Tapping an event can open the edit form (#178) (#394)

New setting under Settings → Views → Events: "Tapping an event opens" Details (default) or Edit form. The long-press toggle moves into the same group.

- Taps in the views and in search open the editor directly for events in writable calendars. Read-only events, reminder notifications and widgets always open the details.
- Installs without write access are asked for it on the tap; refusing opens the details instead.
- The editor gets a back guard: with unsaved changes it asks to save, discard or keep editing; otherwise it closes silently.
- The editor gets Duplicate, Share and Delete in an overflow menu, so skipping the details doesn't lose them.
- If the event can't be loaded, the details screen opens and shows why.
- Each editor overlay (create, edit, duplicate/import) now has its own ViewModel. Duplicating from an edited form previously reused the edit form's state.
- Deletes from the details screen, the editor and the selection bar share one error mapping. Deleting an event that's already gone counts as deleted in the details screen and the editor.

Deviation from the issue: it asked for back to save automatically. Following the discussion in the comments, auto-save isn't in this PR. Back asks only when something actually changed, and Details stays the default.

Closes #178

Co-authored-by: Jean-Luc Makiola <business@jeanlucmakiola.de>
Reviewed-on: https://codeberg.org/jlmakiola/calendula/pulls/394

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

@@ -346,6 +346,19 @@ class SettingsPrefs @Inject constructor(
         store.edit { it[DRAG_TO_RESCHEDULE_KEY] = enabled }
     }
 
+    /**
+     * Whether tapping an event in the calendar views opens the edit form instead
+     * of the detail screen (#178). Defaults to OFF; read-only events and
+     * reminder notifications always open the detail screen.
+     */
+    val tapOpensEditor: Flow<Boolean> = store.data.map { prefs ->
+        prefs[TAP_OPENS_EDITOR_KEY] ?: false
+    }
+
+    suspend fun setTapOpensEditor(enabled: Boolean) {
+        store.edit { it[TAP_OPENS_EDITOR_KEY] = enabled }
+    }
+
     /**
      * How far ahead the in-app Agenda screen shows events (v2.11). Defaults to
      * [AgendaRange.Month] — a month of upcoming events. Independent of the
@@ -1019,6 +1032,7 @@ class SettingsPrefs @Inject constructor(
         internal val TIMELINE_SCALE_KEY = stringPreferencesKey("timeline_scale")
         internal val TODAY_BUTTON_IN_TOOLBAR_KEY = booleanPreferencesKey("today_button_in_toolbar")
         internal val DRAG_TO_RESCHEDULE_KEY = booleanPreferencesKey("drag_to_reschedule")
+        internal val TAP_OPENS_EDITOR_KEY = booleanPreferencesKey("tap_opens_editor")
         internal val DEFAULT_VIEW_KEY = stringPreferencesKey("default_view")
         internal val QUICK_SWITCH_VIEWS_KEY = stringPreferencesKey("quick_switch_views")
         internal val DRAWER_VIEW_ORDER_KEY = stringPreferencesKey("drawer_view_order")

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

@@ -60,6 +60,7 @@ import de.jeanlucmakiola.calendula.ui.common.EventMoveHost
 import de.jeanlucmakiola.calendula.ui.common.EventSelectionHost
 import de.jeanlucmakiola.calendula.ui.common.eventActionFailureMessage
 import de.jeanlucmakiola.calendula.ui.common.rememberFabSelection
+import de.jeanlucmakiola.calendula.ui.common.rememberWriteGateOr
 import de.jeanlucmakiola.calendula.ui.common.EventMoveScope
 import de.jeanlucmakiola.calendula.ui.common.LocalEventMove
 import de.jeanlucmakiola.calendula.ui.common.LocalManageCalendars
@@ -192,7 +193,7 @@ fun CalendarHost(
     // placeholder — so the destination never loads a bogus id=0 on first frame.
     var detailKey by rememberSaveable { mutableStateOf<LongArray?>(null) }
     var heldKey by remember { mutableStateOf<LongArray?>(null) }
-    val onEventClick: (EventInstance) -> Unit = { event ->
+    val onOpenDetail: (EventInstance) -> Unit = { event ->
         val key = longArrayOf(
             event.eventId,
             event.start.toEpochMilliseconds(),
@@ -410,6 +411,18 @@ fun CalendarHost(
         heldEditKey = key
         editKey = key
     }
+    // A tap opens the edit form instead of the detail screen when the user chose
+    // so (#178) — only for events whose calendar takes writes.
+    val tapOpensEditor = viewModel.tapOpensEditor.collectAsStateWithLifecycle().value
+    val actionCalendars by eventActions.calendars.collectAsStateWithLifecycle()
+    val requireWriteOr = rememberWriteGateOr()
+    val onEventClick: (EventInstance) -> Unit = { event ->
+        if (tapOpensEditor && actionCalendars[event.calendarId]?.canModifyContents == true) {
+            requireWriteOr({ onEditEvent(event) }, { onOpenDetail(event) })
+        } else {
+            onOpenDetail(event)
+        }
+    }
     // Off by preference (#173) switches off the gesture, not the scope: blocks
     // register no drag, while the edit form and its TalkBack action stay put.
     val dragToReschedule = viewModel.dragToReschedule.collectAsStateWithLifecycle().value
@@ -685,6 +698,7 @@ fun CalendarHost(
                     onSaved = { createDateIso = null },
                     onManageCalendars = { showCalendars = true },
                     visible = createDateIso != null,
+                    viewModel = hiltViewModel(key = "create"),
                 )
             }
         }
@@ -705,7 +719,21 @@ fun CalendarHost(
                         detailKey = null
                     },
                     onManageCalendars = { showCalendars = true },
+                    onDuplicate = { form ->
+                        importFormSource = ImportSource.Insert
+                        importForm = form
+                    },
+                    // Opened straight from a tap (#178) there's no detail screen
+                    // below to show why, so open it.
+                    onLoadFailed = {
+                        editKey = null
+                        if (detailKey == null) {
+                            heldKey = key
+                            detailKey = key
+                        }
+                    },
                     visible = editKey != null,
+                    viewModel = hiltViewModel(key = "edit"),
                 )
             }
         }
@@ -764,6 +792,7 @@ fun CalendarHost(
                 onClose = { importForm = null },
                 onSaved = { importForm = null },
                 onManageCalendars = { showCalendars = true },
+                viewModel = hiltViewModel(key = "import"),
             )
         }
 

