Give Backup & restore its loading and failure states (#314)

Backup & restore built its rows straight from the calendar list. That list
starts empty, catches to empty on a provider error, and can legitimately load
with nothing exportable and nothing importable — all three rendered as a blank
page with no buttons at all.

- `BackupUiState` (Loading / Failure / Ready) on `CalendarsViewModel`, mirroring
  the `FilterUiState` pattern already used elsewhere.
- The restore row stays on screen whenever the screen shows anything at all.
  When no calendar can receive events it says so and routes to the calendar
  manager — whose row labels already explain per calendar *why* (read-only,
  managed, not synced) — instead of disappearing.
- New `FailureReason.NoImportTarget` for the case the list cannot explain on its
  own: calendars exist and are visible, but none can take an event.
- Export stays available on an all-hidden device. It reads the provider
  directly, so `calendarListFailure` on its own would have hidden a working
  action; the failure is raised only when both halves are dead.
- `LocalManageCalendars` is now provided around `BackupScreen` (it sits directly
  over the manager, so the way out is popping back).

Also adds `IcsGoogleImportTest` over a Google Calendar export fixture:
`VTIMEZONE` with `X-LIC-LOCATION`, `TZID`-qualified `DTSTART`/`EXDATE`, folded
`DESCRIPTION` and `ATTENDEE` lines, `RECURRENCE-ID` overrides as separate
`VEVENT`s, escaped commas, all-day alarms. All 13 pass against the parser
unchanged — the read side needed no fix.

**Does not close #304.** The blank screen this fixes is real and reachable, but
it needs the device to have no usable calendar at all; a working Google calendar
satisfies `isEventTarget`, so that reporter would have seen the restore row. The
actual cause there is still open — questions posted on the issue. This stands on
its own as the missing loading and failure states.

Refs #304

Co-authored-by: Jean-Luc Makiola <business@jeanlucmakiola.de>
Reviewed-on: https://codeberg.org/jlmakiola/calendula/pulls/314

app/src/main/java/de/jeanlucmakiola/calendula/domain/Models.kt

@@ -253,6 +253,13 @@ enum class FailureReason {
     PermissionRevoked,
     NoCalendarsConfigured,
     AllCalendarsHidden,
+
+    /**
+     * Calendars exist and are switched on, but none can receive an event: every
+     * one is read-only, app-managed, or not synced to this device. Distinct from
+     * [AllCalendarsHidden], which a visibility switch fixes.
+     */
+    NoImportTarget,
     ProviderUnavailable,
     EventNotFound,
     Unknown,

app/src/main/java/de/jeanlucmakiola/calendula/domain/ics/IcsParser.kt

@@ -166,14 +166,19 @@ class IcsParser(private val deviceZone: TimeZone = TimeZone.currentSystemDefault
             }
             when {
                 component != null -> {
+                    // A component whose END line never arrives ends at the next
+                    // one's BEGIN, not at that one's END: reading to the far END
+                    // would fold two events into one body, where the later
+                    // properties overwrite the earlier and one event is lost.
                     val end = indexOfEnd(lines, i + 1, component)
+                    val body = indexOfNextComponent(lines, i + 1, end)
                     parseComponent(
-                        body = lines.subList(i + 1, end),
+                        body = lines.subList(i + 1, body),
                         fileCalendarName = calendarName,
                         warnings = warnings,
                         isTask = component == "VTODO",
                     )?.let(events::add)
-                    i = end + 1
+                    i = if (body < end) body else end + 1
                 }
                 line.isBegin("VTIMEZONE") -> {
                     // Skipped wholesale; TZIDs resolve against the OS tz database.
@@ -445,6 +450,23 @@ class IcsParser(private val deviceZone: TimeZone = TimeZone.currentSystemDefault
         }
 
         /** Index of the matching `END:<component>` at/after [from], or list end. */
+        /**
+         * Where an unterminated component's body has to stop: the next top-level
+         * `VEVENT` / `VTODO` in `[from, end)`, or [end] when there is none. A
+         * nested `VALARM` is part of the body and is not a boundary.
+         */
+        fun indexOfNextComponent(lines: List<String>, from: Int, end: Int): Int {
+            var i = from
+            while (i < end) {
+                val line = parseContentLine(lines[i])
+                if (line != null && (line.isBegin("VEVENT") || line.isBegin("VTODO"))) {
+                    return i
+                }
+                i++
+            }
+            return end
+        }
+
         fun indexOfEnd(lines: List<String>, from: Int, component: String): Int {
             var i = from
             while (i < lines.size) {

app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHost.kt

@@ -197,10 +197,21 @@ fun CalendarHost(
     // is "restore a backup", not "add this one event". An externally opened .ics
     // keeps routing a single event straight into the prefilled create form.
     var importForceMany by remember { mutableStateOf(false) }
+    // Where a restore came from, so closing the import puts it back: the import
+    // overlays are declared under Backup & restore and the manager, so starting
+    // one has to close them — without this, finishing a restore drops you on the
+    // calendar and the next file means walking in through Settings again.
+    var backupAfterImport by rememberSaveable { mutableStateOf(false) }
+    var calendarsAfterImport by rememberSaveable { mutableStateOf(false) }
+    // One import run. The import VM lives in the Activity's store, so this is
+    // what tells it a *re-import of the same file* is new work and not the run
+    // it already finished; a rotation keeps the number and keeps the result.
+    var importSession by rememberSaveable { mutableStateOf(0) }
     LaunchedEffect(requestedImportUri) {
         if (requestedImportUri != null) {
             importUri = requestedImportUri
             importForceMany = false
+            importSession++
             onImportConsumed()
         }
     }
@@ -510,11 +521,28 @@ fun CalendarHost(
         importUri?.let { uri ->
             ImportScreen(
                 uri = uri,
+                session = importSession,
                 forceMany = importForceMany,
-                onClose = { importUri = null },
-                onManageCalendars = { showCalendars = true },
+                onClose = {
+                    importUri = null
+                    // Back to the surface the restore started from, ready for
+                    // the next file.
+                    showCalendars = calendarsAfterImport
+                    showBackup = backupAfterImport
+                    calendarsAfterImport = false
+                    backupAfterImport = false
+                },
+                onManageCalendars = {
+                    // The manager is where this leads, so it must not be
+                    // reopened underneath on close.
+                    calendarsAfterImport = false
+                    backupAfterImport = false
+                    showCalendars = true
+                },
                 onOpenSingle = { form ->
                     importUri = null
+                    calendarsAfterImport = false
+                    backupAfterImport = false
                     importFormSource = ImportSource.File
                     importForm = form
                 },
@@ -550,18 +578,33 @@ fun CalendarHost(
             enter = slideInHorizontally(slideSpec) { it } + fadeIn(),
             exit = slideOutHorizontally(slideSpec) { it } + fadeOut(),
         ) {
-            BackupScreen(
-                onBack = { showBackup = false },
-                // Restore runs the normal .ics import, and both this screen and
-                // the manager that can have opened it are declared above the
-                // import overlays — so both have to step aside.
-                onImport = {
-                    importUri = it
-                    importForceMany = true
+            // Settings can open this screen without the manager underneath, so
+            // its failure states' "Manage calendars" way out has to open the
+            // manager rather than just pop — popping alone lands on Settings
+            // (#304). Coming from the manager the flag is already set, so this
+            // is the same pop-back there.
+            CompositionLocalProvider(
+                LocalManageCalendars provides {
+                    showCalendars = true
                     showBackup = false
-                    showCalendars = false
                 },
-            )
+            ) {
+                BackupScreen(
+                    onBack = { showBackup = false },
+                    // Restore runs the normal .ics import, and both this screen
+                    // and the manager that can have opened it are declared above
+                    // the import overlays — so both have to step aside.
+                    onImport = {
+                        importUri = it
+                        importForceMany = true
+                        importSession++
+                        backupAfterImport = true
+                        calendarsAfterImport = showCalendars
+                        showBackup = false
+                        showCalendars = false
+                    },
+                )
+            }
         }
     }
 }

