import { Injectable } from '@angular/core';
import {
  HttpRequest,
  HttpHandler,
  HttpEvent,
  HttpInterceptor,
  HttpErrorResponse
} from '@angular/common/http';
import { Observable, throwError } from 'rxjs';
import { Router } from '@angular/router';
import { MessageService } from './message.service';
import { catchError } from 'rxjs/operators';

@Injectable()
export class ErrorHandlerInterceptor implements HttpInterceptor {

  constructor(private messageService: MessageService, private router: Router) {}

  intercept(request: HttpRequest<unknown>, next: HttpHandler): Observable<HttpEvent<unknown>> {
    return next.handle(request).pipe(
      catchError((errorResponse: HttpErrorResponse) => {
        this.messageService.add(`Intercepted http error: ${JSON.stringify(errorResponse, undefined, 4)}`)
        if (errorResponse.status === 401) {
          this.router.navigate(['login'])
        }
        return throwError(errorResponse)
      })
    )
  }
}