/* GNU mailutils - a suite of utilities for electronic mail
   Copyright (C) 1999, 2001 Free Software Foundation, Inc.

   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 2, 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, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "imap4d.h"

static int add2set __P ((size_t **, int *, unsigned long));
static const char *sc2string __P ((int));

/* Get the next space/CR/NL separated word, some words are between double
   quotes, strtok() can not handle it.  */
char *
util_getword (char *s, char **save)
{
  return util_getitem (s, " \r\n", save);
}

/* Take care of words between double quotes.  */
char *
util_getitem (char *s, const char *delim, char **save)
{
  {
    char *p;
    if ((p = s) || (p = *save))
      {
	while (isspace ((unsigned)*p))
	  p++;
	if (*p == '"')
	  {
	    s = p;
	    p++;
	    while (*p && *p != '"')
	      p++;
	    if (*p == '"')
		p++;
	    *save = (*p) ? p + 1 : p;
	    *p = '\0';
	    return s;
	  }
      }
  }
  return strtok_r (s, delim, save);
}

/* Stop a the first char that IMAP4 represent as a special characters.  */
int
util_token (char *buf, size_t len, char **ptr)
{
  char *start = *ptr;
  size_t i;
  /* Skip leading space.  */
  while (**ptr && **ptr == ' ')
    (*ptr)++;

  /* Break the string by token, i.e when we reconize IMAP special
     atoms we stop and send it.  */
  for (i = 1; **ptr && i < len; (*ptr)++, buf++, i++)
    {
      if (**ptr == ' ' || **ptr == '.'
          || **ptr == '(' || **ptr == ')'
          || **ptr == '[' || **ptr == ']'
          || **ptr == '<' || **ptr  == '>'
	  || **ptr == '\r' || **ptr == '\n')
        {
          /* Advance.  */
          if (start == (*ptr))
            (*ptr)++;
          break;
        }
      *buf = **ptr;
  }
  *buf = '\0';
  /* Skip trailing space.  */
  while (**ptr && **ptr == ' ')
    (*ptr)++;
  return  *ptr - start;
}

/* Remove the surrounding double quotes.  */
/* FIXME:  Check if the quote was escaped and ignore it.  */
void
util_unquote (char **ptr)
{
  char *s = *ptr;
  size_t len;
  if (s && *s == '"' && (len = strlen (s)) > 1 && s[len - 1] == '"')
    {
      char *p = ++s;
      while (*p && *p != '"')
        p++;
      if (*p == '"')
        *p = '\0';
    }
  *ptr = s;
}

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

/* Get the absolute path.  */
/* NOTE: Path is allocated and must be free()d by the caller.  */
char *
util_getfullpath (char *name, const char *delim)
{
  char *p = util_tilde_expansion (name, delim);
  if (*p != delim[0])
    {
      char *s = calloc (strlen (homedir) + strlen (delim) + strlen (p) + 1, 1);
      sprintf (s, "%s%s%s", homedir, delim, p);
      free (p);
      p = s;
    }
  return mu_normalize_path (p, delim);
}

/* Return in set an allocated array contain (n) numbers, for imap messsage set
   set ::= sequence_num / (sequence_num ":" sequence_num) / (set "," set)
   sequence_num    ::= nz_number / "*"
   ;; * is the largest number in use.  For message
   ;; sequence numbers, it is the number of messages
   ;; in the mailbox.  For unique identifiers, it is
   ;; the unique identifier of the last message in
   ;; the mailbox.
   nz_number       ::= digit_nz *digit

   FIXME: The algo below is to relaxe, things like <,,,> or <:12> or <20:10>
   will not generate an error.  */
int
util_msgset (char *s, size_t **set, int *n, int isuid)
{
  unsigned long val = 0;
  unsigned long low = 0;
  int done = 0;
  int status = 0;
  size_t max = 0;

  status = mailbox_messages_count (mbox, &max);
  if (status != 0)
    return status;
  /* If it is a uid sequence, override max with the UID.  */
  if (isuid)
    {
      message_t msg = NULL;
      mailbox_get_message (mbox, max, &msg);
      message_get_uid (msg, &max);
    }

