app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaScreen.kt

@@ -569,23 +569,17 @@ private fun agendaDayLabel(date: LocalDate, today: LocalDate): String {
  */
 @Composable
 private fun agendaTimeSummary(event: EventInstance, day: LocalDate): String {
-    val allDayLabel = stringResource(R.string.event_detail_all_day)
     val is24Hour = LocalUse24HourFormat.current
     val locale = currentLocale()
 
-    val time = if (event.spansMultipleDays(zone)) {
-        val isFirstDay = day <= event.spanFirstDay(zone)
-        val isLastDay = day >= event.spanLastDay(zone)
-        when {
-            event.isAllDay -> allDayLabel
-            isFirstDay -> stringResource(R.string.agenda_span_starts, formatTime(event.start, is24Hour, locale))
-            isLastDay -> stringResource(R.string.agenda_span_ends, formatTime(event.end, is24Hour, locale))
-            else -> allDayLabel // a full middle day
-        }
-    } else if (event.isAllDay) {
-        allDayLabel
-    } else {
-        "${formatTime(event.start, is24Hour, locale)} – ${formatTime(event.end, is24Hour, locale)}"
+    val time = when (val label = agendaTimeLabel(event, day, zone)) {
+        AgendaTimeLabel.AllDay -> stringResource(R.string.event_detail_all_day)
+        is AgendaTimeLabel.Starts ->
+            stringResource(R.string.agenda_span_starts, formatTime(label.start, is24Hour, locale))
+        is AgendaTimeLabel.Ends ->
+            stringResource(R.string.agenda_span_ends, formatTime(label.end, is24Hour, locale))
+        is AgendaTimeLabel.Range ->
+            "${formatTime(label.start, is24Hour, locale)} – ${formatTime(label.end, is24Hour, locale)}"
     }
 
     val location = event.location?.takeIf { it.isNotBlank() }

app/src/main/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaUiState.kt

@@ -8,6 +8,7 @@ import kotlinx.datetime.TimeZone
 import kotlinx.datetime.plus
 import kotlinx.datetime.toLocalDateTime
 import kotlin.time.Duration.Companion.milliseconds
+import kotlin.time.Instant
 
 /**
  * The zone the event's calendar dates live in. Timed events are resolved in the
@@ -36,6 +37,36 @@ fun EventInstance.spanLastDay(zone: TimeZone): LocalDate {
 fun EventInstance.spansMultipleDays(zone: TimeZone): Boolean =
     spanFirstDay(zone) != spanLastDay(zone)
 
+/**
+ * What an agenda row's time line should convey for an event on a given day —
+ * the part of a multi-day span that [day] falls in. Pure and shared so the
+ * agenda screen and the agenda widget label multi-day events identically; each
+ * surface only formats the instants into its own locale/24h string.
+ */
+sealed interface AgendaTimeLabel {
+    /** An all-day event, or a whole in-between day of a multi-day span. */
+    data object AllDay : AgendaTimeLabel
+    /** The first day of a multi-day timed event: when it begins. */
+    data class Starts(val start: Instant) : AgendaTimeLabel
+    /** The last day of a multi-day timed event: when it ends. */
+    data class Ends(val end: Instant) : AgendaTimeLabel
+    /** A single-day timed event: its start–end range. */
+    data class Range(val start: Instant, val end: Instant) : AgendaTimeLabel
+}
+
+/** The [AgendaTimeLabel] for [event] as it appears on [day], resolved in [zone]. */
+fun agendaTimeLabel(event: EventInstance, day: LocalDate, zone: TimeZone): AgendaTimeLabel {
+    if (event.isAllDay) return AgendaTimeLabel.AllDay
+    val firstDay = event.spanFirstDay(zone)
+    val lastDay = event.spanLastDay(zone)
+    return when {
+        firstDay == lastDay -> AgendaTimeLabel.Range(event.start, event.end)
+        day <= firstDay -> AgendaTimeLabel.Starts(event.start)
+        day >= lastDay -> AgendaTimeLabel.Ends(event.end)
+        else -> AgendaTimeLabel.AllDay // a full in-between day
+    }
+}
+
 /** One calendar day with at least one event, for the agenda list. */
 data class AgendaDay(
     val date: LocalDate,
@@ -63,7 +94,10 @@ fun groupAgendaDays(
     val byDay = sortedMapOf<LocalDate, MutableList<EventInstance>>()
     for (instance in instances) {
         val firstDay = instance.spanFirstDay(zone).coerceAtLeast(anchor)
-        val lastDay = instance.spanLastDay(zone).coerceAtMost(windowEnd)
+        // Never below firstDay: an instance the query returned always surfaces on
+        // at least its first visible day, even if its end resolves earlier (e.g. a
+        // zero-length or boundary instant) — otherwise the loop would drop it.
+        val lastDay = instance.spanLastDay(zone).coerceAtMost(windowEnd).coerceAtLeast(firstDay)
         var day = firstDay
         while (day <= lastDay) {
             byDay.getOrPut(day) { mutableListOf() }.add(instance)

