/*
 * Copyright (C) 1998 Brandon Long <blong@fiction.net>
 * Copyright (C) 1999 Andrej Gritsenko <andrej@lucky.net>
 * Copyright (C) 2000-2012 Vsevolod Volkov <vvv@mutt.org.ua>
 *
 *     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 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, write to the Free Software
 *     Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#if HAVE_CONFIG_H
#include "config.h"
#endif

#include "mutt.h"
#include "mutt_curses.h"
#include "sort.h"
#include "mx.h"
#include "mime.h"
#include "mailbox.h"
#include "nntp.h"
#include "rfc822.h"
#include "rfc1524.h"
#include "rfc2047.h"
#include "bcache.h"

#if USE_HCACHE
#include "hcache.h"
#endif

#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <dirent.h>
#include <errno.h>

/* Find NNTP_DATA for given newsgroup or add it */
static NNTP_DATA *nntp_data_find (NNTP_SERVER *nserv, const char *group)
{
  NNTP_DATA *nntp_data = hash_find (nserv->groups_hash, group);

  if (!nntp_data)
  {
    /* create NNTP_DATA structure and add it to hash */
    nntp_data = safe_calloc (1, sizeof (NNTP_DATA) + strlen (group) + 1);
    nntp_data->group = (char *)nntp_data + sizeof (NNTP_DATA);
    strcpy (nntp_data->group, group);
    nntp_data->nserv = nserv;
    nntp_data->deleted = 1;
    if (nserv->groups_hash->nelem < nserv->groups_hash->curnelem * 2)
      nserv->groups_hash = hash_resize (nserv->groups_hash,
			   nserv->groups_hash->nelem * 2, 0);
    hash_insert (nserv->groups_hash, nntp_data->group, nntp_data, 0);

    /* add NNTP_DATA to list */
    if (nserv->groups_num >= nserv->groups_max)
    {
      nserv->groups_max *= 2;
      safe_realloc (&nserv->groups_list,
		    nserv->groups_max * sizeof (nntp_data));
    }
    nserv->groups_list[nserv->groups_num++] = nntp_data;
  }
  return nntp_data;
}

/* Remove all temporarily cache files */
void nntp_acache_free (NNTP_DATA *nntp_data)
{
  int i;

  for (i = 0; i < NNTP_ACACHE_LEN; i++)
  {
    if (nntp_data->acache[i].path)
    {
      unlink (nntp_data->acache[i].path);
      FREE (&nntp_data->acache[i].path);
    }
  }
}

/* Free NNTP_DATA, used to destroy hash elements */
void nntp_data_free (void *data)
{
  NNTP_DATA *nntp_data = data;

  if (!nntp_data)
    return;
  nntp_acache_free (nntp_data);
  mutt_bcache_close (&nntp_data->bcache);
  FREE (&nntp_data->newsrc_ent);
  FREE (&nntp_data->desc);
  FREE (&data);
}

/* Unlock and close .newsrc file */
void nntp_newsrc_close (NNTP_SERVER *nserv)
{
  if (!nserv->newsrc_fp)
    return;

  dprint (1, (debugfile, "Unlocking %s\n", nserv->newsrc_file));
  mx_unlock_file (nserv->newsrc_file, fileno (nserv->newsrc_fp), 0);
  safe_fclose (&nserv->newsrc_fp);
}

/* Parse .newsrc file:
 *  0 - not changed
 *  1 - parsed
 * -1 - error */
int nntp_newsrc_parse (NNTP_SERVER *nserv)
{
  unsigned int i;
  char *line;
  struct stat sb;

  /* if file doesn't exist, create it */
  nserv->newsrc_fp = safe_fopen (nserv->newsrc_file, "a");
  safe_fclose (&nserv->newsrc_fp);

  /* open .newsrc */
  nserv->newsrc_fp = safe_fopen (nserv->newsrc_file, "r");
  if (!nserv->newsrc_fp)
  {
    mutt_perror (nserv->newsrc_file);
    mutt_sleep (2);
    return -1;
  }

  /* lock it */
  dprint (1, (debugfile, "Locking %s\n", nserv->newsrc_file));
  if (mx_lock_file (nserv->newsrc_file, fileno (nserv->newsrc_fp), 0, 0, 1))
  {
    safe_fclose (&nserv->newsrc_fp);
    return -1;
  }

  if (stat (nserv->newsrc_file, &sb))
  {
    mutt_perror (nserv->newsrc_file);
    nntp_newsrc_close (nserv);
    mutt_sleep (2);
    return -1;
  }

  if (nserv->size == sb.st_size && nserv->mtime == sb.st_mtime)
    return 0;

  nserv->size = sb.st_size;
  nserv->mtime = sb.st_mtime;
  nserv->newsrc_modified = 1;
  dprint (1, (debugfile, "Parsing %s\n", nserv->newsrc_file));

