<?php

//
// logger.module : support module for charting data stored in RRD's
// 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.
//
// $Id$
//

/**
 * @file
 * Support module for charting data stored in RRD's
 */


/**
 * Constants
 */
define('RED',    'F1572F');
define('BLUE',   '44C3D3');
define('GREEN',  '7AAB5A');
define('ORANGE', 'F37E2B');
define('YELLOW', 'FBEB0D');
define('PURPLE', 'A052A0');

/**
 * Implementation of hook_perm().
 */
function logger_perm() {
  return array('logger');
}

/**
 * Implementation of hook_menu() for logger
 * Don't forget to create a primary menu item in the Drupal administration section with the title 'ecology' linking to the '/logger' path
 */
function logger_menu() {
  $items = array();

  $items['admin/settings/logger'] = array(
    'title'               => 'Logger settings',
    'description'         => 'Configure settings for logging metering values.',
    'page callback'       => 'drupal_get_form',
    'page arguments'      => array('_logger_admin_settings'),
    'access arguments'    => array('administer site configuration'),
  );
  $items['logger'] = array(
    'title'               => 'your dashboard', // isn't printed as title on the page, therefore resort to drupal_set_title (t('your ecological dashboard')) in ecology_dashboard;
    'description'         => 'Configure settings for logging metering values.',
    'page callback'       => '_logger_dashboard', //takes the callback from the MENU_DEFAULT_LOCAL_TASK -> lightest level-two menu
    'page arguments'      => array('electricity', 'main', 'hour'),
    'access callback'     => TRUE,
    'type'                => MENU_CALLBACK,
  );
  $items['logger/add'] = array(
    'title'               => 'add this user to the chart',
    'page callback'       => '_logger_add',
    'access arguments'    => array('logger'),
    'type'                => MENU_CALLBACK,
  );
  $items['logger/remove'] = array(
    'title'               => 'remove this user from the chart',
    'page callback'       => '_logger_remove',
    'access arguments'    => array('logger'),
    'type'                => MENU_CALLBACK,
  );
  $items['logger/unit'] = array(
    'title'               => 'change the unit',
    'page callback'       => '_logger_unit',
    'access arguments'    => array('logger'),
    'type'                => MENU_CALLBACK,
  );
  $items['logger/electricity'] = array(
    'title'               => 'electricity',
//    'page callback'       => '_logger_dashboard',
//    'page arguments'      => array('electricity', 'main', 'hour'),
    'access callback'     => TRUE,
    'type'                => MENU_DEFAULT_LOCAL_TASK,
  );

/**
  $items['logger/water'] = array(
    'title'               => 'water',
    'page callback'       => '_logger_dashboard',
    'page arguments'      => array('water', 'main', 'hour'),
    'access callback'     => TRUE,
    'type'                => MENU_LOCAL_TASK,
  );
  $items['logger/gas'] = array(
    'title'               => 'gas',
    'page callback'       => '_logger_dashboard',
    'page arguments'      => array('gas', 'main', 'hour'),
    'access callback'     => TRUE,
    'type'                => MENU_LOCAL_TASK,
  );
**/

  $items['logger/electricity/hour'] = array(
    'title'               => 'hour',
    'page callback'       => '_logger_dashboard',
    'page arguments'      => array('electricity', 'main', 'hour'),
    'access callback'     => TRUE,
    'type'                => MENU_LOCAL_TASK,
    'weight'              => 0,
  );
  $items['logger/electricity/day'] = array(
    'title'               => 'day',
    'page callback'       => '_logger_dashboard',
    'page arguments'      => array('electricity', 'main', 'day'),
    'access callback'     => TRUE,
    'type'                => MENU_LOCAL_TASK,
    'weight'              => 1,
  );
  $items['logger/electricity/month'] = array(
    'title'               => 'month',
    'page callback'       => '_logger_dashboard',
    'page arguments'      => array('electricity', 'main', 'month'),
    'access callback'     => TRUE,
    'type'                => MENU_LOCAL_TASK,
    'weight'              => 2,
  );
  $items['logger/electricity/year'] = array(
    'title'               => 'year',
    'page callback'       => '_logger_dashboard',
    'page arguments'      => array('electricity', 'main', 'year'),
    'access callback'     => TRUE,
    'type'                => MENU_LOCAL_TASK,
    'weight'              => 3,
  );
  $items['logger/electricity/night'] = array(
    'title'               => 'night',
    'page callback'       => '_logger_dashboard',
    'page arguments'      => array('electricity', 'main', 'night'),
    'access callback'     => TRUE,
    'type'                => MENU_LOCAL_TASK,
    'weight'              => 4,
  );
  $items['installation'] = array(
    'title'               => '',
    'description'         => 'Howto install a Fluksometer',
    'page callback'       => '_logger_installation',
    'access callback'     => TRUE,
    'type'                => MENU_CALLBACK,
  );

