  return NULL;
}

char *
mu_get_full_path (const char *file)
{
  char *p = NULL;

  if (!file)
    p = mu_getcwd ();
  else if (*file != '/')
    {
      char *cwd = mu_getcwd ();
      if (cwd)
	{
	  p = calloc (strlen (cwd) + 1 + strlen (file) + 1, 1);
	  if (p)
	    sprintf (p, "%s/%s", cwd, file);
	  free (cwd);
	}
    }

  if (!p)
    p = strdup (file);
  return p;
}

/* NOTE: Allocates Memory.  */
/* Expand: ~ --> /home/user and to ~guest --> /home/guest.  */
char *
mu_tilde_expansion (const char *ref, const char *delim, const char *homedir)
{
  char *p = strdup (ref);

  if (*p == '~')
    {
      p++;
      if (*p == delim[0] || *p == '\0')
        {
	  char *s;
	  if (!homedir)
	    {
	      homedir = mu_get_homedir ();
	      if (!homedir)
		return NULL;
	    }
	  s = calloc (strlen (homedir) + strlen (p) + 1, 1);
          strcpy (s, homedir);
          strcat (s, p);
          free (--p);
          p = s;
        }
      else
        {
          struct passwd *pw;
          char *s = p;
          char *name;
          while (*s && *s != delim[0])
            s++;
          name = calloc (s - p + 1, 1);
          memcpy (name, p, s - p);
          name [s - p] = '\0';
          pw = mu_getpwnam (name);
          free (name);
          if (pw)
            {
              char *buf = calloc (strlen (pw->pw_dir) + strlen (s) + 1, 1);
              strcpy (buf, pw->pw_dir);
              strcat (buf, s);
              free (--p);
              p = buf;
            }
          else
            p--;
        }
    }
  return p;
}

/* Smart strncpy that always add the null and returns the number of bytes
   written.  */
size_t
mu_cpystr (char *dst, const char *src, size_t size)
{
  size_t len = src ? strlen (src) : 0 ;
  if (dst == NULL || size == 0)
    return len;
  if (len >= size)
    len = size - 1;
  memcpy (dst, src, len);
  dst[len] = '\0';
  return len;
}

/* General retrieve stack support: */

void
mu_register_retriever (list_t *pflist, mu_retrieve_fp fun)
{
  if (!*pflist && list_create (pflist))
    return;
  list_append (*pflist, fun);
}

void *
mu_retrieve (list_t flist, void *data)
{
  void *p = NULL;
  iterator_t itr;

  if (iterator_create (&itr, flist) == 0)
    {
      mu_retrieve_fp fun;
      for (iterator_first (itr); !p && !iterator_is_done (itr);
	   iterator_next (itr))
	{
	  iterator_current (itr, (void **)&fun);
	  p = (*fun) (data);
	}

      iterator_destroy (&itr);
    }
  return p;
}

/* getpwd support: */

static list_t _app_getpwnam = NULL;

void
mu_register_getpwnam (struct passwd *(*fun) __P((const char *)))
{
  mu_register_retriever (&_app_getpwnam, (mu_retrieve_fp)fun);
}

struct passwd *
mu_getpwnam (const char *name)
{
  struct passwd *p = getpwnam (name);
  return p ? p : mu_retrieve (_app_getpwnam, (void*) name);
}

/* getpwuid support: */

static list_t _app_getpwuid = NULL;

void
mu_register_getpwuid (struct passwd *(*fun) __P((uid_t)))
{
  mu_register_retriever (&_app_getpwuid, (mu_retrieve_fp)fun);
}

struct passwd *
mu_getpwuid (uid_t uid)
{
  struct passwd *p = getpwuid (uid);
  return p ? p : mu_retrieve (_app_getpwuid, &uid);
}

/* Virtual domains */

int mu_virtual_domain;

