Invert overtime (#1715)

* refactor: invert offset calculation

* chore: update tests

* chore: flip offset in UI

* fix seconds display on group target duration

* update comment

* fix rebase

apps/client/src/common/utils/offset.ts

@@ -21,5 +21,6 @@ export function getOffsetText(offset: MaybeNumber): string {
 export function getOffsetState(offset: MaybeNumber): 'over' | 'under' | 'muted' | null {
   if (offset === null) return 'muted';
   if (offset === 0) return null;
-  return offset < 0 ? 'over' : 'under';
+  // a positive value means that we are in over time aka behind schedule
+  return offset > 0 ? 'over' : 'under';
 }

apps/client/src/features/overview/composite/TimeElements.tsx

@@ -167,9 +167,8 @@ export function OffsetOverview() {
   const { offset, playback } = useRuntimePlaybackOverview();
 
   const isPlaying = isPlaybackActive(playback);
-  const correctedOffset = offset * -1;
   const offsetState = getOffsetState(isPlaying ? offset : null);
-  const offsetText = getOffsetText(isPlaying ? correctedOffset : null);
+  const offsetText = getOffsetText(isPlaying ? offset : null);
 
   return <OverUnder state={offsetState} value={offsetText} testId='offset' />;
 }

apps/client/src/features/rundown/entry-editor/GroupEditor.tsx

@@ -50,8 +50,8 @@ export default function GroupEditor({ group }: GroupEditorProps) {
   );
 
   const isEditor = window.location.pathname.includes('editor');
-  const planOffset = typeof group.targetDuration !== 'number' ? null : group.duration - group.targetDuration;
-  const planOffsetLabel = planOffset !== null ? getOffsetState(planOffset * -1) : null;
+  const planOffset = group.targetDuration === null ? null : group.duration - group.targetDuration;
+  const planOffsetLabel = planOffset !== null ? getOffsetState(planOffset) : null;
 
   return (
     <div className={style.content}>

apps/client/src/features/rundown/rundown-group/RundownGroup.tsx

@@ -10,6 +10,7 @@ import {
 import { useSortable } from '@dnd-kit/sortable';
 import { CSS } from '@dnd-kit/utilities';
 import { EntryId, OntimeGroup } from 'ontime-types';
+import { MILLIS_PER_MINUTE } from 'ontime-utils';
 
 import IconButton from '../../../common/components/buttons/IconButton';
 import { useContextMenu } from '../../../common/hooks/useContextMenu';
@@ -102,8 +103,11 @@ export default function RundownGroup({ data, hasCursor, collapsed, onCollapse }:
     if (offset === 0) {
       return [null, 'under'];
     }
-
-    return [offset < 0 ? `-${formatDuration(offset * -1)}` : `+${formatDuration(offset)}`, getOffsetState(offset * -1)];
+    const absOffset = Math.abs(offset);
+    return [
+      `${offset < 0 ? '-' : '+'}${formatDuration(absOffset, absOffset > 2 * MILLIS_PER_MINUTE)}`,
+      getOffsetState(offset),
+    ];
   })();
 
   const dragStyle = {

apps/server/src/services/__tests__/timerUtils.test.ts

@@ -742,7 +742,7 @@ describe('getRuntimeOffset()', () => {
     } as RuntimeState;
 
     const { offsetAbs } = getRuntimeOffset(state);
-    expect(offsetAbs).toBe(-50);
+    expect(offsetAbs).toBe(50);
   });
 
   it('added time subtracts time offset (positive offset)', () => {
@@ -766,7 +766,7 @@ describe('getRuntimeOffset()', () => {
     } as RuntimeState;
 
     const { offsetAbs } = getRuntimeOffset(state);
-    expect(offsetAbs).toBe(-60);
+    expect(offsetAbs).toBe(60);
   });
 
   it('considers running overtime (negative offset)', () => {
@@ -791,7 +791,7 @@ describe('getRuntimeOffset()', () => {
     } as RuntimeState;
 
