From 78399a6b1efd761cf39c0f9451be070210cec8f1 Mon Sep 17 00:00:00 2001
From: limcaaarl <carljovi22@gmail.com>
Date: Tue, 12 Nov 2024 23:14:07 +0800
Subject: [PATCH] Bug fix for #77 - Users will now be warned if their tokens
 are about to expire - Users will be logged out upon token expiration

---
 .../src/_services/authentication.service.ts   | 35 +++++++++++++++++++
 frontend/src/app/app.component.html           |  1 +
 frontend/src/app/app.component.ts             | 16 ++++++---
 3 files changed, 48 insertions(+), 4 deletions(-)

diff --git a/frontend/src/_services/authentication.service.ts b/frontend/src/_services/authentication.service.ts
index 303303b39e..a3e4894f38 100644
--- a/frontend/src/_services/authentication.service.ts
+++ b/frontend/src/_services/authentication.service.ts
@@ -7,6 +7,7 @@ import { map, switchMap } from 'rxjs/operators';
 import { UServRes } from '../_models/user.service.model';
 import { User } from '../_models/user.model';
 import { ApiService } from './api.service';
+import { ToastService } from './toast.service';
 
 @Injectable({ providedIn: 'root' })
 export class AuthenticationService extends ApiService {
@@ -18,6 +19,7 @@ export class AuthenticationService extends ApiService {
     constructor(
         private router: Router,
         private http: HttpClient,
+        private toastService: ToastService,
     ) {
         super();
         const userData = localStorage.getItem('user');
@@ -53,6 +55,8 @@ export class AuthenticationService extends ApiService {
                     }
                     localStorage.setItem('user', JSON.stringify(user));
                     this.userSubject.next(user);
+                    this.startTokenExpiryCheck();
+
                     return user;
                 }),
             );
@@ -99,4 +103,35 @@ export class AuthenticationService extends ApiService {
             }),
         );
     }
+    public startTokenExpiryCheck(): void {
+        const tokenExpirationTime = this.getTokenExpiration();
+
+        if (!tokenExpirationTime) {
+            this.logout();
+            return;
+        }
+
+        const oneMinute = 60 * 1000;
+        const checkInterval = oneMinute;
+
+        setInterval(() => {
+            const now = Date.now();
+            const timeLeft = tokenExpirationTime - now;
+
+            if (timeLeft <= 0) {
+                this.toastService.showToast('Your session has expired. Please log in again.');
+                this.logout();
+            } else if (timeLeft < 5 * oneMinute) {
+                this.toastService.showToast('Your session will expire in less than 5 minutes. Please log in again');
+            }
+        }, checkInterval);
+    }
+
+    private getTokenExpiration() {
+        const user = this.userValue;
+        if (!user || !user.accessToken) return null;
+
+        const tokenPayload = JSON.parse(atob(user.accessToken.split('.')[1]));
+        return tokenPayload.exp ? tokenPayload.exp * 1000 : null;
+    }
 }
diff --git a/frontend/src/app/app.component.html b/frontend/src/app/app.component.html
index a20a5cb8af..d702e4580e 100644
--- a/frontend/src/app/app.component.html
+++ b/frontend/src/app/app.component.html
@@ -1,4 +1,5 @@
 <main>
     <app-navigation-bar />
+    <p-toast></p-toast>
     <router-outlet />
 </main>
diff --git a/frontend/src/app/app.component.ts b/frontend/src/app/app.component.ts
index d0722c2b03..0e29dabf67 100644
--- a/frontend/src/app/app.component.ts
+++ b/frontend/src/app/app.component.ts
@@ -1,16 +1,24 @@
-import { Component } from '@angular/core';
+import { Component, OnInit } from '@angular/core';
 import { RouterOutlet } from '@angular/router';
 import { ButtonModule } from 'primeng/button';
 import { PasswordModule } from 'primeng/password';
+import { ToastModule } from 'primeng/toast';
 import { NavigationBarComponent } from './navigation-bar/navigation-bar.component';
-
+import { AuthenticationService } from '../_services/authentication.service';
+import { MessageService } from 'primeng/api';
 @Component({
     selector: 'app-root',
     standalone: true,
-    imports: [NavigationBarComponent, RouterOutlet, ButtonModule, PasswordModule],
+    imports: [NavigationBarComponent, RouterOutlet, ButtonModule, PasswordModule, ToastModule],
+    providers: [MessageService],
     templateUrl: './app.component.html',
     styleUrl: './app.component.css',
 })
-export class AppComponent {
+export class AppComponent implements OnInit {
     title = 'frontend';
+
+    constructor(private authService: AuthenticationService) {}
+    ngOnInit() {
+        this.authService.startTokenExpiryCheck();
+    }
 }