import type { MessageRequest, MessageResponse } from '@/types/im'
import { readonly, ref } from 'vue'
import { MessageType } from '@/types/im'
import { useUserStore } from './user'

interface UseWebSocketOptions {
  url: string
  heartbeatInterval?: number
  pongTimeout?: number
  reconnectInterval?: number
  maxReconnectTimes?: number
}

/* ================== 单例 ================== */
let singleton: ReturnType<typeof createWebSocket> | null = null

function createWebSocket(options?: Partial<UseWebSocketOptions>) {
  const userStore = useUserStore()
  /* ================== 配置 ================== */
  const config: Required<UseWebSocketOptions> = {
    url:
      options?.url
      || import.meta.env.VITE_WEBSOCKET_BASEURL
      || 'ws://127.0.0.1:8090/ws',

    heartbeatInterval: options?.heartbeatInterval ?? 15_000,
    pongTimeout: options?.pongTimeout ?? 5_000,
    reconnectInterval: options?.reconnectInterval ?? 3_000,
    maxReconnectTimes: options?.maxReconnectTimes ?? 5,
  }

  /* ================== 状态 ================== */
  let ws: WebSocket | null = null

  const connected = ref(false)
  const authenticated = ref(false)

  let cachedToken: string | null = userStore.token

  let heartbeatTimer: number | null = null
  let pongTimeoutTimer: number | null = null
  let reconnectTimer: number | null = null

  let reconnectTimes = 0
  let manualClose = false

  /* ================== 外部消息回调 ================== */
  const messageHandlers: Array<(msg: MessageResponse) => void> = []

  /* ================== 连接管理 ================== */

  function connect() {
    if (ws && (ws.readyState === WebSocket.OPEN || ws.readyState === WebSocket.CONNECTING)) {
      console.log('[WebSocket] 已存在连接或正在连接，跳过')
      return
    }

    console.log('[WebSocket] 开始建立连接')
    manualClose = false

    ws = new WebSocket(config.url)

    ws.onopen = () => {
      connected.value = true
      reconnectTimes = 0

      console.log('[WebSocket] 连接成功')

      startHeartbeat()

      // 自动重新登录
      if (cachedToken) {
        console.log('[WebSocket] 自动重新发送 LOGIN')
        login(cachedToken)
      }
    }

    ws.onmessage = (evt) => {
      const msg: MessageResponse = JSON.parse(evt.data)

      console.log('===收到消息===')
      console.log(msg)

      handleMessage(msg)
    }

    ws.onclose = () => {
      console.warn('[WebSocket] 连接关闭')

      connected.value = false
      authenticated.value = false

      stopHeartbeat()
      stopPongTimeout()

      ws = null

      if (!manualClose) {
        tryReconnect()
      }
    }

    ws.onerror = (err) => {
      console.error('[WebSocket] 连接错误', err)
    }
  }

  function close() {
    console.log('[WebSocket] 主动关闭连接')

    manualClose = true
    stopHeartbeat()
    stopPongTimeout()
    clearReconnectTimer()

    ws?.close()
    ws = null
  }

  /* ================== 重连 ================== */

  function tryReconnect() {
    if (reconnectTimer || reconnectTimes >= config.maxReconnectTimes)
      return

    reconnectTimes++
    console.warn(`[WebSocket] 第 ${reconnectTimes} 次重连中...`)

    reconnectTimer = window.setTimeout(() => {
      reconnectTimer = null
      connect()
    }, config.reconnectInterval)
  }

  function clearReconnectTimer() {
    if (reconnectTimer) {
      clearTimeout(reconnectTimer)
      reconnectTimer = null
    }
  }

  /* ================== 心跳 ================== */

  function startHeartbeat() {
    stopHeartbeat()

    heartbeatTimer = window.setTimeout(() => {
      sendRaw(MessageType.PING)
      startPongTimeout()
      startHeartbeat()
    }, config.heartbeatInterval)
  }

  function stopHeartbeat() {
    if (heartbeatTimer) {
      clearTimeout(heartbeatTimer)
      heartbeatTimer = null
    }
  }

  function startPongTimeout() {
    stopPongTimeout()

    pongTimeoutTimer = window.setTimeout(() => {
      console.error('[WebSocket] 心跳超时，断开连接')
      ws?.close()
    }, config.pongTimeout)
  }

  function stopPongTimeout() {
    if (pongTimeoutTimer) {
      clearTimeout(pongTimeoutTimer)
      pongTimeoutTimer = null
    }
  }

  /* ================== 发送 ================== */

  function sendRaw(type: MessageType, data?: any, to?: any) {
    if (!ws || ws.readyState !== WebSocket.OPEN) {
      console.warn('[WebSocket] 发送失败，未连接')
      return
    }

    const msg: MessageRequest = {
      type,
      from: userStore.user.id,
      to: to ?? null,
      timestamp: Date.now(),
      data: data ?? null,
    }

    ws.send(JSON.stringify(msg))
  }

  function send(type: MessageType, data?: any, to?: any) {
    if (!authenticated.value && type !== MessageType.LOGIN) {
      console.warn('[WebSocket] 未 LOGIN，禁止发送业务消息')
      return
    }
    sendRaw(type, data, to)
  }

  /* ================== 登录相关 ================== */
  function login(token: string) {
    console.log('触发login：', authenticated.value)

    if (!connected.value || authenticated.value)
      return
    cachedToken = token
    sendRaw(MessageType.LOGIN, { token })
  }

  function logout() {
    cachedToken = null
    authenticated.value = false
  }

  /* ================== 消息处理（核心修改点） ================== */

  function handleMessage(msg: MessageResponse) {
    switch (msg.type) {
      case MessageType.PONG:
        stopPongTimeout()
        return

      case MessageType.LOGIN:
        authenticated.value = true
        console.log('[WebSocket] LOGIN 成功')
        return

      case MessageType.LOGOUT:
        authenticated.value = false
        console.log('[WebSocket] 已 LOGOUT')
        return

      default:
        // 所有业务消息交给外部
        messageHandlers.forEach(cb => cb(msg))
    }
  }

  /* ================== 对外订阅 ================== */

  function onMessage(handler: (msg: MessageResponse) => void) {
    messageHandlers.push(handler)
  }

  /* ================== 业务 API ================== */

  function sendPrivate(toUserId: number, content: string) {
    send(MessageType.PRIVATE, { content }, toUserId)
  }

  function sendGroup(groupId: number, content: string) {
    send(MessageType.GROUP, { groupId, content })
  }

  /* ================== 初始化 ================== */

  connect()

  return {
    connect,
    close,

    login,
    logout,

    sendPrivate,
    sendGroup,

    onMessage,

    connected: readonly(connected),
    authenticated: readonly(authenticated),
  }
}

/* ================== 对外 ================== */

export function useWebSocket(options?: Partial<UseWebSocketOptions>) {
  if (!singleton) {
    singleton = createWebSocket(options)
  }
  return singleton
}