fix jwt handler to return proper error codes

frontend/src/app/core/interceptors/jwt.interceptor.ts

@@ -1,11 +1,21 @@
-import { Injectable } from '@angular/core';
-import { HttpInterceptor, HttpRequest, HttpHandler, HttpEvent } from '@angular/common/http';
-import { Observable } from 'rxjs';
+import { Injectable, inject } from '@angular/core';
+import {
+  HttpInterceptor,
+  HttpRequest,
+  HttpHandler,
+  HttpEvent,
+  HttpErrorResponse,
+} from '@angular/common/http';
+import { BehaviorSubject, Observable, catchError, filter, switchMap, take, throwError } from 'rxjs';
 import { AuthService } from '../services/auth.service';
+import { Router } from '@angular/router';
 
 @Injectable()
 export class JwtInterceptor implements HttpInterceptor {
-  constructor(private authService: AuthService) {}
+  private authService = inject(AuthService);
+  private router = inject(Router);
+  private isRefreshing = false;
+  private refreshTokenSubject = new BehaviorSubject<string | null>(null);
 
   intercept(req: HttpRequest<unknown>, next: HttpHandler): Observable<HttpEvent<unknown>> {
     const token = this.authService.getAccessToken();
@@ -14,6 +24,65 @@ export class JwtInterceptor implements HttpInterceptor {
         setHeaders: { Authorization: `Bearer ${token}` },
       });
     }
-    return next.handle(req);
+
+    return next.handle(req).pipe(
+      catchError((error) => {
+        if (
+          error instanceof HttpErrorResponse &&
+          error.status === 401 &&
+          !req.url.includes('/api/auth/refresh')
+        ) {
+          return this.handle401Error(req, next);
+        }
+        return throwError(() => error);
+      }),
+    );
+  }
+
+  private handle401Error(
+    req: HttpRequest<unknown>,
+    next: HttpHandler,
+  ): Observable<HttpEvent<unknown>> {
+    if (!this.isRefreshing) {
+      this.isRefreshing = true;
+      this.refreshTokenSubject.next(null);
+
+      const refreshToken = this.authService.getRefreshToken();
+      if (!refreshToken) {
+        this.authService.clearSessionForLogout();
+        this.router.navigate(['/login']);
+        return throwError(() => new Error('No refresh token available'));
+      }
+
+      return this.authService.refreshToken(refreshToken).pipe(
+        switchMap((res) => {
+          this.isRefreshing = false;
+          this.refreshTokenSubject.next(res.accessToken);
+          return next.handle(
+            req.clone({
+              setHeaders: { Authorization: `Bearer ${res.accessToken}` },
+            }),
+          );
+        }),
+        catchError((err) => {
+          this.isRefreshing = false;
+          this.authService.clearSessionForLogout();
+          this.router.navigate(['/login']);
+          return throwError(() => err);
+        }),
+      );
+    } else {
+      return this.refreshTokenSubject.pipe(
+        filter((token): token is string => token !== null),
+        take(1),
+        switchMap((token) =>
+          next.handle(
+            req.clone({
+              setHeaders: { Authorization: `Bearer ${token}` },
+            }),
+          ),
+        ),
+      );
+    }
   }
 }