fix: count-to-end events break link chain

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

@@ -4,6 +4,7 @@ import {
   MILLIS_PER_MINUTE,
   MILLIS_PER_SECOND,
   formatFromMillis,
+  getExpectedEnd,
   getExpectedStart,
 } from 'ontime-utils';
 
@@ -172,23 +173,28 @@ export function getExpectedTimesFromExtendedEvent(
 ) {
   if (event === null) return { expectedStart: 0, timeToStart: 0, expectedEnd: 0, plannedEnd: 0 };
 
+  const expectedStartState = {
+    totalGap: event.totalGap,
+    isLinkedToLoaded: event.isLinkedToLoaded,
+    ...state,
+  };
+
   const expectedStart = getExpectedStart(
     { timeStart: event.timeStart, delay: event.delay, dayOffset: event.dayOffset },
-    {
-      totalGap: event.totalGap,
-      isLinkedToLoaded: event.isLinkedToLoaded,
-      ...state,
-    },
+    expectedStartState,
   );
 
-  const plannedEnd = event.timeStart + event.duration + event.delay;
+  // count to end events are fixed to the scheduled end and ignore delays
+  const delayToAdd = event.countToEnd ? 0 : event.delay;
+  const plannedEnd = event.timeStart + event.duration + delayToAdd;
+
+  // we let timeToStart go negative to allow the UI to show due timers
+  const timeToStart = expectedStart - state.clock;
 
   return {
     expectedStart,
-    timeToStart: expectedStart - state.clock,
-    expectedEnd: event.countToEnd
-      ? Math.max(expectedStart + event.duration, plannedEnd)
-      : expectedStart + event.duration,
+    timeToStart,
+    expectedEnd: getExpectedEnd(event, expectedStartState),
     plannedEnd,
   };
 }

apps/client/src/views/countdown/CountdownSubscriptions.tsx

@@ -151,9 +151,8 @@ type ScheduleTimeProps = {
   showExpected: boolean;
 };
 //TODO: consider relative mode
-export function ScheduleTime(props: ScheduleTimeProps) {
-  const { event, showExpected } = props;
-  const { timeStart, duration, delay, expectedStart, countToEnd } = event;
+export function ScheduleTime({ event, showExpected }: ScheduleTimeProps) {
+  const { timeStart, duration, delay, expectedStart, expectedEnd, countToEnd } = event;
 
   const plannedStart = timeStart + delay + event.dayOffset * dayInMs;
 
@@ -163,8 +162,14 @@ export function ScheduleTime(props: ScheduleTimeProps) {
   const plannedStateClass = isExpectedValueShow ? 'sub__schedule--strike' : delay !== 0 ? 'sub__schedule--delayed' : '';
 
   const expectedStateClass = `sub__schedule--${getOffsetState(expectedStart - plannedStart)}`;
-  const plannedEnd = plannedStart + duration + delay;
-  const expectedEnd = countToEnd ? Math.max(expectedStart + duration, plannedEnd) : expectedStart + duration;
+
+  // count to end events are fixed to the scheduled end and ignore delays
+  const plannedEnd = (() => {
+    if (countToEnd) {
+      return timeStart + event.dayOffset * dayInMs + duration;
+    }
+    return plannedStart + duration;
+  })();
   const expectedEndClass = `sub__schedule--${getOffsetState(expectedEnd - plannedEnd)}`;
 
   return (

apps/client/src/views/countdown/SingleEventCountdown.tsx

@@ -1,5 +1,4 @@
 import { MaybeNumber, OntimeEvent } from 'ontime-types';
-import { getExpectedStart } from 'ontime-utils';
 import { IoPencil } from 'react-icons/io5';
 
 import Button from '../../common/components/buttons/Button';
@@ -11,7 +10,7 @@ import { cx } from '../../common/utils/styleUtils';
 import SuperscriptTime from '../common/superscript-time/SuperscriptTime';
 import { getPropertyValue } from '../common/viewUtils';
 import { useCountdownOptions } from './countdown.options';
-import { CountdownTarget, useSubscriptionDisplayData } from './countdown.utils';
+import { CountdownTarget, extendEventData, useSubscriptionDisplayData } from './countdown.utils';
 import { ScheduleTime } from './CountdownSubscriptions';
 
 import './SingleEventCountdown.scss';
@@ -27,19 +26,15 @@ export default function SingleEventCountdown({ subscribedEvent, goToEditMode }:
   const { data: reportData } = useReport();
 
