Let a new event's length be a setting, per calendar (#54)

CHANGELOG.md

@@ -7,6 +7,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Added
+- A new event no longer always lasts an hour. **Settings → New event form →
+  Default duration** sets how long one opens, and each calendar may keep its own
+  length underneath — 8 hours for the calendar you keep work shifts in, 30
+  minutes for the one you book calls in. A calendar without its own length
+  follows the default, switching calendars mid-form re-stretches the event, and
+  setting an end time by hand keeps it. All-day events are unaffected ([#54]).
+
 ## [2.17.1] — 2026-07-30
 
 ### Added
@@ -1253,3 +1261,4 @@ automatically, with zero telemetry and no internet permission.
 [#89]: https://codeberg.org/jlmakiola/calendula/issues/89
 [#103]: https://codeberg.org/jlmakiola/calendula/issues/103
 [#69]: https://codeberg.org/jlmakiola/calendula/issues/69
+[#54]: https://codeberg.org/jlmakiola/calendula/issues/54

app/src/main/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefs.kt

@@ -457,6 +457,46 @@ class SettingsPrefs @Inject constructor(
         store.edit { it[AUTOFOCUS_EVENT_TITLE_KEY] = enabled }
     }
 
+    /**
+     * How long a new **timed** event lasts, in minutes (#54). Defaults to
+     * [DEFAULT_EVENT_DURATION] — the historical fixed hour. Per-calendar
+     * overrides in [perCalendarEventDuration] take precedence; all-day events are
+     * date-anchored and ignore it. Resolve with [resolveDefaultEventDuration].
+     */
+    val defaultEventDurationMinutes: Flow<Int> = store.data.map { prefs ->
+        (prefs[DEFAULT_EVENT_DURATION_KEY] ?: DEFAULT_EVENT_DURATION)
+            .coerceIn(MIN_EVENT_DURATION, MAX_EVENT_DURATION)
+    }
+
+    suspend fun setDefaultEventDurationMinutes(minutes: Int) {
+        store.edit {
+            it[DEFAULT_EVENT_DURATION_KEY] = minutes.coerceIn(MIN_EVENT_DURATION, MAX_EVENT_DURATION)
+        }
+    }
+
+    /**
+     * Per-calendar overrides of [defaultEventDurationMinutes], keyed by calendar
+     * id: a calendar **present** in the map gives its new events that length, one
+     * **absent** inherits the global default (there is no "no duration", so this
+     * needs no `none` sentinel). Serialised as `id=minutes;id=minutes`.
+     */
+    val perCalendarEventDuration: Flow<Map<Long, Int>> = store.data.map { prefs ->
+        parseDurationOverrides(prefs[CALENDAR_EVENT_DURATION_KEY])
+    }
+
+    /** [minutes] null drops the override, so the calendar inherits the global default. */
+    suspend fun setCalendarEventDuration(calendarId: Long, minutes: Int?) {
+        store.edit { prefs ->
+            val current = parseDurationOverrides(prefs[CALENDAR_EVENT_DURATION_KEY]).toMutableMap()
+            if (minutes == null) {
+                current.remove(calendarId)
+            } else {
+                current[calendarId] = minutes.coerceIn(MIN_EVENT_DURATION, MAX_EVENT_DURATION)
+            }
+            prefs[CALENDAR_EVENT_DURATION_KEY] = current.toStoredDurations()
+        }
+    }
+
     /**
      * Whether Calendula posts reminder notifications (v1.4). Defaults to ON —
      * for users whose only calendar app this is, reminders are essential; the
@@ -814,6 +854,15 @@ class SettingsPrefs @Inject constructor(
         internal val DRAWER_VIEW_ORDER_KEY = stringPreferencesKey("drawer_view_order")
         internal val FORM_FIELDS_KEY = stringPreferencesKey("event_form_default_fields")
         internal val AUTOFOCUS_EVENT_TITLE_KEY = booleanPreferencesKey("autofocus_event_title")
+        internal val DEFAULT_EVENT_DURATION_KEY = intPreferencesKey("default_event_duration_minutes")
+        internal val CALENDAR_EVENT_DURATION_KEY =
+            stringPreferencesKey("per_calendar_event_duration")
+
+        /** A new timed event's length until the user changes it: one hour. */
+        const val DEFAULT_EVENT_DURATION = 60
+        internal const val MIN_EVENT_DURATION = 1
+        /** A day — past that the form is describing a multi-day event, not a default. */
+        internal const val MAX_EVENT_DURATION = 1_440
         internal val REMINDERS_ENABLED_KEY = booleanPreferencesKey("reminders_enabled")
         internal val REMINDER_ONBOARDING_KEY = booleanPreferencesKey("reminder_onboarding_done")
         internal val ALLOW_COLOR_UNSUPPORTED_KEY =
@@ -905,6 +954,17 @@ fun resolveDefaultReminder(
     }
 }
 
+/**
+ * The length a new timed event on [calendarId] opens with: that calendar's
+ * override if it has one, otherwise the [global] default. Pure so it can be
+ * unit-tested.
+ */
+fun resolveDefaultEventDuration(
+    global: Int,
+    overrides: Map<Long, Int>,
+    calendarId: Long?,
+): Int = calendarId?.let { overrides[it] } ?: global
+
 /** Sentinel stored for [WeekStartPref.Auto]; days store their [DayOfWeek.name]. */
 private const val WEEK_START_AUTO = "AUTO"
 
