fix(scanner): open group chat invites scanned from a QR code (#1535)

Scanning an app.flipcash.com/chat/{uuid} QR code did nothing from the
camera and showed "no code found" from the gallery. The router already
classifies the link as a GroupChatInvite, but isScannable refused it and
Scanner had no destination for it, so it fell through to an empty route
list.

GroupChatInvite is now scannable and opens the same destination as a
tapped invite link: Sheets.Tips, then Messaging.Chat by chat id, which is
the gated preview for someone who is not yet a member. Login and
EmailVerification stay refused, since they carry secrets.

Author: bmc08gt

apps/flipcash/core/src/main/kotlin/com/flipcash/app/core/navigation/DeeplinkType.kt

@@ -60,9 +60,6 @@ sealed interface DeeplinkType: Parcelable {
      * send as a photo. A new route type is refused until someone adds it here, which is the
      * property an `else -> false` would not have.
      *
-     * [GroupChatInvite] is false because no scan path opens one -- `Scanner`'s `Navigatable`
-     * branch has no case for it. It is a gap named rather than a risk.
-     *
      * iOS's equivalent is `ScanViewModel.canScanQR`.
      */
     val isScannable: Boolean
@@ -72,11 +69,11 @@ sealed interface DeeplinkType: Parcelable {
             is TipChat,
             is Tipcard,
             is TipcardByUsername,
+            is GroupChatInvite,
             -> true
 
             is Login,
             is EmailVerification,
-            is GroupChatInvite,
             -> false
         }
 }

apps/flipcash/core/src/test/kotlin/com/flipcash/app/core/navigation/DeeplinkScanPolicyTest.kt

@@ -23,6 +23,7 @@ class DeeplinkScanPolicyTest {
         assertTrue(DeeplinkType.TipChat(ChatIdentifier.ByChatId(CHAT_ID)).isScannable)
         assertTrue(DeeplinkType.Tipcard(USER_ID).isScannable)
         assertTrue(DeeplinkType.TipcardByUsername(USERNAME).isScannable)
+        assertTrue(DeeplinkType.GroupChatInvite(CHAT_ID).isScannable)
     }
 
     @Test
@@ -31,17 +32,6 @@ class DeeplinkScanPolicyTest {
         assertFalse(DeeplinkType.EmailVerification(EMAIL, CODE).isScannable)
     }
 
-    /**
-     * Not a security judgement -- an invite is harmless. It is that no scan path has ever opened
-     * one: `Scanner`'s `Navigatable` branch has no case for it and falls to `emptyList()`. Naming
-     * it here keeps that a stated decision rather than a gap, and flipping it means adding the
-     * destination too.
-     */
-    @Test
-    fun `a group chat invite is not a scan destination`() {
-        assertFalse(DeeplinkType.GroupChatInvite(CHAT_ID).isScannable)
-    }
-
     private companion object {
         const val ENTROPY = "0123456789abcdef"
         const val USERNAME = "someone"

apps/flipcash/features/scanner/src/main/kotlin/com/flipcash/app/scanner/internal/Scanner.kt

@@ -25,6 +25,7 @@ import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.flipcash.app.analytics.rememberAnalytics
 import com.flipcash.app.core.AppRoute
 import com.flipcash.app.core.AppRoute.Token.*
+import com.flipcash.app.core.chat.ChatIdentifier
 import com.flipcash.app.core.extensions.navigateAll
 import com.flipcash.app.core.navigation.DeeplinkType
 import com.flipcash.app.core.tipping.TipCardOwner
@@ -119,6 +120,12 @@ internal fun Scanner() {
                         AppRoute.Sheets.Tips(),
                         AppRoute.Messaging.Chat(deeplink.identifier),
                     )
+                    // Same destination as the tapped /chat/{uuid} link: the chat screen is the
+                    // gated preview when the viewer is not yet a member.
+                    is DeeplinkType.GroupChatInvite -> listOf(
+                        AppRoute.Sheets.Tips(),
+                        AppRoute.Messaging.Chat(ChatIdentifier.ByChatId(deeplink.chatId)),
+                    )
                     else -> emptyList()
                 }
                 if (routes.isNotEmpty()) {