     const { offsetAbs } = getRuntimeOffset(state);
-    expect(offsetAbs).toBe(-10);
+    expect(offsetAbs).toBe(10);
   });
 
   it('paused time is delayed time (negative offset)', () => {
@@ -817,7 +817,7 @@ describe('getRuntimeOffset()', () => {
     } as RuntimeState;
 
     const { offsetAbs } = getRuntimeOffset(state);
-    expect(offsetAbs).toBe(-25);
+    expect(offsetAbs).toBe(25);
   });
 
   it('offset doesnt exist if we havent started', () => {
@@ -857,46 +857,6 @@ describe('getRuntimeOffset()', () => {
     expect(offsetAbs).toBe(0);
   });
 
-  it('handles loaded event', () => {
-    const state = {
-      clock: 79521653,
-      eventNow: {
-        id: '835242',
-        timeStart: 81000000,
-        timeEnd: 84600000,
-        duration: 3600000,
-        timeStrategy: 'lock-duration',
-        linkStart: false,
-        endAction: 'none',
-        timerType: 'count-down',
-        delay: 0,
-      },
-      runtime: {
-        selectedEventIndex: 1,
-        numEvents: 2,
-        offsetAbs: -81000000,
-        plannedStart: 77400000,
-        plannedEnd: 84600000,
-        actualStart: 79443403,
-        expectedEnd: null,
-      },
-      timer: {
-        addedTime: 0,
-        current: 3600000,
-        duration: 3600000,
-        elapsed: null,
-        expectedFinish: null,
-        playback: 'armed',
-        secondaryTimer: null,
-        startedAt: null,
-      },
-      _timer: { pausedAt: null },
-    } as RuntimeState;
-
-    const { offsetAbs } = getRuntimeOffset(state);
-    expect(offsetAbs).toBe(81000000 - 79521653); // clock - timestart
-  });
-
   it('with time-to-end, offsets dont exist if we are not in overtime', () => {
     const state = {
       clock: 80000000, // 22:13:20
@@ -996,7 +956,7 @@ describe('getRuntimeOffset()', () => {
     } as RuntimeState;
 
     const { offsetAbs } = getRuntimeOffset(state);
-    expect(offsetAbs).toBe(-400000); // <--- offset is always the overtime
+    expect(offsetAbs).toBe(400000); // <--- offset is always the overtime
   });
 
   it('handles time-to-end started after the end time', () => {
@@ -1038,8 +998,8 @@ describe('getRuntimeOffset()', () => {
     const updateCurrent = getCurrent(state);
     state.timer.current = updateCurrent;
     const { offsetAbs } = getRuntimeOffset(state);
-    expect(millisToString(offsetAbs)).toBe('-00:16:40');
-    expect(offsetAbs).toBe(81000000 - 82000000); // <-- planned end - now
+    expect(millisToString(offsetAbs)).toBe('00:16:40');
+    expect(offsetAbs).toBe(82000000 - 81000000); // <-- now - planned end
   });
 });
 
@@ -1089,7 +1049,7 @@ describe('getoffsetRel()', () => {
     } as RuntimeState;
 
     const { offsetAbs, offsetRel } = getRuntimeOffset(state);
-    expect(offsetAbs).toBe(-50);
+    expect(offsetAbs).toBe(50);
     expect(offsetRel).toBe(0);
   });
   it('relative offset is 0 when starting before the planed time', () => {
@@ -1113,7 +1073,7 @@ describe('getoffsetRel()', () => {
     } as RuntimeState;
 
     const { offsetAbs, offsetRel } = getRuntimeOffset(state);
-    expect(offsetAbs).toBe(50);
+    expect(offsetAbs).toBe(-50);
     expect(offsetRel).toBe(0);
   });
 });

apps/server/src/services/timerUtils.ts

@@ -109,57 +109,44 @@ export function skippedOutOfEvent(state: RuntimeState, previousTime: number, ski
 