@@ -952,6 +1012,27 @@ private fun String?.toReminderList(): List<Int> = when {
 private fun List<Int>.toStoredReminders(): String =
     if (isEmpty()) NONE else normalizeReminders().joinToString(LIST_SEP) { it.toString() }
 
+/**
+ * Parse the per-calendar duration map (`id=minutes` entries joined by `;`).
+ * Malformed entries and out-of-range lengths are dropped, so a garbled value
+ * degrades to "inherits the global default" instead of throwing.
+ */
+private fun parseDurationOverrides(stored: String?): Map<Long, Int> =
+    stored?.split(ENTRY_SEP).orEmpty().mapNotNull { entry ->
+        val parts = entry.split(KEY_VALUE_SEP)
+        if (parts.size != 2) return@mapNotNull null
+        val calendarId = parts[0].trim().toLongOrNull() ?: return@mapNotNull null
+        val minutes = parts[1].trim().toIntOrNull()
+            ?.takeIf { it in SettingsPrefs.MIN_EVENT_DURATION..SettingsPrefs.MAX_EVENT_DURATION }
+            ?: return@mapNotNull null
+        calendarId to minutes
+    }.toMap()
+
+private fun Map<Long, Int>.toStoredDurations(): String =
+    entries.sortedBy { it.key }.joinToString(ENTRY_SEP) { (id, minutes) ->
+        "$id$KEY_VALUE_SEP$minutes"
+    }
+
 
 private inline fun <reified E : Enum<E>> String?.toEnum(default: E): E =
     this?.let { stored -> enumValues<E>().firstOrNull { it.name == stored } } ?: default

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/Picker.kt

@@ -354,35 +354,63 @@ private fun CustomDaysEditor(
 }
 
 /**
- * Snooze-duration picker, full-screen and **single-select**: the [presets]
+ * Duration picker, full-screen and **single-select**: the [presets] (whole-minute
- * (whole-minute delays) each sit as a checkmark row, with a "Custom" row that
+ * lengths) each sit as a checkmark row, with a "Custom" row that expands an
- * expands an inline amount field plus a Minutes/Hours unit toggle to enter an
+ * inline amount field plus a Minutes/Hours unit toggle to enter an arbitrary
- * arbitrary delay. Mirrors [AgendaRangePicker]'s custom-expand pattern; picking
+ * one. Mirrors [AgendaRangePicker]'s custom-expand pattern; picking a preset or
- * a preset or confirming a custom value applies via [onSelect] and closes.
+ * confirming a custom value applies via [onSelect] and closes. [label] renders a
- * [label] renders a delay in minutes as a duration ("10 minutes", "1 hour") and
+ * length in minutes ("10 minutes", "1 hour") and is reused for both the rows and
- * is reused for both the rows and the custom preview.
+ * the custom preview.
+ *
+ * [inheritLabel] adds an exclusive "use the default" row on top, for the
+ * per-calendar pickers; picking it reports null. [selected] is null exactly when
+ * that row is the current choice. [description] explains the setting above the
+ * rows when it needs it.
  */
 @Composable
-fun SnoozeDurationPicker(
+fun DurationPicker(
     title: String,
     presets: List<Int>,
-    selected: Int,
+    selected: Int?,
     label: @Composable (Int) -> String,
-    onSelect: (Int) -> Unit,
+    onSelect: (Int?) -> Unit,
     onDismiss: () -> Unit,
+    description: String? = null,
+    inheritLabel: String? = null,
 ) {
-    val customSelected = selected !in presets
+    val inherits = selected == null
+    // The current choice when it isn't one of the presets — the Custom row then
+    // names it and the editor opens pre-filled with it.
+    val custom = selected?.takeIf { it !in presets }
     val rowCount = presets.size + 1 // + the custom row
 
     var customExpanded by rememberSaveable { mutableStateOf(false) }
     var amountText by rememberSaveable {
-        mutableStateOf(if (customSelected) snoozeCustomAmount(selected).toString() else "")
+        mutableStateOf(custom?.let { durationCustomAmount(it).toString() }.orEmpty())
     }
     var unit by rememberSaveable {
-        mutableStateOf(if (customSelected) snoozeCustomUnit(selected) else ReminderUnit.Minutes)
+        mutableStateOf(custom?.let { durationCustomUnit(it) } ?: ReminderUnit.Minutes)
     }
 
     FullScreenPicker(title = title, onDismiss = onDismiss, predictiveBack = true) {
+        if (description != null) PickerDescription(description)
+        if (inheritLabel != null) {
+            GroupedRow(
+                title = inheritLabel,
+                position = Position.Alone,
+                selected = inherits,
+                trailing = if (inherits) {
+                    { SelectedCheck() }
+                } else {
+                    null
+                },
+                onClick = {
+                    onSelect(null)
+                    onDismiss()
+                },
+            )
+            Spacer(Modifier.height(24.dp))
+        }
         presets.forEachIndexed { index, minute ->
             val isSelected = minute == selected
             GroupedRow(
@@ -403,10 +431,10 @@ fun SnoozeDurationPicker(
         // The Custom row connects downward into the editor card when expanded, so
         // the two read as one grouped container (the shared custom-expand pattern).
         GroupedRow(
-            title = if (customSelected) label(selected) else stringResource(R.string.event_edit_reminder_custom),
+            title = custom?.let { label(it) } ?: stringResource(R.string.event_edit_reminder_custom),
             position = if (customExpanded) Position.Top else positionOf(presets.size, rowCount),
-            selected = customSelected,
+            selected = custom != null,
-            trailing = if (customSelected) {
+            trailing = if (custom != null) {
                 { SelectedCheck() }
             } else {
                 null
@@ -418,7 +446,7 @@ fun SnoozeDurationPicker(
             enter = expandEnter(),
             exit = collapseExit(),
         ) {
-            CustomSnoozeEditor(
+            CustomDurationEditor(
                 amountText = amountText,
                 onAmountChange = { amountText = it },
                 unit = unit,
@@ -433,21 +461,21 @@ fun SnoozeDurationPicker(
     }
 }
 
