hemall.terabimsoft.com.cn/app/frontend/modules/order/PriceNodeTrait.php

<?php
/**
 * Created by PhpStorm.
 * User: shenyang
 * Date: 2019/1/23
 * Time: 10:03 AM
 */

namespace app\frontend\modules\order;


use app\common\exceptions\AppException;
use Illuminate\Support\Collection;

trait PriceNodeTrait
{
    /**
     * @var Collection
     */
    public $priceCache;
    /**
     * @var Collection
     */
    private $priceNodes;

    /**
     * @return Collection
     */
    public function getPriceNodes()
    {
        if (!isset($this->priceNodes)) {
            $this->priceNodes = $this->_getPriceNodes();
        }
        return $this->priceNodes;
    }

    /**
     * 获取某个节点之后的价格
     * @param $key
     * @return mixed
     * @throws AppException
     */
    public function getPriceAfter($key)
    {
        if (!isset($this->priceCache[$key])) {
            // 找到对应的节点
            $priceNode = $this->getPriceNodes()->first(function (PriceNode $priceNode) use ($key) {
                return $priceNode->getKey() == $key;
            });
            if (!$priceNode) {
                throw new AppException("不存在的价格节点{$key}");
            }
            $this->priceCache[$key] = $priceNode->getPrice();
        }
        return $this->priceCache[$key];
    }

    public function getCurrentPrice()
    {
        if(!is_array($this->priceCache)){
            return $this->getPriceNodes()->first()->getPrice();
        }
        return array_last($this->priceCache);
    }

    /**
     * 获取某个节点之前的价格
     * @param $key
     * @return mixed
     * @throws AppException
     */
    public function getPriceBefore($key)
    {
        $nodeKey = '';
        $hasKey = false;
        foreach ($this->getPriceNodes() as $priceNode) {
            if ($priceNode->getKey() == $key) {
                $hasKey = true;
                break;
            }
            $nodeKey = $priceNode->getKey();
        }
        if(!$hasKey){
            throw new \Exception("没有key为{$key}的节点");
        }
        if (empty($nodeKey)) {
            throw new \Exception("没有{$key}更先计算的节点了");
        }
        return $this->getPriceAfter($nodeKey);
    }

    public function getPriceBeforeWeight($key)
    {

        $weight = 0;
        foreach ($this->getPriceNodes() as $priceNode) {

            //todo 主要是第一个抵扣会忽悠当前节点前一个节点的金额，所以这里返回当前节点排序
            //todo 使用大于判断会忽略与当前节点同一种排序数值的金额
            $weight = $priceNode->getWeight();
            if ($priceNode->getKey() == $key) {
                break;
            }
//            $weight = $priceNode->getWeight();
        }

        $nodeKey = $this->getPriceNodes()->filter(function ($priceNode) use ($weight) {
            return $priceNode->getWeight() < $weight;
        })->last()->getKey();

        if (empty($nodeKey)) {
            throw new \Exception("没有比{$weight}权重更小节点了");
        }
        return $this->getPriceAfter($nodeKey);
    }

    /**
     * 验证某个节点是否已存在
     * @param $key
     * @return bool true 存在  false 不存在
     */
    public function verifyPriceNodes($key)
    {
        // 找到对应的节点
        $priceNode = $this->getPriceNodes()->first(function (PriceNode $priceNode) use ($key) {
            return $priceNode->getKey() == $key;
        });
        if (!$priceNode) {
           return false;
        }

        return true;
    }
}