  *n = 0;
  *set = NULL;
  while (*s)
    {
      switch (*s)
	{
	  /* isdigit */
	case '0': case '1': case '2': case '3': case '4':
	case '5': case '6': case '7': case '8': case '9':
	  {
	    errno = 0;
	    val = strtoul (s, &s, 10);
	    if (val == ULONG_MAX && errno == ERANGE)
	      {
		if (*set)
		  free (*set);
		*n = 0;
		return EINVAL;
	      }
	    if (low)
	      {
		/* Reverse it. */
		if (low > val)
		  {
		    long tmp = low;
		    tmp -= 2;
		    if (tmp < 0 || val == 0)
		      {
			free (*set);
			*n = 0;
			return EINVAL;
		      }
		    low = val;
		    val = tmp;
		  }
		for (;low && low <= val; low++)
		  {
		    status = add2set (set, n, low);
		    if (status != 0)
		      return status;
		  }
		low = 0;
	      }
	    else
	      {
		status = add2set (set, n, val);
		if (status != 0)
		  return status;
	      }
	    break;
	  }

	  /* A pair of numbers separated by a ':' character indicates a
	     contiguous set of mesages ranging from the first number to the
	     second:
	     3:5  --> 3 4 5
	  */
	case ':':
	  low = val + 1;
	  s++;
	  break;

	  /* As a convenience. '*' is provided to refer to the highest message
	     number int the mailbox:
	     5:*  --> 5 6 7 8
	  */
	case '*':
	  {
	    val = max;
	    s++;
	    status = add2set (set, n, val);
	    if (status != 0)
	      return status;
	  }
	  break;

	  /* IMAP also allows a set of noncontiguous numbers to be specified
	     with the ',' character:
	     1,3,5,7  --> 1 3 5 7
	  */
	case ',':
	  s++;
	  break;

	default:
	  done = 1;
	  if (*set)
	    free (*set);
	  *n = 0;
	  return EINVAL;

	} /* switch */

      if (done)
	break;
    } /* while */

  if (low)
    {
      /* Reverse it. */
      if (low > val)
	{
	  long tmp = low;
	  tmp -= 2;
	  if (tmp < 0 || val == 0)
	    {
	      free (set);
	      *n = 0;
	      return EINVAL;
	    }
	  low = val;
	  val = tmp;
	}
      for (;low && low <= val; low++)
	{
	  status = add2set (set, n, low);
	  if (status != 0)
	    return status;
	}
    }
  return 0;
}

/* Use vfprintf for the dirty work.  */
int
util_send (const char *format, ...)
{
  int status;
  va_list ap;
  va_start (ap, format);
  status = vfprintf (ofile, format, ap);
  va_end (ap);
  return status;
}

/* Send NIL if empty string, change the quoted string to a literal if the
   string contains: double quotes, CR, LF, and '/'.  CR, LF will be change
   to spaces.  */
int
util_send_qstring (const char *buffer)
{
  if (buffer == NULL || *buffer == '\0')
    return util_send ("NIL");
  if (strchr (buffer, '"') || strchr (buffer, '\r') || strchr (buffer, '\n')
      || strchr (buffer, '\\'))
    {
      char *s;
      int ret;
      char *b = strdup (buffer);
      while ((s = strchr (b, '\n')) || (s = strchr (b, '\r')))
	*s = ' ';
      ret = util_send_literal (b);
      free (b);
      return ret;
    }
  return util_send ("\"%s\"", buffer);
}

int
util_send_literal (const char *buffer)
{
  return util_send ("{%u}\r\n%s", strlen (buffer), buffer);
}

/* Send an unsolicited response.  */
int
util_out (int rc, const char *format, ...)
{
  char *buf = NULL;
  int status;
  va_list ap;
  asprintf (&buf, "* %s%s\r\n", sc2string (rc), format);
  va_start (ap, format);
  status = vfprintf (ofile, buf, ap);
  va_end (ap);
  free (buf);
  return status;
}

/* Send the tag response and reset the state.  */
int
util_finish (struct imap4d_command *command, int rc, const char *format, ...)
{
  char *buf = NULL;
  int new_state;
  int status;
  va_list ap;

  asprintf (&buf, "%s %s%s %s\r\n", command->tag, sc2string (rc),
	    command->name, format);

  va_start (ap, format);
  status = vfprintf (ofile, buf, ap);
  va_end (ap);
  free (buf);
  /* Reset the state.  */
  new_state = (rc == RESP_OK) ? command->success : command->failure;
  if (new_state != STATE_NONE)
    state = new_state;
  return status;
}

/* Clients are allowed to send literal string to the servers.  this
   mean that it can me everywhere where a string is allowed.
   A literal is a sequence of zero or more octets (including CR and LF)
   prefix-quoted with an octet count in the form of an open brace ("{"),
   the number of octets, close brace ("}"), and CRLF.
 */
char *
imap4d_readline (FILE *fp)
{
  char buffer[512];
  size_t len;
  long number = 0;
  size_t total = 0;
  char *line = malloc (1);

  if (!line)
    imap4d_bye (ERR_NO_MEM);

  line[0] = '\0'; /* start with a empty string.  */
  do
    {
      alarm (daemon_param.timeout);
      if (fgets (buffer, sizeof (buffer), fp) == NULL)
	{
	  imap4d_bye (ERR_NO_OFILE); /* Logout.  */
	}
      alarm (0);

      len = strlen (buffer);
      /* If we were in a litteral substract. We have to do it here since the CR
	 is part of the count in a literal.  */
      if (number)
        number -= len;