  /* .newsrc has been externally modified or hasn't been loaded yet */
  for (i = 0; i < nserv->groups_num; i++)
  {
    NNTP_DATA *nntp_data = nserv->groups_list[i];

    if (!nntp_data)
      continue;

    nntp_data->subscribed = 0;
    nntp_data->newsrc_len = 0;
    FREE (&nntp_data->newsrc_ent);
  }

  line = safe_malloc (sb.st_size + 1);
  while (sb.st_size && fgets (line, sb.st_size + 1, nserv->newsrc_fp))
  {
    char *b, *h, *p;
    unsigned int subs = 0, i = 1;
    NNTP_DATA *nntp_data;

    /* find end of newsgroup name */
    p = strpbrk (line, ":!");
    if (!p)
      continue;

    /* ":" - subscribed, "!" - unsubscribed */
    if (*p == ':')
      subs++;
    *p++ = '\0';

    /* get newsgroup data */
    nntp_data = nntp_data_find (nserv, line);
    FREE (&nntp_data->newsrc_ent);

    /* count number of entries */
    b = p;
    while (*b)
      if (*b++ == ',')
	i++;
    nntp_data->newsrc_ent = safe_calloc (i, sizeof (NEWSRC_ENTRY));
    nntp_data->subscribed = subs;

    /* parse entries */
    i = 0;
    while (p)
    {
      b = p;

      /* find end of entry */
      p = strchr (p, ',');
      if (p)
	*p++ = '\0';

      /* first-last or single number */
      h = strchr (b, '-');
      if (h)
	*h++ = '\0';
      else
	h = b;

      if (sscanf (b, ANUM, &nntp_data->newsrc_ent[i].first) == 1 &&
	  sscanf (h, ANUM, &nntp_data->newsrc_ent[i].last) == 1)
	i++;
    }
    if (i == 0)
    {
	nntp_data->newsrc_ent[i].first = 1;
	nntp_data->newsrc_ent[i].last = 0;
	i++;
    }
    if (nntp_data->lastMessage == 0)
      nntp_data->lastMessage = nntp_data->newsrc_ent[i - 1].last;
    nntp_data->newsrc_len = i;
    safe_realloc (&nntp_data->newsrc_ent, i * sizeof (NEWSRC_ENTRY));
    nntp_group_unread_stat (nntp_data);
    dprint (2, (debugfile, "nntp_newsrc_parse: %s\n", nntp_data->group));
  }
  FREE (&line);
  return 1;
}

/* Generate array of .newsrc entries */
void nntp_newsrc_gen_entries (CONTEXT *ctx)
{
  NNTP_DATA *nntp_data = ctx->data;
  anum_t last = 0, first = 1;
  int series, i;
  int save_sort = SORT_ORDER;
  unsigned int entries;

  if (Sort != SORT_ORDER)
  {
    save_sort = Sort;
    Sort = SORT_ORDER;
    mutt_sort_headers (ctx, 0);
  }

  entries = nntp_data->newsrc_len;
  if (!entries)
  {
    entries = 5;
    nntp_data->newsrc_ent = safe_calloc (entries, sizeof (NEWSRC_ENTRY));
  }

  /* Set up to fake initial sequence from 1 to the article before the
   * first article in our list */
  nntp_data->newsrc_len = 0;
  series = 1;
  for (i = 0; i < ctx->msgcount; i++)
  {
    /* search for first unread */
    if (series)
    {
      /* We don't actually check sequential order, since we mark
       * "missing" entries as read/deleted */
      last = NHDR (ctx->hdrs[i])->article_num;
      if (last >= nntp_data->firstMessage && !ctx->hdrs[i]->deleted &&
	  !ctx->hdrs[i]->read)
      {
	if (nntp_data->newsrc_len >= entries)
	{
	  entries *= 2;
	  safe_realloc (&nntp_data->newsrc_ent, entries * sizeof (NEWSRC_ENTRY));
	}
	nntp_data->newsrc_ent[nntp_data->newsrc_len].first = first;
	nntp_data->newsrc_ent[nntp_data->newsrc_len].last = last - 1;
	nntp_data->newsrc_len++;
	series = 0;
      }
    }

    /* search for first read */
    else
    {
      if (ctx->hdrs[i]->deleted || ctx->hdrs[i]->read)
      {
	first = last + 1;
	series = 1;
      }
      last = NHDR (ctx->hdrs[i])->article_num;
    }
  }

  if (series && first <= nntp_data->lastLoaded)
  {
    if (nntp_data->newsrc_len >= entries)
    {
      entries++;
      safe_realloc (&nntp_data->newsrc_ent, entries * sizeof (NEWSRC_ENTRY));
    }
    nntp_data->newsrc_ent[nntp_data->newsrc_len].first = first;
    nntp_data->newsrc_ent[nntp_data->newsrc_len].last = nntp_data->lastLoaded;
    nntp_data->newsrc_len++;
  }
  safe_realloc (&nntp_data->newsrc_ent,
		nntp_data->newsrc_len * sizeof (NEWSRC_ENTRY));

  if (save_sort != Sort)
  {
    Sort = save_sort;
    mutt_sort_headers (ctx, 0);
  }
}

