<?php
// $Id: watchdog_triggers.module,v 1.1 2010-11-09 19:29:47 bastlynn Exp $

/**
 * @file
 * Provides a Trigger and Action integration for watchdog events.
 */

/**
 * Implementation of hook_hook_info().
 *
 * Register triggered hooks used by this module.
 */
function watchdog_triggers_hook_info() {
  return array(
    'watchdog_triggers' => array(
      'watchdog_triggers' => array(
        'watchdog_logged' => array(
          'runs when' => t('Watchdog logs an event'),
        ),
      ),
    ),
  );
}

/**
 * Implementation of hook_watchdog_triggers().
 */
function watchdog_triggers_watchdog_triggers($op, $user) {
  if (!in_array($op, array('watchdog_logged'))) {
    return;
  }
  $aids = _trigger_get_hook_aids('watchdog_triggers', $op);
  $context = array(
    'hook' => 'watchdog_triggers',
    'op' => $op,
    'user' => $user,
  );
  actions_do(array_keys($aids), $user, $context);
}

/**
 * Implementation of hook_action_info_alter().
 */
function watchdog_triggers_action_info_alter(&$info) {
  foreach ($info as $type => $data) {
    if (stripos($type, "user_") === 0 || stripos($type, "system_") === 0) {
      if (isset($info[$type]['hooks']['application'])) {
        $info[$type]['hooks']['watchdog_triggers'] = array_merge($info[$type]['hooks']['watchdog_triggers'], array('watchdog_logged'));
      }
      else {
        $info[$type]['hooks']['watchdog_triggers'] = array('watchdog_logged');
      }
    }
  }
}

/**
 * Implementation of hook_watchdog().
 */
function watchdog_triggers_watchdog($watchdog_message) {
  global $user;

  $types = trim(variable_get('watchdog_triggers_type', ''));
  $users = trim(variable_get('watchdog_triggers_user', ''));
  $request_uris = trim(variable_get('watchdog_triggers_request_uri', ''));
  $referers = trim(variable_get('watchdog_triggers_referer', ''));
  $ips = trim(variable_get('watchdog_triggers_ip', ''));
  $severities = variable_get('watchdog_triggers_severity',  array(WATCHDOG_CRITICAL, WATCHDOG_ALERT, WATCHDOG_EMERG));
  if (array_key_exists('-100', $severities)) {
    unset($severities['-100']);
  }
  if ($found_key = array_search('-100', $severities)) {
    unset($severities[$found_key]);
  }
  $messages = trim(variable_get('watchdog_triggers_message', ''));

  // Check each value.
  // These are cumulative filters, so if one fails - all fail.
  $triggered = TRUE;

  if (!empty($types)) {
    $types = _watchdog_triggers_clean_array(explode(',', $types));
    if (!in_array($watchdog_message['type'], $types)) {
      $triggered = FALSE;
    }
  }

  if (!empty($users)) {
    $users = _watchdog_triggers_clean_array(explode(',', $users));
    if (!in_array($watchdog_message['user']->name, $users)) {
      $triggered = FALSE;
    }
  }
  if (!empty($request_uris)) {
    $request_uris = _watchdog_triggers_clean_array(explode(',', $request_uris));
    $match_results = _watchdog_triggers_preg_match_patterns($request_uris, $watchdog_message['request_uri']);
    if ($match_results == FALSE) {
      $triggered = FALSE;
    }
  }
  if (!empty($referers)) {
    $referers = _watchdog_triggers_clean_array(explode(',', $referers));
    $match_results = _watchdog_triggers_preg_match_patterns($referers, $watchdog_message['referer']);
    if ($match_results == FALSE) {
      $triggered = FALSE;
    }
  }
  if (!empty($ips)) {
    $ips = _watchdog_triggers_clean_array(explode(',', $ips));
    $match_results = _watchdog_triggers_preg_match_patterns($ips, $watchdog_message['ip']);
    if ($match_results == FALSE) {
      $triggered = FALSE;
    }
  }
  if (count($severities) > 0) {
    $severities = _watchdog_triggers_clean_array($severities);
    if (!in_array($watchdog_message['severity'], $severities)) {
      $triggered = FALSE;
    }
  }
  if (!empty($messages)) {
    $messages = _watchdog_triggers_clean_array(explode(',', $messages));
    $match_results = _watchdog_triggers_preg_match_patterns($messages, $watchdog_message['message']);
    if ($match_results == FALSE) {
      $triggered = FALSE;
    }
  }

  if ($triggered === TRUE) {
    module_invoke_all('watchdog_triggers', 'watchdog_logged', $user);
  }
}

/**
 * Implementation of hook_menu_alter().
 *
 * Work around loss of menu local task inheritance.
 */
function onthisdate_menu_alter(&$callbacks) {
  if (module_exists('trigger') & isset($callbacks['admin/build/trigger/watchdog_triggers'])) {
    $callbacks['admin/build/trigger/watchdog_triggers']['access callback'] = 'trigger_access_check';
  }
}

