const queryString = require('query-string')
//應用授權作用域，snsapi_base （不彈出授權頁面，直接跳轉，只能獲取用戶openid），snsapi_userinfo （彈出授權頁面，可通過openid拿到昵稱、性別、所在地。并且，即使在未關注的情況下，只要用戶授權，也能獲取其信息）
const SCOPES = ['snsapi_base', 'snsapi_userinfo']


class VueWechatAuthPlugin {

 install(Vue, options) {
  let wechatAuth = this
  this.setAppId(options.appid)
  Vue.mixin({
   created: function () {
    this.$wechatAuth = wechatAuth
   }
  })

 }

 constructor() {
  this.appid = null
  this.redirect_uri = null
  this.scope = SCOPES[1]
  this._code = null
  this._redirect_uri = null
 }

 static makeState() {
  return Math.random().toString(36).substring(2, 15) + Math.random().toString(36).substring(2, 15)
 }

 setAppId(appid) {
  this.appid = appid
 }

 set redirect_uri(redirect_uri) {
  this._redirect_uri = encodeURIComponent(redirect_uri)
 }

 get redirect_uri() {
  return this._redirect_uri
 }

 get state() {
  return localStorage.getItem("wechat_auth:state")
 }

 set state(state) {
  localStorage.setItem("wechat_auth:state", state)
 }

 get authUrl() {
  if (this.appid === null) {
   throw "appid must not be null"
  }
  if (this.redirect_uri === null) {
   throw "redirect uri must not be null"
  }
  this.state = VueWechatAuthPlugin.makeState()
  return `https://open.weixin.qq.com/connect/oauth2/authorize?appid=${this.appid}&redirect_uri=${this.redirect_uri}&response_type=code&scope=${this.scope}&state=${this.state}#wechat_redirect`
 }

 returnFromWechat(redirect_uri) {
  let parsedUrl = queryString.parse(redirect_uri.split('?')[1])
  if (process.env.NODE_ENV === 'development') {
   // console.log('parsedUrl: ', parsedUrl)
   this.state = null
   this._code = parsedUrl.code
  } else {
   if (this.state === null) {
    throw "You did't set state"
   }
   if (parsedUrl.state === this.state) {
    this.state = null
    this._code = parsedUrl.code
   } else {
    this.state = null
    throw `Wrong state: ${parsedUrl.state}`
   }
  }
 }

 get code() {
  if (this._code === null) {
   throw "Not get the code from wechat server!"
  }
  // console.log(this)
  // console.log('this._code: ' + this._code)
  let code = this._code
  this._code = null
  // console.log('code: ' + code)
  return code
 }
}

const vueWechatAuthPlugin = new VueWechatAuthPlugin()

export default vueWechatAuthPlugin

import wechatAuth from './plugins/wechatAuth'//微信登錄插件
const queryString = require('query-string');

Vue.use(wechatAuth, {appid: XXXXXXXXX});

router.beforeEach((to, from, next) => {
 if (store.state.loginStatus == 0) {
  //微信未授權登錄跳轉到授權登錄頁面
  let url = window.location.href;
  //解決重復登錄url添加重復的code與state問題
  let parseUrl = queryString.parse(url.split('?')[1]);
  let loginUrl;
  if (parseUrl.code && parseUrl.state) {
   delete parseUrl.code;
   delete parseUrl.state;
   loginUrl = `${url.split('?')[0]}?${queryString.stringify(parseUrl)}`;
  } else {
   loginUrl = url;
  }
  wechatAuth.redirect_uri = loginUrl;
  store.dispatch('setLoginStatus', 1);
  window.location.href = wechatAuth.authUrl
 } else if (store.state.loginStatus == 1) {
  try {
   wechatAuth.returnFromWechat(to.fullPath);
  } catch (err) {
   store.dispatch('setLoginStatus', 0)
   next()
  }
  store.dispatch('loginWechatAuth', wechatAuth.code).then((res) => {
   if (res.status == 1) {
    store.dispatch('setLoginStatus', 2)
   } else {
    store.dispatch('setLoginStatus', 0)
   }
   next()
  }).catch((err) => {
   next()
  })
 }else {
  next()
 }
});