import Taro from '@tarojs/taro';
import { getWsUrl } from '@/api/config';
import { get } from '@/api/request';

type MessageHandler = (data: unknown) => void;

class WebSocketManager {
  private connected: boolean = false;
  private handlers: Map<string, Set<MessageHandler>> = new Map();
  private token: string = '';
  private ticket: string = '';
  private reconnectAttempts: number = 0;
  private maxReconnectAttempts: number = 5;
  private reconnectTimer: ReturnType<typeof setTimeout> | null = null;
  private isManualClose: boolean = false;

  async connect(token: string): Promise<void> {
    this.token = token;
    this.isManualClose = false;
    await this.refreshTicketAndConnect();
  }

  private doConnect(): void {
    if (!this.token || !this.ticket) {
      console.warn('[WS] 无 token，无法连接 WebSocket');
      return;
    }

    // 先关闭旧连接
    if (this.connected) {
      try {
        Taro.closeSocket();
      } catch {
        // ignore
      }
      this.connected = false;
    }

    const url = getWsUrl(this.ticket);
    console.log('[WS] 正在连接:', url);

    // 注册全局回调（每次调用会替换上一次的回调）
    Taro.onSocketOpen(() => {
      console.log('[WS] 连接已建立');
      this.connected = true;
      this.reconnectAttempts = 0;
    });

    Taro.onSocketMessage((res) => {
      try {
        const data = JSON.parse(res.data as string);
        const type = (data.type || data.event || 'default') as string;
        const handlers = this.handlers.get(type);
        if (handlers) {
          handlers.forEach((handler) => handler(data));
        }
        // 广播给通配符监听器
        const wildcardHandlers = this.handlers.get('*');
        if (wildcardHandlers) {
          wildcardHandlers.forEach((handler) => handler(data));
        }
      } catch (e) {
        console.error('[WS] 消息解析失败:', e, res.data);
      }
    });

    Taro.onSocketClose(() => {
      console.log('[WS] 连接已关闭');
      this.connected = false;
      if (!this.isManualClose) {
        this.scheduleReconnect();
      }
    });

    Taro.onSocketError((err) => {
      console.error('[WS] 连接错误:', err);
    });

    Taro.connectSocket({
      url,
      fail: (err) => {
        console.error('[WS] 连接失败:', err);
        this.scheduleReconnect();
      },
    });
  }

  private scheduleReconnect(): void {
    if (this.isManualClose) return;
    if (this.reconnectAttempts >= this.maxReconnectAttempts) {
      console.warn('[WS] 达到最大重连次数，停止重连');
      return;
    }

    this.reconnectAttempts++;
    const delay = Math.min(1000 * Math.pow(2, this.reconnectAttempts), 30000);
    console.log(`[WS] ${delay}ms 后第 ${this.reconnectAttempts} 次重连...`);

    if (this.reconnectTimer) {
      clearTimeout(this.reconnectTimer);
    }
    this.reconnectTimer = setTimeout(() => {
      this.refreshTicketAndConnect();
    }, delay);
  }

  private async refreshTicketAndConnect(): Promise<void> {
    if (!this.token) return;
    try {
      const { ticket } = await get<{ ticket: string }>('/ws/ticket');
      this.ticket = ticket;
      this.doConnect();
    } catch (e) {
      console.error('[WS] 获取 ticket 失败:', e);
      this.scheduleReconnect();
    }
  }

  on(type: string, handler: MessageHandler): () => void {
    if (!this.handlers.has(type)) {
      this.handlers.set(type, new Set());
    }
    this.handlers.get(type)!.add(handler);
    return () => {
      this.handlers.get(type)?.delete(handler);
    };
  }

  off(type: string, handler?: MessageHandler): void {
    if (handler) {
      this.handlers.get(type)?.delete(handler);
    } else {
      this.handlers.delete(type);
    }
  }

  send(data: unknown): void {
    if (this.connected) {
      Taro.sendSocketMessage({
        data: typeof data === 'string' ? data : JSON.stringify(data),
        fail: (err) => {
          console.error('[WS] 发送失败:', err);
        },
      });
    } else {
      console.warn('[WS] WebSocket 未连接，无法发送消息');
    }
  }

  close(): void {
    this.isManualClose = true;
    if (this.reconnectTimer) {
      clearTimeout(this.reconnectTimer);
      this.reconnectTimer = null;
    }
    if (this.connected) {
      Taro.closeSocket();
      this.connected = false;
    }
    this.handlers.clear();
    this.reconnectAttempts = 0;
  }

  isConnected(): boolean {
    return this.connected;
  }
}

export const wsManager = new WebSocketManager();