feat: accept client-style CalDAV week start rules; test all-day, TZID and alarm payloads

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/FamilyPlanner.Api/Features/CalDav/CalDavEndpoints.cs

@@ -486,7 +486,7 @@ public static class CalDavEndpoints
             return Error(StatusCodes.Status403Forbidden, C + "supported-calendar-component", "Der Familienplaner speichert nur Termine (VEVENT), keine Aufgaben oder Journale.");
         }
 
-        var parsed = IcsImporter.Parse(text, zone);
+        var parsed = IcsImporter.Parse(NormalizeWeekStart(text), zone);
         if (parsed.IsInvalid)
         {
             return Error(StatusCodes.Status403Forbidden, C + "valid-calendar-data", "Keine gültige iCalendar-Datei.");
@@ -520,6 +520,37 @@ public static class CalDavEndpoints
         return null;
     }
 
+    private static readonly Regex RuleLine = new(@"^RRULE:(?<rule>.*)$", RegexOptions.Multiline | RegexOptions.CultureInvariant);
+
+    /// <summary>
+    /// Android/Google senden oft <c>WKST=SU</c>. Der Wochenbeginn ändert die Termine nur bei „alle n Wochen“ (INTERVAL &gt; 1) mit mehreren Wochentagen;
+    /// in allen anderen Fällen ist er unerheblich und wird entfernt, damit die Regel in die unterstützte Teilmenge (WKST=MO) fällt. Sonst bleibt er stehen
+    /// und der Termin wird abgelehnt (ehrlicher als eine still abweichende Serie).
+    /// </summary>
+    internal static string NormalizeWeekStart(string ics) =>
+        RuleLine.Replace(ics, match =>
+        {
+            var rule = match.Groups["rule"].Value.TrimEnd('\r');
+            var parts = rule.Split(';').ToList();
+            var weekStart = parts.FirstOrDefault(p => p.StartsWith("WKST=", StringComparison.OrdinalIgnoreCase));
+            if (weekStart is null || weekStart.Equals("WKST=MO", StringComparison.OrdinalIgnoreCase))
+            {
+                return match.Value;
+            }
+
+            var weekly = parts.Contains("FREQ=WEEKLY", StringComparer.OrdinalIgnoreCase);
+            var interval = parts.FirstOrDefault(p => p.StartsWith("INTERVAL=", StringComparison.OrdinalIgnoreCase));
+            var intervalValue = interval is not null && int.TryParse(interval["INTERVAL=".Length..], out var n) ? n : 1;
+            var multipleDays = parts.FirstOrDefault(p => p.StartsWith("BYDAY=", StringComparison.OrdinalIgnoreCase)) is { } byDay && byDay.Contains(',', StringComparison.Ordinal);
+            if (weekly && intervalValue > 1 && multipleDays)
+            {
+                return match.Value;
+            }
+
+            parts.Remove(weekStart);
+            return "RRULE:" + string.Join(';', parts) + (match.Value.EndsWith('\r') ? "\r" : string.Empty);
+        });
+
     private static void Attach(CalendarEvent o, CalendarEvent master)
     {
         o.CalendarId = master.CalendarId;

tests/FamilyPlanner.IntegrationTests/CalDavTests.cs

@@ -250,6 +250,69 @@ public sealed class CalDavTests(AppFixture fixture)
         Assert.Equal(HttpStatusCode.Forbidden, (await DeleteAsync(dav, CalendarPath(calendarId))).Response.StatusCode);
     }
 
