From 2b2a31ecda1b2f56b25a01c7dbd409069c6178ea Mon Sep 17 00:00:00 2001
From: Jean-Luc Makiola <jlmakiola@noreply.codeberg.org>
Date: Wed, 14 Oct 2026 15:57:32 +0200
Subject: [PATCH] Create an event from shared or selected text (#306) (#396)

Shared text, or text picked with the new "Create event" entry in the selection menu, opens the new-event form prefilled. The share's subject becomes the title, or the first line if there is no subject, and the rest of the text goes into the description. Start and length use the usual defaults (next full hour, default duration). Calendula doesn't try to read a date out of the text.

Differences from the plan in the issue comment:
- The line used as the title is left out of the description, so it doesn't show up twice.
- Titles are capped at 255 characters. If a title gets cut, the full text stays in the description.
- Sharing a plain-text file no longer sends it to the .ics importer.
- A saved or dismissed prefilled form no longer reopens after rotating the phone. This also fixes it for "add to calendar" requests from other apps.
- If a second request comes in while a prefilled form is open, it replaces the form when nothing was changed. Otherwise the save / discard / keep editing prompt comes first.
- If Calendula was started just for the request, closing or saving the form takes you back to the app you came from.

Closes #306

Co-authored-by: Jean-Luc Makiola <business@jeanlucmakiola.de>
Reviewed-on: https://codeberg.org/jlmakiola/calendula/pulls/396
---
 app/src/main/AndroidManifest.xml              | 13 ++++
 .../jeanlucmakiola/calendula/MainActivity.kt  | 72 ++++++++++++++++--
 .../calendula/domain/InsertEventForm.kt       | 36 +++++++--
 .../calendula/ui/CalendarHost.kt              | 75 ++++++++++++++-----
 .../jeanlucmakiola/calendula/ui/RootScreen.kt |  2 +
 .../calendula/ui/edit/EventEditScreen.kt      | 11 ++-
 app/src/main/res/values/strings.xml           |  3 +
 .../calendula/domain/SharedTextTest.kt        | 57 ++++++++++++++
 8 files changed, 239 insertions(+), 30 deletions(-)
 create mode 100644 app/src/test/java/de/jeanlucmakiola/calendula/domain/SharedTextTest.kt

diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index a7e97b68..e1f6110f 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -151,6 +151,19 @@
                 <data android:mimeType="application/ics" />
             </intent-filter>
 
+            <!-- Text shared or selected in another app opens a prefilled new
+                 event (MainActivity.sharedTextExtrasOrNull, issue #306). -->
+            <intent-filter>
+                <action android:name="android.intent.action.SEND" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/plain" />
+            </intent-filter>
+            <intent-filter android:label="@string/process_text_create_event">
+                <action android:name="android.intent.action.PROCESS_TEXT" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <data android:mimeType="text/plain" />
+            </intent-filter>
+
             <!-- Let another app or widget (e.g. the Todo Agenda widget) launch us
                  to create a new event, the way the AOSP calendar accepts it:
                  ACTION_INSERT on the events *dir* mime type, carrying the new
diff --git a/app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt b/app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt
index 218feb3a..ef240199 100644
--- a/app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt
+++ b/app/src/main/java/de/jeanlucmakiola/calendula/MainActivity.kt
@@ -31,6 +31,7 @@ import de.jeanlucmakiola.calendula.data.prefs.ThemeMode
 import de.jeanlucmakiola.calendula.data.prefs.is24Hour
 import de.jeanlucmakiola.calendula.domain.EventForm
 import de.jeanlucmakiola.calendula.domain.buildInsertEventForm
+import de.jeanlucmakiola.calendula.domain.sharedTextOrNull
 import de.jeanlucmakiola.calendula.ui.RootScreen
 import de.jeanlucmakiola.calendula.ui.common.LocalShowHourGrid
 import de.jeanlucmakiola.calendula.ui.common.LocalMultiDayCount
@@ -86,10 +87,18 @@ class MainActivity : AppCompatActivity() {
     private var requestedImportUri by mutableStateOf<Uri?>(null)
 
     // A prefilled new-event form from an external ACTION_INSERT launch (another
-    // app/widget asking us to create an event, issue #30). Consumed once by
-    // CalendarHost, which opens it in the create form for review.
+    // app/widget asking us to create an event, issue #30) or shared text (#306).
+    // Consumed once by CalendarHost, which opens it in the create form for review.
     private var requestedInsert by mutableStateOf<InsertRequest?>(null)
 
