import { Injectable } from '@angular/core';
import { Observable, Subject, BehaviorSubject } from 'rxjs';
import { webSocket, WebSocketSubject } from 'rxjs/webSocket';
import { catchError, retryWhen, tap, delay } from 'rxjs/operators';

interface WebSocketMessage {
type: string;
payload: any;
}

interface WebSocketError {
type: string;
error: any;
}

@Injectable({
providedIn: 'root'
})
export class MessageLiveDataSourceService {
  private socket$: WebSocketSubject<WebSocketMessage>;
  private messageSubject$: Subject<WebSocketMessage>;
  private connectionStatus$: BehaviorSubject<boolean>;
  private reconnectAttempts = 0;
  private readonly maxReconnectAttempts = 5;

  constructor() {
    this.messageSubject$ = new Subject<WebSocketMessage>();
    this.connectionStatus$ = new BehaviorSubject<boolean>(false);
  }

  public connect(url: string) {
    this.socket$ = webSocket<WebSocketMessage>(url);

    this.socket$.pipe(
      tap({
        error: () => {
          this.connectionStatus$.next(false);
        }
      }),
      retryWhen(errors => errors.pipe(
        tap(() => {
          this.reconnectAttempts++;
          if (this.reconnectAttempts >= this.maxReconnectAttempts) {
            throw new Error('Max reconnect attempts reached');
          }
        }),
        delay(1000)
      ))
    ).subscribe(
      (message) => {
        this.messageSubject$.next(message);
        this.connectionStatus$.next(true);
        this.reconnectAttempts = 0;
      },
      (err) => {
        console.error('WebSocket connection error:', err);
      },
      () => {
        console.log('WebSocket connection closed');
        this.connectionStatus$.next(false);
      }
    );
  }

    public sendMessage(message: WebSocketMessage): Observable<void> {
        return new Observable<void>(observer => {
        this.socket$.next(message);
        observer.next();
        observer.complete();
      }).pipe(
        catchError(err => {
          console.error('Send message error:', err);
          return new Observable<never>(observer => {
            observer.error({ type: 'SEND_ERROR', error: err });
          });
        })
      );
    }

  public get messages$(): Observable<WebSocketMessage> {
    return this.messageSubject$.asObservable();
  }

  public get connectionStatus(): Observable<boolean> {
    return this.connectionStatus$.asObservable();
  }
}