+    [Fact]
+    public async Task Client_style_payloads_all_day_events_tzid_with_vtimezone_and_alarm_and_week_start_roundtrip()
+    {
+        using var admin = await fixture.CreateAdminClientAsync(Ct);
+        var calendarId = await FamilyCalendarIdAsync(admin);
+        using var dav = DavClient(AppFixture.AdminUserName, await NewSecretAsync(admin));
+        var day = TestDay().Date;
+        string D8(DateTime d) => d.ToString("yyyyMMdd");
+
+        // Ganztägig, ein Tag (iOS: DTEND = Folgetag, exklusiv)
+        var single = Guid.NewGuid().ToString("D").ToUpperInvariant();
+        var singleIcs = Wrap($"BEGIN:VEVENT\r\nUID:{single}\r\nDTSTAMP:20400101T000000Z\r\nDTSTART;VALUE=DATE:{D8(day)}\r\nDTEND;VALUE=DATE:{D8(day.AddDays(1))}\r\nSUMMARY:Feiertag\r\nTRANSP:TRANSPARENT\r\nEND:VEVENT\r\n");
+        Assert.Equal(HttpStatusCode.Created, (await PutAsync(dav, ResourcePath(calendarId, single), singleIcs)).Response.StatusCode);
+
+        // Ganztägig, drei Tage (11.–13., DTEND = 14. exklusiv)
+        var multi = Guid.NewGuid().ToString("D").ToUpperInvariant();
+        var multiIcs = Wrap($"BEGIN:VEVENT\r\nUID:{multi}\r\nDTSTAMP:20400101T000000Z\r\nDTSTART;VALUE=DATE:{D8(day.AddDays(10))}\r\nDTEND;VALUE=DATE:{D8(day.AddDays(13))}\r\nSUMMARY:Urlaub\r\nEND:VEVENT\r\n");
+        Assert.Equal(HttpStatusCode.Created, (await PutAsync(dav, ResourcePath(calendarId, multi), multiIcs)).Response.StatusCode);
+
+        var range = (await RangeAsync(admin, day, day.AddDays(20))).Occurrences;
+        var feiertag = range.Single(o => o.Title == "Feiertag");
+        var urlaub = range.Single(o => o.Title == "Urlaub");
+        Assert.True(feiertag.IsAllDay);
+        Assert.Equal((DateOnly.FromDateTime(day), DateOnly.FromDateTime(day)), (feiertag.StartDate, feiertag.EndDate));
+        Assert.True(urlaub.IsAllDay);
+        Assert.Equal((DateOnly.FromDateTime(day.AddDays(10)), DateOnly.FromDateTime(day.AddDays(12))), (urlaub.StartDate, urlaub.EndDate)); // Ende im Web inklusiv
+
+        var singleGet = (await SendAsync(dav, HttpMethod.Get, ResourcePath(calendarId, single))).Body;
+        Assert.Contains($"DTSTART;VALUE=DATE:{D8(day)}", singleGet);
+        Assert.Contains($"DTEND;VALUE=DATE:{D8(day.AddDays(1))}", singleGet);
+        var multiGet = (await SendAsync(dav, HttpMethod.Get, ResourcePath(calendarId, multi))).Body;
+        Assert.Contains($"DTSTART;VALUE=DATE:{D8(day.AddDays(10))}", multiGet);
+        Assert.Contains($"DTEND;VALUE=DATE:{D8(day.AddDays(13))}", multiGet);
+
+        // erneutes Speichern durch den Client ändert nichts (kein Daten-Drift bei Ganztägig)
+        var etag = await ETagOfAsync(dav, ResourcePath(calendarId, multi));
+        Assert.Equal(HttpStatusCode.NoContent, (await PutAsync(dav, ResourcePath(calendarId, multi), multiGet)).Response.StatusCode);
