const cloud = require('wx-server-sdk')
cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
const db = cloud.database()
const _ = db.command

exports.main = async (event, context) => {
  const { OPENID } = cloud.getWXContext()
  const { postId, content } = event

  if (!postId || !content?.trim()) {
    return { code: -1, message: '参数错误' }
  }

  try {
    const postRes = await db.collection('posts').doc(postId).get().catch(() => null)
    if (!postRes?.data) return { code: -1, message: '帖子不存在' }

    const comment = {
      postId,
      authorId: OPENID,
      content: content.trim(),
      likeCount: 0,
      createdAt: db.serverDate(),
    }
    const res = await db.collection('comments').add({ data: comment })

    await db.collection('posts').doc(postId).update({
      data: { commentCount: _.inc(1) },
    })

    const authorRes = await db.collection('users')
      .where({ openid: OPENID })
      .field({ nickName: true, avatarUrl: true, openid: true })
      .get()

    return {
      code: 0,
      data: { _id: res._id, ...comment, author: authorRes.data[0] || null },
    }
  } catch (e) {
    return { code: -1, message: e.message }
  }
}