#ifdef USE_VIRTUAL_DOMAINS

struct passwd *
getpwnam_virtual (const char *u)
{
  struct passwd *pw = NULL;
  FILE *pfile;
  size_t i = 0, len = strlen (u), delim = 0;
  char *filename;

  mu_virtual_domain = 0;
  for (i = 0; i < len && delim == 0; i++)
    if (u[i] == '!' || u[i] == ':' || u[i] == '@')
      delim = i;

  if (delim == 0)
    return NULL;

  filename = malloc (strlen (SITE_VIRTUAL_PWDDIR) +
		     strlen (&u[delim + 1]) + 2 /* slash and null byte */);
  if (filename == NULL)
    return NULL;

  sprintf (filename, "%s/%s", SITE_VIRTUAL_PWDDIR, &u[delim + 1]);
  pfile = fopen (filename, "r");
  free (filename);

  if (pfile)
    while ((pw = fgetpwent (pfile)) != NULL)
      {
	if (strlen (pw->pw_name) == delim && !strncmp (u, pw->pw_name, delim))
	  {
	    mu_virtual_domain = 1;
	    break;
	  }
      }

  return pw;
}

#endif

char *
mu_get_user_email (char *name)
{
  char hostname[256];
  struct hostent *hp;
  char *domainpart;
  char *email;

  if (!name)
    {
      struct passwd *pw = getpwuid (getuid ());
      if (!pw)
	{
	  errno = EINVAL;
	  return NULL;
	}
      name = pw->pw_name;
    }

  gethostname (hostname, sizeof hostname);
  hostname[sizeof (hostname)-1] = 0;

  if ((hp = gethostbyname (hostname)))
    domainpart = hp->h_name;
  else
    domainpart = hostname;
  email = malloc (strlen (name) + strlen (domainpart) + 2);
  if (!email)
    {
      errno = ENOMEM;
      return NULL;
    }
  sprintf (email, "%s@%s", name, domainpart);
  return email;
}

/* mu_normalize_path: convert pathname containig relative paths specs (../)
   into an equivalent absolute path. Strip trailing delimiter if present,
   unless it is the only character left. E.g.:

         /home/user/../smith   -->   /home/smith
	 /home/user/../..      -->   /

   FIXME: delim is superfluous. The function deals with unix filesystem
   paths, so delim should be always "/" */
char *
mu_normalize_path (char *path, const char *delim)
{
  int len;
  char *p;

  if (!path)
    return path;

  len = strlen (path);

  /* Empty string is returned as is */
  if (len == 0)
    return path;

  /* delete trailing delimiter if any */
  if (len && path[len-1] == delim[0])
    path[len-1] = 0;

  /* Eliminate any /../ */
  for (p = strchr (path, '.'); p; p = strchr (p, '.'))
    {
      if (p > path && p[-1] == delim[0])
	{
	  if (p[1] == '.' && (p[2] == 0 || p[2] == delim[0]))
	    /* found */
	    {
	      char *q, *s;

	      /* Find previous delimiter */
	      for (q = p-2; *q != delim[0] && q >= path; q--)
		;

	      if (q < path)
		break;
	      /* Copy stuff */
	      s = p + 2;
	      p = q;
	      while ((*q++ = *s++))
		;
	      continue;
	    }
	}

      p++;
    }

  if (path[0] == 0)
    {
      path[0] = delim[0];
      path[1] = 0;
    }

  return path;
}

char *
mu_normalize_maildir (const char *dir)
{
  int len = strlen (dir);
  if (dir[len-1] == '/')
    return strdup (dir);
  else if (strncasecmp (dir, "mbox:", 5) == 0 && dir[len-1] == '=')
    {
      if (len > 5 && strcmp (dir + len - 5, "user=") == 0)
	return strdup (dir);
      else
	return NULL;
    }
  else
    {
      char *p = malloc (strlen (dir) + 2);
      strcat (strcpy (p, dir), "/");
      return p;
    }
}