 /**
  * Calculates difference between the runtime and the schedule of an event
- * Positive offset is time ahead
- * Negative offset is time delayed
+ * Positive offset is over time / behind schedule
+ * Negative offset is under time / ahead of schedule
  */
 export function getRuntimeOffset(state: RuntimeState): { offsetAbs: number; offsetRel: number } {
+  const { eventNow, clock } = state;
+  const { addedTime, current, startedAt } = state.timer;
   // nothing to calculate if there are no loaded events or if we havent started
-  if (state.eventNow === null || state.runtime.actualStart === null) {
+  if (eventNow === null || startedAt === null) {
     return { offsetAbs: 0, offsetRel: 0 };
   }
 
-  const { clock } = state;
-  const { countToEnd, timeStart } = state.eventNow;
-  const { addedTime, current, startedAt } = state.timer;
-  const { actualStart, plannedStart } = state.runtime;
+  const { countToEnd, timeStart } = eventNow;
+  const { plannedStart, actualStart } = state.runtime;
 
   // eslint-disable-next-line no-unused-labels -- dev code path
   DEV: {
     // we know current exists as long as eventNow exists
     if (current === null) throw new Error('timerUtils.getRuntimeOffset: state.timer.current must be set');
     if (plannedStart === null) throw new Error('timerUtils.getRuntimeOffset: state.runtime.plannedStart must be set');
+    if (actualStart === null) throw new Error('timerUtils.getRuntimeOffset: state.runtime.actualStart must be set');
   }
 
-  // if we havent started, but the timer is armed
-  // the offset is the difference to the schedule
-  if (startedAt === null) {
-    return { offsetAbs: timeStart - clock, offsetRel: 0 };
-  }
+  // difference between planned event start and actual event start (will be positive if we stared behind )
+  const eventStartOffset = startedAt - timeStart;
 
-  const overtime = Math.min(current, 0);
-  // in time-to-end, offset is overtime
+  // how long has the event been running over (is a negative number when in over timer so inverted before adding to offset)
+  const overtime = Math.abs(Math.min(current, 0));
 
-  const startOffset = timeStart - startedAt;
+  // time the playback was paused, the different from now to when we paused is added to the offset TODO: brakes when crossing midnight
   const pausedTime = state._timer.pausedAt === null ? 0 : clock - state._timer.pausedAt;
 
-  // startOffset - difference between scheduled start and actual start
-  // addedTime - time added by user (negative offset)
-  // pausedTime - time the playback was paused (negative offset)
-  // overtime - how long the timer has been over-running (negative offset)
-  const offset = startOffset - addedTime - pausedTime + overtime;
+  const offsetAbs = eventStartOffset + overtime + pausedTime + addedTime;
 
-  // offset between planned rundown start and actual rundown start
-  const rundownStartOffset = actualStart - plannedStart;
+  // the relative offset i the same as the absolute offset but adjusted relative to the actual start time
+  const offsetRel = offsetAbs + plannedStart - actualStart;
 
-  // offset offset relative to the actual rundown start
-  const offsetRel = offset + rundownStartOffset;
-
-  // in time-to-end, offset is overtime
-  if (countToEnd) {
-    return { offsetAbs: overtime, offsetRel };
-  }
-
-  return { offsetAbs: offset, offsetRel };
+  // in case of count to end, the absolute offset is just the overtime
+  return countToEnd ? { offsetAbs: overtime, offsetRel } : { offsetAbs, offsetRel };
 }
 
 /**

apps/server/src/stores/__tests__/runtimeState.test.ts

@@ -67,17 +67,20 @@ beforeAll(() => {
 });
 
 describe('mutation on runtimeState', () => {
+  beforeEach(() => {
+    vi.useFakeTimers();
+    vi.setSystemTime('jan 1 00:01');
+  });
   afterEach(() => {
     vi.clearAllMocks();
+    vi.useRealTimers();
   });
 
   describe('playback operations', async () => {
     it('refuses if nothing is loaded', async () => {
       // force update
-      vi.useFakeTimers();
       await initRundown(makeRundown({}), {});
       vi.runAllTimers();
-      vi.useRealTimers();
 