-/** Whole hours if the delay divides evenly, else minutes. */
+/** Whole hours if the length divides evenly, else minutes. */
-private fun snoozeCustomUnit(minutes: Int): ReminderUnit =
+private fun durationCustomUnit(minutes: Int): ReminderUnit =
     if (minutes % ReminderUnit.Hours.minutesFactor == 0) ReminderUnit.Hours else ReminderUnit.Minutes
 
-private fun snoozeCustomAmount(minutes: Int): Int =
+private fun durationCustomAmount(minutes: Int): Int =
     if (minutes % ReminderUnit.Hours.minutesFactor == 0) minutes / ReminderUnit.Hours.minutesFactor else minutes
 
 /**
- * The expanded "Custom" snooze editor: a tonal card connected to the Custom row
+ * The expanded "Custom" duration editor: a tonal card connected to the Custom row
  * above it. A Minutes/Hours unit toggle, an amount field with a live preview of
- * the delay it resolves to, and a tonal confirm enabled only for a valid 1–999
+ * the length it resolves to, and a tonal confirm enabled only for a valid 1–999
- * amount. [onConfirm] receives the final delay in minutes.
+ * amount. [onConfirm] receives the final length in minutes.
  */
 @Composable
-private fun CustomSnoozeEditor(
+private fun CustomDurationEditor(
     amountText: String,
     onAmountChange: (String) -> Unit,
     unit: ReminderUnit,

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/ReminderFormatting.kt

@@ -37,3 +37,21 @@ fun reminderLeadTimeLabel(minutes: Int): String = when {
         pluralStringResource(R.plurals.reminder_hours, minutes / 60, minutes / 60)
     else -> pluralStringResource(R.plurals.reminder_minutes, minutes, minutes)
 }
+
+/**
+ * Humanise a plain duration — no "before": "45 minutes", "8 hours", or both
+ * parts for a mixed length ("1 hour 30 minutes"). Shared by the snooze delay and
+ * the default event duration (#54).
+ */
+@Composable
+fun durationLabel(minutes: Int): String {
+    val hours = minutes / 60
+    val rest = minutes % 60
+    val hoursLabel = pluralStringResource(R.plurals.duration_hours, hours, hours)
+    val minutesLabel = pluralStringResource(R.plurals.duration_minutes, rest, rest)
+    return when {
+        hours == 0 -> minutesLabel
+        rest == 0 -> hoursLabel
+        else -> stringResource(R.string.duration_hours_minutes, hoursLabel, minutesLabel)
+    }
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditViewModel.kt

@@ -9,6 +9,7 @@ import de.jeanlucmakiola.calendula.data.di.IoDispatcher
 import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
 import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.calendula.data.prefs.firstDayOfWeek
+import de.jeanlucmakiola.calendula.data.prefs.resolveDefaultEventDuration
 import de.jeanlucmakiola.calendula.data.prefs.resolveDefaultReminder
 import de.jeanlucmakiola.calendula.domain.AccessLevel
 import de.jeanlucmakiola.calendula.domain.Availability
@@ -51,7 +52,7 @@ import kotlinx.datetime.toInstant
 import kotlinx.datetime.toLocalDateTime
 import kotlin.coroutines.cancellation.CancellationException
 import kotlin.time.Clock
-import kotlin.time.Duration.Companion.hours
+import kotlin.time.Duration.Companion.minutes
 import kotlin.time.Instant
 import javax.inject.Inject
 
@@ -113,6 +114,9 @@ class EventEditViewModel @Inject constructor(
     // freezes the auto-applied default: switching calendars no longer overwrites
     // their choice. Reset with the form.
     private val _remindersTouched = MutableStateFlow(false)
+    // Same freeze for the default duration (#54): once the user has set an end
+    // time by hand, switching calendars no longer stretches the event.
+    private val _durationTouched = MutableStateFlow(false)
     // A one-time offer, raised when a .ics import opens, to replace the file's
     // reminders with the settings default (#49). Null while there's nothing to ask.
     private val _importReminderPrompt = MutableStateFlow<ImportReminderPrompt?>(null)
@@ -282,8 +286,10 @@ class EventEditViewModel @Inject constructor(
      * Initialise a fresh form for a new event on [date]. [startMinutes] (minutes
      * from midnight) anchors the start when the form is opened by tapping a slot
      * in the day/week grid; without it the default is the next full hour (today)
-     * or 09:00 (any other day). No-op when a form is already open, so user input
+     * or 09:00 (any other day). The event opens an hour long and is stretched to
-     * survives configuration changes; [reset] clears it when the screen closes.
+     * the configured default by [applyDefaultDuration], like the reminders.
+     * No-op when a form is already open, so user input survives configuration
+     * changes; [reset] clears it when the screen closes.
      */
     fun openNew(date: LocalDate, startMinutes: Int? = null) {
         if (_form.value != null) return
@@ -300,9 +306,11 @@ class EventEditViewModel @Inject constructor(
             }
             else -> LocalDateTime(date, LocalTime(9, 0))
         }
-        val end = (start.toInstant(zone) + 1.hours).toLocalDateTime(zone)
+        val end = (start.toInstant(zone) + SettingsPrefs.DEFAULT_EVENT_DURATION.minutes)
+            .toLocalDateTime(zone)
         _form.value = EventForm(calendarId = null, start = start, end = end)
         applyDefaultReminder()
+        applyDefaultDuration()
     }
 
