WooCommerce Cupons

Solved the problem with some code:

// 1. Preserve etn_ticket_data across sessions
add_filter('woocommerce_get_cart_item_from_session', function($cart_item, $values) {
    if (isset($values['etn_ticket_data'])) {
        $cart_item['etn_ticket_data'] = $values['etn_ticket_data'];
    }
    return $cart_item;
}, 10, 2);

// 2. Main coupon restriction logic with debug
add_filter('woocommerce_coupon_is_valid_for_product', function ($valid, $product, $coupon, $cart_item) {
    $log = [];

    $log[] = "---------------------------";
    $log[] = "[Coupon Filter Triggered]";
    $log[] = "Product ID: " . $product->get_id();
    $log[] = "Product Type: " . get_post_type($product->get_id());
    $log[] = "Coupon Code: " . $coupon->get_code();

    $log[] = "Cart item data:";
    $log[] = print_r($cart_item, true);

    if (strtolower($coupon->get_code()) !== 'virtual50') {
        $log[] = "Not our target coupon. Returning default: " . ($valid ? 'true' : 'false');
        error_log(implode("\n", $log));
        return $valid;
    }

    if ((int) $product->get_id() !== 377 || get_post_type($product->get_id()) !== 'etn') {
        $log[] = "Not the expected Eventin product (ID 377). Returning false.";
        error_log(implode("\n", $log));
        return false;
    }

    // ✅ FIXED: Grab the slug from etn_ticket_variations[0]
    $slug = $cart_item['etn_ticket_variations'][0]['etn_ticket_slug'] ?? 'N/A';
    $log[] = "Ticket slug in cart item: $slug";

    $allowed_slugs = [
        'ticket-377-paper-virtual-/-virtual-paper-(zoom)-8838',
    ];

    $is_allowed = in_array($slug, $allowed_slugs, true);
    $log[] = "Allowed slugs:\n" . implode("\n", $allowed_slugs);
    $log[] = "Is allowed? " . ($is_allowed ? 'Yes' : 'No');

    error_log(implode("\n", $log));
    return $is_allowed;
}, 10, 4);