1 files changed, 51 insertions, 0 deletions
diff --git a/FrontEnd/src/app/services/timeline.ts b/FrontEnd/src/app/services/timeline.ts
index a24ec8eb..c49ba654 100644
--- a/FrontEnd/src/app/services/timeline.ts
+++ b/FrontEnd/src/app/services/timeline.ts
@@ -1,5 +1,11 @@
 import { TimelineVisibility } from "@/http/timeline";
 import XRegExp from "xregexp";
+import { Observable } from "rxjs";
+import { HubConnection, HubConnectionBuilder } from "@microsoft/signalr";
+
+import { UiLogicError } from "@/common";
+
+import { token$ } from "@/http/common";
 
 const timelineNameReg = XRegExp("^[-_\\p{L}]*$", "u");
 
@@ -15,3 +21,48 @@ export const timelineVisibilityTooltipTranslationMap: Record<
   Register: "timeline.visibilityTooltip.register",
   Private: "timeline.visibilityTooltip.private",
 };
+
+function generateTimelineHubUrl(token: string | null): string {
+  return `/api/hub/timeline${token == null ? "" : "?token=" + token}`;
+}
+
+function createTimelineHubConnection(token: string | null): HubConnection {
+  return new HubConnectionBuilder()
+    .withUrl(generateTimelineHubUrl(token))
+    .withAutomaticReconnect()
+    .build();
+}
+
+let timelineHubConnection: HubConnection | null = null;
+
+token$.subscribe((token) => {
+  if (timelineHubConnection != null) {
+    void timelineHubConnection.stop();
+  }
+  timelineHubConnection = createTimelineHubConnection(token);
+  void timelineHubConnection.start();
+});
+
+export function getTimelinePostUpdate(
+  timelineName: string
+): Observable<string> {
+  return new Observable((subscriber) => {
+    if (timelineHubConnection == null)
+      throw new UiLogicError("Connection is null.");
+
+    const connection = timelineHubConnection;
+
+    const handler = (tn: string): void => {
+      if (timelineName === tn) {
+        subscriber.next(tn);
+      }
+    };
+    connection.on("OnTimelinePostChanged", handler);
+    void connection.invoke("SubscribeTimelinePostChange", timelineName);
+
+    return () => {
+      void connection.invoke("UnsubscribeTimelinePostChange", timelineName);
+      connection.off("OnTimelinePostChanged", handler);
+    };
+  });
+}