     /**
@@ -358,7 +366,9 @@ class EventEditViewModel @Inject constructor(
             val form = _form.value ?: return@launch
             if (_editTarget.value != null || _remindersTouched.value) return@launch
             val reminders = defaults.resolveFor(targetId, form.isAllDay)
-            _form.value = form.copy(reminders = reminders)
+            // Write through update(): the duration default resolves in parallel,
+            // so both must compose onto the current form, not a pre-suspend copy.
+            update { it.copy(reminders = reminders) }
             // Surface the section so an auto-applied default is visible and
             // removable, even when Reminders isn't a default-shown field.
             if (reminders.isNotEmpty()) {
@@ -377,6 +387,33 @@ class EventEditViewModel @Inject constructor(
         ReminderDefaults(timed, allDay, timedOv, allDayOv)
     }.first()
 
+    /**
+     * Stretch a new timed event to the configured default length (#54) — the
+     * resolved calendar's per-calendar duration, otherwise the global default —
+     * keeping its start put. No-op while editing an existing event, on an all-day
+     * event (which is date-anchored), or once the user has set an end time by
+     * hand. [calendarId] short-circuits the resolution after a calendar switch;
+     * null resolves it as the form does.
+     */
+    private fun applyDefaultDuration(calendarId: Long? = null) {
+        if (_editTarget.value != null || _durationTouched.value) return
+        viewModelScope.launch {
+            val global = settingsPrefs.defaultEventDurationMinutes.first()
+            val overrides = settingsPrefs.perCalendarEventDuration.first()
+            val targetId = calendarId ?: resolvedCalendarId.first()
+            // Re-check after suspending: bail if the form closed or the user edited.
+            if (_editTarget.value != null || _durationTouched.value) return@launch
+            if (_form.value?.isAllDay != false) return@launch
+            val duration = resolveDefaultEventDuration(global, overrides, targetId)
+            val zone = TimeZone.currentSystemDefault()
+            update { form ->
+                form.copy(
+                    end = (form.start.toInstant(zone) + duration.minutes).toLocalDateTime(zone),
+                )
+            }
+        }
+    }
+
     /**
      * A `.ics` import respects the file's reminders, but an event opened from a
      * file often has none while the user still expects their configured default.
@@ -455,6 +492,7 @@ class EventEditViewModel @Inject constructor(
         _editTarget.value = null
         _loadFailed.value = false
         _remindersTouched.value = false
+        _durationTouched.value = false
         _importReminderPrompt.value = null
     }
 
@@ -479,6 +517,9 @@ class EventEditViewModel @Inject constructor(
         // The default reminder differs for all-day vs timed; re-apply the
         // type-appropriate default unless the user has hand-edited it (guarded).
         applyDefaultReminder()
+        // Coming back out of all-day re-applies the default length (guarded);
+        // going all-day is a no-op, since dates carry no duration.
+        applyDefaultDuration()
     }
 
     /**
@@ -500,9 +541,10 @@ class EventEditViewModel @Inject constructor(
      */
     fun setCalendar(id: Long) {
         update { it.copy(calendarId = id, colorKey = null, color = null) }
-        // A fresh event re-inherits the new calendar's default reminder unless
+        // A fresh event re-inherits the new calendar's default reminder and
-        // the user has already hand-edited it (guarded inside).
+        // length unless the user has already hand-edited them (guarded inside).
         applyDefaultReminder(id)
+        applyDefaultDuration(id)
     }
     fun setAvailability(value: Availability) = update { it.copy(availability = value) }
     fun setAccessLevel(value: AccessLevel) = update { it.copy(accessLevel = value) }
@@ -559,8 +601,18 @@ class EventEditViewModel @Inject constructor(
     /** Moving the start drags the end along, preserving the duration. */
     fun setStartDate(date: LocalDate) = moveStart { LocalDateTime(date, it.time) }
     fun setStartTime(time: LocalTime) = moveStart { LocalDateTime(it.date, time) }
-    fun setEndDate(date: LocalDate) = update { it.copy(end = LocalDateTime(date, it.end.time)) }
+
-    fun setEndTime(time: LocalTime) = update { it.copy(end = LocalDateTime(it.end.date, time)) }
+    // Setting an end by hand is the user picking a length: it freezes the
+    // default duration, so a later calendar switch keeps their span (#54).
+    fun setEndDate(date: LocalDate) {
+        _durationTouched.value = true
+        update { it.copy(end = LocalDateTime(date, it.end.time)) }
+    }
+
+    fun setEndTime(time: LocalTime) {
+        _durationTouched.value = true
+        update { it.copy(end = LocalDateTime(it.end.date, time)) }
+    }
 