+    // Whether such a form is still open. Only then does a recreation re-read the
+    // intent to bring it back; a saved or dismissed one stays closed.
+    private var insertFormOpen = false
+
+    // Started just for an external create, so closing its form returns to the
+    // app that asked instead of leaving the calendar on top of it.
+    private var launchedForInsert = false
+
     // An external "edit this event" (ACTION_EDIT on content://.../events/<id>):
     // opens the occurrence in the edit form. Same occurrence-key shape as the
     // detail channel; consumed once by CalendarHost.
@@ -128,7 +137,8 @@ class MainActivity : AppCompatActivity() {
         //
         // Only those channels are held back. An .ics import or a prefilled
         // create form keeps no saved state of its own, so re-reading the intent
-        // is what carries one through a recreation.
+        // is what carries one through a recreation — the create form only while
+        // it's still open.
         val replaying = savedInstanceState != null || intent.isRelaunch()
         if (!replaying) {
             requestedDetailKey = intent.detailKeyOrNull() ?: intent.viewEventKeyOrNull()
@@ -137,7 +147,11 @@ class MainActivity : AppCompatActivity() {
         requestedNav = intent.navRequestOrNull()
             ?.takeUnless { replaying && it is WidgetNavRequest.OpenEvent }
         requestedImportUri = intent.importUriOrNull()
-        requestedInsert = intent.insertRequestOrNull()
+        val insertOpenBefore = savedInstanceState?.getBoolean(KEY_INSERT_FORM_OPEN) == true
+        requestedInsert = intent.createRequestOrNull()?.takeIf { !replaying || insertOpenBefore }
+        insertFormOpen = requestedInsert != null
+        launchedForInsert = savedInstanceState?.getBoolean(KEY_LAUNCHED_FOR_INSERT)
+            ?: (requestedInsert != null)
         if (CrashReporter.shouldPrompt(this)) pendingCrashReport = CrashReporter.pendingReport(this)
         setContent {
             // One activity-scoped SettingsViewModel drives both the theme here
@@ -208,6 +222,10 @@ class MainActivity : AppCompatActivity() {
                             requestedInsertForm = requestedInsert?.form,
                             requestedInsertSource = requestedInsert?.source ?: ImportSource.Insert,
                             onInsertConsumed = { requestedInsert = null },
+                            onExternalFormClosed = {
+                                insertFormOpen = false
+                                if (launchedForInsert) finish()
+                            },
                             requestedEditKey = requestedEditKey,
                             onEditKeyConsumed = { requestedEditKey = null },
                         )
@@ -261,12 +279,21 @@ class MainActivity : AppCompatActivity() {
         CrashReporter.markHealthy(this)
     }
 
+    override fun onSaveInstanceState(outState: Bundle) {
+        super.onSaveInstanceState(outState)
+        outState.putBoolean(KEY_INSERT_FORM_OPEN, insertFormOpen)
+        outState.putBoolean(KEY_LAUNCHED_FOR_INSERT, launchedForInsert)
+    }
+
     override fun onNewIntent(intent: Intent) {
         super.onNewIntent(intent)
         (intent.detailKeyOrNull() ?: intent.viewEventKeyOrNull())?.let { requestedDetailKey = it }
         intent.navRequestOrNull()?.let { requestedNav = it }
         intent.importUriOrNull()?.let { requestedImportUri = it }
-        intent.insertRequestOrNull()?.let { requestedInsert = it }
+        intent.createRequestOrNull()?.let {
+            requestedInsert = it
+            insertFormOpen = true
+        }
         intent.editEventKeyOrNull()?.let { requestedEditKey = it }
     }
 
@@ -288,7 +315,9 @@ class MainActivity : AppCompatActivity() {
     private fun Intent.importUriOrNull(): Uri? {
         val uri = when (action) {
             Intent.ACTION_VIEW -> data
+            // Plain text is a create (#306), never a file to import.
             Intent.ACTION_SEND -> IntentCompat.getParcelableExtra(this, Intent.EXTRA_STREAM, Uri::class.java)
+                .takeUnless { type == SHARED_TEXT_TYPE }
             else -> null
         } ?: return null
         // The calendar "view time" Uri (a date tap) is also ACTION_VIEW/content;
@@ -333,6 +362,36 @@ class MainActivity : AppCompatActivity() {
         return InsertRequest(form, if (namesEnd) ImportSource.Insert else ImportSource.InsertOpenEnded)
     }
 
