/**
 * WebSocket 服务管理
 *
 * @description
 * 统一管理应用中的所有 WebSocket 连接
 * - 字典同步 WebSocket
 * - 在线用户计数 WebSocket
 * - 其他业务 WebSocket
 *
 * @author fastapiadmin
 */

import { Auth } from "@utils/auth";

/**
 * WebSocket 服务实例约定接口
 */
type WebSocketService = {
  disconnect?: () => void;
  closeWebSocket?: () => void;
  cleanup?: () => void;
  [key: string]: any;
};

/**
 * 全局 WebSocket 实例管理
 */
const websocketInstances = new Map<string, WebSocketService>();

/**
 * 防止重复初始化的状态标记
 */
let isInitialized = false;

/**
 * 注册 WebSocket 实例
 */
export function registerWebSocketInstance(key: string, instance: WebSocketService) {
  websocketInstances.set(key, instance);
}

/**
 * 获取 WebSocket 实例
 */
export function getWebSocketInstance(key: string) {
  return websocketInstances.get(key);
}

/**
 * 初始化 WebSocket 服务
 */
export function setupWebSocket() {
  if (isInitialized) {
    console.warn("[WebSocket] 已初始化，跳过重复初始化");
    return;
  }

  if (!Auth.getAccessToken()) {
    console.warn("[WebSocket] 未登录，跳过 WebSocket 初始化");
    return;
  }

  try {
    isInitialized = true;
    console.info("[WebSocket] 初始化成功");
  } catch (error) {
    console.error("[WebSocket] 初始化失败:", error);
  }
}

/**
 * 清理所有 WebSocket 连接
 */
export function cleanupWebSocket() {
  console.info("[WebSocket] 开始清理连接...");

  websocketInstances.forEach((instance, key) => {
    try {
      if (instance.disconnect) {
        instance.disconnect();
      } else if (instance.closeWebSocket) {
        instance.closeWebSocket();
      } else if (instance.cleanup) {
        instance.cleanup();
      }
      console.info(`[WebSocket] ${key} 已断开`);
    } catch (error) {
      console.error(`[WebSocket] ${key} 清理失败:`, error);
    }
  });

  websocketInstances.clear();
  isInitialized = false;
  console.info("[WebSocket] 清理完成");
}

/**
 * 重新初始化 WebSocket
 */
export function reinitializeWebSocket() {
  cleanupWebSocket();
  setupWebSocket();
}

if (typeof window !== "undefined") {
  window.addEventListener("beforeunload", () => {
    cleanupWebSocket();
  });
}

/**
 * WebSocket 客户端类
 *
 * 提供 WebSocket 连接管理功能，支持自动重连、心跳检测和消息队列
 *
 * @module utils/socket
 */

interface WebSocketOptions {
  url?: string;
  messageHandler: (event: MessageEvent) => void;
  reconnectInterval?: number; // 重连间隔(ms)
  heartbeatInterval?: number; // 心跳检测间隔(ms)
  pingInterval?: number; // 发送ping间隔(ms)
  reconnectTimeout?: number; // 重连超时时间(ms)
  maxReconnectAttempts?: number; // 最大重连次数
  connectionTimeout?: number; // 连接建立超时时间(ms)
}

export default class WebSocketClient {
  private static instance: WebSocketClient | null = null;
  private ws: WebSocket | null = null;
  private url: string;
  private messageHandler: (event: MessageEvent) => void;
  private reconnectInterval: number;
  private heartbeatInterval: number;
  private pingInterval: number;
  private reconnectTimeout: number;
  private maxReconnectAttempts: number;
  private connectionTimeout: number;
  private reconnectAttempts: number = 0; // 当前重连次数

  // 消息队列 - 缓存连接建立前的消息
  private messageQueue: Array<string | ArrayBufferLike | Blob | ArrayBufferView> = [];

  // 定时器
  private detectionTimer: NodeJS.Timeout | null = null;
  private timeoutTimer: NodeJS.Timeout | null = null;
  private reconnectTimer: NodeJS.Timeout | null = null;
  private pingTimer: NodeJS.Timeout | null = null;
  private connectionTimer: NodeJS.Timeout | null = null; // 连接超时定时器

