server/app/service/util/trade.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 TradeService extends CrudService {
  constructor(ctx) {
    super(ctx, 'trade');
    this.shopModel = this.ctx.model.Shop.Shop;
    this.goodsModel = this.ctx.model.Shop.Goods;
    this.goodsSpecModel = this.ctx.model.Shop.GoodsSpec;
  }
  /**
   * 检测是否可以购买该物品
   * @param {Object} param 查询条件
   * @param param.shop_id 商店id
   * @param param.goods_id 商品id
   * @param param.goodsSpec_id 商品规格id
   * @param param.num 购买数量
   */
  async checkCanBuy({ shop_id, goods_id, goodsSpec_id, num }) {
    assert(shop_id, '缺少店铺信息');
    assert(goods_id, '缺少商品信息');
    assert(goodsSpec_id, '缺少商品规格信息');
    assert(num, '缺少购买数量');
    const result = { result: true };
    // 1.检查商店是否正常运行
    const shop = await this.shopModel.findById(shop_id);
    if (!shop) {
      result.msg = '未找到店铺';
      result.result = false;
      return result;
    }
    if (shop.status !== '1') {
      result.msg = '店铺不处于营业状态';
      result.result = false;
      return result;
    }
    // 2.检查商品是否可以购买
    const goods = await this.goodsModel.findById(goods_id);
    if (!goods) {
      result.msg = '未找到商品';
      result.result = false;
      return result;
    }
    if (goods.status === '0') {
      result.msg = '该商品已下架';
      result.result = false;
      return result;
    }
    // 3.检验该规格是否可以购买
    const goodsSpec = await this.goodsSpecModel.findById(goodsSpec_id);
    if (!goodsSpec) {
      result.msg = '未找到商品的指定规格';
      result.result = false;
      return result;
    }
    if (goods.status !== '0') {
      result.msg = '该规格的商品已下架';
      result.result = false;
      return result;
    }
    if (goods.num < num) {
      result.msg = '库存量不足';
      result.result = false;
      return result;
    }
    return result;
  }
}

module.exports = TradeService;