feat(nip46): scan nostrconnect:// from anywhere and un-gate the connect flow

Two UX gaps made "scan an app's code to connect it to my signer" hard to
reach:

- The signer screen's Connect section (Scan a code / paste) lived behind
  the enabled gate, so a first-time user saw only the "Turn on signer"
  hero and couldn't scan until they had enabled. Since a successful
  nostrconnect pairing already calls setEnabled(true), the gate was
  pointless. The Connect section now shows in both states; the success
  toast spells out the consequence ("Amethyst now signs for it in the
  background").
- The app's general QR scanner (uriToRoute) only understood NIP-19
  entities, so scanning a nostrconnect:// code did nothing. It now routes
  a nostrconnect:// offer to the signer screen, which pairs the app on
  open. Route.Nip46Signer carries an optional connectUri for this.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015FHr2mu5SiHwYNR7evYUuF

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/MainActivity.kt

@@ -53,6 +53,7 @@ import com.vitorpamplona.quartz.nip19Bech32.entities.NPub
 import com.vitorpamplona.quartz.nip29RelayGroups.GroupInviteLink
 import com.vitorpamplona.quartz.nip29RelayGroups.GroupNAddrInvite
 import com.vitorpamplona.quartz.nip29RelayGroups.metadata.GroupMetadataEvent
+import com.vitorpamplona.quartz.nip46RemoteSigner.NostrConnectURI
 import com.vitorpamplona.quartz.nip47WalletConnect.Nip47WalletConnect
 import com.vitorpamplona.quartz.nip52Calendar.appt.day.CalendarDateSlotEvent
 import com.vitorpamplona.quartz.nip52Calendar.appt.time.CalendarTimeSlotEvent
@@ -224,6 +225,12 @@ fun uriToRoute(
         return connectedAppRoute(uri)
     }
 
+    // A scanned/opened `nostrconnect://` offer is an app asking to connect to our signer: open the
+    // NIP-46 signer screen and let it run the pairing (it enables the signer as part of connecting).
+    if (uri.startsWith(NostrConnectURI.NOSTRCONNECT_SCHEME)) {
+        return Route.Nip46Signer(connectUri = uri)
+    }
+
     relayGroupInviteRoute(uri)?.let { return it }
     concordInviteRoute(uri)?.let { return it }
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/AppNavigation.kt

@@ -424,7 +424,7 @@ fun BuildNavigation(
         composableFromEndArgs<Route.NostrApp>(capWidth = false) { NostrAppScreen(it.coordinate, accountViewModel, nav) }
         composableFromEnd<Route.ConnectedApps> { ConnectedAppsScreen(accountViewModel, nav) }
         composableFromEndArgs<Route.ConnectedAppDetail> { ConnectedAppDetailScreen(it.coordinate, accountViewModel, nav) }
-        composableFromEnd<Route.Nip46Signer> { Nip46SignerScreen(accountViewModel, nav) }
+        composableFromEndArgs<Route.Nip46Signer> { Nip46SignerScreen(accountViewModel, nav, it.connectUri) }
         composableFromEnd<Route.RelayAuthSettings> { RelayAuthSettingsScreen(accountViewModel, nav) }
         composableFromEndArgs<Route.SoftwareAppDetail> { SoftwareAppDetailScreen(Address(it.kind, it.pubKeyHex, it.dTag), accountViewModel, nav) }
         composableFromEnd<Route.Calendars> { CalendarsScreen(accountViewModel, nav) }

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/navigation/routes/Routes.kt

@@ -107,7 +107,10 @@ sealed class Route {
 
     @Serializable object ConnectedApps : Route()
 
-    @Serializable object Nip46Signer : Route()
+    @Serializable data class Nip46Signer(
+        /** When set (from a scanned/opened `nostrconnect://` offer), the screen connects that app on open. */
+        val connectUri: String? = null,
+    ) : Route()
 
     @Serializable object RelayAuthSettings : Route()
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/settings/SettingsCatalogBuilder.kt

@@ -75,7 +75,7 @@ fun buildSettingsCatalog(
                     symEntry(R.string.profile_badges_title, MaterialSymbols.MilitaryTech, R.string.profile_badges_search_keywords, Route.ProfileBadges),
                     symEntry(R.string.payment_targets, MaterialSymbols.Payment, R.string.payment_targets_search_keywords, Route.EditPaymentTargets),
                     symEntry(R.string.napplet_permissions_title, MaterialSymbols.Apps, R.string.napplet_connected_apps_search_keywords, Route.ConnectedApps),
-                    symEntry(R.string.nip46_signer_title, MaterialSymbols.Key, R.string.nip46_signer_search_keywords, Route.Nip46Signer),
+                    symEntry(R.string.nip46_signer_title, MaterialSymbols.Key, R.string.nip46_signer_search_keywords, Route.Nip46Signer()),
                     symEntry(R.string.relay_auth_settings_title, MaterialSymbols.Lock, R.string.relay_auth_search_keywords, Route.RelayAuthSettings),
                     symEntry(R.string.security_filters, MaterialSymbols.Security, R.string.security_filters_search_keywords, Route.SecurityFilters),
                     symEntry(R.string.call_settings, MaterialSymbols.Phone, R.string.call_settings_search_keywords, Route.CallSettings),

