class GoodsListViewSet(mixins.ListModelMixin, mixins.RetrieveModelMixin,viewsets.GenericViewSet):
    '''
    list:
        商品列表，分页，搜索，过滤，排序
    retrieve:
        获取商品详情
    '''

    # authentication_classes = (TokenAuthentication,)
    #这里必须要定义一个默认的排序,否则会报错
    queryset = Goods.objects.all().order_by('id')
    # 分页
    pagination_class = GoodsPagination
    #序列化
    serializer_class = GoodsSerializer
    filter_backends = (DjangoFilterBackend,filters.SearchFilter,filters.OrderingFilter)

    # 设置filter的类为我们自定义的类
    #过滤
    filter_class = GoodsFilter
    #搜索
    search_fields = ('name', 'goods_brief', 'goods_desc')
    #排序
    ordering_fields = ('sold_num', 'shop_price')

    #商品点击数 + 1
    def retrieve(self, request, *args, **kwargs):
        instance = self.get_object()
        instance.click_num += 1
        instance.save()
        serializer = self.get_serializer(instance)
        return Response(serializer.data)

class UserFavViewset(viewsets.GenericViewSet, mixins.ListModelMixin, mixins.CreateModelMixin, mixins.DestroyModelMixin):
    '''
    用户收藏
    '''
    #permission是用来做权限判断的
    # IsAuthenticated：必须登录用户；IsOwnerOrReadOnly：必须是当前登录的用户
    permission_classes = (IsAuthenticated,IsOwnerOrReadOnly)
    #auth使用来做用户认证的
    authentication_classes = (JSONWebTokenAuthentication,SessionAuthentication)
    #搜索的字段
    lookup_field = 'goods_id'

    #动态选择serializer
    def get_serializer_class(self):
        if self.action == "list":
            return UserFavDetailSerializer
        elif self.action == "create":
            return UserFavSerializer
        return UserFavSerializer

    def get_queryset(self):
        #只能查看当前登录用户的收藏，不会获取所有用户的收藏
        return UserFav.objects.filter(user=self.request.user)

    # 用户收藏的商品数量+1
    def perform_create(self, serializer):
        instance = serializer.save()
        # 这里instance相当于UserFav model，通过它找到goods
        goods = instance.goods
        goods.fav_num += 1
        goods.save()

class ShoppingCartViewset(viewsets.ModelViewSet):
    """
    购物车功能
    list:
        获取购物车详情
    create：
        加入购物车
    delete：
        删除购物记录
    """
    permission_classes = (IsAuthenticated, IsOwnerOrReadOnly)
    authentication_classes = (JSONWebTokenAuthentication, SessionAuthentication)
    serializer_class = ShopCartSerializer
    #商品的id
    lookup_field = "goods_id"

    def get_serializer_class(self):
        if self.action == 'list':
            return ShopCartDetailSerializer
        else:
            return ShopCartSerializer

    #获取购物车列表
    def get_queryset(self):
        return ShoppingCart.objects.filter(user=self.request.user)

    # 库存数-1
    def perform_create(self, serializer):
        shop_cart = serializer.save()
        goods = shop_cart.goods
        goods.goods_num -= shop_cart.nums
        goods.save()

    # 库存数+1
    def perform_destroy(self, instance):
        goods = instance.goods
        goods.goods_num += instance.nums
        goods.save()
        instance.delete()

    # 更新库存,修改可能是增加页可能是减少
    def perform_update(self, serializer):
        #首先获取修改之前的库存数量
        existed_record = ShoppingCart.objects.get(id=serializer.instance.id)
        existed_nums = existed_record.nums
        # 先保存之前的数据existed_nums
        saved_record = serializer.save()
        #变化的数量
        nums = saved_record.nums-existed_nums
        goods = saved_record.goods
        goods.goods_num -= nums
        goods.save()

class AlipayView(APIView):
    def get(self, request):
        """
        处理支付宝的return_url返回
        """
        processed_dict = {}
        # 1. 获取GET中参数
        for key, value in request.GET.items():
            processed_dict[key] = value
        # 2. 取出sign
        sign = processed_dict.pop("sign", None)

        # 3. 生成ALipay对象
        alipay = AliPay(
            appid="2016091500517456",
            app_notify_url="http://47.93.198.159:8000/alipay/return/",
            app_private_key_path=private_key_path,
            alipay_public_key_path=ali_pub_key_path,  # 支付宝的公钥，验证支付宝回传消息使用，不是你自己的公钥,
            debug=True,  # 默认False,
            return_url="http://47.93.198.159:8000/alipay/return/"
        )

        verify_re = alipay.verify(processed_dict, sign)

        # 这里可以不做操作。因为不管发不发return url。notify url都会修改订单状态。
        if verify_re is True:
            order_sn = processed_dict.get('out_trade_no', None)
            trade_no = processed_dict.get('trade_no', None)
            trade_status = processed_dict.get('trade_status', None)

            existed_orders = OrderInfo.objects.filter(order_sn=order_sn)
            for existed_order in existed_orders:
                existed_order.pay_status = trade_status
                existed_order.trade_no = trade_no
                existed_order.pay_time = datetime.now()
                existed_order.save()

            response = redirect("/index/#/app/home/member/order")
            return response

        else:
            response = redirect("index")
            return response

    def post(self, request):
        """
        处理支付宝的notify_url
        """
        #存放post里面所有的数据
        processed_dict = {}
        #取出post里面的数据
        for key, value in request.POST.items():
            processed_dict[key] = value
        #把signpop掉，文档有说明
        sign = processed_dict.pop("sign", None)

        #生成一个Alipay对象
        alipay = AliPay(
            appid="2016091500517456",
            app_notify_url="http://47.93.198.159:8000/alipay/return/",
            app_private_key_path=private_key_path,
            alipay_public_key_path=ali_pub_key_path,  # 支付宝的公钥，验证支付宝回传消息使用，不是你自己的公钥,
            debug=True,  # 默认False,
            return_url="http://47.93.198.159:8000/alipay/return/"
        )

        #进行验证
        verify_re = alipay.verify(processed_dict, sign)

        # 如果验签成功
        if verify_re is True:
            #商户网站唯一订单号
            order_sn = processed_dict.get('out_trade_no', None)
            #支付宝系统交易流水号
            trade_no = processed_dict.get('trade_no', None)
            #交易状态
            trade_status = processed_dict.get('trade_status', None)

            # 查询数据库中订单记录
            existed_orders = OrderInfo.objects.filter(order_sn=order_sn)
            for existed_order in existed_orders:
                # 订单商品项
                order_goods = existed_order.goods.all()
                # 商品销量增加订单中数值
                for order_good in order_goods:
                    goods = order_good.goods
                    goods.sold_num += order_good.goods_num
                    goods.save()

                # 更新订单状态
                existed_order.pay_status = trade_status
                existed_order.trade_no = trade_no
                existed_order.pay_time = datetime.now()
                existed_order.save()
            #需要返回一个'success'给支付宝，如果不返回，支付宝会一直发送订单支付成功的消息
            return Response("success")