+    /** Any external request to create an event: shared text or an insert intent. */
+    private fun Intent.createRequestOrNull(): InsertRequest? = sharedTextRequestOrNull() ?: insertRequestOrNull()
+
+    /**
+     * Plain text shared into us (`ACTION_SEND`) or picked from a text-selection
+     * menu (`ACTION_PROCESS_TEXT`), as a new event at the default time (#306).
+     */
+    private fun Intent.sharedTextRequestOrNull(): InsertRequest? {
+        val shared = when (action) {
+            Intent.ACTION_SEND -> if (type == SHARED_TEXT_TYPE) {
+                sharedTextOrNull(
+                    subject = getCharSequenceExtra(Intent.EXTRA_SUBJECT)?.toString(),
+                    text = getCharSequenceExtra(Intent.EXTRA_TEXT)?.toString(),
+                )
+            } else {
+                null
+            }
+            Intent.ACTION_PROCESS_TEXT ->
+                sharedTextOrNull(subject = null, text = getCharSequenceExtra(Intent.EXTRA_PROCESS_TEXT)?.toString())
+            else -> null
+        } ?: return null
+        val form = buildInsertEventForm(
+            title = shared.title,
+            description = shared.description,
+            zone = TimeZone.currentSystemDefault(),
+            now = Clock.System.now(),
+        )
+        return InsertRequest(form, ImportSource.InsertOpenEnded)
+    }
+
     /** A Long extra's value, or null when the extra is absent. */
     private fun Intent.longExtraOrNull(key: String): Long? =
         if (hasExtra(key)) getLongExtra(key, 0L) else null
@@ -458,6 +517,9 @@ class MainActivity : AppCompatActivity() {
         // The calendar provider's authority/host. A date tap arrives as
         // ACTION_VIEW on content://com.android.calendar/time/<epochMillis>.
         private const val CALENDAR_PROVIDER_HOST = "com.android.calendar"
+        private const val SHARED_TEXT_TYPE = "text/plain"
+        private const val KEY_INSERT_FORM_OPEN = "insert_form_open"
+        private const val KEY_LAUNCHED_FOR_INSERT = "launched_for_insert"
 