app/src/main/java/de/jeanlucmakiola/calendula/widget/agenda/AgendaWidget.kt

@@ -49,6 +49,8 @@ import de.jeanlucmakiola.calendula.data.prefs.parsePastEventDisplay
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.hasEnded
 import de.jeanlucmakiola.calendula.ui.agenda.AgendaRange
+import de.jeanlucmakiola.calendula.ui.agenda.AgendaTimeLabel
+import de.jeanlucmakiola.calendula.ui.agenda.agendaTimeLabel
 import de.jeanlucmakiola.calendula.ui.agenda.anchorTodayIfMissing
 import de.jeanlucmakiola.calendula.ui.agenda.dayCount
 import de.jeanlucmakiola.calendula.ui.agenda.parseAgendaRange
@@ -127,7 +129,7 @@ class RefreshAgendaAction : ActionCallback {
 /** Flat row model so the [LazyColumn] can mix day headers and events. */
 private sealed interface AgendaRow {
     data class Header(val date: LocalDate, val today: LocalDate) : AgendaRow
-    data class Event(val event: EventInstance) : AgendaRow
+    data class Event(val date: LocalDate, val event: EventInstance) : AgendaRow
     /** "Nothing left today" line under an anchored, event-less today (#35). */
     data class Placeholder(val date: LocalDate) : AgendaRow
 }
@@ -185,7 +187,7 @@ private fun AgendaWidgetBody(data: AgendaWidgetData, dark: Boolean) {
                             if (day.events.isEmpty()) {
                                 add(AgendaRow.Placeholder(day.date))
                             } else {
-                                day.events.forEach { add(AgendaRow.Event(it)) }
+                                day.events.forEach { add(AgendaRow.Event(day.date, it)) }
                             }
                         }
                     }
@@ -196,6 +198,7 @@ private fun AgendaWidgetBody(data: AgendaWidgetData, dark: Boolean) {
                                 is AgendaRow.Placeholder -> PlaceholderRow(row.date)
                                 is AgendaRow.Event -> EventRow(
                                     event = row.event,
+                                    day = row.date,
                                     dark = dark,
                                     soften = data.soften,
                                     is24Hour = data.is24Hour,
@@ -312,6 +315,7 @@ private fun PlaceholderRow(date: LocalDate) {
 @Composable
 private fun EventRow(
     event: EventInstance,
+    day: LocalDate,
     dark: Boolean,
     soften: Boolean,
     is24Hour: Boolean,
@@ -357,7 +361,7 @@ private fun EventRow(
                 style = TextStyle(color = titleColor, fontSize = 14.sp),
             )
             Text(
-                text = eventTimeSummary(context, event, is24Hour),
+                text = eventTimeSummary(context, event, day, is24Hour),
                 maxLines = 1,
                 style = TextStyle(color = GlanceTheme.colors.onSurfaceVariant, fontSize = 12.sp),
             )
@@ -396,11 +400,20 @@ private fun agendaDayLabel(context: Context, date: LocalDate, today: LocalDate):
     return if (relative != null) "$relative · $formatted" else formatted
 }
 
