Live location share - show loading UI for beacons with start timestamp in the future (PSF-1081)

src/components/views/beacon/displayStatus.ts

@@ -25,14 +25,18 @@ export enum BeaconDisplayStatus {
 export const getBeaconDisplayStatus = (
     isLive: boolean,
     latestLocationState?: BeaconLocationState,
-    error?: Error): BeaconDisplayStatus => {
+    error?: Error,
+    waitingToStart?: boolean,
+): BeaconDisplayStatus => {
     if (error) {
         return BeaconDisplayStatus.Error;
     }
+    if (waitingToStart) {
+        return BeaconDisplayStatus.Loading;
+    }
     if (!isLive) {
         return BeaconDisplayStatus.Stopped;
     }
-
     if (!latestLocationState) {
         return BeaconDisplayStatus.Loading;
     }

src/components/views/messages/MBeaconBody.tsx

@@ -23,7 +23,7 @@ import MatrixClientContext from '../../../contexts/MatrixClientContext';
 import { useEventEmitterState } from '../../../hooks/useEventEmitter';
 import { _t } from '../../../languageHandler';
 import Modal from '../../../Modal';
-import { useBeacon } from '../../../utils/beacon';
+import { isBeaconWaitingToStart, useBeacon } from '../../../utils/beacon';
 import { isSelfLocation } from '../../../utils/location';
 import { BeaconDisplayStatus, getBeaconDisplayStatus } from '../beacon/displayStatus';
 import BeaconStatus from '../beacon/BeaconStatus';
@@ -39,6 +39,7 @@ const useBeaconState = (beaconInfoEvent: MatrixEvent): {
     description?: string;
     latestLocationState?: BeaconLocationState;
     isLive?: boolean;
+    waitingToStart?: boolean;
 } => {
     const beacon = useBeacon(beaconInfoEvent);
 
@@ -56,12 +57,19 @@ const useBeaconState = (beaconInfoEvent: MatrixEvent): {
         return {};
     }
 
+    // a beacon's starting timestamp can be in the future
+    // (either from small deviations in system clock times, or on purpose from another client)
+    // a beacon is only live between its start timestamp and expiry
+    // detect when a beacon is waiting to become live
+    // and display a loading state
+    const waitingToStart = !!beacon && isBeaconWaitingToStart(beacon);
     const { description } = beacon.beaconInfo;
 
     return {
         beacon,
         description,
         isLive,
+        waitingToStart,
         latestLocationState,
     };
 };
@@ -84,12 +92,13 @@ const MBeaconBody: React.FC<IBodyProps> = React.forwardRef(({ mxEvent }, ref) =>
         beacon,
         isLive,
         latestLocationState,
+        waitingToStart,
     } = useBeaconState(mxEvent);
     const mapId = useUniqueId(mxEvent.getId());
 
     const matrixClient = useContext(MatrixClientContext);
     const [error, setError] = useState<Error>();
-    const displayStatus = getBeaconDisplayStatus(isLive, latestLocationState, error);
+    const displayStatus = getBeaconDisplayStatus(isLive, latestLocationState, error, waitingToStart);
     const markerRoomMember = isSelfLocation(mxEvent.getContent()) ? mxEvent.sender : undefined;
     const isOwnBeacon = beacon?.beaconInfoOwner === matrixClient.getUserId();
 

src/utils/beacon/duration.ts

@@ -39,3 +39,10 @@ export const sortBeaconsByLatestExpiry = (left: Beacon, right: Beacon): number =
 // aka sort by timestamp descending
 export const sortBeaconsByLatestCreation = (left: Beacon, right: Beacon): number =>
     right.beaconInfo.timestamp - left.beaconInfo.timestamp;
+
+// a beacon's starting timestamp can be in the future
+// (either from small deviations in system clock times, or on purpose from another client)
+// a beacon is only live between its start timestamp and expiry
+// detect when a beacon is waiting to become live
+export const isBeaconWaitingToStart = (beacon: Beacon): boolean =>
+    !beacon.isLive && beacon.beaconInfo.timestamp > Date.now() && getBeaconExpiryTimestamp(beacon) > Date.now();

test/components/views/messages/MBeaconBody-test.tsx

@@ -111,6 +111,19 @@ describe('<MBeaconBody />', () => {
         expect(component.text()).toEqual("Live location ended");
     });
 
+    it('renders loading beacon UI for a beacon that has not started yet', () => {
+        const beaconInfoEvent = makeBeaconInfoEvent(
+            aliceId,
+            roomId,
+            // puts this beacons start timestamp in the future
+            { isLive: true, timestamp: now + 60000, timeout: 500 },
+            '$alice-room1-1',
+        );
+        makeRoomWithStateEvents([beaconInfoEvent], { roomId, mockClient });
+        const component = getComponent({ mxEvent: beaconInfoEvent });
+        expect(component.text()).toEqual("Loading live location...");
+    });
+
     it('does not open maximised map when on click when beacon is stopped', () => {
         const beaconInfoEvent = makeBeaconInfoEvent(aliceId,
             roomId,