/* Update file with new contents */
static int update_file (char *filename, char *buf)
{
  FILE *fp;
  char tmpfile[_POSIX_PATH_MAX];
  int rc = -1;

  while (1)
  {
    snprintf (tmpfile, sizeof (tmpfile), "%s.tmp", filename);
    fp = fopen (tmpfile, "w");
    if (!fp)
    {
      mutt_perror (tmpfile);
      *tmpfile = '\0';
      break;
    }
    if (fputs (buf, fp) == EOF)
    {
      mutt_perror (tmpfile);
      break;
    }
    if (fclose (fp) == EOF)
    {
      mutt_perror (tmpfile);
      fp = NULL;
      break;
    }
    fp = NULL;
    if (rename (tmpfile, filename) < 0)
    {
      mutt_perror (filename);
      break;
    }
    *tmpfile = '\0';
    rc = 0;
    break;
  }
  if (fp)
    fclose (fp);
  if (*tmpfile)
    unlink (tmpfile);
  if (rc)
    mutt_sleep (2);
  return rc;
}

/* Update .newsrc file */
int nntp_newsrc_update (NNTP_SERVER *nserv)
{
  char *buf;
  size_t buflen, off;
  unsigned int i;
  int rc = -1;

  if (!nserv)
    return -1;

  buflen = 10 * LONG_STRING;
  buf = safe_calloc (1, buflen);
  off = 0;

  /* we will generate full newsrc here */
  for (i = 0; i < nserv->groups_num; i++)
  {
    NNTP_DATA *nntp_data = nserv->groups_list[i];
    unsigned int n;

    if (!nntp_data || !nntp_data->newsrc_ent)
      continue;

    /* write newsgroup name */
    if (off + strlen (nntp_data->group) + 3 > buflen)
    {
      buflen *= 2;
      safe_realloc (&buf, buflen);
    }
    snprintf (buf + off, buflen - off, "%s%c ", nntp_data->group,
	      nntp_data->subscribed ? ':' : '!');
    off += strlen (buf + off);

    /* write entries */
    for (n = 0; n < nntp_data->newsrc_len; n++)
    {
      if (off + LONG_STRING > buflen)
      {
	buflen *= 2;
	safe_realloc (&buf, buflen);
      }
      if (n)
	buf[off++] = ',';
      if (nntp_data->newsrc_ent[n].first == nntp_data->newsrc_ent[n].last)
	snprintf (buf + off, buflen - off, "%d", nntp_data->newsrc_ent[n].first);
      else if (nntp_data->newsrc_ent[n].first < nntp_data->newsrc_ent[n].last)
	snprintf (buf + off, buflen - off, "%d-%d",
		  nntp_data->newsrc_ent[n].first, nntp_data->newsrc_ent[n].last);
      off += strlen (buf + off);
    }
    buf[off++] = '\n';
  }
  buf[off] = '\0';

  /* newrc being fully rewritten */
  dprint (1, (debugfile, "Updating %s\n", nserv->newsrc_file));
  if (nserv->newsrc_file && update_file (nserv->newsrc_file, buf) == 0)
  {
    struct stat sb;

    rc = stat (nserv->newsrc_file, &sb);
    if (rc == 0)
    {
      nserv->size = sb.st_size;
      nserv->mtime = sb.st_mtime;
    }
    else
    {
      mutt_perror (nserv->newsrc_file);
      mutt_sleep (2);
    }
  }
  FREE (&buf);
  return rc;
}

/* Make fully qualified cache file name */
static void cache_expand (char *dst, size_t dstlen, ACCOUNT *acct, char *src)
{
  char *c;
  char file[_POSIX_PATH_MAX];

  /* server subdirectory */
  if (acct)
  {
    ciss_url_t url;

    mutt_account_tourl (acct, &url);
    url.path = src;
    url_ciss_tostring (&url, file, sizeof (file), U_PATH);
  }
  else
    strfcpy (file, src ? src : "", sizeof (file));

  snprintf (dst, dstlen, "%s/%s", NewsCacheDir, file);

  /* remove trailing slash */
  c = dst + strlen (dst) - 1;
  if (*c == '/')
    *c = '\0';
  mutt_expand_path (dst, dstlen);
}

/* Make fully qualified url from newsgroup name */
void nntp_expand_path (char *line, size_t len, ACCOUNT *acct)
{
  ciss_url_t url;

  url.path = safe_strdup (line);
  mutt_account_tourl (acct, &url);
  url_ciss_tostring (&url, line, len, 0);
  FREE (&url.path);
}

