feat(agenda): bottom-left pill to override the range for the session

Add a tonal pill in the agenda's bottom-left corner showing the current
range; tapping it opens the existing AgendaRangePicker as a session-only
override. The override lives in AgendaViewModel (in-memory), so it survives
view switches and rotation but resets to the saved default when the app is
relaunched. The pill fills with the primary container while an override is
active, and a hint in the picker spells out the temporary nature.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

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

@@ -2,21 +2,25 @@ package de.jeanlucmakiola.calendula.ui.agenda
 
 import androidx.compose.foundation.ExperimentalFoundationApi
 import androidx.compose.foundation.background
+import androidx.compose.foundation.clickable
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.itemsIndexed
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.DateRange
 import androidx.compose.material.icons.filled.EventAvailable
 import androidx.compose.material.icons.filled.Menu
 import androidx.compose.material.icons.filled.Search
@@ -35,7 +39,10 @@ import androidx.compose.material3.TopAppBarScrollBehavior
 import androidx.compose.material3.rememberDrawerState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
@@ -47,6 +54,8 @@ import androidx.hilt.navigation.compose.hiltViewModel
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.domain.EventInstance
+import de.jeanlucmakiola.calendula.ui.common.AgendaRangePicker
+import de.jeanlucmakiola.calendula.ui.common.agendaRangeLabel
 import de.jeanlucmakiola.calendula.ui.common.calendarAnimateItem
 import de.jeanlucmakiola.calendula.ui.common.CalendarDrawer
 import de.jeanlucmakiola.calendula.ui.common.CalendarFabColumn
@@ -91,11 +100,13 @@ fun AgendaScreen(
     val scrollBehavior = TopAppBarDefaults.pinnedScrollBehavior()
     val drawerState = rememberDrawerState(DrawerValue.Closed)
     val scope = rememberCoroutineScope()
+    var showRangePicker by remember { mutableStateOf(false) }
 
     val isOnToday = when (val s = state) {
         is AgendaUiState.Success -> s.anchor == s.today
         else -> true
     }
+    val successState = state as? AgendaUiState.Success
 
     ModalNavigationDrawer(
         drawerState = drawerState,
@@ -138,13 +149,84 @@ fun AgendaScreen(
                 )
             },
         ) { innerPadding ->
-            AgendaContent(
-                state = state,
-                onRetry = viewModel::goToToday,
-                onEventClick = onEventClick,
-                modifier = Modifier
-                    .padding(innerPadding)
-                    .fillMaxSize(),
+            Box(modifier = Modifier.fillMaxSize()) {
+                AgendaContent(
+                    state = state,
+                    onRetry = viewModel::goToToday,
+                    onEventClick = onEventClick,
+                    modifier = Modifier
+                        .padding(innerPadding)
+                        .fillMaxSize(),
+                )
+                // A bottom-left pill to peek at a different range for this
+                // session, mirroring the FAB column on the right.
+                successState?.let { s ->
+                    AgendaRangePill(
+                        range = s.range,
+                        isOverride = s.rangeIsOverride,
+                        onClick = { showRangePicker = true },
+                        modifier = Modifier
+                            .align(Alignment.BottomStart)
+                            .padding(innerPadding)
+                            .padding(16.dp),
+                    )
+                }
+            }
+        }
+    }
+
+    if (showRangePicker) {
+        AgendaRangePicker(
+            title = stringResource(R.string.settings_agenda_range),
+            description = stringResource(R.string.agenda_range_override_hint),
+            selected = successState?.range ?: AgendaRange.Month,
+            onSelect = viewModel::setRangeOverride,
+            onDismiss = { showRangePicker = false },
+        )
+    }
+}
+
+/**
+ * A compact tonal pill showing the agenda's current range. Tapping it opens the
+ * range picker as a session-only override. Filled with the primary container
+ * while an override is active, so the temporary state is obvious.
+ */
+@Composable
+private fun AgendaRangePill(
+    range: AgendaRange,
+    isOverride: Boolean,
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
+    val container = if (isOverride) {
+        MaterialTheme.colorScheme.primaryContainer
+    } else {
+        MaterialTheme.colorScheme.surfaceContainerHigh
+    }
+    val content = if (isOverride) {
+        MaterialTheme.colorScheme.onPrimaryContainer
+    } else {
+        MaterialTheme.colorScheme.onSurfaceVariant
+    }
+    Surface(
+        color = container,
+        contentColor = content,
+        shape = RoundedCornerShape(50),
+        modifier = modifier.clickable(onClick = onClick),
+    ) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier.padding(horizontal = 16.dp, vertical = 10.dp),
+        ) {
+            Icon(
+                imageVector = Icons.Filled.DateRange,
+                contentDescription = null,
+                modifier = Modifier.size(18.dp),
+            )
+            Spacer(Modifier.width(8.dp))
+            Text(
+                text = agendaRangeLabel(range),
+                style = MaterialTheme.typography.labelLarge,
             )
         }
     }

