chore: update version number to 0.1.36

VERSION

@@ -1 +1 @@
-0.1.35
+0.1.36

app.config.js

@@ -20,6 +20,7 @@ module.exports = {
   expo: {
     name: 'Bulwark Mobile',
     slug: 'bulwark-mobile',
+    scheme: 'bulwarkmobile',
     version: VERSION,
     orientation: 'portrait',
     icon: './assets/icon.png',

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "bulwark-mobile",
-  "version": "0.1.35",
+  "version": "0.1.36",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "bulwark-mobile",
-      "version": "0.1.35",
+      "version": "0.1.36",
       "license": "AGPL-3.0-only",
       "dependencies": {
         "@react-native-async-storage/async-storage": "2.2.0",
@@ -17,6 +17,8 @@
         "@react-navigation/native-stack": "^7.14.10",
         "date-fns": "^4.1.0",
         "expo": "~54.0.33",
+        "expo-auth-session": "~7.0.8",
+        "expo-crypto": "~15.0.7",
         "expo-document-picker": "~14.0.8",
         "expo-file-system": "~19.0.21",
         "expo-image-picker": "~17.0.10",
@@ -25,6 +27,7 @@
         "expo-secure-store": "~15.0.8",
         "expo-sharing": "~14.0.8",
         "expo-status-bar": "~3.0.9",
+        "expo-web-browser": "~15.0.8",
         "lucide-react-native": "^1.7.0",
         "react": "19.1.0",
         "react-native": "0.81.5",
@@ -5203,6 +5206,33 @@
         }
       }
     },
+    "node_modules/expo-auth-session": {
+      "version": "7.0.11",
+      "resolved": "https://registry.npmjs.org/expo-auth-session/-/expo-auth-session-7.0.11.tgz",
+      "integrity": "sha512-AhWtt/m9rb1Po77X/VBFbeE6UTgbm2vXP2iCblUSRsHCw2qD6lO0ulKUB8Xyxy9FtoI9yrNQ1iwCNgIIgo8VYQ==",
+      "license": "MIT",
+      "dependencies": {
+        "expo-application": "~7.0.8",
+        "expo-constants": "~18.0.13",
+        "expo-crypto": "~15.0.9",
+        "expo-linking": "~8.0.12",
+        "expo-web-browser": "~15.0.11",
+        "invariant": "^2.2.4"
+      },
+      "peerDependencies": {
+        "react": "*",
+        "react-native": "*"
+      }
+    },
+    "node_modules/expo-auth-session/node_modules/expo-application": {
+      "version": "7.0.8",
+      "resolved": "https://registry.npmjs.org/expo-application/-/expo-application-7.0.8.tgz",
+      "integrity": "sha512-qFGyxk7VJbrNOQWBbE09XUuGuvkOgFS9QfToaK2FdagM2aQ+x3CvGV2DuVgl/l4ZxPgIf3b/MNh9xHpwSwn74Q==",
+      "license": "MIT",
+      "peerDependencies": {
+        "expo": "*"
+      }
+    },
     "node_modules/expo-constants": {
       "version": "18.0.13",
       "resolved": "https://registry.npmjs.org/expo-constants/-/expo-constants-18.0.13.tgz",
@@ -5217,6 +5247,18 @@
         "react-native": "*"
       }
     },
+    "node_modules/expo-crypto": {
+      "version": "15.0.9",
+      "resolved": "https://registry.npmjs.org/expo-crypto/-/expo-crypto-15.0.9.tgz",
+      "integrity": "sha512-SNWKa2fXx7v9gkp1h/7nqXY5XN7qgNDn3yRc2aO0gWGbeMbvob/haMxxsPFe9f51aqH5NjNCqHf2kvLhvAd8KQ==",
+      "license": "MIT",
+      "dependencies": {
+        "base64-js": "^1.3.0"
+      },
+      "peerDependencies": {
+        "expo": "*"
+      }
+    },
     "node_modules/expo-document-picker": {
       "version": "14.0.8",
       "resolved": "https://registry.npmjs.org/expo-document-picker/-/expo-document-picker-14.0.8.tgz",
@@ -5266,6 +5308,20 @@
         "expo": "*"
       }
     },
+    "node_modules/expo-linking": {
+      "version": "8.0.12",
+      "resolved": "https://registry.npmjs.org/expo-linking/-/expo-linking-8.0.12.tgz",
+      "integrity": "sha512-FpXeIpFgZuxihwT9lBo86YD3y6LphBuAhN680MMxm/Y7fmsc57vimn2d3vFu68VI0+Z9w457t494mu2wvlgWTQ==",
+      "license": "MIT",
+      "dependencies": {
+        "expo-constants": "~18.0.13",
+        "invariant": "^2.2.4"
+      },
+      "peerDependencies": {
+        "react": "*",
+        "react-native": "*"
+      }
+    },
     "node_modules/expo-localization": {
       "version": "17.0.8",
       "resolved": "https://registry.npmjs.org/expo-localization/-/expo-localization-17.0.8.tgz",
@@ -5418,6 +5474,16 @@
         "react-native": "*"
       }
     },
+    "node_modules/expo-web-browser": {
+      "version": "15.0.11",
+      "resolved": "https://registry.npmjs.org/expo-web-browser/-/expo-web-browser-15.0.11.tgz",
+      "integrity": "sha512-r2LS4Ro6DgUPZkcaEfgt8mp9eJuoA93x11Jh7S6utFe0FEzvUNn2yFhxg8XVwESaaHGt2k5V8LuK36rsp0BeIw==",
+      "license": "MIT",
+      "peerDependencies": {
+        "expo": "*",
+        "react-native": "*"
+      }
+    },
     "node_modules/expo/node_modules/@babel/code-frame": {
       "version": "7.29.0",
       "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.29.0.tgz",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "bulwark-mobile",
-  "version": "0.1.35",
+  "version": "0.1.36",
   "license": "AGPL-3.0-only",
   "main": "index.ts",
   "scripts": {
@@ -23,6 +23,8 @@
     "@react-navigation/native-stack": "^7.14.10",
     "date-fns": "^4.1.0",
     "expo": "~54.0.33",
+    "expo-auth-session": "~7.0.8",
+    "expo-crypto": "~15.0.7",
     "expo-document-picker": "~14.0.8",
     "expo-file-system": "~19.0.21",
     "expo-image-picker": "~17.0.10",
@@ -31,6 +33,7 @@
     "expo-secure-store": "~15.0.8",
     "expo-sharing": "~14.0.8",
     "expo-status-bar": "~3.0.9",
+    "expo-web-browser": "~15.0.8",
     "lucide-react-native": "^1.7.0",
     "react": "19.1.0",
     "react-native": "0.81.5",

