server/app/service/trade/cart.js

'use strict';
const { CrudService } = require('naf-framework-mongoose-free/lib/service');
const { BusinessError, ErrorCode } = require('naf-core').Error;
const _ = require('lodash');
const assert = require('assert');

//
class CartService extends CrudService {
  constructor(ctx) {
    super(ctx, 'cart');
    this.model = this.ctx.model.Trade.Cart;
    this.goodsSpecModel = this.ctx.model.Shop.GoodsSpec;
    this.platformActModel = this.ctx.model.System.PlatformAct;
    this.gjaModel = this.ctx.model.Shop.GoodsJoinAct;
  }

  /**
   * 返回购物车需要的数据格式
   ** 添加促销部分:
   ** 买赠,特价,加价购: 需要查询每个商品是否参与了这三项活动,需要给出对应数据
   ** 满减/折:不需要在购物车出现
   ** 套装:最后下单时组合,购物车中不需要额外修改
   * @param {Object} query 查询条件
   * @param query.customer 顾客id
   * @return {Array}
   */
  async selfCart({ customer }) {
    assert(customer, '缺少顾客信息');
    let data = await this.model.find({ customer });
    if (data.length > 0) {
      data = JSON.parse(JSON.stringify(data));
      data = data.map(i => ({ ...i, cart_id: i._id }));
    }
    await this.getCartGoodsAct(data);
    const actList = await this.ctx.service.trade.order.getActList(data);
    const pageData = await this.ctx.service.trade.order.getPageData(data, actList);
    return pageData;
  }
  /**
   * 实时获取购物车内的商品参与的活动
   * @param {Array} data 购物车商品
   */
  async getCartGoodsAct(data) {
    // 实时匹配活动问题
    const platformActList = await this.platformActModel.find({ is_use: '0' });
    for (const cart of data) {
      const { goodsSpec: spec } = cart;
      const actList = [];
      for (const act of platformActList) {
        const { _id: platform_act } = act;
        const gjaNum = await this.gjaModel.count({
          platform_act,
          'spec._id': spec,
          $or: [{ platform_act_type: '4', 'config.goods_type': 'basic' }, { platform_act_type: { $ne: '4' } }],
        });
        if (gjaNum > 0) actList.push(platform_act);
      }
      cart.act = actList;
    }
  }


  /**
   ** 创建购物车信息,若找到该店的该商品规格.进行库存校验
   ** 数量进行合并;
   ** 反之创建
   ** 添加促销活动部分:
   ** 买赠,特价,加价购: 不需要在创建时处理,而是在查询时实时处理,显示相关信息
   ** 满减/折:不需要在购物车出现
   ** 套装:只有套装需要记录在购物车中,以同一商品形式出现
   * @param {Object} body 请求参数
   * @param body.num 数量
   */
  async create({ num, ...body }) {
    const { customer, shop, goods, goodsSpec } = body;
    assert(customer, '缺少顾客信息');
    assert(shop, '缺少店铺信息');
    assert(goods, '缺少商品信息');
    assert(goodsSpec, '缺少商品规格信息');
    const query = _.pick(body, [ 'customer', 'shop', 'goods', 'goodsSpec' ]);
    const data = await this.model.findOne(query);
    if (data) {
      const buyNum = this.ctx.plus(data.num, num);
      const { enough } = await this.checkGoodsNum({ goodsSpecId: goodsSpec, num: buyNum });
      if (!enough) throw new BusinessError(ErrorCode.SERVICE_FAULT, '库存不足,无法添加至购物车');
      data.num = buyNum;
      await data.save();
    } else {
      const { enough } = await this.checkGoodsNum({ goodsSpecId: goodsSpec, num });
      if (!enough) throw new BusinessError(ErrorCode.SERVICE_FAULT, '库存不足,无法添加至购物车');
      await this.model.create({ num, ...body });
    }
  }

  /**
   * 检查商品规格的库存
   * @param {String} goodsSpecId 商品规格id
   * @param {String} cartId 购物车id
   * @param {Number} num 需要的库存数量
   * @param {Boolean} update 修改购物车
   * @return {Boolean} true:库存满足购物车条件;false:库存不满足条件
   */
  async checkGoodsNum({ cartId, goodsSpecId, num }, update = true) {
    const { populate } = this.ctx.service.shop.goodsSpec.getRefMods();
    const goodsSpec = await this.goodsSpecModel.findById(goodsSpecId).populate(populate);
    if (!goodsSpec) throw new BusinessError(ErrorCode.DATA_NOT_EXIST, '未找到商品的规格数据');
    const goods = _.get(goodsSpec, 'goods');
    const shop = _.get(goods, 'shop');
    const shopRes = this.ctx.service.util.trade.checkShop(shop);
    if (shopRes.result !== true) throw new BusinessError(ErrorCode.DATA_INVALID, shopRes.msg);
    const goodsRes = this.ctx.service.util.trade.checkGoods(goods);
    if (goodsRes.result !== true) throw new BusinessError(ErrorCode.DATA_INVALID, goodsRes.msg);
    const gsRes = this.ctx.service.util.trade.checkGoodsSpec(goodsSpec, num);
    const { num: gsnum = 0 } = goodsSpec;
    if (gsRes.result !== true) {
      return { enough: false, total: gsnum, msg: gsRes.msg };
    }
    if (update && cartId) {
      await this.model.updateOne({ _id: cartId }, { num });
    }
    return { enough: true, total: gsnum };
  }
}

module.exports = CartService;