<?php

//
// xmlrpc1.inc : data and management plane xmlrpc methods for logging metering data
//               API version 1
//
// Copyright (c) 2008-2009 jokamajo.org
//
// 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.
//
// $Id$
//

/**
 * Implementation of hook_xmlrpc().
 * Mapping external XML-RPC methods to callback functions.
 * API versioning; logger.flukso.net/xmlrpc/1 maps to xmlrpc1.inc
 */
function logger_xmlrpc() {
  return array(
    array(
      'logger.auth', // External method name.
      '_logger_auth', // Drupal callback function to run + api version 1
      array('string', 'array'), // Return value's type, then any parameter types (accept, auth)
      'Authenticate a device' // Description.
    ),
    array(
      'logger.heartbeat', // External method name.
      '_logger_heartbeat', // Drupal callback function to run  + api version 1
      array('array', 'array', 'array'), // Return value's type, then any parameter types (return, auth, monitor)
      'Send a heartbeat to the logger.' // Description.
    ),
    array(
      'logger.measurementAdd', // External method name.
      '_logger_measurement_add', // Drupal callback function to run + api version 1
      array('string', 'array', 'array'), // Return value's type, then any parameter types (action, auth, logs)
      'Submit measurements to the logger.' // Description.
    ),
  );
}

/**
 * Callback functions registered in the logger_xmlrpc section
 */
function _logger_auth($auth) {
  if (_logger_authenticate_hmac_sha1($auth))
    return 'authenticated!';
  else
    return xmlrpc_error(-31000, t('Authentication failed.'));
}

function _logger_heartbeat($auth, $monitor) {
  if (_logger_authenticate_hmac_sha1($auth, $monitor)) {
    $device = db_fetch_object(db_query("SELECT sha, upgrade, resets FROM {logger_devices} WHERE device = '%s'", $auth['device']));
    $device->resets += $monitor['reset'];
    db_query("UPDATE {logger_devices} SET access = %d, version = %d, upgrade = %d, resets = %d, uptime = %d, memtotal = %d, memfree = %d, memcached = %d, membuffers = %d, uart_oe = %d WHERE device = '%s'", time(), $monitor['version'], 0, $device->resets, $monitor['uptime'], $monitor['memtotal'], $monitor['memfree'], $monitor['memcached'], $monitor['membuffers'], $monitor['uart_oe'], $auth['device']);

    $action['upgrade'] = (int)$device->upgrade;
    if ($action['upgrade']) {
      $action['timestamp'] = time();
      $action['signature'] = hash_hmac('sha1', $action['timestamp'] .':'. $action['upgrade'] .':'. $device->sha, $device->sha);
    }
    return $action;
  }
  else
    return xmlrpc_error(-31000, t('Authentication failed.'));
}

function _logger_measurement_add($auth, $logs) {
  if (_logger_authenticate_hmac_sha1($auth, $logs)) {
    $info = 'added 5min interval measurements to the log';
    $path = new stdClass();
    $path->root = XMLRPC_PATH . '/' . XMLRPC_MODULE; // need to hardcode drupal_get_path('module', 'logger');
    $path->base = $path->root .'/data/base/';
    $path->night = $path->root .'/data/night/';
    foreach ($logs as $meter => $measurements) {
      //load the normalisation factor, relative to 1pulse = 1Wh
      $meterdata = db_fetch_object(db_query("SELECT device, night, factor FROM {logger_meters} WHERE meter = '%s'", $meter));
      if ($meterdata->device == $auth['device']) { // extra security check
        $command = $path->root .'/rrdtool update '. $path->base . $meter .'.rrd ';
        ksort($measurements); // sort the key-value pairs in the associative array by key, i.e. the timestamp
        foreach ($measurements as $timestamp => $value) {
          if (is_numeric($timestamp) and is_numeric($value)) {
            $command .= $timestamp .':'. $value*$meterdata->factor .' ';
          }
          else {
            watchdog_xmlrpc('logger.measurementAdd', 'corrupted input data for %meter : %timestamp : %value', array('%meter' => $meter, '%timestamp' => $timestamp, '%value' => $value),WATCHDOG_ERROR);
          }
        }

