gistfile1.txt

> ./utax/On.js
  ./utax/assign.js
  ./lib/SDK.js
  ./utax/web/tld.js
  ./utax/sleep.js

+ USER, INIT_RESOLVE, TAB_ID, _setUser, unbindBeforeunload

same_host = do =>
  dot_host = '.'+tld
  (origin)=>
    {hostname} = new URL(origin)
    hostname == tld or hostname.endsWith(dot_host)

liSet = (li,to)=>
  li.splice(0,li.length,...to)
  return

li2user = (li)=>
  if li
    [id,name] = li
    return {id,name}
  {}

liEq = (a,b)=>
  r = a?.length == b?.length
  if a and r
    return a.every (i,p)=>i==b[p]
  r

ON_USER_CHANGE = new Set()

_setMe = (me)=>
  USER = li2user me
  for f from ON_USER_CHANGE
    f(USER)
  return

_update = =>
  replyMsgNew(0)
  _setMe USER_SIGNIN[0]
  return

_setSigninExit = (signin,exit)=>
  liSet USER_SIGNIN,signin
  liSet USER_EXIT,exit
  return

_updateUser = (signin,exit)=>
  pre = USER_SIGNIN[0]
  now = signin[0]
  _setSigninExit signin,exit
  if not liEq pre, now
    _update()
  return

INIT = new Promise (resolve)=>
  _setUser = INIT_RESOLVE = (signin, exit)=>
    INIT_RESOLVE = INIT = undefined
    _setSigninExit signin,exit
    _setMe signin[0]
    _setUser = _updateUser
    resolve()
    return
  return

< CHANNEL = new BroadcastChannel 'user.tax:'+tld

_ms = =>
  parseInt +new Date

MSG_ID = 0

LEADER = 0
MSG_NEW = 1

< USER_SIGNIN = []
< USER_EXIT = []

NEW_REPLY = []

replyMsgNew = (tab_id)=>
  CHANNEL.postMessage [
    MSG_NEW
    tab_id
    TAB_ID
    USER_SIGNIN
    USER_EXIT
  ]
  return

initPost = =>
  TAB_ID = _ms()
  CHANNEL.postMessage [
    MSG_NEW
    TAB_ID
  ]
  return


On CHANNEL,{
  message:(e)=>
    {data,origin} = e
    if not same_host origin
      return

    {length} = data

    switch data[0]
      when MSG_NEW
        tab_id = data[1]
        if length == 2
          if INIT_RESOLVE
            return
          if LEADER
            replyMsgNew tab_id
          else
            data.push _ms()
            NEW_REPLY.push data
            timeout = 10
            await sleep timeout
            if NEW_REPLY.length
              li = NEW_REPLY.filter(
                (i)=>
                  time = i[2]
                  timeout = (new Date - time) >= timeout
                  if timeout
                    replyMsgNew(i[1])
                  !timeout
              )
              if li.length != NEW_REPLY.length
                NEW_REPLY = li
                if not LEADER
                  LEADER = 1
                  # document.title = 'leader'
                  unbindBeforeunload = On window,{
                    beforeunload:=>
                      # 重新选举避免延时(没有leader的时候，延时甚至可能会高达1秒)
                      initPost()
                      return
                  }
        else
          user_li = data[3..]

          _setUser ...user_li

          src_id = data[2]
          if src_id == TAB_ID
            initPost()

          for i,pos in NEW_REPLY
            if i[1] == tab_id
              NEW_REPLY.splice(pos,1)
              return
          if tab_id and LEADER
            if src_id <= TAB_ID
              # document.title = 'member'
              unbindBeforeunload()
              unbindBeforeunload = undefined
              LEADER = 0
    return
}


do =>
  initPost()
  await sleep 300
  if INIT_RESOLVE
    _setUser ... await SDK.u()
  return

< onUserChange = (func)=>
  ON_USER_CHANGE.add func
  if USER != undefined
    func USER
  =>
    ON_USER_CHANGE.delete func
    return

< userSet = (li)=>
  r = Array.isArray(li)
  if r
    uid = li[0]

    for [id],pos in USER_EXIT
      if uid == id
        USER_EXIT.splice(pos,1)
        USER_SIGNIN.unshift(li)
        _update()
        return r

    for [id],pos in USER_SIGNIN
      if uid == id
        if pos == 0
          break
        USER_SIGNIN.splice pos, 1
        USER_SIGNIN.unshift li
        _update()
        return r
    USER_SIGNIN.unshift li
    _update()
  return r

< exit = ()=>
  {id} = await User()
  if id
    return exitUid(id)
  return

< exitUid = (id)=>
  for i,pos in USER_SIGNIN
    if i[0] == id
      await SDK.u.exit id
      USER_SIGNIN.splice pos,1
      _update()
      return
  return

_User = =>
  await INIT
  _User = => USER
  USER

< default User = =>
  _User()