trackback.module

<?php
define('TRACKBACK_WITH_SPAM', FALSE);

define('TRACKBACK_STATUS_UNPUBLISHED', 0);
define('TRACKBACK_STATUS_PUBLISHED',   1);
define('TRACKBACK_STATUS_SPAM_UNSURE', 2);
define('TRACKBACK_STATUS_SPAM',        3);

/**
 * Implementation of hook_theme()
 */
function trackback_theme() {
  return array(
    'trackback' => array(
      'arguments' => array('trackback' => NULL)
    ),
    'trackbacks' => array(
      'arguments' => array('trackbacks' => NULL)
    ),
    'trackback_url' => array(
      'arguments' => array('url' => NULL, 'node' => NULL, 'inblock' => NULL)
    ),
    'trackback_admin_table' => array(
      'arguments' => array('form' => NULL)
    )
  );
}

function theme_trackback($trackback, $inblock) {
  drupal_add_css(drupal_get_path('module', 'trackback') .'/trackback.css');

  $output = '';
  if ($inblock) {
    $options = variable_get('trackback_block_display_options', array('excerpt'));
    $output .= '<div class="trackback" id="trackback-'. $trackback->trid .'">'."\n";
    $options['attributes'] = array(
      'title' => t('Read post "%postname" from %sitename', array('%sitename' => $trackback->name, '%postname' => $trackback->subject))
    );
    
    $output .= '<span class="trackback-title">'. l($trackback->subject, $trackback->url, $options) .'</span>'."\n";
    
    if (!empty($options['created'])) {
      $output .= '<span class="trackback-created">'. t('from %sitename on @date', array('%sitename' => $trackback->name, '@date' => format_date($trackback->created))) .'</span>'."\n";
    } else {
      $output .= '<span class="trackback-created">'. t('from %sitename', array('%sitename' => $trackback->name)) .'</span>'."\n";
    }    
    if (!empty($options['excerpt'])) {
      $output .= '<div class="excerpt">'. check_markup($trackback->excerpt .'[..]') .'</div>'."\n";
    }
    if (!empty($options['site'])) {
      $output .= '<span class="trackback-site">'. t('IP Address: %ip', array('%ip' => $trackback->site)) .'</span>'."\n";
    }
    $output .= '</div>'."\n";
  }
  else {
    $output  = '<div class="trackback" id="trackback-'. $trackback->trid .'">'."\n";
    $output .= '<h3 class="title">'. l($trackback->subject, $trackback->url) .'</h3>'."\n";
    $output .= '<span class="submitted">'. t('from %sitename on @date', array('%sitename' => $trackback->name, '@date' => format_date($trackback->created))) .'</span>'."\n";
    $output .= '<div class="content">'. check_markup($trackback->excerpt) .'</div>'."\n";
    if ($links) {
      $output .= '<div class="links">'. theme('links', $links) .'</div>'."\n";
    }
    $output .= '</div>'."\n";
  }
  return $output;
}


function theme_trackbacks($trackbacks, $inblock) {
  if (count($trackbacks) == 0)
    return;
  
  $output = '';
  
  if ($inblock) {
    if (count($trackbacks) == 0) {
      $output = t('No Trackbacks received');
    }
    else {
      $output = theme('item_list', $trackbacks, NULL, 'ul', array('class' => 'trackback-block-list'));
    }
  }
  else {
    $output = 'aaaa';
  }
  return $output;
}

function theme_trackback_url($url, &$node, $inblock = FALSE) {
  if ($inblock) {
    $options['attributes'] = array(
      'class' => 'trackback-url',
      'title' => t('Trackback URL for "%nodetitle"', array('%nodetitle' => $node->title))
    ); 
    return l(t('Trackback-URL'), $url, $options);
  }
  else
    return '<div class="trackback-url">'. theme('box',  t('Trackback URL for "%nodetitle"', array('%nodetitle' => $node->title)), $url) .'</div>';
}

/**
 * Invoke a hook_trackback() operation in all modules.
 *
 * @param &$trackback
 *   A trackback object.
 * @param $op
 *   A string containing the name of the trackback operation.
 *   - received   : the trackback have been received, not already stored into DB ($trackback->trid is NULL)
 *                  modules can set "status" and "status_log" to something useful (see TRACKBACK_STATUS_xxxx defines)
 *   - inserted   : the trackback have been saved into DB (modules can use $trackback->trid value)

 *   - published  : the trackback have been published
 *   - mark-spam  : the trackback have been marked as SPAM content
 *   - unmark-spam: the trackback have been un-marked from beening SPAM
 *   - unpublished: the trackback have been un-published
 *   - deleted    : the trackback have been deleted (the Trackback Object is only for read)
 *
 *   - sent       : a pingback have been sent
 *
 *   - spam-filtering : a module should present himself for SPAM filtering returning a 'modulename' => TRUE
 *
 * @return
 *   The returned value of the invoked hooks.
 */

function trackback_invoke_trackback($op, &$trackback) {
  $return = array();
  foreach (module_implements('trackback') as $name) {
    $function = $name .'_trackback';
    $result = $function($op, $trackback);
    //print __function__ . " --- $function($op) : ". var_export($result, TRUE). "\n"; 
    
    if (isset($result)) {
      if (is_array($result)) {
        $return = array_merge($return, $result);
      }
      else {
        $return[$name] = $result;
      }
    }
  }
  return $return;
}

function trackback_render_received(&$node, $inblock = FALSE) {
  $trackbacks = trackback_get_received($node);
  