      /* Remove CR.  */
      if (len > 1 && buffer[len - 1] == '\n')
	{
	  if (buffer[len - 2] == '\r')
	    {
	      buffer[len - 2] = '\n';
	      buffer[len - 1] = '\0';
	    }
	}
      line = realloc (line, total + len + 1);
      if (!line)
	imap4d_bye (ERR_NO_MEM);
      strcat (line, buffer);

      total = strlen (line);

      /* I observe some client requesting long FETCH operations since, I did
	 not see any limit in the command length in the RFC, catch things
	 here.  */
      /* Check that we do have a terminated NL line and we are not retrieving
	 a literal. If we don't continue the read.  */
      if (number <= 0 && total && line[total - 1] != '\n')
	continue;

      /* Check if the client try to send a literal and make sure we are not
	 already retrieving a literal.  */
      if (number <= 0 && len > 2)
        {
          size_t n = total - 1; /* C arrays are 0-based.  */
	  /* A literal is this "{number}\n".  The CR is already strip.  */
          if (line[n] == '\n' && line[n - 1] == '}')
            {
	      /* Search for the matching bracket.  */
              while (n && line[n] != '{') n--;
              if (line [n] == '{')
                {
                  char *sp = NULL;
		  /* Truncate where the literal number was.  */
                  line[n] = '\0';
                  number = strtoul (line + n + 1, &sp, 10);
		  /* Client can ask for non synchronise literal,
		   if a '+' is append to the octet count. */
                  if (*sp != '+')
                    util_send ("+ GO AHEAD\r\n");
                }
            }
        }
    }
  while (number > 0 || (total && line[total - 1] != '\n'));
  /* syslog (LOG_INFO, "readline: %s", line); */
  return line;
}

char *
imap4d_readline_ex (FILE *fp)
{
  int len;
  char *s = imap4d_readline (fp);

  if (s && (len = strlen (s)) > 0 && s[len-1] == '\n')
      s[len-1] = 0;
  return s;
} 
      
int
util_do_command (char *prompt)
{
  char *sp = NULL, *tag, *cmd;
  struct imap4d_command *command;
  static struct imap4d_command nullcommand;
  size_t len;

  tag = util_getword (prompt, &sp);
  cmd = util_getword (NULL, &sp);
  if (!tag)
    {
      nullcommand.name = "";
      nullcommand.tag = (char *)"*";
      return util_finish (&nullcommand, RESP_BAD, "Null command");
    }
  else if (!cmd)
    {
      nullcommand.name = "";
      nullcommand.tag = tag;
      return util_finish (&nullcommand, RESP_BAD, "Missing arguments");
    }

  util_start (tag);

  command = util_getcommand (cmd, imap4d_command_table);
  if (command == NULL)
    {
      nullcommand.name = "";
      nullcommand.tag = tag;
      return util_finish (&nullcommand, RESP_BAD,  "Invalid command");
    }

  command->tag = tag;
  len = strlen (sp);
  if (len  && sp[len - 1] == '\n')
    sp[len - 1] = '\0';
  return command->func (command, sp);
}

int
util_upper (char *s)
{
  if (!s)
    return 0;
  for (; *s; s++)
    *s = toupper ((unsigned)*s);
  return 0;
}

/* FIXME:  What is this for?  */
int
util_start (char *tag)
{
  (void)tag;
  return 0;
}

/* FIXME:  What is this for?  */
int
util_getstate (void)
{
  return STATE_NONAUTH;
}

struct imap4d_command *
util_getcommand (char *cmd, struct imap4d_command command_table[])
{
  size_t i, len = strlen (cmd);

  for (i = 0; command_table[i].name != 0; i++)
    {
      if (strlen (command_table[i].name) == len &&
	  !strcasecmp (command_table[i].name, cmd))
	return &command_table[i];
    }
  return NULL;
}