/**
 * Implementation of hook_perm().
 */
function watchdog_triggers_perm() {
  return array(
    'administer watchdog triggers',
  );
}

/**
 * Implementation of hook_menu().
 */
function watchdog_triggers_menu() {
  $items = array();
  $items['admin/settings/watchdog_triggers'] = array(
    'title' => t('Watchdog triggers'),
    'description' => t('Configure watchdog triggers settings'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('watchdog_triggers_admin_settings'),
    'access arguments' => array('administer watchdog triggers'),
  );

  return $items;
}

/**
 * Implements form page callback for module admin settings page
 */
function watchdog_triggers_admin_settings() {
  $form = array();
  // Check against the following features of watchdog.
  $form['watchdog_triggers_info'] = array(
    '#type' => 'item',
    '#description' => t('The settings set here apply to all watchdog actions. These are cumulative filters. '.
    'The more filters you set the narrower your selection of watchdog events will be. If you need more fine '.
    'control or multiple configurations then you need to upgrade to the Rules integration for Watchdog.'),
  );

  // type (module name)
  $form['watchdog_triggers_type'] = array(
    '#type' => 'textarea',
    '#title' => t('Message type'),
    '#default_value' => variable_get('watchdog_triggers_type', ''),
    '#description' => t('Enter each type to trigger against, usually the module of origin, separated by a comma.'),
  );

  // user
  $form['watchdog_triggers_user'] = array(
    '#type' => 'textarea',
    '#title' => t('User generating message'),
    '#default_value' => variable_get('watchdog_triggers_user', ''),
    '#description' => t('Enter each user name to trigger against, separated by a comma.'),
  );

  // request uri
  $form['watchdog_triggers_request_uri'] = array(
    '#type' => 'textarea',
    '#title' => t('Message request uri'),
    '#default_value' => variable_get('watchdog_triggers_request_uri', ''),
    '#description' => t('Enter each regular expression to match the requesting uri against, separated by a comma.'),
  );

  // referer
  $form['watchdog_triggers_referer'] = array(
    '#type' => 'textarea',
    '#title' => t('Message referer'),
    '#default_value' => variable_get('watchdog_triggers_referer', ''),
    '#description' => t('Enter each regular expression to match the refering page against, separated by a comma.'),
  );

  // ip
  $form['watchdog_triggers_ip'] = array(
    '#type' => 'textarea',
    '#title' => t('IP generating message'),
    '#default_value' => variable_get('watchdog_triggers_ip', ''),
    '#description' => t('Enter each regular expression to match the IP against, separated by a comma.'),
  );

  // severity
  $array_options = array(
    -100 => 'none',
    WATCHDOG_EMERG => 'Emergency: system is unusable',
    WATCHDOG_ALERT => 'Alert: action must be taken immediately',
    WATCHDOG_CRITICAL => 'Critical: critical conditions',
    WATCHDOG_ERROR => 'Error: error conditions',
    WATCHDOG_WARNING => 'Warning: warning conditions',
    WATCHDOG_NOTICE => 'Notice: normal but significant condition',
    WATCHDOG_INFO => 'Informational: informational messages',
    WATCHDOG_DEBUG => 'Debug: debug-level messages',
  );

  $form['watchdog_triggers_severity'] = array(
    '#type' => 'select',
    '#title' => t('Message severity'),
    '#default_value' => variable_get('watchdog_triggers_severity', array(WATCHDOG_CRITICAL, WATCHDOG_ALERT, WATCHDOG_EMERG)),
    '#options' => $array_options,
    '#description' => t('Select each severity to trigger against.'),
    '#multiple' => TRUE,
  );

  // message
  $form['watchdog_triggers_message'] = array(
    '#type' => 'textarea',
    '#title' => t('Message pattern'),
    '#default_value' => variable_get('watchdog_triggers_message', ''),
    '#description' => t('Enter each regular expression to match the message against, separated by a comma.'),
  );

  return system_settings_form($form);
}

/**
 * Helper function, prepares user data in an array for matching.
 */
function _watchdog_triggers_clean_array($this_array) {
  foreach ($this_array as $key => $value) {
    $this_array[$key] = trim($value);
  }
  return $this_array;
}

/**
 * Helper function, preg_matches contents of an array.
 */
function _watchdog_triggers_preg_match_patterns($array, $target) {
  $match_results = FALSE;
  foreach ($array as $pattern) {
    $pattern = trim($pattern);
    $matches = array();
    if (!empty($pattern)) {
      $number_matches = preg_match_all($pattern, $target, $matches);
      if ($number_matches > 0 && $number_matches !== FALSE) {
        $match_results = TRUE;
      }
    }
  }
  return $match_results;
}