app/src/main/java/de/jeanlucmakiola/calendula/ui/calendars/BackupScreen.kt

@@ -4,9 +4,11 @@ import android.net.Uri
 import android.text.format.DateUtils
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 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
@@ -18,6 +20,7 @@ import androidx.compose.material.icons.filled.Schedule
 import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Button
 import androidx.compose.material3.Checkbox
+import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.SnackbarHost
 import androidx.compose.material3.SnackbarHostState
@@ -47,9 +50,10 @@ import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.data.prefs.BackupStatus
 import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.calendula.domain.CalendarSource
-import de.jeanlucmakiola.calendula.domain.isEventTarget
 import de.jeanlucmakiola.calendula.ui.common.CalendarColorChip
+import de.jeanlucmakiola.calendula.ui.common.CalendarFailure
 import de.jeanlucmakiola.calendula.ui.common.LeadingAvatar
+import de.jeanlucmakiola.calendula.ui.common.LocalManageCalendars
 import de.jeanlucmakiola.floret.components.CollapsingScaffold
 import de.jeanlucmakiola.floret.components.DialogAmountField
 import de.jeanlucmakiola.floret.components.DialogUnitDropdown
@@ -80,18 +84,13 @@ fun BackupScreen(
     onImport: (Uri) -> Unit,
     viewModel: CalendarsViewModel = hiltViewModel(),
 ) {
-    val calendars by viewModel.calendars.collectAsStateWithLifecycle()
+    val state by viewModel.backupState.collectAsStateWithLifecycle()
     val backupResult by viewModel.backupResult.collectAsStateWithLifecycle()
     val autoBackup by viewModel.autoBackup.collectAsStateWithLifecycle()
 
     val context = LocalContext.current
     val snackbarHostState = remember { SnackbarHostState() }
 
-    // Export covers local calendars only; managed special-dates mirrors are
-    // rebuilt from contacts. Restore can target anything the import picker offers.
-    val exportable = calendars.filter { it.isLocal && it.canModifyContents && !it.isManaged }
-    val canImport = calendars.any { it.isEventTarget }
-
     // Exports everything eligible (null); the per-calendar selector owns its
     // own launcher.
     val createBackup = rememberLauncherForActivityResult(
@@ -132,78 +131,42 @@ fun BackupScreen(
     CollapsingScaffold(
         title = stringResource(R.string.settings_section_backup),
         onBack = onBack,
+        // Loading and failure fill the screen and centre themselves, which they
+        // can only do in an unscrolled column — the scrolling one measures them
+        // against an unbounded height and leaves them hanging under the header.
+        scrollable = state is BackupUiState.Ready,
         snackbarHost = { SnackbarHost(snackbarHostState) },
         predictiveBack = true,
     ) {
-        HintText(stringResource(R.string.calendars_backup_hint))
-
-        if (exportable.isNotEmpty()) {
-            GroupedRow(
-                title = stringResource(R.string.calendars_backup_action),
-                position = Position.Top,
-                leading = { LeadingAvatar(Icons.Default.FileDownload) },
-                onClick = {
-                    // A single exportable calendar skips the selector.
-                    if (exportable.size == 1) {
-                        runCatching { createBackup.launch("calendula-backup-${LocalDate.now()}.ics") }
-                    } else {
-                        showExportPicker = true
-                    }
+        when (val s = state) {
+            BackupUiState.Loading -> BackupLoading()
+            is BackupUiState.Failure -> CalendarFailure(reason = s.reason, onRetry = onBack)
+            is BackupUiState.Ready -> BackupContent(
+                exportable = s.exportable,
+                canImport = s.canImport,
+                autoBackup = autoBackup,
+                viewModel = viewModel,
+                onRestore = { runCatching { openBackup.launch(RESTORE_MIME_TYPES) } },
+                onPickFolder = { runCatching { pickFolder.launch(null) } },
+                onExportAll = {
+                    runCatching { createBackup.launch(defaultBackupName()) }
                 },
-            )
-            GroupedRow(
-                title = stringResource(R.string.calendars_restore_action),
-                summary = stringResource(R.string.calendars_restore_hint),
-                position = Position.Middle,
-                leading = { LeadingAvatar(Icons.Default.FileUpload) },
-                onClick = { runCatching { openBackup.launch(RESTORE_MIME_TYPES) } },
-            )
-            GroupedRow(
-                title = stringResource(R.string.calendars_auto_backup),
-                summary = stringResource(R.string.calendars_auto_backup_hint),
-                position = if (autoBackup.enabled) Position.Middle else Position.Bottom,
-                leading = { LeadingAvatar(Icons.Default.Schedule) },
-                trailing = {
-                    Switch(checked = autoBackup.enabled, onCheckedChange = viewModel::setAutoBackupEnabled)
-                },
-                onClick = { viewModel.setAutoBackupEnabled(!autoBackup.enabled) },
-            )
-            if (autoBackup.enabled) {
-                GroupedRow(
-                    title = stringResource(R.string.calendars_auto_backup_folder),
-                    summary = rememberFolderName(autoBackup.folderUri)
-                        ?: stringResource(R.string.calendars_auto_backup_folder_unset),
-                    position = Position.Middle,
-                    onClick = { runCatching { pickFolder.launch(null) } },
-                )
-                GroupedRow(
-                    title = stringResource(R.string.calendars_auto_backup_interval),
-                    summary = backupIntervalLabel(autoBackup.intervalMinutes),
-                    position = Position.Bottom,
-                    onClick = { showInterval = true },
-                )
-                HintText(backupStatusText(autoBackup.status))
-            }
-        } else if (canImport) {
-            // Nothing to back up, but restore is still possible — don't hide
-            // it behind export eligibility.
-            SectionHeader(stringResource(R.string.calendars_restore_header))
-            HintText(stringResource(R.string.calendars_restore_hint))
-            GroupedRow(
-                title = stringResource(R.string.calendars_restore_action),
-                position = Position.Alone,
-                leading = { LeadingAvatar(Icons.Default.FileUpload) },
-                onClick = { runCatching { openBackup.launch(RESTORE_MIME_TYPES) } },
+                onExportPick = { showExportPicker = true },
+                onEditInterval = { showInterval = true },
             )
         }
     }
 
