met checkout redirection

add_action('init', function () {

    add_rewrite_rule('^meta-checkout/?$', 'index.php?meta_checkout=1', 'top');

});

add_filter('query_vars', function ($vars) {

    $vars[] = 'meta_checkout';

    return $vars;

});

add_action('template_redirect', function () {

    if (!get_query_var('meta_checkout')) {

        return;

    }

    if (!function_exists('WC') || !WC()->cart) {

        return;

    }

    // Clear current cart so Meta checkout starts fresh.

    WC()->cart->empty_cart();

    /*

     * Expected URL format:

     * /meta-checkout/?products=123:1,456:2&coupon=SAVE10

     *

     * products = product_id:qty,product_id:qty

     * coupon   = optional coupon code

     */

    $products = isset($_GET['products']) ? sanitize_text_field(wp_unslash($_GET['products'])) : '';

    $coupon   = isset($_GET['coupon']) ? sanitize_text_field(wp_unslash($_GET['coupon'])) : '';

    if ($products) {

        $items = explode(',', $products);

        foreach ($items as $item) {

            $parts = explode(':', $item);

            $product_id = isset($parts[0]) ? absint($parts[0]) : 0;

            $qty        = isset($parts[1]) ? max(1, absint($parts[1])) : 1;

            if ($product_id > 0) {

                WC()->cart->add_to_cart($product_id, $qty);

            }

        }

    }

    if ($coupon) {

        WC()->cart->apply_coupon($coupon);

    }

    wp_safe_redirect(wc_get_checkout_url());

    exit;

});