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)) {
        return;
    }

    // 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);