refactor: event instances

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

tests/js/unit/occurrenceIndex.test.ts

@@ -66,6 +66,21 @@ describe('occurrence index', () => {
     expect(occurrencesForDay(index, new Date(2026, 5, 21))).toHaveLength(0)
   })
 
+  it('treats UTC timestamps on timeless events as floating calendar dates', () => {
+    const allDay = eventEntity(
+      'utc-all-day',
+      '2025-03-27T00:00:00+00:00',
+      '2025-03-28T00:00:00+00:00',
+      true,
+    )
+    const index = buildOccurrenceIndex([allDay])
+
+    expect(occurrencesForDay(index, new Date(2025, 2, 26))).toHaveLength(0)
+    expect(occurrencesForDay(index, new Date(2025, 2, 27))).toHaveLength(1)
+    expect(occurrencesForDay(index, new Date(2025, 2, 28))).toHaveLength(0)
+    expect(new Date(index.sorted[0].startMs).getHours()).toBe(0)
+  })
+
   it('retrieves overlapping occurrences without duplicates', () => {
     const spanning = eventEntity(
       'spanning',

tests/js/unit/recurrence.test.ts

@@ -87,6 +87,32 @@ describe('daily recurrence', () => {
 
     expect(occurrences.map(occurrence => new Date(occurrence.startMs).getHours())).toEqual([9, 9, 9])
   })
+
+  it('preserves exclusive calendar-day duration for recurring timeless events', () => {
+    const entity = recurringEntity({
+      pattern: 'absolute',
+      precision: 'daily',
+      interval: 1,
+    }, {}, '2026-03-07T00:00:00+00:00')
+    const event = entity.properties as unknown as {
+      endsOn: string
+      timeless: boolean
+    }
+    event.endsOn = '2026-03-08T00:00:00+00:00'
+    event.timeless = true
+
+    const occurrences = expandEntityOccurrences(
+      entity,
+      daysVisibleRange(new Date(2026, 2, 7), 3),
+    )
+
+    expect(occurrences).toHaveLength(3)
+    expect(occurrences.map(occurrence => new Date(occurrence.startMs).getHours())).toEqual([0, 0, 0])
+    expect(occurrences.map(occurrence => {
+      const end = new Date(occurrence.endMs)
+      return [end.getDate(), end.getHours()]
+    })).toEqual([[8, 0], [9, 0], [10, 0]])
+  })
 })
 
 describe('weekly recurrence', () => {