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

@@ -78,4 +78,12 @@ class CalendarHostViewModel @Inject constructor(
             started = SharingStarted.WhileSubscribed(5_000L),
             initialValue = false,
         )
+
+    /** Whether tapping an event opens the edit form rather than the detail screen (#178). */
+    val tapOpensEditor: StateFlow<Boolean> = prefs.tapOpensEditor
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5_000L),
+            initialValue = false,
+        )
 }

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

@@ -5,6 +5,7 @@ import android.content.Context
 import android.content.Intent
 import android.content.pm.PackageManager
 import android.net.Uri
+import android.util.Log
 import androidx.activity.compose.rememberLauncherForActivityResult
 import androidx.activity.result.contract.ActivityResultContracts
 import androidx.compose.foundation.layout.Arrangement
@@ -25,12 +26,14 @@ import androidx.compose.ui.unit.dp
 import androidx.core.content.ContextCompat
 import de.jeanlucmakiola.calendula.R
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
+import de.jeanlucmakiola.calendula.data.calendar.NoSuchEventException
 import de.jeanlucmakiola.calendula.data.ics.IcsExporter
 import de.jeanlucmakiola.calendula.domain.EventDetail
 import de.jeanlucmakiola.calendula.domain.RecurringWriteScope
 import de.jeanlucmakiola.calendula.domain.ics.IcsWriter
 import de.jeanlucmakiola.calendula.domain.ics.toShareIcsEvent
 import de.jeanlucmakiola.floret.components.OptionCard
+import kotlin.coroutines.cancellation.CancellationException
 import kotlin.time.Clock
 
 /**
@@ -67,6 +70,28 @@ suspend fun CalendarRepository.deleteEvent(
     RecurringWriteScope.ThisAndFollowing -> deleteEventFromOccurrence(eventId, beginMillis)
 }
 
+/** How a [tryDeleteEvent] ended. */
+enum class DeleteOutcome { Deleted, Gone, NeedsPermission, Failed }
+
+/** [deleteEvent], with the provider's failures mapped to a [DeleteOutcome]. */
+suspend fun CalendarRepository.tryDeleteEvent(
+    eventId: Long,
+    beginMillis: Long,
+    scope: RecurringWriteScope,
+): DeleteOutcome = try {
+    deleteEvent(eventId, beginMillis, scope)
+    DeleteOutcome.Deleted
+} catch (e: CancellationException) {
+    throw e
+} catch (e: SecurityException) {
+    DeleteOutcome.NeedsPermission
+} catch (e: NoSuchEventException) {
+    DeleteOutcome.Gone
+} catch (e: Exception) {
+    Log.w("EventActions", "Delete failed (scope=$scope, eventId=$eventId)", e)
+    DeleteOutcome.Failed
+}
+
 /**
  * Runs an action that writes to the calendar, asking for `WRITE_CALENDAR` first
  * where the install only holds read access (v1.0 installs). A grant continues
@@ -74,15 +99,22 @@ suspend fun CalendarRepository.deleteEvent(
  */
 @Composable
 fun rememberWriteGate(): (() -> Unit) -> Unit {
+    val gate = rememberWriteGateOr()
+    return { action -> gate(action) {} }
+}
+
+/** [rememberWriteGate], running the fallback instead when the user refuses. */
+@Composable
+fun rememberWriteGateOr(): (action: () -> Unit, fallback: () -> Unit) -> Unit {
     val context = LocalContext.current
-    var pending by remember { mutableStateOf<(() -> Unit)?>(null) }
+    var pending by remember { mutableStateOf<Pair<() -> Unit, () -> Unit>?>(null) }
     val launcher = rememberLauncherForActivityResult(
         contract = ActivityResultContracts.RequestPermission(),
     ) { granted ->
-        if (granted) pending?.invoke()
+        pending?.let { (action, fallback) -> if (granted) action() else fallback() }
         pending = null
     }
-    return { action ->
+    return { action, fallback ->
         val granted = ContextCompat.checkSelfPermission(
             context,
             Manifest.permission.WRITE_CALENDAR,
@@ -90,7 +122,7 @@ fun rememberWriteGate(): (() -> Unit) -> Unit {
         if (granted) {
             action()
         } else {
-            pending = action
+            pending = action to fallback
             launcher.launch(Manifest.permission.WRITE_CALENDAR)
         }
     }