/* Parse newsgroup */
int nntp_add_group (char *line, void *data)
{
  NNTP_SERVER *nserv = data;
  NNTP_DATA *nntp_data;
  char group[LONG_STRING];
  char desc[HUGE_STRING] = "";
  char mod;
  anum_t first, last;

  if (!nserv || !line)
    return 0;

  if (sscanf (line, "%s " ANUM " " ANUM " %c %[^\n]", group,
	      &last, &first, &mod, desc) < 4)
    return 0;

  nntp_data = nntp_data_find (nserv, group);
  nntp_data->deleted = 0;
  nntp_data->firstMessage = first;
  nntp_data->lastMessage = last;
  nntp_data->allowed = mod == 'y' || mod == 'm' ? 1 : 0;
  mutt_str_replace (&nntp_data->desc, desc);
  if (nntp_data->newsrc_ent || nntp_data->lastCached)
    nntp_group_unread_stat (nntp_data);
  else if (nntp_data->lastMessage &&
	   nntp_data->firstMessage <= nntp_data->lastMessage)
    nntp_data->unread = nntp_data->lastMessage - nntp_data->firstMessage + 1;
  else
    nntp_data->unread = 0;
  return 0;
}

/* Load list of all newsgroups from cache */
static int active_get_cache (NNTP_SERVER *nserv)
{
  char buf[HUGE_STRING];
  char file[_POSIX_PATH_MAX];
  time_t t;
  FILE *fp;

  cache_expand (file, sizeof (file), &nserv->conn->account, ".active");
  dprint (1, (debugfile, "Parsing %s\n", file));
  fp = safe_fopen (file, "r");
  if (!fp)
    return -1;

  if (fgets (buf, sizeof (buf), fp) == NULL ||
      sscanf (buf, "%ld%s", &t, file) != 1 || t == 0)
  {
    fclose (fp);
    return -1;
  }
  nserv->newgroups_time = t;

  mutt_message _("Loading list of groups from cache...");
  while (fgets (buf, sizeof (buf), fp))
    nntp_add_group (buf, nserv);
  nntp_add_group (NULL, NULL);
  fclose (fp);
  mutt_clear_error ();
  return 0;
}

/* Save list of all newsgroups to cache */
int nntp_active_save_cache (NNTP_SERVER *nserv)
{
  char file[_POSIX_PATH_MAX];
  char *buf;
  size_t buflen, off;
  unsigned int i;
  int rc;

  if (!nserv->cacheable)
    return 0;

  buflen = 10 * LONG_STRING;
  buf = safe_calloc (1, buflen);
  snprintf (buf, buflen, "%lu\n", (unsigned long)nserv->newgroups_time);
  off = strlen (buf);

  for (i = 0; i < nserv->groups_num; i++)
  {
    NNTP_DATA *nntp_data = nserv->groups_list[i];

    if (!nntp_data || nntp_data->deleted)
      continue;

    if (off + strlen (nntp_data->group) +
	(nntp_data->desc ? strlen (nntp_data->desc) : 0) + 50 > buflen)
    {
      buflen *= 2;
      safe_realloc (&buf, buflen);
    }
    snprintf (buf + off, buflen - off, "%s %d %d %c%s%s\n", nntp_data->group,
	      nntp_data->lastMessage, nntp_data->firstMessage,
	      nntp_data->allowed ? 'y' : 'n', nntp_data->desc ? " " : "",
	      nntp_data->desc ? nntp_data->desc : "");
    off += strlen (buf + off);
  }

  cache_expand (file, sizeof (file), &nserv->conn->account, ".active");
  dprint (1, (debugfile, "Updating %s\n", file));
  rc = update_file (file, buf);
  FREE (&buf);
  return rc;
}

#ifdef USE_HCACHE
/* Used by mutt_hcache_open() to compose hcache file name */
static int nntp_hcache_namer (const char *path, char *dest, size_t destlen)
{
  return snprintf (dest, destlen, "%s.hcache", path);
}

/* Open newsgroup hcache */
header_cache_t *nntp_hcache_open (NNTP_DATA *nntp_data)
{
  ciss_url_t url;
  char file[_POSIX_PATH_MAX];

  if (!nntp_data->nserv || !nntp_data->nserv->cacheable ||
      !nntp_data->nserv->conn || !nntp_data->group ||
      !(nntp_data->newsrc_ent || nntp_data->subscribed ||
      option (OPTSAVEUNSUB)))
    return NULL;

  mutt_account_tourl (&nntp_data->nserv->conn->account, &url);
  url.path = nntp_data->group;
  url_ciss_tostring (&url, file, sizeof (file), U_PATH);
  return mutt_hcache_open (NewsCacheDir, file, nntp_hcache_namer);
}

/* Remove stale cached headers */
void nntp_hcache_update (NNTP_DATA *nntp_data, header_cache_t *hc)
{
  char buf[16];
  int old = 0;
  void *hdata;
  anum_t first, last, current;

  if (!hc)
    return;

  /* fetch previous values of first and last */
  hdata = mutt_hcache_fetch_raw (hc, "index", strlen);
  if (hdata)
  {
    dprint (2, (debugfile,
		"nntp_hcache_update: mutt_hcache_fetch index: %s\n", hdata));
    if (sscanf (hdata, ANUM " " ANUM, &first, &last) == 2)
    {
      old = 1;
      nntp_data->lastCached = last;

