Use window.nostr (NIP-46/Amber bunker) on the mobile login page

Replaces the fragile NIP-55 intent/callback round-trip with the same
mechanism the desktop login uses: openNostrLogin signs the session
challenge via window.nostr — provided by an extension or by
window.nostr.js over a persistent NIP-46 connection (Amber pairing with
permissions). The listener stores a LoginKey for the page's k1 and
navigates to the completion route, which issues the token and redirects
into the app via the verified App Link handoff.

resources/views/livewire/auth/mobile-login.blade.php

@@ -1,11 +1,16 @@
 <?php
 
 use App\Http\Controllers\MobileAuthController;
+use App\Jobs\FetchNostrProfileJob;
 use App\Models\LoginKey;
+use App\Support\NostrLogin;
 use App\Traits\SeoTrait;
 use eza\lnurl;
+use Illuminate\Support\Facades\Session;
+use Illuminate\Validation\ValidationException;
 use Livewire\Attributes\Layout;
 use Livewire\Attributes\Locked;
+use Livewire\Attributes\On;
 use Livewire\Component;
 use SimpleSoftwareIO\QrCode\Facades\QrCode;
 
@@ -22,12 +27,13 @@ class extends Component {
     #[Locked]
     public ?string $deviceName = null;
 
+    #[Locked]
+    public ?string $nostrChallenge = null;
+
     public ?string $lnurl = null;
 
     public ?string $qrCode = null;
 
-    public ?string $signerCallbackUrl = null;
-
     public function mount(): void
     {
         $redirectUri = (string) request()->query('redirect_uri', MobileAuthController::ALLOWED_REDIRECT_URIS[0]);
@@ -45,8 +51,8 @@ class extends Component {
             ->value();
 
         // The completion/confirm controller reads the flow state from the
-        // session — the wallet/signer callback arrives outside this session,
-        // so it can't carry the redirect target itself.
+        // session — the wallet callback arrives outside this session, so it
+        // can't carry the redirect target itself.
         session([
             'mobile_auth' => [
                 'redirect_uri' => $this->redirectUri,
@@ -58,14 +64,15 @@ class extends Component {
             return;
         }
 
+        $this->issueNostrChallenge();
         $this->initChallenge();
     }
 
     /**
-     * Generate a fresh k1 challenge shared by both login methods: the
-     * Lightning wallet signs it via LNURL-auth, the Nostr signer puts it
-     * into the challenge tag of a kind-22242 event. Whichever callback
-     * verifies first stores the LoginKey row that checkAuth polls for.
+     * Generate a fresh k1 challenge for the LNURL flow. The Lightning
+     * wallet signs it via LNURL-auth; the resulting LoginKey row is picked
+     * up by checkAuth() below. The Nostr flow reuses the same row keyed by
+     * the same k1 (see loginListener).
      */
     protected function initChallenge(): void
     {
@@ -79,11 +86,6 @@ class extends Component {
 
         $this->lnurl = lnurl\encodeUrl($url);
 
-        // NIP-55 signers append the signed event JSON to the callback URL.
-        // Amber strips query strings when rebuilding the URL, so the k1
-        // travels in the path and the event lands after the trailing slash.
-        $this->signerCallbackUrl = url('/auth/mobile/signed').'/'.$this->k1.'/';
-
         $image = 'public/img/domains/'.session('lang_country', 'de-DE').'.jpg';
         if (! file_exists(base_path($image))) {
             $image = 'public/img/domains/de-DE.jpg';
@@ -96,6 +98,65 @@ class extends Component {
             ->generate($this->lnurl));
     }
 
+    /**
+     * Session-bound challenge for the window.nostr (NIP-07/NIP-46) login —
+     * identical mechanism to the regular login component.
+     */
+    protected function issueNostrChallenge(): string
+    {
+        $challenge = bin2hex(random_bytes(32));
+        $this->nostrChallenge = $challenge;
+        Session::put('nostr_login_challenge', $challenge);
+        Session::put('nostr_login_challenge_expires_at', now()->addSeconds(NostrLogin::CHALLENGE_TTL_SECONDS)->timestamp);
+
+        return $challenge;
+    }
+
+    public function requestNostrChallenge(): string
+    {
+        return $this->issueNostrChallenge();
+    }
+
+    /**
+     * window.nostr signed the kind-22242 challenge (via extension or a
+     * NIP-46 connection to e.g. Amber). Verify it, store the LoginKey and
+     * hand the navigation to the completion route, which issues the token
+     * and redirects into the app via the verified App Link.
+     */
+    #[On('nostrLoggedIn')]
+    public function loginListener($signedEvent = null): void
+    {
+        $npub = $this->verifyNostrLoginEvent($signedEvent);
+
+        $user = NostrLogin::findOrCreateUser($npub);
+
+        FetchNostrProfileJob::dispatch($user);
+
+        LoginKey::query()->updateOrCreate(
+            ['k1' => $this->k1],
+            ['user_id' => $user->id],
+        );
+
+        $this->redirect(route('auth.mobile.complete', ['k1' => $this->k1]));
+    }
+
+    protected function verifyNostrLoginEvent(mixed $signedEvent): string
+    {
+        $expectedChallenge = Session::get('nostr_login_challenge');
+        $expiresAt = (int) Session::get('nostr_login_challenge_expires_at', 0);
+
+        if (! is_string($expectedChallenge) || $expectedChallenge === '' || $expiresAt < now()->timestamp) {
+            Session::forget(['nostr_login_challenge', 'nostr_login_challenge_expires_at']);
+            throw ValidationException::withMessages(['email' => __('auth.failed')]);
+        }
+
+        $npub = NostrLogin::verifyEvent($signedEvent, $expectedChallenge);
+
+        Session::forget(['nostr_login_challenge', 'nostr_login_challenge_expires_at']);
+
+        return $npub;
+    }
+
     public function checkAuth(): void
     {
         $loginKey = LoginKey::query()
@@ -118,6 +179,7 @@ class extends Component {
 
     public function resetAuth(): void
     {
+        $this->issueNostrChallenge();
         $this->initChallenge();
     }
 