  return $items;
}


function _logger_installation(){
  $output = '<div class="install">';
  $output .= "<a class='img' href = 'http://www.flukso.net/installation'><img src='http://www.flukso.net/sites/default/files/images/step1.png' height='120' width='150' alt='step 1'/></a>";
  $output .= "<p><b>STEP 1: CONFIGURING WIFI</b><br/>Power up the Fluksometer. Connect your computer to the Fluksometer's ethernet port. Surf to <a href = 'http://192.168.255.1'>http://192.168.255.1</a>. Configure the wireless interface with the proper name and security key.</p>";
  $output .= "<a class='img' href = 'http://www.flukso.net/installation'><img src='http://www.flukso.net/sites/default/files/images/step2.png' height='120' width='150' alt='step 2'/></a>";
  $output .= "<p><b>STEP 2: SECURING THE FLUKSOMETER</b><br/>Disconnect all cables from the Fluksometer. Find a suitable location near the fuse box to install the Fluksometer. Secure the Fluksometer with the plastic cable tie.</p>";
  $output .= "<a class='img' href = 'http://www.flukso.net/installation'><img src='http://www.flukso.net/sites/default/files/images/step3.png' height='120' width='150' alt='step 3'/></a>";
  $output .= "<p><b>STEP 3: ATTACHING THE CURRENT CLAMP</b><br/>For safety reasons, switch off the main electricity supply. For a single phase supply, attach the current clamp to one of the two cables running from the electricity meter to the fuse box. Close the clamp firmly.</p>";
  $output .= "<a class='img' href = 'http://www.flukso.net/installation'><img src='http://www.flukso.net/sites/default/files/images/step4.png' height='120' width='150' alt='step 4'/></a>";
  $output .= "<p><b>STEP 4: CONNECTING THE CLAMP'S SENSOR CABLE</b><br/>Connect the cable from the current clamp to the Fluksometer's input port. Take care of connecting the black and red cable as shown in the drawing on the right. Only apply gentle force when fastening the two screws.</p>";
  $output .= "<a class='img' href = 'http://www.flukso.net/installation'><img src='http://www.flukso.net/sites/default/files/images/step5.png' height='120' width='150' alt='step 4'/></a>";
  $output .= "<p><b>STEP 5: POWERING UP</b><br/>Switch the main electricity supply back on. Activate the Fluksometer by connecting the power plug.</p>";
  $output .= "</div>";

  return $output;
}

/**
 * Callback functions registered in the logger_menu section
 */
function _logger_dashboard($type, $function, $interval) {
  // watchdog('dashboard', 'arguments: %type, %function, %interval', array('%type' => $type, '%function' => $function, '%interval' => $interval), WATCHDOG_DEBUG);

  if (user_access('logger')) {
    drupal_set_title(t('your dashboard'));
    global $user;
  }
  else {  //show users who don't have 'logger' permissions icrarus'es chart
    drupal_set_title(t("a Fluksonian's dashboard"));
    $user = new stdClass();
    $user->uid = 1;
    $user->name = 'icarus75';
    $user->timezone = '3600';
  }

  $root_path = drupal_get_path('module', 'logger');
  $graph_path = $root_path .'/graphs/'. $interval .'/';
  $pngid = md5(uniqid()); //generate random numbers for the png chart so that the browser doesn't use the cached one, use cron to clean up the dir hourly
  switch ($interval) {
    case 'hour':
      $data_path = $root_path .'/data/base/';
      $start = 'end-1h';
      break;
    case 'day':
      $data_path = $root_path .'/data/base/';
      $start = 'end-1d';
      break;
    case 'month':
      $data_path = $root_path .'/data/base/';
      $start = 'end-60d';
      break;
    case 'year':
      $data_path = $root_path .'/data/base/';
      $start = 'end-1y';
      break;
    case 'night':
      $data_path = $root_path .'/data/night/';
      $start = 'end-60d';
      break;
  }

