const requestUtil = require('./request')

let pending = null

function deviceId() {
  let id = wx.getStorageSync('deviceId')
  if (!id) {
    id = Date.now().toString(36) + Math.random().toString(36).slice(2, 8)
    wx.setStorageSync('deviceId', id)
  }
  return id
}

function captureSharer(query) {
  if (!query || !query.sharer) return
  const selfId = wx.getStorageSync('openid')
  if (query.sharer !== selfId) wx.setStorageSync('sharer', query.sharer)
}

function login() {
  return new Promise((resolve, reject) => {
    wx.login({
      success(res) {
        if (!res.code) {
          reject(new Error('微信登录未返回 code'))
          return
        }
        requestUtil
          .request({
            url: '/api/login',
            method: 'POST',
            data: { code: res.code, deviceId: deviceId() }
          })
          .then((data) => {
            wx.setStorageSync('token', data.token)
            wx.setStorageSync('openid', data.openid)
            wx.setStorageSync('loginDemo', !!data.demo)
            resolve(data)
          })
          .catch(reject)
      },
      fail() {
        reject(new Error('微信登录失败'))
      }
    })
  })
}

function ensureLogin() {
  if (wx.getStorageSync('token')) {
    return Promise.resolve({
      token: wx.getStorageSync('token'),
      openid: wx.getStorageSync('openid')
    })
  }
  if (!pending) {
    pending = login().finally(() => {
      pending = null
    })
  }
  return pending
}

function sourceSharer() {
  const sharer = wx.getStorageSync('sharer') || ''
  const openid = wx.getStorageSync('openid') || ''
  if (!sharer || sharer === openid) return ''
  return sharer
}

module.exports = {
  captureSharer: captureSharer,
  ensureLogin: ensureLogin,
  sourceSharer: sourceSharer
}