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

@@ -87,17 +87,11 @@ class EventActionsViewModel @Inject constructor(
         _deletePrompt.value = null
         viewModelScope.launch {
             val event = prompt.event
-            _failure.value = try {
-                repository.deleteEvent(event.eventId, event.start.toEpochMilliseconds(), scope)
-                null
-            } catch (e: CancellationException) {
-                throw e
-            } catch (e: SecurityException) {
-                EventActionFailure.WriteDenied
-            } catch (e: NoSuchEventException) {
-                EventActionFailure.Gone
-            } catch (e: Exception) {
-                EventActionFailure.DeleteFailed
+            _failure.value = when (repository.tryDeleteEvent(event.eventId, event.start.toEpochMilliseconds(), scope)) {
+                DeleteOutcome.Deleted -> null
+                DeleteOutcome.Gone -> EventActionFailure.Gone
+                DeleteOutcome.NeedsPermission -> EventActionFailure.WriteDenied
+                DeleteOutcome.Failed -> EventActionFailure.DeleteFailed
             }
         }
     }

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

@@ -12,7 +12,8 @@ import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.FailureReason
 import de.jeanlucmakiola.calendula.domain.RecurringWriteScope
 import de.jeanlucmakiola.calendula.domain.toDuplicateForm
-import de.jeanlucmakiola.calendula.ui.common.deleteEvent
+import de.jeanlucmakiola.calendula.ui.common.DeleteOutcome
+import de.jeanlucmakiola.calendula.ui.common.tryDeleteEvent
 import de.jeanlucmakiola.calendula.ui.common.stageEventShare
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.withContext
@@ -111,15 +112,11 @@ class EventDetailViewModel @Inject constructor(
         if (_deleteState.value == DeleteUiState.Deleting) return
         viewModelScope.launch {
             _deleteState.value = DeleteUiState.Deleting
-            _deleteState.value = try {
-                repository.deleteEvent(target.eventId, target.beginMillis, scope)
-                DeleteUiState.Deleted
-            } catch (e: CancellationException) {
-                throw e
-            } catch (e: SecurityException) {
-                DeleteUiState.NeedsPermission
-            } catch (e: Exception) {
-                DeleteUiState.Failed
+            // Already gone is what a delete wants anyway.
+            _deleteState.value = when (repository.tryDeleteEvent(target.eventId, target.beginMillis, scope)) {
+                DeleteOutcome.Deleted, DeleteOutcome.Gone -> DeleteUiState.Deleted
+                DeleteOutcome.NeedsPermission -> DeleteUiState.NeedsPermission
+                DeleteOutcome.Failed -> DeleteUiState.Failed
             }
         }
     }

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

@@ -36,6 +36,15 @@ import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.Notes
 import androidx.compose.material.icons.filled.Add
+import kotlinx.coroutines.launch
+import de.jeanlucmakiola.calendula.ui.common.sendEventShare
+import de.jeanlucmakiola.calendula.ui.common.rememberWriteGate
+import de.jeanlucmakiola.calendula.ui.common.DeleteEventDialog
+import androidx.compose.runtime.rememberCoroutineScope
+import androidx.compose.material.icons.filled.Share
+import androidx.compose.material.icons.filled.MoreVert
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.ContentCopy
 import androidx.compose.material.icons.filled.ArrowDropDown
 import androidx.compose.material.icons.filled.CalendarMonth
 import androidx.compose.material.icons.filled.Close
@@ -192,6 +201,10 @@ import kotlin.time.Clock
  * first asks how far the change reaches (this occurrence / this and
  * following / whole series) — then closes. The calendar picker offers only
  * writable calendars; when editing, the calendar is fixed.
+ *
+ * Leaving with unsaved changes asks to save, discard or keep editing (#178).
+ * While editing, the overflow menu offers Duplicate (the form as it stands,
+ * handed to [onDuplicate] as a new event), Share and Delete.
  */
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -205,6 +218,9 @@ fun EventEditScreen(
     initialForm: EventForm? = null,
     initialFormSource: ImportSource = ImportSource.File,
     onManageCalendars: (() -> Unit)? = null,
+    onDuplicate: ((EventForm) -> Unit)? = null,
+    onDeleted: () -> Unit = onSaved,
+    onLoadFailed: () -> Unit = onClose,
     visible: Boolean = true,
     viewModel: EventEditViewModel = hiltViewModel(),
 ) {
@@ -236,10 +252,19 @@ fun EventEditScreen(
         viewModel.reset()
         onClose()
     }
-    // The event vanished between the detail screen and the edit tap — fall
-    // back to the detail screen, which shows its own failure state.
+    val hasUnsavedChanges by viewModel.hasUnsavedChanges.collectAsStateWithLifecycle()
+    var showLeavePrompt by rememberSaveable { mutableStateOf(false) }
+    var showDeleteDialog by rememberSaveable { mutableStateOf(false) }
+    val requestClose = {
+        if (hasUnsavedChanges) showLeavePrompt = true else close()
+    }
+    // The event vanished before the form could load it — fall back to the
+    // detail screen, which shows its own failure state.
     LaunchedEffect(loadFailed) {
-        if (loadFailed) close()
+        if (loadFailed) {
+            viewModel.reset()
+            onLoadFailed()
+        }
     }
 
     val context = LocalContext.current
@@ -263,14 +288,49 @@ fun EventEditScreen(
         }
     }
 
