feat: add Keycloak authentication integration and guard

src/app/service/auth.service.ts

@@ -0,0 +1,42 @@
+import { Injectable } from '@angular/core';
+import {
+  ActivatedRouteSnapshot,
+  Router,
+  RouterStateSnapshot
+} from '@angular/router';
+import { KeycloakAuthGuard, KeycloakService } from 'keycloak-angular';
+
+@Injectable({
+  providedIn: 'root'
+})
+export class AuthGuard extends KeycloakAuthGuard {
+  constructor(
+    protected override readonly router: Router,
+    protected readonly keycloak: KeycloakService
+  ) {
+    super(router, keycloak);
+  }
+
+  public async isAccessAllowed(
+    route: ActivatedRouteSnapshot,
+    state: RouterStateSnapshot
+  ) {
+    // Force the user to log in if currently unauthenticated.
+    if (!this.authenticated) {
+      await this.keycloak.login({
+        redirectUri: window.location.origin + state.url
+      });
+    }
+
+    // Get the roles required from the route.
+    const requiredRoles = route.data['roles'];
+
+    // Allow the user to proceed if no additional roles are required to access the route.
+    if (!Array.isArray(requiredRoles) || requiredRoles.length === 0) {
+      return true;
+    }
+
+    // Allow the user to proceed if all the required roles are present.
+    return requiredRoles.every((role) => this.roles.includes(role));
+  }
+}