service-zr/app/service/zrOrder.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 ZrOrderService extends CrudService {
  constructor(ctx) {
    super(ctx, 'zrorder');
    this.redis = this.app.redis;
    this.redisKey = this.app.config.redisKey;
    this.redisTimeout = this.app.config.redisTimeout;
    this.model = this.ctx.model.ZrOrder;
    this.goodsModel = this.ctx.model.ZrGoods;
    this.pointModel = this.ctx.model.Base.Point;
    this.shopModel = this.ctx.model.Base.Shop;
    this.addressModel = this.ctx.model.Base.Address;
  }
  // 进入订单页前,通过函数判断,存储是否可以购买 指定商品 的 指定数量
  // 下单,走同样的函数判断.
  // 直接生成订单,扣除积分

  async toMakeOrder({ key }) {
    key = `${this.redisKey.orderKeyPrefix}${key}`;
    let data = await this.redis.get(key);
    if (!data) throw new BusinessError(ErrorCode.SERVICE_FAULT, '请求超时,请重新进入下单页');
    data = JSON.parse(data);
    const { shop, goods, num: buy_num } = data;
    // 店铺信息
    const shopInfo = await this.shopModel.findById(shop);
    // 商品信息
    const goodsInfo = await this.goodsModel.findById(goods);
    // 消耗积分
    const costTotal = this.ctx.multiply(_.get(goodsInfo, 'cost'), buy_num);
    // 积分信息
    const customer = _.get(this.ctx.user, '_id');
    const points = await this.pointComputedTotal({ customer });
    // 地址信息
    const address = await this.addressModel.findOne({ customer, is_default: '1' });
    return { buy_num, shop: shopInfo, goods: goodsInfo, points, address, costTotal };
  }

  /**
   * 检查是否可以购买商品,并生成缓存
   * @param {Object} body 参数体
   * @param body.shop 店铺id
   * @param body.goods 尊荣商品id
   * @param body.num 购买数量
   * @param {Boolean} makeCache 是否生成缓存
   */
  async checkCanBuy({ shop, goods, num }, makeCache = true) {
    const result = { result: true };
    const shopInfo = await this.shopModel.findById(shop);
    if (!shopInfo || _.get(shopInfo, '1')) {
      result.result = false;
      result.msg = '店铺当前不处于营业状态';
      return result;
    }
    const goodsInfo = await this.goodsModel.findById(goods);
    if (!goodsInfo) {
      result.result = false;
      result.msg = '未找到尊荣商品';
      return result;
    }
    const user = this.ctx.user;
    const customer = _.get(user, '_id');
    if (!customer) {
      result.result = false;
      result.msg = '未找到用户信息';
    }
    // #region 库存判断
    const knum = _.get(goodsInfo, 'num');
    const res = this.ctx.minus(knum, num);
    if (res <= 0) {
      result.result = false;
      result.msg = '库存不足';
      return result;
    }
    // #endregion

    // #region 积分判断
    const pointTotal = await this.pointComputedTotal({ customer });
    // 计算购买所需积分
    const cost = _.get(goodsInfo, 'cost', 0);
    if (cost === 0) {
      result.result = false;
      result.msg = '商品设置的尊荣有误,无法进行购买';
      return result;
    }
    const costTotal = this.ctx.multiply(cost, num);
    const afterCost = this.ctx.minus(pointTotal, costTotal);
    if (afterCost < 0) {
      result.result = false;
      result.msg = '您的积分不足';
      return result;
    }
    // #endregion

    if (makeCache) {
      const key = await this.makeOrderKey({ shop, goods, num });
      result.key = key;
    }
    return result;
  }

  // 生成key
  async makeOrderKey(data) {
    const str = this.createNonceStr();
    const key = `${this.redisKey.orderKeyPrefix}${str}`;
    const value = JSON.stringify(data);
    await this.redis.set(key, value, 'EX', this.redisTimeout);
    return str;
  }
  /**
   * 计算用户的积分
   * @param {Object} data 数据对象
   * @param data.customer 用户数据id
   */
  async pointComputedTotal({ customer }) {
    assert(customer, '缺少用户信息');
    const res = await this.pointModel.find({ customer });
    const total = res.reduce((p, n) => {
      let point = n.point;
      if (!(n.source === '0' || n.source === '1')) point = -point;
      return this.ctx.plus(p, point);
    }, 0);
    return total;
  }

  // 随机字符串产生函数
  createNonceStr() {
    return Math.random().toString(36).substr(2, 15);
  }
}

module.exports = ZrOrderService;