[已解决] 优惠卷的规则验证以及多产品支持的实现方式寻求更好的思路]

<?php

//ps, 我是在群里看到你发的,所以我过来帮你解答一下！
//我只写大概方法，优惠券最简单的方式就是使用策略模式。

class Order
{
    protected $user;
    protected $car;
    protected $promotion;
    protected $_total;

    public function __construct($user, $car, $promotion)
    {
        $this->user = $user;
        $this->car = $car;
        $this->promotion = $promotion;
    }

    public function total()
    {
        if ( !$this->total)
        {
            $this->_total = array_reduce($this->car->items(), function($first, $second)
            {
                return $first->price() + $second->price();
            });
        }

        return $this->_total;
    }

    public function discount()
    {
        return $this->total() - $this->promotion->discount($this);
    }
}

interface Promotion
{
    public function discount(Order $order);
}

//会员vip折扣
class VipPromotion implements Promotion
{

    public function discount(Order $order)
    {
        if ( $order->user->isVip() )
        {
            //
        }
    }
}

//优惠券折扣
class CodePromotion implements Promotion
{
    public function discount(Order $order)
    {
        $coupon = Coupon:make($order->coupon_id);

        //balabala!!!
    }
}

感谢果大王的思路

动态添加折扣的场景

class Order
{
    protected $user;
    protected $car;
    protected $promotion = []; //最简单用数组，也可以抽象一个manger对象。
    protected $_total;

    public function __construct($user, $car, $promotion=[])
    {
        $this->user = $user;
        $this->car = $car;
        $this->promotion = $promotion;
    }

    public function total()
    {
        if ( !$this->total)
        {
            $this->_total = array_reduce($this->car->items(), function($first, $second)
            {
                return $first->price() + $second->price();
            });
        }

        return $this->_total;
    }

    public function discount()
    {
        $maps = [];

        foreach( $this->promotion as $promotion)
        {
            $maps[$promotion->ident] = $promotion->discount($this);
        }

        // maps 就是所有折扣
    }

    public function addPromotion(Promotion $promotion)
    {
        $this->promotion[] = $promotion;
    }
}

@果实王 老哥直接贴代码厉害了。
我记得我之前是写了一个抽象工厂类。有优惠券就去处理优惠券，有打折去处理打折，有满减就去处理满减，有返现就去处理返现。当时就这样子实现了。

@果实王 这样写不对吧- -...感觉有点饶...是不是我理解错了... :sweat_smile:

class PromotionDiscountSrv
{
    public $order;
    public $user;
    // protected $promotion;
    protected $promotions = [];
    protected $_total;

    public function __construct($order = [], $uid/*, $promotion*/)
    {
        $this->order = $order ?: [];
        $this->user = $this->user ?: UserSrv::get($uid, ['uid', 'username', 'is_vip']);
        // $this->promotion = $promotion;
    }

    public function total()
    {
        if ( !$this->_total)
        {
            $this->_total = array_reduce($this->discount(), function($first, $second)
            {

                if (!empty($first))
                {

                    if (!empty($second['is_dis']))
                    {
                        return bcadd($first, $second['price'], 2);
                    }
                    return $first;
                }

                if ($second['is_dis'] === true)
                {
                    return $second['price'];
                }
            });
        }

        return $this->_total;
    }

    public function discount()
    {
        $maps = [];

        foreach( $this->promotions as $promotion)
        {
            $maps[$promotion->ident] = $promotion->discount($this);
        }

        return $maps;
    }

    public function addPromotion(Promotion $promotion)
    {
        $this->promotions[] = $promotion;
    }
}

abstract class PromotionManger
{
    protected $promotions = [];
}

interface Promotion
{
    public function discount(PromotionDiscountSrv $promotion);
    public function getDiscount();
}

//会员vip折扣
class VipPromotion implements Promotion
{

    public $ident = 'vip';
    public $disPrice = 0;

    public function __construct($id)
    {
        $this->id = $id;
    }

    public function discount(PromotionDiscountSrv $promotion)
    {

        if (!empty($promotion->user['is_vip']))
        {

            $rule = [
                'type' => 1,
                'cost' => 0,
                'price' => 9.8,
            ];