+    val scope = rememberCoroutineScope()
+    val requireWrite = rememberWriteGate()
+    val shareFailedMessage = stringResource(R.string.event_share_failed)
+    val shareChooserTitle = stringResource(R.string.event_share_chooser_title)
+    val onShareClick: () -> Unit = {
+        scope.launch {
+            val uri = viewModel.shareUri()
+            val sent = uri != null && context.sendEventShare(uri, shareChooserTitle)
+            if (!sent) snackbarHostState.showSnackbar(shareFailedMessage)
+        }
+    }
+    // The copy opens over this form; a form with nothing to lose steps aside.
+    val onDuplicateClick: () -> Unit = {
+        requireWrite {
+            viewModel.duplicateForm()?.let { form ->
+                onDuplicate?.invoke(form)
+                if (!hasUnsavedChanges) close()
+            }
+        }
+    }
+
     val saveFailedMessage = stringResource(R.string.event_edit_save_failed)
     val writeDeniedMessage = stringResource(R.string.event_edit_write_denied)
+    val deleteFailedMessage = stringResource(R.string.event_delete_failed)
+    val deleteDeniedMessage = stringResource(R.string.event_delete_write_denied)
     LaunchedEffect(state?.saveState) {
         when (state?.saveState) {
             SaveUiState.Saved -> {
                 viewModel.reset()
                 onSaved()
             }
+            SaveUiState.Deleted -> {
+                viewModel.reset()
+                onDeleted()
+            }
+            SaveUiState.DeleteFailed -> {
+                viewModel.consumeSaveResult()
+                snackbarHostState.showSnackbar(deleteFailedMessage, duration = SnackbarDuration.Long)
+            }
+            SaveUiState.DeleteDenied -> {
+                viewModel.consumeSaveResult()
+                snackbarHostState.showSnackbar(deleteDeniedMessage, duration = SnackbarDuration.Long)
+            }
             // A failed save leaves the form looking unchanged, so the snackbar is
             // the only sign anything happened — long rather than the default
             // flash (Codeberg #234: it read as "nothing happens at all").
@@ -288,7 +348,7 @@ fun EventEditScreen(
     }
 
     Scaffold(
-        modifier = Modifier.predictiveBack(onBack = close, visible = visible),
+        modifier = Modifier.predictiveBack(onBack = requestClose, visible = visible),
         snackbarHost = { SnackbarHost(snackbarHostState) },
         topBar = {
             TopAppBar(
@@ -296,7 +356,7 @@ fun EventEditScreen(
                 // matching the detail screen's bare top bar.
                 title = {},
                 navigationIcon = {
-                    IconButton(onClick = close) {
+                    IconButton(onClick = requestClose) {
                         Icon(
                             imageVector = Icons.Default.Close,
                             contentDescription = stringResource(R.string.event_edit_close),
@@ -304,6 +364,15 @@ fun EventEditScreen(
                     }
                 },
                 actions = {
+                    if (state?.isEditing == true) {
+                        EditActionsMenu(
+                            canDelete = state?.isManaged == false,
+                            canDuplicate = onDuplicate != null,
+                            onDuplicate = onDuplicateClick,
+                            onShare = onShareClick,
+                            onDelete = { requireWrite { showDeleteDialog = true } },
+                        )
+                    }
                     Button(
                         onClick = onSaveClick,
                         enabled = state != null && state?.saveState != SaveUiState.Saving,
@@ -330,6 +399,32 @@ fun EventEditScreen(
         }
     }
 
+    if (showLeavePrompt) {
+        UnsavedChangesDialog(
+            onSave = {
+                showLeavePrompt = false
+                onSaveClick()
+            },
+            onDiscard = {
+                showLeavePrompt = false
+                close()
+            },
+            onDismiss = { showLeavePrompt = false },
+        )
+    }
+
+    val recurs = viewModel.editedEventRecurs()
+    if (showDeleteDialog && recurs != null) {
+        DeleteEventDialog(
+            isRecurring = recurs,
+            onConfirm = { deleteScope ->
+                showDeleteDialog = false
+                viewModel.delete(deleteScope)
+            },
+            onDismiss = { showDeleteDialog = false },
+        )
+    }
+
     if (state?.saveState == SaveUiState.AwaitingScope) {
         SaveScopeDialog(
             recurrenceChanged = state?.recurrenceChanged == true,
@@ -374,6 +469,90 @@ fun EventEditScreen(
     }
 }
 
+/** Duplicate, Share and Delete for the event being edited, behind an overflow button. */
+@Composable
+private fun EditActionsMenu(
+    canDelete: Boolean,
+    canDuplicate: Boolean,
+    onDuplicate: () -> Unit,
+    onShare: () -> Unit,
+    onDelete: () -> Unit,
+) {
+    var open by remember { mutableStateOf(false) }
+    Box {
+        IconButton(onClick = { open = true }) {
+            Icon(
+                imageVector = Icons.Default.MoreVert,
+                contentDescription = stringResource(R.string.event_edit_more_actions),
+            )
+        }
+        DropdownMenu(expanded = open, onDismissRequest = { open = false }) {
+            if (canDuplicate) {
+                DropdownMenuItem(
+                    text = { Text(stringResource(R.string.event_detail_duplicate)) },
+                    leadingIcon = { Icon(Icons.Default.ContentCopy, contentDescription = null) },
+                    onClick = {
+                        open = false
+                        onDuplicate()
+                    },
+                )
+            }
+            DropdownMenuItem(
+                text = { Text(stringResource(R.string.event_detail_share)) },
+                leadingIcon = { Icon(Icons.Default.Share, contentDescription = null) },
+                onClick = {
+                    open = false
+                    onShare()
+                },
+            )
+            // Managed special-dates events have no delete, as on the detail screen.
+            if (canDelete) {
+                DropdownMenuItem(
+                    text = { Text(stringResource(R.string.event_detail_delete)) },
+                    leadingIcon = { Icon(Icons.Default.Delete, contentDescription = null) },
+                    onClick = {
+                        open = false
+                        onDelete()
+                    },
+                )
+            }
+        }
+    }
+}
+
+/**
+ * Asked when leaving the form with unsaved changes (#178). Dismissing keeps
+ * editing; a form with nothing changed closes without asking.
+ */
+@Composable
+private fun UnsavedChangesDialog(
+    onSave: () -> Unit,
+    onDiscard: () -> Unit,
+    onDismiss: () -> Unit,
+) {
+    AlertDialog(
+        onDismissRequest = onDismiss,
+        title = { Text(stringResource(R.string.event_edit_unsaved_title)) },
+        text = {
+            Column(verticalArrangement = Arrangement.spacedBy(8.dp)) {
+                OptionCard(
+                    label = stringResource(R.string.event_edit_unsaved_save),
+                    onClick = onSave,
+                )
+                OptionCard(
+                    label = stringResource(R.string.event_edit_unsaved_discard),
+                    onClick = onDiscard,
+                )
+            }
+        },
+        confirmButton = {
+            TextButton(onClick = onDismiss) {
+                Text(stringResource(R.string.event_edit_unsaved_keep))
+            }
+        },
+    )
+}
+
 /**
  * Offer to apply the settings default reminder to an event opened from a `.ics`
  * file. The file's own reminders are kept unless the user accepts. A plain

