<?php
/**
 * @file
 * Allows users to bulk apply comment settings.
 */

/**
 * Implements hook_help().
 */
function bulk_apply_comment_settings_help($path, $args) {
  if ($path == 'admin/help#bulk_apply_comment_settings') {
    return t('To use this module, edit one of your content types, checking the box "Bulk Apply Comment settings" in the comment settings.');
  }
}

/**
 * Implements hook_module_implements_alter().
 */
function bulk_apply_comment_settings_module_implements_alter(&$implementations, $hook) {

  if ($hook == 'form_node_type_form_alter') {
    $group = $implementations['bulk_apply_comment_settings'];
    unset($implementations['bulk_apply_comment_settings']);
    $implementations['bulk_apply_comment_settings'] = $group;
  }

  if ($hook == 'form_alter' && isset($implementations['bulk_apply_comment_settings'])) {
    $group = $implementations['bulk_apply_comment_settings'];
    unset($implementations['bulk_apply_comment_settings']);
    $implementations['bulk_apply_comment_settings'] = $group;
  }
}

/**
 * Implements hook_form_FORM_ID_alter().
 */
function bulk_apply_comment_settings_form_node_type_form_alter(&$form, &$form_state) {
  $form['comment']['bulk_apply_settings'] = array(
    '#type' => 'checkbox',
    '#title' => t('Bulk Apply Comment settings'),
    '#description' => t('Bulk apply comment settings to all nodes of this type.'),
  );
  $form['#submit'][] = 'bulk_apply_comment_settings_form_node_type_form_submit';
}

/**
 * Creates the batch job to update the relevant nodes.
 */
function bulk_apply_comment_settings_form_node_type_form_submit($form, &$form_state) {

  if ($form_state['values']['bulk_apply_settings']) {

    $batch = array(
      'title' => t('Updating comment settings'),
      'init_message' => t('Initializing...'),
      'progress_message' => t('Updating relevant content.'),
      'error_message' => t('Updating node comment settings failed, please try again.'),
      'operations' => array(
        array('bulk_apply_comment_settings_batch_update_nodes',
          array($form_state['values']['type'], $form_state['values']['comment']),
        ),
      ),
    );

    batch_set($batch);

    drupal_set_message(t('Bulk applied comment settings to all nodes'));
  }
}

/**
 * Processes the relevant nodes.
 */
function bulk_apply_comment_settings_batch_update_nodes($type, $comment, &$context) {

  if (!isset($context['sandbox']['progress'])) {

    $context['sandbox']['progress'] = 0;
    $context['sandbox']['current_node'] = 0;

    $result = db_select('node', 'n')
    ->fields('n')
    ->condition('type', $type, '=')
    ->execute();

    $context['sandbox']['max'] = $result->rowCount();
  }

  $limit = 5;
  // With each pass through the callback, retrieve the next group of nids.
  $result = db_select('node', 'n')
    ->fields('n')
    ->condition('type', $type, '=')
    ->condition('nid', $context['sandbox']['current_node'], '>')
    ->orderBy('nid', 'ASC')
    ->range(0, $limit)
    ->execute()
    ->fetchAllAssoc('nid');

  $nodes = node_load_multiple(array_keys($result));
  foreach ($nodes as $node) {

    $node->comment = $comment;
    node_save($node);

    // Store some result for post-processing in the finished callback.
    $context['results'][] = check_plain($node->title);

    // Update our progress information.
    $context['sandbox']['progress']++;
    $context['sandbox']['current_node'] = $node->nid;
    $context['message'] = t('Now processing node %progress of %max (%node_title)',
      array(
        '%progress' => $context['sandbox']['progress'],
        '%max' => $context['sandbox']['max'],
        '%node_title' => $node->title)
      );
  }
  // Inform the batch engine that we are not finished,
  // and provide an estimation of the completion level we reached.
  if ($context['sandbox']['progress'] != $context['sandbox']['max']) {
    $context['finished'] = $context['sandbox']['progress'] / $context['sandbox']['max'];
  }
}