Get main parent categories for a product

Question

Can someone please help me, I'm looking for a way to find the main parent product category of a WooCommerce product? Say, the product is marked under Gadgets, but the main parent of them all is Electronics.

I want this per post, as I want to add a class to each post signifying its main parent product_cat.

Please remember, product categories are custom taxonomy, and cannot be retrieved using get_category_parents(). They are listed as terms.

Thanks in advance.

// edit:

This is the code I have already, I'm calling this on each post and my posts are rendered similar to an archive page.

function all_cat_classes($post) {
    $cats = "";

    $terms = get_the_terms($post->ID, "product_cat");

    $count = 0;
    $count = count($terms);
    $key = 0;
    foreach ($terms as $cat) {

        $key++;
    }

    return $cats;
}

Answer 1

You can try this:

<?php
  $term = get_term_by( 'slug', get_query_var( 'term' ), get_query_var( 'taxonomy' ) );
  $parents = get_the_terms($term->parent, get_query_var('taxonomy') );

  foreach( $parents as $parent ) {
    echo $parent->name;
  }

?>

Answer 2

I wrote my own function to go all the way up the "chain". My recursive might not be the best implementation you've seen, but it works.

function get_parent_terms($term) {
    if ($term->parent > 0) {
        $term = get_term_by("id", $term->parent, "product_cat");
        if ($term->parent > 0) {
            get_parent_terms($term);
        } else return $term;
    }
    else return $term;
}

# Will return all categories of a product, including parent categories
function all_cat_classes($post) {
    $cats = ""; 
    $terms = get_the_terms($post->ID, "product_cat");
    $key = 0;

    // foreach product_cat get main top product_cat
    foreach ($terms as $cat) {
        $cat = get_parent_terms($cat);
        $cats .= (strpos($cats, $cat->slug) === false ? $cat->slug." " : "");
        $key++;
    }

    return $cats;
}