-    if (showExportPicker) {
-        ExportCalendarPicker(
-            calendars = exportable,
-            onExport = viewModel::exportBackup,
-            onDismiss = { showExportPicker = false },
-        )
+    // Gated on Ready rather than resetting the flag when the state leaves it:
+    // flipping it here would be a write during composition.
+    (state as? BackupUiState.Ready)?.let { ready ->
+        if (showExportPicker) {
+            ExportCalendarPicker(
+                calendars = ready.exportable,
+                onExport = viewModel::exportBackup,
+                onDismiss = { showExportPicker = false },
+            )
+        }
     }
     if (showInterval) {
         BackupIntervalDialog(
@@ -214,6 +177,103 @@ fun BackupScreen(
     }
 }
 
+/** The screen's loading state, centred in the scaffold's content column. */
+@Composable
+private fun BackupLoading() {
+    Box(
+        modifier = Modifier.fillMaxSize(),
+        contentAlignment = Alignment.Center,
+    ) {
+        CircularProgressIndicator()
+    }
+}
+
+/** Default file name for a one-shot export. */
+private fun defaultBackupName(): String = "calendula-backup-${LocalDate.now()}.ics"
+
+/**
+ * The working screen: export (when there are local calendars to export), restore,
+ * and the automatic-backup block. Restore is always on screen — when nothing can
+ * receive the events it says so and routes to the calendar manager rather than
+ * disappearing, which is what #304 reported as an invisible button.
+ */
+@Composable
+private fun BackupContent(
+    exportable: List<CalendarSource>,
+    canImport: Boolean,
+    autoBackup: AutoBackupUiState,
+    viewModel: CalendarsViewModel,
+    onRestore: () -> Unit,
+    onPickFolder: () -> Unit,
+    onExportAll: () -> Unit,
+    onExportPick: () -> Unit,
+    onEditInterval: () -> Unit,
+) {
+    val manageCalendars = LocalManageCalendars.current
+    // Restore never depends on export eligibility, and never disappears: when no
+    // calendar can receive events it explains that and offers the way to fix it.
+    val restoreSummary = if (canImport) {
+        stringResource(R.string.calendars_restore_hint)
+    } else {
+        stringResource(R.string.calendars_restore_unavailable)
+    }
+    val onRestoreClick = if (canImport) onRestore else (manageCalendars ?: onRestore)
+
+    if (exportable.isEmpty()) {
+        SectionHeader(stringResource(R.string.calendars_restore_header))
+        HintText(restoreSummary)
+        GroupedRow(
+            title = stringResource(R.string.calendars_restore_action),
+            position = Position.Alone,
+            leading = { LeadingAvatar(Icons.Default.FileUpload) },
+            onClick = onRestoreClick,
+        )
+        return
+    }
+
+    HintText(stringResource(R.string.calendars_backup_hint))
+    GroupedRow(
+        title = stringResource(R.string.calendars_backup_action),
+        position = Position.Top,
+        leading = { LeadingAvatar(Icons.Default.FileDownload) },
+        // A single exportable calendar skips the selector.
+        onClick = if (exportable.size == 1) onExportAll else onExportPick,
+    )
+    GroupedRow(
+        title = stringResource(R.string.calendars_restore_action),
+        summary = restoreSummary,
+        position = Position.Middle,
+        leading = { LeadingAvatar(Icons.Default.FileUpload) },
+        onClick = onRestoreClick,
+    )
+    GroupedRow(
+        title = stringResource(R.string.calendars_auto_backup),
+        summary = stringResource(R.string.calendars_auto_backup_hint),
+        position = if (autoBackup.enabled) Position.Middle else Position.Bottom,
+        leading = { LeadingAvatar(Icons.Default.Schedule) },
+        trailing = {
+            Switch(checked = autoBackup.enabled, onCheckedChange = viewModel::setAutoBackupEnabled)
+        },
+        onClick = { viewModel.setAutoBackupEnabled(!autoBackup.enabled) },
+    )
+    if (autoBackup.enabled) {
+        GroupedRow(
+            title = stringResource(R.string.calendars_auto_backup_folder),
+            summary = rememberFolderName(autoBackup.folderUri)
+                ?: stringResource(R.string.calendars_auto_backup_folder_unset),
+            position = Position.Middle,
+            onClick = onPickFolder,
+        )
+        GroupedRow(
+            title = stringResource(R.string.calendars_auto_backup_interval),
+            summary = backupIntervalLabel(autoBackup.intervalMinutes),
+            position = Position.Bottom,
+            onClick = onEditInterval,
+        )
+        HintText(backupStatusText(autoBackup.status))
+    }
+}
+
 /**
  * Choose which local calendars to include in a one-time `.ics` export. Defaults
  * to all selected; the Export action opens the SAF save dialog and hands back

app/src/main/java/de/jeanlucmakiola/calendula/ui/calendars/BackupUiState.kt

@@ -0,0 +1,53 @@
+package de.jeanlucmakiola.calendula.ui.calendars
+
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import de.jeanlucmakiola.calendula.domain.calendarListFailure
+import de.jeanlucmakiola.calendula.domain.isEventTarget
+
+/**
+ * State of the Backup & restore screen (#69). Three states, because the calendar
+ * list it is derived from has all three: it arrives empty, it can throw, and
+ * "loaded but nothing to offer" is a real outcome the screen used to render as a
+ * blank page (#304).
+ */
+sealed interface BackupUiState {
+    data object Loading : BackupUiState
+    data class Failure(val reason: FailureReason) : BackupUiState
+
+    /**
+     * At least one half of the screen works. [exportable] may be empty (restore
+     * only) and [canImport] may be false (export only), but never both — that is
+     * a [Failure].
+     */
+    data class Ready(
+        val exportable: List<CalendarSource>,
+        val canImport: Boolean,
+    ) : BackupUiState
+}
+
+/**
+ * What the screen can offer for this calendar list.
+ *
+ * Export covers the app's own local calendars; managed special-dates mirrors are
+ * rebuilt from contacts, so they are excluded. Restore can target anything the
+ * import picker offers ([isEventTarget]).
+ *
+ * A failure is raised only when *neither* is possible — deliberately not
+ * [calendarListFailure] on its own, which would call an all-hidden device a
+ * failure while its local calendars are still perfectly exportable. When both
+ * halves are dead the list itself usually says why (no calendars, everything
+ * switched off); [FailureReason.NoImportTarget] covers the remaining case, where
+ * calendars exist and are visible but every one of them is read-only, managed or
+ * not synced to the device.
+ */
+fun backupUiState(calendars: List<CalendarSource>): BackupUiState {
+    val exportable = calendars.filter { it.isLocal && it.canModifyContents && !it.isManaged }
+    val canImport = calendars.any { it.isEventTarget }
+    if (exportable.isEmpty() && !canImport) {
+        return BackupUiState.Failure(
+            calendarListFailure(calendars) ?: FailureReason.NoImportTarget,
+        )
+    }
+    return BackupUiState.Ready(exportable = exportable, canImport = canImport)
+}

app/src/main/java/de/jeanlucmakiola/calendula/ui/calendars/CalendarsViewModel.kt

@@ -14,6 +14,7 @@ import de.jeanlucmakiola.calendula.data.ics.IcsExporter
 import de.jeanlucmakiola.calendula.data.prefs.BackupStatus
 import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.FailureReason
 import de.jeanlucmakiola.calendula.domain.ics.IcsWriter
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.flow.MutableStateFlow
@@ -24,6 +25,7 @@ import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.flow.flowOn
+import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
@@ -56,6 +58,22 @@ class CalendarsViewModel @Inject constructor(
                 initialValue = emptyList(),
             )
 
