type Handler = (payload: any) => void;

class WsClient {
  private ws: WebSocket | null = null;
  private handlers = new Map<string, Handler[]>();
  private reconnectTimer: ReturnType<typeof setTimeout> | null = null;
  private token: string | null = null;

  connect(token: string) {
    this.token = token;
    const wsBase = import.meta.env.VITE_WS_URL || `${location.protocol === 'https:' ? 'wss' : 'ws'}://${location.host}`;
    this.ws = new WebSocket(`${wsBase}/ws?token=${token}`);

    this.ws.onopen = () => {
      if (this.reconnectTimer) {
        clearTimeout(this.reconnectTimer);
        this.reconnectTimer = null;
      }
      this.emit('connected', null);
    };

    this.ws.onmessage = (event) => {
      try {
        const { type, payload } = JSON.parse(event.data);
        const hs = this.handlers.get(type) || [];
        hs.forEach(h => h(payload));
      } catch {}
    };

    this.ws.onclose = () => {
      this.emit('disconnected', null);
      this.reconnectTimer = setTimeout(() => {
        if (this.token) this.connect(this.token);
      }, 3000);
    };

    this.ws.onerror = () => {
      this.ws?.close();
    };
  }

  on(type: string, handler: Handler) {
    if (!this.handlers.has(type)) this.handlers.set(type, []);
    this.handlers.get(type)!.push(handler);
    return () => {
      const hs = this.handlers.get(type) || [];
      this.handlers.set(type, hs.filter(h => h !== handler));
    };
  }

  private emit(type: string, payload: any) {
    const hs = this.handlers.get(type) || [];
    hs.forEach(h => h(payload));
  }

  send(type: string, payload: any) {
    if (this.ws?.readyState === WebSocket.OPEN) {
      this.ws.send(JSON.stringify({ type, payload }));
    }
  }

  trySend(type: string, payload: any): boolean {
    if (this.ws?.readyState === WebSocket.OPEN) {
      this.ws.send(JSON.stringify({ type, payload }));
      return true;
    }
    return false;
  }

  disconnect() {
    this.token = null;
    if (this.reconnectTimer) clearTimeout(this.reconnectTimer);
    this.ws?.close();
    this.ws = null;
  }
}

export const wsClient = new WsClient();