const cloud = require('wx-server-sdk')
cloud.init({ env: cloud.DYNAMIC_CURRENT_ENV })
const db = cloud.database()
const _ = db.command
const PAGE_SIZE = 10

exports.main = async (event, context) => {
  const { OPENID } = cloud.getWXContext()
  const { page = 0, type = 'hot', userId, latitude, longitude } = event

  try {
    let query = db.collection('posts')
    const skip = page * PAGE_SIZE

    if (userId) {
      // 某用户的帖子
      query = query.where({ authorId: userId })
    } else if (type === 'feed') {
      // 关注的用户帖子
      const followsRes = await db.collection('follows')
        .where({ followerId: OPENID })
        .field({ followeeId: true })
        .get()
      const followeeIds = followsRes.data.map(f => f.followeeId)
      followeeIds.push(OPENID)
      query = query.where({ authorId: _.in(followeeIds) })
    } else if (type === 'nearby' && latitude && longitude) {
      // 附近帖子：使用地理围栏查询（简化版，用 geo_near）
      query = query.where(
        _.and([
          { 'location.latitude': _.gt(latitude - 0.1) },
          { 'location.latitude': _.lt(latitude + 0.1) },
          { 'location.longitude': _.gt(longitude - 0.15) },
          { 'location.longitude': _.lt(longitude + 0.15) },
        ])
      )
    }
    // type === 'hot' 全量按热度排序

    const total = await query.count()
    const postsRes = await query
      .orderBy('createdAt', 'desc')
      .skip(skip)
      .limit(PAGE_SIZE)
      .get()

    const posts = postsRes.data

    // 批量获取作者信息
    const authorIds = [...new Set(posts.map(p => p.authorId))]
    const authorsRes = await db.collection('users')
      .where({ openid: _.in(authorIds) })
      .field({ nickName: true, avatarUrl: true, openid: true, pets: true, location: true })
      .get()
    const authorMap = {}
    authorsRes.data.forEach(u => { authorMap[u.openid] = u })

    // 获取当前用户点赞状态
    const postIds = posts.map(p => p._id)
    const likesRes = await db.collection('likes')
      .where({ userId: OPENID, postId: _.in(postIds) })
      .field({ postId: true })
      .get()
    const likedSet = new Set(likesRes.data.map(l => l.postId))

    const enriched = posts.map(p => ({
      ...p,
      author: authorMap[p.authorId] || null,
      isLiked: likedSet.has(p._id),
    }))

    return {
      code: 0,
      data: {
        list: enriched,
        total: total.total,
        hasMore: skip + posts.length < total.total,
      },
    }
  } catch (e) {
    return { code: -1, message: e.message }
  }
}