src/api/jmap-client.ts

@@ -8,6 +8,11 @@ import type {
 import { CAPABILITIES } from './types';
 import { generateAccountId } from '../lib/account-utils';
 import { secureFetch } from '../lib/client-cert';
+import { refreshAccessToken, type OAuthTokens } from '../lib/oauth';
+
+// Refresh OAuth access tokens this many ms before they actually expire so
+// in-flight requests don't race the expiry window.
+const TOKEN_REFRESH_LEEWAY_MS = 60_000;
 
 const LEGACY_CREDENTIALS_KEY = 'jmap_credentials';
 const CREDENTIALS_PREFIX = 'jmap_credentials__';
@@ -22,6 +27,12 @@ export interface StoredCredentials {
   username: string;
   password: string;
   accessToken?: string;
+  // OAuth-only — present when credentials originate from the OAuth login
+  // flow rather than password auth.
+  refreshToken?: string;
+  expiresAt?: number;
+  tokenEndpoint?: string;
+  clientId?: string;
 }
 
 export class JMAPClient {
@@ -93,6 +104,115 @@ export class JMAPClient {
     return this.session;
   }
 
+  // OAuth login. Fetches the JMAP session to discover the authenticated
+  // username from the session.username field, persists credentials under that
+  // username's account id, and returns both the session and the resolved
+  // username so the auth-store can register the account.
+  async connectWithOAuth(
+    serverUrl: string,
+    tokens: OAuthTokens,
+  ): Promise<{ session: JMAPSession; username: string; accountId: string }> {
+    const baseUrl = serverUrl.replace(/\/+$/, '');
+    this.credentials = {
+      serverUrl: baseUrl,
+      username: '',
+      password: '',
+      accessToken: tokens.accessToken,
+      refreshToken: tokens.refreshToken,
+      expiresAt: tokens.expiresAt,
+      tokenEndpoint: tokens.tokenEndpoint,
+      clientId: tokens.clientId,
+    };
+
+    this.session = this.rewriteSessionUrls(await this.fetchSession(baseUrl), baseUrl);
+    this._accountId = this.resolveAccountId(this.session);
+
+    // The JMAP session document carries the authenticated user's identifier
+    // — use it as the username so per-account storage keys are stable across
+    // restarts and OAuth re-logins.
+    const username = this.session.username || tokens.accessToken.slice(0, 8);
+    this.credentials.username = username;
+
+    const accountId = generateAccountId(username, baseUrl);
+    await SecureStore.setItemAsync(
+      credentialsKey(accountId),
+      JSON.stringify(this.credentials),
+    );
+
+    return { session: this.session, username, accountId };
+  }
+
+  // Replace the access token (and possibly refresh token) on the in-memory
+  // credentials and re-persist. Used both by the proactive expiry check and
+  // by the reactive 401-retry path.
+  private async persistRefreshedTokens(next: OAuthTokens): Promise<void> {
+    if (!this.credentials) return;
+    this.credentials = {
+      ...this.credentials,
+      accessToken: next.accessToken,
+      refreshToken: next.refreshToken ?? this.credentials.refreshToken,
+      expiresAt: next.expiresAt,
+      tokenEndpoint: next.tokenEndpoint,
+      clientId: next.clientId,
+    };
+    const accountId = generateAccountId(
+      this.credentials.username,
+      this.credentials.serverUrl,
+    );
+    await SecureStore.setItemAsync(
+      credentialsKey(accountId),
+      JSON.stringify(this.credentials),
+    );
+  }
+
+  private hasRefreshableToken(): boolean {
+    return Boolean(this.credentials?.refreshToken && this.credentials.tokenEndpoint && this.credentials.clientId);
+  }
+
+  private currentOAuthTokens(): OAuthTokens | null {
+    if (!this.credentials?.accessToken || !this.credentials.tokenEndpoint || !this.credentials.clientId) {
+      return null;
+    }
+    return {
+      accessToken: this.credentials.accessToken,
+      refreshToken: this.credentials.refreshToken,
+      expiresAt: this.credentials.expiresAt,
+      tokenEndpoint: this.credentials.tokenEndpoint,