            $rule['price'] = (float)$rule['price'];
            $rule['cost'] = (float)$rule['cost'];

            if (empty($rule))
            {
                return [];
            }

            if (!empty($rule['cost']))
            {
                if ($rule['type'])
                {
                    // 折扣错误
                    if ($rule['cost'] > 9.9 || $rule['cost'] < 0.1)
                    {
                        return [];
                    }
                    // 折扣时的满减要求
                    if ($promotion->order['price'] < $rule['cost'])
                    {
                        return [];
                    }
                }
                else
                {
                    // 立减时的价格要求
                    if ($promotion->order['price'] > $rule['cost'])
                    {
                        return [];
                    }
                }
            }

            // 立减
            $discount = $rule['price'];

            // 计算价格
            if ($rule['type'])
            {
                $price = bcmul($promotion->order['price'], $rule['price'] / 10, 2);
                $discount = bcsub($promotion->order['price'], $price, 2); ;
            } else
            {
                $price = bcsub($promotion->order['price'], $discount, 2);
            }

            $this->disPrice = $discount;

            return ['is_dis' => true, 'price' => $price,  'discount' => $discount];
        }
    }
    public function getDiscount()
    {
        return $this->disPrice;
    }
}

//优惠券折扣
class CouponPromotion implements Promotion
{

    public $ident = 'coupon';

    public $disPrice = 0;

    public function __construct($id)
    {
        $this->id = $id;
    }

    public function discount(PromotionDiscountSrv $promotion)
    {
        // $coupon = Coupon::make($promotion->data['coupon_id']);

        //balabala!!!
    }
    public function getDiscount()
    {
        return $this->disPrice;
    }
}

$PromotionDiscountSrv = new PromotionDiscountSrv([
    'oid' => 1,
    'price' => 99,
], 2);

$PromotionDiscountSrv->addPromotion(new VipPromotion(1));
$PromotionDiscountSrv->addPromotion(new CouponPromotion(2));

$discountList = $PromotionDiscountSrv->total();

我在贴最后一次。。。

优惠券，满减，打折，vip，都是优惠，只是类型不一样。

你说的管道，更好的使用场景是针对某个对象进行流式处理，比如创建订单，处理优惠，切换订单状态等。

这里就能看到区别，处理优惠是其中的某一步，你也可以说我这个管道就是处理优惠的！也可以，但是没有用！！

比如：我现在需要知道，到底哪个优惠活动力度最大，你通过管道是体现不出来的！这样讲能明白吗？

那下面的$maps变量里面存储的就是个个优惠的优惠价格，我直接拿出来就可以比较了！我觉得这样更灵活一些，不要过度设计！！！！！！！！！

<?php

// 优惠处理对象。
class PromotionManger
{
    protected $promotions = [];

    public function add($promotion)
    {
        $this->promotions[] = $promotion;
    }

    // 针对order进行处理。
    public function dicount(OrderInterface $order, $payload=[])
    {
        //返回所有折扣
        $maps = [];
        foreach($promotions as $promotion)
        {
            if ($dicount = $promotion->dicount($order, $payload))
            {
                $mpas[get_class($promotion)] = $discount;
            }
        }
    }
}

class OrderProcessor
{
    protected $promotionMgr;

    public function __construct()
    {
        $this->promotionMgr = new PromotionManger();
    }

    public function process(OrderInterface $order, $payload=[])
    {
        //total 是订单原价，不需要在这里处理什么东西。
        //dicount 是订单优惠后的价格。
        $this->promotionMgr->add(new VipPromion());
        $this->promotionMgr->add(new SomePromion());
        $dicounts = $this->promotionMgr->discount($order, $payload);

        // 这里就是可以处理，无非就是把折扣加起来 然后使用 order->total() - 折扣价格 = 实际支付价格！
    }
}

//打个比方
class VipPromion extends AbcPromion
{
    public function dicount($order, $paylaod)
    {
        // user 应该从订单获取. 传进来也可以。
        $user = $oder->getUser();
        //or
        $user = request()->user();
        //or
        $user = $payload['user'];

        if ( isvip($user) )
        {
            //这里是你处理vip价格的地方.
            //比如vip用户打8折
            return $order->total() * .08; //只返回折扣后的价格！！！
        }
    }
}

//所以在service中的业务代码应该是这样

public function handleOrder()
{
    $order = Order::find(1);

    $orderProcessor = new OrderProcessor();

    $ret = $orderProcessor->process($order);

    return $ret;
}

暂时根据 @果大王的代码写了一下自己实现, 效果基本达到需求, 这里再次感谢@果大王

下面放出我这边根据自己的业务逻辑的代码, 有需要的可以参考下

promotion\Order.php

<?php

namespace App\Libs\Promotion;

class Order {

    public $user;
    public $order;

    public function __construct(array $order = [], $id = null)
    {

        if (empty($order) && !empty($id)) {
            $this->order = $id ? \ActivityOrderSrv::get($id) : [];
        }

