import { Injectable } from '@angular/core';
import { Router, CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { AuthService } from './auth.service';
import { Observable, of, throwError } from 'rxjs';
import { catchError } from 'rxjs/operators';
import { HttpErrorResponse } from '@angular/common/http';
import { AuthUserModel } from '../models/auth-user-model';

@Injectable({ providedIn: 'root' })
export class AuthGuard implements CanActivate {


    constructor(
        private router: Router,
        private auth: AuthService
    ) { }

    canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> {
        const result = new Observable<boolean>(observer => {

            this.auth.fetchUser().pipe(
                catchError((err: HttpErrorResponse) => {
                    if(err.status === 401) {
                        observer.next(false);

                        observer.complete();

                        this.router.navigate(['/login']);

                        return of([]);
                    } else{
                        return throwError(err);
                    }

                })
            ).subscribe((user:AuthUserModel) => {
                this.auth.setUser(user);

                observer.next(true);

                observer.complete();
            })
        });

        return result;
    }

}