From 2ac840d84572b344c75a138fae4e2c86b3d097fc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jovan=20Kruni=C4=87?= <jovan.krunic@gmail.com>
Date: Mon, 4 Nov 2024 18:01:03 +0100
Subject: [PATCH] fix: observable immediately returns false if scheduled beyond
 max delay

Closes #229
---
 frontend/app/src/app/util/in-range.pipe.ts | 6 ++++--
 frontend/app/src/app/util/in-range.spec.ts | 4 ++++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/frontend/app/src/app/util/in-range.pipe.ts b/frontend/app/src/app/util/in-range.pipe.ts
index 093a1660..5a6ce53d 100644
--- a/frontend/app/src/app/util/in-range.pipe.ts
+++ b/frontend/app/src/app/util/in-range.pipe.ts
@@ -1,6 +1,6 @@
 import {Pipe, PipeTransform} from '@angular/core';
 import {SCRange, isInRange, SCISO8601DateRange} from '@openstapps/core';
-import {NormalizedInterval, differenceInMilliseconds, interval, isEqual} from 'date-fns';
+import {NormalizedInterval, differenceInMilliseconds, interval} from 'date-fns';
 import {EMPTY, Observable, SchedulerLike, asyncScheduler, concat, defer, map, of, timer} from 'rxjs';
 
 @Pipe({
@@ -16,6 +16,8 @@ export class InRangePipe implements PipeTransform {
 
 export const MIN_DATE = new Date(0);
 export const MAX_DATE = new Date(1e15);
+// Maximum safe delay for JavaScript timers (~24.8 days)
+export const MAX_DELAY = 2 ** 31 - 1;
 
 @Pipe({
   name: 'rangeToDateInterval',
@@ -43,7 +45,7 @@ export function isWithinIntervalObservable(
     return concat(
       of(activate <= 0 && deactivate > 0),
       activate <= 0 ? EMPTY : timer(value.start, scheduler).pipe(map(() => true)),
-      isEqual(value.end, MAX_DATE) || deactivate <= 0
+      differenceInMilliseconds(value.end, now) >= MAX_DELAY || deactivate <= 0
         ? EMPTY
         : timer(value.end, scheduler).pipe(map(() => false)),
     );
diff --git a/frontend/app/src/app/util/in-range.spec.ts b/frontend/app/src/app/util/in-range.spec.ts
index 836717b7..dc31df58 100644
--- a/frontend/app/src/app/util/in-range.spec.ts
+++ b/frontend/app/src/app/util/in-range.spec.ts
@@ -1,6 +1,7 @@
 import {TestScheduler} from 'rxjs/testing';
 import {MAX_DATE, MIN_DATE, isWithinIntervalObservable} from './in-range.pipe';
 import {interval} from 'date-fns';
+import {MAX_DELAY} from './in-range.pipe';
 
 /**
  * Test macro
@@ -39,4 +40,7 @@ describe('isWithinIntervalObservable', () => {
   test([500, 1000], '499ms ^', '499ms f t 499ms (f|)');
 
   test([500, 1000], '^ 750ms !', 'f 499ms t');
+
+  // Long interval test case: emit `true` and then complete (EMPTY) because `end` is beyond the delay limit
+  test([500, 500 + MAX_DELAY + 2000], '1s ^', '1s (t|)');
 });