Automatically apply "tribe_events_cat" taxonomy terms to WooCommerce tickets when tickets are saved or updated.

the-events-calendar-automatic-ticket-categories.php

<?php

// Apply product categories to newly created or saved tickets that match the The Events Calendar categories of the associated event
add_action('event_tickets_after_save_ticket', function ($event_id, $ticket, $raw_data, $classname) {
    if (! empty($ticket) && isset($ticket->ID)) {

        // Apply the "event-tickets" category to add tickets so that all tickets have at least this category to start
        wp_add_object_terms($ticket->ID, 'event-tickets', 'product_cat');

        // Get all the other "tribe_events_cat" taxonomy terms on the event
        $terms = get_the_terms($event_id, 'tribe_events_cat');

        // Initialize our array of new terms to be inserted into the "product_cat" taxonomy
        $product_terms = [];

        // Loop through all the "tribe_events_cat" taxonomy terms on the event and create them as product_cat categories if necessary
        foreach ($terms as $term) {

            // Insert the matching term into the "product_cat" taxonomy
            wp_insert_term($term->name, 'product_cat', [
              'slug' => 'event-tickets-' . $term->slug
            ]);

            // Put the new term in our array so we can apply them all to the ticket
            $product_terms[] = 'event-tickets-' . $term->slug;
        }

        // Add all the new "product_cat" taxonomy terms to the ticket
        wp_add_object_terms($ticket->ID, $product_terms, 'product_cat');
    }
}, 10, 4);