         private const val EXTRA_EVENT_ID = "de.jeanlucmakiola.calendula.extra.EVENT_ID"
         private const val EXTRA_BEGIN_MILLIS = "de.jeanlucmakiola.calendula.extra.BEGIN"
diff --git a/app/src/main/java/de/jeanlucmakiola/calendula/domain/InsertEventForm.kt b/app/src/main/java/de/jeanlucmakiola/calendula/domain/InsertEventForm.kt
index 2bf1c249..a537275d 100644
--- a/app/src/main/java/de/jeanlucmakiola/calendula/domain/InsertEventForm.kt
+++ b/app/src/main/java/de/jeanlucmakiola/calendula/domain/InsertEventForm.kt
@@ -24,13 +24,13 @@ import kotlin.time.Instant
  * the extras lives in `MainActivity.insertFormOrNull`.
  */
 fun buildInsertEventForm(
-    beginMillis: Long?,
-    endMillis: Long?,
-    isAllDay: Boolean,
+    beginMillis: Long? = null,
+    endMillis: Long? = null,
+    isAllDay: Boolean = false,
     title: String?,
     description: String?,
-    location: String?,
-    rrule: String?,
+    location: String? = null,
+    rrule: String? = null,
     zone: TimeZone,
     now: Instant,
 ): EventForm {
@@ -71,3 +71,29 @@ internal fun nextFullHour(now: Instant): Instant {
     val hourMillis = 3_600_000L
     return Instant.fromEpochMilliseconds((now.toEpochMilliseconds() / hourMillis + 1) * hourMillis)
 }
+
+/** Title and description for text shared or selected into the app (#306). */
+data class SharedText(val title: String, val description: String)
+
+/**
+ * Split shared text into an event title and description: the share's subject
+ * becomes the title and the text the description. Without a subject the text's
+ * first non-blank line is the title and the rest the description. A title longer
+ * than [maxTitle] is cut, and the full text then stays in the description.
+ * Null when there is nothing to use.
+ */
+fun sharedTextOrNull(subject: String?, text: String?, maxTitle: Int = 255): SharedText? {
+    val body = text?.trim().orEmpty()
+    val given = subject?.trim()?.takeIf { it.isNotEmpty() }
+    val (title, rest) = if (given != null) {
+        given to body
+    } else {
+        val lines = body.lines()
+        val first = lines.firstOrNull()?.trim()?.takeIf { it.isNotEmpty() } ?: return null
+        first to lines.drop(1).joinToString("\n").trim()
+    }
+    if (title.length <= maxTitle) return SharedText(title, rest)
+    val cut = title.take(maxTitle).let { if (it.last().isHighSurrogate()) it.dropLast(1) else it }
+    val full = if (given != null) listOf(given, body).filter { it.isNotEmpty() }.joinToString("\n\n") else body
+    return SharedText(cut.trimEnd(), full)
+}
diff --git a/app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHost.kt b/app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHost.kt
index 565bf08c..cf06ac17 100644
--- a/app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHost.kt
+++ b/app/src/main/java/de/jeanlucmakiola/calendula/ui/CalendarHost.kt
@@ -19,6 +19,7 @@ import androidx.compose.material3.Scaffold
 import androidx.compose.material3.TopAppBarDefaults
 import androidx.compose.material3.rememberDrawerState
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.key
 import androidx.compose.runtime.setValue
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
@@ -81,6 +82,7 @@ import de.jeanlucmakiola.calendula.ui.common.rememberCalendarSlideSpec
 import de.jeanlucmakiola.calendula.ui.common.selectView
 import de.jeanlucmakiola.calendula.ui.common.viewBaseStack
 import de.jeanlucmakiola.calendula.ui.detail.EventDetailScreen
+import de.jeanlucmakiola.calendula.ui.edit.EventEditViewModel
 import de.jeanlucmakiola.calendula.ui.edit.EventEditScreen
 import de.jeanlucmakiola.calendula.ui.edit.ImportSource
 import de.jeanlucmakiola.calendula.ui.imports.ImportScreen
@@ -132,6 +134,7 @@ fun CalendarHost(
     requestedInsertForm: EventForm? = null,
     requestedInsertSource: ImportSource = ImportSource.Insert,
     onInsertConsumed: () -> Unit = {},
+    onExternalFormClosed: () -> Unit = {},
     requestedEditKey: LongArray? = null,
     onEditKeyConsumed: () -> Unit = {},
     viewModel: CalendarHostViewModel = hiltViewModel(),
@@ -277,6 +280,34 @@ fun CalendarHost(
     // Which channel filled [importForm]: an .ics file (prompt to apply the default
     // reminder) or an ACTION_INSERT intent (apply it automatically) — #49.
     var importFormSource by remember { mutableStateOf(ImportSource.File) }
+    // Bumped per open, so even an equal prefill starts a fresh form.
+    var importFormId by remember { mutableIntStateOf(0) }
+    // Whether [importForm] came from an external create request (#30, #306);
+    // closing it then hands control back to whoever asked.
+    var importFromRequest by rememberSaveable { mutableStateOf(false) }
+    // A second external request that arrived while a prefilled form was open:
+    // it waits behind that form's unsaved-changes prompt, then opens.
+    var pendingInsert by remember { mutableStateOf<Pair<EventForm, ImportSource>?>(null) }
+    val importViewModel: EventEditViewModel = hiltViewModel(key = "import")
+    fun openImportForm(form: EventForm, source: ImportSource, fromRequest: Boolean = false) {
+        importFormSource = source
+        importForm = form
+        importFormId++
+        importFromRequest = fromRequest
+    }
+    fun closeImportForm() {
+        val next = pendingInsert
+        pendingInsert = null
+        if (next != null) {
+            openImportForm(next.first, next.second, fromRequest = true)
+        } else {
+            importForm = null
+            if (importFromRequest) {
+                importFromRequest = false
+                onExternalFormClosed()
+            }
+        }
+    }
     // A restore (in-app "Restore from .ics" button) always runs the full import
     // flow — picker + summary — even for a single-event file, because the intent
     // is "restore a backup", not "add this one event". An externally opened .ics
@@ -306,8 +337,11 @@ fun CalendarHost(
     // reveals on top of whatever was open without extra dismissal.
     LaunchedEffect(requestedInsertForm) {
         if (requestedInsertForm != null) {
-            importFormSource = requestedInsertSource
-            importForm = requestedInsertForm
+            if (importForm == null) {
+                openImportForm(requestedInsertForm, requestedInsertSource, fromRequest = true)
+            } else {
+                pendingInsert = requestedInsertForm to requestedInsertSource
+            }
             onInsertConsumed()
         }
     }
@@ -323,6 +357,9 @@ fun CalendarHost(
         editKey = null
         importUri = null
         importForm = null
+        importFromRequest = false
+        pendingInsert = null
+        importViewModel.reset()
     }
 