+    /**
+     * The Backup & restore screen's own view of that list, with the loading and
+     * failure states [calendars] flattens away — it starts empty and catches to
+     * empty, which that screen used to render as a blank page (#304).
+     */
+    val backupState: StateFlow<BackupUiState> =
+        repository.calendars()
+            .map { backupUiState(it) }
+            .catch { emit(BackupUiState.Failure(FailureReason.ProviderUnavailable)) }
+            .flowOn(io)
+            .stateIn(
+                scope = viewModelScope,
+                started = SharingStarted.WhileSubscribed(5_000L),
+                initialValue = BackupUiState.Loading,
+            )
+
     /** Automatic-backup settings + last-run status, for the Backup section UI. */
     val autoBackup: StateFlow<AutoBackupUiState> = combine(
         settingsPrefs.autoBackupEnabled,

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

@@ -4,19 +4,36 @@ import android.content.Context
 import android.content.Intent
 import android.provider.CalendarContract
 import android.provider.Settings
+import androidx.annotation.StringRes
+import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.widthIn
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.outlined.CalendarMonth
+import androidx.compose.material.icons.outlined.EditOff
+import androidx.compose.material.icons.outlined.ErrorOutline
+import androidx.compose.material.icons.outlined.EventBusy
+import androidx.compose.material.icons.outlined.Lock
+import androidx.compose.material.icons.outlined.SyncProblem
+import androidx.compose.material.icons.outlined.VisibilityOff
 import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.compositionLocalOf
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.style.TextAlign
@@ -26,52 +43,150 @@ import de.jeanlucmakiola.calendula.domain.FailureReason
 
 /**
  * Full-screen failure state shared by every calendar screen (spec §7).
- * One explanation line + one recovery action, never a toast.
+ * A tonal icon, one headline, one supporting line and one recovery action —
+ * never a toast.
  */
 @Composable
-fun CalendarFailure(reason: FailureReason, onRetry: () -> Unit) {
+fun CalendarFailure(
+    reason: FailureReason,
+    onRetry: () -> Unit,
+    modifier: Modifier = Modifier,
+) {
     val context = LocalContext.current
     val manageCalendars = LocalManageCalendars.current
-    val titleRes = when (reason) {
-        FailureReason.PermissionRevoked -> R.string.state_failure_permission
-        FailureReason.NoCalendarsConfigured -> R.string.state_failure_no_calendars
-        FailureReason.AllCalendarsHidden -> R.string.state_failure_all_hidden
-        FailureReason.ProviderUnavailable -> R.string.state_failure_provider
-        FailureReason.Unknown,
-        FailureReason.EventNotFound -> R.string.state_failure_unknown
-    }
-    val actionRes = when (reason) {
-        FailureReason.NoCalendarsConfigured -> R.string.state_failure_no_calendars_action
-        FailureReason.AllCalendarsHidden -> R.string.state_failure_all_hidden_action
-        FailureReason.PermissionRevoked -> R.string.state_failure_permission_action
-        else -> R.string.state_retry
-    }
+    val copy = failureCopy(reason)
     val onAction: () -> Unit = when (reason) {
         FailureReason.NoCalendarsConfigured -> {
             { context.startCalendarSetup() }
         }
-        FailureReason.AllCalendarsHidden -> manageCalendars ?: onRetry
+        FailureReason.AllCalendarsHidden,
+        FailureReason.NoImportTarget,
+        -> manageCalendars ?: onRetry
         else -> onRetry
     }
     Column(
-        modifier = Modifier
+        modifier = modifier
             .fillMaxSize()
-            .padding(32.dp),
+            .padding(horizontal = 32.dp, vertical = 24.dp),
         verticalArrangement = Arrangement.Center,
         horizontalAlignment = Alignment.CenterHorizontally,
     ) {
+        FailureIcon(icon = copy.icon, isError = copy.isError)
+        Spacer(Modifier.height(24.dp))
         Text(
-            text = stringResource(titleRes),
+            text = stringResource(copy.title),
             style = MaterialTheme.typography.headlineSmall,
             textAlign = TextAlign.Center,
+            modifier = Modifier.widthIn(max = TEXT_MAX_WIDTH),
         )
-        Spacer(Modifier.height(24.dp))
+        copy.body?.let { body ->
+            Spacer(Modifier.height(12.dp))
+            Text(
+                text = stringResource(body),
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                textAlign = TextAlign.Center,
+                modifier = Modifier.widthIn(max = TEXT_MAX_WIDTH),
+            )
+        }
+        Spacer(Modifier.height(32.dp))
         FilledTonalButton(onClick = onAction) {
-            Text(stringResource(actionRes))
+            Text(stringResource(copy.action))
         }
     }
 }
 
