const my = {
  socket: undefined,
  reconnecting: undefined,
  heartbeating: undefined,
  listeners: {},
  heartbeatInterval: 20000,
  reconnectInterval: 5000,
  messageQueue: [],
}

// uni.onSocket* 和 sendSocketMessage/closeSocket 方法，是全局唯一的 api，不需要保存 socket 对象。
// SocketTask 的 on* 和 send/close 方法，是针对具体 socket 的，适用于多个连接（但不一定支持）或者需要对唯一连接做更精细控制。

export default {
  isAlive () {
    return my.socket && my.socket.readyState === my.socket.OPEN
  },
  initSocket ({ url, relogin = false, stateManager = {}, heartbeat = false, heartbeatInterval, reconnectInterval } = {}) {
    if (!my.socket || (my.socket.readyState !== my.socket.OPEN && typeof url === 'string')) {
      console.log({ _at: new Date().toJSON(), about: `WebSocket is connecting to ${url}...` })
      my.socket = uni.connectSocket({
        url: url.replace(/^http/, 'ws'),
        complete: () => {},
      })
      my.socket.onOpen((res) => {
        console.log({ _at: new Date().toJSON(), about: 'WebSocket onOpen: ', res })
        stateManager.socketAlive = true

        if (my.messageQueue.length) {
          console.log('WebSocket_onOpen: sending messageQueue')
          my.messageQueue.forEach((dataObj) => {
            this.sendObject(dataObj)
          })
          my.messageQueue = []
        }

        clearInterval(my.reconnecting)
        delete my.reconnecting

        // 前端断线重连时，并不会自动提供 _passtoken，应当把_passtoken送给后台，而后台则对_passtoken做验证后再加socketPool。
        if (relogin && uni.getStorageSync('_passtoken')) {
          console.log({ _at: new Date().toJSON(), about: 'Reporting owner for reconnecting socket' })
          my.socket.send({ data: JSON.stringify({ skevent: 'SOCKET_OWNER_RECONNECT', _passtoken: uni.getStorageSync('_passtoken') }) })
        }

        if (heartbeat) {
          my.heartbeating = setInterval(() => {
            if (my.socket && my.socket.readyState === my.socket.OPEN) {
              my.socket.send({ data: JSON.stringify({ skevent: 'PING' }) })
            } else {
              clearInterval(my.heartbeating)
              delete my.heartbeating
            }
          }, heartbeatInterval || my.heartbeatInterval) // 定期发送心跳，避免被关闭
        }
      })
      my.socket.onClose((res) => {
        console.log({ _at: new Date().toJSON(), about: 'Websocket onClose: ', res })
        stateManager.socketAlive = false
        if (!my.reconnecting)
          my.reconnecting = setInterval(() => {
            console.log({ _at: new Date().toJSON(), about: 'Websocket reconnecting...' })
            this.initSocket({ url, relogin: true, stateManager })
          }, reconnectInterval || my.reconnectInterval) // 定时尝试重连
      })
      my.socket.onError((err) => {
        console.log({ _at: new Date().toJSON(), about: 'Websocket onError: ', err })
        stateManager.socketAlive = false
      })
      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 { skevent, ...apiWhat } = JSON.parse(data)
          console.log({ _at: new Date().toJSON(), about: 'Websocket onMessage', skevent, apiWhat })
          let listeners = my.listeners[skevent] || []
          for (let listener of listeners) {
            listener(apiWhat)
          }
        } catch (exception) {
          console.log({ _at: new Date().toJSON(), about: 'Websocket onMessage unknown', data, exception })
          return
        }
      })
    }
    return this
  },
  closeSocket () {
    if (my.socket) my.socket.close()
    setTimeout(() => {
      clearInterval(my.reconnecting)
      delete my.reconnecting
    }, 2000)
  },
  initListener (skevent, listener) {
    // 当该 skevent 尚不具有任何 listener 时，添加本 listener
    my.listeners[skevent]?.length > 0 || this.addListener(skevent, listener)
    return this
  },
  addListener (skevent, listener) {
    if (Array.isArray(my.listeners[skevent]) && typeof listener === 'function') {
      my.listeners[skevent].push(listener)
    } else {
      my.listeners[skevent] = [listener]
    }
    return this
  },
  countListener (skevent) {
    if (Array.isArray(my.listeners[skevent])) {
      return my.listeners[skevent].length
    }
    return 0
  },
  sendObject (dataObj = {}) {
    console.log('sendObject! socket.readyState =', my.socket.readyState)
    // 把 sendObject({_passtoken}) 从其他零散地方迁移到这里来
    if (!dataObj._passtoken) {
      dataObj._passtoken = uni.getStorageSync('_passtoken') || undefined
    }
    if (my.socket && my.socket.readyState === my.socket.OPEN) {
      my.socket.send({
        data: typeof dataObj !== 'string' ? JSON.stringify(dataObj) : dataObj,
      })
    } else {
      my.messageQueue.push(dataObj)
    }
  },
}