       let success = start(mockState);
       expect(success).toBe(false);
@@ -93,10 +96,8 @@ describe('mutation on runtimeState', () => {
         order: [mockEvent.id, 'event2'],
       });
       // force update
-      vi.useFakeTimers();
       await initRundown(mockRundown, {});
       vi.runAllTimers();
-      vi.useRealTimers();
 
       const { metadata, rundown } = rundownCache.get();
       load(mockEvent, rundown, metadata);
@@ -108,6 +109,7 @@ describe('mutation on runtimeState', () => {
       expect(newState.groupNow).toBeNull();
 
       // 2. Start event
+      vi.setSystemTime('jan 1 00:02');
       let success = start();
       newState = getState();
       expect(success).toBe(true);
@@ -117,6 +119,7 @@ describe('mutation on runtimeState', () => {
       expect(newState.runtime.actualStart).toBe(newState.clock);
 
       // 3. Pause event
+      vi.setSystemTime('jan 1 00:03');
       success = pause();
       newState = getState();
       expect(success).toBe(true);
@@ -131,6 +134,7 @@ describe('mutation on runtimeState', () => {
       expect(success).toBe(false);
 
       // 4. Restart event
+      vi.setSystemTime('jan 1 00:04');
       success = start();
       newState = getState();
       expect(success).toBe(true);
@@ -150,6 +154,7 @@ describe('mutation on runtimeState', () => {
       expect(newState._timer.pausedAt).toBeNull();
 
       // 5. Stop event
+      vi.setSystemTime('jan 1 00:05');
       success = stop();
       newState = getState();
       expect(success).toBe(true);
@@ -163,80 +168,81 @@ describe('mutation on runtimeState', () => {
       });
       expect(newState.runtime.actualStart).toBeNull();
     });
+  });
 
-    test('runtime offset', async () => {
-      const entries = {
-        event1: { ...mockEvent, id: 'event1', timeStart: 0, timeEnd: 1000, duration: 1000, parent: null },
-        event2: { ...mockEvent, id: 'event2', timeStart: 1000, timeEnd: 1500, duration: 500, parent: null },
-      };
-      const mockRundown = makeRundown({ entries, order: ['event1', 'event2'] });
+  test('runtime offset', async () => {
+    const entries = {
+      event1: { ...mockEvent, id: 'event1', timeStart: 0, timeEnd: 1000, duration: 1000, parent: null },
+      event2: { ...mockEvent, id: 'event2', timeStart: 1000, timeEnd: 1500, duration: 500, parent: null },
+    };
+    const mockRundown = makeRundown({ entries, order: ['event1', 'event2'] });
 
-      // force update
-      vi.useFakeTimers();
-      await initRundown(mockRundown, {});
-      vi.runAllTimers();
-      vi.useRealTimers();
+    // force update
+    await initRundown(mockRundown, {});
+    vi.runAllTimers();
 
-      const { metadata, rundown } = rundownCache.get();
+    const { metadata, rundown } = rundownCache.get();
 
-      // 1. Load event
-      load(entries.event1, rundown, metadata);
-      let newState = getState();
-      expect(newState.runtime.actualStart).toBeNull();
-      expect(newState.runtime.plannedStart).toBe(0);
-      expect(newState.runtime.plannedEnd).toBe(1500);
-      expect(newState.groupNow).toBeNull();
-      expect(newState.runtime.offsetAbs).toBe(0);
+    // 1. Load event
+    vi.setSystemTime('jan 1 00:09');
+    load(entries.event1, rundown, metadata);
+    let newState = getState();
+    expect(newState.runtime.actualStart).toBeNull();
+    expect(newState.runtime.plannedStart).toBe(0);
+    expect(newState.runtime.plannedEnd).toBe(1500);
+    expect(newState.groupNow).toBeNull();
+    expect(newState.runtime.offsetAbs).toBe(0);
 
