<?php
/**
* Implementation of hook_rules_action_info().
* @ingroup rules
*/
function user_conditions_rules_action_info() {
  return array(
    'user_conditions_action_send_mail' => array(
      'label' => t('Send an email to all other comment posters and the author of a node'),
      'arguments' => array(
        'node' => array('type' => 'node', 'label' => t('The node to which the published comment has been added')),
        'comment' => array('type' => 'comment', 'label' => t('The comment that has just been published')),
        'author' => array('type' => 'user', 'label' => t('The author of the published comment')),
      ),
      'module' => 'Comment',
    ),
  );
}

function user_conditions_action_send_mail($node, $comment, $author, $settings) {
  $sql = 'SELECT uid FROM {comments} WHERE nid = ' . $comment->nid . ' AND uid != ' . $comment->uid . ' GROUP BY (uid)';
  $query = db_query($sql);
  
  $uids = array();
  if ( $query !== FALSE && db_affected_rows() ) {
  	while( ($obj = db_fetch_object($query)) !== FALSE) {
      $uids[] = $obj->uid;
  	}
  }
  
  if ( $node->uid != $author->uid ) {
    $uids[] = $node->uid;
  }
  
  $uids = array_unique($uids);

  if ( !empty($uids)) {
    foreach($uids as $uid) {
      $account = user_load($uid);
    
      if ( $account !== FALSE ) {
        $from = isset($settings['from']) ? $settings['from'] : NULL;
        $params['account'] = $account;
        $params['comment'] = $comment;
        $params['node'] = $node;
        $params['settings'] = $settings;
        
        drupal_mail('user_conditions', 'comment_published', $account->mail, user_preferred_language($account), $params, $from);
      }
    }
  }
}
?>