fix(detail): derive series length from DURATION when DTEND is null (#48)

A recurring series row carries DURATION, not DTEND, so EventDetailMapper's
end == begin fallback rendered it zero-length. That was harmless while every
caller supplied per-occurrence times from Instances, but the bare
content://…/events/<id> VIEW intent added in #48 names no occurrence and
keeps the row's own times — so a series opened from a third-party widget
without begin/end extras showed as "10:00 – 10:00".

Read DURATION in the detail projection and derive the end from it, the same
way SearchMapper and IcsExportMapper already do.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventDetailMapper.kt

@@ -14,6 +14,7 @@ import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.EventStatus
 import de.jeanlucmakiola.calendula.domain.Reminder
 import de.jeanlucmakiola.calendula.domain.ReminderMethod
+import de.jeanlucmakiola.calendula.domain.ics.parseRfc2445DurationMillis
 import java.time.Instant
 import java.time.ZoneId
 import java.time.ZoneOffset
@@ -36,15 +37,18 @@ internal fun ColumnReader.toEventDetailCore(
     val begin = getLong(EventDetailProjection.IDX_DTSTART)
 
     // Recurring events store DURATION instead of DTEND, so the series row's
-    // DTEND is null. Keep the event (end == begin); callers that opened a
+    // DTEND is null — derive the length from DURATION (as SearchMapper and
-    // specific occurrence supply the real per-occurrence times from
+    // IcsExportMapper do). Callers that opened a specific occurrence overwrite
-    // CalendarContract.Instances. A present-but-backwards DTEND is malformed,
+    // both times with the per-occurrence values from CalendarContract.Instances;
-    // but dropping the row would make the event un-openable — the same trap as
+    // a caller that names no occurrence (a bare content://.../events/<id> VIEW
-    // the pre-1970 DTSTART bug above (issue #34): it would surface as the
+    // intent, issue #48) keeps this row's own times, so the length has to be
-    // generic error screen with no way to open the event and fix it. Clamp to a
+    // right here or the series renders zero-length. A present-but-backwards
-    // zero-length event instead (matching SearchMapper's coerceAtLeast).
+    // DTEND is malformed, but dropping the row would make the event un-openable
+    // — the same trap as the pre-1970 DTSTART bug above (issue #34): it would
+    // surface as the generic error screen with no way to open the event and fix
+    // it. Clamp to a zero-length event instead (matching SearchMapper).
     val end = if (isNull(EventDetailProjection.IDX_DTEND)) {
-        begin
+        begin + parseRfc2445DurationMillis(getString(EventDetailProjection.IDX_DURATION))
     } else {
         getLong(EventDetailProjection.IDX_DTEND).coerceAtLeast(begin)
     }

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/Projections.kt

@@ -84,6 +84,9 @@ internal object EventDetailProjection {
         CalendarContract.Events.EVENT_TIMEZONE,
         CalendarContract.Events.SELF_ATTENDEE_STATUS,
         CalendarContract.Events.EVENT_COLOR_KEY,
+        // Recurring rows carry DURATION instead of DTEND; the detail screen
+        // needs it to render a series opened without a named occurrence.
+        CalendarContract.Events.DURATION,
     )
 
     const val IDX_EVENT_ID = 0
@@ -104,6 +107,7 @@ internal object EventDetailProjection {
     const val IDX_EVENT_TIMEZONE = 15
     const val IDX_SELF_ATTENDEE_STATUS = 16
     const val IDX_EVENT_COLOR_KEY = 17
+    const val IDX_DURATION = 18
 }
 
 /**

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/EventDetailMapperTest.kt

@@ -32,6 +32,7 @@ class EventDetailMapperTest {
         accessLevel: Any? = null,
         timezone: String? = null,
         selfStatus: Any? = null,
+        duration: String? = null,
     ): MapColumnReader = MapColumnReader(
         EventDetailProjection.IDX_EVENT_ID to eventId,
         EventDetailProjection.IDX_TITLE to title,
@@ -51,6 +52,7 @@ class EventDetailMapperTest {
         EventDetailProjection.IDX_EVENT_TIMEZONE to timezone,
         EventDetailProjection.IDX_SELF_ATTENDEE_STATUS to selfStatus,
         EventDetailProjection.IDX_EVENT_COLOR_KEY to eventColorKey,
+        EventDetailProjection.IDX_DURATION to duration,
     )
 
     private fun attendeeReader(
@@ -134,12 +136,32 @@ class EventDetailMapperTest {
     fun `pre-1970 negative dtstart is kept, not dropped (issue #34)`() {
         // A yearly birthday/anniversary anchored before the epoch has a
         // legitimately negative UTC epoch-millis DTSTART; recurring rows carry
-        // no DTEND (they use DURATION), so it stays end == begin.
+        // no DTEND (they use DURATION), so the length comes from DURATION.
         val begin = -157_766_400_000L // 1965-01-01T00:00:00Z
-        val detail = detailReader(dtstart = begin, dtend = null).toDetail()
+        val detail = detailReader(dtstart = begin, dtend = null, duration = "P1D").toDetail()
         assertThat(detail).isNotNull()
         assertThat(detail!!.instance.start.toEpochMilliseconds()).isEqualTo(begin)
-        assertThat(detail.instance.end.toEpochMilliseconds()).isEqualTo(begin)
+        assertThat(detail.instance.end.toEpochMilliseconds()).isEqualTo(begin + 86_400_000L)
+    }
+
+    @Test
+    fun `absent dtend takes its length from DURATION (issue #48)`() {
+        // A recurring series row has no DTEND. Opened without a named
+        // occurrence — a bare content://…/events/<id> VIEW intent — the row's
+        // own times are what render, so DURATION has to supply the length or
+        // the event shows as zero-length (10:00–10:00).
+        val begin = 1_000_000_000L
+        val detail = detailReader(dtstart = begin, dtend = null, duration = "PT1H").toDetail()
+        assertThat(detail).isNotNull()
+        assertThat(detail!!.instance.end.toEpochMilliseconds()).isEqualTo(begin + 3_600_000L)
+    }
+
+    @Test
+    fun `absent dtend and absent DURATION stays zero-length`() {
+        val begin = 1_000_000_000L
+        val detail = detailReader(dtstart = begin, dtend = null, duration = null).toDetail()
+        assertThat(detail).isNotNull()
+        assertThat(detail!!.instance.end.toEpochMilliseconds()).isEqualTo(begin)
     }
 
     @Test