-      // 2. Start event
-      start();
-      newState = getState();
-      const firstStart = newState.clock;
-      if (newState.runtime.offsetAbs === null) {
-        throw new Error('Value cannot be null at this stage');
-      }
+    // 2. Start event
+    vi.setSystemTime('jan 1 00:10');
+    start();
+    newState = getState();
+    const firstStart = newState.clock;
+    if (newState.runtime.offsetAbs === null) {
+      throw new Error('Value cannot be null at this stage');
+    }
 
-      expect(newState.runtime.actualStart).toBe(newState.clock);
-      expect(newState.runtime.offsetAbs).toBe(entries.event1.timeStart - newState.clock);
-      expect(newState.runtime.expectedEnd).toBe(entries.event2.timeEnd - newState.runtime.offsetAbs);
+    expect(newState.runtime.actualStart).toBe(newState.clock);
+    expect(newState.runtime.offsetAbs).toBe(newState.clock - entries.event1.timeStart);
+    expect(newState.runtime.expectedEnd).toBe(entries.event2.timeEnd + newState.runtime.offsetAbs);
 
-      // 3. Next event
-      load(entries.event2, rundown, metadata);
-      start();
+    // 3. Next event
+    vi.setSystemTime('jan 1 00:12');
+    load(entries.event2, rundown, metadata);
+    start();
 
-      newState = getState();
-      if (newState.runtime.actualStart === null || newState.runtime.offsetAbs === null) {
-        throw new Error('Value cannot be null at this stage');
-      }
+    newState = getState();
+    if (newState.runtime.actualStart === null || newState.runtime.offsetAbs === null) {
+      throw new Error('Value cannot be null at this stage');
+    }
 
-      // there is a case where the calculation time overflows the millisecond which makes
-      // tests fail
-      const forgivingActualStart = Math.abs(newState.runtime.actualStart - firstStart);
-      expect(forgivingActualStart).toBeLessThanOrEqual(1);
-      // we are over-under, the difference between the schedule and the actual start
-      const delayBefore = entries.event2.timeStart - newState.clock;
-      expect(newState.runtime.offsetAbs).toBe(delayBefore);
-      // finish is the difference between the runtime and the schedule
-      expect(newState.runtime.expectedEnd).toBe(entries.event2.timeEnd - newState.runtime.offsetAbs);
-      expect(newState.groupNow).toBeNull();
+    // there is a case where the calculation time overflows the millisecond which makes
+    // tests fail
+    const forgivingActualStart = Math.abs(newState.runtime.actualStart - firstStart);
+    expect(forgivingActualStart).toBeLessThanOrEqual(1);
+    // we are over-under, the difference between the schedule and the actual start
+    const delayBefore = newState.clock - entries.event2.timeStart;
+    expect(newState.runtime.offsetAbs).toBe(delayBefore);
+    // finish is the difference between the runtime and the schedule
+    expect(newState.runtime.expectedEnd).toBe(newState.runtime.offsetAbs + entries.event2.timeEnd);
+    expect(newState.groupNow).toBeNull();
 
-      // 4. Add time
-      addTime(10);
-      newState = getState();
-      if (newState.runtime.offsetAbs === null) {
-        throw new Error('Value cannot be null at this stage');
-      }
+    // 4. Add time
+    addTime(10);
+    newState = getState();
+    if (newState.runtime.offsetAbs === null) {
+      throw new Error('Value cannot be null at this stage');
+    }
 
-      expect(newState.runtime.offsetAbs).toBe(delayBefore - 10);
-      expect(newState.runtime.expectedEnd).toBe(entries.event2.timeEnd - newState.runtime.offsetAbs);
+    expect(newState.runtime.offsetAbs).toBe(delayBefore + 10);
+    expect(newState.runtime.expectedEnd).toBe(entries.event2.timeEnd + newState.runtime.offsetAbs);
 