     // An external "edit this event" (ACTION_EDIT, e.g. an assistant/task app or
@@ -570,8 +607,7 @@ fun CalendarHost(
                     onEdit = onEditEvent,
                     onDuplicate = { form ->
                         // A fresh event, like a duplicate from the detail screen (#52).
-                        importFormSource = ImportSource.Insert
-                        importForm = form
+                        openImportForm(form, ImportSource.Insert)
                     },
                     chipShown = moveOutcome != null || selectionFailure != null,
                     onDismissChip = {
@@ -681,8 +717,7 @@ fun CalendarHost(
                         // Reuse the prefilled-create overlay: a duplicate is a
                         // fresh event, so it applies the default reminder like an
                         // in-app new event (#52).
-                        importFormSource = ImportSource.Insert
-                        importForm = form
+                        openImportForm(form, ImportSource.Insert)
                         detailKey = null
                     },
                     visible = detailKey != null,
@@ -727,8 +762,7 @@ fun CalendarHost(
                     },
                     onManageCalendars = { showCalendars = true },
                     onDuplicate = { form ->
-                        importFormSource = ImportSource.Insert
-                        importForm = form
+                        openImportForm(form, ImportSource.Insert)
                     },
                     // Opened straight from a tap (#178) there's no detail screen
                     // below to show why, so open it.
@@ -786,21 +820,24 @@ fun CalendarHost(
                     importUri = null
                     calendarsAfterImport = false
                     backupAfterImport = false
-                    importFormSource = ImportSource.File
-                    importForm = form
+                    openImportForm(form, ImportSource.File)
                 },
             )
         }
         importForm?.let { form ->
-            EventEditScreen(
-                initialDateIso = null,
-                initialForm = form,
-                initialFormSource = importFormSource,
-                onClose = { importForm = null },
-                onSaved = { importForm = null },
-                onManageCalendars = { showCalendars = true },
-                viewModel = hiltViewModel(key = "import"),
-            )
+            key(importFormId) {
+                EventEditScreen(
+                    initialDateIso = null,
+                    initialForm = form,
+                    initialFormSource = importFormSource,
+                    onClose = ::closeImportForm,
+                    onSaved = ::closeImportForm,
+                    onManageCalendars = { showCalendars = true },
+                    leaveRequested = pendingInsert != null,
+                    onLeaveDeclined = { pendingInsert = null },
+                    viewModel = importViewModel,
+                )
+            }
         }
 
         // Declared last so it covers every overlay that can open it: Settings,
diff --git a/app/src/main/java/de/jeanlucmakiola/calendula/ui/RootScreen.kt b/app/src/main/java/de/jeanlucmakiola/calendula/ui/RootScreen.kt
index 9b24e6ba..62f034fb 100644
--- a/app/src/main/java/de/jeanlucmakiola/calendula/ui/RootScreen.kt
+++ b/app/src/main/java/de/jeanlucmakiola/calendula/ui/RootScreen.kt
@@ -54,6 +54,7 @@ fun RootScreen(
     requestedInsertSource: de.jeanlucmakiola.calendula.ui.edit.ImportSource =
         de.jeanlucmakiola.calendula.ui.edit.ImportSource.Insert,
     onInsertConsumed: () -> Unit = {},
+    onExternalFormClosed: () -> Unit = {},
     requestedEditKey: LongArray? = null,
     onEditKeyConsumed: () -> Unit = {},
 ) {
@@ -155,6 +156,7 @@ fun RootScreen(
                 requestedInsertForm = requestedInsertForm,
                 requestedInsertSource = requestedInsertSource,
                 onInsertConsumed = onInsertConsumed,
+                onExternalFormClosed = onExternalFormClosed,
                 requestedEditKey = requestedEditKey,
                 onEditKeyConsumed = onEditKeyConsumed,
             )
diff --git a/app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditScreen.kt b/app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditScreen.kt
index a16ac12b..3e170fd2 100644
--- a/app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditScreen.kt
+++ b/app/src/main/java/de/jeanlucmakiola/calendula/ui/edit/EventEditScreen.kt
@@ -225,6 +225,8 @@ fun EventEditScreen(
     onDuplicate: ((EventForm) -> Unit)? = null,
     onDeleted: () -> Unit = onSaved,
     onLoadFailed: () -> Unit = onClose,
+    leaveRequested: Boolean = false,
+    onLeaveDeclined: () -> Unit = {},
     visible: Boolean = true,
     viewModel: EventEditViewModel = hiltViewModel(),
 ) {
@@ -269,6 +271,10 @@ fun EventEditScreen(
     val requestClose = {
         if (hasUnsavedChanges) showLeavePrompt = true else close()
     }
+    // Something else wants this form's place, e.g. a second share (#306).
+    LaunchedEffect(leaveRequested) {
+        if (leaveRequested) requestClose()
+    }
     // The event vanished before the form could load it — fall back to the
     // detail screen, which shows its own failure state.
     LaunchedEffect(loadFailed) {
@@ -420,7 +426,10 @@ fun EventEditScreen(
                 showLeavePrompt = false
                 close()
             },
-            onDismiss = { showLeavePrompt = false },
+            onDismiss = {
+                showLeavePrompt = false
+                if (leaveRequested) onLeaveDeclined()
+            },
         )
     }
 