     /**
      * Validate and write. Saving a dirty recurring event pauses in

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/EventFormSettings.kt

@@ -1,24 +1,38 @@
 package de.jeanlucmakiola.calendula.ui.settings
 
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.height
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.ExpandLess
+import androidx.compose.material.icons.filled.ExpandMore
 import androidx.compose.material.icons.filled.Keyboard
+import androidx.compose.material.icons.filled.Schedule
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Switch
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.domain.EventFormField
+import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
+import de.jeanlucmakiola.calendula.ui.common.DurationPicker
+import de.jeanlucmakiola.calendula.ui.common.durationLabel
 import de.jeanlucmakiola.calendula.ui.common.eventFormFieldIcon
 import de.jeanlucmakiola.calendula.ui.common.eventFormFieldLabel
 import de.jeanlucmakiola.floret.components.CollapsingScaffold
 import de.jeanlucmakiola.floret.components.GroupedRow
 import de.jeanlucmakiola.floret.components.Position
 import de.jeanlucmakiola.floret.components.positionOf
+import de.jeanlucmakiola.floret.identity.collapseExit
+import de.jeanlucmakiola.floret.identity.expandEnter
 
 /** New event form: which fields it opens with, and how it behaves. */
 @Composable
@@ -27,6 +41,13 @@ internal fun EventFormScreen(
     viewModel: SettingsViewModel,
     onBack: () -> Unit,
 ) {
+    var showDefaultDuration by remember { mutableStateOf(false) }
+    // The calendar whose duration-override picker is open, if any.
+    var durationTarget by remember { mutableStateOf<Long?>(null) }
+    var durationSectionExpanded by remember { mutableStateOf(false) }
+    // Special-dates calendars carry all-day events only, which have no length.
+    val durationCalendars = state.writableCalendars.filterNot { it.id in state.managedCalendarIds }
+
     CollapsingScaffold(
         title = stringResource(R.string.settings_section_event_form),
         onBack = onBack,
@@ -80,6 +101,64 @@ internal fun EventFormScreen(
             onClick = { viewModel.setAutofocusEventTitle(!state.autofocusEventTitle) },
         )
 
+        // How long a new timed event opens (#54), globally and per calendar —
+        // the per-calendar list folds behind its own header, like the reminders.
+        Spacer(Modifier.height(24.dp))
+        GroupedRow(
+            title = stringResource(R.string.settings_event_duration),
+            summary = durationLabel(state.defaultEventDurationMinutes),
+            position = if (durationCalendars.isEmpty()) Position.Alone else Position.Top,
+            leading = {
+                Icon(
+                    imageVector = Icons.Default.Schedule,
+                    contentDescription = null,
+                    tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            },
+            onClick = { showDefaultDuration = true },
+        )
+        if (durationCalendars.isNotEmpty()) {
+            GroupedRow(
+                title = stringResource(R.string.settings_calendar_durations_title),
+                summary = stringResource(R.string.settings_calendar_durations_hint),
+                // Expanded, the header opens the calendar run below it and the
+                // two read as one container (the shared expand pattern).
+                position = if (durationSectionExpanded) Position.Top else Position.Bottom,
+                trailing = {
+                    Icon(
+                        imageVector = if (durationSectionExpanded) Icons.Default.ExpandLess else Icons.Default.ExpandMore,
+                        contentDescription = null,
+                        tint = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                },
+                onClick = { durationSectionExpanded = !durationSectionExpanded },
+            )
+            AnimatedVisibility(
+                visible = durationSectionExpanded,
+                enter = expandEnter(),
+                exit = collapseExit(),
+            ) {
+                Column {
+                    durationCalendars.forEachIndexed { index, calendar ->
+                        val override = state.perCalendarEventDuration[calendar.id]
+                        GroupedRow(
+                            title = calendar.displayName,
+                            summary = override?.let { durationLabel(it) }
+                                ?: stringResource(
+                                    R.string.settings_calendar_duration_inherits,
+                                    durationLabel(state.defaultEventDurationMinutes),
+                                ),
+                            // The header above is the run's first row, so the
+                            // calendars continue it: middles, then its bottom.
+                            position = positionOf(index + 1, durationCalendars.size + 1),
+                            leading = { CalendarColorChip(calendar.color) },
+                            onClick = { durationTarget = calendar.id },
+                        )
+                    }
+                }
+            }
+        }
+
         // Per-event colour on calendars that publish no colour set (some
         // CalDAV); off by default, since it may not survive their next sync.
         Spacer(Modifier.height(24.dp))
@@ -100,4 +179,34 @@ internal fun EventFormScreen(
             },
         )
     }
+
+    if (showDefaultDuration) {
+        DurationPicker(
+            title = stringResource(R.string.settings_event_duration),
+            description = stringResource(R.string.settings_event_duration_hint),
+            presets = EVENT_DURATION_PRESETS,
+            selected = state.defaultEventDurationMinutes,
+            label = { durationLabel(it) },
+            // No inherit row on the global default, so a pick is never null.
+            onSelect = { minutes -> minutes?.let { viewModel.setDefaultEventDuration(it) } },
+            onDismiss = { showDefaultDuration = false },
+        )
+    }
+    durationTarget?.let { calendarId ->
+        DurationPicker(
+            title = stringResource(R.string.settings_event_duration),
+            presets = EVENT_DURATION_PRESETS,
+            selected = state.perCalendarEventDuration[calendarId],
+            label = { durationLabel(it) },
+            inheritLabel = stringResource(
+                R.string.settings_calendar_duration_use_default,
+                durationLabel(state.defaultEventDurationMinutes),
+            ),
+            onSelect = { viewModel.setCalendarEventDuration(calendarId, it) },
+            onDismiss = { durationTarget = null },
+        )
+    }
 }
+
+/** Lengths offered for a new timed event, in minutes — up to a full work day. */
+private val EVENT_DURATION_PRESETS = listOf(15, 30, 45, 60, 90, 120, 240, 480)

