open-learning-exchange/planet

import { Injectable } from '@angular/core';
import { UserService } from './user.service';
import { Observable, of } from 'rxjs';
import { switchMap, map } from 'rxjs/operators';
import { Router, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { PouchAuthService } from './database/pouch-auth.service';
import { StateService } from './state.service';

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

  constructor(
    private userService: UserService,
    private router: Router,
    private pouchAuthService: PouchAuthService,
    private stateService: StateService
  ) { }

  private getSession$() {
    return this.pouchAuthService.getSessionInfo();
  }

  private checkUser(url: any): Observable<boolean> {
    return this.getSession$().pipe(
      switchMap((sessionInfo) => {
        if (sessionInfo.userCtx.name) {
          // If user already matches one on the user service, do not make additional call to CouchDB
          if (sessionInfo.userCtx.name === this.userService.get().name) {
            return of(true);
          }
          this.stateService.requestBaseData();
          return this.userService.setUserAndShelf(sessionInfo.userCtx);
        }
        this.userService.unset();
        const returnUrl = url === '/' ? null : url;
        this.router.navigate([ '/login' ], { queryParams: { returnUrl }, replaceUrl: true });
        return of(false);
      }),
      map(isLoggedIn => isLoggedIn)
    );
  }

  // For main app (which requires login).  Uses canActivateChild to check on every route
  // change if session has expired
  canActivateChild(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> {
    return this.checkUser(state.url);
  }

  // For login route will redirect to main app if there is an active session
  canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> {
    return this.getSession$().pipe(
      map((sessionInfo) => {
        if (sessionInfo.userCtx.name) {
          this.router.navigate([ '' ]);
          return false;
        }
        return true;
      })
    );
  }

}