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

@@ -77,6 +77,11 @@ sealed interface SaveUiState {
     data object Gone : SaveUiState
     data object Saving : SaveUiState
     data object Saved : SaveUiState
+    /** The event was deleted from the form (#178). */
+    data object Deleted : SaveUiState
+    data object DeleteFailed : SaveUiState
+    /** WRITE_CALENDAR was revoked before a delete from the form. */
+    data object DeleteDenied : SaveUiState
     /** WRITE_CALENDAR was revoked between the tap and the provider call. */
     data object NeedsPermission : SaveUiState
     data object Failed : SaveUiState

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

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.ui.edit
 
+import android.net.Uri
 import android.util.Log
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
@@ -7,6 +8,7 @@ import dagger.hilt.android.lifecycle.HiltViewModel
 import de.jeanlucmakiola.calendula.data.calendar.CalendarRepository
 import de.jeanlucmakiola.calendula.data.calendar.NoSuchEventException
 import de.jeanlucmakiola.calendula.data.di.IoDispatcher
+import de.jeanlucmakiola.calendula.data.ics.IcsExporter
 import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
 import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs
 import de.jeanlucmakiola.calendula.data.prefs.firstDayOfWeek
@@ -18,6 +20,7 @@ import de.jeanlucmakiola.calendula.domain.CalendarSource
 import de.jeanlucmakiola.calendula.domain.EditSnapshot
 import de.jeanlucmakiola.calendula.domain.EventAttendee
 import de.jeanlucmakiola.calendula.domain.EventColorOption
+import de.jeanlucmakiola.calendula.domain.EventDetail
 import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.EventFormField
 import de.jeanlucmakiola.calendula.domain.RecurringWriteScope
@@ -26,6 +29,9 @@ import de.jeanlucmakiola.calendula.domain.populatedFields
 import de.jeanlucmakiola.calendula.domain.problems
 import de.jeanlucmakiola.calendula.domain.toEditSnapshot
 import de.jeanlucmakiola.calendula.ui.detail.EventDetailViewModel.Companion.NO_OCCURRENCE_TIME
+import de.jeanlucmakiola.calendula.ui.common.DeleteOutcome
+import de.jeanlucmakiola.calendula.ui.common.tryDeleteEvent
+import de.jeanlucmakiola.calendula.ui.common.stageEventShare
 import de.jeanlucmakiola.calendula.ui.common.wallClockTime
 import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.ExperimentalCoroutinesApi
@@ -133,6 +139,7 @@ class EventEditViewModel @Inject constructor(
     private val repository: CalendarRepository,
     private val prefs: CalendarPrefs,
     private val settingsPrefs: SettingsPrefs,
+    private val icsExporter: IcsExporter,
     @IoDispatcher private val io: CoroutineDispatcher,
 ) : ViewModel() {
 
@@ -157,6 +164,9 @@ class EventEditViewModel @Inject constructor(
     // 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)
+    // Set by the first change the user makes, so a form only holding its own
+    // defaults or an import's prefill can be left without asking.
+    private val _edited = MutableStateFlow(false)
 
     /** True when the event to edit couldn't be loaded; the screen closes itself. */
     val loadFailed: StateFlow<Boolean> = _loadFailed.asStateFlow()
@@ -177,6 +187,8 @@ class EventEditViewModel @Inject constructor(
         val beginMillis: Long,
         val endMillis: Long,
         val zone: TimeZone,
+        /** The event as loaded, on the tapped occurrence's times — what Share exports. */
+        val detail: EventDetail,
     ) {
         val original: EventForm get() = snapshot.form
     }
@@ -312,6 +324,18 @@ class EventEditViewModel @Inject constructor(
             initialValue = null,
         )
 
+    /**
+     * Whether leaving now would lose something the user did (#178): an edit that
+     * differs from the loaded event, or any change to a new or imported form.
+     */
+    val hasUnsavedChanges: StateFlow<Boolean> = combine(_form, _editTarget, _edited) { form, target, edited ->
+        when {
+            form == null -> false
+            target != null -> form != target.original
+            else -> edited
+        }
+    }.stateIn(viewModelScope, SharingStarted.Eagerly, false)
+
     /**
      * First day of the week for ordering the recurrence weekday toggles — the
      * app's "week starts on" preference, matching the calendar views (Auto
@@ -496,7 +520,7 @@ class EventEditViewModel @Inject constructor(
         val prompt = _importReminderPrompt.value ?: return
         _importReminderPrompt.value = null
         // Already frozen as touched by openImported; this just swaps the values.
-        update { it.copy(reminders = prompt.defaultReminders) }
+        edit { it.copy(reminders = prompt.defaultReminders) }
         _revealed.value = _revealed.value + EventFormField.Reminders
     }
 