  $meter = db_fetch_object(db_query("SELECT meter, unit FROM {logger_meters} WHERE uid = %d AND type = '%s' AND function = '%s'", $user->uid, $type, $function));
  switch ($type) {
    case 'electricity':
      switch ($meter->unit) {
        case 'watt':
          $meter->factor = 3600; // 1Wh/s = 3600 W
          break;
        case 'kwh':
          $meter->unit = 'kWh/year';
          $meter->factor = 31536;
          break;
        case 'eur':
          $meter->unit = 'euro/year';
          $meter->factor = 5676; // 18 EURcent/kWh
          break;
        case 'aud':
          $meter->unit = 'aud/year';
          $meter->factor = 5991; // 19 AUDcent/kWh
          break;
      }
  }

  $color = array(RED, BLUE, GREEN, YELLOW, PURPLE);
  $string->def  = ' DEF:data0='. $data_path . $meter->meter .'.rrd:meter:AVERAGE CDEF:meter0=data0,'. $meter->factor .',* VDEF:min0=meter0,MINIMUM VDEF:max0=meter0,MAXIMUM VDEF:avg0=meter0,AVERAGE VDEF:last0=meter0,LAST';
  $string->line = ' COMMENT:"\s" LINE1:meter0#'. $color[0] .':'.'"'. substr($user->name.'               ', 0, 15) .'"'.' GPRINT:min0:"min\:%5.0lf" GPRINT:max0:"\tmax\:%5.0lf" GPRINT:avg0:"\tavg\:%5.0lf" GPRINT:last0:"\tlast\:%5.0lf\l"';

  if (user_access('logger') || user_access('staff')) { //allow Veerle to watch the graphs
    $result = db_query("SELECT u.name, lm.meter FROM (({users} u INNER JOIN {user_relationships} ur ON u.uid = ur.requestee_id) INNER JOIN {user_relationship_types} urt ON ur.rtid = urt.rtid) INNER JOIN {logger_meters} lm ON u.uid = lm.uid WHERE ur.requester_id = %d AND urt.name = '%s' AND type = '%s' AND function = '%s' ORDER BY ur.rid", $user->uid, 'subscription', $type, $function);
    $i = 0;
    while ($subscription = db_fetch_object($result)) {
      $i += 1;
      // print_r($subscription);
      $string->def  .= ' DEF:data'. $i .'='. $data_path . $subscription->meter .'.rrd:meter:AVERAGE CDEF:meter'. $i .'=data'. $i .','. $meter->factor .',* VDEF:min'. $i .'=meter'. $i .',MINIMUM VDEF:max'. $i .'=meter'. $i .',MAXIMUM VDEF:avg'. $i .'=meter'. $i .',AVERAGE VDEF:last'. $i .'=meter'. $i .',LAST';
      $string->line .= ' LINE1:meter'. $i .'#'. $color[$i] .':'.'"'. substr($subscription->name.'               ', 0, 15) .'"'.' GPRINT:min'. $i .':"min\:%5.0lf" GPRINT:max'. $i .':"\tmax\:%5.0lf" GPRINT:avg'. $i .':"\tavg\:%5.0lf" GPRINT:last'. $i .':"\tlast\:%5.0lf\l"';
    }
  }

  //construct the TZ=GMT-02:00 format from the $user->timezone object updated by the autotimezone module
  if ($user->timezone >= 0)
    $TZ = 'TZ="GMT-';
  else
    $TZ = 'TZ="GMT+';
  $TZ .= gmdate('h:i', abs($user->timezone)) .'" ';
  //insert the TZ prior to launching rrdtool to obtain a proper time conversion
  $command = $TZ . $root_path .'/rrdtool graph '. $graph_path . $pngid .'.png -s '. $start .' --vertical-label '. $meter->unit .' --lower-limit 0 -w 500 -h 350 -E -X 0 --font LEGEND:8:';
  $command .= $string->def;
  $command .= $string->line;
  exec($command, $output, $return_var);
  // watchdog('dashboard', 'arguments: %command ++ %output ++ %return_var', array('%command' => $command, '%output' => serialize($output), '%return_var' => $return_var), WATCHDOG_DEBUG);
  return theme('chart', $graph_path . $pngid .'.png');
}

function _logger_add($uid) {
  global $user;
  $rtid = db_result(db_query("SELECT rtid FROM {user_relationship_types} WHERE name = '%s'", 'subscription'));
  $result = db_fetch_array(db_query("SELECT COUNT(rid), MAX(rid) FROM {user_relationships} WHERE requester_id = %d AND rtid = %d GROUP BY rtid", $user->uid, $rtid));