/* Create and open a temporary file. Be vary careful about it, since we
   may be running with extra privilege i.e setgid().
   Returns file descriptor of the open file.
   If namep is not NULL, the pointer to the malloced file name will
   be stored there. Otherwise, the file is unlinked right after open,
   i.e. it will disappear after close(fd). */

#ifndef P_tmpdir
# define P_tmpdir "/tmp"
#endif

int
mu_tempfile (const char *tmpdir, char **namep)
{
  char *filename;
  int fd;

  if (!tmpdir)
    tmpdir = (getenv ("TMPDIR")) ? getenv ("TMPDIR") : P_tmpdir;

  filename = malloc (strlen (tmpdir) + /*'/'*/1 + /* "muXXXXXX" */8 + 1);
  if (!filename)
    return -1;
  sprintf (filename, "%s/muXXXXXX", tmpdir);

#ifdef HAVE_MKSTEMP
  {
    int save_mask = umask (077);
    fd = mkstemp (filename);
    umask (save_mask);
  }
#else
  if (mktemp (filename))
    fd = open (filename, O_CREAT|O_EXCL|O_RDWR, 0600);
  else
    fd = -1;
#endif

  if (fd == -1)
    {
      mu_error ("Can not open temporary file: %s", strerror(errno));
      free (filename);
      return -1;
    }

  if (namep)
    *namep = filename;
  else
    {
      unlink (filename);
      free (filename);
    }

  return fd;
}

/* See Advanced Programming in the UNIX Environment, Stevens,
 * program  10.20 for the rational for the signal handling. I
 * had to look it up, so if somebody else is curious, thats where
 * to find it.
 */
int mu_spawnvp (const char* prog, const char* const av_[], int* stat)
{
  pid_t pid;
  int err = 0;
  int progstat;
  struct sigaction ignore;
  struct sigaction saveintr;
  struct sigaction savequit;
  sigset_t chldmask;
  sigset_t savemask;
  char** av = (char**) av_;

  if (!prog || !av)
    return EINVAL;

  ignore.sa_handler = SIG_IGN;	/* ignore SIGINT and SIGQUIT */
  ignore.sa_flags = 0;
  sigemptyset (&ignore.sa_mask);

  if (sigaction (SIGINT, &ignore, &saveintr) < 0)
    return errno;
  if (sigaction (SIGQUIT, &ignore, &savequit) < 0)
    return errno;

  sigemptyset (&chldmask);	/* now block SIGCHLD */
  sigaddset (&chldmask, SIGCHLD);

  if (sigprocmask (SIG_BLOCK, &chldmask, &savemask) < 0)
    return errno;

#ifdef HAVE_VFORK
  pid = vfork ();
#else
  pid = fork ();
#endif

  if (pid < 0)
    {
      err = errno;
    }
  else if (pid == 0)
    {				/* child */
      /* restore previous signal actions & reset signal mask */
      sigaction (SIGINT, &saveintr, NULL);
      sigaction (SIGQUIT, &savequit, NULL);
      sigprocmask (SIG_SETMASK, &savemask, NULL);

      execvp (av[0], av);
#ifdef HAVE__EXIT      
      _exit (127);		/* exec error */
#else
      exit (127);
#endif
    }
  else
    {				/* parent */
      while (waitpid (pid, &progstat, 0) < 0)
	if (errno != EINTR)
	  {
	    err = errno;	/* error other than EINTR from waitpid() */
	    break;
	  }
      if(err == 0 && stat)
	*stat = progstat;
    }

  /* restore previous signal actions & reset signal mask */
  /* preserve first error number, but still try and reset the signals */
  if (sigaction (SIGINT, &saveintr, NULL) < 0)
    err = err ? err : errno;
  if (sigaction (SIGQUIT, &savequit, NULL) < 0)
    err = err ? err : errno;
  if (sigprocmask (SIG_SETMASK, &savemask, NULL) < 0)
    err = err ? err : errno;

  return err;
}