@@ -531,7 +555,13 @@ class EventEditViewModel @Inject constructor(
             val end = endMillis.takeUnless { it == NO_OCCURRENCE_TIME }
                 ?: detail.instance.end.toEpochMilliseconds()
             val snapshot = detail.toEditSnapshot(begin, end, zone)
-            _editTarget.value = EditTarget(eventId, snapshot, begin, end, zone)
+            val occurrence = detail.copy(
+                instance = detail.instance.copy(
+                    start = Instant.fromEpochMilliseconds(begin),
+                    end = Instant.fromEpochMilliseconds(end),
+                ),
+            )
+            _editTarget.value = EditTarget(eventId, snapshot, begin, end, zone, occurrence)
             // Sections holding data must show even when not in the defaults.
             _revealed.value = snapshot.form.populatedFields()
             _form.value = snapshot.form
@@ -549,6 +579,7 @@ class EventEditViewModel @Inject constructor(
         _remindersTouched.value = false
         _durationTouched.value = false
         _importReminderPrompt.value = null
+        _edited.value = false
     }
 
     /** Unfold one optional field, picked in the "more fields" dialog. */
@@ -559,24 +590,24 @@ class EventEditViewModel @Inject constructor(
     // The title field wraps (multi-line) so long titles stay visible (#33), but
     // a title is one logical line: drop any newline the IME's Enter key or a
     // paste would introduce, so it never reaches the provider's TITLE column.
-    fun setTitle(value: String) = update {
+    fun setTitle(value: String) = edit {
         val cleaned = value.replace("\n", "").replace("\r", "")
         it.copy(title = capLength(cleaned, it.title))
     }
     // The location wraps too (#273) but is likewise one logical line. A pasted
     // multi-line address joins the way the contact picker's does (#146), so it
     // never runs together into "12 Main St10115 Berlin".
-    fun setLocation(value: String) = update {
+    fun setLocation(value: String) = edit {
         val cleaned = value.replace(LINE_BREAK, ", ")
         it.copy(location = capLength(cleaned, it.location))
     }
-    fun setDescription(value: String) = update { it.copy(description = value) }
+    fun setDescription(value: String) = edit { it.copy(description = value) }
     fun setAllDay(value: Boolean) {
         // Going all-day drops any pinned zone: the times become bare dates that
         // the provider stores UTC-anchored, so a zone could only misrepresent
         // them. Coming back out of all-day leaves the event on the device zone,
         // which is the same thing a fresh event gets.
-        update { it.copy(isAllDay = value, timezone = if (value) null else it.timezone) }
+        edit { it.copy(isAllDay = value, timezone = if (value) null else it.timezone) }
         // The default reminder differs for all-day vs timed; re-apply the
         // type-appropriate default unless the user has hand-edited it (guarded).
         applyDefaultReminder()
@@ -591,7 +622,7 @@ class EventEditViewModel @Inject constructor(
      * time — only real picks are remembered, not the device fallback.
      */
     fun setTimezone(zoneId: String?) {
-        update { it.copy(timezone = zoneId) }
+        edit { it.copy(timezone = zoneId) }
         if (zoneId != null) {
             viewModelScope.launch { withContext(io) { settingsPrefs.addRecentTimeZone(zoneId) } }
         }
@@ -603,35 +634,35 @@ class EventEditViewModel @Inject constructor(
      * The event falls back to the new calendar's colour until re-picked.
      */
     fun setCalendar(id: Long) {
-        update { it.copy(calendarId = id, colorKey = null, color = null) }
+        edit { it.copy(calendarId = id, colorKey = null, color = null) }
         // A fresh event re-inherits the new calendar's default reminder and
         // 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) }
+    fun setAvailability(value: Availability) = edit { it.copy(availability = value) }
+    fun setAccessLevel(value: AccessLevel) = edit { it.copy(accessLevel = value) }
 
     /** Pick a palette colour (round-trips via its key); [argb] is its swatch. */
-    fun setColorKey(key: String, argb: Int) = update { it.copy(colorKey = key, color = argb) }
+    fun setColorKey(key: String, argb: Int) = edit { it.copy(colorKey = key, color = argb) }
 
     /** Pick a raw colour (local / opted-in calendars), clearing any palette key. */
-    fun setColorRaw(argb: Int) = update { it.copy(colorKey = null, color = argb) }
+    fun setColorRaw(argb: Int) = edit { it.copy(colorKey = null, color = argb) }
 
     /** Clear the colour so the event inherits its calendar's. */
-    fun clearColor() = update { it.copy(colorKey = null, color = null) }
+    fun clearColor() = edit { it.copy(colorKey = null, color = null) }
 
     /** Bare RRULE value from the recurrence picker; null = does not repeat. */
-    fun setRecurrence(rrule: String?) = update { it.copy(rrule = rrule) }
+    fun setRecurrence(rrule: String?) = edit { it.copy(rrule = rrule) }
 
     fun addReminder(minutes: Int) {
         _remindersTouched.value = true
-        update { it.copy(reminders = (it.reminders + minutes).distinct().sorted()) }
+        edit { it.copy(reminders = (it.reminders + minutes).distinct().sorted()) }
     }
 
     fun removeReminder(minutes: Int) {
         _remindersTouched.value = true
-        update { it.copy(reminders = it.reminders - minutes) }
+        edit { it.copy(reminders = it.reminders - minutes) }
     }
 