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/NotificationSettings.kt

@@ -28,7 +28,6 @@ import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalContext
-import androidx.compose.ui.res.pluralStringResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.dp
 import androidx.core.content.ContextCompat
@@ -38,10 +37,11 @@ import androidx.lifecycle.LifecycleEventObserver
 import androidx.lifecycle.compose.LocalLifecycleOwner
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
+import de.jeanlucmakiola.calendula.ui.common.DurationPicker
 import de.jeanlucmakiola.calendula.ui.common.REMINDER_PRESETS
 import de.jeanlucmakiola.calendula.ui.common.ReminderDefaultPicker
-import de.jeanlucmakiola.calendula.ui.common.SnoozeDurationPicker
 import de.jeanlucmakiola.calendula.ui.common.TimePickerAlert
+import de.jeanlucmakiola.calendula.ui.common.durationLabel
 import de.jeanlucmakiola.floret.components.CollapsingScaffold
 import de.jeanlucmakiola.floret.components.GroupedRow
 import de.jeanlucmakiola.floret.components.Position
@@ -146,7 +146,7 @@ internal fun NotificationsScreen(
 
         GroupedRow(
             title = stringResource(R.string.settings_snooze_duration),
-            summary = snoozeDurationLabel(state.snoozeMinutes),
+            summary = durationLabel(state.snoozeMinutes),
             position = Position.Bottom,
             onClick = { showSnooze = true },
         )
@@ -245,12 +245,13 @@ internal fun NotificationsScreen(
     }
 
     if (showSnooze) {
-        SnoozeDurationPicker(
+        DurationPicker(
             title = stringResource(R.string.settings_snooze_duration),
             presets = SNOOZE_PRESETS,
             selected = state.snoozeMinutes,
-            label = { snoozeDurationLabel(it) },
+            label = { durationLabel(it) },
-            onSelect = { viewModel.setSnoozeMinutes(it) },
+            // No inherit row here, so a pick is never null.
+            onSelect = { minutes -> minutes?.let { viewModel.setSnoozeMinutes(it) } },
             onDismiss = { showSnooze = false },
         )
     }
@@ -348,15 +349,6 @@ private fun calendarOverrideSummary(
 /** Snooze delays offered for the notification "Snooze" action, in minutes. */
 private val SNOOZE_PRESETS = listOf(5, 10, 15, 30, 60)
 
-/** A snooze delay as a plain duration ("10 minutes", "1 hour") — no "before". */
-@Composable
-private fun snoozeDurationLabel(minutes: Int): String =
-    if (minutes % 60 == 0) {
-        pluralStringResource(R.plurals.duration_hours, minutes / 60, minutes / 60)
-    } else {
-        pluralStringResource(R.plurals.duration_minutes, minutes, minutes)
-    }
-
 /**
  * Whether Calendula is exempt from battery optimisation, re-read on every
  * `ON_RESUME` so a change made in system settings shows up at once.

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsUiState.kt

@@ -63,6 +63,10 @@ data class SettingsUiState(
     val defaultFormFields: Set<EventFormField> = SettingsPrefs.DEFAULT_FORM_FIELDS,
     /** Whether the new-event form auto-focuses the title and shows the keyboard (#10). */
     val autofocusEventTitle: Boolean = true,
+    /** How long a new timed event lasts, in minutes (#54); all-day events ignore it. */
+    val defaultEventDurationMinutes: Int = SettingsPrefs.DEFAULT_EVENT_DURATION,
+    /** Per-calendar overrides of [defaultEventDurationMinutes]; absent = inherit. */
+    val perCalendarEventDuration: Map<Long, Int> = emptyMap(),
     /** Whether Calendula posts reminder notifications (v1.4). */
     val remindersEnabled: Boolean = true,
     /**

