Expose recurrence time zone in calendar events for #591

src/Orbit.Application/Calendar/Queries/GetCalendarEventsQuery.cs

@@ -24,7 +24,8 @@
     DateTime? StartUtc = null,
     string CalendarId = "",
     string CalendarName = "",
-    DateTime? EndUtc = null)
+    DateTime? EndUtc = null,
+    string? RecurrenceTimeZone = null)
 {
     /// <summary>
     /// The IANA zone the source calendar expands this event's recurrence in, taken from the recurring
@@ -241,7 +242,7 @@
     IUnitOfWork unitOfWork,
     ILogger<GetCalendarEventsQueryHandler> logger) : IRequestHandler<GetCalendarEventsQuery, Result<List<CalendarEventItem>>>
 {
     public async Task<Result<List<CalendarEventItem>>> Handle(GetCalendarEventsQuery request, CancellationToken cancellationToken)
     {
         var gateCheck = await payGate.CanAccessCalendar(request.UserId, cancellationToken);
         if (gateCheck.IsFailure)

src/Orbit.Application/Calendar/StoredCalendarEventJson.cs

@@ -35,10 +35,15 @@ internal static string Serialize(CalendarEventItem item)
         if (item is null)
             return null;
 
+        var sourceTimeZone = ReadSourceTimeZone(stored);
         return item with
         {
-            SourceTimeZone = ReadSourceTimeZone(stored),
-            RecurrenceStartUtc = ReadRecurrenceStartUtc(stored)
+            SourceTimeZone = sourceTimeZone,
+            RecurrenceStartUtc = ReadRecurrenceStartUtc(stored),
+            RecurrenceTimeZone = item.IsRecurring && item.StartTime is not null
+                && !string.IsNullOrWhiteSpace(sourceTimeZone)
+                ? sourceTimeZone
+                : null
         };
     }
 

src/Orbit.Infrastructure/Services/GoogleCalendarEventFetcher.cs

@@ -145,12 +145,15 @@
             ResolveStartUtc(ev.Start),
             calendarId,
             calendarName,
-            ev.End?.DateTimeDateTimeOffset?.UtcDateTime)
+            ev.End?.DateTimeDateTimeOffset?.UtcDateTime,
+            isRecurring && startTime is not null && !string.IsNullOrWhiteSpace(recurrence.TimeZone)
+                ? recurrence.TimeZone
+                : null)
         {
             SourceTimeZone = recurrence.TimeZone,
             RecurrenceStartUtc = !isRecurring
                 ? null
                 : ev.RecurringEventId is not null
                     ? ev.OriginalStartTime?.DateTimeDateTimeOffset?.UtcDateTime
                     : ev.Start?.DateTimeDateTimeOffset?.UtcDateTime
         };

tests/Orbit.Application.Tests/Queries/Calendar/CalendarEventItemSerializationTests.cs

@@ -21,11 +21,13 @@ public class CalendarEventItemSerializationTests
     public void ResponseBody_CarriesEndUtcAndOmitsTheSourceTimeZone()
     {
         var json = JsonSerializer.Serialize(LisbonSeries(), ResponseOptions);
+        using var response = JsonDocument.Parse(json);
 
         json.Should().NotContainEquivalentOf("sourceTimeZone");
         json.Should().NotContainEquivalentOf("recurrenceStartUtc");
-        json.Should().NotContain("Europe/Lisbon");
         json.Should().Contain("endUtc");
+        response.RootElement.TryGetProperty("recurrenceTimeZone", out var zone).Should().BeTrue();
+        zone.GetString().Should().Be("Europe/Lisbon");
     }
 
     [Fact]
@@ -34,16 +36,35 @@ public void StoredRow_CarriesTheSourceTimeZoneAndReadsItBack()
         var stored = StoredCalendarEventJson.Serialize(LisbonSeries());
 
         stored.Should().Contain("Europe/Lisbon");
+        var legacy = JsonNode.Parse(stored)!.AsObject();
+        legacy.Remove(nameof(CalendarEventItem.RecurrenceTimeZone));
 