+/** The state's mark: the reason's icon in a tonal circle above the headline. */
+@Composable
+private fun FailureIcon(icon: ImageVector, isError: Boolean) {
+    val container: Color
+    val content: Color
+    if (isError) {
+        container = MaterialTheme.colorScheme.errorContainer
+        content = MaterialTheme.colorScheme.onErrorContainer
+    } else {
+        container = MaterialTheme.colorScheme.secondaryContainer
+        content = MaterialTheme.colorScheme.onSecondaryContainer
+    }
+    Box(
+        modifier = Modifier
+            .size(72.dp)
+            .background(container, CircleShape),
+        contentAlignment = Alignment.Center,
+    ) {
+        Icon(
+            imageVector = icon,
+            contentDescription = null,
+            tint = content,
+            modifier = Modifier.size(36.dp),
+        )
+    }
+}
+
+/**
+ * What a reason says and offers. Headline and supporting line are separate so
+ * the explanation reads as body text instead of a headline that runs over three
+ * lines; [isError] tints the mark for the two reasons that are an actual fault
+ * rather than a calendar the user can switch back on.
+ */
+private data class FailureCopy(
+    val icon: ImageVector,
+    @StringRes val title: Int,
+    @StringRes val body: Int?,
+    @StringRes val action: Int,
+    val isError: Boolean = false,
+)
+
+private fun failureCopy(reason: FailureReason): FailureCopy = when (reason) {
+    FailureReason.PermissionRevoked -> FailureCopy(
+        icon = Icons.Outlined.Lock,
+        title = R.string.state_failure_permission,
+        body = R.string.state_failure_permission_body,
+        action = R.string.state_failure_permission_action,
+    )
+    FailureReason.NoCalendarsConfigured -> FailureCopy(
+        icon = Icons.Outlined.CalendarMonth,
+        title = R.string.state_failure_no_calendars,
+        body = R.string.state_failure_no_calendars_body,
+        action = R.string.state_failure_no_calendars_action,
+    )
+    FailureReason.AllCalendarsHidden -> FailureCopy(
+        icon = Icons.Outlined.VisibilityOff,
+        title = R.string.state_failure_all_hidden,
+        body = R.string.state_failure_all_hidden_body,
+        action = R.string.state_failure_all_hidden_action,
+    )
+    FailureReason.NoImportTarget -> FailureCopy(
+        icon = Icons.Outlined.EditOff,
+        title = R.string.state_failure_no_import_target,
+        body = R.string.state_failure_no_import_target_body,
+        action = R.string.state_failure_all_hidden_action,
+    )
+    FailureReason.EventNotFound -> FailureCopy(
+        icon = Icons.Outlined.EventBusy,
+        title = R.string.state_failure_event_not_found,
+        body = R.string.state_failure_event_not_found_body,
+        action = R.string.state_retry,
+    )
+    FailureReason.ProviderUnavailable -> FailureCopy(
+        icon = Icons.Outlined.SyncProblem,
+        title = R.string.state_failure_provider,
+        body = R.string.state_failure_provider_body,
+        action = R.string.state_retry,
+        isError = true,
+    )
+    FailureReason.Unknown -> FailureCopy(
+        icon = Icons.Outlined.ErrorOutline,
+        title = R.string.state_failure_unknown,
+        body = null,
+        action = R.string.state_retry,
+        isError = true,
+    )
+}
+
+/** Keeps the headline and its supporting line at a readable measure. */
+private val TEXT_MAX_WIDTH = 320.dp
+
 /**
  * Opens Settings → Calendars, the only screen that can switch a calendar back
  * on. Null outside the calendar host — screens without it never raise the

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

@@ -19,7 +19,6 @@ import androidx.compose.ui.input.pointer.PointerEventPass
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.unit.Dp
 import kotlin.math.abs
-import kotlin.math.ceil
 import kotlin.math.floor
 import kotlin.math.roundToInt
 
@@ -197,18 +196,26 @@ fun rememberTimelinePinchZoom(
  * names, jumping the whole column as a pinch drifts across each half pixel.
  * Pinning the hour to whole pixels keeps every part of the timeline on one grid.
  *
- * The bounds themselves are pulled onto that grid too, each in the direction
- * that keeps its own promise — up for the fill floor, so no dead space opens
- * under midnight, down for the ceiling. A fractional bound would be a height the
- * pinch can be held against but never actually land on, and the difference feeds
- * the focal anchor a scroll correction on every frame the fingers sit still.
+ * The ceiling is pulled onto that grid too, downwards, so it stays a height the
+ * pinch can actually land on.
+ *
+ * [fillPx] is deliberately *not* rounded (#290). It is the one height the whole
+ * day exactly fills the viewport at, and it is the same value
+ * [TimelineScale.FitDay] resolves to — rounding it up by the fraction of a pixel
+ * that 24 hours don't divide the viewport into leaves the timeline a pixel per
+ * hour taller than its own viewport, so a pinched-all-the-way-out day still
+ * scrolls a hair and bounces off Android's overscroll stretch, while the
+ * identical FitDay preset sits still. Being the clamp result rather than a bound
+ * the gesture is merely held against, it is a height the pinch does land on: the
+ * next frame reads it back unchanged and the focal anchor is handed nothing to
+ * correct.
  */
 internal fun pinchedHourHeightPx(target: Float, fillPx: Float, maxPx: Float): Float =
     // Filling the viewport wins over the ceiling: on a screen tall enough for
     // the two to disagree, dead space is the worse of the two failures.
     target.roundToInt().toFloat()
         .coerceAtMost(floor(maxPx))
-        .coerceAtLeast(ceil(fillPx))
+        .coerceAtLeast(fillPx)
 
 /**
  * The scroll offset that keeps the moment under [centroidY] under it after the

app/src/main/java/de/jeanlucmakiola/calendula/ui/detail/EventDetailScreen.kt

@@ -302,6 +302,7 @@ fun EventDetailScreen(
             is EventDetailUiState.Failure -> CalendarFailure(
                 reason = s.reason,
                 onRetry = viewModel::retry,
+                modifier = contentModifier,
             )
             is EventDetailUiState.Success -> EventDetailContent(s, copyField, contentModifier)
         }

app/src/main/java/de/jeanlucmakiola/calendula/ui/imports/ImportScreen.kt

@@ -73,19 +73,19 @@ import de.jeanlucmakiola.floret.identity.predictiveBack
 @Composable
 fun ImportScreen(
     uri: Uri,
+    session: Int,
     onClose: () -> Unit,
     onOpenSingle: (EventForm) -> Unit,
     forceMany: Boolean = false,
     onManageCalendars: (() -> Unit)? = null,
-    // Key the VM by the file uri. This screen has no nav backstack, so an
-    // unkeyed hiltViewModel() resolves to the Activity's store and is retained
-    // across imports — its one-shot `load` guard would then show the *previous*
-    // file's parsed state on the next import (a second restore, export→restore,
-    // etc.). Keying per uri hands each distinct file a fresh VM (fresh Loading
-    // state), while the same uri (rotation) reuses it and holds the result.
-    viewModel: ImportViewModel = hiltViewModel(key = uri.toString()),
+    viewModel: ImportViewModel = hiltViewModel(),
 ) {
-    LaunchedEffect(uri) { viewModel.load(uri, forceMany) }
+    // hiltViewModel() resolves to the Activity's store and is retained across
+    // imports, so the reload is driven by [session] rather than by a fresh VM:
+    // keying per uri looked right but handed a *re-import of the same file* the
+    // previous run's finished state, importing nothing (#304). A rotation keeps
+    // the session and so keeps the result.
+    LaunchedEffect(session) { viewModel.load(uri, forceMany, session) }
     val state by viewModel.state.collectAsStateWithLifecycle()
 
     // A single event isn't shown here — it opens the create form for review.

app/src/main/java/de/jeanlucmakiola/calendula/ui/imports/ImportViewModel.kt

@@ -16,6 +16,7 @@ import de.jeanlucmakiola.calendula.domain.ics.ParsedIcsEvent
 import de.jeanlucmakiola.calendula.domain.ics.toEventForm
 import de.jeanlucmakiola.calendula.domain.isEventTarget
 import kotlinx.coroutines.CoroutineDispatcher
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
@@ -69,18 +70,26 @@ class ImportViewModel @Inject constructor(
     private val parser = IcsParser()
     private val _state = MutableStateFlow<ImportUiState>(ImportUiState.Loading)
     val state: StateFlow<ImportUiState> = _state.asStateFlow()
-    private var started = false
+    private var loadedSession: Int? = null
+    private var loadJob: Job? = null
 