-      // 5. Stop event
-      stop();
-      newState = getState();
-      expect(newState.runtime.actualStart).toBeNull();
-      expect(newState.runtime.offsetAbs).toBe(0);
-      expect(newState.runtime.expectedEnd).toBeNull();
-    });
+    // 5. Stop event
+    stop();
+    newState = getState();
+    expect(newState.runtime.actualStart).toBeNull();
+    expect(newState.runtime.offsetAbs).toBe(0);
+    expect(newState.runtime.expectedEnd).toBeNull();
   });
 });
 
@@ -326,7 +332,7 @@ describe('roll mode', () => {
       start();
       const result = roll(rundown, metadata);
       expect(result).toStrictEqual({ eventId: '1', didStart: false });
-      expect(getState().runtime.offsetAbs).toBe(1000);
+      expect(getState().runtime.offsetAbs).toBe(-1000);
     });
   });
 
@@ -353,18 +359,18 @@ describe('roll mode', () => {
       const currentOffset = getState().runtime.offsetAbs;
       let result = roll(rundown, metadata, getState().runtime.offsetAbs);
       expect(result).toStrictEqual({ eventId: '1', didStart: false });
-      // the current offset should be maintain by roll mode whn taking over from play
+      // the current offset should be maintain by roll mode when taking over from play
       expect(getState().runtime.offsetAbs).toBe(currentOffset);
 
       vi.setSystemTime('jan 1 00:00:01');
       result = roll(rundown, metadata, getState().runtime.offsetAbs);
       expect(result).toStrictEqual({ eventId: '2', didStart: true });
-      expect(getState().runtime.offsetAbs).toBe(1000);
+      expect(getState().runtime.offsetAbs).toBe(-1000);
 
       vi.setSystemTime('jan 1 00:00:02');
       result = roll(rundown, metadata, getState().runtime.offsetAbs);
       expect(result).toStrictEqual({ eventId: '3', didStart: true });
-      expect(getState().runtime.offsetAbs).toBe(1000);
+      expect(getState().runtime.offsetAbs).toBe(-1000);
 
       vi.useRealTimers();
     });

apps/server/src/stores/runtimeState.ts

@@ -314,7 +314,7 @@ export function updateLoaded(event?: PlayableEvent): string | undefined {
 
     // handle edge cases with roll
     if (runtimeState.timer.playback === Playback.Roll) {
-      const offsetClock = runtimeState.clock + runtimeState.runtime.offsetAbs;
+      const offsetClock = runtimeState.clock - runtimeState.runtime.offsetAbs;
       // if waiting to roll, we update the targets and potentially start the timer
       if (runtimeState._timer.secondaryTarget !== null) {
         if (runtimeState.eventNow.timeStart < offsetClock && offsetClock < runtimeState.eventNow.timeEnd) {
@@ -391,7 +391,6 @@ export function start(state: RuntimeState = runtimeState): boolean {
   state.timer.expectedFinish = getExpectedFinish(state);
   state.timer.elapsed = 0;
 
-  // update runtime delays: over - under
   if (state.runtime.actualStart === null) {
     state.runtime.actualStart = state.clock;
   }
@@ -521,7 +520,6 @@ export function update(): UpdateResult {
   const { offsetAbs, offsetRel } = getRuntimeOffset(runtimeState);
   runtimeState.runtime.offsetAbs = offsetAbs;
   runtimeState.runtime.offsetRel = offsetRel;
-  // runtimeState.runtime.expectedEnd = getExpectedEnd(runtimeState);
 
   const finishedNow =
     Boolean(runtimeState._timer.forceFinish) ||
@@ -596,7 +594,7 @@ export function roll(
     runtimeState.timer.expectedFinish = normalisedEndTime;
 
     //account for offset
-    const offsetClock = runtimeState.clock + runtimeState.runtime.offsetAbs;
+    const offsetClock = runtimeState.clock - runtimeState.runtime.offsetAbs;
 
     // state catch up
     runtimeState.timer.duration = calculateDuration(runtimeState.eventNow.timeStart, normalisedEndTime);
@@ -635,7 +633,7 @@ export function roll(
 