/* Status Code to String.  */
static const char *
sc2string (int rc)
{
  switch (rc)
    {
    case RESP_OK:
      return "OK ";

    case RESP_BAD:
      return "BAD ";

    case RESP_NO:
      return "NO ";

    case RESP_BYE:
      return "BYE ";
    }
  return "";
}

static int
add2set (size_t **set, int *n, unsigned long val)
{
  size_t *tmp;
  tmp = realloc (*set, (*n + 1) * sizeof (**set));
  if (tmp == NULL)
    {
      if (*set)
	free (*set);
      *n = 0;
      return ENOMEM;
    }
  *set = tmp;
  (*set)[*n] = val;
  (*n)++;
  return 0;
}

int
util_parse_internal_date0 (char *date, time_t *timep, char **endp)
{
  struct tm tm;
  mu_timezone tz;
  time_t time;
  char **datep = &date;

  if (mu_parse_imap_date_time((const char **)datep, &tm, &tz))
    return 1;

  time = mu_tm2time (&tm, &tz);
  if (time == (time_t) -1)
    return 2;

  *timep = time;
  if (endp)
    *endp = *datep;
  return 0;
}

int
util_parse_internal_date (char *date, time_t *timep)
{
  return util_parse_internal_date0 (date, timep, NULL);
}


int
util_parse_822_date (char *date, time_t *timep)
{
  struct tm tm;
  mu_timezone tz;
  const char* p = date;

  if (parse822_date_time(&p, date+strlen(date), &tm, &tz) == 0)
    {
      *timep = mu_tm2time (&tm, &tz);
      return 0;
    }
  return 1;
}

int
util_parse_ctime_date (const char *date, time_t *timep)
{
  struct tm tm;
  mu_timezone tz;

  if (mu_parse_ctime_date_time(&date, &tm, &tz) == 0)
    {
      *timep = mu_tm2time (&tm, &tz);
      return 0;
    }
  return 1;
}

/* Return the first ocurrence of NEEDLE in HAYSTACK. Case insensitive
   comparison */
char *
util_strcasestr (const char *haystack, const char *needle)
{
  register char *needle_end = strchr(needle, '\0');
  register char *haystack_end = strchr(haystack, '\0');
  register size_t needle_len = needle_end - needle;
  register size_t needle_last = needle_len - 1;
  register const char *begin;

  if (needle_len == 0)
    return (char *) haystack_end;

  if ((size_t) (haystack_end - haystack) < needle_len)
    return NULL;

  for (begin = &haystack[needle_last]; begin < haystack_end; ++begin)
    {
      register const char *n = &needle[needle_last];
      register const char *h = begin;

      do
	if (tolower(*h) != tolower(*n))
	  goto loop;		/* continue for loop */
      while (--n >= needle && --h >= haystack);

      return (char *) h;

    loop:;
    }

  return NULL;
}

struct
{
  char *name;
  int flag;
} _imap4d_attrlist[] = {
  { "\\Answered", MU_ATTRIBUTE_ANSWERED },
  { "\\Flagged",  MU_ATTRIBUTE_FLAGGED },
  { "\\Deleted", MU_ATTRIBUTE_DELETED },
  { "\\Draft", MU_ATTRIBUTE_DRAFT },
  { "\\Seen", MU_ATTRIBUTE_SEEN },
  { "\\Recent", MU_ATTRIBUTE_RECENT },
};

#define NATTR sizeof(_imap4d_attrlist)/sizeof(_imap4d_attrlist[0])

int _imap4d_nattr = NATTR;

int
util_attribute_to_type (const char *item, int *type)
{
  int i;
  for (i = 0; i < _imap4d_nattr; i++)
    if (strcasecmp (item, _imap4d_attrlist[i].name) == 0)
      {
	*type = _imap4d_attrlist[i].flag;
	return 0;
      }
  return 1;
}

int
util_type_to_attribute (int type, char **attr_str)
{
  *attr_str = NULL;
  if (type == MU_ATTRIBUTE_RECENT)
    *attr_str = strdup("\\Recent");
  else
    {
      char *attr_list[NATTR];
      int nattr = 0;
      int i;
      size_t len = 0;

      for (i = 0; i < _imap4d_nattr; i++)
	if (type & _imap4d_attrlist[i].flag)
	  {
	    attr_list[nattr++] = _imap4d_attrlist[i].name;
	    len += 1 + strlen(_imap4d_attrlist[i].name);
	  }

      *attr_str = malloc(len+1);
      (*attr_str)[0] = 0;
      if (*attr_str)
	{
	  for (i = 0; i < nattr; i++)
	    {
	      strcat(*attr_str, attr_list[i]);
	      if (i != nattr-1)
		strcat(*attr_str, " ");
	    }
	}
    }

  if (!*attr_str)
    imap4d_bye (ERR_NO_MEM);
  return 0;
}

int
util_parse_attributes(char *items, char **save, int *flags)
{
  int rc = 0;