  // 状态标识
  private isConnected: boolean = false;
  private isConnecting: boolean = false; // 是否正在连接中
  private stopReconnect: boolean = false;
  private isReconnecting: boolean = false;

  private constructor(options: WebSocketOptions) {
    this.url = options.url || (process.env.VUE_APP_LOGIN_WEBSOCKET as string);
    this.messageHandler = options.messageHandler;
    this.reconnectInterval = options.reconnectInterval ?? 20 * 1000; // 默认20秒
    this.heartbeatInterval = options.heartbeatInterval ?? 5 * 1000; // 默认5秒
    this.pingInterval = options.pingInterval ?? 10 * 1000; // 默认10秒
    this.reconnectTimeout = options.reconnectTimeout ?? 30 * 1000; // 默认30秒
    this.maxReconnectAttempts = options.maxReconnectAttempts ?? 10; // 默认最多重连10次
    this.connectionTimeout = options.connectionTimeout ?? 10 * 1000; // 连接超时10秒
  }

  // 单例模式获取实例
  static getInstance(options: WebSocketOptions): WebSocketClient {
    if (!WebSocketClient.instance) {
      WebSocketClient.instance = new WebSocketClient(options);
    } else {
      // 更新消息处理器
      WebSocketClient.instance.messageHandler = options.messageHandler;
      // 如果提供了新的URL，则更新并重新连接
      if (options.url && WebSocketClient.instance.url !== options.url) {
        WebSocketClient.instance.url = options.url;
        WebSocketClient.instance.reconnectAttempts = 0;
        WebSocketClient.instance.init();
      }
    }
    return WebSocketClient.instance;
  }

  // 初始化连接
  init(): void {
    this.connect(true);
  }

  private connect(resetReconnectAttempts: boolean = false): void {
    // 如果正在连接中，不重复连接
    if (this.isConnecting) {
      console.info("正在建立WebSocket连接中...");
      return;
    }

    // 如果已连接，不重复连接
    if (this.ws?.readyState === WebSocket.OPEN) {
      console.warn("WebSocket连接已存在");
      this.flushMessageQueue(); // 确保队列中的消息被发送
      return;
    }

    try {
      this.isConnecting = true;
      this.stopReconnect = false;
      if (resetReconnectAttempts) {
        this.reconnectAttempts = 0;
        this.isReconnecting = false;
        this.clearTimer("reconnectTimer");
      }
      this.ws = new WebSocket(this.url);

      // 设置连接超时检测
      this.clearTimer("connectionTimer");
      this.connectionTimer = setTimeout(() => {
        console.error(`WebSocket连接超时 (${this.connectionTimeout}ms)：${this.url}`);
        this.handleConnectionTimeout();
      }, this.connectionTimeout);

      this.ws.onopen = (event) => this.handleOpen(event);
      this.ws.onmessage = (event) => this.handleMessage(event);
      this.ws.onclose = (event) => this.handleClose(event);
      this.ws.onerror = (event) => this.handleError(event);
    } catch (error) {
      console.error("WebSocket初始化失败:", error);
      this.isConnecting = false;
      this.reconnect();
    }
  }

  // 处理连接超时
  private handleConnectionTimeout(): void {
    if (this.ws?.readyState !== WebSocket.OPEN) {
      console.error("WebSocket连接超时，强制关闭连接");
      this.ws?.close(1000, "Connection timeout");
      this.isConnecting = false;
      this.reconnect();
    }
  }

  // 关闭连接
  close(force?: boolean): void {
    this.clearAllTimers();
    this.stopReconnect = true;
    this.isReconnecting = false;
    this.isConnecting = false;

    if (this.ws) {
      // 1000 表示正常关闭
      this.ws.close(force ? 1001 : 1000, force ? "Force closed" : "Normal close");
      this.ws = null;
    }

    this.isConnected = false;
  }

  // 发送消息 - 增加消息队列
  send(data: string | ArrayBufferLike | Blob | ArrayBufferView, immediate: boolean = false): void {
    // 如果要求立即发送且未连接，则直接报错
    if (immediate && (!this.ws || this.ws.readyState !== WebSocket.OPEN)) {
      console.error("WebSocket未连接，无法立即发送消息");
      return;
    }