+        Assert.Equal(etag, await ETagOfAsync(dav, ResourcePath(calendarId, multi)));
+
+        // iOS-Stil: TZID mit mitgeliefertem VTIMEZONE und VALARM
+        var timed = Guid.NewGuid().ToString("D").ToUpperInvariant();
+        var local = day.AddDays(3).AddHours(10);
+        var timedIcs = "BEGIN:VCALENDAR\r\nVERSION:2.0\r\nPRODID:-//Apple Inc.//iPhone OS 18//EN\r\nCALSCALE:GREGORIAN\r\n" +
+            "BEGIN:VTIMEZONE\r\nTZID:Europe/Berlin\r\nBEGIN:DAYLIGHT\r\nTZOFFSETFROM:+0100\r\nRRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU\r\nDTSTART:19810329T020000\r\nTZNAME:MESZ\r\nTZOFFSETTO:+0200\r\nEND:DAYLIGHT\r\n" +
+            "BEGIN:STANDARD\r\nTZOFFSETFROM:+0200\r\nRRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU\r\nDTSTART:19961027T030000\r\nTZNAME:MEZ\r\nTZOFFSETTO:+0100\r\nEND:STANDARD\r\nEND:VTIMEZONE\r\n" +
+            $"BEGIN:VEVENT\r\nCREATED:20400101T000000Z\r\nDTEND;TZID=Europe/Berlin:{local.AddHours(1):yyyyMMdd'T'HHmmss}\r\nDTSTAMP:20400101T000000Z\r\nDTSTART;TZID=Europe/Berlin:{local:yyyyMMdd'T'HHmmss}\r\nSEQUENCE:0\r\nSUMMARY:Zahnarzt iOS\r\nTRANSP:OPAQUE\r\nUID:{timed}\r\n" +
+            "BEGIN:VALARM\r\nACTION:DISPLAY\r\nDESCRIPTION:Erinnerung\r\nTRIGGER:-PT15M\r\nUID:ALARM-1\r\nEND:VALARM\r\nEND:VEVENT\r\nEND:VCALENDAR\r\n";
+        Assert.Equal(HttpStatusCode.Created, (await PutAsync(dav, ResourcePath(calendarId, timed), timedIcs)).Response.StatusCode);
+        var zahnarzt = (await RangeAsync(admin, local.Date, local.Date)).Occurrences.Single(o => o.Title == "Zahnarzt iOS");
+        Assert.Equal((new TimeOnly(10, 0), new TimeOnly(11, 0)), (zahnarzt.StartTime, zahnarzt.EndTime));
+        var timedGet = (await SendAsync(dav, HttpMethod.Get, ResourcePath(calendarId, timed))).Body;
+        Assert.Contains($"DTSTART;TZID=Europe/Berlin:{local:yyyyMMdd'T'HHmmss}", timedGet);
+        Assert.DoesNotContain("VALARM", timedGet); // bekannter Verlust, siehe ADR-0017
+
+        // Regeln, wie Clients sie senden: INTERVAL=1, UNTIL in UTC, WKST=SU (Android/Google)
+        foreach (var rule in new[] { "FREQ=WEEKLY;INTERVAL=1;WKST=SU;UNTIL=20991231T225959Z", "FREQ=DAILY;INTERVAL=1;COUNT=5", "FREQ=MONTHLY;BYDAY=2TU;WKST=SU;COUNT=6", "FREQ=YEARLY;BYMONTH=5;BYMONTHDAY=3" })
+        {
+            var uid = Guid.NewGuid().ToString("D");
+            var put = await PutAsync(dav, ResourcePath(calendarId, uid), Wrap(Vevent(uid, "Serie", day.AddHours(18), $"RRULE:{rule}\r\n")));
+            Assert.True(put.Response.StatusCode == HttpStatusCode.Created, $"{rule}: {(int)put.Response.StatusCode} {put.Body}");
+        }
+    }
+
     private static int CountOf(string text, string needle) => (text.Length - text.Replace(needle, string.Empty, StringComparison.Ordinal).Length) / needle.Length;
 
