import { Injectable } from '@angular/core';
import {AuthUser} from './user.service';
import { Subject } from 'rxjs/Subject';
import { Router } from '@angular/router';

@Injectable()
export class AuthService {

  public UserLoggedInSubject:Subject<AuthUser>;
  public logoutTime = 15;//15 minutes
  public logoutDialogShown:boolean;

  constructor(private router:Router) {
    this.UserLoggedInSubject = new Subject<AuthUser>();
    this.logoutDialogShown = false;
  }

  public login(authUser:AuthUser):AuthUser{
    this.storeUser(authUser);
    this.UserLoggedInSubject.next(authUser);
    this.logoutDialogShown = false;
    return this.getStoredUser();
  }

  public logout(redirectToLogin=true){
    if(typeof window.localStorage.user != 'undefined' && window.localStorage.user != null){
      window.localStorage.user = null;
      this.UserLoggedInSubject.next(null);
      if(this.logoutDialogShown == false){
        alert("You have been logged out");
        if(redirectToLogin ){
          this.router.navigateByUrl("/login");
        }
        this.logoutDialogShown = true;
      }

    }
  }

  private storeUser(authUser:AuthUser){
    window.localStorage.user = JSON.stringify(authUser);
  }

  public getStoredUser():AuthUser{
    if(typeof window.localStorage.user != 'undefined' && window.localStorage.user != null && window.localStorage.user != 'null'){
      let parsedUser    =   JSON.parse(window.localStorage.user);
      let tokenLifeSpan =   this.addMinutes(new Date(parsedUser.token_creation_time*1000),this.logoutTime);
      let currentTime   =   new Date();
      if(currentTime < tokenLifeSpan){
        return parsedUser;
      }
    }
    this.logout();
    return null;
  }

  private addMinutes(date:Date, minutes:number) :Date{
    return new Date(date.getTime() + minutes*60000);
  }

}