  // drupal_setdrupal_set_message(__function__ . var_export($trackbacks, TRUE));
  $received = array();
  foreach ($trackbacks as $trackback) {
    $received[] = theme('trackback', $trackback, $inblock);
  }
  return theme('trackbacks', $received, $inblock);
}

/**
 * Implementation of hook_node_type()
 */
function trackback_node_type($op, $info) {
  switch($op) {
    case 'update':
      if (!empty($info->old_type) && $info->old_type != $info->type && trackback_nodetypes_enabled($info->old_type)) {
        // drupal_set_message(__function__ .'('. $op. ')');
        trackback_nodetypes_enabled($info->old_type, 'delete');
        trackback_nodetypes_enabled($info->type, 'add');
      }
      break;
    case 'delete':
      if (trackback_nodetypes_enabled($info->type)) {
        // drupal_set_message(__function__ .'('. $op. ')');
        trackback_nodetypes_enabled($info->type, 'delete');
        
        // @TODO: delete all trackbacks for deleted nodetypes!!!
        trackback_delete_trackbacks_nodetype($info->type);
      }
      break;
  }
}

/**
 * Adding/removing trackback for nodetypes
 */
function trackback_node_type_form_submit(&$form, $form_state) {
  $type = $form_state['values']['type'];
  if (trackback_nodetypes_enabled($type) != $form_state['values']['trackback']) {
    trackback_nodetypes_enabled($type, $form_state['values']['trackback'] == 1 ? 'add' : 'delete');
  }
  return;
}

/**
 * Implementation of hook_form_alter()
 */
function trackback_form_alter(&$form, $form_state, $form_id) {
  // Add settings for node_type edit form
  if ($form_id == 'node_type_form') {
    $form['workflow']['trackback'] = array(
      '#type' => 'checkbox',
      '#title' => t('Enable receiving Trackbacks'),
      '#default_value' => trackback_nodetypes_enabled($form['#node_type']->type),
      '#description' => t('Enable trackbacks for this node type.')
    );
    $form['#submit'][] = 'trackback_node_type_form_submit';
  }

  // Add trackback settings on node creation/edit form
  else if (isset($form['type']) && $form['type']['#value'] .'_node_form' == $form_id) {
    $node = $form['#node'];
    
    if (trackback_nodetypes_enabled($node->type)) {
      // drupal_set_message(__function__);
      $form['trackback'] = array(
        '#type' => 'fieldset',
        '#title' => t('Trackbacks'),
        '#collapsible' => TRUE,
        '#collapsed' => !isset($node->trackback_urls),
      );
      
      if (user_access('change node trackback setting')) {
        $form['trackback']['trackback_can_receive'] = array(
          '#type' => 'checkbox',
          '#title' => t('Enable incoming Trackbacks'),
          '#default_value' => isset($node->trackback_can_receive) ? $node->trackback_can_receive : 1,
          '#description' => t('Allow other posts to send trackbacks to this content.')
        );
      }
      else {
        $form['trackback']['trackback_can_receive'] = array(
          '#type' => 'value',
          '#value' => isset($node->trackback_can_receive) ? $node->trackback_can_receive : 1,
        );
      }
      
      if (variable_get('trackback_auto_detection', 'auto') == 'user') {
        $form['trackback']['trackback_urls'] = array(
          '#type' => 'textarea',
          '#title' => t('Send Trackbacks'),
          '#default_value' => isset($node->trackback_urls) ? $node->trackback_urls : '',
          '#cols' => 80,
          '#rows' => 4,
          '#description' => t('Enter one URL per line for each trackback you wish to send.'),
          '#wysiwyg' => FALSE,
        );
      }
      // if there are any past successful trackbacks from this posting, add them to the node editing page.
      // if there are any past unsuccessful trackbacks from this posting, add checkmarks to enable resending them
      $past_successes_listing = array();
      $options = array();
      if (isset($node->nid)) {
        $sent_ok = trackback_get_sent($node, 'successful');
        if (count($sent_ok)) {
          $sent = array();
          foreach($sent_ok as $s) {
            $sent[$s] = $s;
          }
          // drupal_set_message(var_export($sent, TRUE));
          $form['trackback']['trackbacks_urls'] = array(
            '#type' => 'checkboxes',
            '#title' => t('Successful sent URLs'),
            '#disabled' => 'disabled',
            '#default_value' => array_keys($sent),
            '#options' => $sent,
          );          
        }
        
        if (TRUE || variable_get('trackback_auto_detection', 'auto') == 'user') {
          $sent_err = trackback_get_sent($node, 'error');
          // add listing of unsuccessfully trackbacked URLs
          if (count($sent_err)) {
            $sent = array();
            foreach($sent_err as $s) {
              $sent[$s] = $s;
            }
            $form['trackback']['trackback_urls_to_retry'] = array(
              '#type' => 'checkboxes',
              '#title' => t('Unsuccessful URLs'),
              '#default_value' => array(),
              '#options' => $sent,
              '#description' => t('Attempts to ping these URLs with this post have failed. Mark a check next to the trackback URLs you wish to retry for this post.')
            );
          }
        }
      }
    }
  }
}