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsViewModel.kt

@@ -123,8 +123,14 @@ class SettingsViewModel @Inject constructor(
                 prefs.perCalendarAllDayReminderOverride,
                 writableCalendars,
                 prefs.managedCalendarIds,
-            ) { overrides, allDayOverrides, calendars, managedIds ->
+                // The new-event duration defaults (#54) fold into one flow so they
-                ReminderOverrides(overrides, allDayOverrides, calendars, managedIds)
+                // fit this group — the outer combine is at its five-arg limit.
+                combine(
+                    prefs.defaultEventDurationMinutes,
+                    prefs.perCalendarEventDuration,
+                ) { duration, perCalendar -> EventDurations(duration, perCalendar) },
+            ) { overrides, allDayOverrides, calendars, managedIds, durations ->
+                ReminderOverrides(overrides, allDayOverrides, calendars, managedIds, durations)
             },
             combine(
                 prefs.defaultView,
@@ -198,6 +204,8 @@ class SettingsViewModel @Inject constructor(
                 perCalendarAllDayReminderOverride = overrides.allDay,
                 writableCalendars = overrides.calendars,
                 managedCalendarIds = overrides.managedIds,
+                defaultEventDurationMinutes = overrides.durations.default,
+                perCalendarEventDuration = overrides.durations.perCalendar,
             )
         }.stateIn(
             scope = viewModelScope,
@@ -260,6 +268,12 @@ class SettingsViewModel @Inject constructor(
         val allDay: Map<Long, List<Int>>,
         val calendars: List<CalendarSource>,
         val managedIds: Set<Long>,
+        val durations: EventDurations,
+    )
+
+    private data class EventDurations(
+        val default: Int,
+        val perCalendar: Map<Long, Int>,
     )
 
     private data class ViewSettings(
@@ -600,6 +614,15 @@ class SettingsViewModel @Inject constructor(
         viewModelScope.launch { prefs.setAutofocusEventTitle(enabled) }
     }
 
+    fun setDefaultEventDuration(minutes: Int) {
+        viewModelScope.launch { prefs.setDefaultEventDurationMinutes(minutes) }
+    }
+
+    /** [minutes] null clears the override, so the calendar inherits the default. */
+    fun setCalendarEventDuration(calendarId: Long, minutes: Int?) {
+        viewModelScope.launch { prefs.setCalendarEventDuration(calendarId, minutes) }
+    }
+
     fun setDefaultReminderMinutes(minutes: List<Int>) {
         viewModelScope.launch { prefs.setDefaultReminderMinutes(minutes) }
     }

app/src/main/res/values/strings.xml

@@ -242,6 +242,8 @@
         <item quantity="one">%d day</item>
         <item quantity="other">%d days</item>
     </plurals>
+    <!-- A mixed duration: %1$s is the hours part, %2$s the minutes part. -->
+    <string name="duration_hours_minutes">%1$s %2$s</string>
     <plurals name="duration_weeks">
         <item quantity="one">%d week</item>
         <item quantity="other">%d weeks</item>
@@ -428,6 +430,14 @@
     <string name="settings_form_fields_hint">Fields shown by default — everything else sits behind \"More fields\"</string>
     <string name="settings_autofocus_title">Focus title on new event</string>
     <string name="settings_autofocus_title_hint">When you start a new event, place the cursor in the title field and open the keyboard right away.</string>
+    <string name="settings_event_duration">Default duration</string>
+    <string name="settings_event_duration_hint">How long a new event lasts until you change its end time. All-day events aren\'t affected.</string>
+    <string name="settings_calendar_durations_title">Per-calendar duration</string>
+    <string name="settings_calendar_durations_hint">Give a calendar its own default length — e.g. 8 hours for work shifts.</string>
+    <!-- Row summary for a calendar with no duration of its own. %1$s is the default length, e.g. "1 hour". -->
+    <string name="settings_calendar_duration_inherits">Default (%1$s)</string>
+    <!-- Picker row that drops a calendar\'s own length. %1$s is the default length. -->
+    <string name="settings_calendar_duration_use_default">Use default duration (%1$s)</string>
     <string name="settings_color_unsupported">Allow colors on unsupported calendars</string>
     <string name="settings_color_unsupported_hint">Some calendars (e.g. certain CalDAV) publish no color set; a custom event color may be dropped or overwritten on their next sync. That\'s a limitation of those calendars, not something Calendula can fix.</string>
     <string name="settings_section_notifications">Notifications</string>

app/src/test/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefsTest.kt

@@ -475,6 +475,56 @@ class SettingsPrefsTest {
         assertThat(prefs.snoozeMinutes.first()).isEqualTo(1)
     }
 
+    @Test
+    fun `event duration defaults to an hour and clamps to a sane span`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        val prefs = SettingsPrefs(newDataStore(tempDir))
+        assertThat(prefs.defaultEventDurationMinutes.first()).isEqualTo(60)
+        prefs.setDefaultEventDurationMinutes(480)
+        assertThat(prefs.defaultEventDurationMinutes.first()).isEqualTo(480)
+        prefs.setDefaultEventDurationMinutes(0)
+        assertThat(prefs.defaultEventDurationMinutes.first()).isEqualTo(1)
+        prefs.setDefaultEventDurationMinutes(5_000)
+        assertThat(prefs.defaultEventDurationMinutes.first()).isEqualTo(1_440)
+    }
+
+    @Test
+    fun `per-calendar duration round-trips and clears back to inherit`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        val prefs = SettingsPrefs(newDataStore(tempDir))
+        assertThat(prefs.perCalendarEventDuration.first()).isEmpty()
+        prefs.setCalendarEventDuration(7L, 480)
+        prefs.setCalendarEventDuration(9L, 30)
+        assertThat(prefs.perCalendarEventDuration.first()).containsExactly(7L, 480, 9L, 30)
+        prefs.setCalendarEventDuration(7L, null)
+        assertThat(prefs.perCalendarEventDuration.first()).containsExactly(9L, 30)
+    }
+
+    @Test
+    fun `garbage per-calendar duration entries are dropped, the rest survive`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        val store = newDataStore(tempDir)
+        val prefs = SettingsPrefs(store)
+        store.updateData { p ->
+            val m = p.toMutablePreferences()
+            // A bad id, a non-numeric length, one out of range, and a good entry.
+            m[SettingsPrefs.CALENDAR_EVENT_DURATION_KEY] = "x=60;7=soon;8=99999;9=45"
+            m
+        }
+        assertThat(prefs.perCalendarEventDuration.first()).containsExactly(9L, 45)
+    }
+
+    @Test
+    fun `resolveDefaultEventDuration prefers the calendar's own length`() {
+        val overrides = mapOf(7L to 480)
+        assertThat(resolveDefaultEventDuration(60, overrides, calendarId = 7L)).isEqualTo(480)
+        assertThat(resolveDefaultEventDuration(60, overrides, calendarId = 9L)).isEqualTo(60)
+        assertThat(resolveDefaultEventDuration(60, overrides, calendarId = null)).isEqualTo(60)
+    }
+
     @Test
     fun `custom-font stamps default to zero and bump per role independently`(@TempDir tempDir: Path) = runTest {
         val prefs = SettingsPrefs(newDataStore(tempDir))

