Show weight interval in cart

wpmudev-mp-weight-intrval.php

<?php
/*
Plugin Name: WPMU MP - Show weight interval
Plugin URI: http://premium.wpmudev.org/
Description: Show weight interval in cart
Version: 1.0.0
Author: Panos Lyrakis (WPMUDEV)
Author URI: http://premium.wpmudev.org
License: GNU General Public License (Version 2 - GPLv2)
*/

if( ! class_exists( 'WPMUDEV_MP_Weight_Interval' ) ){

    class WPMUDEV_MP_Weight_Interval{

        private static $_instance = null;
		public static function get_instance() {
        if ( is_null( self::$_instance ) ) {
            self::$_instance = new WPMUDEV_MP_Weight_Interval();
        }
        return self::$_instance;
        }

        private function __construct() {
        	add_filter( 'mp_cart/cart_meta/shipping_total', array( $this, 'display_weight_interval_in_cart' ), 10 ,2 );
        }

         /**
        * Display shipping interval after shipping row in cart
        *
        * @since 1.0.0
        * @access public
        * @return string
        */
        public function display_weight_interval_in_cart( $shipping_line, $MP_Cart ){

            $rates = $this->get_rates();
            $weight = $MP_Cart->shipping_weight();
            
            $settings = get_option( 'mp_settings' );
            $metric_system = $settings['shipping']['system'] == 'english' ? 'lb' : 'kg';  //mp_get_setting( 'shipping[system]' );
            $metric_system = apply_filters( 'wpmudev/mp/weight-interval/metric_system',$metric_system, $settings['shipping']['system'] );

            $rate = array();
            foreach ( $rates as $rate ) {
                if ( $weight <= mp_arr_get_value( 'minweight', $rate, 0 ) ) {
                    break;
                }
            }

            $inerval = number_format( (float)$rate['minweight' ] - (float)$weight, 2 );

            if( $interval >= 0 ){
                $interval_line .= '<div class="mp_cart_resume_item mp_cart_resume_item-wieght-interval">
                                    <span class="mp_cart_resume_item_label">' . __( 'Weight interval', 'mp' ) . '</span> 
                                    <span class="mp_cart_resume_item_amount">' . $inerval . ' ' . $metric_system . '</span>
                                </div>';
                $interval_line = apply_filters( 'wpmudev/mp/weight-interval/interval',$interval_line, $interval, $metric_system, $rates, $weight );
                $shipping_line .= $interval_line;
            }

            return $shipping_line;

        }

        /**
        * Get rates sorted by price from highest to lowest
        *
        * @since 1.0.0
        * @access public
        * @return array
        */
        public function get_rates() {
            $rates = (array) $this->get_setting( 'rates', array() );
            usort( $rates, array( &$this, 'sort_rates' ) );
            return $rates;
        }

        /**
		 * Gets a setting specific to the gateway
		 *
		 * @since 1.0.0
		 * @access public
		 * @param string $setting
		 * @param mixed $default
		 * @return mixed
		 */
		public function get_setting( $setting, $default = false ) {
			return mp_get_setting( "shipping->weight_rate->{$setting}", $default );
		}

    }

    add_action( 'plugins_loaded', function(){
		WPMUDEV_MP_Weight_Interval::get_instance();
	} );

}

?>