/*
function trackback_link($type, $node = NULL, $teaser = FALSE) {
  $links = array();
  switch ($type) {
    case 'node':
      if (isset($node->can_receive)) {
        if (variable_get('trackback_display_url', 'default') == 'links' ||
          (!$teaser && variable_get('trackback_display_url', 'default') == 'links-full') ||
          ($teaser && variable_get('trackback_display_url', 'default') == 'links-teaser')) {
          $links['trackback-url'] = array(
            'title' => t('Trackback URL'),
            'href' => trackback_get_url($node),
            'attributes' => array('title' => t('Trackback URL for "%nodetitle"', array('%nodetitle' => $node->title))),
          );
        }
        if ($teaser && variable_get('trackback_links_count_display', 1) == 1) {
          $count = db_result(db_query("SELECT count(*) FROM {trackback_received} WHERE nid=%d AND status=1", $node->nid));
          if ($count) {
            $links['trackback_trackbacks'] = array(
              'title' => format_plural($count, '1 trackback', '@count trackbacks'),
              'href' => _trackback_path($node),
            );
            // Don't display fragment if trackbacks are displayed on a separate page
            if (variable_get('trackback_view', 0) != 1)
              $links['trackback_trackbacks']['fragment'] = 'trackbacks';
          }
        }
      }   
      break;

    case 'trackback':
      if (!$teaser) {
        $links['trackback_edit'] = array(
          'title' => t('edit'),
          'href' => 'trackback/edit/'. $node->trid
        );
      }
      $links['trackback_delete'] = array(
        'title' => t('delete'),
        'href' => 'trackback/delete/'. $node->trid
      );
      if (TRACKBACK_WITH_SPAM) {
        $links += _trackback_spam_link($node);
      }
      break;
  }
  return $links;
}
*/

/**
 * hook_menu() callback
 */
function trackback_menu() {
  // drupal_set_message(__function__);
  $items['admin/content/trackback'] = array(
    'title' => 'Trackbacks',
    'description' => 'List and edit site trackbacks and the trackback moderation queue.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('trackback_admin_overview'),
    'access arguments' => array('administer trackbacks'),
    'file' => 'trackback.admin.inc'
  );

  // Tabs:
  $items['admin/content/trackback/list'] = array(
    'title' => 'List',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10
  );

  // Subtabs:
  $items['admin/content/trackback/list/published'] = array(
    'title' => 'Published trackbacks',
    'access arguments' => array('administer trackbacks'),    
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10
  );
  $items['admin/content/trackback/list/approval'] = array(
    'title' => 'Approval queue',
    'page arguments' => array('trackback_admin_overview', 'approval'),
    'access arguments' => array('administer trackbacks'),
    'type' => MENU_LOCAL_TASK
  );
  
  $items['admin/content/trackback/list/spam'] = array(
    'title' => 'Spam',
    'page arguments' => array('trackback_admin_overview', 'spam'),
    'access arguments' => array('administer trackbacks'),
    'weight' => 10,
    'type' => MENU_LOCAL_TASK
  );
  $items['admin/content/trackback/settings'] = array(
    'title' => 'Settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('trackback_config_form'),
    'access arguments' => array('administer trackbacks'),
    'weight' => 10,
    'type' => MENU_LOCAL_TASK,
    'file' => 'trackback.admin.inc'
  );

  // Other stuff:
  $items['trackback/%node'] = array(
    'title' => 'Trackbacks',
    'page callback' => '_trackback_receive_post',
    'page arguments' => array(1),
    'access arguments' => array('access content'),
    'access callback' => '_trackback_access',
    'access arguments' => array('receive', 1),
    'type' => MENU_CALLBACK,
    'file' => 'trackback-receive.inc'
  );    
  $items['trackback/edit/%trackback'] = array(
    'title' => 'Moderate trackback',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('trackback_edit_form', 2),
    'access callback' => '_trackback_access',
    'access arguments' => array('edit', NULL, 2),
    'type' => MENU_CALLBACK,
    'file' => 'trackback.admin.inc'
  );
  $items['trackback/delete/%trackback'] = array(
    'title' => 'Delete trackback',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('trackback_delete_form', 2),
    'access callback' => '_trackback_access',
    'access arguments' => array('edit', NULL, 2),
    'type' => MENU_CALLBACK,
    'file' => 'trackback.admin.inc'
  );
  /*
  $items['node/%node/trackback'] = array(
    'title' => 'Trackbacks',
    'page callback' => 'trackback_view_page',
    'page arguments' => array(1),
    'access callback' => '_trackback_access',
    'access arguments' => array('page', 1),
    'weight' => 2,
    'type' => MENU_LOCAL_TASK
  );
  */
  return $items;
}

/**
 * hook_perm() callback
 */

function trackback_perm() {
  return array(
    'administer trackbacks',
    'change node trackback setting',
  );
}


function _trackback_access($op, $node, $trackback = NULL) {
  // drupal_set_message(__function__ .'('.$op.')');
  // print __function__ .'('.$op.')';
  switch ($op) {
    case 'page':
      // drupal_set_message(__function__ . var_export($node->trackback_can_receive, TRUE));
      return $node->trackback_can_receive && variable_get('trackback_view', 0) == 1 && node_access('view', $node) && db_result(db_query('SELECT count(*) FROM {trackback_received} WHERE nid=%d AND status=1', $node->nid));
    case 'edit':
      if (user_access('administer trackbacks')) {
        return TRUE;
      }
      if (empty($node) && !empty($trackback->nid)) {
        $node = node_load($trackback->nid);
      }
      return node_access('update', $node);
    case 'receive':
      if (variable_get('trackback_receive_post', TRUE) == TRUE)
        return $node->trackback_can_receive && node_access('view', $node);
      else
        return FALSE;
  }
}

