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

@@ -2,9 +2,12 @@ package de.jeanlucmakiola.calendula.ui.agenda
 
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.FailureReason
+import kotlinx.datetime.DateTimeUnit
 import kotlinx.datetime.LocalDate
 import kotlinx.datetime.TimeZone
+import kotlinx.datetime.plus
 import kotlinx.datetime.toLocalDateTime
+import kotlin.time.Duration.Companion.milliseconds
 
 /** One calendar day with at least one event, for the agenda list. */
 data class AgendaDay(
@@ -15,22 +18,36 @@ data class AgendaDay(
 
 /**
  * Group flat [instances] into forward-looking [AgendaDay]s (only days that
- * actually carry events). An event that began before [anchor] (ongoing or
- * multi-day) is clamped to the anchor day so it still surfaces on top. Within a
- * day, all-day events sort first, then ascending by start time, then title.
+ * actually carry events). A multi-day event surfaces on *every* day it spans,
+ * not just its first — clamped to [[anchor], [windowEnd]] so an event that began
+ * before the window (ongoing) still lists from the anchor day, and one running
+ * past the window stops at the last visible day. Within a day, all-day events
+ * sort first, then ascending by start time, then title.
  *
  * Shared by the Agenda screen and the agenda home-screen widget so both group
  * and order identically.
  */
 fun groupAgendaDays(
     anchor: LocalDate,
+    windowEnd: LocalDate,
     instances: List<EventInstance>,
     zone: TimeZone,
-): List<AgendaDay> =
-    instances
-        .groupBy { it.start.toLocalDateTime(zone).date.coerceAtLeast(anchor) }
-        .toSortedMap()
-        .map { (date, dayEvents) ->
+): List<AgendaDay> {
+    val byDay = sortedMapOf<LocalDate, MutableList<EventInstance>>()
+    for (instance in instances) {
+        val firstDay = instance.start.toLocalDateTime(zone).date.coerceAtLeast(anchor)
+        // The last day the event actually occupies. An event ending exactly at
+        // midnight (all-day events end at the exclusive next-midnight) does not
+        // reach into that boundary day, so resolve the instant just before [end].
+        val lastInstant = if (instance.end > instance.start) instance.end - 1.milliseconds else instance.start
+        val lastDay = lastInstant.toLocalDateTime(zone).date.coerceAtMost(windowEnd)
+        var day = firstDay
+        while (day <= lastDay) {
+            byDay.getOrPut(day) { mutableListOf() }.add(instance)
+            day = day.plus(1, DateTimeUnit.DAY)
+        }
+    }
+    return byDay.map { (date, dayEvents) ->
         AgendaDay(
             date = date,
             events = dayEvents.sortedWith(
@@ -40,6 +57,7 @@ fun groupAgendaDays(
             ),
         )
     }
+}
 
 /**
  * Ensure [today] surfaces as the first agenda day even when it carries no

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

@@ -159,11 +159,11 @@ class AgendaViewModel @Inject constructor(
             return AgendaUiState.Failure(FailureReason.NoCalendarsConfigured)
         }
         val anchor = params.anchor
-        val days = groupAgendaDays(anchor, instances, zone)
         val rangeEnd = anchor.plus(
             params.range.dayCount(anchor, params.weekStart) - 1,
             DateTimeUnit.DAY,
         )
+        val days = groupAgendaDays(anchor, rangeEnd, instances, zone)
         return AgendaUiState.Success(
             anchor = anchor,
             today = todayDate,

app/src/main/java/de/jeanlucmakiola/calendula/widget/WidgetData.kt

@@ -131,13 +131,14 @@ internal suspend fun Context.loadAgendaWidgetData(): AgendaWidgetData {
     // the composition from Glance state, so changing the range is a plain
     // recomposition and never depends on the widget session restarting.
     val window = agendaRange(anchor, AgendaRange.MAX_CUSTOM_DAYS - 1, zone)
+    val windowEnd = anchor.plus(AgendaRange.MAX_CUSTOM_DAYS - 1, DateTimeUnit.DAY)
     val instances = ep.calendarRepository().instances(window).first()
     val is24Hour = prefs.timeFormat.first()
         .is24Hour(android.text.format.DateFormat.is24HourFormat(this))
     val soften = prefs.softenCalendarColors.first()
     return AgendaWidgetData.Ready(
         today = anchor,
-        days = groupAgendaDays(anchor, instances, zone),
+        days = groupAgendaDays(anchor, windowEnd, instances, zone),
         is24Hour = is24Hour,
         soften = soften,
         weekStart = weekStart,