   const { offset, currentDay, actualStart, plannedStart, mode } = useExpectedStartData();
-  const { totalGap, isLinkedToLoaded } = subscribedEvent;
-  const expectedStart = getExpectedStart(subscribedEvent, {
+  const countdownEvent = extendEventData(
+    subscribedEvent,
     currentDay,
-    totalGap,
     actualStart,
     plannedStart,
-    isLinkedToLoaded,
     offset,
     mode,
-  });
-
-  const { endedAt } = reportData[subscribedEvent.reportId ?? subscribedEvent.id] ?? { endedAt: null };
-  const countdownEvent = { ...subscribedEvent, expectedStart, endedAt };
+    reportData,
+  );
   const titleTmp = getPropertyValue(subscribedEvent, mainSource ?? 'title');
   const title = titleTmp?.length ? titleTmp : ' '; // insert utf-8 empty space to avoid the line collapsing;
   // while a group is live, surface the running event's title as the secondary line

apps/client/src/views/countdown/countdown.utils.ts

@@ -12,7 +12,7 @@ import {
   isOntimeGroup,
   isPlayableEvent,
 } from 'ontime-types';
-import { MILLIS_PER_MINUTE, getExpectedStart, millisToString, removeLeadingZero } from 'ontime-utils';
+import { MILLIS_PER_MINUTE, getExpectedEnd, getExpectedStart, millisToString, removeLeadingZero } from 'ontime-utils';
 
 import { useCountdownSocket } from '../../common/hooks/useSocket';
 import { ExtendedEntry } from '../../common/utils/rundownMetadata';
@@ -197,7 +197,11 @@ export type CountdownTarget = ExtendedEntry<OntimeEvent> & {
   liveEntry?: ExtendedEntry<OntimeEvent> | null; // the running child while a group is live
 };
 
-export type CountdownEvent = CountdownTarget & { expectedStart: number; endedAt: MaybeNumber };
+export type CountdownEvent = CountdownTarget & {
+  expectedStart: number;
+  expectedEnd: number;
+  endedAt: MaybeNumber;
+};
 
 /**
  * Resolves a subscription (event or group) into an event-shaped countdown target.
@@ -262,7 +266,7 @@ export function extendEventData(
   reportData: OntimeReport,
 ): CountdownEvent {
   const { totalGap, isLinkedToLoaded } = event;
-  const expectedStart = getExpectedStart(event, {
+  const expectedStartState = {
     currentDay,
     totalGap,
     actualStart,
@@ -270,7 +274,9 @@ export function extendEventData(
     isLinkedToLoaded,
     offset,
     mode,
-  });
+  };
+  const expectedStart = getExpectedStart(event, expectedStartState);
+  const expectedEnd = getExpectedEnd(event, expectedStartState);
   const { endedAt } = reportData[event.reportId ?? event.id] ?? { endedAt: null };
-  return { ...event, expectedStart, endedAt };
+  return { ...event, expectedStart, expectedEnd, endedAt };
 }

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

@@ -7,11 +7,21 @@ import { initRundown } from '../../api-data/rundown/rundown.service.js';
 import { loadRoll } from '../rollUtils.js';
 
 vi.mock('../../classes/data-provider/DataProvider.js', () => {
+  let automation = {
+    enabledAutomations: false,
+    enabledOscIn: false,
+    oscPortIn: 8888,
+    triggers: [],
+    automations: {},
+  };
+
   return {
     getDataProvider: vi.fn().mockImplementation(() => {
       return {
+        getAutomation: vi.fn().mockImplementation(() => automation),
         setCustomFields: vi.fn().mockImplementation((newData) => newData),
         setRundown: vi.fn().mockImplementation((newData) => newData),
+        setAutomation: vi.fn().mockImplementation((newData) => (automation = newData)),
       };
     }),
   };

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

@@ -225,7 +225,7 @@ describe('getExpectedFinish()', () => {
     expect(calculatedFinish).toBe(10);
   });
   describe('on timers of type time-to-end', () => {
-    it('finish time is as schedule + added time', () => {
+    it('finish time is the fixed end, ignoring added time', () => {
       const state = {
         eventNow: {
           timeEnd: 30,
@@ -242,8 +242,31 @@ describe('getExpectedFinish()', () => {
         },
       } as RuntimeState;
 
