/**
   * Parse Typo3 Categories.
   *
   * Converts Typo3 categories to Specialties
   *
   * @param [array] $categories
   *   Array of clean numeric Typo3 Category IDs.
   *
   * @return [array]
   *   Array of arrays defining what data was parsed from where for what.
   */
  public function parseTaxonomyMapping($categories) {
    // There will be other entries in this array, based on the type mapping...
    // Examples: specialty, articletype.
    $output = array(
      'unmapped' => [],
      'notfound' => [],
    );

    // This array holds all target_term column names in the
    // $this->target_topic_map mapping document.
    $target_term_columns = $this->getTargetTermsMap();

    // Move through each category UID present.
    foreach ($categories as $id) {

      // If the ID exists in our remapping list...
      if (isset($this->target_topic_map[$id])) {
        $map_row = $this->target_topic_map[$id];

        // Process all Specialty term mapping columns.
        foreach ($target_term_columns as $target_term_column) {

          // Get the machine name. This will look like "specialty-01".
          $machine_name = isset($map_row[$target_term_column]) && !empty($map_row[$target_term_column]) ? $map_row[$target_term_column] : FALSE;
          $machine_name_process = $this->processMachineName($machine_name);

          // This mapping column is empty or not set.
          if (!$machine_name) {
            $output['unmapped'][] = 'Machine Name Not Set: ' . $machine_name;
            continue;
          }

          // This column is set to be ignored. Stop processing this column.
          if ($machine_name == '[ignore]' || $machine_name == '[confirm-ignore]') {
            continue;
          }

          // Since the mapping works differently depending on the machine name
          // type, call a method specific to this machine type.
          // @See $this->getTermNameTypeSpecialties()
          // @See $this->getTermNameTypeArticletype()
          $machine_name_type = $machine_name_process['type'];
          $type_class = 'getTermNameType' . ucfirst($machine_name_type);
          if (method_exists($this, $type_class)) {
            $term_name = $this->$type_class($machine_name, $machine_name_process);
          }
          else {
            $output['unmapped'][] = "Type processing method doesn't exist: {$type_class}";
            continue;
          }

          // At this point we need to confirm that we can get to the term name.
          if (!$term_name) {
            $output['unmapped'][] = 'Taxonomy Not Defined (' . $machine_name_type . '): ' . $machine_name;
            continue;
          }

          // Add the taxonomy tern name to the correct array.
          if (!isset($output[$machine_name_type])) {
            $output[$machine_name_type] = array();
          }

          $output[$machine_name_type][] = $term_name;
        }

      }
      else {
        $output['notfound'][] = $id;
      }
    }

    // Ensure no duplicate data for output without key/value storage.
    foreach ($output as $output_key => $output_value) {
      $output[$output_key] = array_unique($output[$output_key]);
    }

    return $output;
  }