/*

function trackback_view_page($node) {
  drupal_set_title(check_plain($node->title));
  return trackback_render_received($node);
}

*/

/**
 * hook_cron() callback
 */
 /*
function trackback_cron() {
  // query for all nodes where
  $result = db_query('SELECT t.nid, n.status FROM {trackback_node} t INNER JOIN {node} n ON t.nid = n.nid WHERE t.awaiting_cron = 1');

  while ($node = db_fetch_object($result)) {
    // First things first, let's unset the 'awaiting_cron' bit in the {trackback_node} table.
    db_query('UPDATE {trackback_node} SET awaiting_cron = 0 WHERE nid = %d', $node->nid);
    if ($node->status) {
      module_load_include('inc', 'trackback', 'trackback.ping');
      $node = node_load($node->nid);
      _trackback_ping($node, trackback_urls_via_nodebody($node));
    }
  }
}
*/

/*
function _trackback_valid_url($url) {
  $uc = '[a-z0-9;/?:@&=+$,_.!~*\'()%-]';
  return preg_match('`^(http|https)://'. $uc .'+(#'. $uc .'*)?$`i', $url);
}
*/

/*
function _trackback_path($obj, $text = NULL, $opt = array()) {
  static $prefix;

  if (!isset($prefix)) {
    $prefix = variable_get('trackback_view', 0) == 1 ? '/trackback' : '';
  }
  if (!isset($text)) {
    return 'node/'. $obj->nid . $prefix;
  }
  if ($obj->status) {
    $opt += array('fragment' => 'trackback-'. $obj->trid);
    return l($text, 'node/'. $obj->nid . $prefix, $opt);
  }
  return l($text, 'trackback/edit/'. $obj->trid, $opt);
}
*/


function _trackback_build_content($node, $teaser = FALSE) {
  unset($node->trackback_can_receive);
  return node_build_content($node, $teaser);
}


/**
 * Master function for Trackback management
 * @param <type> $op
 * @param <type> $trackback
 */
function trackback_do($op, &$trackback, $cacheclear = FALSE) {
  $operated = NULL;
  $result = FALSE;
  
  if (is_numeric($trackback)) {
    $trackback = trackback_load($trackback);
  }

  if (is_object($trackback)) {
    switch ($op) {
      case 'publish':
        $trackback->status = TRACKBACK_STATUS_PUBLISHED;
        $result = _trackback_do_update($trackback);
        $operated = 'published';
        break;

      case 'unpublish':
        $trackback->status = TRACKBACK_STATUS_UNPUBLISHED;
        $result = _trackback_do_update($trackback);
        $operated = 'unpublished';
        break;
      
      case 'mark-spam':
        $trackback->status = TRACKBACK_STATUS_SPAM;
        $result = _trackback_do_save($trackback);
        $operated = 'mark-spam';
        break;

      case 'unmark-spam':
        // What are we gonna do here???
        $operated = 'unmark-spam';
        break;

      case 'delete':
        $result = _trackback_do_delete($trackback);
        $operated = 'deleted';
        break;

      default:
        drupal_set_message(t('Trackback Operation %op not implemented', array('%op' => $op)));

   }

   trackback_invoke_trackback($operated, $trackback);
   if ($clearcache) {
    cache_clear_all();
   }
   return $result;
  }
  else {
    return FALSE;
  }
}
/*
function _trackback_operation($action, $trackback, $clear = TRUE) {
  if (is_numeric($trackback)) {
    $trackback = trackback_load($trackback);
  }
  if ($trackback) {
    switch ($action) {
      case 'publish':
        db_query('UPDATE {trackback_received} SET status=1 WHERE trid=%d', $trackback->trid);
        $trackback->status = 1;
        trackback_invoke_trackback($trackback, $action);
        watchdog('trackback', 'Published trackback %subject.', array('%subject' => $trackback->subject), WATCHDOG_NOTICE, _trackback_path($trackback, t('view')));
        break;

      case 'unpublish':
        db_query('UPDATE {trackback_received} SET status=0 WHERE trid=%d', $trackback->trid);
        $trackback->status = 0;
        trackback_invoke_trackback($trackback, $action);
        watchdog('trackback', 'Unpublished trackback %subject.', array('%subject' => $trackback->subject), WATCHDOG_NOTICE, _trackback_path($trackback, t('view')));
        break;

      case 'delete':
        db_query('DELETE FROM {trackback_received} WHERE trid=%d', $trackback->trid);
        trackback_invoke_trackback($trackback, $action);
        watchdog('trackback', 'Deleted trackback %subject. The trackback was posted to !link.', array('%subject' => $trackback->subject, '!link' => l(url('node/'. $trackback->nid, array('absolute' => TRUE)), 'node/'. $trackback->nid)));
        break;

      default:
        $action($trackback);
        break;
    }
    if ($clear) {
      cache_clear_all();
    }
  }
  return $trackback;
}
*/


// ========================================================================================================================== 

