fix: count-to-end events break link chain

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;
+}