     [Fact]
@@ -431,6 +494,8 @@ public sealed class CalDavTests(AppFixture fixture)
 
         // Info + Liste: nie das Geheimnis im Klartext, Anzeige nur mit Präfix
         var info = (await client.GetFromJsonAsync<CalDavInfoDto>("/api/caldav/info", Ct))!;
+        Assert.StartsWith("https://", info.ServerUrl); // Schema kommt über Caddy/Web/YARP bis zur Api (Voraussetzung für CalDav:RequireHttps)
+        Assert.True(info.IsSecure);
         Assert.EndsWith("/caldav/", info.ServerUrl);
         Assert.Equal(user.UserName, info.UserName);
         var listBody = await client.GetStringAsync("/api/caldav/credentials", Ct);

tests/FamilyPlanner.UnitTests/CalDav/CalDavProtocolTests.cs

@@ -441,6 +441,38 @@ public sealed class CalDavProtocolTests
         Assert.Contains("valid-calendar-data", garbage.Body);
     }
 
+    [Theory]
+    [InlineData("FREQ=WEEKLY;INTERVAL=1;WKST=SU;UNTIL=20261231T225959Z", "FREQ=WEEKLY;INTERVAL=1;UNTIL=20261231T225959Z")]
+    [InlineData("FREQ=DAILY;WKST=SU;COUNT=3", "FREQ=DAILY;COUNT=3")]
+    [InlineData("FREQ=WEEKLY;WKST=SU;BYDAY=MO,SU", "FREQ=WEEKLY;BYDAY=MO,SU")]
+    [InlineData("FREQ=WEEKLY;INTERVAL=2;WKST=SU;BYDAY=MO", "FREQ=WEEKLY;INTERVAL=2;BYDAY=MO")]
+    [InlineData("FREQ=WEEKLY;INTERVAL=2;WKST=SU;BYDAY=MO,SU", "FREQ=WEEKLY;INTERVAL=2;WKST=SU;BYDAY=MO,SU")] // ändert die Termine: bleibt stehen -> abgelehnt
+    [InlineData("FREQ=WEEKLY;WKST=MO", "FREQ=WEEKLY;WKST=MO")]
+    public void Week_start_is_dropped_only_when_it_cannot_change_the_occurrences(string input, string expected) =>
+        Assert.Equal($"RRULE:{expected}\r\n", CalDavEndpoints.NormalizeWeekStart($"RRULE:{input}\r\n"));
+
+    [Fact]
+    public void Validate_accepts_client_style_rules_with_week_start_and_rejects_changing_ones()
+    {
+        Assert.Null(Validate(Ics(Vevent("u1", "RRULE:FREQ=WEEKLY;INTERVAL=1;WKST=SU;UNTIL=20991231T225959Z\r\n")), "u1", out var master, out _));
+        Assert.Equal("FREQ=WEEKLY;UNTIL=20991231T225959Z", master!.RecurrenceRule);
+        Assert.NotNull(Validate(Ics(Vevent("u1", "RRULE:FREQ=WEEKLY;INTERVAL=2;WKST=SU;BYDAY=MO,SU\r\n")), "u1", out _, out _));
+    }
+
+    [Fact]
+    public void Validate_maps_all_day_events_with_exclusive_end_and_ignores_alarms()
+    {
+        var ics = Ics(
+            "BEGIN:VEVENT\r\nUID:u1\r\nDTSTAMP:20261001T000000Z\r\nDTSTART;VALUE=DATE:20261110\r\nDTEND;VALUE=DATE:20261113\r\nSUMMARY:Urlaub\r\n" +
+            "BEGIN:VALARM\r\nACTION:DISPLAY\r\nTRIGGER:-P1D\r\nDESCRIPTION:x\r\nEND:VALARM\r\nEND:VEVENT\r\n");
+
+        Assert.Null(Validate(ics, "u1", out var master, out _));
+
+        Assert.True(master!.IsAllDay);
+        Assert.Equal(FamilyTime.StartOfDayUtc(new DateOnly(2026, 11, 10), FamilyTime.Berlin), master.StartUtc);
+        Assert.Equal(FamilyTime.StartOfDayUtc(new DateOnly(2026, 11, 13), FamilyTime.Berlin), master.EndUtc);
+    }
+
     // ---------- Export als CalDAV-Ressource ----------
 
     [Fact]