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

@@ -53,5 +53,9 @@ sealed interface AgendaUiState {
         val anchor: LocalDate,
         val today: LocalDate,
         val days: List<AgendaDay>,
+        /** The range currently in effect — the saved default or a session override. */
+        val range: AgendaRange,
+        /** True when [range] is a temporary in-view override of the saved default. */
+        val rangeIsOverride: Boolean,
     ) : AgendaUiState
 }

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

@@ -22,6 +22,7 @@ import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.datetime.DateTimeUnit
+import kotlinx.datetime.DayOfWeek
 import kotlinx.datetime.LocalDate
 import kotlinx.datetime.TimeZone
 import java.util.Locale
@@ -56,17 +57,31 @@ class AgendaViewModel @Inject constructor(
     private val _anchor = MutableStateFlow(todayDate)
     val anchor: StateFlow<LocalDate> = _anchor
 
+    // A transient, in-view override of the saved agenda range. Held in memory
+    // (not persisted), so it survives view switches and rotation within the
+    // session but resets to the saved default when the app is relaunched.
+    private val _rangeOverride = MutableStateFlow<AgendaRange?>(null)
+
     val state: StateFlow<AgendaUiState> =
-        combine(_anchor, screenRange, weekStartDay) { anchor, range, weekStart ->
-            Triple(anchor, range, weekStart)
+        combine(_anchor, screenRange, _rangeOverride, weekStartDay) { anchor, default, override, weekStart ->
+            AgendaParams(
+                anchor = anchor,
+                range = override ?: default,
+                rangeIsOverride = override != null && override != default,
+                weekStart = weekStart,
+            )
         }
-        .flatMapLatest { (anchor, range, weekStart) ->
-            val window = agendaRange(anchor, range.dayCount(anchor, weekStart) - 1, zone)
+        .flatMapLatest { params ->
+            val window = agendaRange(
+                params.anchor,
+                params.range.dayCount(params.anchor, params.weekStart) - 1,
+                zone,
+            )
             combine(
                 repository.calendars(),
                 repository.instances(window),
             ) { calendars, instances ->
-                buildState(anchor, calendars, instances)
+                buildState(params, calendars, instances)
             }
         }
         .catch { emit(AgendaUiState.Failure(FailureReason.ProviderUnavailable)) }
@@ -86,16 +101,35 @@ class AgendaViewModel @Inject constructor(
         _anchor.value = date
     }
 
+    /** Temporarily override the agenda range for this session (the bottom-left pill). */
+    fun setRangeOverride(range: AgendaRange) {
+        _rangeOverride.value = range
+    }
+
+    private data class AgendaParams(
+        val anchor: LocalDate,
+        val range: AgendaRange,
+        val rangeIsOverride: Boolean,
+        val weekStart: DayOfWeek,
+    )
+
     private fun buildState(
-        anchor: LocalDate,
+        params: AgendaParams,
         calendars: List<CalendarSource>,
         instances: List<EventInstance>,
     ): AgendaUiState {
         if (calendars.isEmpty()) {
             return AgendaUiState.Failure(FailureReason.NoCalendarsConfigured)
         }
+        val anchor = params.anchor
         val days = groupAgendaDays(anchor, instances, zone)
-        return AgendaUiState.Success(anchor = anchor, today = todayDate, days = days)
+        return AgendaUiState.Success(
+            anchor = anchor,
+            today = todayDate,
+            days = days,
+            range = params.range,
+            rangeIsOverride = params.rangeIsOverride,
+        )
     }
 }
 

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

@@ -293,6 +293,7 @@
     <string name="agenda_range_month">Nächste 30 Tage</string>
     <string name="agenda_range_custom">Benutzerdefiniert…</string>
     <string name="agenda_range_custom_hint">Tage</string>
+    <string name="agenda_range_override_hint">Nur vorübergehend — wird beim erneuten Öffnen von Calendula auf deinen gespeicherten Zeitraum zurückgesetzt.</string>
     <plurals name="agenda_range_days">
         <item quantity="one">%d Tag</item>
         <item quantity="other">%d Tage</item>

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

@@ -286,6 +286,7 @@
     <string name="agenda_range_month">Next 30 days</string>
     <string name="agenda_range_custom">Custom…</string>
     <string name="agenda_range_custom_hint">Days</string>
+    <string name="agenda_range_override_hint">Just for now — resets to your saved range when you reopen Calendula.</string>
     <plurals name="agenda_range_days">
         <item quantity="one">%d day</item>
         <item quantity="other">%d days</item>