fix: dedupe scheduling emails, Stalwart-compatible calendar filters

lib/__tests__/recurrence-expansion.test.ts

@@ -323,6 +323,89 @@ describe('expandRecurringEvents', () => {
     });
   });
 
+  // -----------------------------------------------------------------------
+  // excludedRecurrenceRules (EXRULE)
+  // -----------------------------------------------------------------------
+  describe('excludedRecurrenceRules', () => {
+    it('removes occurrences generated by excluded rules', () => {
+      const event = makeEvent({
+        recurrenceRules: [{ '@type': 'RecurrenceRule', frequency: 'daily' } as any],
+        excludedRecurrenceRules: [{
+          '@type': 'RecurrenceRule',
+          frequency: 'weekly',
+          byDay: [{ day: 'tu' }],
+        } as any],
+      });
+      // Jan 6-12 2025: Mon-Sun, Tuesday Jan 7 excluded
+      const result = expand(event, '2025-01-06T00:00:00', '2025-01-13T00:00:00');
+      const days = result.map(e => e.start.substring(0, 10));
+      expect(days).not.toContain('2025-01-07');
+      expect(days).toContain('2025-01-06');
+      expect(days).toContain('2025-01-08');
+      expect(result).toHaveLength(6);
+    });
+  });
+
+  // -----------------------------------------------------------------------
+  // Long-running series
+  // -----------------------------------------------------------------------
+  describe('long-running series', () => {
+    it('expands a daily series started years before the visible range', () => {
+      const event = makeEvent({
+        start: '2022-01-03T09:00:00',
+        recurrenceRules: [{ '@type': 'RecurrenceRule', frequency: 'daily' } as any],
+      });
+      const result = expand(event, '2025-06-02T00:00:00', '2025-06-05T00:00:00');
+      expect(starts(result)).toEqual([
+        '2025-06-02T09:00:00',
+        '2025-06-03T09:00:00',
+        '2025-06-04T09:00:00',
+      ]);
+    });
+
+    it('expands a weekly series started years before the visible range', () => {
+      const event = makeEvent({
+        start: '2020-01-06T09:00:00', // Monday
+        recurrenceRules: [{ '@type': 'RecurrenceRule', frequency: 'weekly' } as any],
+      });
+      const result = expand(event, '2025-06-01T00:00:00', '2025-06-30T00:00:00');
+      const days = result.map(e => e.start.substring(0, 10));
+      expect(days).toEqual(['2025-06-02', '2025-06-09', '2025-06-16', '2025-06-23']);
+    });
+
+    it('still respects count for old series (no fast-forward shortcut)', () => {
+      const event = makeEvent({
+        start: '2025-01-06T09:00:00',
+        recurrenceRules: [{ '@type': 'RecurrenceRule', frequency: 'daily', count: 5 } as any],
+      });
+      // Range far after the 5 occurrences ran out
+      const result = expand(event, '2025-06-01T00:00:00', '2025-06-30T00:00:00');
+      expect(result).toHaveLength(0);
+    });
+  });
+
+  // -----------------------------------------------------------------------
+  // Event-timezone DST handling
+  // -----------------------------------------------------------------------
+  describe('event timezone DST handling', () => {
+    it('keeps wall time across a DST transition in the event timezone', () => {
+      // America/New_York: EST (UTC-5) until 2025-03-09, EDT (UTC-4) after
+      const event = makeEvent({
+        start: '2025-03-03T10:00:00',
+        timeZone: 'America/New_York',
+        utcStart: '2025-03-03T15:00:00Z',
+        utcEnd: '2025-03-03T16:00:00Z',
+        recurrenceRules: [{ '@type': 'RecurrenceRule', frequency: 'weekly' } as any],
+      } as Partial<CalendarEvent>);
+      const result = expand(event, '2025-03-03T00:00:00', '2025-03-17T00:00:00');
+      const utcStarts = result.map(e => (e as any).utcStart);
+      expect(utcStarts[0]).toBe('2025-03-03T15:00:00.000Z'); // EST: 10:00 -5
+      expect(utcStarts[1]).toBe('2025-03-10T14:00:00.000Z'); // EDT: 10:00 -4
+      const utcEnds = result.map(e => (e as any).utcEnd);
+      expect(utcEnds[1]).toBe('2025-03-10T15:00:00.000Z');
+    });
+  });
+
   // -----------------------------------------------------------------------
   // All-day events
   // -----------------------------------------------------------------------