     /**
-     * Read + parse [uri] once; subsequent calls (recomposition) are ignored.
+     * Read + parse [uri] once per [session]; recomposition (and a rotation,
+     * which keeps the session) re-calls this and keeps the result. A new import
+     * of the *same* file is a new session, and has to parse and run again —
+     * keying on the uri alone showed the previous run's summary and imported
+     * nothing (#304).
+     *
      * When [forceMany] is set (an in-app restore), a single-event file still goes
      * through the bulk picker + summary rather than the prefilled create form —
      * a restore is "bring back a backup", not "add this one event".
      */
-    fun load(uri: Uri, forceMany: Boolean = false) {
-        if (started) return
-        started = true
-        viewModelScope.launch {
+    fun load(uri: Uri, forceMany: Boolean = false, session: Int = 0) {
+        if (loadedSession == session) return
+        loadedSession = session
+        loadJob?.cancel()
+        _state.value = ImportUiState.Loading
+        loadJob = viewModelScope.launch {
             val parsed = withContext(io) {
                 importer.readText(uri)?.let(parser::parse)
             }

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

@@ -11,12 +11,20 @@
     <string name="state_retry">Retry</string>
     <string name="state_failure_unknown">Something went wrong.</string>
     <string name="state_failure_permission">Calendar access is required.</string>
+    <string name="state_failure_permission_body">Calendula reads your events straight from the system calendar, so it needs calendar access to show anything.</string>
     <string name="state_failure_permission_action">Grant access</string>
     <string name="state_failure_no_calendars">No calendars configured.</string>
+    <string name="state_failure_no_calendars_body">Add a calendar account to this device and its calendars show up here.</string>
     <string name="state_failure_no_calendars_action">Open system calendar settings</string>
     <string name="state_failure_all_hidden">All your calendars are switched off.</string>
+    <string name="state_failure_all_hidden_body">Switch at least one calendar back on to see its events.</string>
     <string name="state_failure_all_hidden_action">Manage calendars</string>
+    <string name="state_failure_no_import_target">No calendar can take new events.</string>
+    <string name="state_failure_no_import_target_body">The calendars that are switched on are read-only, managed by another app, or not synced to this device. Switch on a calendar that can take events, or add a local one.</string>
+    <string name="state_failure_event_not_found">This event is no longer there.</string>
+    <string name="state_failure_event_not_found_body">It may have been deleted, or moved to a calendar that is switched off.</string>
     <string name="state_failure_provider">Could not read the calendar.</string>
+    <string name="state_failure_provider_body">The system calendar did not answer. Try again in a moment.</string>
 
     <!-- Long-press a field to copy it (#195) -->
     <string name="field_copy_action">Copy</string>
@@ -679,6 +687,7 @@
     <string name="calendars_restore_header">Restore</string>
     <string name="calendars_restore_action">Restore from .ics file</string>
     <string name="calendars_restore_hint">Import events from a backup or another calendar app.</string>
+    <string name="calendars_restore_unavailable">No calendar can take the imported events yet.</string>
     <string name="calendars_auto_backup">Automatic backup</string>
     <string name="calendars_auto_backup_hint">Periodically export your local calendars to a folder as an .ics file.</string>
     <string name="calendars_auto_backup_folder">Backup folder</string>

app/src/test/java/de/jeanlucmakiola/calendula/domain/ModelsTest.kt

@@ -36,12 +36,13 @@ class ModelsTest {
     }
 
     @Test
-    fun `FailureReason enum has all six variants`() {
+    fun `FailureReason enum has all seven variants`() {
         assertThat(FailureReason.values().toSet()).isEqualTo(
             setOf(
                 FailureReason.PermissionRevoked,
                 FailureReason.NoCalendarsConfigured,
                 FailureReason.AllCalendarsHidden,
+                FailureReason.NoImportTarget,
                 FailureReason.ProviderUnavailable,
                 FailureReason.EventNotFound,
                 FailureReason.Unknown,

app/src/test/java/de/jeanlucmakiola/calendula/domain/ics/IcsGoogleImportTest.kt

@@ -0,0 +1,116 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.Availability
+import kotlinx.datetime.TimeZone
+import org.junit.jupiter.api.Test
+
+/**
+ * Reading a Google Calendar export (Codeberg #304), whose dialect the parser had
+ * never been held to: `VTIMEZONE` blocks with `X-LIC-LOCATION`, `TZID`-qualified
+ * `DTSTART`/`EXDATE`, folded `DESCRIPTION` and `ATTENDEE` lines, `RECURRENCE-ID`
+ * overrides written as separate `VEVENT`s, and `@google.com` UIDs.
+ *
+ * The fixture is a trimmed copy of what "Settings → Import & export → Export"
+ * produces, CRLF and all. Note that Google hands that export out as a **zip**
+ * containing one `.ics` per calendar — the file here is one member of it.
+ */
+class IcsGoogleImportTest {
+
+    private val parser = IcsParser(TimeZone.of("Europe/Berlin"))
+
+    private val result: IcsParseResult = parser.parse(
+        checkNotNull(
+            javaClass.classLoader?.getResourceAsStream("ics/google-calendar-export.ics"),
+        ).use { it.readBytes().toString(Charsets.UTF_8) },
+    )
+
+    private fun event(summary: String) = result.events.single { it.summary == summary }
+
+    @Test
+    fun `every master event imports and the VTIMEZONE block is not mistaken for one`() {
+        assertThat(result.events.map { it.summary })
+            .containsExactly("Team standup", "Day off", "Christmas break")
+    }
+
+    @Test
+    fun `X-WR-CALNAME names the calendar for all of them`() {
+        assertThat(result.events.map { it.calendarName }.distinct())
+            .containsExactly("jane@example.com")
+    }
+
+    @Test
+    fun `a TZID-qualified start resolves against the device tz database`() {
+        val standup = event("Team standup")
+        assertThat(standup.isAllDay).isFalse()
+        assertThat(standup.zoneId).isEqualTo("Europe/Berlin")
+        // 10:00 CEST is 08:00 UTC.
+        assertThat(standup.start.toString()).isEqualTo("2026-09-15T08:00:00Z")
+        assertThat((standup.end - standup.start).inWholeMinutes).isEqualTo(90)
+    }
+
+    @Test
+    fun `the recurrence rule and its TZID-qualified EXDATE survive`() {
+        val standup = event("Team standup")
+        assertThat(standup.recurrenceRule).isEqualTo("FREQ=WEEKLY;BYDAY=TU")
+        assertThat(standup.exDates).containsExactly("20260929T080000Z")
+    }
+
+    @Test
+    fun `the moved occurrence is skipped rather than imported as a duplicate`() {
+        // Google writes a RECURRENCE-ID override as its own VEVENT carrying the
+        // master's UID. Importing it would put a second "standup" in the
+        // calendar; Calendula models no overrides, so it is reported instead.
+        assertThat(result.events.map { it.summary }).doesNotContain("Team standup (moved)")
+        assertThat(result.warnings).contains(IcsParseWarning.ModifiedOccurrenceSkipped)
+    }
+
+    @Test
+    fun `a folded DESCRIPTION is unfolded and unescaped`() {
+        assertThat(event("Team standup").description).isEqualTo(
+            "Weekly sync with the team.\nAgenda lives in the shared doc, see the link below.",
+        )
+    }
+
+    @Test
+    fun `an escaped comma in LOCATION comes back as a comma`() {
+        assertThat(event("Team standup").location).isEqualTo("Meeting room 2, 3rd floor")
+    }
+
+    @Test
+    fun `attendees are reported rather than silently dropped`() {
+        assertThat(result.warnings).contains(IcsParseWarning.AttendeesIgnored)
+    }
+
+    @Test
+    fun `a timed VALARM becomes its lead time in minutes`() {
+        assertThat(event("Team standup").semanticReminderMinutes()).containsExactly(30)
+    }
+
+    @Test
+    fun `an all-day event keeps the single day the file gives it`() {
+        val dayOff = event("Day off")
+        assertThat(dayOff.isAllDay).isTrue()
+        assertThat((dayOff.end - dayOff.start).inWholeDays).isEqualTo(1)
+        assertThat(dayOff.availability).isEqualTo(Availability.Free)
+    }
+
+    @Test
+    fun `an all-day alarm comes back as whole days before`() {
+        // Google writes an all-day reminder as a whole-day offset from the
+        // event's UTC midnight; a day has to survive as a day.
+        assertThat(event("Day off").semanticReminderMinutes()).containsExactly(1440)
+    }
+
+    @Test
+    fun `a multi-day all-day event keeps its exclusive DTEND span`() {
+        val christmas = event("Christmas break")
+        assertThat(christmas.isAllDay).isTrue()
+        assertThat((christmas.end - christmas.start).inWholeDays).isEqualTo(3)
+    }
+
+    @Test
+    fun `no recurrence rule is repaired - Google writes them well-formed`() {
+        assertThat(result.warnings).doesNotContain(IcsParseWarning.RecurrenceRuleRepaired)
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/domain/ics/IcsUnterminatedComponentTest.kt