  // max subscriptions = 4
  if ($result['COUNT(rid)'] < 4) {
    user_relationships_request_relationship($user->uid, $uid, $rtid, TRUE);
  }
  else {
    //check whether the requested relationship doesn't already exist
    if (!db_result(db_query("SELECT rid FROM {user_relationships} WHERE requester_id = %d AND requestee_id = %d AND rtid = %d", $user->uid, $uid, $rtid))) {
      // if not, delete the most recently added relationship and replace it with the newly selected one
      db_query("DELETE FROM {user_relationships} WHERE rid = %d", $result['MAX(rid)']);
      user_relationships_request_relationship($user->uid, $uid, $rtid, TRUE);
    }
  }

  _logger_cache_clear('subscriptions');
  $destination = drupal_get_destination();
  drupal_goto($destination);
}

function _logger_remove($rid) {
  global $user;
  // check whether the to-be-deleted relationship was created by the same user
  if ($user->uid == db_result(db_query("SELECT requester_id FROM {user_relationships} WHERE rid = %d", $rid))) {
    db_query("DELETE FROM {user_relationships} WHERE rid = %d", $rid);
  }
  else {
    watchdog('relationships', 'attempt to delete rid %rid by non-authorized user %uid', array('%rid' => $rid, '%uid' => $user->uid), WATCHDOG_ERROR);
  }

  _logger_cache_clear('subscriptions');
  $destination = drupal_get_destination();
  drupal_goto($destination);
}

function _logger_unit($unit) {
  global $user;
  // hardcoded type and function
  db_query("UPDATE {logger_meters} SET unit = '%s' WHERE uid = %d AND type = '%s' AND function = '%s'", $unit, $user->uid, 'electricity', 'main');

  _logger_cache_clear('unit');
  $destination = drupal_get_destination();
  drupal_goto($destination);
}

/**
 * Clear the specific (per user) cache entry in the {cache_block} table
 */
function _logger_cache_clear($delta) {
  global $theme;
  //the theme variable isn't set on these callbacks so force it
  $theme = 'flukso';

  $block = db_fetch_object(db_query("SELECT * FROM {blocks} WHERE module = '%s' AND delta = '%s' AND theme = '%s'", 'logger', $delta, 'flukso'));
  $cid = _block_get_cache_id($block);
  // prevent the whole chache_block being cleared when _block_get_cache_id returns an empty string (e.g. uid = 1)
  if ($cid != '') cache_clear_all($cid, 'cache_block');
  //watchdog('block_cache', '%cid | %cache', array('%cid' => $cid, '%cache' => variable_get('block_cache', 100)), WATCHDOG_DEBUG);
}

/**
 * Implementation of hook_user() for logger
 * Flush the fluksonians block entries in the block cache 
 */
function logger_user($op) {
  switch($op) {
    // new user is being inserted into the database
    case 'insert':
      // flush the fluksonians block entries
      cache_clear_all('logger:fluksonians', 'cache_block', TRUE);
      break;
  }
}

/**
 * Implementation of hook_theme() for logger
 */
function logger_theme() {
  return array(
    'chart' => array(
      'arguments' => array('chart' => NULL),
    ),
    'logger_item_list' => array(
      'arguments' => array('items' => NULL, 'title' => NULL),
    ),
  );
}

/**
 * Theming the chart
 */
function theme_chart($chart) {
  $output .= '<p id="chart"><img src="'. base_path() . $chart .'" alt="Flukso"/></p><!-- end chart-->';
  return $output;
}