     /**
@@ -642,7 +673,7 @@ class EventEditViewModel @Inject constructor(
     fun addAttendee(email: String, name: String = "", optional: Boolean = false) {
         val trimmed = email.trim()
         if (trimmed.isEmpty()) return
-        update { form ->
+        edit { form ->
             val attendee = EventAttendee(email = trimmed, name = name.trim(), optional = optional)
             val rest = form.attendees.filterNot { it.email.equals(trimmed, ignoreCase = true) }
             form.copy(attendees = rest + attendee)
@@ -650,10 +681,10 @@ class EventEditViewModel @Inject constructor(
     }
 
     fun removeAttendee(attendee: EventAttendee) =
-        update { it.copy(attendees = it.attendees.filterNot { a -> a.email.equals(attendee.email, ignoreCase = true) }) }
+        edit { it.copy(attendees = it.attendees.filterNot { a -> a.email.equals(attendee.email, ignoreCase = true) }) }
 
     /** Flip a guest between required and optional (the per-row role toggle). */
-    fun setAttendeeOptional(attendee: EventAttendee, optional: Boolean) = update { form ->
+    fun setAttendeeOptional(attendee: EventAttendee, optional: Boolean) = edit { form ->
         form.copy(
             attendees = form.attendees.map { a ->
                 if (a.email.equals(attendee.email, ignoreCase = true)) a.copy(optional = optional) else a
@@ -669,12 +700,12 @@ class EventEditViewModel @Inject constructor(
     // 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)) }
+        edit { it.copy(end = LocalDateTime(date, it.end.time)) }
     }
 
     fun setEndTime(time: LocalTime) {
         _durationTouched.value = true
-        update { it.copy(end = LocalDateTime(it.end.date, time)) }
+        edit { it.copy(end = LocalDateTime(it.end.date, time)) }
     }
 
     /**
@@ -810,12 +841,39 @@ class EventEditViewModel @Inject constructor(
         }
     }
 
+    /** Whether the event being edited recurs; null while not editing. */
+    fun editedEventRecurs(): Boolean? = _editTarget.value?.let { !it.detail.rrule.isNullOrBlank() }
+
+    /** The form as it stands, as a fresh one-off event — Duplicate in the edit form (#178). */
+    fun duplicateForm(): EventForm? = state.value?.form?.copy(rrule = null)
+
+    /** A staged `.ics` of the event as saved, or null when it can't be built. */
+    suspend fun shareUri(): Uri? {
+        val detail = _editTarget.value?.detail ?: return null
+        return withContext(io) { icsExporter.stageEventShare(detail) }
+    }
+
+    /** Delete the event being edited, as far as [scope] reaches; result lands in [saveState]. */
+    fun delete(scope: RecurringWriteScope) {
+        val target = _editTarget.value ?: return
+        if (_saveState.value == SaveUiState.Saving) return
+        viewModelScope.launch {
+            _saveState.value = SaveUiState.Saving
+            // Already gone is what a delete wants anyway.
+            _saveState.value = when (repository.tryDeleteEvent(target.eventId, target.beginMillis, scope)) {
+                DeleteOutcome.Deleted, DeleteOutcome.Gone -> SaveUiState.Deleted
+                DeleteOutcome.NeedsPermission -> SaveUiState.DeleteDenied
+                DeleteOutcome.Failed -> SaveUiState.DeleteFailed
+            }
+        }
+    }
+
     /** Reset [saveState] after the screen handled a terminal result. */
     fun consumeSaveResult() {
         _saveState.value = SaveUiState.Idle
     }
 
-    private fun moveStart(transform: (LocalDateTime) -> LocalDateTime) = update { form ->
+    private fun moveStart(transform: (LocalDateTime) -> LocalDateTime) = edit { form ->
         val zone = TimeZone.currentSystemDefault()
         val newStart = transform(form.start)
         val duration = form.end.toInstant(zone) - form.start.toInstant(zone)
@@ -826,4 +884,12 @@ class EventEditViewModel @Inject constructor(
     private inline fun update(block: (EventForm) -> EventForm) {
         _form.value = _form.value?.let(block)
     }
+
+    /** A change the user made, as opposed to a default the form applied itself. */
+    private inline fun edit(block: (EventForm) -> EventForm) {
+        val current = _form.value ?: return
+        val next = block(current)
+        if (next != current) _edited.value = true
+        _form.value = next
+    }
 }

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

@@ -47,6 +47,8 @@ data class SettingsUiState(
     val todayButtonInToolbar: Boolean = false,
     /** Whether events can be dragged to another slot to reschedule them (#68, #173). */
     val dragToReschedule: Boolean = true,
+    /** Whether tapping an event opens the edit form instead of the detail screen (#178). */
+    val tapOpensEditor: Boolean = false,
     /** How far ahead the in-app Agenda screen shows events (v2.11). */
     val agendaScreenRange: AgendaRange = AgendaRange.Month,
     /** How far ahead the agenda widget shows events (v2.11). */