      /* clean removed headers from cache */
      for (current = first; current <= last; current++)
      {
	if (current >= nntp_data->firstMessage &&
	    current <= nntp_data->lastMessage)
	  continue;

	snprintf (buf, sizeof (buf), "%d", current);
	dprint (2, (debugfile,
		    "nntp_hcache_update: mutt_hcache_delete %s\n", buf));
	mutt_hcache_delete (hc, buf, strlen);
      }
    }
  }

  /* store current values of first and last */
  if (!old || nntp_data->firstMessage != first ||
	      nntp_data->lastMessage != last)
  {
    snprintf (buf, sizeof (buf), "%u %u", nntp_data->firstMessage,
					  nntp_data->lastMessage);
    dprint (2, (debugfile,
		"nntp_hcache_update: mutt_hcache_store index: %s\n", buf));
    mutt_hcache_store_raw (hc, "index", buf, strlen (buf) + 1, strlen);
  }
}
#endif

/* Remove bcache file */
static int nntp_bcache_delete (const char *id, body_cache_t *bcache, void *data)
{
  NNTP_DATA *nntp_data = data;
  anum_t anum;
  char c;

  if (!nntp_data || sscanf (id, ANUM "%c", &anum, &c) != 1 ||
      anum < nntp_data->firstMessage || anum > nntp_data->lastMessage)
  {
    if (nntp_data)
      dprint (2, (debugfile, "nntp_bcache_delete: mutt_bcache_del %s\n", id));
    mutt_bcache_del (bcache, id);
  }
  return 0;
}

/* Remove stale cached messages */
void nntp_bcache_update (NNTP_DATA *nntp_data)
{
  mutt_bcache_list (nntp_data->bcache, nntp_bcache_delete, nntp_data);
}

/* Remove hcache and bcache of newsgroup */
void nntp_delete_group_cache (NNTP_DATA *nntp_data)
{
  char file[_POSIX_PATH_MAX];

  if (!nntp_data || !nntp_data->nserv || !nntp_data->nserv->cacheable)
    return;

#ifdef USE_HCACHE
  nntp_hcache_namer (nntp_data->group, file, sizeof (file));
  cache_expand (file, sizeof (file), &nntp_data->nserv->conn->account, file);
  unlink (file);
  nntp_data->lastCached = 0;
  dprint (2, (debugfile, "nntp_delete_group_cache: %s\n", file));
#endif

  if (!nntp_data->bcache)
    nntp_data->bcache = mutt_bcache_open (&nntp_data->nserv->conn->account,
			nntp_data->group);
  if (nntp_data->bcache)
  {
    dprint (2, (debugfile, "nntp_delete_group_cache: %s/*\n", nntp_data->group));
    mutt_bcache_list (nntp_data->bcache, nntp_bcache_delete, NULL);
    mutt_bcache_close (&nntp_data->bcache);
  }
}

/* Remove hcache and bcache of all unexistent and unsubscribed newsgroups */
void nntp_clear_cache (NNTP_SERVER *nserv)
{
  char file[_POSIX_PATH_MAX];
  char *fp;
  struct dirent *entry;
  DIR *dp;

  if (!nserv || !nserv->cacheable)
    return;

  cache_expand (file, sizeof (file), &nserv->conn->account, NULL);
  dp = opendir (file);
  if (dp)
  {
    safe_strncat (file, sizeof (file), "/", 1);
    fp = file + strlen (file);
    while ((entry = readdir (dp)))
    {
      char *group = entry->d_name;
      struct stat sb;
      NNTP_DATA *nntp_data;
      NNTP_DATA nntp_tmp;

      if (mutt_strcmp (group, ".") == 0 ||
	  mutt_strcmp (group, "..") == 0)
	continue;
      *fp = '\0';
      safe_strncat (file, sizeof (file), group, strlen (group));
      if (stat (file, &sb))
	continue;

#ifdef USE_HCACHE
      if (S_ISREG (sb.st_mode))
      {
	char *ext = group + strlen (group) - 7;
	if (strlen (group) < 8 || mutt_strcmp (ext, ".hcache"))
	  continue;
	*ext = '\0';
      }
      else
#endif
      if (!S_ISDIR (sb.st_mode))
	continue;

      nntp_data = hash_find (nserv->groups_hash, group);
      if (!nntp_data)
      {
	nntp_data = &nntp_tmp;
	nntp_data->nserv = nserv;
	nntp_data->group = group;
	nntp_data->bcache = NULL;
      }
      else if (nntp_data->newsrc_ent || nntp_data->subscribed ||
	       option (OPTSAVEUNSUB))
	continue;

      nntp_delete_group_cache (nntp_data);
      if (S_ISDIR (sb.st_mode))
      {
	rmdir (file);
	dprint (2, (debugfile, "nntp_clear_cache: %s\n", file));
      }
    }
    closedir (dp);
  }
  return;
}