/**
 * Implementation of hook_block() for logger
 * Adds two blocks to the logger pages for (de-)selecting users and
 * another one for selecting the desired unit
 */
function logger_block($op = 'list', $delta = 0, $edit = array()) {
  global $user;

  switch ($op) {
    case 'list':
      $blocks['subscriptions']['info'] = t('Subscriptions');
      $blocks['subscriptions']['status'] = TRUE;
      $blocks['subscriptions']['region'] = 'right';
      $blocks['subscriptions']['weight'] = 0;
      $blocks['subscriptions']['pages'] = 'logger<br />logger/*';
      $blocks['subscriptions']['cache'] = BLOCK_CACHE_PER_USER;

      $blocks['fluksonians']['info'] = t('Fluksonians');
      $blocks['fluksonians']['status'] = TRUE;
      $blocks['fluksonians']['region'] = 'right';
      $blocks['fluksonians']['weight'] = 1;
      $blocks['fluksonians']['pages'] = 'logger<br />logger/*';
      $blocks['fluksonians']['cache'] = BLOCK_CACHE_PER_USER;

      $blocks['unit']['info'] = t('Unit');
      $blocks['unit']['status'] = TRUE;
      $blocks['unit']['region'] = 'right';
      $blocks['unit']['weight'] = 2;
      $blocks['unit']['pages'] = 'logger<br />logger/*';
      $blocks['unit']['cache'] = BLOCK_CACHE_PER_USER;

      $blocks['publish']['info'] = t('Publish');
      $blocks['publish']['status'] = TRUE;
      $blocks['publish']['region'] = 'content';
      $blocks['publish']['weight'] = 3;
      $blocks['publish']['pages'] = 'logger<br />logger/*';
      $blocks['publish']['cache'] = BLOCK_CACHE_PER_ROLE;

      return $blocks;

    case 'view':
      //pass along our current destination in the query string so that logger_add and logger_remove can return after processing their task
      $destination = drupal_get_destination();

      if ($delta == 'subscriptions' && user_access('logger')) {
        $result = db_query("SELECT u.uid, u.name, ur.rid FROM ({users} u INNER JOIN {user_relationships} ur ON u.uid = ur.requestee_id) INNER JOIN {user_relationship_types} urt ON ur.rtid = urt.rtid WHERE ur.requester_id = %d AND urt.name = '%s' ORDER BY ur.rid", $user->uid, 'subscription');
        $items = array();
        while ($subscription = db_fetch_object($result)) {
          $items[] = l('[x]', 'logger/remove/'. $subscription->rid, array('attributes' => array('title' => "unsubscribe from ". $subscription->name ."'s stream"), 'query' => $destination, 'alias' => TRUE)) .' '. l($subscription->name, 'user/'. $subscription->uid, array('alias' => FALSE));
        }
        $block['subject'] = t('Subscriptions');
        $block['content'] = theme('logger_item_list', $items);
      }

      elseif ($delta == 'fluksonians' && user_access('logger')) {
        // list all users having the fluksionian role for now
        // to be replaced by a real buddylist later on
        $result = db_query("SELECT u.uid, u.name FROM ({users} u INNER JOIN {users_roles} ur ON u.uid = ur.uid) INNER JOIN {role} r ON ur.rid = r.rid WHERE r.name = '%s' AND NOT u.uid = %d ORDER BY u.name", 'fluksonian', $user->uid);
        $items = array();
        while ($fluksonian = db_fetch_object($result)) {
          $items[] = l('[+]', 'logger/add/'. $fluksonian->uid, array('attributes' => array('title' => "subscribe to ". $fluksonian->name ."'s stream"), 'query' => $destination, 'alias' => TRUE)) .' '. l($fluksonian->name, 'user/'. $fluksonian->uid, array('alias' => FALSE));
        }
        $block['subject'] = t('Fluksonians');
        $block['content'] = theme('logger_item_list', $items);
      }

