From ee2281fe8145e80206191df64c8a93c581547136 Mon Sep 17 00:00:00 2001
From: Lucas Berger <me@lucasberger.ca>
Date: Fri, 5 Jun 2026 14:33:00 -0400
Subject: [PATCH] fix(02): correct DURATION-only event end in expand.ts (BUG 1)

- Replace dtend ?? dtstart with event.endDate which handles DURATION-only VEVENTs
- Add positive-duration guard (PT30M / P1D) to both non-recurring and recurring branches
- Add single-duration.ics fixture and regression test asserting end > start for DURATION-only events
---
 apps/api/src/broker/expand.ts               | 28 ++++++++++++++--
 apps/api/tests/broker/expand.test.ts        | 36 +++++++++++++++++++++
 apps/api/tests/fixtures/single-duration.ics | 28 ++++++++++++++++
 3 files changed, 89 insertions(+), 3 deletions(-)
 create mode 100644 apps/api/tests/fixtures/single-duration.ics

diff --git a/apps/api/src/broker/expand.ts b/apps/api/src/broker/expand.ts
index 3a7f016..a38f58b 100644
--- a/apps/api/src/broker/expand.ts
+++ b/apps/api/src/broker/expand.ts
@@ -207,9 +207,22 @@ export function expandOccurrences(
   // --- 4. Non-recurring event: single occurrence check ---
   if (!event.isRecurring()) {
     if (dtstart.compare(rangeStart) >= 0 && dtstart.compare(rangeEnd) < 0) {
-      const dtend = (vevent.getFirstPropertyValue('dtend') as ICAL.Time | null) ?? dtstart
+      // Use ICAL.Event.endDate which derives end from DTEND, or DTSTART+DURATION, or sensible default.
+      // Do NOT use getFirstPropertyValue('dtend') directly — events with only DURATION set return null,
+      // producing zero-duration occurrences (BUG 1).
+      let occEnd: ICAL.Time = (event.endDate ?? dtstart) as ICAL.Time
+
+      // Positive-duration guard: ensure timed events have non-zero height in Schedule-X.
+      if (!allDay && occEnd.compare(dtstart) <= 0) {
+        occEnd = dtstart.clone()
+        occEnd.addDuration(ICAL.Duration.fromString('PT30M'))
+      } else if (allDay && occEnd.compare(dtstart) <= 0) {
+        occEnd = dtstart.clone()
+        occEnd.addDuration(ICAL.Duration.fromString('P1D'))
+      }
+
       const start = serializeTime(dtstart, allDay)
-      const end = serializeTime(dtend, allDay)
+      const end = serializeTime(occEnd, allDay)
       occurrences.push({
         id: makeOccurrenceId(uid, dtstart),
         uid,
@@ -240,9 +253,18 @@ export function expandOccurrences(
 
     // Compute occurrence end from event duration
     const duration = event.duration
-    const occEnd = next.clone()
+    let occEnd = next.clone()
     occEnd.addDuration(duration)
 
+    // Positive-duration guard: same logic as non-recurring branch above.
+    if (!allDay && occEnd.compare(next) <= 0) {
+      occEnd = next.clone()
+      occEnd.addDuration(ICAL.Duration.fromString('PT30M'))
+    } else if (allDay && occEnd.compare(next) <= 0) {
+      occEnd = next.clone()
+      occEnd.addDuration(ICAL.Duration.fromString('P1D'))
+    }
+
     const start = serializeTime(next, allDay)
     const end = serializeTime(occEnd, allDay)
 
diff --git a/apps/api/tests/broker/expand.test.ts b/apps/api/tests/broker/expand.test.ts
index a80d333..0267e6e 100644
--- a/apps/api/tests/broker/expand.test.ts
+++ b/apps/api/tests/broker/expand.test.ts
@@ -140,6 +140,42 @@ describe('expandOccurrences', () => {
     })
   })
 
+  describe('Non-recurring DURATION-only event — single-duration.ics', () => {
+    it('BUG-1 regression: non-recurring event with DURATION but no DTEND has end strictly after start', () => {
+      // Real Fastmail events use DURATION (not DTEND). Before the fix, the NON-RECURRING branch
+      // used getFirstPropertyValue('dtend') ?? dtstart, which returned dtstart when DTEND was absent,
+      // producing zero-duration occurrences (invisible in week/day views).
+      const rawVevent = loadFixture('single-duration.ics')
+      const windowStart = new Date('2026-06-01T00:00:00Z')
+      const windowEnd = new Date('2026-07-01T00:00:00Z')
+
+      const occurrences = expandOccurrences(
+        rawVevent,
+        windowStart,
+        windowEnd,
+        1,
+        'My Calendar',
+        1,
+        '#4A90D9',
+        false,
+      )
+
+      expect(occurrences.length).toBe(1)
+
+      const occ = occurrences[0]
+      expect(occ.allDay).toBe(false)
+
+      // Parse both via Temporal.ZonedDateTime and assert end > start
+      const startZdt = Temporal.ZonedDateTime.from(occ.start)
+      const endZdt = Temporal.ZonedDateTime.from(occ.end)
+      expect(Temporal.ZonedDateTime.compare(endZdt, startZdt)).toBeGreaterThan(0)
+
+      // Verify the actual duration is correct: DURATION:PT1H → end is 1 hour after start
+      expect(endZdt.hour - startZdt.hour).toBe(1)
+      expect(endZdt.minute).toBe(startZdt.minute)
+    })
+  })
+
   describe('Cross-contract: expand output → Temporal.ZonedDateTime.from (regression guard)', () => {
     it('timed event start/end strings from weekly-dst.ics parse via Temporal.ZonedDateTime.from without throwing', () => {
       // This is the integration test that was missing. It takes the actual serializeTime output
diff --git a/apps/api/tests/fixtures/single-duration.ics b/apps/api/tests/fixtures/single-duration.ics
new file mode 100644
index 0000000..46bd923
--- /dev/null
+++ b/apps/api/tests/fixtures/single-duration.ics
@@ -0,0 +1,28 @@
+BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//FamilySync//Test//EN
+BEGIN:VTIMEZONE
+TZID:America/Toronto
+BEGIN:STANDARD
+DTSTART:19701101T020000
+RRULE:FREQ=YEARLY;BYDAY=1SU;BYMONTH=11
+TZOFFSETFROM:-0400
+TZOFFSETTO:-0500
+TZNAME:EST
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:19700308T020000
+RRULE:FREQ=YEARLY;BYDAY=2SU;BYMONTH=3
+TZOFFSETFROM:-0500
+TZOFFSETTO:-0400
+TZNAME:EDT
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VEVENT
+UID:single-duration-only@familysync.test
+DTSTART;TZID=America/Toronto:20260618T080000
+DURATION:PT1H
+SUMMARY:Morning Standup
+DESCRIPTION:Non-recurring timed event with DURATION only, no DTEND
+END:VEVENT
+END:VCALENDAR