-        var readBack = StoredCalendarEventJson.Deserialize(stored);
+        var readBack = StoredCalendarEventJson.Deserialize(legacy.ToJsonString());
 
         readBack.Should().NotBeNull();
         readBack!.SourceTimeZone.Should().Be("Europe/Lisbon");
+        readBack.RecurrenceTimeZone.Should().Be("Europe/Lisbon");
         readBack.RecurrenceStartUtc.Should().Be(new DateTime(2027, 1, 7, 3, 30, 0, DateTimeKind.Utc));
         readBack.Id.Should().Be("master-lisbon");
         readBack.EndUtc.Should().Be(new DateTime(2027, 1, 7, 4, 0, 0, DateTimeKind.Utc));
     }
 
+    [Theory]
+    [InlineData(true, null)]
+    [InlineData(false, "03:30")]
+    public void StoredRow_OnlyTimedRecurrencesExposeTheSourceTimeZone(bool isRecurring, string? startTime)
+    {
+        var item = LisbonSeries() with { IsRecurring = isRecurring, StartTime = startTime };
+        var legacy = JsonNode.Parse(StoredCalendarEventJson.Serialize(item))!.AsObject();
+        legacy.Remove(nameof(CalendarEventItem.RecurrenceTimeZone));
+
+        var readBack = StoredCalendarEventJson.Deserialize(legacy.ToJsonString());
+
+        readBack.Should().NotBeNull();
+        readBack!.SourceTimeZone.Should().Be("Europe/Lisbon");
+        readBack.RecurrenceTimeZone.Should().BeNull();
+    }
+
     /// <summary>
     /// A row written before the key existed reads back with no source zone, which the recurrence gate
     /// already treats as unproved. A row whose key holds a number must read back the same way rather
@@ -78,7 +99,8 @@ private static CalendarEventItem LisbonSeries()
             "RRULE:FREQ=DAILY;BYDAY=TH",
             [],
             StartUtc: new DateTime(2027, 1, 7, 3, 30, 0, DateTimeKind.Utc),
-            EndUtc: new DateTime(2027, 1, 7, 4, 0, 0, DateTimeKind.Utc))
+            EndUtc: new DateTime(2027, 1, 7, 4, 0, 0, DateTimeKind.Utc),
+            RecurrenceTimeZone: "Europe/Lisbon")
         {
             SourceTimeZone = "Europe/Lisbon",
             RecurrenceStartUtc = new DateTime(2027, 1, 7, 3, 30, 0, DateTimeKind.Utc)

tests/Orbit.Application.Tests/Queries/Calendar/GetCalendarSyncSuggestionsQueryHandlerTests.cs

@@ -305,6 +305,47 @@ public async Task Handle_LegacyTimedSuggestionWithoutEndUtc_MatchesEventsQueryPr
         result.Value[0].Event.EndTime.Should().BeNull();
     }
 
+    [Fact]
+    public async Task Handle_LegacyRecurringSuggestion_ExposesStoredSourceTimeZone()
+    {
+        var user = User.Create("Test", "test@example.com").Value;
+        user.SetTimeZone("America/Sao_Paulo").IsSuccess.Should().BeTrue();
+        _userRepo.GetByIdAsync(Arg.Any<Guid>(), Arg.Any<CancellationToken>()).Returns(user);
+
+        var startUtc = new DateTime(2026, 4, 15, 15, 0, 0, DateTimeKind.Utc);
+        var eventItem = new CalendarEventItem(
+            "event-legacy-recurring",
+            "Weekly review",
+            null,
+            "2026-04-15",
+            "12:00",
+            "13:00",
+            true,
+            "RRULE:FREQ=WEEKLY;BYDAY=WE",
+            [],
+            StartUtc: startUtc,
+            EndUtc: startUtc.AddHours(1))
+        {
+            SourceTimeZone = "America/Sao_Paulo",
+            RecurrenceStartUtc = startUtc
+        };
+        var legacyJson = JsonNode.Parse(StoredCalendarEventJson.Serialize(eventItem))!.AsObject();
+        legacyJson.Remove(nameof(CalendarEventItem.RecurrenceTimeZone));
+        var suggestion = GoogleCalendarSyncSuggestion.Create(
+            UserId, "gcal-legacy-recurring", eventItem.Title, startUtc, legacyJson.ToJsonString(), startUtc);
+
+        _suggestionRepo.FindAsync(
+            Arg.Any<Expression<Func<GoogleCalendarSyncSuggestion, bool>>>(),
+            Arg.Any<CancellationToken>())
+            .Returns(new List<GoogleCalendarSyncSuggestion> { suggestion }.AsReadOnly());
+
+        var result = await _handler.Handle(new GetCalendarSyncSuggestionsQuery(UserId), CancellationToken.None);
+
+        result.IsSuccess.Should().BeTrue();
+        result.Value.Should().ContainSingle();
+        result.Value[0].Event.RecurrenceTimeZone.Should().Be("America/Sao_Paulo");
+    }
+
     [Fact]
     public async Task Handle_TimedSuggestionCrossingLocalMidnight_OmitsEndTime()
     {

