<?php

/**
 * @file
 * Main file for the Multiping module, which allows pinging multiple sites.
 */

// HOOKS

/**
 * Implements hook_menu().
 */
function multiping_menu() {
  $items['admin/config/services/multiping'] = array(
    'title' => 'Multiping',
    'description' => 'Configure when to ping services.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('multiping_settings_form'),
    'access arguments' => array('administer multiping'),
  );
  $items['admin/config/services/multiping/settings'] = array(
    'title' => 'Settings',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => 10,
  );
  return $items;
}

/**
 * Implements hook_ctools_plugin_type().
 */
function multiping_ctools_plugin_type() {
  return array(
    'ping_methods' => array(),
  );
}

/**
 * Implements hook_permission().
 */
function multiping_permission() {
  return array(
    'administer multiping' => array(
      'title' => t('Administer ping services'),
      'description' => t('Create, edit, delete, and perform ping for ping services.'),
    ),
  );
}

/**
 * Implements hook_cron_queue_info().
 */
function multiping_cron_queue_info() {
  $queues['multiping_items'] = array(
   'worker callback' => '_multiping_ping_queue_item',
   'time' => 60,
 );
 return $queues;
}

/**
 * Implements hook_node_insert().
 */
function multiping_node_insert($node) {
  multiping_queue_node($node, 'insert');
}

/**
 * Implements hook_node_update().
 */
function multiping_node_update($node) {
  multiping_queue_node($node, 'update');
}

// API

/**
 * Fetch metadata on a specific ping_method plugin.
 *
 * @param $ping_method
 *   Name of a ping method.
 *
 * @return
 *   An array with information about the requested ping method.
 */
function multiping_get_ping_method($ping_method) {
  ctools_include('plugins');
  return ctools_get_plugins('multiping', 'ping_methods', $ping_method);
}

/**
 * Fetch metadata for all ping_method plugins.
 *
 * @return
 *   An array of arrays with information about all available ping methods.
 */
function multiping_get_ping_methods() {
  ctools_include('plugins');
  return ctools_get_plugins('multiping', 'ping_methods');
}

function multiping_queue_node($node, $reason) {
  $to_queue = array();

  foreach (module_implements('multiping_queue_node') as $module) {
    $module_queue = module_invoke($module, 'multiping_queue_node', $node, $reason);

    $to_queue = array_merge($to_queue, array_map(function ($item) use ($module, $node, $reason) {
      $item += array(
        'module' => $module,
        'node' => $node->nid,
        'reason' => $reason,
      );
      return $item;
    }, $module_queue));
  }

  drupal_alter('multiping_queue_node', $to_queue);

  // If the settings say to ping at once rather than queue, then do so!
  if (variable_get('multiping_pingatonce', TRUE)) {
    foreach ($to_queue as $item) {
      _multiping_ping_queue_item($item);
    }
  } else {
    $queue = DrupalQueue::get('multiping_items');

    foreach ($to_queue as $item) {
      $queue->createItem($item);
    }
  }
}

// Internal methods

function _multiping_ping_queue_item($item) {
  // Fetch additional data

  if (is_numeric($item['node'])) {
    $item['node'] = node_load($item['node']);
  }

  // If the triggering module has been disabled or the node removed, just chill
  if (!module_exists($item['module']) || !$item['node']) {
    return;
  }

  $target = module_invoke($item['module'], 'multiping_target', $item, $item['node']);

  if ($target) {
    $item = array_merge($item, $target);

    unset($item['node']);
    $item['target'] = url($item['target'], array('absolute' => TRUE));

    multiping_ping_item($item);
  }
}

function multiping_ping_item($item, $force = FALSE) {
  // Avoid the same ping from being repeated within the same cron run

  $fingerprint = drupal_hash_base64(implode('::', array(
    $item['method'],
    $item['endpoint'],
    $item['target'],
  )));

  $last_ping = cache_get('multiping_ping::' . $fingerprint);
  $cron_last = variable_get('cron_last');

  if (!$force && $last_ping && $last_ping->data == $cron_last) {
    // We have already performed this ping this cron round
    return;
  }

  cache_set('multiping_ping::' . $fingerprint, $cron_last);

  // Do the ping

  $method = multiping_get_ping_method($item['method']);

  if ($method) {
    $result = call_user_func($method['ping callback'], $item);
  }

  $name = empty($item['name']) ? $item['endpoint'] : $item['name'];

  if (empty($result)) {
    watchdog('multiping', 'Failed to notify %site about %target.', array(
      '%site' => $name,
      '%target' => $item['target'],
    ), WATCHDOG_ERROR);
  } else {
    //TODO: This is _very_ verbose for larger sites! Find a better way!

    watchdog('multiping', 'Successfully notified %site about %target.', array(
      '%site' => $name,
      '%target' => $item['target'],
    ), WATCHDOG_INFO);
  }

  //TODO: Create a retry mechanism!
}

function multiping_cache_clear() {
  cache_clear_all('multiping', 'cache', TRUE);
}

function multiping_path_endpoints($path = NULL, $method = null) {
  if (!$path) {
    $path = current_path();
  }

  $router_item = menu_get_item($path);

  if (!$router_item) {
    return array();
  }

  $result = array();

  foreach (module_implements('multiping_path_endpoints') as $module) {
    $result = array_merge($result, module_invoke($module, 'multiping_path_endpoints', $router_item['path'], $method));
  }

  return $result;
}

function _multiping_get_terms($nid) {
  $terms = &drupal_static(__FUNCTION__);

  if (empty($terms)) {
    $terms = array();
  }

  if (!isset($terms[$nid])) {
     $terms[$nid] = db_query('SELECT tid FROM {taxonomy_index} WHERE nid = :nid', array(
         ':nid' => $nid
       ))->fetchCol();
  }

  return $terms[$nid];
}

function _multiping_get_vocabularies($nid) {
  $data = &drupal_static(__FUNCTION__);

  if (empty($data)) {
    $data = array();
  }

  if (!isset($data[$nid])) {
    $data[$nid] = db_query(
      'SELECT DISTINCT tv.vid, tv.machine_name FROM {taxonomy_vocabulary} tv ' .
      'INNER JOIN {taxonomy_term_data} td  ON td.vid = tv.vid ' .
      'INNER JOIN {taxonomy_index} ti ON ti.tid = td.tid ' .
      'WHERE ti.nid = :nid',
      array(':nid' => $nid)
    )->fetchAll(PDO::FETCH_ASSOC);
  }

  return $data[$nid];
}

function _multiping_module_invoke_until_non_null($hook) {
  $args = func_get_args();

  foreach (module_implements($hook) as $module) {
    $result = call_user_func_array('module_invoke', array_merge(array($module), $args));

    if ($result !== NULL) {
      return $result;
    }
  }
}

function multiping_settings_form($form, &$form_state) {
  $form['multiping_pingatonce'] = array(
    '#type' => 'checkbox',
    '#title' => t('Ping after post'),
    '#default_value' => variable_get('multiping_pingatonce', TRUE),
    '#description' => t('Ping directly after post/update (instead of pinging during the cron job runs). Use this if possible to avoid the added delay a cron job can result.'),
  );
  $form['multiping_timeout'] = array(
    '#type' => 'select',
    '#title' => t('Timeout for each ping'),
    '#default_value' => variable_get('multiping-timeout', 3),
    '#options' => drupal_map_assoc(array(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)),
    '#description' => t('Time to ping each service in seconds')
  );
  return system_settings_form($form);
}