// 云函数 login — 登录 + 首次建用户，返回 hasDog 决定跳建档/首页
// 契约见 docs/03-云函数设计.md §1
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(); // 可信用户标识
  const usersCol = db.collection('users');
  const dogsCol = db.collection('dogs');

  // 1. 查用户，不存在则建档
  let userInfo;
  const userRes = await usersCol.where({ _openid: OPENID }).limit(1).get();
  if (userRes.data.length === 0) {
    const now = Date.now();
    const doc = {
      _openid: OPENID,
      nickname: '铲屎官',
      avatar: '',
      walkCount: 0,
      joinedAt: now,
      createdAt: now,
    };
    const addRes = await usersCol.add({ data: doc });
    userInfo = { _id: addRes._id, ...doc };
  } else {
    userInfo = userRes.data[0];
  }

  // 2. 是否已有狗狗 → 决定前端跳建档(0b)还是首页(1)
  const countRes = await dogsCol.where({ _openid: OPENID }).count();
  const hasDog = countRes.total > 0;

  return {
    ok: true,
    data: {
      userInfo: {
        openid: OPENID,
        nickname: userInfo.nickname,
        avatar: userInfo.avatar,
        walkCount: userInfo.walkCount,
        joinedAt: userInfo.joinedAt,
      },
      hasDog,
    },
  };
};