+      // the end is anchored: added time surfaces as offset, it does not move the finish
       const calculatedFinish = getExpectedFinish(state);
-      expect(calculatedFinish).toBe(40);
+      expect(calculatedFinish).toBe(30);
+    });
+
+    it('finish time is the fixed end, ignoring pauses', () => {
+      const state = {
+        eventNow: {
+          timeEnd: 30,
+          countToEnd: true,
+        },
+        clock: 25,
+        timer: {
+          addedTime: 0,
+          duration: dayInMs,
+          startedAt: 10,
+        },
+        _timer: {
+          pausedAt: 20, // paused 5 ago - wall clock keeps approaching the fixed end
+          hasFinished: false,
+        },
+      } as RuntimeState;
+
+      const calculatedFinish = getExpectedFinish(state);
+      expect(calculatedFinish).toBe(30);
     });
     it('handles events that finish the day after', () => {
       const state = {
@@ -451,7 +474,7 @@ describe('getCurrent()', () => {
       expect(current).toBe(70);
     });
 
-    it('current time is the time to end + added time', () => {
+    it('current time is the time to end, ignoring added time', () => {
       const state = {
         eventNow: {
           timeEnd: 100,
@@ -472,8 +495,9 @@ describe('getCurrent()', () => {
         },
       } as RuntimeState;
 
+      // counts to the fixed end; added time surfaces as offset, not extra countdown
       const current = getCurrent(state);
-      expect(current).toBe(77);
+      expect(current).toBe(70);
     });
 
     it('handles events that finish the day after', () => {
@@ -1073,7 +1097,7 @@ describe('getRuntimeOffset()', () => {
     expect(absolute).toBe(0);
   });
 
-  it('with time-to-end, offset is the overtime', () => {
+  it('with time-to-end, offset combines overtime and added time', () => {
     const state = {
       clock: 82000000, // 22:46:40
       eventNow: {
@@ -1126,7 +1150,45 @@ describe('getRuntimeOffset()', () => {
     } as RuntimeState;
 
     const { absolute } = getRuntimeOffset(state);
-    expect(absolute).toBe(400000); // <--- offset is always the overtime
+    // overtime (400000) plus the operator's added time (-200000)
+    expect(absolute).toBe(200000);
+  });
+
+  it('with time-to-end, added time surfaces as offset', () => {
+    const state = {
+      clock: 80000000, // 22:13:20 - before the scheduled end, not in overtime
+      eventNow: {
+        id: 'd6a2ce',
+        timeStart: 77400000, // 21:30:00
+        timeEnd: 81000000, // 22:30:00
+        duration: 3600000, // 01:00:00
+        timeStrategy: TimeStrategy.LockEnd,
+        countToEnd: true,
+        dayOffset: 0,
+        delay: 0,
+      },
+      rundown: {
+        plannedStart: 77400000, // 21:30:00
+        plannedEnd: 81000000, // 22:30:00
+        actualStart: 78000000, // 21:40:00
+        currentDay: 0,
+      },
+      offset: {
+        absolute: 0,
+      },
+      timer: {
+        addedTime: 300000, // operator added 5 minutes
+        current: 1000000, // still counting down, no overtime
+        duration: 3600000,
+        startedAt: 78000000,
+      },
+      _startDayOffset: 0,
+      _timer: { pausedAt: null },
+    } as RuntimeState;
+
+    // the end is anchored, so the added 5 minutes shows up purely as offset
+    const { absolute } = getRuntimeOffset(state);
+    expect(absolute).toBe(300000);
   });
 
   it('handles time-to-end started after the end time', () => {

apps/server/src/services/timerUtils.ts

@@ -41,7 +41,9 @@ export function getExpectedFinish(state: RuntimeState): MaybeNumber {
   const pausedTime = pausedAt != null ? clock - pausedAt : 0;
 
   if (countToEnd) {
-    return timeEnd + addedTime + pausedTime;
+    // count to end events are anchored to their fixed end: added time and pauses
+    // do not move the end, they surface as offset instead (see getRuntimeOffset)
+    return timeEnd;
   }
 
   // handle events that finish the day after
@@ -74,9 +76,10 @@ export function getCurrent(state: RuntimeState): number {
   const { clock } = state;
 
   if (countToEnd) {
+    // count to end runs to its fixed end, so added time does not stretch the countdown
     const isEventOverMidnight = timeStart > timeEnd;
     const correctDay = isEventOverMidnight ? dayInMs : 0;
-    return correctDay - clock + timeEnd + addedTime;
+    return correctDay - clock + timeEnd;
   }
 
   if (startedAt === null) {
@@ -180,13 +183,14 @@ export function getRuntimeOffset(state: RuntimeState): { absolute: number; relat
   const pausedTime = state._timer.pausedAt === null ? 0 : clock - state._timer.pausedAt;
 
