import { Injectable } from '@angular/core';
import { Router } from '@angular/router';
import { BehaviorSubject, Observable } from 'rxjs';


export interface UserDetails {
  _id: string;
  email: string;
  fullName: string;
  languaje: string;
  keepsession: boolean;
  exp: number;
  iat: number;
}


export interface TokenPayload {
  email: string;
  password: string;
}

@Injectable({
  providedIn: 'root'
})
export class AuthenticationService {

  private token: string;
  private loginStatus: BehaviorSubject<boolean> = new BehaviorSubject<boolean>(null);
  public loginStatus$: Observable<boolean> = this.loginStatus.asObservable();


  constructor(private router: Router) {}

  updateLoginStatus(loginstatus) {
    this.loginStatus.next(loginstatus);
  }

  public saveToken(token: string): void {
    let payload;
    payload = token.split('.')[1];
    payload = window.atob(payload);
    payload = JSON.parse(payload);
    if (payload.keepsession) {
      localStorage.setItem('admin-token', token);
      sessionStorage.removeItem('admin-token');
    } else {
      sessionStorage.setItem('admin-token', token);
      localStorage.removeItem('admin-token');
    }
    this.token = token;
    this.updateLoginStatus(true);
  }

  public getToken(): string {
    if (!this.token) {
      this.token = localStorage.getItem('admin-token');
      if (!this.token) {
        this.token = sessionStorage.getItem('admin-token');
      }
    }
    return this.token;
  }

  public logout(): void {
    this.updateLoginStatus(false);
    this.token = '';
    localStorage.removeItem('admin-token');
    sessionStorage.removeItem('admin-token');
    this.router.navigateByUrl('/main/welcome');
  }

  public getUserDetails(): UserDetails {
    const token = this.getToken();
    let payload;
    if (token) {
      payload = token.split('.')[1];
      payload = window.atob(payload);
      return JSON.parse(payload);
    } else {
      return null;
    }
  }

  public isLoggedIn(): boolean {
    const user = this.getUserDetails();
    if (user) {
       if (user.exp > Date.now() / 1000) {
        this.updateLoginStatus(true);
        return true;
      } else {
        this.updateLoginStatus(false);
        return false;
      }

    } else {
      this.updateLoginStatus(false);
      return false;
    }
  }
}