Set Category For Product

set_product_category_item.php

<?php
private function set_product_category_item($category, $parent_id = null)
{
   $taxonomy = 'product_cat';

   if (term_exists($category, $taxonomy)) {
      $category_id = get_term_by('name', $category, $taxonomy)->term_id;
   } else {
      //$term_data = wp_insert_term($attributes['parent2'], $taxonomy, ['parent' => $parent_id_1]);
      if(!empty($parent_id)) {
         $term_data = wp_insert_term($category, $taxonomy, ['parent' => $parent_id]);
      } else {
         $term_data = wp_insert_term($category, $taxonomy);
      }
      
      if(is_wp_error($term_data)) {
         $category_id = null;
      } else {
         $category_id = $term_data['term_id'];
      }
   }

   return $category_id;
}