/**
 * Implementation of hook_help().
 */
function trackback_help($path, $arg) {
  if ($path == 'admin/help#trackback') {
    module_load_include('inc', 'trackback', 'trackback.admin');
    return _trackback_help($path, $arg);
  }
}

/**
 * Returns if the given Node can receive trackbacks
 * @param $nid
 * @param $action in check, enable, disable, insert
 * @return
 */
function trackback_node_enabled($nid, $action = 'check') {
  // drupal_set_message(__function__ .'() : '. $action . '=>'.$nid);
  switch ($action) {
    case 'insert':
      db_query("INSERT INTO {trackback_node}(nid, awaiting_cron, can_receive) VALUES(%d, %d, %b)", $nid, 0, 1);
      return TRUE;
      break;
    
    case 'enable':
      db_query("UPDATE {trackback_node} SET can_receive = %b, awaiting_cron = %b WHERE nid = %d", 1, 1, $nid);
      return TRUE;
      break;
    
    case 'disable':
      db_query("UPDATE {trackback_node} SET can_receive = %b, awaiting_cron = %b WHERE nid = %d", 0, 0, $nid);
      return TRUE;
      break;
    
    default:
      $sql = "SELECT can_receive FROM {trackback_node} WHERE nid=%d";
      return (boolean) db_result(db_query($sql, $nid));
      break;
  }
}


/**
 * Check if trackback is enabled for given NodeType
 * @param nodetype nodeType to check
 * @param action to do: check, add or delete
 * @return TRUE or FALSE
 */
function trackback_nodetypes_enabled($nodetype, $action = 'check') {
  // drupal_set_message(__function__ .'() : '. $action . '='.$nodetype);
  switch($action) {
    case 'check':
      return in_array($nodetype, variable_get('trackback_nodetypes', array()), TRUE);
      break;
      
    case 'delete':
      $types = variable_get('trackback_nodetypes', array());
      unset($types[$nodetype]);
      variable_set('trackback_nodetypes', $types);
      break;
      
    case 'add':
      $types = variable_get('trackback_nodetypes', array());
      $types[] = $nodetype;
      variable_set('trackback_nodetypes', $types);
      // @TODO: manage i18sync module view README in i18nsync
      /* More fields for a specific content type 'nodetype' only.
      $conf['i18nsync_fields_node_nodetype'] = array(
        'field3' => t('Field 3 name'),
          ...
        );
        */
      break;
      
    default:
      return FALSE;
  }
  return TRUE;
}

/**
 * Implementation of hook_xmlrpc()
 * Required by Pingback 1.0 specs (http://www.hixie.ch/specs/pingback/pingback)
 * Code taken from pingback.module
 */
function trackback_xmlrpc() {
  return array(array(
    'pingback.ping', // Method-Name (as in Pingback 1.0 specs)
    'trackback_receive_xmlrpc', // Function callback
    array( // Method Signature
      'string', // sourceURI 
      'string', // targetURI
      'string'  // return value
    ),
    t('Handles Trackbacks pings.'),
  ));
}

/**
 * XML-RPC callback: process pingback.ping() call.
 * @return xmlrpc server errors as for Pingback 1.0 specs (http://www.hixie.ch/specs/pingback/pingback)
 */
function trackback_receive_xmlrpc($sourceURI, $targetURI) {
  if (variable_get('trackback_receive_xmlrpc', FALSE)) {
    module_load_include('inc', 'trackback', 'trackback-receive');
    _trackback_receive_xmlrpc($sourceURI, $targetURI);
  }
  else
    return xmlrpc_server_error(33, t("The specified target URL cannot be used as a target. It either doesn't exist, or it is not a pingback-enabled resource."));
}

/**
 * Implementation of hook_nodeapi()
 * @TODO: review!!
 */
function trackback_nodeapi(&$node, $op, $teaser = NULL, $page = NULL) {
  // drupal_set_message(__function__ .'() : '.$op);
  if (!variable_get('trackback_receive_post', TRUE) && !variable_get('trackback_receive_xmlrpc', FALSE)) {
    // Trackback in't enabled!
    return;
  }
  
  if (!trackback_nodetypes_enabled($node->type)) {
    // This nodetype don't have Trackback enabled
    // @TODO: manage nodetype changing
    // @TODO: manage enable/disable nodetype deleting old trackbacks?
    return;
  }

  switch ($op) {
    // "load" : OK!
    case 'load':
      $can_receive = FALSE;
      if ($node->status) {
        $can_receive = trackback_node_enabled($node->nid);
      }
      // drupal_set_message(__function__ . var_export($can_receive, TRUE));
      return array('trackback_can_receive' => $can_receive);
      break;
    
    // "view": OK!
    case 'view':
      // If node can receive trackbacks and isn't in preview mode
      if (isset($node->trackback_can_receive) && empty($node->in_preview)) {
        // XMLRPC 
        if (variable_get('trackback_receive_xmlrpc', FALSE)) {
          // Insert pingback header when a node is being viewed.
          if (arg(0) == 'node' && is_numeric(arg(1)) && arg(3) == NULL) {
            drupal_set_header('X-Pingback: '. $GLOBALS['base_url'] .'/xmlrpc.php');
            // We should only send the HTTP header and not the <Link>?
            // drupal_add_link(array('rel' => $GLOBALS['base_url'] .'/xmlrpc.php'));
          }
        }

