const my = { 
  socket : undefined,  
  reconnecting: undefined,
  listeners: {}
}

module.exports={
  initSocket(url){
    if (!my.socket || my.socket.readyState!==my.socket.OPEN && typeof(url)==='string') {
      console.log('WebSocket connecting...')
      my.socket = uni.connectSocket({
        url: url.replace(/^http/, 'ws'),
        complete: ()=>{}
      })
      my.socket.onOpen((res)=>{ 
        console.log('WebSocket onOpen: ', res) 
        clearInterval(my.reconnecting)
        delete my.reconnecting
      })
      my.socket.onClose((res)=>{
        console.log('Websocket onClose: ', res)
        if (!my.reconnecting)
          my.reconnecting = setInterval(()=>{
            console.log(new Date().toJSON(), 'WebSocket reconnecting...')
            this.initSocket(url)
          }, 5000) // 每5秒尝试重连
      })
      my.socket.onError((err)=>{
        console.log('Websocket onError: ', err)
      })
      my.socket.onMessage(({data})=>{ // 在这里统一分发消息（用户端通常不需要返回结果给服务器，因此不用 rpc 模式，而用 event 模式。
        try {
          let dataObj = JSON.parse(data)
          console.log('WebSocket onMessage for skevent: ', dataObj.skevent)
          let listeners = my.listeners[dataObj.skevent] || []
          for (let listener of listeners) {
            listener(dataObj)
          }
        }catch(exception){
          console.log(new Date().toJSON(), 'unknown message', data)
          return
        }
        
      })
    }
    return my.socket
  },
  closeSocket(){
    if (my.socket) my.socket.close()
    setTimeout(()=>{
      clearInterval(my.reconnecting)
      delete my.reconnecting      
    }, 2000)
  },
  addListener(skevent, listener){
    if (Array.isArray(my.listeners[skevent]) && typeof(listener)==='function') {
      my.listeners[skevent].push(listener)
    }else {
      my.listeners[skevent]=[listener]
    }
    return this
  },
  sendObject(data){
    if (typeof(data)!=='string'){
      data=JSON.stringify(data)
    }
    if (my.socket && my.socket.readyState===my.socket.OPEN){
      my.socket.send({data})
    }
  }
}