/* %a = account url
 * %p = port
 * %P = port if specified
 * %s = news server name
 * %S = url schema
 * %u = username */
const char *
nntp_format_str (char *dest, size_t destlen, size_t col, char op, const char *src,
		const char *fmt, const char *ifstring, const char *elsestring,
		unsigned long data, format_flag flags)
{
  NNTP_SERVER *nserv = (NNTP_SERVER *)data;
  ACCOUNT *acct = &nserv->conn->account;
  ciss_url_t url;
  char fn[SHORT_STRING], tmp[SHORT_STRING], *p;

  switch (op)
  {
    case 'a':
      mutt_account_tourl (acct, &url);
      url_ciss_tostring (&url, fn, sizeof (fn), U_PATH);
      p = strchr (fn, '/');
      if (p)
	*p = '\0';
      snprintf (tmp, sizeof (tmp), "%%%ss", fmt);
      snprintf (dest, destlen, tmp, fn);
      break;
    case 'p':
      snprintf (tmp, sizeof (tmp), "%%%su", fmt);
      snprintf (dest, destlen, tmp, acct->port);
      break;
    case 'P':
      *dest = '\0';
      if (acct->flags & M_ACCT_PORT)
      {
	snprintf (tmp, sizeof (tmp), "%%%su", fmt);
	snprintf (dest, destlen, tmp, acct->port);
      }
      break;
    case 's':
      strncpy (fn, acct->host, sizeof (fn) - 1);
      mutt_strlower (fn);
      snprintf (tmp, sizeof (tmp), "%%%ss", fmt);
      snprintf (dest, destlen, tmp, fn);
      break;
    case 'S':
      mutt_account_tourl (acct, &url);
      url_ciss_tostring (&url, fn, sizeof (fn), U_PATH);
      p = strchr (fn, ':');
      if (p)
	*p = '\0';
      snprintf (tmp, sizeof (tmp), "%%%ss", fmt);
      snprintf (dest, destlen, tmp, fn);
      break;
    case 'u':
      snprintf (tmp, sizeof (tmp), "%%%ss", fmt);
      snprintf (dest, destlen, tmp, acct->user);
      break;
  }
  return (src);
}

/* Automatically loads a newsrc into memory, if necessary.
 * Checks the size/mtime of a newsrc file, if it doesn't match, load
 * again.  Hmm, if a system has broken mtimes, this might mean the file
 * is reloaded every time, which we'd have to fix. */
NNTP_SERVER *nntp_select_server (char *server, int leave_lock)
{
  char file[_POSIX_PATH_MAX];
  char *p;
  int rc;
  struct stat sb;
  ACCOUNT acct;
  NNTP_SERVER *nserv;
  NNTP_DATA *nntp_data;
  CONNECTION *conn;
  ciss_url_t url;

  if (!server || !*server)
  {
    mutt_error _("No news server defined!");
    mutt_sleep (2);
    return NULL;
  }

  /* create account from news server url */
  acct.flags = 0;
  acct.port = NNTP_PORT;
  acct.type = M_ACCT_TYPE_NNTP;
  snprintf (file, sizeof (file), "%s%s",
	    strstr (server, "://") ? "" : "news://", server);
  if (url_parse_ciss (&url, file) < 0 ||
      (url.path && *url.path) ||
      !(url.scheme == U_NNTP || url.scheme == U_NNTPS) ||
      mutt_account_fromurl (&acct, &url) < 0)
  {
    mutt_error (_("%s is an invalid news server specification!"), server);
    mutt_sleep (2);
    return NULL;
  }
  if (url.scheme == U_NNTPS)
  {
    acct.flags |= M_ACCT_SSL;
    acct.port = NNTP_SSL_PORT;
  }

  /* find connection by account */
  conn = mutt_conn_find (NULL, &acct);
  if (!conn)
    return NULL;
  if (!(conn->account.flags & M_ACCT_USER) && acct.flags & M_ACCT_USER)
  {
    conn->account.flags |= M_ACCT_USER;
    conn->account.user[0] = '\0';
  }

  /* news server already exists */
  nserv = conn->data;
  if (nserv)
  {
    if (nserv->status == NNTP_BYE)
      nserv->status = NNTP_NONE;
    if (nntp_open_connection (nserv) < 0)
      return NULL;

    rc = nntp_newsrc_parse (nserv);
    if (rc < 0)
      return NULL;

    /* check for new newsgroups */
    if (!leave_lock && nntp_check_new_groups (nserv) < 0)
      rc = -1;

    /* .newsrc has been externally modified */
    if (rc > 0)
      nntp_clear_cache (nserv);
    if (rc < 0 || !leave_lock)
      nntp_newsrc_close (nserv);
    return rc < 0 ? NULL : nserv;
  }

  /* new news server */
  nserv = safe_calloc (1, sizeof (NNTP_SERVER));
  nserv->conn = conn;
  nserv->groups_hash = hash_create (1009, 0);
  nserv->groups_max = 16;
  nserv->groups_list = safe_malloc (nserv->groups_max * sizeof (nntp_data));

  rc = nntp_open_connection (nserv);