        // Trackback using POST/GET url
        if (variable_get('trackback_receive_post', TRUE)) {
          $node->content['trackback'] = array('#weight' => 12);
          $node->content['trackback']['rdf'] = array(
            '#value' => trackback_get_RDF($node),
            '#weight' => -1
          );            
          if (!$teaser && variable_get('trackback_display_url', 'innode') == 'innode') {            
            $node->content['trackback']['url'] = array(
              '#value' => theme('trackback_url', trackback_get_url($node), $node),
              '#weight' => 8,
            );
          }
        }
        if (!$teaser && variable_get('trackback_display_node', FALSE)) {
          $node->content['trackback']['received'] = array(
            '#value' => trackback_render_received($node),
            '#weight' => 7,
          );
        }
      }
      break;

    case 'validate':
      /*
      if (!empty($node->trackback_urls)) {
        foreach (explode("\n", $node->trackback_urls) as $url) {
          $url = trim($url);
          if ($url && !_trackback_valid_url($url)) {
            form_set_error('trackback_urls', t('The trackback url %url is not a valid url.', array('%url' => $url)));
          }
        }
      }
      */
      break;

    case 'insert':
      if (trackback_nodetypes_enabled($node->type)) {
        trackback_node_enabled($node->nid, 'insert');
        $set = ($node->trackback_can_receive && $node->status)? 'enable' : 'disable';
        if (isset($node->trackback_can_receive)) {
          trackback_node_enabled($node->nid, $set);
        }      
      }
      break;
        
    case 'update':
      $set = ($node->trackback_can_receive && $node->status)? 'enable' : 'disable';
      
      // drupal_set_message(__function__ .'() : SET='. $set);
      if (isset($node->trackback_can_receive)) {
        trackback_node_enabled($node->nid, $set);
      }
      if ($set == 'enable' && variable_get('trackback_sending', 'oncron') == 'onupdate') {
        // drupal_set_message(__function__ .'() : send?='. variable_get('trackback_sending', 'oncron'));
        // Add this node to the list of awaiting for ping..
        global $_trackback_ping_nid;
        if (variable_get('trackback_merge_within_translations', TRUE)) {
          // If we keep only the "original" source, send pingbacks only from original node?
          if (isset($node->tnid) && ($node->nid == $node->tnid)) {
            $_trackback_ping_nid[] = $node->tnid;
          }
        }
        else {
          $_trackback_ping_nid[] = $node->nid;
        }
        // drupal_set_message(__function__ .'() : GLOBAL='. var_export($_trackback_ping_nid, TRUE));
      }

      /*
        module_load_include('inc', 'trackback', 'trackback.ping');
        global $_trackback_ping_node;
        $_trackback_ping_node = drupal_clone($node);
        $cron = ($node->status && variable_get('trackback_auto_detection_enabled', 0) == 2);
        db_query("UPDATE {trackback_node} SET awaiting_cron=%d, can_receive=%d WHERE nid=%d", $cron, $node->can_receive, $node->nid);
        if (!db_affected_rows()) {
          db_query("INSERT INTO {trackback_node}(nid, awaiting_cron, can_receive) VALUES(%d, %d, %d)", $node->nid, $cron, $node->can_receive);
        }
        */
      
      
      break;

    case 'delete':
      trackback_delete_trackbacks($node->nid);
      break;
  }
}

/**
 *
 */
function trackback_exit() {
  global $_trackback_ping_nid;
  // drupal_set_message(__function__ .'() : GLOBAL='. var_export($_trackback_ping_nid, TRUE));
  if (!empty($_trackback_ping_nid)) {
    
    // If more than one, use a FIFO list and let cron ping the others!
    $first = array_shift($_trackback_ping_nid);
    if (!empty($_trackback_ping_nid)) {
      _trackback_enqueue($_trackback_ping_nid);
    }

    module_load_include('inc', 'trackback', 'trackback-send');
    _trackback_send($first);
  }
}

/**
 * @TODO:
 */
function _trackback_enqueue($nids) {
  drupal_set_message(__function__ .'() : NIDs='. var_export($nids, TRUE));
  return true;
}


/**
 * Handler function called when a trackback have been successfully received
 */
function trackback_received(&$trackback) {
  // print __function__ . "<br>\n";

  
  trackback_invoke_trackback('received', $trackback);
  
  if ($trackback->status == TRACKBACK_STATUS_SPAM && variable_get('trackback_spam_moderation', 'delete') == 'delete') {
    // Auto delete!
    watchdog('trackback', 'Auto-Deleted trackback %subject: marked as SPAM (%status_log).', array('%subject' => $trackback->subject, '%status_log' => $trackback->status_log));
    return;
  }

  if (empty($trackback->status)) {
    $trackback->status = variable_get('trackback_moderation', TRUE) == FALSE ? TRACKBACK_STATUS_PUBLISHED : TRACKBACK_STATUS_UNPUBLISHED;
  }  

  if (trackback_save($trackback)) {    
    trackback_invoke_trackback('insert', $trackback);
    watchdog('trackback', 'Added trackback %subject.', array('%subject' => $trackback->subject), WATCHDOG_NOTICE);//, _trackback_path($trackback, t('view')));
  }
  else {
    watchdog('trackback', 'Error adding %subject from %site(@status_log).', array('%subject' => $trackback->subject, '%site' => $trackback->site, '@status_log' => $trackback->status_log), WATCHDOG_WARNING);
  }
}

