export type WebSocketMessage = {
  type: string;
  payload: Record<string, unknown>;
  timestamp?: number;
};

export type MessageHandler = (message: WebSocketMessage) => void;
export type ConnectionHandler = (connected: boolean) => void;

export class WebSocketService {
  private ws: WebSocket | null = null;
  private messageHandlers = new Set<MessageHandler>();
  private connectionHandlers = new Set<ConnectionHandler>();
  private reconnectTimer: ReturnType<typeof setTimeout> | null = null;
  private url: string;

  constructor() {
    const protocol = window.location.protocol === "https:" ? "wss:" : "ws:";
    this.url = `${protocol}//${window.location.host}/ws`;
  }

  connect(): void {
    if (this.ws?.readyState === WebSocket.OPEN) return;

    this.ws = new WebSocket(this.url);

    this.ws.onopen = () => {
      this.notifyConnection(true);
      if (this.reconnectTimer) {
        clearTimeout(this.reconnectTimer);
        this.reconnectTimer = null;
      }
    };

    this.ws.onmessage = (event) => {
      try {
        const message = JSON.parse(event.data) as WebSocketMessage;
        this.notifyMessage(message);
      } catch (error) {
        console.error("Error parsing WebSocket message:", error);
      }
    };

    this.ws.onerror = (error) => {
      console.error("WebSocket error:", error);
    };

    this.ws.onclose = () => {
      this.notifyConnection(false);
      this.scheduleReconnect();
    };
  }

  disconnect(): void {
    if (this.reconnectTimer) {
      clearTimeout(this.reconnectTimer);
      this.reconnectTimer = null;
    }
    if (this.ws) {
      this.ws.close();
      this.ws = null;
    }
  }

  send(message: WebSocketMessage): void {
    if (this.ws?.readyState !== WebSocket.OPEN) {
      throw new Error("WebSocket not connected");
    }
    this.ws.send(JSON.stringify(message));
  }

  isConnected(): boolean {
    return this.ws?.readyState === WebSocket.OPEN;
  }

  onMessage(handler: MessageHandler): () => void {
    this.messageHandlers.add(handler);
    return () => this.messageHandlers.delete(handler);
  }

  onConnection(handler: ConnectionHandler): () => void {
    this.connectionHandlers.add(handler);
    return () => this.connectionHandlers.delete(handler);
  }

  private notifyMessage(message: WebSocketMessage): void {
    this.messageHandlers.forEach((handler) => handler(message));
  }

  private notifyConnection(connected: boolean): void {
    this.connectionHandlers.forEach((handler) => handler(connected));
  }

  private scheduleReconnect(): void {
    if (!this.reconnectTimer) {
      this.reconnectTimer = setTimeout(() => {
        this.reconnectTimer = null;
        this.connect();
      }, 3000);
    }
  }
}

export const websocketService = new WebSocketService();