  /* try to create cache directory and enable caching */
  nserv->cacheable = 0;
  if (rc >= 0 && NewsCacheDir && *NewsCacheDir)
  {
    cache_expand (file, sizeof (file), &conn->account, NULL);
    p = *file == '/' ? file + 1 : file;
    while (1)
    {
      p = strchr (p, '/');
      if (p)
	*p = '\0';
      if ((stat (file, &sb) || (sb.st_mode & S_IFDIR) == 0) &&
	  mkdir (file, 0700))
      {
	mutt_error (_("Can't create %s: %s."), file, strerror (errno));
	mutt_sleep (2);
	break;
      }
      if (!p)
      {
	nserv->cacheable = 1;
	break;
      }
      *p++ = '/';
    }
  }

  /* load .newsrc */
  if (rc >= 0)
  {
    mutt_FormatString (file, sizeof (file), 0, NONULL (NewsRc),
		       nntp_format_str, (unsigned long)nserv, 0);
    mutt_expand_path (file, sizeof (file));
    nserv->newsrc_file = safe_strdup (file);
    rc = nntp_newsrc_parse (nserv);
  }
  if (rc >= 0)
  {
    /* try to load list of newsgroups from cache */
    if (nserv->cacheable && active_get_cache (nserv) == 0)
      rc = nntp_check_new_groups (nserv);

    /* load list of newsgroups from server */
    else
      rc = nntp_active_fetch (nserv);
  }

  if (rc >= 0)
    nntp_clear_cache (nserv);

#ifdef USE_HCACHE
  /* check cache files */
  if (rc >= 0 && nserv->cacheable)
  {
    struct dirent *entry;
    DIR *dp = opendir (file);

    if (dp)
    {
      while ((entry = readdir (dp)))
      {
	header_cache_t *hc;
	void *hdata;
	char *group = entry->d_name;

	p = group + strlen (group) - 7;
	if (strlen (group) < 8 || strcmp (p, ".hcache"))
	  continue;
	*p = '\0';
	nntp_data = hash_find (nserv->groups_hash, group);
	if (!nntp_data)
	  continue;

	hc = nntp_hcache_open (nntp_data);
	if (!hc)
	  continue;

	/* fetch previous values of first and last */
	hdata = mutt_hcache_fetch_raw (hc, "index", strlen);
	if (hdata)
	{
	  anum_t first, last;

	  if (sscanf (hdata, ANUM " " ANUM, &first, &last) == 2)
	  {
	    if (nntp_data->deleted)
	    {
	      nntp_data->firstMessage = first;
	      nntp_data->lastMessage = last;
	    }
	    if (last >= nntp_data->firstMessage &&
		last <= nntp_data->lastMessage)
	    {
	      nntp_data->lastCached = last;
	      dprint (2, (debugfile, "nntp_select_server: %s lastCached=%u\n",
			  nntp_data->group, last));
	    }
	  }
	}
	mutt_hcache_close (hc);
      }
      closedir (dp);
    }
  }
#endif

  if (rc < 0 || !leave_lock)
    nntp_newsrc_close (nserv);

  if (rc < 0)
  {
    hash_destroy (&nserv->groups_hash, nntp_data_free);
    FREE (&nserv->groups_list);
    FREE (&nserv->newsrc_file);
    FREE (&nserv->authenticators);
    FREE (&nserv);
    mutt_socket_close (conn);
    mutt_socket_free (conn);
    return NULL;
  }

  conn->data = nserv;
  return nserv;
}

/* Full status flags are not supported by nntp, but we can fake some of them:
 * Read = a read message number is in the .newsrc
 * New = not read and not cached
 * Old = not read but cached */
void nntp_article_status (CONTEXT *ctx, HEADER *hdr, char *group, anum_t anum)
{
  NNTP_DATA *nntp_data = ctx->data;
  unsigned int i;

  if (group)
    nntp_data = hash_find (nntp_data->nserv->groups_hash, group);

  if (!nntp_data)
    return;

  for (i = 0; i < nntp_data->newsrc_len; i++)
  {
    if ((anum >= nntp_data->newsrc_ent[i].first) &&
	(anum <= nntp_data->newsrc_ent[i].last))
    {
      /* can't use mutt_set_flag() because mx_update_context()
	 didn't called yet */
      hdr->read = 1;
      return;
    }
  }

  /* article was not cached yet, it's new */
  if (anum > nntp_data->lastCached)
    return;

  /* article isn't read but cached, it's old */
  if (option (OPTMARKOLD))
    hdr->old = 1;
}