    // 如果未连接且不要求立即发送，则加入消息队列
    if (!this.ws || this.ws.readyState !== WebSocket.OPEN) {
      console.info("WebSocket未连接，消息已加入队列等待发送");
      this.messageQueue.push(data);
      // 如果未在重连中，则尝试重连
      if (!this.isConnecting && !this.stopReconnect) {
        this.init();
      }
      return;
    }

    try {
      this.ws.send(data as any);
    } catch (error) {
      console.error("WebSocket发送消息失败:", error);
      // 发送失败时将消息加入队列，等待重连后重试
      this.messageQueue.push(data);
      this.reconnect();
    }
  }

  // 发送队列中的消息
  private flushMessageQueue(): void {
    if (this.messageQueue.length > 0 && this.ws?.readyState === WebSocket.OPEN) {
      console.info(`发送队列中的${this.messageQueue.length}条消息`);
      while (this.messageQueue.length > 0) {
        const data = this.messageQueue.shift();
        if (data) {
          try {
            this.ws?.send(data as any);
          } catch (error) {
            console.error("发送队列消息失败:", error);
            // 如果发送失败，将消息放回队列头部
            if (data) this.messageQueue.unshift(data);
            break;
          }
        }
      }
    }
  }

  // 处理连接打开
  private handleOpen(event: Event): void {
    console.info("WebSocket连接成功", event);
    this.clearTimer("connectionTimer"); // 清除连接超时定时器
    this.isConnected = true;
    this.isConnecting = false;
    this.isReconnecting = false;
    this.stopReconnect = false;
    this.reconnectAttempts = 0; // 重置重连次数
    this.startHeartbeat();
    this.startPing();
    this.flushMessageQueue(); // 发送队列中的消息
  }

  // 处理收到的消息
  private handleMessage(event: MessageEvent): void {
    console.debug("收到WebSocket消息:", event);
    this.resetHeartbeat();
    this.messageHandler(event);
  }

  // 处理连接关闭
  private handleClose(event: CloseEvent): void {
    console.info(
      `WebSocket断开: 代码=${event.code}, 原因=${event.reason}, 干净关闭=${event.wasClean}`
    );

    // 1000 是正常关闭代码
    const isNormalClose = event.code === 1000;

    this.isConnected = false;
    this.isConnecting = false;
    this.clearConnectionTimers();
    this.ws = null;

    if (!this.stopReconnect && !isNormalClose) {
      this.reconnect();
    }
  }

  // 处理错误 - 增加详细错误信息
  private handleError(event: Event): void {
    console.error("WebSocket连接错误:");
    console.error("错误事件:", event);
    console.error(
      "当前连接状态:",
      this.ws?.readyState ? this.getReadyStateText(this.ws.readyState) : "未初始化"
    );

    this.isConnected = false;
    this.isConnecting = false;

    // 只有在未停止重连的情况下才尝试重连
    if (!this.stopReconnect) {
      this.reconnect();
    }
  }

  private closeCurrentSocketForReconnect(): void {
    this.clearConnectionTimers();
    this.isConnected = false;
    this.isConnecting = false;

    if (this.ws) {
      this.ws.onopen = null;
      this.ws.onmessage = null;
      this.ws.onclose = null;
      this.ws.onerror = null;

      if (this.ws.readyState === WebSocket.OPEN || this.ws.readyState === WebSocket.CONNECTING) {
        this.ws.close(1001, "Reconnect");
      }

      this.ws = null;
    }
  }

  // 转换连接状态为文本描述
  private getReadyStateText(state: number): string {
    switch (state) {
      case WebSocket.CONNECTING:
        return "CONNECTING (0) - 正在连接";
      case WebSocket.OPEN:
        return "OPEN (1) - 已连接";
      case WebSocket.CLOSING:
        return "CLOSING (2) - 正在关闭";
      case WebSocket.CLOSED:
        return "CLOSED (3) - 已关闭";
      default:
        return `未知状态 (${state})`;
    }
  }

