From 74fc682dbf1f6ac67653dc61d0483d615352362e Mon Sep 17 00:00:00 2001
From: Jason Kulatunga <jason@thesparktree.com>
Date: Fri, 8 Sep 2023 14:10:37 -0700
Subject: [PATCH] renamed sse endpoint to events. Using the technology name in
 the API isnt a good idea.

---
 backend/pkg/web/server.go                     |  2 +-
 .../app/components/toast/toast.component.ts   | 30 ++++++++++++++++++-
 .../src/app/services/fasten-api.service.ts    | 24 +++++++++++++++
 3 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/backend/pkg/web/server.go b/backend/pkg/web/server.go
index c41523abf..a4d8b5005 100644
--- a/backend/pkg/web/server.go
+++ b/backend/pkg/web/server.go
@@ -79,7 +79,7 @@ func (ae *AppEngine) Setup() (*gin.RouterGroup, *gin.Engine) {
 				secure.POST("/query", handler.QueryResourceFhir)
 
 				//server-side-events handler
-				secure.GET("/sse/stream", middleware.SSEHeaderMiddleware(), middleware.SSEEventBusServerMiddleware(), handler.SSEStream)
+				secure.GET("/events/stream", middleware.SSEHeaderMiddleware(), middleware.SSEEventBusServerMiddleware(), handler.SSEStream)
 			}
 
 			if ae.Config.GetBool("web.allow_unsafe_endpoints") {
diff --git a/frontend/src/app/components/toast/toast.component.ts b/frontend/src/app/components/toast/toast.component.ts
index a4d4301d8..69885e131 100644
--- a/frontend/src/app/components/toast/toast.component.ts
+++ b/frontend/src/app/components/toast/toast.component.ts
@@ -1,5 +1,9 @@
 import {Component, OnInit, TemplateRef} from '@angular/core';
 import {ToastService} from '../../services/toast.service';
+import {AuthService} from '../../services/auth.service';
+import {FastenApiService} from '../../services/fasten-api.service';
+import {Subscription} from 'rxjs';
+import {NavigationEnd, Router} from '@angular/router';
 
 @Component({
   selector: 'app-toast',
@@ -7,9 +11,33 @@ import {ToastService} from '../../services/toast.service';
   styleUrls: ['./toast.component.scss']
 })
 export class ToastComponent implements OnInit {
+  routerSubscription: Subscription | undefined;
 
-  constructor(public toastService: ToastService) {}
+  constructor(
+    public router: Router,
+    public toastService: ToastService,
+    public authService: AuthService,
+    public fastenApiService: FastenApiService,
+  ) {}
 
   ngOnInit(): void {
+
+  }
+  ngAfterViewInit() {
+    //TODO: this is a bit kludgey.
+    // Ideally we want consistently listen to events, but only when the user is authenticated.
+    this.routerSubscription = this.router.events.subscribe((event) => {
+      if (event instanceof NavigationEnd) {
+        if(!event.url.startsWith("/auth") && this.authService.IsAuthenticated()){
+          console.log("user is authenticated, listening for notifications")
+          //user is authenticated, lets start listening for notifications
+          this.routerSubscription?.unsubscribe()
+          this.fastenApiService.listenEventBus().subscribe((event)=>{
+            console.log("eventbus event:", event)
+            //TODO: start toasts.
+          })
+        }
+      }
+    });
   }
 }
diff --git a/frontend/src/app/services/fasten-api.service.ts b/frontend/src/app/services/fasten-api.service.ts
index d318ef5f5..4aeec2f90 100644
--- a/frontend/src/app/services/fasten-api.service.ts
+++ b/frontend/src/app/services/fasten-api.service.ts
@@ -22,6 +22,7 @@ import * as fhirpath from 'fhirpath';
 import _ from 'lodash';
 import {DashboardConfig} from '../models/widget/dashboard-config';
 import {DashboardWidgetQuery} from '../models/widget/dashboard-widget-query';
+import { fetchEventSource } from '@microsoft/fetch-event-source';
 
 @Injectable({
   providedIn: 'root'
@@ -54,6 +55,29 @@ export class FastenApiService {
   SECURE ENDPOINTS
   */
 
+  listenEventBus(): Observable<any> {
+    let eventStreamUrl = `${GetEndpointAbsolutePath(globalThis.location, environment.fasten_api_endpoint_base)}/secure/events/stream`
+
+    return new Observable(observer => {
+      fetchEventSource(eventStreamUrl, {
+        method: 'GET',
+        headers: {
+          'Content-Type': 'application/json',
+          'Authorization': `Bearer ${this.authService.GetAuthToken()}`
+        },
+        onmessage(ev) {
+          observer.next(ev.data);
+        },
+        onerror(event) {
+          observer.error(event)
+        },
+      }).then(
+        () => observer.complete(),
+        error => observer.error(error)
+      )
+    });
+  }
+
   getDashboards(): Observable<DashboardConfig[]> {
     return this._httpClient.get<any>(`${GetEndpointAbsolutePath(globalThis.location, environment.fasten_api_endpoint_base)}/secure/dashboards`, )
       .pipe(