tests/Orbit.Infrastructure.Tests/Services/CalendarProjectionEndToEndTests.cs

@@ -87,6 +87,7 @@ public async Task ByDaySeriesReadFromItsOwnZone_IsOffered()
         result.IsSuccess.Should().BeTrue();
         result.Value.Should().ContainSingle();
         result.Value[0].RecurrenceRule.Should().Be("RRULE:FREQ=DAILY;BYDAY=TH");
+        result.Value[0].RecurrenceTimeZone.Should().Be("Europe/Lisbon");
         result.Value[0].StartDate.Should().Be("2027-01-07");
         result.Value[0].StartTime.Should().Be("03:30");
     }

tests/Orbit.Infrastructure.Tests/Services/GoogleCalendarEventFetcherTests.cs

@@ -1,3 +1,4 @@
+using System.Text.Json;
 using FluentAssertions;
 using Google.Apis.Calendar.v3.Data;
 using Microsoft.Extensions.Logging;
@@ -15,6 +16,7 @@ public class GoogleCalendarEventFetcherTests
     private readonly GoogleCalendarEventFetcher _fetcher;
 
     private const string Token = "access-token";
+    private static readonly JsonSerializerOptions ResponseOptions = new(JsonSerializerDefaults.Web);
 
     private static readonly string[] SharedCalendarSelection = new[] { "shared" };
     private static readonly string[] ChosenCalendarSelection = new[] { "chosen" };
@@ -148,7 +150,7 @@ public async Task FetchAsync_AllDayEvent_PreservesFloatingDateWithNullTimes()
             {
                 Id = "all-day-event",
                 Summary = "Holiday",
-                Start = new EventDateTime { Date = "2026-04-15" },
+                Start = new EventDateTime { Date = "2026-04-15", TimeZone = "Europe/Lisbon" },
                 End = new EventDateTime { Date = "2026-04-16" }
             });
 
@@ -160,6 +162,9 @@ public async Task FetchAsync_AllDayEvent_PreservesFloatingDateWithNullTimes()
         result[0].EndTime.Should().BeNull();
         result[0].StartUtc.Should().Be(new DateTime(2026, 4, 15, 0, 0, 0, DateTimeKind.Utc));
         result[0].EndUtc.Should().BeNull("Google's all-day end date is exclusive, so it is not the end instant");
+        var response = JsonSerializer.SerializeToElement(result[0], ResponseOptions);
+        response.TryGetProperty("recurrenceTimeZone", out var zone).Should().BeTrue();
+        zone.ValueKind.Should().Be(JsonValueKind.Null);
     }
 
     [Fact]
@@ -232,6 +237,9 @@ public async Task FetchAsync_RecurringInstance_TakesTheRuleAndZoneFromTheMaster(
         result[0].StartUtc.Should().Be(new DateTime(2027, 1, 7, 3, 30, 0, DateTimeKind.Utc));
         result[0].RecurrenceRule.Should().Be("RRULE:FREQ=DAILY;BYDAY=TH");
         result[0].SourceTimeZone.Should().Be("Europe/Lisbon");
+        var response = JsonSerializer.SerializeToElement(result[0], ResponseOptions);
+        response.TryGetProperty("recurrenceTimeZone", out var zone).Should().BeTrue();
+        zone.GetString().Should().Be("Europe/Lisbon");
         await _api.Received(1).GetEventAsync(Token, "a", "master-lisbon", Arg.Any<CancellationToken>());
     }
 
@@ -253,6 +261,9 @@ public async Task FetchAsync_RecurringInstance_IgnoresTheInstanceTimeZone()
 
         result.Should().ContainSingle();
         result[0].SourceTimeZone.Should().Be("Europe/Lisbon");
+        var response = JsonSerializer.SerializeToElement(result[0], ResponseOptions);
+        response.TryGetProperty("recurrenceTimeZone", out var zone).Should().BeTrue();
+        zone.GetString().Should().Be("Europe/Lisbon");
     }
 
     [Fact]