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

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

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

  if (event.msg_id) {
    const questions = await db.collection('question')
      .aggregate()
      .match({
        msg_id: event.msg_id,
        answer: _.neq('')
      })
      .sort({
        rank: 1
      })
      .skip(event.page_token)
      .limit(event.page_size)
      .end()

    return {
      list: questions.list,
      next_page_token: event.page_token + questions.list.length,
      status: 'OK'
    }
  } else if (event.pub_id) {
    const questions = await db.collection('question')
      .aggregate()
      .lookup({
        from: 'message',
        localField: 'msg_id',
        foreignField: '_id',
        as: 'message'
      })
      .unwind('$message')
      .lookup({
        from: 'publisher',
        localField: 'message.pub_id',
        foreignField: '_id',
        as: 'message.publisher'
      })
      .unwind('$message.publisher')
      .match({
        'message.publisher._id': event.pub_id
      })
      .sort({
        question_time: -1
      })
      .skip(event.page_token)
      .limit(event.page_size)
      .end()

    return {
      list: questions.list,
      next_page_token: event.page_token + questions.list.length,
      status: 'OK'
    }
  } else {
    const questions = await db.collection('question')
      .aggregate()
      .match({
        user_id: OPENID
      })
      .sort({
        question_time: -1
      })
      .skip(event.page_token)
      .limit(event.page_size)
      .lookup({
        from: 'message',
        localField: 'msg_id',
        foreignField: '_id',
        as: 'message'
      })
      .unwind('$message')
      .end()

    return {
      list: questions.list,
      next_page_token: event.page_token + questions.list.length,
      status: 'OK'
    }
  }
}