fix: iCal DTEND rolls to the next day for midnight-straddling sets

functions/api/feeds/__tests__/ical.test.js

@@ -479,3 +479,72 @@ describe("GET /api/feeds/ical — day-aware performance_date (real-DB)", () => {
     expect(idxLate).toBeLessThan(idxMorning);
   });
 });
+
+// ---------------------------------------------------------------------------
+// #601 — a set that STRADDLES midnight (23:30–00:30) must stamp DTEND with the
+// next calendar day; same-date stamps would put DTEND before DTSTART, an
+// invalid VEVENT. Distinct from pure after-midnight sets (start 00:00–05:59),
+// which correctly keep both stamps on the stored date (covered above).
+// ---------------------------------------------------------------------------
+describe("GET /api/feeds/ical — midnight-straddling DTEND rolls to the next day (#601)", () => {
+  test("23:30–00:30 set: DTSTART on the stored date, DTEND on the following day", async () => {
+    const { env, rawDb } = createTestEnv();
+    env.PUBLIC_DATA_PUBLISH_ENABLED = "true";
+
+    const event = insertEvent(rawDb, {
+      name: "Straddle Ical Event",
+      slug: "ical-straddle",
+      date: "2099-03-01",
+    });
+    rawDb.prepare("UPDATE events SET is_published=1 WHERE id=?").run(event.id);
+    const venue = insertVenue(rawDb, { name: "Room 47" });
+
+    insertBand(rawDb, {
+      name: "Straddle Band",
+      event_id: event.id,
+      venue_id: venue.id,
+      start_time: "23:30",
+      end_time: "00:30",
+    });
+
+    const request = new Request("https://example.test/api/feeds/ical");
+    const response = await onRequestGet({ request, env });
+
+    expect(response.status).toBe(200);
+    const icalData = await response.text();
+
+    expect(icalData).toContain("DTSTART:20990301T233000");
+    expect(icalData).toContain("DTEND:20990302T003000");
+    expect(icalData).not.toContain("DTEND:20990301T003000");
+  });
+
+  test("month boundary: 23:00–00:15 on March 31 stamps DTEND April 1", async () => {
+    const { env, rawDb } = createTestEnv();
+    env.PUBLIC_DATA_PUBLISH_ENABLED = "true";
+
+    const event = insertEvent(rawDb, {
+      name: "Month Boundary Ical Event",
+      slug: "ical-month-boundary",
+      date: "2099-03-31",
+    });
+    rawDb.prepare("UPDATE events SET is_published=1 WHERE id=?").run(event.id);
+    const venue = insertVenue(rawDb, { name: "Princess Cafe" });
+
+    insertBand(rawDb, {
+      name: "Boundary Band",
+      event_id: event.id,
+      venue_id: venue.id,
+      start_time: "23:00",
+      end_time: "00:15",
+    });
+
+    const request = new Request("https://example.test/api/feeds/ical");
+    const response = await onRequestGet({ request, env });
+
+    expect(response.status).toBe(200);
+    const icalData = await response.text();
+
+    expect(icalData).toContain("DTSTART:20990331T230000");
+    expect(icalData).toContain("DTEND:20990401T001500");
+  });
+});

functions/api/feeds/ical.js

@@ -111,9 +111,18 @@ function generateICal(bands, city, genre) {
     const startTime = band.start_time || "20:00"; // HH:MM
     const endTime = band.end_time || "21:00";
 
+    // A set that straddles midnight (e.g. 23:30–00:30) ENDS on the next
+    // calendar day — stamping both ends with the same date would put DTEND
+    // before DTSTART, an invalid VEVENT some clients reject (#601). Zero-padded
+    // HH:MM compares lexicographically; this mirrors prepareBands()'s
+    // `endMs < startMs` +1-day roll in frontend/src/utils/bandUtils.js. Pure
+    // after-midnight sets (start 00:00–05:59) are unaffected: both stamps
+    // correctly share the stored date.
+    const endDate = endTime < startTime ? nextCalendarDay(eventDate) : eventDate;
+
     // Convert to iCal format (YYYYMMDDTHHMMSS)
     const dtstart = `${eventDate.replace(/-/g, "")}T${startTime.replace(/:/g, "")}00`;
-    const dtend = `${eventDate.replace(/-/g, "")}T${endTime.replace(/:/g, "")}00`;
+    const dtend = `${endDate.replace(/-/g, "")}T${endTime.replace(/:/g, "")}00`;
 
     // Generate unique ID using performance ID to ensure uniqueness per band
     const uid = `performance-${band.performance_id}-${eventDate}@settimes.ca`;
@@ -145,6 +154,16 @@ function generateICal(bands, city, genre) {
   return ical.join("\r\n");
 }
 
+/**
+ * YYYY-MM-DD → the following calendar day, DST-proof via UTC math (the
+ * string is a date literal, not a moment in time).
+ */
+function nextCalendarDay(dateStr) {
+  const next = new Date(`${dateStr}T00:00:00Z`);
+  next.setUTCDate(next.getUTCDate() + 1);
+  return next.toISOString().slice(0, 10);
+}
+
 function escapeIcal(text) {
   if (!text) return "";
   return text