@@ -0,0 +1,66 @@
+package de.jeanlucmakiola.calendula.domain.ics
+
+import kotlinx.datetime.TimeZone
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Test
+
+/**
+ * A component whose `END:` line never arrives (a download cut short, a producer
+ * that dropped a line). `indexOfEnd` falls back to the end of the file, so the
+ * block is read as if it had been closed.
+ */
+class IcsUnterminatedComponentTest {
+
+    private val parser = IcsParser(TimeZone.of("Europe/Berlin"))
+
+    @Test
+    fun `file truncated mid-property keeps the event it had started`() {
+        val result = parser.parse(
+            """
+            BEGIN:VCALENDAR
+            VERSION:2.0
+            BEGIN:VEVENT
+            UID:truncated-1@fixture
+            SUMMARY:Cut off mid-file
+            DTSTART:20260924T100000Z
+            DTEND:20260924T1
+            """.trimIndent(),
+        )
+        assertEquals(1, result.events.size)
+        val event = result.events.single()
+        assertEquals("Cut off mid-file", event.summary)
+        // The truncated DTEND does not parse, so the event is zero length.
+        assertEquals(event.start, event.end)
+        assertEquals(emptySet<IcsParseWarning>(), result.warnings)
+    }
+
+    @Test
+    fun `a missing END between two events does not merge them`() {
+        val result = parser.parse(
+            """
+            BEGIN:VCALENDAR
+            VERSION:2.0
+            BEGIN:VEVENT
+            UID:first@fixture
+            SUMMARY:First event
+            DTSTART:20260924T100000Z
+            DTEND:20260924T110000Z
+            BEGIN:VEVENT
+            UID:second@fixture
+            SUMMARY:Second event
+            DTSTART:20260925T100000Z
+            DTEND:20260925T110000Z
+            END:VEVENT
+            END:VCALENDAR
+            """.trimIndent(),
+        )
+        assertEquals(
+            listOf("First event", "Second event"),
+            result.events.map { it.summary },
+        )
+        assertEquals(
+            listOf("first@fixture", "second@fixture"),
+            result.events.map { it.uid },
+        )
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/ui/calendars/BackupUiStateTest.kt

@@ -0,0 +1,90 @@
+package de.jeanlucmakiola.calendula.ui.calendars
+
+import com.google.common.truth.Truth.assertThat
+import de.jeanlucmakiola.calendula.domain.CalendarSource
+import de.jeanlucmakiola.calendula.domain.FailureReason
+import org.junit.jupiter.api.Test
+
+/** What the Backup & restore screen offers for a given calendar list (#304). */
+class BackupUiStateTest {
+
+    private fun cal(
+        id: Long,
+        local: Boolean = false,
+        writable: Boolean = true,
+        visible: Boolean = true,
+        managed: Boolean = false,
+        syncs: Boolean = true,
+    ) = CalendarSource(
+        id = id,
+        displayName = "Calendar $id",
+        accountName = "acc@example.com",
+        accountType = if (local) "LOCAL" else "com.google",
+        color = 0,
+        isVisibleInSystem = visible,
+        canModifyContents = writable,
+        isLocal = local,
+        isManaged = managed,
+        syncsEvents = syncs,
+    )
+
+    private fun failure(state: BackupUiState) = (state as BackupUiState.Failure).reason
+
+    private fun ready(state: BackupUiState) = state as BackupUiState.Ready
+
+    @Test
+    fun `no calendars at all reports the empty device`() {
+        assertThat(failure(backupUiState(emptyList())))
+            .isEqualTo(FailureReason.NoCalendarsConfigured)
+    }
+
+    @Test
+    fun `a synced writable calendar can receive a restore`() {
+        val state = ready(backupUiState(listOf(cal(1L))))
+        assertThat(state.canImport).isTrue()
+        assertThat(state.exportable).isEmpty()
+    }
+
+    @Test
+    fun `the reported case - only a calendar that cannot take events`() {
+        // #304: a Google account with calendar sync switched off leaves nothing
+        // exportable and nothing importable, which used to render a blank screen.
+        assertThat(failure(backupUiState(listOf(cal(1L, syncs = false)))))
+            .isEqualTo(FailureReason.NoImportTarget)
+    }
+
+    @Test
+    fun `a read-only subscription is no import target either`() {
+        assertThat(failure(backupUiState(listOf(cal(1L, writable = false)))))
+            .isEqualTo(FailureReason.NoImportTarget)
+    }
+
+    @Test
+    fun `everything switched off is reported as hidden, not as a missing target`() {
+        // The remedy differs: a visibility switch fixes this one.
+        assertThat(failure(backupUiState(listOf(cal(1L, visible = false)))))
+            .isEqualTo(FailureReason.AllCalendarsHidden)
+    }
+
+    @Test
+    fun `a hidden local calendar still exports`() {
+        // Export reads the provider directly, so system visibility is irrelevant
+        // to it — calling this a failure would hide a working action.
+        val state = ready(backupUiState(listOf(cal(1L, local = true, visible = false))))
+        assertThat(state.exportable).hasSize(1)
+        assertThat(state.canImport).isFalse()
+    }
+
+    @Test
+    fun `a managed special-dates mirror is neither exportable nor a target`() {
+        assertThat(failure(backupUiState(listOf(cal(1L, local = true, managed = true)))))
+            .isEqualTo(FailureReason.NoImportTarget)
+    }
+
+    @Test
+    fun `a local calendar alongside a synced one offers both halves`() {
+        val state = ready(backupUiState(listOf(cal(1L, local = true), cal(2L))))
+        assertThat(state.exportable.map { it.id }).containsExactly(1L)
+        assertThat(state.canImport).isTrue()
+    }
+}

app/src/test/java/de/jeanlucmakiola/calendula/ui/common/TimelineZoomTest.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.ui.common
 