@@ -136,8 +198,9 @@ class extends Component {
 ?>
 
 <div class="flex min-h-screen justify-center"
-     x-data="{ loginInProgress: false }"
-     @mobile-login-ready.window="loginInProgress = true; window.location.href = $event.detail.url">
+     x-data="nostrLogin"
+     data-nostr-challenge="{{ $nostrChallenge ?? '' }}"
+     @mobile-login-ready.window="lightningLoginInProgress = true; window.location.href = $event.detail.url">
     <div class="flex justify-center items-center px-4 py-8">
         <div class="w-80 max-w-80 space-y-6">
             <div class="flex justify-center">
@@ -169,28 +232,21 @@ class extends Component {
             @else
                 <flux:heading class="text-center" size="xl">{{ __('Anmelden für die App') }}</flux:heading>
 
-                <!-- Nostr via NIP-55 signer (e.g. Amber) -->
-                <div x-data="{
-                        signWithSigner() {
-                            const event = {
-                                kind: 22242,
-                                created_at: Math.floor(Date.now() / 1000),
-                                content: '',
-                                tags: [['challenge', '{{ $k1 }}']],
-                            };
-                            window.location.href = 'nostrsigner:' + encodeURIComponent(JSON.stringify(event))
-                                + '?compressionType=none&returnType=event&type=sign_event&appName=Einundzwanzig'
-                                + '&callbackUrl=' + encodeURIComponent('{{ $signerCallbackUrl }}');
-                        }
-                     }">
-                    <flux:button variant="primary"
-                                 @click="signWithSigner"
-                                 icon="cursor-arrow-ripple"
-                                 x-bind:disabled="loginInProgress"
-                                 class="w-full cursor-pointer">
-                        {{ __('Log in mit Nostr (Amber)') }}
-                    </flux:button>
-                </div>
+                {{-- Nostr via window.nostr: extension or NIP-46 remote signer
+                     (Amber via bunker/nostrconnect — the window.nostr.js
+                     widget handles pairing and persists the connection). --}}
+                <flux:button variant="primary"
+                             @click="openNostrLogin"
+                             icon="cursor-arrow-ripple"
+                             x-bind:disabled="nostrLoginInProgress"
+                             x-bind:aria-busy="nostrLoginInProgress"
+                             class="w-full cursor-pointer">
+                    <span x-show="!nostrLoginInProgress">{{ __('Log in mit Nostr') }}</span>
+                    <span x-show="nostrLoginInProgress" x-cloak class="inline-flex items-center gap-2">
+                        <flux:icon.arrow-path class="animate-spin size-4" aria-hidden="true"/>
+                        {{ __('Signiere…') }}
+                    </span>
+                </flux:button>
 
                 <div class="text-center text-2xl text-gray-80 dark:text-gray-2000 mt-2">
                     {{ __('Login with lightning ⚡') }}
@@ -217,13 +273,13 @@ class extends Component {
                     </flux:button>
                 </div>
 
-                {{-- Poll for the LoginKey row written by either callback.
-                     Paused while the completion navigation is in flight. --}}
-                <template x-if="!loginInProgress">
+                {{-- Poll for the LoginKey row written by the LNURL callback.
+                     Paused while a login round-trip or navigation is in flight. --}}
+                <template x-if="!nostrLoginInProgress && !lightningLoginInProgress">
                     <div wire:poll.4s="checkAuth" wire:key="checkAuth"></div>
                 </template>
 
-                <div x-show="loginInProgress" x-cloak class="flex items-center justify-center gap-2">
+                <div x-show="lightningLoginInProgress" x-cloak class="flex items-center justify-center gap-2">
                     <flux:icon.arrow-path class="animate-spin size-4" aria-hidden="true"/>
                     <flux:text>{{ __('Anmeldung wird abgeschlossen…') }}</flux:text>
                 </div>

tests/Feature/Auth/MobileAuthTest.php

@@ -201,6 +201,27 @@ it('lets an already authenticated user connect the app and replaces tokens of th
     expect($user->tokens()->where('name', 'Pixel 10')->count())->toBe(1);
 });
 
+it('completes a window.nostr login on the mobile page via LoginKey and the completion route', function () {
+    Queue::fake();
+
+    $component = Livewire\Livewire::withQueryParams(['redirect_uri' => 'einundzwanzig://auth', 'device_name' => 'Pixel 10'])
+        ->test('auth.mobile-login');
+
+    // Helper from NostrLoginTest: signs the challenge stored in the session.
+    [$signedEvent, $npub] = makeSignedNostrLoginEvent();
+
+    $k1 = $component->get('k1');
+
+    $component
+        ->dispatch('nostrLoggedIn', signedEvent: $signedEvent)
+        ->assertRedirect(route('auth.mobile.complete', ['k1' => $k1]));
+
+    $user = User::query()->where('nostr', $npub)->first();
+    expect($user)->not->toBeNull();
+    expect(LoginKey::query()->where('k1', $k1)->value('user_id'))->toBe($user->id);
+    Queue::assertPushed(FetchNostrProfileJob::class);
+});
+
 it('shows the confirmation screen instead of the login methods for authenticated users', function () {
     $user = User::factory()->create();