        system($command, $return);

        if ($return == 0) {
          // update the night rrd every day at 6AM local time
          if (time() > $meterdata->night) {
            $midnight = _logger_midnight(time(), $auth['device']);
            $start = $midnight + 7200; // 2AM local time
            $end = $start + 10800; // 3h time interval
            $command = $path->root ."/rrdtool fetch ". $path->base . $meter .".rrd AVERAGE -r 900 -s ". $start ." -e ". $end ." | tail -n 12 | awk -F': ' '{SUM += $2} END {print SUM/12}'";
            $night = (float)shell_exec($command); //test shell_exec iso system
            $command = $path->root .'/rrdtool update '. $path->night . $meter .'.rrd '. $end .':'. $night;
            system($command, $return);
            if ($return == 0) {
                watchdog_xmlrpc('logger.measurementAdd', 'successful update for night rrd: %command | midnight = %midnight', array('%command' => $command, '%midnight' => $midnight), WATCHDOG_NOTICE); //debugging
            }
            else {
              watchdog_xmlrpc('logger.measurementAdd', 'error updating night rrd: %command', array('%command' => $command), WATCHDOG_ERROR); //debugging
            }
            $meterdata->night = $midnight + 108000; //add an offset of 30h = 6AM local time
          }
          // {logger_meters} is updated with the true metervalue $value, NOT $value*$meterdata->factor since we're not normalising this entry!
          db_query("UPDATE {logger_meters} SET access = %d, night = %d, value = %d WHERE meter = '%s'", time(), $meterdata->night, $value, $meter);
        }
        else {
          watchdog_xmlrpc('logger.measurementAdd', 'shell command execution failed: %return %command', array('%command' => $command, '%return' => $return), WATCHDOG_ERROR);
        }
      }
    }
    return $command; //using $command for testing purposes, replace by $info afterwards
  }
  else
    return xmlrpc_error(-31000, t('Authentication failed.'));
}

/**
 * Calculate the most recent midnight for this device based on the user's timezone
 */
function _logger_midnight($timestamp, $device) {
  $timezone = db_result(db_query("SELECT u.timezone FROM {logger_devices} ld INNER JOIN {users} u ON ld.uid = u.uid WHERE ld.device = '%s'", $device));
  // add one day to make sure $midnight > $timestamp
  $midnight = floor($timestamp/86400 + 1)*86400 - $timezone;
  // search for first $midnight < $timestamp
  while ($midnight > $timestamp) $midnight -= 86400;
  return $midnight;
}

function _logger_authenticate_hmac_sha1($auth, $message) {
  $auth['key'] = db_result(db_query("SELECT sha FROM {logger_devices} WHERE device = '%s'", $auth['device']));
  if (hash_hmac('sha1', $auth['timestamp'] .':'. _logger_serialise($message) .':'. $auth['key'], $auth['key']) == $auth['signature'] && $auth['timestamp'] > time() - 300) {
     // debugging:  watchdog_xmlrpc('logger.auth', 'HMAC-SHA1 authentication succeeded for device: %device', array('%device' => $auth['device']), WATCHDOG_NOTICE);
    return TRUE;
  }
  else {
    watchdog_xmlrpc('logger.auth', 'HMAC-SHA1 authentication failed for device: %device', array('%device' => $auth['device']), WATCHDOG_ERROR);
    return FALSE;
  }
}

function _logger_serialise($data) {
  if (is_array($data)) {
    $sequence = '';
    foreach ($data as $key => $value) {
      $sequence .= (string)$key . _logger_serialise($value);
    }
    return $sequence;
  }
  else {
    return (string)$data;
  }
}