   // absolute offset is difference between schedule and playback time
-  const absolute = eventStartOffset + overtime + pausedTime + addedTime;
+  // count to end is anchored to its fixed end, so it absorbs the late start (eventStartOffset)
+  // and the pause (already reflected in overtime); added time surfaces here as offset
+  const absolute = countToEnd ? overtime + addedTime : eventStartOffset + overtime + pausedTime + addedTime;
 
   // the relative offset is the same as the absolute but adjusted relative to the actual start time
   const relative = absolute + plannedStart - actualStart - _startDayOffset * dayInMs;
 
-  // in case of count to end, the absolute offset is just the overtime
-  return countToEnd ? { absolute: overtime, relative } : { absolute, relative };
+  return { absolute, relative };
 }
 
 /**

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

@@ -56,18 +56,21 @@ const mockState = {
 } as RuntimeState;
 
 vi.mock('../../classes/data-provider/DataProvider.js', () => {
+  let automation = {
+    enabledAutomations: false,
+    enabledOscIn: false,
+    oscPortIn: 8888,
+    triggers: [],
+    automations: {},
+  };
+
   return {
     getDataProvider: vi.fn().mockImplementation(() => {
       return {
+        getAutomation: vi.fn().mockImplementation(() => automation),
         setCustomFields: vi.fn().mockImplementation((newData) => newData),
         setRundown: vi.fn().mockImplementation((newData) => newData),
-        getAutomation: vi.fn().mockReturnValue({
-          enabledAutomations: false,
-          enabledOscIn: false,
-          oscPortIn: 0,
-          triggers: [],
-          automations: {},
-        }),
+        setAutomation: vi.fn().mockImplementation((newData) => (automation = newData)),
       };
     }),
   };
@@ -325,6 +328,121 @@ describe('mutation on runtimeState', () => {
     expect(newState.offset.expectedRundownEnd).toBeNull();
   });
 