+import androidx.compose.ui.unit.Density
 import androidx.compose.ui.unit.dp
 import com.google.common.truth.Truth.assertThat
 import org.junit.jupiter.api.Test
@@ -75,17 +76,16 @@ class TimelineZoomTest {
     }
 
     @Test
-    fun `a pinch held against a fractional bound stays put`() {
-        // A bound that is not a whole pixel is a height the pinch can be pushed
-        // against but never land on, so every frame of a held gesture would look
-        // like a scale change and hand the focal anchor a scroll correction.
+    fun `a pinch held against either bound stays put`() {
         val fillPx = 62.083f
         val maxPx = 616.5f
 
         val floor = pinchedHourHeightPx(target = 1f, fillPx, maxPx)
         val ceiling = pinchedHourHeightPx(target = 9_000f, fillPx, maxPx)
 
-        assertThat(floor).isEqualTo(63f)
+        // The ceiling is pulled onto the pixel grid so it stays landable; the
+        // fill floor is landable as it is, being the clamp result itself.
+        assertThat(floor).isEqualTo(fillPx)
         assertThat(ceiling).isEqualTo(616f)
         // Landing there and being pushed further must not move them again.
         assertThat(pinchedHourHeightPx(floor * 0.9f, fillPx, maxPx)).isEqualTo(floor)
@@ -100,6 +100,35 @@ class TimelineZoomTest {
         assertThat(floor * 24).isAtLeast(viewport)
     }
 
+    @Test
+    fun `pinching all the way out leaves nothing to scroll`() {
+        // #290: rounding the fill floor up to a whole pixel made the day one
+        // pixel per hour taller than the viewport it was supposed to fill, so a
+        // fully zoomed-out timeline still scrolled a hair and bounced off
+        // Android's overscroll stretch -- while FitDay, at the same zoom, sat
+        // still. 1490 is deliberately not divisible by 24.
+        val viewport = 1490f
+        val floor = pinchedHourHeightPx(target = 1f, fillPx = viewport / 24f, maxPx = 616f)
+        assertThat(floor * 24).isWithin(0.01f).of(viewport)
+    }
+
+    @Test
+    fun `the pinch floor is the height FitDay resolves to`() {
+        // The inconsistency the issue is about: the two ways to reach "the whole
+        // day on one screen" have to arrive at the same height.
+        val density = Density(2.5f)
+        val viewport = 596.dp
+        with(density) {
+            val fitDay = TimelineScale.FitDay.hourHeight(viewport).toPx()
+            val pinched = pinchedHourHeightPx(
+                target = 1f,
+                fillPx = fillHourHeight(viewport).toPx(),
+                maxPx = MAX_PINCH_HOUR_HEIGHT.toPx(),
+            )
+            assertThat(pinched).isWithin(0.01f).of(fitDay)
+        }
+    }
+
     @Test
     fun `a settled pinch is what gets persisted`() {
         var persisted: TimelineScale? = null

app/src/test/resources/ics/google-calendar-export.ics

@@ -0,0 +1,91 @@
+BEGIN:VCALENDAR
+PRODID:-//Google Inc//Google Calendar 70.9054//EN
+VERSION:2.0
+CALSCALE:GREGORIAN
+METHOD:PUBLISH
+X-WR-CALNAME:jane@example.com
+X-WR-TIMEZONE:Europe/Berlin
+BEGIN:VTIMEZONE
+TZID:Europe/Berlin
+X-LIC-LOCATION:Europe/Berlin
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19700329T020000
+RRULE:FREQ=YEARLY;BYMONTH=3;BYDAY=-1SU
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19701025T030000
+RRULE:FREQ=YEARLY;BYMONTH=10;BYDAY=-1SU
+END:STANDARD
+END:VTIMEZONE
+BEGIN:VEVENT
+DTSTART;TZID=Europe/Berlin:20260915T100000
+DTEND;TZID=Europe/Berlin:20260915T113000
+RRULE:FREQ=WEEKLY;BYDAY=TU
+EXDATE;TZID=Europe/Berlin:20260929T100000
+DTSTAMP:20260912T183000Z
+UID:0abcdef1234567890abcdef12345@google.com
+CREATED:20260901T120000Z
+DESCRIPTION:Weekly sync with the team.\nAgenda lives in the shared doc\, see
+  the link below.
+LAST-MODIFIED:20260902T081500Z
+LOCATION:Meeting room 2\, 3rd floor
+SEQUENCE:0
+STATUS:CONFIRMED
+SUMMARY:Team standup
+TRANSP:OPAQUE
+ORGANIZER;CN=Jane Doe:mailto:jane@example.com
+ATTENDEE;CUTYPE=INDIVIDUAL;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;CN=John:m
+ ailto:john@example.com
+BEGIN:VALARM
+ACTION:DISPLAY
+DESCRIPTION:This is an event reminder
+TRIGGER:-PT30M
+END:VALARM
+END:VEVENT
+BEGIN:VEVENT
+DTSTART;TZID=Europe/Berlin:20260929T140000
+DTEND;TZID=Europe/Berlin:20260929T153000
+DTSTAMP:20260912T183000Z
+UID:0abcdef1234567890abcdef12345@google.com
+RECURRENCE-ID;TZID=Europe/Berlin:20260929T100000
+CREATED:20260901T120000Z
+LAST-MODIFIED:20260910T091500Z
+SEQUENCE:1
+STATUS:CONFIRMED
+SUMMARY:Team standup (moved)
+TRANSP:OPAQUE
+END:VEVENT
+BEGIN:VEVENT
+DTSTART;VALUE=DATE:20261024
+DTEND;VALUE=DATE:20261025
+DTSTAMP:20260912T183000Z
+UID:1bcdef01234567890abcdef23456@google.com
+CREATED:20260820T101500Z
+LAST-MODIFIED:20260820T101500Z
+SEQUENCE:0
+STATUS:CONFIRMED
+SUMMARY:Day off
+TRANSP:TRANSPARENT
+BEGIN:VALARM
+ACTION:DISPLAY
+DESCRIPTION:This is an event reminder
+TRIGGER:-P1D
+END:VALARM
+END:VEVENT
+BEGIN:VEVENT
+DTSTART;VALUE=DATE:20261224
+DTEND;VALUE=DATE:20261227
+DTSTAMP:20260912T183000Z
+UID:2cdef012345678901abcdef34567@google.com
+SEQUENCE:0
+STATUS:CONFIRMED
+SUMMARY:Christmas break
+TRANSP:TRANSPARENT
+END:VEVENT
+END:VCALENDAR