/**
 * 简化的 WebSocket 管理器（Web 版）
 * 专门负责 WebSocket 连接和消息传输，不包含打字机逻辑
 */

import { IdUtils, CallbackUtils, MessageUtils, TimerUtils } from './index'

/* =======================
 * 类型定义
 * ======================= */

export interface WebSocketCallbacks {
  onConnect?: (event?: Event) => void
  onDisconnect?: (event?: CloseEvent) => void
  onError?: (error: any) => void
  onMessage?: (message: any) => void
  getConversationId?: () => string
  getAgentId?: () => string
}

export interface WebSocketManagerOptions extends WebSocketCallbacks {
  wsUrl?: string
  protocols?: string[]
  reconnectInterval?: number
  maxReconnectAttempts?: number
  heartbeatInterval?: number
  messageId?: string
  baseDelay?: number
  retries?: number
  maxDelay?: number
  tryReconnect?: boolean
}

export interface QueuedMessage {
  [key: string]: any
  retryCount?: number
  timestamp?: number
}

export interface WebSocketStats {
  messagesReceived: number
  messagesSent: number
  messagesDropped: number
  reconnectCount: number
  connectionStartTime: number | null
  lastMessageTime: number | null
}

/* =======================
 * WebSocketManager
 * ======================= */

export class WebSocketManager {
  private wsUrl = ''
  private protocols: string[] = []
  private reconnectInterval = 3000
  private maxReconnectAttempts = 5
  private heartbeatInterval = 30000

  private ws: WebSocket | null = null
  private reconnectAttempts = 0
  private isConnecting = false
  private connectionState = false

  private heartbeatTimer: number | null = null
  private reconnectTimer: number | null = null

  private callbacks: Required<WebSocketCallbacks>

  private messageQueue: QueuedMessage[] = []

  private stats: WebSocketStats = {
    messagesReceived: 0,
    messagesSent: 0,
    messagesDropped: 0,
    reconnectCount: 0,
    connectionStartTime: null,
    lastMessageTime: null,
  }

  constructor(options: WebSocketManagerOptions = {}) {
    this.wsUrl = options.wsUrl ?? ''
    this.protocols = options.protocols ?? []
    this.reconnectInterval = options.reconnectInterval ?? 3000
    this.maxReconnectAttempts = options.maxReconnectAttempts ?? 5
    this.heartbeatInterval = options.heartbeatInterval ?? 30000

    this.callbacks = {
      onConnect: options.onConnect ?? (() => { }),
      onDisconnect: options.onDisconnect ?? (() => { }),
      onError: options.onError ?? (() => { }),
      onMessage: options.onMessage ?? (() => { }),
      getConversationId: options.getConversationId ?? (() => ''),
      getAgentId: options.getAgentId ?? (() => ''),
    }
  }

  /* =======================
   * 内部工具
   * ======================= */

  private safeCall(name: keyof WebSocketCallbacks, ...args: any[]): void {
    CallbackUtils.safeCall(this.callbacks, name as string, ...args)
  }

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

  async init(wsUrl?: string): Promise<void> {
    if (wsUrl) this.wsUrl = wsUrl
    if (!this.wsUrl) throw new Error('WebSocket URL is required')
    await this.connect()
  }

  // 改进方案：让connect()真正等待连接
  async connect(): Promise<void> {
    console.log('[WebSocket] connect() called, isConnecting:', this.isConnecting, 'connectionState:', this.connectionState)
    if (this.isConnecting || this.connectionState) {
      console.log('[WebSocket] Already connecting or connected, returning early')
      return
    }
    this.isConnecting = true
    console.log('[WebSocket] Starting connection...')

    return new Promise((resolve, reject) => {
      try {
        console.log('[WebSocket] About to create new WebSocket with URL:', this.wsUrl)
        this.ws = new WebSocket(this.wsUrl, this.protocols)
        console.log('[WebSocket] WebSocket object created, readyState:', this.ws?.readyState)