+  test('a countToEnd last event absorbs overtime into its fixed rundown end', async () => {
+    const entries = {
+      event1: {
+        ...mockEvent,
+        id: 'event1',
+        timeStart: 10 * MILLIS_PER_HOUR,
+        timeEnd: 11 * MILLIS_PER_HOUR,
+        duration: MILLIS_PER_HOUR,
+        parent: null,
+      },
+      event2: {
+        ...mockEvent,
+        id: 'event2',
+        timeStart: 11 * MILLIS_PER_HOUR,
+        timeEnd: 12 * MILLIS_PER_HOUR,
+        duration: MILLIS_PER_HOUR,
+        countToEnd: true,
+        linkStart: true,
+        parent: null,
+      },
+    };
+    const mockRundown = makeRundown({ entries, order: ['event1', 'event2'] });
+
+    await initRundown(mockRundown, {});
+    vi.runAllTimers();
+
+    const { metadata, rundown } = rundownCache.get();
+
+    // start event1 five minutes behind schedule
+    vi.setSystemTime('jan 1 10:05');
+    load(entries.event1, rundown, metadata);
+    start();
+    update();
+
+    const newState = getState();
+    expect(newState.offset.absolute).toBe(5 * MILLIS_PER_MINUTE);
+
+    // without countToEnd the rundown would end at 12h + 5min, but the countToEnd
+    // event absorbs the overtime so the rundown is still expected to end at 12h
+    expect(newState.offset.expectedRundownEnd).toBe(12 * MILLIS_PER_HOUR);
+  });
+
+  test('adding time to a running countToEnd event surfaces as offset and end remains fixed', async () => {
+    const entries = {
+      event1: {
+        ...mockEvent,
+        id: 'event1',
+        timeStart: 10 * MILLIS_PER_HOUR,
+        timeEnd: 12 * MILLIS_PER_HOUR,
+        duration: 2 * MILLIS_PER_HOUR,
+        countToEnd: true,
+        parent: null,
+      },
+    };
+    const mockRundown = makeRundown({ entries, order: ['event1'] });
+
+    await initRundown(mockRundown, {});
+    vi.runAllTimers();
+
+    const { metadata, rundown } = rundownCache.get();
+
+    // start on time
+    vi.setSystemTime('jan 1 10:00');
+    load(entries.event1, rundown, metadata);
+    start();
+    update();
+
+    let state = getState();
+    expect(state.offset.absolute).toBe(0);
+    expect(state.timer.expectedFinish).toBe(12 * MILLIS_PER_HOUR);
+    expect(state.offset.expectedRundownEnd).toBe(12 * MILLIS_PER_HOUR);
+
+    // operator adds 5 minutes
+    addTime(5 * MILLIS_PER_MINUTE);
+
+    state = getState();
+    // the end cant move, so the added time is added to the offset
+    expect(state.offset.absolute).toBe(5 * MILLIS_PER_MINUTE);
+    expect(state.timer.expectedFinish).toBe(12 * MILLIS_PER_HOUR);
+    expect(state.offset.expectedRundownEnd).toBe(12 * MILLIS_PER_HOUR);
+  });
+
+  test('subtracting more than the remaining time does not finish a countToEnd event', async () => {
+    const entries = {
+      event1: {
+        ...mockEvent,
+        id: 'event1',
+        timeStart: 10 * MILLIS_PER_HOUR,
+        timeEnd: 12 * MILLIS_PER_HOUR,
+        duration: 2 * MILLIS_PER_HOUR,
+        countToEnd: true,
+        parent: null,
+      },
+    };
+    const mockRundown = makeRundown({ entries, order: ['event1'] });
+
+    await initRundown(mockRundown, {});
+    vi.runAllTimers();
+
+    const { metadata, rundown } = rundownCache.get();
+
+    vi.setSystemTime('jan 1 10:00');
+    load(entries.event1, rundown, metadata);
+    start();
+    update();
+
+    // removing longer than the remaining time cannot finish the event since the end is fixed
+    addTime(-3 * MILLIS_PER_HOUR);
+    update();
+
+    const state = getState();
+    expect(state.timer.playback).toBe(Playback.Play);
+    expect(state.timer.expectedFinish).toBe(12 * MILLIS_PER_HOUR);
+  });
+
   test('resume restores currentDay from restore point', async () => {
     clearState();
     const mockRundown = makeRundown({
@@ -1036,4 +1154,32 @@ describe('loadGroupFlagAndEnd()', () => {
       eventNow: rundown.entries[0],
     });
   });
+
+  test('a countToEnd event breaks the link chain for the events that follow it', () => {
+    // chain: A (loaded) -> B (countToEnd, flagged) -> C (linked, last event)
+    // the chain stays intact up to and including B, but breaks for C since it follows a countToEnd event
+    const rundown = makeRundown({
+      entries: {
+        A: makeOntimeEvent({ id: 'A', parent: null, linkStart: false, countToEnd: false, gap: 0 }),
+        B: makeOntimeEvent({ id: 'B', parent: null, linkStart: true, countToEnd: true, gap: 0, flag: true }),
+        C: makeOntimeEvent({ id: 'C', parent: null, linkStart: true, countToEnd: false, gap: 0 }),
+      },
+      order: ['A', 'B', 'C'],
+    });
+
+    const state = {
+      groupNow: null,
+      eventNow: rundown.entries.A,
+      rundown: { actualGroupStart: null },
+    } as RuntimeState;
+
+    const metadata = { playableEventOrder: ['A', 'B', 'C'], flags: ['B'] } as RundownMetadata;
+
+    loadGroupFlagAndEnd(rundown, metadata, 0, state);
+
+    // the flag (B) is still part of the chain
+    expect(state._flag).toMatchObject({ event: rundown.entries.B, isLinkedToLoaded: true });
+    // the rundown end (C) follows the countToEnd event, so the chain is broken
+    expect(state._end).toMatchObject({ event: rundown.entries.C, isLinkedToLoaded: false });
+  });
 });

apps/server/src/stores/runtimeState.ts

@@ -23,6 +23,7 @@ import {
   calculateDuration,
   checkIsNow,
   dayInMs,
+  getExpectedEnd,
   getExpectedStart,
   getLastEventNormal,
   isPlaybackActive,
@@ -43,6 +44,7 @@ import {
   hasCrossedMidnight,
 } from '../services/timerUtils.js';
 import { timerConfig } from '../setup/config.js';
+import { shouldCrashDev } from '../utils/development.js';
 
 type ExpectedMetadata = {
   event: OntimeEvent;
@@ -509,23 +511,31 @@ export function addTime(amount: number) {
     }
   }
 
