WooCommerce WC Vendors Shipping Splitter divided

<?php
/*
Plugin Name: WC Vendors Package Shipping Splitter
Plugin URI: mailto:goteamscotch@gmail.com
Description: Gives vendors their externally calculated shipping dues. TEST CODE
Version: 0.1b
Author: GoTeamScotch
*/

/*
Notes
- This requires the plugin Packages Configuration for WooCommerce by Jason Judge
*/

if (!defined('ABSPATH')) die; // Don't allow direct loading
add_action( 'plugins_loaded', array( 'GTS_WCV_Ship', 'init' ), 20 );

if (!class_exists('GTS_WCV_Ship')) {
    class GTS_WCV_Ship {
        public static $instance = null;

        public static function init() {
            null === self::$instance AND self::$instance = new self;
            return self::$instance;
        }

        public function __construct() {
            include_once ABSPATH . 'wp-admin/includes/plugin.php';
            $req = array('woocommerce/woocommerce.php', 'wc-vendors/class-wc-vendors.php', 'packages-configuration-for-woocommerce/multiple-packages-shipping.php');
            foreach ($req as $plugin)
                if (!is_plugin_active($plugin)) {
                    deactivate_plugins( plugin_basename( __FILE__ ) );
                    die(__CLASS__ . ": Missing a required plugin: {$plugin}");
                }

            $give_shipping = WC_Vendors::$pv_options->get_option( 'give_shipping' );
            if ($give_shipping == false)
                add_action('admin_notices', array($this, 'wrong_settings'));

            add_action('woocommerce_add_shipping_order_item', array($this, 'add_shipping_line_vendor'), 10, 3);
            add_filter('wcvendors_shipping_due', array($this, 'get_vendors_shipping_dues_product'), 10, 3);
        }

        public function wrong_settings() {
            ?>
            <div class="updated">
                <p>Attention: You may not have WC Vendors configured correctly! Please enable the setting "Give vendors shipping" for this plugin to work properly.<br><em>Note: If you override this option on a per-vendor basis, then you may ignore this message.</em></p>
                <p class="description">Generated by WC Vendors Package Shipping Splitter</p>
            </div>
            <?php
        }

        // adds extra meta data to the shipping order items so we can tell which vendor the shipping line is destined for
        public function add_shipping_line_vendor( $order_id, $item_id, $package_key ) {
            $packages = WC()->shipping->get_packages();

            if (!isset($packages[$package_key])) return;

            $package = $packages[$package_key];

            $sample_product = array_pop($package['contents']);

            $vendor_id = WCV_Vendors::get_vendor_from_product($sample_product['product_id']);
            if (WCV_Vendors::is_vendor($vendor_id))
                wc_add_order_item_meta($item_id, '_vendor_id', $vendor_id, true);
        }

        // gets fired by WC Vendors when finding out how much shipping fees to give to the vendor for a given product
        public function get_vendors_shipping_dues_product( $shipping_dues, $order_id, $product ) {
            static $order = null;
            if (is_null($order) || ($order instanceof WC_Order && $order->ID != $order_id))
                $order = new WC_Order($order_id);

            $vendor_id = WCV_Vendors::get_vendor_from_product($product['product_id']);
            if (WCV_Vendors::is_vendor($vendor_id)) {
                $order = new WC_Order($order_id);

                $shipping_methods = $order->get_shipping_methods();
                foreach ($shipping_methods as $key => $data) {
                    if (!isset($data['vendor_id']) || (isset($data['vendor_id']) && $data['vendor_id'] != $vendor_id)) continue;

                    $vendor_owed_shipping = $data['cost']; // this is their total shipping due for the entire order
                    $number_items_pkg = count(explode('|', $data['product_ids']));
                    $shipping_dues['amount'] = (($vendor_owed_shipping / $number_items_pkg) * $product['qty']);
                    $shipping_dues['tax'] = $data['taxes'];
                    break;
                }
            }
            return $shipping_dues;
        }
    }
}