app/src/test/java/de/jeanlucmakiola/calendula/ui/edit/EventEditViewModelTest.kt

@@ -22,6 +22,9 @@ import kotlinx.coroutines.test.resetMain
 import kotlinx.coroutines.test.runTest
 import kotlinx.coroutines.test.setMain
 import kotlinx.coroutines.Dispatchers
+import kotlinx.datetime.LocalDate
+import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.LocalTime
 import org.junit.jupiter.api.AfterEach
 import org.junit.jupiter.api.BeforeEach
 import org.junit.jupiter.api.Test
@@ -85,9 +88,11 @@ class EventEditViewModelTest {
     private fun viewModel(
         tempDir: Path,
         fake: FakeCalendarDataSource,
+        // Passed in by the tests that need to seed a setting first; a second
+        // DataStore on the same file would clash, so it is built only once.
+        s: SettingsPrefs = settings(tempDir),
     ): EventEditViewModel {
         val p = prefs(tempDir)
-        val s = settings(tempDir)
         val repo = CalendarRepositoryImpl(fake, p, s, dispatcher as CoroutineDispatcher)
         return EventEditViewModel(repo, p, s, dispatcher)
     }
@@ -200,6 +205,71 @@ class EventEditViewModelTest {
         job.cancel()
     }
 
+    @Test
+    fun `a new event takes its calendar's default duration, and follows a switch`(
+        @TempDir tempDir: Path,
+    ) = runTest(dispatcher) {
+        val fake = FakeCalendarDataSource().apply { calendarsResult = listOf(cal(1L), cal(2L)) }
+        val s = settings(tempDir)
+        s.setDefaultEventDurationMinutes(30)
+        s.setCalendarEventDuration(2L, 480)
+        val vm = viewModel(tempDir, fake, s)
+        val job = activate(vm)
+
+        vm.openNew(LocalDate(2030, 1, 15), startMinutes = 9 * 60)
+        advanceUntilIdle()
+
+        // Calendar 1 has no length of its own, so it inherits the global 30 min.
+        assertThat(vm.state.value?.form?.end).isEqualTo(LocalDateTime(2030, 1, 15, 9, 30))
+
+        vm.setCalendar(2L)
+        advanceUntilIdle()
+
+        assertThat(vm.state.value?.form?.end).isEqualTo(LocalDateTime(2030, 1, 15, 17, 0))
+        job.cancel()
+    }
+
+    @Test
+    fun `an end time set by hand survives a calendar switch`(
+        @TempDir tempDir: Path,
+    ) = runTest(dispatcher) {
+        val fake = FakeCalendarDataSource().apply { calendarsResult = listOf(cal(1L), cal(2L)) }
+        val s = settings(tempDir)
+        s.setCalendarEventDuration(2L, 480)
+        val vm = viewModel(tempDir, fake, s)
+        val job = activate(vm)
+
+        vm.openNew(LocalDate(2030, 1, 15), startMinutes = 9 * 60)
+        advanceUntilIdle()
+        vm.setEndTime(LocalTime(10, 15))
+        vm.setCalendar(2L)
+        advanceUntilIdle()
+
+        assertThat(vm.state.value?.form?.end).isEqualTo(LocalDateTime(2030, 1, 15, 10, 15))
+        job.cancel()
+    }
+
+    @Test
+    fun `an all-day event ignores the default duration`(
+        @TempDir tempDir: Path,
+    ) = runTest(dispatcher) {
+        val fake = FakeCalendarDataSource().apply { calendarsResult = listOf(cal(1L), cal(2L)) }
+        val s = settings(tempDir)
+        s.setCalendarEventDuration(2L, 480)
+        val vm = viewModel(tempDir, fake, s)
+        val job = activate(vm)
+
+        vm.openNew(LocalDate(2030, 1, 15), startMinutes = 9 * 60)
+        advanceUntilIdle()
+        vm.setAllDay(true)
+        vm.setCalendar(2L)
+        advanceUntilIdle()
+
+        // Dates carry no length: the times stay where the form put them.
+        assertThat(vm.state.value?.form?.end).isEqualTo(LocalDateTime(2030, 1, 15, 10, 0))
+        job.cancel()
+    }
+
     @Test
     fun `editing a recurring event without moving still asks for the scope`(
         @TempDir tempDir: Path,