  // 开始心跳检测
  private startHeartbeat(): void {
    this.clearTimer("detectionTimer");
    this.clearTimer("timeoutTimer");

    this.detectionTimer = setTimeout(() => {
      this.isConnected = this.ws?.readyState === WebSocket.OPEN;

      if (!this.isConnected) {
        console.warn("WebSocket心跳检测失败，尝试重连");
        this.reconnect();

        this.timeoutTimer = setTimeout(() => {
          console.warn("WebSocket重连超时");
          this.close();
        }, this.reconnectTimeout);
      }
    }, this.heartbeatInterval);
  }

  // 重置心跳检测
  private resetHeartbeat(): void {
    this.clearTimer("detectionTimer");
    this.clearTimer("timeoutTimer");
    this.startHeartbeat();
  }

  // 开始发送ping消息
  private startPing(): void {
    this.clearTimer("pingTimer");

    this.pingTimer = setInterval(() => {
      if (this.ws?.readyState !== WebSocket.OPEN) {
        console.warn("WebSocket未连接，停止发送ping");
        this.clearTimer("pingTimer");
        this.reconnect();
        return;
      }

      try {
        this.ws.send("ping");
        console.debug("发送ping消息");
      } catch (error) {
        console.error("发送ping消息失败:", error);
        this.clearTimer("pingTimer");
        this.reconnect();
      }
    }, this.pingInterval);
  }

  // 重连 - 增加重连次数限制
  private reconnect(): void {
    if (this.stopReconnect || this.isConnecting || this.reconnectInterval <= 0) {
      return;
    }

    // 检查是否超过最大重连次数
    if (this.reconnectAttempts >= this.maxReconnectAttempts) {
      console.error(`已达到最大重连次数(${this.maxReconnectAttempts})，停止重连`);
      this.close(true);
      return;
    }

    this.reconnectAttempts++;
    this.isReconnecting = true;
    this.closeCurrentSocketForReconnect();

    const delay = this.calculateReconnectDelay();
    console.info(
      `将在${delay / 1000}秒后尝试重新连接（第${this.reconnectAttempts}/${this.maxReconnectAttempts}次）`
    );

    this.clearTimer("reconnectTimer");
    this.reconnectTimer = setTimeout(() => {
      console.info(`尝试重新连接WebSocket（第${this.reconnectAttempts}次）`);
      this.connect(false);
    }, delay);
  }

  // 计算重连延迟 - 指数退避策略
  private calculateReconnectDelay(): number {
    // 基础延迟 + 随机值，避免多个客户端同时重连
    const jitter = Math.random() * 1000; // 0-1秒的随机延迟
    const baseDelay = Math.min(
      this.reconnectInterval * Math.pow(1.5, this.reconnectAttempts - 1),
      this.reconnectInterval * 5
    );
    return baseDelay + jitter;
  }

  // 清除指定定时器
  private clearTimer(
    timerName:
      | "detectionTimer"
      | "timeoutTimer"
      | "reconnectTimer"
      | "pingTimer"
      | "connectionTimer"
  ): void {
    if (this[timerName]) {
      clearTimeout(this[timerName] as NodeJS.Timeout);
      this[timerName] = null;
    }
  }

  // 清除所有定时器
  private clearAllTimers(): void {
    this.clearConnectionTimers();
    this.clearTimer("reconnectTimer");
  }

  private clearConnectionTimers(): void {
    this.clearTimer("detectionTimer");
    this.clearTimer("timeoutTimer");
    this.clearTimer("pingTimer");
    this.clearTimer("connectionTimer");
  }

  // 获取当前连接状态
  get isWebSocketConnected(): boolean {
    return this.isConnected;
  }

  // 获取当前连接状态文本
  get connectionStatusText(): string {
    if (this.isConnecting) return "正在连接";
    if (this.isConnected) return "已连接";
    if (this.isReconnecting && this.reconnectAttempts > 0)
      return `重连中（${this.reconnectAttempts}/${this.maxReconnectAttempts}）`;
    return "已断开";
  }

  // 销毁实例
  static destroyInstance(): void {
    if (WebSocketClient.instance) {
      WebSocketClient.instance.close();
      WebSocketClient.instance = null;
    }
  }
}