server-v2/app/service/business/lessonStudent.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 LessonStudentService extends CrudService {
  constructor(ctx) {
    super(ctx, 'lessonstudent');
    this.model = this.ctx.model.Business.LessonStudent;
    this.rscModel = this.ctx.model.Relation.RelationStudentCoach;
    this.lessonCoachModel = this.ctx.model.Business.LessonCoach;
    this.lessonModel = this.ctx.model.Business.Lesson;
  }

  async beforeCreate(body) {
    const { lesson_id, school_id, student_id } = body;
    // 检查是否已经有数据
    const data = await this.model.findOne({ lesson_id, school_id, student_id });
    // 数据已存在
    if (data) throw new BusinessError(ErrorCode.DATA_EXISTED, '您已报名');
    // 数据不存在
    const { is_try } = body;
    // 检查是否使用试听名额
    if (is_try === '1') {
      const num = await this.model.count({ student_id, is_try: '1' });
      if (num > 0) throw new BusinessError(ErrorCode.SERVICE_FAULT, '您已使用过免费试听的机会');
    }
    return body;
  }

  // 计算价格
  async toComputed({ lesson_id, student_id }) {
    // 通过课程id找到该课的所有教练
    const lesson = await this.lessonModel.findById(lesson_id);
    if (!lesson) throw new BusinessError(ErrorCode.DATA_NOT_EXIST, '未找到数据');
    const data = JSON.parse(JSON.stringify(lesson));
    const lessonMoney = _.get(data, 'money');
    const lessonType = _.get(data, 'type');
    if (!lessonMoney) throw new BusinessError(ErrorCode.DATA_INVALID, '课程设置错误,缺少教练费');
    // lesson中的money: 是学生应缴费用;
    // lessonStudent中的money:是学生应缴费用(公开课不计算,私教课需要查下有没有教师的优惠);
    // lessonCoach中的money: 是教师公开课每人应收的费用
    // 学生应缴计算方式: 公开课:lesson中的money; 私教课 lesson中的money - 和该教练的优惠 (可以没有)
    // 教练应收计算方式: 公开课: lessonCoach中设置的单价*人数; 私教课: (lesson的money - 对该学生的优惠) 之和
    if (lessonType === '0') {
      // 公开课
      data.real_money = lessonMoney;
    } else {
      // 找教练和学生的设置
      // 虽然用find,但实际上只有一个教练,但凡有2个,就应该不是私教课了
      const lessonCoachs = await this.lessonCoachModel.find({ lesson_id });
      if (lessonCoachs.length <= 0) return data;
      const coach_ids = lessonCoachs.map(i => i.coach_id);
      const rsc = await this.rscModel.findOne({ coach_id: coach_ids, student_id });
      if (rsc) {
        const discountType = _.get(rsc, 'config.discount_type'); // fixed;subtract;discount
        const number = _.get(rsc, 'config.number');
        if (discountType && number) {
          // 优惠目前设置3种: 固定金额; ${num}(num>1):减num元; x折; 打x折(money * (x/100))
          if (discountType === 'fixed') {
            // 固定金额
            data.real_money = number >= 0 ? number : 0;
          } else if (discountType === 'subtract') {
            data.real_money = lessonMoney - number >= 0 ? lessonMoney - number : 0;
          } else if (discountType === 'discount') {
            data.real_money = _.round(_.multiply(lessonMoney, _.divide(number, 10)), 2);
          }
          data.config = _.get(rsc, 'config');
        }
      }
    }

    return data;
  }
}

module.exports = LessonStudentService;