/**
 * Returns the trackback URL for given node
 */
function trackback_get_url(&$node) {
  $nid = $node->nid;
  
  if (!empty($node->tnid) && variable_get('trackback_merge_within_translations', TRUE)) {
    // Track only the original Node
    $nid = $node->tnid;
  }
  return url('trackback/'. $nid, array('absolute' => TRUE));
}

/**
 * Construct RDF metadata for Trackback url
 */
function trackback_get_RDF(&$node) {
  $url = url('node/'. $node->nid, array('absolute' => TRUE));
  $result  = "\n<!--\n";
  $result .= '<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:trackback="http://madskills.com/public/xml/rss/module/trackback/">'."\n";
  $result .= '<rdf:Description rdf:about="'. $url .'"'
              .' dc:identifier="'. $url .'"'
              .' dc:title="'. strtr(check_plain($node->title), array('--' => '&mdash;')) .'"'
              .' trackback:ping="'. trackback_get_url($node) .'" />'."\n";
  $result .= '</rdf:RDF>';
  $result .= "\n-->\n";
  
  return $result;
}

/**
 * Returns an empry Trackback Object 
 */
function trackback_get_object_trackback() {
  $trackback = array(
    'trid' => NULL,
    'nid' => NULL,
    'created' => time(),
    'site' => ip_address(),
    'name' => NULL, // The sender site name of this trackback.
    'subject' => NULL,
    'url' => NULL,
    'excerpt' => NULL,
    'status' => NULL,
    'status_log' => NULL,
  );
  return (object)$trackback;
}

/**
 *
 */
function trackback_sent($nid, $url, $success, $protocol) {
  $sql = 'INSERT INTO {trackback_sent} (nid, url, successful) VALUES (%d, "%s", %d)';
  db_query($sql, $nid, $url, $success);
  return TRUE;
}


/**
 * Check if the given trackback exists in the database
 */
function trackback_exists($trid) {
  $params = null;
  if (is_numeric($trid)) {
    $sql = "SELECT trid FROM {trackback_received} WHERE trid = %d";
    $params = $trid;
  }elseif (is_array($trid)) {
    $sql = "SELECT trid FROM {trackback_received} WHERE nid = %d AND url = '%s'";
    $params = array($trid['nid'], $trid['url']);
  }
  $result = db_query($sql, $params);
  return db_result($result);
}

/**
 * Delete given TrackbackID from database
 */
function _trackback_do_delete(&$trackback) {
  drupal_set_message(__function__);
  db_query('DELETE FROM {trackback_received} WHERE trid=%d', $trid);
  watchdog('trackback', 'Deleted trackback %subject. The trackback was posted to !link.', array('%subject' => $trackback->subject, '!link' => l(url('node/'. $trackback->nid, array('absolute' => TRUE)), 'node/'. $trackback->nid)));

  $trackback->trid = NULL;
  return TRUE;
}

/**
 * Update the given Trackback to database
 * @param <type> $trackback
 */
function _trackback_do_update(&$trackback) {
  //drupal_set_message(__function__ .'('.var_export($trackback, TRUE).')');
  
  if (trackback_exists($trackback->trid)) {
    $sql = "UPDATE {trackback_received} SET subject = '%s', excerpt = '%s', status = %d WHERE trid = %d";
    $result = db_query($sql,
        $trackback->subject,
        $trackback->excerpt,
        $trackback->status,
        $trackback->trid);
    return $result;
  }
  return FALSE;
}


/**
 * Load gived TrackbackID from database
 */
function trackback_load($trid) {
  return db_fetch_object(db_query('SELECT * FROM {trackback_received} WHERE trid=%d', $trid));
}

/**
 * Saves the given Trackback object into DB, trackback->trid is updated
 * @return TRUE on success, FALSE otherwise
 */
function trackback_save(&$trackback) {
  drupal_set_message(__function__);
  if (!is_object($trackback))
    return FALSE;
    $trid = trackback_exists(array('trid' => $trackback->nid, 'url' => $trackback->url));
  if ($trid) {
    $trackback->trid = $trid;
    $trackback->status_log = t('Trackback already exists');
    return FALSE;
  }
  else {
    $sql = "INSERT INTO {trackback_received} (nid, created, site, name, subject, url, excerpt, status) VALUES (%d, %d, '%s', '%s', '%s', '%s', '%s', %d)";
    $result = db_query($sql, $trackback->nid,
                   $trackback->created,
                   drupal_substr($trackback->site, 0, 16), // IP is xxx.xxx.xxx.xxx 16 char long
                   $trackback->name,
                   drupal_substr($trackback->subject, 0 , 64),
                   drupal_substr($trackback->url, 0, 255),
                   drupal_substr($trackback->excerpt, 0, 255), // Max 255 chars (used in .install and tracback_edit form)
                   $trackback->status
    );
    if ($result) {
      $trackback->trid = db_last_insert_id('trackback_received', 'trid');
      return TRUE;
    }
  }
  return FAlSE;
}

