/*

 * help.c       -- Help command

 *

 * Copyright (C) 2006-2010 Mikael Berthe <mikael@lilotux.net>

 * Copyright (C) 2009      Myhailo Danylenko <isbear@ukrpost.net>

 *

 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307

 * USA

 */

/*

 * How it works

 *

 * Main calls help_init, that installs option guards. These guards do

 * nothing, but set help_dirs_stalled flag. When user issues help command,

 * it checks, if help_dirs_stalled flag is set, and if it is, it calls

 * init_help_dirs before performing help search.

 *

 * Options:

 *   lang       List of semicolon-separated language codes. If unset, will

 *              be detected from locale, with fallback to english.

 *   help_dirs  List of semicolon-seaparated directories, where search for

 *              help (in language subdirectories) will be performed.

 *              Defaults to DATA_DIR/mcabber/help.

 *   help_to_current  Print help to current buddy's buffer.

 *

 * XXX:

 *   Remove command list from hlp.txt and print detected list of all help

 *   topics?

 */

#include <glib.h>

#include <string.h>

#include <locale.h>

#include <sys/types.h>

#include <dirent.h>

#include "logprint.h"

#include "screen.h"

#include "hbuf.h"

#include "settings.h"

#include "utils.h"

static GSList   *help_dirs         = NULL;

static gboolean  help_dirs_stalled = TRUE;

void free_help_dirs(void)

{

  GSList *hel;

  for (hel = help_dirs; hel; hel = hel->next)

    g_free(hel->data);

  g_slist_free(help_dirs);

  help_dirs = NULL;

}

void dir_push_languages(const char *langs, const char *dir)

{

  const char *lstart = langs;

  const char *lend;

  char       *path   = expand_filename(dir);

  for (lend = strchr(lstart, ';'); lend; lend = strchr(lstart, ';')) {

    char *lang = g_strndup(lstart, lend - lstart);

    char *dir  = g_strdup_printf("%s/%s", path, lang);

    help_dirs = g_slist_append(help_dirs, dir);

    g_free(lang);

    lstart = lend + 1;

  }

  { // finishing element

    char *dir = g_strdup_printf("%s/%s", path, lstart);

    help_dirs = g_slist_append(help_dirs, dir);

  }

  g_free(path);

}

void init_help_dirs(void)

{

  const char *paths;

  const char *langs;

  char        lang[6];

  if (help_dirs)

    free_help_dirs();

  // initialize variables

  paths = settings_opt_get("help_dirs");

  if (!paths || !*paths)

#ifdef DATA_DIR

    paths = DATA_DIR "/mcabber/help";

#else

    paths = "/usr/local/share/mcabber/help;/usr/share/mcabber/help";

#endif

  langs = settings_opt_get("lang");

  if (!langs || !*langs) {

    char *locale = setlocale(LC_MESSAGES, NULL);

    // XXX crude method to distinguish between xx_XX xx xx@xxx

    // and C POSIX NULL etc.

    if (locale && isalpha(locale[0]) && isalpha(locale[1])

        && !isalpha(locale[2])) {

      lang[0] = locale[0];

      lang[1] = locale[1];

      if (lang[0] == 'e' && lang[1] == 'n')

        lang[2] = '\0';

      else {

        lang[2] = ';';

        lang[3] = 'e';

        lang[4] = 'n';

        lang[5] = '\0';

      }

      langs = lang;

    } else

      langs = "en";

  }

  { // parse

    const char *pstart = paths;

    const char *pend;

    for (pend = strchr(pstart, ';'); pend; pend = strchr(pstart, ';')) {

      char *path = g_strndup(pstart, pend - pstart);

      dir_push_languages(langs, path);

      g_free(path);

      pstart = pend + 1;

    }

    // last element

    dir_push_languages(langs, pstart);

  }

  help_dirs_stalled = FALSE;

}

static gboolean do_help_in_dir(const char *arg, const char *path, const char *jid)

{

  char       *fname;

  GIOChannel *channel;

  GString    *line;

  int         lines   = 0;

  if (arg && *arg)

    fname = g_strdup_printf("%s/hlp_%s.txt", path, arg);

  else

    fname = g_strdup_printf("%s/hlp.txt", path);

  channel = g_io_channel_new_file(fname, "r", NULL);

  if (!channel)

    return FALSE;

  line = g_string_new(NULL);

  while (TRUE) {

    gsize     endpos;

