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

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

  if (!toUserId) return { code: -1, message: '缺少目标用户' }
  if (toUserId === OPENID) return { code: -1, message: '不能给自己打招呼' }

  try {
    // 防刷：5分钟内同一对用户只能打一次招呼
    const cooldownMs = 5 * 60 * 1000
    const recent = await db.collection('messages')
      .where({
        fromId: OPENID,
        toId: toUserId,
        type: 'greeting',
        createdAt: db.command.gt(new Date(Date.now() - cooldownMs).toISOString()),
      })
      .count()

    if (recent.total > 0) {
      return { code: -1, message: '打招呼太频繁了，稍后再试' }
    }

    // 获取发送者信息
    const senderRes = await db.collection('users')
      .where({ openid: OPENID })
      .field({ nickName: true, pets: true })
      .get()
    const sender = senderRes.data[0]
    const pet = sender?.pets?.find(p => p._id === petId) || sender?.pets?.[0]

    const greeting = `${sender?.nickName || '小伙伴'} 想认识你的宠物！${pet ? `TA 的 ${pet.name} 向你打了个招呼 🐾` : '来聊聊吧 🐾'}`

    await db.collection('messages').add({
      data: {
        fromId: OPENID,
        toId: toUserId,
        content: greeting,
        type: 'greeting',
        isRead: false,
        createdAt: db.serverDate(),
      },
    })

    return { code: 0, data: null }
  } catch (e) {
    return { code: -1, message: e.message }
  }
}