        // 包装handleOpen以resolve Promise
        this.ws.onopen = (event: Event) => {
          console.log('[WebSocket] onopen event fired')
          this.handleOpen(event)
          resolve()  // ← 真正的连接成功
        }

        this.ws.onmessage = this.handleMessage
        this.ws.onclose = (event: CloseEvent) => {
          console.log('[WebSocket] onclose event fired, code:', event.code, 'reason:', event.reason)
          this.handleClose(event)
        }
        this.ws.onerror = (error: Event) => {
          console.log('[WebSocket] onerror event fired', error)
          this.handleError(error)
          reject(error)  // ← Promise拒绝
        }
      } catch (error) {
        this.isConnecting = false
        this.safeCall('onError', error)
        this.scheduleReconnect()
        reject(error)
      }
    })
  }

  private handleOpen = (event: Event): void => {
    this.isConnecting = false
    this.connectionState = true
    this.reconnectAttempts = 0
    this.stats.connectionStartTime = Date.now()

    this.startHeartbeat()
    this.safeCall('onConnect', event)
    this.processQueue()
  }

  private handleMessage = (event: MessageEvent): void => {
    const raw = event.data
    if (MessageUtils.isPongMessage(raw)) return

    const data =
      typeof raw === 'string'
        ? MessageUtils.safeParseJSON(raw)
        : raw

    if (!data) return

    this.stats.messagesReceived++
    this.stats.lastMessageTime = Date.now()

    this.safeCall('onMessage', data)
  }

  private handleClose = (event: CloseEvent): void => {
    this.connectionState = false
    this.isConnecting = false
    this.stopHeartbeat()

    this.safeCall('onDisconnect', event)

    if (event.code !== 1000 && this.reconnectAttempts < this.maxReconnectAttempts) {
      this.scheduleReconnect()
    }
  }

  private handleError = (error: Event): void => {
    this.connectionState = false
    this.isConnecting = false

    this.safeCall('onError', {
      type: 'WEBSOCKET_ERROR',
      error,
    })

    if (!this.reconnectTimer) {
      this.scheduleReconnect()
    }
  }

  /* =======================
   * 消息发送
   * ======================= */

  sendMessage(message: QueuedMessage): boolean {
    const data = {
      ...message,
      timestamp: Date.now(),
      retryCount: message.retryCount ?? 0,
    }

    if (!this.isConnected()) {
      this.messageQueue.push(data)
      this.connect()
      return false
    }

    try {
      this.ws!.send(JSON.stringify(data))
      this.stats.messagesSent++
      return true
    } catch (error) {
      this.messageQueue.push(data)
      this.safeCall('onError', error)
      return false
    }
  }

  private processQueue(): void {
    while (this.messageQueue.length) {
      const msg = this.messageQueue.shift()!
      if ((msg.retryCount ?? 0) >= 3) {
        this.stats.messagesDropped++
        continue
      }
      msg.retryCount = (msg.retryCount ?? 0) + 1
      this.sendMessage(msg)
    }
  }

  /* =======================
   * 心跳 & 重连
   * ======================= */

  private startHeartbeat(): void {
    this.stopHeartbeat()
    this.heartbeatTimer = window.setInterval(() => {
      if (!this.isConnected()) return

      this.sendMessage({
        messageType: '3',
        messageContent: 'heartbeat',
        messageId: IdUtils.generateMessageId(),
        conversationId: this.callbacks.getConversationId(),
        agentId: this.callbacks.getAgentId(),
      })
    }, this.heartbeatInterval)
  }

  private stopHeartbeat(): void {
    this.heartbeatTimer = TimerUtils.clearTimer(this.heartbeatTimer, 'interval')
  }

  private scheduleReconnect(): void {
    if (this.reconnectAttempts >= this.maxReconnectAttempts) return

    this.reconnectAttempts++
    this.stats.reconnectCount++

    const delay = Math.min(
      this.reconnectInterval * Math.pow(1.5, this.reconnectAttempts - 1),
      30000
    )

    this.reconnectTimer = window.setTimeout(() => {
      this.reconnectTimer = null
      this.connect()
    }, delay)
  }

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

  isConnected(): boolean {
    return (
      this.connectionState &&
      !!this.ws &&
      this.ws.readyState === WebSocket.OPEN
    )
  }

  getStats() {
    return {
      ...this.stats,
      queueLength: this.messageQueue.length,
      isConnected: this.isConnected(),
    }
  }

  close(): void {
    this.stopHeartbeat()
    TimerUtils.clearTimer(this.reconnectTimer)
    this.reconnectTimer = null

    this.ws?.close(1000)
    this.ws = null

    this.connectionState = false
    this.isConnecting = false
    this.messageQueue = []
  }

  destroy(): void {
    this.close()
  }
}

export default WebSocketManager