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/settings/nip46/Nip46SignerScreen.kt

@@ -101,6 +101,7 @@ private val LiveGreen = Color(0xFF3DDC84)
 fun Nip46SignerScreen(
     accountViewModel: AccountViewModel,
     nav: INav,
+    connectUri: String? = null,
 ) {
     val account = accountViewModel.account
     val signer = account.nip46Signer
@@ -138,6 +139,11 @@ fun Nip46SignerScreen(
         }
     }
 
+    // Opened from a scanned/shared nostrconnect:// offer — pair that app on open (this also enables the signer).
+    LaunchedEffect(connectUri) {
+        if (!connectUri.isNullOrBlank()) onConnect(connectUri)
+    }
+
     if (scanning) {
         SimpleQrCodeScanner { contents ->
             scanning = false
@@ -162,47 +168,52 @@ fun Nip46SignerScreen(
                 return@Column
             }
 
-            if (!enabled) {
-                DisabledHero(onEnable = { signer.setEnabled(true) })
-                return@Column
-            }
-
-            LiveStatusCard(
-                relayCount = relays.size,
-                connectedCount = connectedCount,
-                onToggleOff = { signer.setEnabled(false) },
-            )
-
-            if (relays.isEmpty()) {
-                WarningCard(stringResource(R.string.nip46_signer_status_no_relays))
-            }
-
-            bunkerUri?.let { uri ->
-                QrHeroCard(
-                    uri = uri,
-                    onCopy = {
-                        clipboard.setText(AnnotatedString(uri))
-                        Toast.makeText(context, R.string.nip46_signer_copied, Toast.LENGTH_SHORT).show()
-                    },
-                    onRegenerate = { confirmRotate = true },
+            if (enabled) {
+                LiveStatusCard(
+                    relayCount = relays.size,
+                    connectedCount = connectedCount,
+                    onToggleOff = { signer.setEnabled(false) },
                 )
+
+                if (relays.isEmpty()) {
+                    WarningCard(stringResource(R.string.nip46_signer_status_no_relays))
+                }
+
+                bunkerUri?.let { uri ->
+                    QrHeroCard(
+                        uri = uri,
+                        onCopy = {
+                            clipboard.setText(AnnotatedString(uri))
+                            Toast.makeText(context, R.string.nip46_signer_copied, Toast.LENGTH_SHORT).show()
+                        },
+                        onRegenerate = { confirmRotate = true },
+                    )
+                }
+            } else {
+                DisabledHero(onEnable = { signer.setEnabled(true) })
             }
 
+            // The Connect section stays reachable even while off: scanning an app's nostrconnect://
+            // code pairs it and enables the signer as part of connecting (no separate "enable" step).
             ConnectSection(
                 onScan = { scanning = true },
                 onPaste = { onConnect(it) },
             )
 
-            ConnectedAppsRow(
-                count = connectedCount,
-                onClick = { nav.nav(Route.ConnectedApps) },
-            )
+            if (enabled || connectedCount > 0) {
+                ConnectedAppsRow(
+                    count = connectedCount,
+                    onClick = { nav.nav(Route.ConnectedApps) },
+                )
+            }
 
-            Text(
-                stringResource(R.string.nip46_signer_background_hint),
-                style = MaterialTheme.typography.labelSmall,
-                color = MaterialTheme.colorScheme.onSurfaceVariant,
-            )
+            if (enabled) {
+                Text(
+                    stringResource(R.string.nip46_signer_background_hint),
+                    style = MaterialTheme.typography.labelSmall,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                )
+            }
         }
     }
 

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

@@ -923,8 +923,8 @@
     <string name="nip46_signer_connect_hint">Paste a nostrconnect:// link</string>
     <string name="nip46_signer_connect_button">Connect</string>
     <string name="nip46_signer_manage_apps">Manage connected apps</string>
-    <string name="nip46_signer_connected_ok">App connected</string>
-    <string name="nip46_signer_connected_named">Connected %1$s</string>
+    <string name="nip46_signer_connected_ok">App connected. Amethyst now signs for it in the background.</string>
+    <string name="nip46_signer_connected_named">Connected %1$s. Amethyst now signs for it in the background.</string>
     <string name="nip46_signer_connect_invalid">Not a valid nostrconnect:// link</string>
     <string name="nip46_signer_connect_no_relays">That link carries no relay to connect on</string>
     <string name="nip46_signer_connect_failed">Could not connect: %1$s</string>

amethyst/src/test/java/com/vitorpamplona/amethyst/ui/UriToRouteTest.kt

@@ -58,6 +58,12 @@ class UriToRouteTest {
         assertEquals(Route.Hashtag("foo"), uriToRoute("nostr:hashtag?id=foo", account))
     }
 
+    @Test
+    fun nostrConnectOfferRoutesToTheSignerScreenCarryingTheUri() {
+        val offer = "nostrconnect://" + "b".repeat(64) + "?relay=wss%3A%2F%2Frelay.example.com&secret=abc123"
+        assertEquals(Route.Nip46Signer(connectUri = offer), uriToRoute(offer, account))
+    }
+
     @Test
     fun fragmentHashtagOrNullExtractsTheTag() {
         assertEquals("NostrMultiplayerGames", fragmentHashtagOrNull("#NostrMultiplayerGames"))