import {Injectable} from '@angular/core';
import {HttpClient} from '@angular/common/http';
import {BehaviorSubject, from, Observable, of} from "rxjs";
import {COOKIE, User} from "../login/utils/helper.class";
import {catchError, map, timeout} from "rxjs/operators";
import {NavigationEnd, Router} from "@angular/router";
import {EnvironmentSpecificService} from "../utils/properties/environment-specific.service";

@Injectable({
  providedIn: 'root'
})
export class UserManagementService {
  
  private getUserInfoSubject: BehaviorSubject<User> = new BehaviorSubject<User>(null);
  private readonly promise: Promise<User>;
  
  constructor(private http: HttpClient,
              private router: Router,
              private environmentSpecificService: EnvironmentSpecificService) {
    this.promise = new Promise<any>((resolve => {
      this.environmentSpecificService.subscribeEnvironment().subscribe(properties => {
        const token = COOKIE.getCookie('AccessToken');
        if (!token) {
          this.getUserInfoSubject.next(null);
          resolve();
        } else {
          this.http.get<User>(properties.userInfoUrl + token).pipe(map(userInfo => {
            return this.parseUserInfo(userInfo);
          })).pipe(timeout(3000), catchError(() => {
            return of(null);
          })).subscribe(user => {
            this.getUserInfoSubject.next(user);
            resolve();
          });
        }
      });
    }));
    this.router.events.subscribe(event => {
      if (event instanceof NavigationEnd) {
        const token = COOKIE.getCookie('AccessToken');
        if (!token && this.getUserInfoSubject.getValue() !== null) {
          this.getUserInfoSubject.next(null);
        }
      }
    })
  }
  
  public getUserInfo(subject: boolean = true): Observable<User> {
    if(subject) {
      return this.getUserInfoSubject.asObservable();
    } else {
      return from(this.getUserInfoAsync());
    }
  }
  
  private async getUserInfoAsync(): Promise<User> {
    await this.promise;
    return this.getUserInfoSubject.getValue();
  }
  
  private parseUserInfo(info: any) {
    const user: User = new User();
    user.id = (info.sub && info.sub.indexOf('@')) ? info.sub.substring(0, info.sub.indexOf('@')) : info.sub;
    user.firstname = (info.given_name) ? info.given_name : "";
    user.lastname = (info.family_name) ? info.family_name : "";
    user.email = info.email;
    user.fullname = (info.name) ? info.name : "";
    if (user.fullname == "") {
      if (user.firstname != "") {
        user.fullname += user.firstname;
      }
      if (user.lastname != "") {
        user.fullname += user.lastname;
      }
      if (user.fullname == "") { //fullname is still empty set a default
        user.fullname = "Anonymous user";
      }
    }
    if (info.edu_person_entitlements) {
      user.role = info.edu_person_entitlements;
    } else {
      user.role = [];
    }
    user.expirationDate = info.exp;
    return user;
  }
}