-private fun eventTimeSummary(context: Context, event: EventInstance, is24Hour: Boolean): String {
-    val time = if (event.isAllDay) {
-        context.getString(R.string.event_detail_all_day)
-    } else {
-        "${formatTime(event.start, is24Hour)} – ${formatTime(event.end, is24Hour)}"
+private fun eventTimeSummary(
+    context: Context,
+    event: EventInstance,
+    day: LocalDate,
+    is24Hour: Boolean,
+): String {
+    val time = when (val label = agendaTimeLabel(event, day, zone())) {
+        AgendaTimeLabel.AllDay -> context.getString(R.string.event_detail_all_day)
+        is AgendaTimeLabel.Starts ->
+            context.getString(R.string.agenda_span_starts, formatTime(label.start, is24Hour))
+        is AgendaTimeLabel.Ends ->
+            context.getString(R.string.agenda_span_ends, formatTime(label.end, is24Hour))
+        is AgendaTimeLabel.Range ->
+            "${formatTime(label.start, is24Hour)} – ${formatTime(label.end, is24Hour)}"
     }
     val location = event.location?.takeIf { it.isNotBlank() }
     return if (location != null) "$time · $location" else time

app/src/test/java/de/jeanlucmakiola/calendula/ui/agenda/AgendaTimeLabelTest.kt

@@ -0,0 +1,76 @@
+package de.jeanlucmakiola.calendula.ui.agenda
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.EventInstance
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toInstant
+import kotlin.time.Instant
+import org.junit.jupiter.api.Test
+
+class AgendaTimeLabelTest {
+
+    private val zone = TimeZone.UTC
+
+    private fun at(y: Int, mo: Int, d: Int, h: Int = 0, min: Int = 0): Instant =
+        LocalDateTime(y, mo, d, h, min).toInstant(zone)
+
+    private fun event(start: Instant, end: Instant, isAllDay: Boolean = false) = EventInstance(
+        instanceId = 1,
+        eventId = 1,
+        calendarId = 1,
+        title = "e",
+        start = start,
+        end = end,
+        isAllDay = isAllDay,
+        color = 0,
+        location = null,
+    )
+
+    private fun labelOn(y: Int, mo: Int, d: Int, event: EventInstance) =
+        agendaTimeLabel(event, LocalDate(y, mo, d), zone)
+
+    @Test
+    fun `a single-day timed event is a start-end range`() {
+        val e = event(at(2026, 7, 2, 12, 0), at(2026, 7, 2, 13, 0))
+
+        assertThat(labelOn(2026, 7, 2, e))
+            .isEqualTo(AgendaTimeLabel.Range(e.start, e.end))
+    }
+
+    @Test
+    fun `a single-day all-day event is all-day`() {
+        val e = event(at(2026, 7, 2), at(2026, 7, 3), isAllDay = true)
+
+        assertThat(labelOn(2026, 7, 2, e)).isEqualTo(AgendaTimeLabel.AllDay)
+    }
+
+    @Test
+    fun `a multi-day timed event names the start, middle, and end days`() {
+        val e = event(at(2026, 7, 1, 14, 0), at(2026, 7, 4, 10, 0))
+
+        assertThat(labelOn(2026, 7, 1, e)).isEqualTo(AgendaTimeLabel.Starts(e.start))
+        assertThat(labelOn(2026, 7, 2, e)).isEqualTo(AgendaTimeLabel.AllDay)
+        assertThat(labelOn(2026, 7, 3, e)).isEqualTo(AgendaTimeLabel.AllDay)
+        assertThat(labelOn(2026, 7, 4, e)).isEqualTo(AgendaTimeLabel.Ends(e.end))
+    }
+
+    @Test
+    fun `a multi-day all-day event is all-day on every day`() {
+        val e = event(at(2026, 7, 2), at(2026, 7, 5), isAllDay = true)
+
+        assertThat(labelOn(2026, 7, 2, e)).isEqualTo(AgendaTimeLabel.AllDay)
+        assertThat(labelOn(2026, 7, 3, e)).isEqualTo(AgendaTimeLabel.AllDay)
+        assertThat(labelOn(2026, 7, 4, e)).isEqualTo(AgendaTimeLabel.AllDay)
+    }
+
+    @Test
+    fun `an event begun before the shown day is not labelled as starting`() {
+        // Runs 29 Jun 09:00 → 2 Jul 09:00; on 1 Jul it is mid-span, on 2 Jul it ends.
+        val e = event(at(2026, 6, 29, 9, 0), at(2026, 7, 2, 9, 0))
+
+        assertThat(labelOn(2026, 7, 1, e)).isEqualTo(AgendaTimeLabel.AllDay)
+        assertThat(labelOn(2026, 7, 2, e)).isEqualTo(AgendaTimeLabel.Ends(e.end))
+    }
+}