/* tinyproxy - A fast light-weight HTTP proxy
 * Copyright (C) 2000 Robert James Kaes <rjkaes@users.sourceforge.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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

/* This module handles the statistics for tinyproxy. There are only two
 * public API functions. The reason for the functions, rather than just a
 * external structure is that tinyproxy is now multi-threaded and we can
 * not allow more than one child to access the statistics at the same
 * time. This is prevented by a mutex. If there is a need for more
 * statistics in the future, just add to the structure, enum (in the header),
 * and the switch statement in update_stats().
 */

#include "tinyproxy.h"

#include "log.h"
#include "heap.h"
#include "html-error.h"
#include "stats.h"
#include "utils.h"

struct stat_s
{
  unsigned long int num_reqs;
  unsigned long int num_badcons;
  unsigned long int num_open;
  unsigned long int num_refused;
  unsigned long int num_denied;
};

static struct stat_s *stats;

/*
 * Initialize the statistics information to zero.
 */
void
init_stats (void)
{
  stats = malloc_shared_memory (sizeof (struct stat_s));
  if (stats == MAP_FAILED)
    return;

  memset (stats, 0, sizeof (struct stat_s));
}

/*
 * Display the statics of the tinyproxy server.
 */
int
showstats (struct conn_s *connptr)
{
  static char *msg =
    "<?xml version=\"1.0\" encoding=\"UTF-8\" ?>\n"
    "<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.1//EN\" "
    "\"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd\">\n"
    "<html>\n"
    "<head><title>%s version %s run-time statistics</title></head>\n"
    "<body>\n"
    "<h1>%s version %s run-time statistics</h1>\n"
    "<p>\n"
    "Number of open connections: %lu<br />\n"
    "Number of requests: %lu<br />\n"
    "Number of bad connections: %lu<br />\n"
    "Number of denied connections: %lu<br />\n"
    "Number of refused connections due to high load: %lu\n"
    "</p>\n"
    "<hr />\n"
    "<p><em>Generated by %s version %s.</em></p>\n" "</body>\n" "</html>\n";

  char *message_buffer;
  char opens[16], reqs[16], badconns[16], denied[16], refused[16];
  FILE *statfile;

  snprintf (opens, sizeof (opens), "%lu", stats->num_open);
  snprintf (reqs, sizeof (reqs), "%lu", stats->num_reqs);
  snprintf (badconns, sizeof (badconns), "%lu", stats->num_badcons);
  snprintf (denied, sizeof (denied), "%lu", stats->num_denied);
  snprintf (refused, sizeof (refused), "%lu", stats->num_refused);

  if (!config.statpage || (!(statfile = fopen (config.statpage, "r"))))
    {
      message_buffer = safemalloc (MAXBUFFSIZE);
      if (!message_buffer)
        return -1;

      snprintf (message_buffer, MAXBUFFSIZE, msg,
                PACKAGE, VERSION, PACKAGE, VERSION,
                stats->num_open,
                stats->num_reqs,
                stats->num_badcons, stats->num_denied,
                stats->num_refused, PACKAGE, VERSION);

      if (send_http_message (connptr, 200, "OK", message_buffer) < 0)
        {
          safefree (message_buffer);
          return -1;
        }

      safefree (message_buffer);
      return 0;
    }

  add_error_variable (connptr, "opens", opens);
  add_error_variable (connptr, "reqs", reqs);
  add_error_variable (connptr, "badconns", badconns);
  add_error_variable (connptr, "deniedconns", denied);
  add_error_variable (connptr, "refusedconns", refused);
  add_standard_vars (connptr);
  send_http_headers (connptr, 200, "Statistic requested");
  send_html_file (statfile, connptr);
  fclose (statfile);

  return 0;
}

/*
 * Update the value of the statistics. The update_level is defined in
 * stats.h
 */
int
update_stats (status_t update_level)
{
  switch (update_level)
    {
    case STAT_BADCONN:
      ++stats->num_badcons;
      break;
    case STAT_OPEN:
      ++stats->num_open;
      ++stats->num_reqs;
      break;
    case STAT_CLOSE:
      --stats->num_open;
      break;
    case STAT_REFUSE:
      ++stats->num_refused;
      break;
    case STAT_DENIED:
      ++stats->num_denied;
      break;
    default:
      return -1;
    }

  return 0;
}