const ws = require('ws')
const webtoken = require('wo-base-webtoken')

const my = {
  wsServer: undefined,
  socketPool: {},
  listeners: {},
}

module.exports = {
  initSocket (webServer) {
    my.wsServer = new ws.Server({ server: webServer })
    //console.info({ _at: new Date().toJSON(), _from: 'Socket:initSocket', _type: 'CLOG', about: 'Base Socket Server is initialized.' }, '\n,')

    my.wsServer.on('connection', (socket, req) => {
      //console.info({_at:new Date().toJSON(), _from: 'basesocket:onConnection', _type:'CLOG', about: `A socket is connecting from ${req.connection.remoteAddress}:${req.connection.remotePort}.`},'\n,')

      // socket.isAlive = true
      // socket.on('pong', function() { this.isAlive = true })

      socket.on('message', (data) => {
        // 在这里统一分发消息
        let dataObj
        try {
          dataObj = JSON.parse(data)
          if (dataObj?.skevent === 'PING') {
            return
          }
          //console.log({ _at: new Date().toJSON(), _from: 'basesocket:onMessage', _type: 'CLOG', usid: socket.usid, skevent: dataObj?.skevent }, '\n,')
        } catch (exception) {
          console.error({ _at: new Date().toJSON(), _from: 'basesocket:onMessage', _type: 'CERROR', about: 'Unable to parse socket message', data }, '\n,')
          return
        }
        if (['SOCKET_OWNER', 'SOCKET_OWNER_RECONNECT'].includes(dataObj.skevent)) {
          // 前端断线重连时，并不会自动再次提供 _passtoken。在前端的initSocket时，应当把_passtoken送过来，而后台则对_passtoken做验证后再加socketPool。
          dataObj._passtokenSource = webtoken.verifyToken(dataObj._passtoken)
          if (typeof dataObj._passtokenSource?.usid === 'string') {
            my.socketPool[dataObj._passtokenSource.usid] = socket
            socket.usid = dataObj._passtokenSource.usid
            // console.log({
            //   _at: new Date().toJSON(), _from: 'basesocket:onMessage', _type: 'CLOG',
            //   skevent: dataObj.skevent,
            //   usid: dataObj._passtokenSource.usid,
            //   socketPool: Object.keys(my.socketPool)?.length,
            //   socketClients: my.wsServer.clients.size
            // }, '\n,')
          }
        }

        const listeners = my.listeners[dataObj.skevent] || []
        for (const listener of listeners) {
          listener(dataObj)
        }
      })

      // const heartbeat = setInterval(() => {
      //   my.wsServer.clients.forEach((socket) => {
      //     if (socket.isAlive === false) return socket.terminate()
      //     socket.isAlive = false
      //     socket.ping(function() { wo.cclog('👉 ASS: sent Ping') })
      //   })
      // }, 60000)

      socket.on('close', () => {
        //console.log({_at:new Date().toJSON(), _from: 'basesocket:onClose', _type:'CLOG', usid: socket?.usid},'\n,') // don't know why, but this output happens too often without usid.
        delete my.socketPool[socket?.usid]
        // clearInterval(heartbeat)
      })
    })

    return this
  },

  removeUserSocket (usid) {
    delete my.socketPool[usid]
  },

  addListener (skevent, listener) {
    if (Array.isArray(my.listeners[skevent]) && typeof listener === 'function') {
      my.listeners[skevent].push(listener)
    } else {
      my.listeners[skevent] = [listener]
    }
    return this
  },

  sendToAll (dataObj) {
    my.wsServer.clients.forEach((socket) => {
      //if (socket.readyState === socket.OPEN) {
      try {
        socket.send(typeof dataObj !== 'string' ? JSON.stringify(dataObj) : dataObj)
      } catch (expt) {
        console.error(
          {
            _at: new Date().toJSON(),
            _from: 'Socket:sendToAll',
            _type: 'CWARN',
            msg: 'sendToAll: Failed sending to unconnected socket',
            dataObj,
            usid: socket.usid,
          },
          '\n,'
        )
        delete my.socketPool[socket.usid]
      }
    })
  },

  sendToOne (dataObj, usid) {
    const socket = my.socketPool[usid]
    // if (socket && socket.readyState === socket.OPEN) { // 20240916 注意到，前端显示仍然连接着 socket，但后台却判断为不是 OPEN。所以把 if 改成 try.
    try {
      socket.send(typeof dataObj !== 'string' ? JSON.stringify(dataObj) : dataObj)
    } catch (expt) {
      console.error(
        { _at: new Date().toJSON(), _from: 'Socket:sendToOne', _type: 'CWARN', msg: 'sendToOne: Failed sending to unconnected socket', dataObj, usid },
        '\n,'
      )
      delete my.socketPool[usid]
    }
  },
}