  *flags = 0;
  while (*items)
    {
      int type = 0;
      char item[64] = "";

      util_token (item, sizeof (item), &items);
      if (!util_attribute_to_type (item, &type))
	*flags |= type;
      /*FIXME: else? */

      if (*items == ')')
	{
	  items++;
	  rc = 0;
	  break;
	}
    }

  *save = items;
  return rc;
}

int
util_base64_encode (const unsigned char *input, size_t input_len,
		    unsigned char **output, size_t *output_len)
{
  static char b64tab[] =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  size_t olen = 4 * (input_len + 2) / 3;
  unsigned char *out = malloc (olen);
  
  if (!out)
    return 1;
  *output = out;
  while (input_len >= 3)
    {
      *out++ = b64tab[input[0] >> 2];
      *out++ = b64tab[((input[0] << 4) & 0x30) | (input[1] >> 4)];
      *out++ = b64tab[((input[1] << 2) & 0x3c) | (input[2] >> 6)];
      *out++ = b64tab[input[2] & 0x3f];
      olen  -= 4;
      input_len -= 3;
      input += 3;
    }

  if (input_len > 0)
    {
      unsigned char c = (input[0] << 4) & 0x30;
      *out++ = b64tab[input[0] >> 2];
      if (input_len > 0)
	c |= input[1] >> 4;
      *out++ = b64tab[c];
      *out++ = (input_len < 2) ? '-' : b64tab[(input[1] << 2) & 0x3c];
      *out++ = '=';
    }
  *output_len = out - *output;
  return 0;
}

int
util_base64_decode (const unsigned char *input, size_t input_len,
		    unsigned char **output, size_t *output_len)
{
  static int b64val[128] = {
    -1, -1, -1, -1, -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1, 
    -1, -1, -1, -1, -1, -1, -1, -1,  -1, -1, -1, -1, -1, -1, -1, -1, 
    -1, -1, -1, -1, -1, -1, -1, -1,  -1, -1, -1, 62, -1, -1, -1, 63, 
    52, 53, 54, 55, 56, 57, 58, 59,  60, 61, -1, -1, -1, -1, -1, -1, 
    -1,  0,  1,  2,  3,  4,  5,  6,   7,  8,  9, 10, 11, 12, 13, 14, 
    15, 16, 17, 18, 19, 20, 21, 22,  23, 24, 25, -1, -1, -1, -1, -1, 
    -1, 26, 27, 28, 29, 30, 31, 32,  33, 34, 35, 36, 37, 38, 39, 40, 
    41, 42, 43, 44, 45, 46, 47, 48,  49, 50, 51, -1, -1, -1, -1, -1
  };
  int olen = input_len;
  unsigned char *out = malloc (olen);

  if (!out)
    return 1;
  *output = out;
  do
    {
      if (input[0] > 127 || b64val[input[0]] == -1
	  || input[1] > 127 || b64val[input[1]] == -1
	  || input[2] > 127 || ((input[2] != '=') && (b64val[input[2]] == -1))
	  || input[3] > 127 || ((input[3] != '=') && (b64val[input[3]] == -1)))
	return -1;
      *out++ = (b64val[input[0]] << 2) | (b64val[input[1]] >> 4);
      if (input[2] != '=')
	{
	  *out++ = ((b64val[input[1]] << 4) & 0xf0) | (b64val[input[2]] >> 2);
	  if (input[3] != '=')
	    *out++ = ((b64val[input[2]] << 6) & 0xc0) | b64val[input[3]];
	}
      input += 4;
      input_len -= 4;
    }
  while (input_len > 0);
  *output_len = out - *output;
  return 0;
}

char *
util_localname ()
{
  static char *localname;

  if (!localname)
    {
      char *name;
      int name_len = 256;
      int status;
      struct hostent *hp;
      
      name = malloc (name_len);
      while (name
	     && (status = gethostname (name, name_len)) == 0
	     && !memchr (name, 0, name_len))
	{
	  name_len *= 2;
	  name = realloc (name, name_len);
	}
      if (status)
	{
	  syslog (LOG_CRIT, "Can't find out my own hostname");
	  exit (1);
        }

      hp = gethostbyname (name);
      if (hp)
	{
	  struct in_addr inaddr;
	  inaddr.s_addr = *(unsigned int*)hp->h_addr;
	  hp = gethostbyaddr ((const char *)&inaddr,
			      sizeof (struct in_addr), AF_INET);
	  if (hp)
	    {
	      free (name);
	      name = strdup ((char *)hp->h_name);
	    }
	}
      localname = name;
    }
  return localname;
}