Untitled

const db = require('../../../models/index')

const getPostContent = (req, res) => {

  const userID = req.user_id
  const postID = req.query.post_id

  const findPostPromise = (postID) => {
    return db.post.findOne({
      attributes: {
        exclude: [
          "createdAt", "updatedAt", "deletedAt"
        ]
      },
      where: {
        id: postID,
      },
      include: [
        {
          model: db.tag,
          through: { attributes: [] },
          attributes: ["id", "category", "text"],
        },
        {
          model: db.postpicture,
          attributes: ["id", "name"],
        }
      ]
    })
      .then(postInst => {
        if (postInst === null)
          throw new Error("Cannot find any post by post_id")
        return postInst
      })
      .catch(err => {
        throw new Error("[Fail to find the post]: " + err)
      })
  }
  const updatePostClickPromise = (postInst, t) => {
    return postInst.increment('user_clicked_count', { by: 1 }, { transaction: t })
      .then(() => {
        return postInst
      })
      .catch(err => {
        throw new Error("[Fail to update post click count]: " + err)
      })
  }
  const createUserClickOnPostPromise = (userID, postID, t) => {
    return db.data_user_clicks_on_post.create({
      user_id: userID,
      post_id: postID
    }, { transaction: t })
      .catch(err => {
        throw new Error("[Fail to create user click on post]: " + err)
      }) 
  }
  const collectUserClickOnPostPromise = (postInst, userID, postID, t) => {
    return db.data_user_clicks_on_post.findOne({
      where: {
        user_id: userID,
        post_id: postID
      }
    })
      .then(postClickInst => {
        if (postClickInst !== null)
          return postClickInst.increment('click_count', { by: 1 }, { transaction: t })
        else
          return createUserClickOnPostPromise(userID, postID, t)
      })
      .then(() => {
        return postInst
      })
      .catch(err => {
        throw new Error("[Fail to update user clicks on post count]: " + err)
      })
  }
  const postPostProcessing = (postInst) => {
    postInst.postpictures.forEach(picture => {
      picture.dataValues.picture = process.env.AWS_CLOUDFRONT_URL + picture.dataValues.name
      delete picture.dataValues.name
    })
    postInst.dataValues.pictures = postInst.dataValues.postpictures
    delete postInst.dataValues.postpictures
    return postInst
  }
  const checkPostStatus = (start, end) => {
    const currentDate = new Date()
    currentDate.setHours(currentDate.getHours() - 8);
    if (start <= currentDate && currentDate <= end)
      return "進行中"
    else if (currentDate < start)
      return "即將進行"
    else
      return "已結束"
  }

  return db.sequelize.transaction((t) => {
    return findPostPromise(postID)
      .then(postInst => {
        return updatePostClickPromise(postInst, t)
      })
      .then(postInst => {
        return collectUserClickOnPostPromise(postInst, userID, postID, t)
      })
      .then(postInst => {
        return postPostProcessing(postInst)
      })
      .then(postInst => {
        postInst.dataValues.status = checkPostStatus(postInst.start_date, postInst.end_date)
        return postInst
      })
      .then(postInst => {
        return res.status(200).send(postInst)
      })
      .catch(err => {
        return res.status(400).send(err.message)
      })
  })
}

module.exports = getPostContent