-  // handle edge cases
-  // !!! we need to handle side effects before updating the state
-  const willGoNegative = amount < 0 && Math.abs(amount) > runtimeState.timer.current;
-
-  if (willGoNegative && !runtimeState._timer.hasFinished) {
-    // set finished time so side effects are triggered
-    runtimeState._timer.forceFinish = timeCore.timeOfDayNow();
+  if (runtimeState.eventNow?.countToEnd) {
+    // count to end is anchored to its fixed end: added time cannot move the end or finish
+    // the event early, it only surfaces as offset. `current` is derived from the wall clock
+    // by the update loop, so we must not bump it here.
+    runtimeState.timer.addedTime += amount;
   } else {
-    const willGoPositive = runtimeState.timer.current < 0 && runtimeState.timer.current + amount > 0;
-    if (willGoPositive) {
-      runtimeState._timer.hasFinished = false;
+    // handle edge cases
+    // !!! we need to handle side effects before updating the state
+    const willGoNegative = amount < 0 && Math.abs(amount) > runtimeState.timer.current;
+
+    if (willGoNegative && !runtimeState._timer.hasFinished) {
+      // set finished time so side effects are triggered
+      runtimeState._timer.forceFinish = timeCore.timeOfDayNow();
+    } else {
+      const willGoPositive = runtimeState.timer.current < 0 && runtimeState.timer.current + amount > 0;
+      if (willGoPositive) {
+        runtimeState._timer.hasFinished = false;
+      }
     }
+
+    // we can update the state after handling the side effects
+    runtimeState.timer.addedTime += amount;
+    runtimeState.timer.current += amount;
   }
 
-  // we can update the state after handling the side effects
-  runtimeState.timer.addedTime += amount;
-  runtimeState.timer.current += amount;
   runtimeState.timer.elapsed = getElapsed(runtimeState);
 
   // update runtime delays: over - under
@@ -831,7 +841,6 @@ function getExpectedTimes(state = runtimeState) {
   state.offset.expectedRundownEnd = null;
   state.offset.expectedGroupEnd = null;
   state.offset.expectedFlagStart = null;
-  state.offset.expectedRundownEnd = null;
 
   const { offset } = state;
   const { plannedStart, actualStart } = state.rundown;
@@ -841,9 +850,11 @@ function getExpectedTimes(state = runtimeState) {
 
   if (state.groupNow) {
     const { _group } = state;
-    if (_group !== null) {
-      const { event: lastEvent, accumulatedGap, isLinkedToLoaded } = _group;
-      const lastEventExpectedStart = getExpectedStart(lastEvent, {
+    DEV: shouldCrashDev(_group === null, 'groupNow is set but _group is null');
+
+    if (_group) {
+      const { event, accumulatedGap, isLinkedToLoaded } = _group;
+      state.offset.expectedGroupEnd = getExpectedEnd(event, {
         currentDay: state.rundown.currentDay!,
         totalGap: accumulatedGap,
         isLinkedToLoaded,
@@ -852,15 +863,16 @@ function getExpectedTimes(state = runtimeState) {
         plannedStart,
         actualStart,
       });
-      state.offset.expectedGroupEnd = lastEventExpectedStart + lastEvent.duration;
     }
   }
 
   if (state.eventFlag) {
     const { _flag } = state;
+    DEV: shouldCrashDev(_flag === null, 'eventFlag is set but _flag is null');
+
     if (_flag) {
       const { event, accumulatedGap, isLinkedToLoaded } = _flag;
-      const expectedStart = getExpectedStart(event, {
+      state.offset.expectedFlagStart = getExpectedStart(event, {
         currentDay: state.rundown.currentDay!,
         totalGap: accumulatedGap,
         isLinkedToLoaded,
@@ -869,13 +881,13 @@ function getExpectedTimes(state = runtimeState) {
         plannedStart,
         actualStart,
       });
-      state.offset.expectedFlagStart = expectedStart;
     }
   }
 
   if (state._end) {
     const { event, accumulatedGap, isLinkedToLoaded } = state._end;
-    const expectedStart = getExpectedStart(event, {
+
+    state.offset.expectedRundownEnd = getExpectedEnd(event, {
       currentDay: state.rundown.currentDay!,
       totalGap: accumulatedGap,
       isLinkedToLoaded,
@@ -884,7 +896,6 @@ function getExpectedTimes(state = runtimeState) {
       plannedStart,
       actualStart,
     });
-    state.offset.expectedRundownEnd = expectedStart + event.duration;
   }
 }
 
@@ -927,6 +938,8 @@ export function loadGroupFlagAndEnd(
 
   let accumulatedGap = 0;
   let isLinkedToLoaded = true;
+  // a countToEnd event absorbs overtime and breaks the chain
+  let previousWasCountToEnd = false;
 
   for (let idx = currentIndex; idx < playableEventOrder.length; idx++) {
     const entry = entries[playableEventOrder[idx]];
@@ -935,7 +948,7 @@ export function loadGroupFlagAndEnd(
       if (idx !== currentIndex) {
         // we only accumulate data after the loaded event
         accumulatedGap += entry.gap;
-        isLinkedToLoaded = isLinkedToLoaded && entry.linkStart;
+        isLinkedToLoaded = isLinkedToLoaded && entry.linkStart && !previousWasCountToEnd;
 