        $this->order = $order ?? $this->order;

        $this->user = $this->user ?: \UserSrv::get($this->order['uid']);

    }

    public static function get($id = null, array $order = []) {
        return new static($id, $order);
    }

    public function getUser() {
        return $this->user;

    }

    public function total() {
        return $this->order['price'];

    }
}

promotion\OrderProcessor.php

<?php

namespace App\Libs\Promotion;

class OrderProcessor
{
    protected $promotionMgr;
    protected $discount;

    public function __construct()
    {
        $this->promotionMgr = new PromotionManger();
    }

    public function process(Order $order, $payload = [])
    {
        //total 是订单原价，不需要在这里处理什么东西。
        //dicount 是订单优惠后的价格。

        foreach ($this->discount as $discount) {
            $this->promotionMgr->add($discount);
        }

        // $this->promotionMgr->add(new vip());
        // $this->promotionMgr->add(new coupon());

        $dicounts = $this->promotionMgr->discount($order, $payload);

        $totalDiscount = array_reduce($dicounts, function($first, $second) {
            return bcadd($first, $second, 2);
        });

        // 这里就是可以处理，无非就是把折扣加起来 然后使用 order->total() - 折扣价格 = 实际支付价格！
        $total = bcsub($order->total(), $totalDiscount, 2);

        pr($total);
    }

    public function addDiscount($discount) {
        $this->discount[] = $discount;
    }
}

promotion\PromotionManger.php

<?php

namespace App\Libs\Promotion;

class PromotionManger
{
    protected $promotions = [];

    public function add($promotion)
    {
        $this->promotions[] = $promotion;
    }

    // 针对order进行处理。
    public function discount(Order $order, $payload = [])
    {
        // 返回所有折扣
        $maps = [];
        foreach($this->promotions as $promotion)
        {
            if ($discount = $promotion->discount($order, $payload))
            {
                $mpas[get_class($promotion)] = $discount;
            }
        }

        return $mpas;
    }
}

promotion\Discount.php

<?php

namespace App\Libs\Promotion;

interface Discount {
    public function discount(Order $order, $paylaod);
}

promotion\Discount\Coupon.php

<?php

namespace App\Libs\Promotion\Discount;

use App\Libs\Promotion\Discount;

class Coupon implements Discount
{
    public function discount($order, $paylaod)
    {
        // user 应该从订单获取. 传进来也可以。
        $user = $order->getUser();

        //这里是你处理vip价格的地方.
        //比如vip用户打8折

        $price = bcmul($order->total(), 9.8 / 10, 2);
        $discount = bcsub($order->total(), $price);

        return $discount;
    }
}

promotion\Discount\Vip.php

<?php

namespace App\Libs\Promotion\Discount;

use App\Libs\Promotion\Discount;

class Vip implements Discount
{
    public function discount($order, $paylaod)
    {
        // user 应该从订单获取. 传进来也可以。
        $user = $order->getUser();

        if ($user['is_vip'])
        {
            //这里是你处理vip价格的地方.
            //比如vip用户打8折

            $price = bcmul($order->total(), 9.8 / 10, 2);

            $discount = bcsub($order->total(), $price);

            return $discount; //只返回折扣后的价格！！！
        }
    }
}

获取优惠

use App\Libs\Promotion\Order;
use App\Libs\Promotion\OrderProcessor;

use App\Libs\Promotion\Discount\Vip;
use App\Libs\Promotion\Discount\Coupon;

$order = Order::get(3186);

$orderProcessor = new OrderProcessor();

// 这里根据业务逻辑动态增加相应的优惠
$orderProcessor->addDiscount(new Vip());
$orderProcessor->addDiscount(new Coupon());

$ret = $orderProcessor->process($order);
pr($ret);

暂时这样, 还没有把自己的业务逻辑加进来, 后面实现功能应该差不多也在这个基础上改动了

根据@果大王的代码, 实现的效果, 美观, 通用,完美达到预期的功能效果

@Ali ,是的优惠规则在promotion\Discount下面的类处理,只是这里没有加入业务逻辑
如果传递$paylaod['rule']也是后端取的比如套餐内的年卡优惠, 后端前置获取, 或者传递一个优惠规则的数据id在这里取rule