      elseif ($delta == 'unit' && user_access('logger')) {
        //hardcoded the type and function parameters for now
        $unit = db_result(db_query("SELECT unit FROM {logger_meters} WHERE uid = %d AND type = '%s' AND function = '%s'", $user->uid, 'electricity', 'main'));
        $items = array();
        switch ($unit) {
          case 'watt':
            $items[] = 'watt';
            $items[] = l('kWh/year', 'logger/unit/kwh', array('attributes' => array('title' => "switch to kWh/year"), 'query' => $destination, 'alias' => TRUE));
            $items[] = l('euro/year [@ 0.18eur/kWh]', 'logger/unit/eur', array('attributes' => array('title' => "switch to euro/year"), 'query' => $destination, 'alias' => TRUE));
            $items[] = l('aud/year [@ 0.19aud/kWh]', 'logger/unit/aud', array('attributes' => array('title' => "switch to aud/year"), 'query' => $destination, 'alias' => TRUE));
            break;
          case 'kwh':
            $items[] = l('watt', 'logger/unit/watt', array('attributes' => array('title' => "switch to watt"), 'query' => $destination, 'alias' => TRUE));
            $items[] = 'kWh/year';
            $items[] = l('euro/year [@ 0.18eur/kWh]', 'logger/unit/eur', array('attributes' => array('title' => "switch to euro/year"), 'query' => $destination, 'alias' => TRUE));
            $items[] = l('aud/year [@ 0.19aud/kWh]', 'logger/unit/aud', array('attributes' => array('title' => "switch to aud/year"), 'query' => $destination, 'alias' => TRUE));
            break;
          case 'eur':
            $items[] = l('watt', 'logger/unit/watt', array('attributes' => array('title' => "switch to watt"), 'query' => $destination, 'alias' => TRUE));
            $items[] = l('kWh/year', 'logger/unit/kwh', array('attributes' => array('title' => "switch to kWh/year"), 'query' => $destination, 'alias' => TRUE));
            $items[] = 'euro/year [@ 0.18eur/kWh]';
            $items[] = l('aud/year [@ 0.19aud/kWh]', 'logger/unit/aud', array('attributes' => array('title' => "switch to aud/year"), 'query' => $destination, 'alias' => TRUE));
            break;
          case 'aud':
            $items[] = l('watt', 'logger/unit/watt', array('attributes' => array('title' => "switch to watt"), 'query' => $destination, 'alias' => TRUE));
            $items[] = l('kWh/year', 'logger/unit/kwh', array('attributes' => array('title' => "switch to kWh/year"), 'query' => $destination, 'alias' => TRUE));
            $items[] = l('euro/year [@ 0.18eur/kWh]', 'logger/unit/eur', array('attributes' => array('title' => "switch to euro/year"), 'query' => $destination, 'alias' => TRUE));
            $items[] = 'aud/year [@ 0.19aud/kWh]';
            break;
        }
        $block['subject'] = t('Unit');
        $block['content'] = theme('logger_item_list', $items);
      }

      elseif ($delta == 'publish' && user_access('logger')) {
        // $block['subject'] = t('Publish');
        $block['content'] = drupal_get_form('_logger_publish_form');
      }

      return $block;
  }
}

/**
 * Implementing a simple non-bulleted list for the logger_block
 */
function theme_logger_item_list($items, $title = NULL) {
  $output = '';
  foreach ($items as $item) {
    $output .= $item .'<br />';
  }
  return $output;
}

/**
 * Generates the publish block form.
 */
function _logger_publish_form() {
  $form['publish'] = array(
    '#type' => 'fieldset',
    '#title' => t('Publish'),
    '#description' => t('Publish the chart.'),
    '#collapsible' => TRUE,
    '#collapsed' => TRUE
  );
  $form['publish']['title'] = array(
    '#type' => 'textfield',
    '#title' => t('Title'),
    '#description' => t('Please enter the title of your post.')
  );
  $form['publish']['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Publish')
  );
  return $form;
}

/**
 * Process publish form submissions.
 */
function _logger_publish_form_submit($form, &$form_state) {
  $form_state['redirect'] = 'node/add';  //placeholder; check whether we can automatically fill in the new content type
}

/**
 * Define the administration settings form for the logger module
 */
function _logger_admin_settings() {
//TODO
}

/**
 * Implementation of hook_cron().
 * Cron will call this hook periodically [e.g. 1 hour interval] to perform housekeeping on the png's.
 */
function logger_cron() {
  exec('rm sites/all/modules/logger/graphs/hour/*');
  exec('rm sites/all/modules/logger/graphs/day/*');
  exec('rm sites/all/modules/logger/graphs/month/*');
  exec('rm sites/all/modules/logger/graphs/year/*');
  exec('rm sites/all/modules/logger/graphs/night/*');
}