   //account for offset but we only keep it if passed to us
   runtimeState.runtime.offsetAbs = offset;
-  const offsetClock = runtimeState.clock + runtimeState.runtime.offsetAbs;
+  const offsetClock = runtimeState.clock - runtimeState.runtime.offsetAbs;
 
   const { index, isPending } = loadRoll(rundown, metadata, offsetClock);
 

packages/types/src/definitions/runtime/Runtime.type.ts

@@ -8,7 +8,7 @@ export enum OffsetMode {
 export type Runtime = {
   selectedEventIndex: MaybeNumber;
   numEvents: number;
-  offsetAbs: number;
+  offsetAbs: number; // a positive value means that we are in over time aka behind schedule
   offsetRel: number;
   plannedStart: MaybeNumber;
   actualStart: MaybeNumber;

packages/utils/src/date-utils/getExpectedStart.test.ts

@@ -33,7 +33,7 @@ describe('getExpectedStart()', () => {
       const testState = {
         currentDay: 0,
         totalGap: 0,
-        offset: -20,
+        offset: 20,
         offsetMode: OffsetMode.Absolute,
         actualStart: null,
         plannedStart: null,
@@ -52,7 +52,7 @@ describe('getExpectedStart()', () => {
       const testState = {
         currentDay: 0,
         totalGap: 0,
-        offset: 10,
+        offset: -10,
         offsetMode: OffsetMode.Absolute,
         actualStart: null,
         plannedStart: null,
@@ -71,7 +71,7 @@ describe('getExpectedStart()', () => {
       const testState = {
         currentDay: 0,
         totalGap: 20,
-        offset: -20,
+        offset: 20,
         offsetMode: OffsetMode.Absolute,
         actualStart: null,
         plannedStart: null,
@@ -90,7 +90,7 @@ describe('getExpectedStart()', () => {
       const testState = {
         currentDay: 0,
         totalGap: 10,
-        offset: -20,
+        offset: 20,
         offsetMode: OffsetMode.Absolute,
         actualStart: 0,
         plannedStart: 0,
@@ -219,12 +219,12 @@ describe('getExpectedStart()', () => {
       expect(getExpectedStart(testEvent, { ...testState, isLinkedToLoaded: true })).toBe(120);
       expect(getExpectedStart(testEvent, { ...testState, isLinkedToLoaded: false })).toBe(120);
 
-      testState.offset = 5; // remove 5 with addtime - we are ahead of time
+      testState.offset = -5; // remove 5 with addtime - we are ahead of time
 
       expect(getExpectedStart(testEvent, { ...testState, isLinkedToLoaded: true })).toBe(115);
-      expect(getExpectedStart(testEvent, { ...testState, isLinkedToLoaded: false })).toBe(120); // unlocked evets will stay on schedule
+      expect(getExpectedStart(testEvent, { ...testState, isLinkedToLoaded: false })).toBe(120); // unlinked events will stay on schedule
 
-      testState.offset = -5; // add 5 with addtime - we are behind
+      testState.offset = +5; // add 5 with addtime - we are behind
 
       expect(getExpectedStart(testEvent, { ...testState, isLinkedToLoaded: true })).toBe(125);
       expect(getExpectedStart(testEvent, { ...testState, isLinkedToLoaded: false })).toBe(125);

packages/utils/src/date-utils/getExpectedStart.ts

@@ -43,14 +43,14 @@ export function getExpectedStart(
 
   const scheduledStartTime = normalisedTimeStart + relativeStartOffset;
 
-  const offsetStartTime = scheduledStartTime - offset;
+  const offsetStartTime = scheduledStartTime + offset;
 
   if (isLinkedToLoaded) {
     //if we are directly linked back to the loaded event we just follow the offset
     return offsetStartTime;
   }
 
-  const gapsCanCompensateForOffset = totalGap + offset >= 0;
+  const gapsCanCompensateForOffset = totalGap > offset;
   if (gapsCanCompensateForOffset) {
     // if we are ahead of schedule or the gap can compensate for the amount we are behind then expect to start at the scheduled time
     return scheduledStartTime;