refactor: finish of count-to-end is plan or start time

apps/server/package.json

@@ -42,7 +42,7 @@
   "scripts": {
     "addversion": "node -p \"'export const ONTIME_VERSION = ' + JSON.stringify(require('../../package.json').version) + ';'\" > src/ONTIME_VERSION.js",
     "postinstall": "pnpm addversion",
-    "dev": "cross-env NODE_ENV=development tsx watch --tsconfig tsconfig.app.json ./src/index.ts",
+    "dev": "cross-env PORT=4001 NODE_ENV=development tsx watch --tsconfig tsconfig.app.json ./src/index.ts",
     "dev:electron": "pnpm dev",
     "dev:inspect": "cross-env NODE_ENV=development tsx watch --tsconfig tsconfig.app.json --inspect ./src/index.ts",
     "lint": "oxlint --quiet --type-aware",

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

@@ -268,29 +268,31 @@ describe('getExpectedFinish()', () => {
       const calculatedFinish = getExpectedFinish(state);
       expect(calculatedFinish).toBe(30);
     });
-    it('handles events that finish the day after', () => {
+
+    it('returns the start time for count to end times which started late', () => {
       const state = {
         eventNow: {
-          timeEnd: 600000, // 00:10:00
+          timeStart: 20 * MILLIS_PER_HOUR, // 20:00:00
+          timeEnd: 21 * MILLIS_PER_MINUTE, // 21:00:00
           countToEnd: true,
         },
         timer: {
           addedTime: 0,
-          startedAt: 79200000, // 22:00:00
+          startedAt: 22 * MILLIS_PER_HOUR, // 22:00:00 <--------------
         },
         _timer: {
           pausedAt: null,
           hasFinished: false,
         },
         rundown: {
-          actualStart: 79200000,
-          plannedEnd: 600000,
+          actualStart: 20 * MILLIS_PER_HOUR, // 20:00:00
+          plannedEnd: 21 * MILLIS_PER_HOUR, // 21:00:00
         },
       } as RuntimeState;
 
       const calculatedFinish = getExpectedFinish(state);
-      // expected finish is not a duration but a point in time
-      expect(calculatedFinish).toBe(600000);
+      // timeEnd is numerically before startedAt for overnight events, so expectedFinish is clamped to startedAt
+      expect(calculatedFinish).toBe(22 * MILLIS_PER_HOUR);
     });
   });
 });

apps/server/src/services/generic.errors.ts

@@ -0,0 +1,9 @@
+/**
+ * Expose errors where we reach invalid states
+ * used mostly in shouldCrashDev patterns
+ */
+export class InvalidStateError extends Error {
+  constructor(message: string) {
+    super(message);
+  }
+}

apps/server/src/services/timerUtils.ts

@@ -2,6 +2,7 @@ import { Day, MaybeNumber, TimeOfDay, TimerPhase } from 'ontime-types';
 import { MILLIS_PER_HOUR, checkIsNow, dayInMs, isPlaybackActive } from 'ontime-utils';
 
 import type { RuntimeState } from '../stores/runtimeState.js';
+import { InvalidStateError } from './generic.errors.js';
 
 /**
  * handle events that span over midnight
@@ -24,37 +25,35 @@ export function hasCrossedMidnight(previous: TimeOfDay, current: TimeOfDay): boo
  * @returns {number | null} new current time or null if nothing is running
  */
 export function getExpectedFinish(state: RuntimeState): MaybeNumber {
-  const { startedAt, duration, addedTime } = state.timer;
-
-  if (state.eventNow === null) {
+  // if there is a loaded event it must have started
+  // either way, we have no expected finish if nothing is playing
+  if (state.eventNow === null || state.timer.startedAt === null) {
     return null;
   }
 
-  const { countToEnd, timeEnd } = state.eventNow;
-  const { pausedAt } = state._timer;
-  const { clock } = state;
-
-  if (startedAt === null) {
-    return null;
-  }
-
-  const pausedTime = pausedAt != null ? clock - pausedAt : 0;
-
-  if (countToEnd) {
+  if (state.eventNow.countToEnd) {
     // 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;
+    return Math.max(state.eventNow.timeEnd, state.timer.startedAt);
+  }
+
+  const pausedTime = state._timer.pausedAt != null ? state.clock - state._timer.pausedAt : 0;
+
+  DEV: {
+    if (state.timer.duration === null) {
+      throw new InvalidStateError('a running timer cannot have null duration');
+    }
   }
 
   // handle events that finish the day after
   // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- duration exists if ther eis a timer
-  const expectedFinish = startedAt + duration! + addedTime + pausedTime;
+  const expectedFinish = state.timer.startedAt + state.timer.duration + state.timer.addedTime + pausedTime;
   if (expectedFinish > dayInMs) {
     return expectedFinish - dayInMs;
   }
 
   // an event cannot finish before it started (user added too much negative time)
-  return Math.max(expectedFinish, startedAt);
+  return Math.max(expectedFinish, state.timer.startedAt);
 }
 
 /**