fix(shareable): headline the group's name, not the invitation

EXTRA_TITLE carried the invitation sentence, so the Sharesheet drew it as
the headline directly above the same sentence as the first line of the
body — and truncated it there, the headline being a single line. The
group's name is what that slot is for.

EXTRA_SUBJECT keeps the sentence. It is an email's subject line rather
than a headline sitting above a body, so there is nothing to repeat.

Author: bmc08gt

apps/flipcash/shared/shareable/src/main/kotlin/com/flipcash/app/shareable/ShareSheetController.kt

@@ -54,7 +54,8 @@ sealed interface Shareable {
      */
     data class GroupInvite(
         val url: String,
-        // The group's name, which the invitation sentence names. Null or blank shares the bare link.
+        // The group's name: the Sharesheet's headline, and what the invitation sentence names.
+        // Null or blank shares the bare link, with no headline.
         val title: String? = null,
         /**
          * The group's picture, as a download URL, for the Sharesheet's preview thumbnail. Null for

apps/flipcash/shared/shareable/src/main/kotlin/com/flipcash/app/shareable/internal/InternalShareSheetController.kt

@@ -303,9 +303,8 @@ internal class InternalShareSheetController(
         // link rather than an invitation with a hole in it. Blank counts as no name: an untitled
         // group reaches this as "" via ChatSubject.Group.title. Same wording as iOS'
         // GroupInviteShareItem, which trims and checks the same way.
-        val invitation = shareable.title
-            ?.takeIf { it.isNotBlank() }
-            ?.let { resources.getString(R.string.message_groupInvite, it.trim()) }
+        val name = shareable.title?.takeIf { it.isNotBlank() }?.trim()
+        val invitation = name?.let { resources.getString(R.string.message_groupInvite, it) }
 
         // The group's own picture as the Sharesheet's thumbnail, so the invite is recognisable
         // before it is sent. Best-effort: no picture, a slow fetch or an expired URL all share
@@ -316,10 +315,14 @@ internal class InternalShareSheetController(
 
         val intent = Intent().apply {
             action = Intent.ACTION_SEND
-            invitation?.let {
-                putExtra(Intent.EXTRA_TITLE, it)
-                putExtra(Intent.EXTRA_SUBJECT, it)
-            }
+            // The headline above the Sharesheet's preview. The group's name, not the invitation:
+            // the sentence is already the first line of the body directly beneath it, and the
+            // headline is one truncated line, so putting it in both says the name twice and cuts
+            // it off once.
+            name?.let { putExtra(Intent.EXTRA_TITLE, it) }
+            // EXTRA_SUBJECT is an email's subject line rather than a preview headline, so the
+            // invitation belongs here — it reads as the message it is, with no body beside it.
+            invitation?.let { putExtra(Intent.EXTRA_SUBJECT, it) }
             putExtra(
                 Intent.EXTRA_TEXT,
                 if (invitation != null) "$invitation\n\n${shareable.url}" else shareable.url

apps/flipcash/shared/shareable/src/test/kotlin/com/flipcash/app/shareable/internal/ShareGroupInviteTest.kt

@@ -45,10 +45,9 @@ class ShareGroupInviteTest {
             "Join Book Club on Flipcash and let's chat\n\nhttps://app.flipcash.com/chat/abc",
             sent.getStringExtra(Intent.EXTRA_TEXT)
         )
-        assertEquals(
-            "Join Book Club on Flipcash and let's chat",
-            sent.getStringExtra(Intent.EXTRA_TITLE)
-        )
+        // The headline names the group; repeating the sentence there would show it twice, once
+        // truncated. The subject is an email's, where the sentence is the message.
+        assertEquals("Book Club", sent.getStringExtra(Intent.EXTRA_TITLE))
         assertEquals(
             "Join Book Club on Flipcash and let's chat",
             sent.getStringExtra(Intent.EXTRA_SUBJECT)