         // and the loaded event is not allowed to be the next flag
         if (!foundFlag && metadata.flags.includes(entry.id)) {
@@ -949,6 +962,8 @@ export function loadGroupFlagAndEnd(
         foundGroupEnd = true;
         state._group = { event: lastEventInGroup, isLinkedToLoaded, accumulatedGap };
       }
+
+      previousWasCountToEnd = entry.countToEnd;
     }
   }
 

packages/utils/index.ts

@@ -80,7 +80,7 @@ export { validateEndAction, validateTimerType } from './src/validate-events/vali
 
 // feature business logic
 
-export { getExpectedStart } from './src/date-utils/getExpectedStart.js';
+export { getExpectedStart, getExpectedEnd } from './src/date-utils/getExpected.js';
 
 // feature business logic - rundown
 export { checkIsNow } from './src/date-utils/checkIsNow.js';

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

@@ -1,7 +1,7 @@
 import { Day, OffsetMode } from 'ontime-types';
 
 import { MILLIS_PER_HOUR, dayInMs } from './conversionUtils';
-import { getExpectedStart } from './getExpectedStart';
+import { getExpectedEnd, getExpectedStart } from './getExpected';
 
 describe('getExpectedStart()', () => {
   describe('Absolute offset mode', () => {
@@ -315,3 +315,124 @@ describe('getExpectedStart()', () => {
     expect(getExpectedStart(testEvent, { ...testState, currentDay: 0 })).toBe(23 * MILLIS_PER_HOUR + 5);
   });
 });
+
+describe('getExpectedEnd()', () => {
+  const baseState = {
+    currentDay: 0,
+    totalGap: 0,
+    mode: OffsetMode.Absolute,
+    actualStart: null,
+    plannedStart: null,
+    isLinkedToLoaded: true,
+  };
+
+  test('a regular event ends at its expected start plus duration', () => {
+    const testEvent = {
+      timeStart: 100,
+      duration: 50,
+      delay: 0,
+      dayOffset: 0 as Day,
+      countToEnd: false,
+    };
+
+    // on schedule
+    expect(getExpectedEnd(testEvent, { ...baseState, offset: 0 })).toBe(150);
+    // running 20 behind pushes the end out
+    expect(getExpectedEnd(testEvent, { ...baseState, offset: 20 })).toBe(170);
+  });
+
+  test('a countToEnd event pins to the planned end while in overtime', () => {
+    const testEvent = {
+      timeStart: 100,
+      duration: 50,
+      delay: 0,
+      dayOffset: 0 as Day,
+      countToEnd: true,
+    };
+
+    // overtime would otherwise push the end to 170, but countToEnd absorbs it and pins to 150
+    expect(getExpectedEnd(testEvent, { ...baseState, offset: 20 })).toBe(150);
+  });
+
+  test('an overnight countToEnd event returns a normalised end', () => {
+    // event starts at 23:00 and counts to 01:00 the next day -> duration spans midnight
+    const timeStart = 23 * MILLIS_PER_HOUR;
+    const duration = 2 * MILLIS_PER_HOUR;
+    const testEvent = {
+      timeStart,
+      duration,
+      delay: 0,
+      dayOffset: 0 as Day,
+      countToEnd: true,
+    };
+
+    expect(getExpectedEnd(testEvent, { ...baseState, offset: 0 })).toBe(timeStart + duration);
+  });
+
+  test('a countToEnd event ignores upstream delays and stays pinned to its fixed end', () => {
+    const testEvent = {
+      timeStart: 100,
+      duration: 50,
+      delay: 20,
+      dayOffset: 0 as Day,
+    };
+
+    // events shift their schedule based on delay...
+    expect(getExpectedEnd({ ...testEvent, countToEnd: false }, { ...baseState, offset: 0 })).toBe(170);
+    // ... but count to end events stay pinned to the scheduled end
+    expect(getExpectedEnd({ ...testEvent, countToEnd: true }, { ...baseState, offset: 0 })).toBe(150);
+  });
+
+  test('a countToEnd event drifts when a delay pushes its start past the fixed end', () => {
+    const testEvent = {
+      timeStart: 100,
+      duration: 50,
+      delay: 60,
+      dayOffset: 0 as Day,
+      countToEnd: true,
+    };
+
+    // the delayed start (160) is past the fixed end (150), so the event can no longer
+    // finish on time and the end follows the compromised start
+    expect(getExpectedEnd(testEvent, { ...baseState, offset: 0 })).toBe(160);
+  });
+
+  test('a countToEnd event on a later day keeps the day offset on the end', () => {
+    const testEvent = {
+      timeStart: 100,
+      duration: 50,
+      delay: 0,
+      dayOffset: 1 as Day,
+      countToEnd: true,
+    };
+
+    // the scheduled end must include the day offset (timeStart + dayInMs + duration),
+    // not collapse to the day-shifted start
+    expect(getExpectedEnd(testEvent, { ...baseState, currentDay: 0, offset: 0 })).toBe(150 + dayInMs);
+    // when the running event is already on the same day, no extra day is added
+    expect(getExpectedEnd({ ...testEvent, dayOffset: 0 as Day }, { ...baseState, currentDay: 0, offset: 0 })).toBe(150);
+  });
+
+  test('a countToEnd event is anchored to its wall-clock end in relative mode', () => {
+    const testEvent = {
+      timeStart: 100,
+      duration: 50,
+      delay: 0,
+      dayOffset: 0 as Day,
+      countToEnd: true,
+    };
+
+    const relativeState = {
+      ...baseState,
+      mode: OffsetMode.Relative,
+      actualStart: 30,
+      plannedStart: 0,
+      offset: 0,
+    };
+
+    // a regular event in the same state is shifted by the relative-start offset to 180
+    expect(getExpectedEnd({ ...testEvent, countToEnd: false }, relativeState)).toBe(180);
+    // the countToEnd event stays pinned to its wall-clock end (150), not shifted
+    expect(getExpectedEnd(testEvent, relativeState)).toBe(150);
+  });
+});

