<?php

use Drupal\Core\Config\FileStorage;

$ct = config_typed();
foreach (Drupal::service('config.storage')->listAll() as $name) {
  if ($ct->hasConfigSchema($name)) {
    $parts = explode('.', $name);
    $module = $parts[0];
    $storage = new FileStorage("core/modules/$module/config");
    if ($base = $storage->read($name)) {
      $keys[$name] = array();
      _assemble($base, $keys[$name], config($name)->get(), $ct->get($name));
      $storage->write($name, $base);
    }
  }
  else {
    #echo "No schema for file $name\n";
  }
}
#print_r($keys);

function _assemble(&$base, &$keys, $array, $schema, $prefix = '') {
  $mapping = $schema instanceof Drupal\Core\Config\Schema\Mapping;
  $sequence = $schema instanceof Drupal\Core\Config\Schema\Sequence;
  foreach ($array as $k => $v) {
    $new_schema = FALSE;
    if ($mapping) {
      try {
        $new_schema = $schema->get($k);
      }
      catch (\InvalidArgumentException $e) {
        continue;
      }
    }
    if ($sequence) {
      $new_schema = $schema[$k];
    }
    if (is_array($v)) {
      _assemble($base[$k], $keys, $v, $new_schema, "$prefix$k.");
    }
    elseif ($new_schema) {
      $class = get_class($new_schema);
      switch ($class) {
        case 'Drupal\Core\TypedData\Plugin\DataType\String':
        case 'Drupal\Core\TypedData\Plugin\DataType\Uri':
        case 'Drupal\Core\TypedData\Plugin\DataType\Email':
        case 'Drupal\Core\Config\Schema\Property':
          break;
        case 'Drupal\Core\TypedData\Plugin\DataType\Integer':
          $base[$k] = (int)$base[$k];
          break;
        case 'Drupal\Core\TypedData\Plugin\DataType\Boolean':
          $base[$k] = (bool)$base[$k];
          break;
        default:
          echo "$class\n";
      }
    }
    else {
      #echo "No schema for $name $prefix$k\n";
    }
  }
}