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

@@ -0,0 +1,119 @@
+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 GroupAgendaDaysTest {
+
+    private val zone = TimeZone.UTC
+    private val anchor = LocalDate(2026, 7, 1)
+    // A wide window so clamping to the window end is out of the way unless tested.
+    private val windowEnd = LocalDate(2026, 7, 31)
+
+    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(
+        id: Long,
+        title: String,
+        start: Instant,
+        end: Instant,
+        isAllDay: Boolean = false,
+    ) = EventInstance(
+        instanceId = id,
+        eventId = id,
+        calendarId = 1,
+        title = title,
+        start = start,
+        end = end,
+        isAllDay = isAllDay,
+        color = 0,
+        location = null,
+    )
+
+    private fun days(instances: List<EventInstance>) =
+        groupAgendaDays(anchor, windowEnd, instances, zone)
+
+    @Test
+    fun `a timed multi-day event lists on every day it spans`() {
+        val e = event(1, "trip", at(2026, 7, 1, 14, 0), at(2026, 7, 3, 10, 0))
+
+        val result = days(listOf(e))
+
+        assertThat(result.map { it.date }).containsExactly(
+            LocalDate(2026, 7, 1),
+            LocalDate(2026, 7, 2),
+            LocalDate(2026, 7, 3),
+        ).inOrder()
+        result.forEach { assertThat(it.events).containsExactly(e) }
+    }
+
+    @Test
+    fun `an all-day multi-day event stops before its exclusive next-midnight end`() {
+        // 1–3 July inclusive: end is the exclusive midnight opening 4 July.
+        val e = event(1, "holiday", at(2026, 7, 1), at(2026, 7, 4), isAllDay = true)
+
+        val result = days(listOf(e))
+
+        assertThat(result.map { it.date }).containsExactly(
+            LocalDate(2026, 7, 1),
+            LocalDate(2026, 7, 2),
+            LocalDate(2026, 7, 3),
+        ).inOrder()
+    }
+
+    @Test
+    fun `a single-day event lists exactly once`() {
+        val e = event(1, "lunch", at(2026, 7, 2, 12, 0), at(2026, 7, 2, 13, 0))
+
+        assertThat(days(listOf(e)).map { it.date })
+            .containsExactly(LocalDate(2026, 7, 2))
+    }
+
+    @Test
+    fun `an event ending exactly at midnight does not reach the next day`() {
+        val e = event(1, "late", at(2026, 7, 1, 22, 0), at(2026, 7, 2, 0, 0))
+
+        assertThat(days(listOf(e)).map { it.date })
+            .containsExactly(LocalDate(2026, 7, 1))
+    }
+
+    @Test
+    fun `an event begun before the anchor is clamped to the anchor day`() {
+        val e = event(1, "ongoing", at(2026, 6, 29, 9, 0), at(2026, 7, 2, 9, 0))
+
+        assertThat(days(listOf(e)).map { it.date }).containsExactly(
+            LocalDate(2026, 7, 1),
+            LocalDate(2026, 7, 2),
+        ).inOrder()
+    }
+
+    @Test
+    fun `an event running past the window is clamped to the last visible day`() {
+        val narrowEnd = LocalDate(2026, 7, 2)
+        val e = event(1, "long", at(2026, 7, 1, 9, 0), at(2026, 7, 5, 9, 0))
+
+        val result = groupAgendaDays(anchor, narrowEnd, listOf(e), zone)
+
+        assertThat(result.map { it.date }).containsExactly(
+            LocalDate(2026, 7, 1),
+            LocalDate(2026, 7, 2),
+        ).inOrder()
+    }
+
+    @Test
+    fun `within a day all-day events sort before timed ones`() {
+        val allDay = event(1, "birthday", at(2026, 7, 1), at(2026, 7, 2), isAllDay = true)
+        val timed = event(2, "call", at(2026, 7, 1, 9, 0), at(2026, 7, 1, 10, 0))
+
+        val dayOne = days(listOf(timed, allDay)).first { it.date == anchor }
+
+        assertThat(dayOne.events).containsExactly(allDay, timed).inOrder()
+    }
+}