/**
 * Implementation of hook_block()
 */
function trackback_block($op = 'list', $delta = 'trackback_recent', $edit = array()) {
  //drupal_set_message($op . ' -- '.$delta);
  if ($op == 'list') {
    // Recent trackbacks
    $blocks['trackback_recent'] = array (
      'info' => t('Recent trackbacks'),
    );
    // Per-node Trackbacks
    $blocks['trackback_block'] = array (
      'info' => t('Trackbacks'),
      'cache' => BLOCK_CACHE_PER_PAGE | BLOCK_CACHE_PER_ROLE,
    );
    return $blocks;
  }

  switch ($delta) {
    case 'trackback_recent':
      switch ($op) {
        case 'configure':
          $form['trackback_block_recent_count'] = array(
            '#type' => 'select',
            '#title' => t('Number of trackbacks to display'),
            '#default_value' => variable_get('trackback_block_recent_count', 10),
            '#options' => drupal_map_assoc(array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30)),
            '#description' => t('How many trackbacks are displayed in the Recent Trackbacks block')
          );
          return $form;
          break;

        case 'save':
          variable_set('trackback_block_recent_count', $edit['trackback_block_recent_count']);
          break;

        case 'view':
          //$result = db_query_range('SELECT * FROM {trackback_received} WHERE status=1 ORDER BY created DESC', 0, variable_get('trackback_display_number', 10));
          //$items = array();
          //while ($tb = db_fetch_object($result)) {
          //  $items[] = _trackback_path($tb, truncate_utf8($tb->subject, 128, FALSE, TRUE)) .'<br />'. t('%time ago', array('%time' => format_interval(time() - $tb->created)));
          //}
          
          $block['subject'] = t('Recent Trackbacks');
          $block['content'] = __file__ . '::TO IMPLEMENT';//theme('item_list', $items);
          return $block;
          break;
      }
      break;
    // Per-node Setting
    case 'trackback_block':
      switch ($op) {
        case 'configure':
          $form['trackback_block_display_url'] = array(
            '#type' => 'checkbox',
            '#title' => t('Display Trackback-URL in block'),
            '#default_value' => variable_get('trackback_block_display_url', TRUE),
          );
          $form['trackback_block_display_options'] = array(
            '#type' => 'checkboxes',
            '#title' => t('Display Options for trackbacks'),
            '#description' => t(''),
            '#default_value' => variable_get('trackback_block_display_options', array('excerpt')),
            '#options' => array(
              'created' => t('Received date'),
              'excerpt' => t('Excerpt text'),
              'site' => t('IP Address'),
            ),
          );      

          return $form;
          break;
          
        case 'save':
          variable_set('trackback_block_display_url', $edit['trackback_block_display_url']);
          variable_set('trackback_block_display_options', $edit['trackback_block_display_options']);
          break;
        
        case 'view':
          if (arg(0) == 'node' && is_numeric(arg(1)) && is_null(arg(2))) {
            $node = node_load(arg(1));
            $block['subject'] = t('Trackbacks');
            
            if (isset($node->trackback_can_receive) && node_access('view', $node)) {
              $block['content'] = trackback_render_received($node, TRUE);
              if (variable_get('trackback_receive_post', TRUE) && variable_get('trackback_block_display_url', TRUE)) {
                $url = trackback_get_url($node);
                $block['content'] .= theme('trackback_url', $url, $node, TRUE);
              }
            }
            return $block;
          }
          break;
      }
      break;
  }
}

/**
 * Delete all Trackbacks for the givend NodeID
 * @param $nid
 */
function trackback_delete_trackbacks($nid) {
  db_query("DELETE FROM {trackback_node} WHERE nid = %d", $nid);
  db_query("DELETE FROM {trackback_sent} WHERE nid = %d", $nid);
  db_query("DELETE FROM {trackback_received} WHERE nid = %d", $nid);
  drupal_set_message(t('All trackbacks deleted.'));
}

/**
 * Returns an array of sented trackbacks for given Node,
 */
function trackback_get_sent(&$node, $status = 'all') {
  // drupal_set_message(__function__ . '() => '. $status);
  $nid = $node->nid;
  $return = array();
  $params = array($node->nid);
  
  $sql = 'SELECT url FROM {trackback_sent} WHERE nid = %d';
  
  switch ($status) {    
    case 'successful':
      $sql .= ' AND successful = %b';
      $params[] = 1;
      break;
    
    case 'error':
      $sql .= ' AND successful = %b';
      $params[] = 0;    
      break;
      
    default:
      // Returns ALL sent trackbscks
      break;
  } // End status switch
  $result = db_query($sql, $params);
  
  while ($send = db_fetch_object($result)) {
    $return[] = $send->url;
  }
  
  return $return;
}


/**
 * Return an array of Trackbacks object received by the given Node
 */
function trackback_get_received($node) {
  $nid = $node->nid;
  if (!empty($node->tnid) && variable_get('trackback_merge_within_translations', TRUE)) {
    $nid = $node->tnid;
  }
  $return = array();
  $result = db_query('SELECT * FROM {trackback_received} WHERE nid = %d AND status = %d ORDER BY created DESC', $nid, TRACKBACK_STATUS_PUBLISHED);
  while ($trackback = db_fetch_object($result)) {
    $return[] = $trackback;
  }
  return $return;
}


/**
 * Delete all trackback for given node-type
 * @TODO: Implement this function!
 */
function trackback_delete_trackbacks_nodetype($nodetype) {
  return;
}


/**
 * Load received trackback with given TrackbackID
 */
function trackback_load_received($trid) {
  return db_fetch_object(db_query('SELECT * FROM {trackback_received} WHERE trid=%d', $trid));
}