screen/application/common/service/RefundService.php

<?php
namespace app\common\service;

use app\common\model\OrderInfo;

class RefundService extends BaseService {
    /** @var OrderInfo */
    protected $orderInfo;
    /** @var $num int */
    protected $num;
    /** @var $num_install int */
    protected $num_install;
    public static function setOrderInfo(OrderInfo $orderInfo){
        $ins=new static;
        $ins->orderInfo=$orderInfo;
        return $ins;
    }

    /**
     * @param int $num
     */
    public function setNum(int $num)
    {
        $this->num = $num;
        return $this;
    }

    /**
     * @param int $num_install
     */
    public function setNumInstall(int $num_install)
    {
        $this->num_install = $num_install;
        return $this;
    }

    public function amount(){
        $amount=0;
        if($this->num>0){
            $amount=bcdiv($this->getOrderInfo('amount_goods_real'),$this->num);
        }
        $amount_install=0;
        if($this->num>0){
            $amount_install=bcdiv($this->getOrderInfo('amount_install'),$this->num_install);
        }
        return [$amount,$amount_install];
    }

    /**
     * @return OrderInfo
     */
    public function getOrderInfo($field=null)
    {
        return is_null($field)?$this->orderInfo:$this->orderInfo[$field];
    }
}