    GIOStatus ret;

    ret = g_io_channel_read_line_string(channel, line, &endpos, NULL);

    if (ret != G_IO_STATUS_NORMAL) // XXX G_IO_STATUS_AGAIN?

      break;

    line->str[endpos] = '\0';

    if (jid)

      scr_WriteIncomingMessage(jid, line->str, 0,

                               HBB_PREFIX_INFO|HBB_PREFIX_NOFLAG, 0);

    else

      scr_LogPrint(LPRINT_NORMAL, "%s", line->str);

    ++lines;

  }

  g_io_channel_unref(channel);

  g_string_free(line, TRUE);

  if (!lines)

    return FALSE;

  if (!jid) {

    scr_setmsgflag_if_needed(SPECIAL_BUFFER_STATUS_ID, TRUE);

    scr_setattentionflag_if_needed(SPECIAL_BUFFER_STATUS_ID, TRUE,

                                   ROSTER_UI_PRIO_STATUS_WIN_MESSAGE, prio_max);

  }

  return TRUE;

}

void help_process(char *arg)

{

  gchar      *string;

  const char *jid    = NULL;

  gboolean    done   = FALSE;

  if (help_dirs_stalled)

    init_help_dirs();

  { // check input

    char *c;

    for (c = arg; *c; ++c)

      if (!isalnum(*c) && *c != '-' && *c != '_') {

        scr_LogPrint(LPRINT_NORMAL, "Wrong help expression, "

                     "it can contain only alphbetic, numeric"

                     " characters and symbols '-' and '_'.");

        return;

      }

    string = g_strdup(arg);

    mc_strtolower(string);

  }

  if (settings_opt_get_int("help_to_current") && CURRENT_JID)

    jid = CURRENT_JID;

  { // search

    GSList *hel;

    for (hel = help_dirs; hel && !done; hel = hel->next) {

      char *dir = (char *)hel->data;

      done = do_help_in_dir(string, dir, jid);

    }

  }

  if (!done && string && *string) { // match and print any similar topics

    GSList *hel;

    GSList *matches = NULL;

    for (hel = help_dirs; hel; hel = hel->next) {

      const char *path = (const char *)hel->data;

      DIR        *dd   = opendir(path);

      if (dd) {

        struct dirent *file;

        for (file = readdir(dd); file; file = readdir(dd)) {

          const char *name = file->d_name;

          if (name && name[0] == 'h' && name[1] == 'l' &&

                      name[2] == 'p' && name[3] == '_') {

            const char *nstart = name + 4;

            const char *nend   = strrchr(nstart, '.');

            if (nend) {

              gsize len = nend - nstart;

              if (g_strstr_len(nstart, len, string)) {

                gchar *match = g_strndup(nstart, len);

                if (!g_slist_find_custom(matches, match,

                                         (GCompareFunc)strcmp))

                  matches = g_slist_append(matches, match);

                else

                  g_free(match);

                done = TRUE;

              }

            }

          }

        }

        closedir(dd);

      }

    }

    if (done) {

      GString *message = g_string_new("No exact match found. "

                                      "Keywords, that contain this word:");

      GSList  *wel;

      for (wel = matches; wel; wel = wel->next) {

        gchar *word = (gchar *)wel->data;

        g_string_append_printf(message, " %s,", word);

        g_free(wel->data);

      }

      message->str[message->len - 1] = '.';

      g_slist_free(matches);

      {

        char *msg = g_string_free(message, FALSE);

        if (jid)

          scr_WriteIncomingMessage(jid, msg, 0,

                                   HBB_PREFIX_INFO|HBB_PREFIX_NOFLAG, 0);

        else

          scr_LogPrint(LPRINT_NORMAL, "%s", msg);

        g_free(msg);

      }

    }

  }

  if (!done) {

    if (jid) // XXX

      scr_WriteIncomingMessage(jid, "No help found.", 0,

                               HBB_PREFIX_INFO|HBB_PREFIX_NOFLAG, 0);

    else

      scr_LogPrint(LPRINT_NORMAL, "No help found.");

  }

  g_free(string);

}

static gchar *help_guard(const gchar *key, const gchar *new_value)

{

  help_dirs_stalled = TRUE;

  return g_strdup(new_value);

}

void help_init(void)

{

  settings_set_guard("lang", help_guard);

  settings_set_guard("help_dirs", help_guard);

}

/* vim: set expandtab cindent cinoptions=>2\:2(0 sw=2 ts=2:  For Vim users... */