import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';

import { BehaviorSubject, Observable } from 'rxjs';
import { map } from 'rxjs/operators';

import { User } from '../models/user';
import { BaseService } from './base.service';
import { DateService } from './date.service';


@Injectable({
  providedIn: 'root'
})
export class AuthenticationService extends BaseService {
  private currentUserSubject: BehaviorSubject<User>;
  public currentUser: Observable<User>;

  constructor(private http: HttpClient, private dateService: DateService) {
    super();

    this.currentUserSubject = new BehaviorSubject<User>(JSON.parse(localStorage.getItem('currentUser')));
    this.currentUser = this.currentUserSubject.asObservable();
  }

  public get currentUserValue(): User {
    const tmp = localStorage.getItem('currentUser');
    if (tmp) {
      const storedUser = JSON.parse(tmp);
      if (new Date().getTime() > storedUser.expired) {
        localStorage.removeItem('currentUser');
      }
    }

    return this.currentUserSubject.value;
  }

  login(username: string, password: string) {
    const bodyLogin = {
      login: username,
      password: password
    };

    return this.http.post<any>(`${this.apiUrl}/User/Authenticate`, bodyLogin, {
      headers: this.headers
    })
      .pipe(map(user => {
        // store user details and basic auth credentials in local storage to keep user logged in between page refreshes
        user.authdata = window.btoa(username + ':' + password);
        user.expired = this.dateService.AddDays(new Date(), 1).getTime();

        localStorage.setItem('currentUser', JSON.stringify(user));
        this.currentUserSubject.next(user);
        return user;
      }));
  }

  logout() {
    // remove user from local storage to log user out
    localStorage.removeItem('currentUser');
    this.currentUserSubject.next(null);
  }
}