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

@@ -148,13 +148,16 @@ class SettingsViewModel @Inject constructor(
                     prefs.softenCalendarColors,
                     combine(
                         prefs.todayButtonInToolbar,
-                        prefs.dragToReschedule,
+                        combine(prefs.dragToReschedule, prefs.tapOpensEditor, ::Pair),
                         prefs.multiDayCount,
                         ::Triple,
                     ),
-                ) { hourLines, weekNumbers, showToday, soften, (todayInToolbar, dragToMove, multiDay) ->
+                ) { hourLines, weekNumbers, showToday, soften, (todayInToolbar, gestures, multiDay) ->
                     DisplayToggles(
-                        hourLines, weekNumbers, showToday, soften, todayInToolbar, dragToMove, multiDay,
+                        hourLines, weekNumbers, showToday, soften, todayInToolbar,
+                        dragToReschedule = gestures.first,
+                        tapOpensEditor = gestures.second,
+                        multiDayCount = multiDay,
                     )
                 },
             ) { view, screenRange, widgetRange, timeFormat, toggles ->
@@ -166,6 +169,7 @@ class SettingsViewModel @Inject constructor(
                     softenColors = toggles.softenColors,
                     todayButtonInToolbar = toggles.todayButtonInToolbar,
                     dragToReschedule = toggles.dragToReschedule,
+                    tapOpensEditor = toggles.tapOpensEditor,
                     multiDayCount = toggles.multiDayCount,
                 )
             },
@@ -202,6 +206,7 @@ class SettingsViewModel @Inject constructor(
                 softenColors = views.softenColors,
                 todayButtonInToolbar = views.todayButtonInToolbar,
                 dragToReschedule = views.dragToReschedule,
+                tapOpensEditor = views.tapOpensEditor,
                 multiDayCount = views.multiDayCount,
                 agendaShowRangeBar = misc.showRangeBar,
                 autofocusEventTitle = misc.autofocusEventTitle,
@@ -305,6 +310,7 @@ class SettingsViewModel @Inject constructor(
         val softenColors: Boolean,
         val todayButtonInToolbar: Boolean,
         val dragToReschedule: Boolean,
+        val tapOpensEditor: Boolean,
         val multiDayCount: Int,
     )
 
@@ -315,6 +321,7 @@ class SettingsViewModel @Inject constructor(
         val softenColors: Boolean,
         val todayButtonInToolbar: Boolean,
         val dragToReschedule: Boolean,
+        val tapOpensEditor: Boolean,
         val multiDayCount: Int,
     )
 
@@ -562,6 +569,10 @@ class SettingsViewModel @Inject constructor(
         viewModelScope.launch { prefs.setDragToReschedule(enabled) }
     }
 
+    fun setTapOpensEditor(enabled: Boolean) {
+        viewModelScope.launch { prefs.setTapOpensEditor(enabled) }
+    }
+
     /**
      * Switch the launcher label (#44). The card highlights at once, then settles
      * on what the component state reports; the writes are binder round-trips and

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

@@ -74,6 +74,7 @@ internal fun ViewsScreen(
     var showDefaultView by remember { mutableStateOf(false) }
     var showWeekStart by remember { mutableStateOf(false) }
     var showTimeFormat by remember { mutableStateOf(false) }
+    var showTapOpens by remember { mutableStateOf(false) }
     var showPastEvents by remember { mutableStateOf(false) }
     var showAgendaScreenRange by remember { mutableStateOf(false) }
     var showTimelineScale by remember { mutableStateOf(false) }
@@ -125,7 +126,7 @@ internal fun ViewsScreen(
         GroupedRow(
             title = stringResource(R.string.settings_dim_completed),
             summary = stringResource(R.string.settings_dim_completed_summary),
-            position = Position.Middle,
+            position = Position.Bottom,
             trailing = {
                 Switch(
                     checked = state.dimCompletedEvents,
@@ -134,6 +135,17 @@ internal fun ViewsScreen(
             },
             onClick = { viewModel.setDimCompletedEvents(!state.dimCompletedEvents) },
         )
+
+        Spacer(Modifier.height(8.dp))
+
+        // How events respond to a tap and a long press (#178, #141).
+        SectionHeader(stringResource(R.string.settings_events_header))
+        GroupedRow(
+            title = stringResource(R.string.settings_tap_opens),
+            summary = tapOpensLabel(state.tapOpensEditor),
+            position = Position.Top,
+            onClick = { showTapOpens = true },
+        )
         GroupedRow(
             title = stringResource(R.string.settings_drag_to_reschedule),
             summary = stringResource(R.string.settings_drag_to_reschedule_summary),
@@ -387,6 +399,18 @@ internal fun ViewsScreen(
             onDismiss = { showTimeFormat = false },
         )
     }
+    if (showTapOpens) {
+        OptionPicker(
+            title = stringResource(R.string.settings_tap_opens),
+            header = { PickerDescription(stringResource(R.string.settings_tap_opens_hint)) },
+            predictiveBack = true,
+            options = listOf(false, true),
+            selected = state.tapOpensEditor,
+            label = { tapOpensLabel(it) },
+            onSelect = viewModel::setTapOpensEditor,
+            onDismiss = { showTapOpens = false },
+        )
+    }
     if (showPastEvents) {
         PastEventsPicker(
             selected = state.pastEventDisplay,
@@ -522,6 +546,11 @@ internal fun weekStartLabel(pref: WeekStartPref): String = when (pref) {
         .getDisplayName(JavaTextStyle.FULL, currentLocale())
 }
 
+@Composable
+private fun tapOpensLabel(editor: Boolean): String = stringResource(
+    if (editor) R.string.settings_tap_opens_editor else R.string.settings_tap_opens_details,
+)
+
 @Composable
 private fun timeFormatLabel(pref: TimeFormatPref): String = stringResource(
     when (pref) {