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index dd8bbd59..8a49eb1a 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -844,6 +844,9 @@
     <string name="shortcut_new_event_short">New event</string>
     <string name="shortcut_new_event_long">Create a new event</string>
 
+    <!-- Text-selection menu entry -->
+    <string name="process_text_create_event">Create event</string>
+
     <!-- Quick Settings tile -->
     <string name="qs_tile_new_event_label">New event</string>
     <string name="settings_qs_tile">Add Quick Settings tile</string>
diff --git a/app/src/test/java/de/jeanlucmakiola/calendula/domain/SharedTextTest.kt b/app/src/test/java/de/jeanlucmakiola/calendula/domain/SharedTextTest.kt
new file mode 100644
index 00000000..e4d12a83
--- /dev/null
+++ b/app/src/test/java/de/jeanlucmakiola/calendula/domain/SharedTextTest.kt
@@ -0,0 +1,57 @@
+package de.jeanlucmakiola.calendula.domain
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class SharedTextTest {
+
+    @Test
+    fun `subject becomes the title and the text the description`() {
+        assertThat(sharedTextOrNull("Dinner", "Friday at Luigi's\nBring wine"))
+            .isEqualTo(SharedText("Dinner", "Friday at Luigi's\nBring wine"))
+    }
+
+    @Test
+    fun `without a subject the first line is the title and the rest the description`() {
+        assertThat(sharedTextOrNull(null, "\n  Dentist  \n\nCheck-up, room 4\n"))
+            .isEqualTo(SharedText("Dentist", "Check-up, room 4"))
+    }
+
+    @Test
+    fun `a single line is the title only`() {
+        assertThat(sharedTextOrNull("  ", " Call mum ")).isEqualTo(SharedText("Call mum", ""))
+    }
+
+    @Test
+    fun `subject without text leaves the description empty`() {
+        assertThat(sharedTextOrNull("Meeting", null)).isEqualTo(SharedText("Meeting", ""))
+    }
+
+    @Test
+    fun `a long first line is cut and the full text kept as the description`() {
+        val line = "a".repeat(300)
+        val shared = sharedTextOrNull(null, "$line\nmore")!!
+        assertThat(shared.title).isEqualTo("a".repeat(255))
+        assertThat(shared.description).isEqualTo("$line\nmore")
+    }
+
+    @Test
+    fun `a long subject is cut and kept in full above the text`() {
+        val subject = "s".repeat(300)
+        val shared = sharedTextOrNull(subject, "body")!!
+        assertThat(shared.title).hasLength(255)
+        assertThat(shared.description).isEqualTo("$subject\n\nbody")
+    }
+
+    @Test
+    fun `the cut never splits a surrogate pair`() {
+        val shared = sharedTextOrNull(null, "a".repeat(254) + "😀" + "b")!!
+        assertThat(shared.title).isEqualTo("a".repeat(254))
+    }
+
+    @Test
+    fun `nothing usable is null`() {
+        assertThat(sharedTextOrNull(null, null)).isNull()
+        assertThat(sharedTextOrNull(" ", "\n \n")).isNull()
+    }
+}