#!/usr/bin/php

<?php

/**
 * Root directory of Drupal installation.
 */

$_SERVER['REMOTE_ADDR'] = '127.0.0.1';
define('DRUPAL_ROOT', getcwd());
require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);

foreach (array_keys(field_read_fields(array('type' => 'field_collection'))) as $field_name) {
  // Find field collection items with duplicate revision ids
  $query = db_select("field_revision_{$field_name}", 't')
    ->fields('t', array("{$field_name}_revision_id"))
    ->groupBy("t.{$field_name}_revision_id");
  $query->addExpression("COUNT(t.{$field_name}_revision_id)", 'vidcount');
  $query->havingCondition('vidcount', 2, ">=");
  $vids = $query->execute()->fetchCol();

  // Get the fields in this field collection
  $inner_fields = field_read_instances(array('entity_type' => 'field_collection_item', 'bundle' => $field_name));

  // Each revision ID that occurs more than once
  foreach ($vids as $field_collection_revision_id) {
    // Get the values to copy
    $values = array();
    foreach ($inner_fields as $copy_from) {
      $values[$copy_from['field_name']] = db_query("SELECT * FROM field_data_{$copy_from['field_name']} WHERE revision_id = $field_collection_revision_id")->fetchAll();
    }

    // Find every instance of this revision ID
    $copies = db_select("field_revision_{$field_name}", 't')
      ->fields('t')
      ->condition("{$field_name}_revision_id", "$field_collection_revision_id")
      ->execute()
      ->fetchAllAssoc("revision_id");

    $first_copy = reset($copies);
    $field_collection_item_id = $first_copy->{"{$field_name}_value"};

    // Find new revisions of this field collection item that were made after
    // revisions were enabled in update_7003
    $new_revisions = db_select("field_revision_{$field_name}", 't')
      ->fields('t')
      ->condition("{$field_name}_revision_id", "$field_collection_revision_id", "<>")
      ->condition("{$field_name}_value", $field_collection_item_id)
      ->execute()
      ->fetchAllAssoc("revision_id");

    // Intentionally skip the first instance as it doesn't need to be modified
    while (FALSE !== ($row_to_replace = next($copies))) {
      var_dump($row_to_replace);
      exit();
    }

    //exit();
  }
}