// 云函数入口文件
const cloud = require('wx-server-sdk')

cloud.init()
const db = cloud.database()

// 云函数入口函数
exports.main = async (event, context) => {
  const {
    OPENID
  } = cloud.getWXContext()

  const message = await db.collection('message')
    .aggregate()
    .match({
      _id: event.msg_id
    })
    .lookup({
      from: 'publisher',
      localField: 'pub_id',
      foreignField: '_id',
      as: 'publisher'
    })
    .unwind('$publisher')
    .end()
  if (message.list.length === 0) {
    return {
      errMsg: '信息不存在',
      status: 'ERR'
    }
  }

  await db.collection('read')
    .add({
      data: {
        user_id: OPENID,
        msg_id: event.msg_id || '',
        read_time: new Date()
      }
    })

  return {
    data: message.list[0],
    status: 'OK'
  }
}