/* calculate number of unread articles using .newsrc data */
void nntp_group_unread_stat (NNTP_DATA *nntp_data)
{
  unsigned int i;
  anum_t first, last;

  nntp_data->unread = 0;
  if (nntp_data->lastMessage == 0 ||
      nntp_data->firstMessage > nntp_data->lastMessage)
    return;

  nntp_data->unread = nntp_data->lastMessage - nntp_data->firstMessage + 1;
  for (i = 0; i < nntp_data->newsrc_len; i++)
  {
    first = nntp_data->newsrc_ent[i].first;
    if (first < nntp_data->firstMessage)
      first = nntp_data->firstMessage;
    last = nntp_data->newsrc_ent[i].last;
    if (last > nntp_data->lastMessage)
      last = nntp_data->lastMessage;
    if (first <= last)
      nntp_data->unread -= last - first + 1;
  }
}

/* Subscribe newsgroup */
NNTP_DATA *mutt_newsgroup_subscribe (NNTP_SERVER *nserv, char *group)
{
  NNTP_DATA *nntp_data;

  if (!nserv || !nserv->groups_hash || !group || !*group)
    return NULL;

  nntp_data = nntp_data_find (nserv, group);
  nntp_data->subscribed = 1;
  if (!nntp_data->newsrc_ent)
  {
    nntp_data->newsrc_ent = safe_calloc (1, sizeof (NEWSRC_ENTRY));
    nntp_data->newsrc_len = 1;
    nntp_data->newsrc_ent[0].first = 1;
    nntp_data->newsrc_ent[0].last = 0;
  }
  return nntp_data;
}

/* Unsubscribe newsgroup */
NNTP_DATA *mutt_newsgroup_unsubscribe (NNTP_SERVER *nserv, char *group)
{
  NNTP_DATA *nntp_data;

  if (!nserv || !nserv->groups_hash || !group || !*group)
    return NULL;

  nntp_data = hash_find (nserv->groups_hash, group);
  if (!nntp_data)
    return NULL;

  nntp_data->subscribed = 0;
  if (!option (OPTSAVEUNSUB))
  {
    nntp_data->newsrc_len = 0;
    FREE (&nntp_data->newsrc_ent);
  }
  return nntp_data;
}

/* Catchup newsgroup */
NNTP_DATA *mutt_newsgroup_catchup (NNTP_SERVER *nserv, char *group)
{
  NNTP_DATA *nntp_data;

  if (!nserv || !nserv->groups_hash || !group || !*group)
    return NULL;

  nntp_data = hash_find (nserv->groups_hash, group);
  if (!nntp_data)
    return NULL;

  if (nntp_data->newsrc_ent)
  {
    safe_realloc (&nntp_data->newsrc_ent, sizeof (NEWSRC_ENTRY));
    nntp_data->newsrc_len = 1;
    nntp_data->newsrc_ent[0].first = 1;
    nntp_data->newsrc_ent[0].last = nntp_data->lastMessage;
  }
  nntp_data->unread = 0;
  if (Context && Context->data == nntp_data)
  {
    unsigned int i;

    for (i = 0; i < Context->msgcount; i++)
      mutt_set_flag (Context, Context->hdrs[i], M_READ, 1);
  }
  return nntp_data;
}

/* Uncatchup newsgroup */
NNTP_DATA *mutt_newsgroup_uncatchup (NNTP_SERVER *nserv, char *group)
{
  NNTP_DATA *nntp_data;

  if (!nserv || !nserv->groups_hash || !group || !*group)
    return NULL;

  nntp_data = hash_find (nserv->groups_hash, group);
  if (!nntp_data)
    return NULL;

  if (nntp_data->newsrc_ent)
  {
    safe_realloc (&nntp_data->newsrc_ent, sizeof (NEWSRC_ENTRY));
    nntp_data->newsrc_len = 1;
    nntp_data->newsrc_ent[0].first = 1;
    nntp_data->newsrc_ent[0].last = nntp_data->firstMessage - 1;
  }
  if (Context && Context->data == nntp_data)
  {
    unsigned int i;

    nntp_data->unread = Context->msgcount;
    for (i = 0; i < Context->msgcount; i++)
      mutt_set_flag (Context, Context->hdrs[i], M_READ, 0);
  }
  else
    nntp_data->unread = nntp_data->lastMessage - nntp_data->newsrc_ent[0].last;
  return nntp_data;
}

/* Get first newsgroup with new messages */
void nntp_buffy (char *buf, size_t len)
{
  unsigned int i;

  for (i = 0; i < CurrentNewsSrv->groups_num; i++)
  {
    NNTP_DATA *nntp_data = CurrentNewsSrv->groups_list[i];

    if (!nntp_data || !nntp_data->subscribed || !nntp_data->unread)
      continue;

    if (Context && Context->magic == M_NNTP &&
	!mutt_strcmp (nntp_data->group, ((NNTP_DATA *)Context->data)->group))
    {
      unsigned int i, unread = 0;

      for (i = 0; i < Context->msgcount; i++)
	if (!Context->hdrs[i]->read && !Context->hdrs[i]->deleted)
	  unread++;
      if (!unread)
	continue;
    }
    strfcpy (buf, nntp_data->group, len);
    break;
  }
}