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

@@ -4,25 +4,21 @@ import { OffsetMode } from 'ontime-types';
 import { dayInMs } from './conversionUtils.js';
 
 /**
- * @param event the event that we are counting to
- * @param currentDay the day offset of the currently running event
- * @param totalGap accumulated gap from the current event
- * @param isLinkedToLoaded is this event part of a chain linking back to the current loaded event
- * @param clock
- * @param offset
- * @returns
+ * Runtime context shared by the expected start/end calculations
  */
+type ExpectedTimesState = {
+  currentDay: number; // the current day from the rundown
+  totalGap: number; // accumulated gap from the current event
+  isLinkedToLoaded: boolean; // is this event part of a chain linking back to the loaded event
+  offset: number;
+  mode: OffsetMode;
+  actualStart: MaybeNumber;
+  plannedStart: MaybeNumber;
+};
+
 export function getExpectedStart(
   event: Pick<OntimeEvent, 'timeStart' | 'dayOffset' | 'delay'>,
-  state: {
-    currentDay: number; // the current day from the rundown
-    totalGap: number;
-    isLinkedToLoaded: boolean;
-    offset: number;
-    mode: OffsetMode;
-    actualStart: MaybeNumber;
-    plannedStart: MaybeNumber;
-  },
+  state: ExpectedTimesState,
 ): number {
   const { timeStart, dayOffset, delay } = event;
   const { currentDay, totalGap, isLinkedToLoaded, offset, mode, actualStart, plannedStart } = state;
@@ -60,3 +56,27 @@ export function getExpectedStart(
   const offsetStartTimeBufferedByGaps = offsetStartTime - totalGap;
   return offsetStartTimeBufferedByGaps;
 }
+
+export function getExpectedEnd(
+  event: Pick<OntimeEvent, 'timeStart' | 'dayOffset' | 'delay' | 'duration' | 'countToEnd'>,
+  state: ExpectedTimesState,
+): number {
+  // expected start includes the delay and any offset compensation
+  const expectedStart = getExpectedStart(event, state);
+
+  /**
+   * Count to end events are a special case
+   * - the end time is always the wall clock
+   */
+  if (event.countToEnd) {
+    // account for day offset
+    const relativeDayOffset = event.dayOffset - state.currentDay;
+    const plannedEnd = event.timeStart + event.duration + relativeDayOffset * dayInMs;
+
+    // count to end should finish on the planned time or on start
+    return Math.max(expectedStart, plannedEnd);
+  }
+
+  // for normal events, the expected end is when we would start + its duration
+  return expectedStart + event.duration;
+}