+      clientId: this.credentials.clientId,
+    };
+  }
+
+  // Refresh proactively when we're within the leeway window of expiry. Quiet
+  // no-op for password credentials or when the token is still fresh.
+  private async ensureFreshToken(): Promise<void> {
+    const tokens = this.currentOAuthTokens();
+    if (!tokens) return;
+    if (!this.hasRefreshableToken()) return;
+    if (tokens.expiresAt == null) return;
+    if (tokens.expiresAt - Date.now() > TOKEN_REFRESH_LEEWAY_MS) return;
+    try {
+      const next = await refreshAccessToken(tokens);
+      await this.persistRefreshedTokens(next);
+    } catch {
+      // Surface as AuthenticationError on the next 401; refresh may be
+      // temporarily failing (network) and that path already retries.
+    }
+  }
+
+  // Reactive refresh: called after a 401 to attempt a single retry with a
+  // freshly-minted access token. Returns true if a new token was obtained.
+  private async forceRefreshToken(): Promise<boolean> {
+    const tokens = this.currentOAuthTokens();
+    if (!tokens || !this.hasRefreshableToken()) return false;
+    try {
+      const next = await refreshAccessToken(tokens);
+      await this.persistRefreshedTokens(next);
+      return true;
+    } catch {
+      return false;
+    }
+  }
+
   // Legacy single-slot restore - kept for backward-compat tests. New code
   // should use loadAccount(accountId) driven by the account registry.
   async restoreSession(): Promise<boolean> {
@@ -235,13 +355,23 @@ export class JMAPClient {
 
   private async fetchSession(baseUrl: string): Promise<JMAPSession> {
     const url = `${baseUrl}/.well-known/jmap`;
-    const response = await secureFetch(url, {
+    await this.ensureFreshToken();
+    let response = await secureFetch(url, {
       headers: {
         Authorization: this.authHeader,
         Accept: 'application/json',
       },
     });
 
+    if (response.status === 401 && (await this.forceRefreshToken())) {
+      response = await secureFetch(url, {
+        headers: {
+          Authorization: this.authHeader,
+          Accept: 'application/json',
+        },
+      });
+    }
+
     if (response.status === 401) {
       throw new AuthenticationError('Invalid credentials');
     }
@@ -280,14 +410,21 @@ export class JMAPClient {
       methodCalls,
     };
 
-    const response = await secureFetch(this.session.apiUrl, {
-      method: 'POST',
-      headers: {
-        'Content-Type': 'application/json',
-        Authorization: this.authHeader,
-      },
-      body: JSON.stringify(body),
-    });
+    await this.ensureFreshToken();
+    const doFetch = () =>
+      secureFetch(this.session!.apiUrl, {
+        method: 'POST',
+        headers: {
+          'Content-Type': 'application/json',
+          Authorization: this.authHeader,
+        },
+        body: JSON.stringify(body),
+      });
+
+    let response = await doFetch();
+    if (response.status === 401 && (await this.forceRefreshToken())) {
+      response = await doFetch();
+    }
 
     if (response.status === 401) {
       throw new AuthenticationError('Session expired');
@@ -335,9 +472,12 @@ export class JMAPClient {
 
   async fetchBlobArrayBuffer(blobId: string, name?: string, type?: string): Promise<ArrayBuffer> {
     const url = this.getBlobDownloadUrl(blobId, name, type);
-    const response = await secureFetch(url, {
-      headers: { Authorization: this.authHeader },
-    });
+    await this.ensureFreshToken();
+    const doFetch = () => secureFetch(url, { headers: { Authorization: this.authHeader } });
+    let response = await doFetch();
+    if (response.status === 401 && (await this.forceRefreshToken())) {
+      response = await doFetch();
+    }
     if (response.status === 401) throw new AuthenticationError('Session expired');
     if (!response.ok) throw new Error(`Failed to fetch blob: ${response.status}`);
     return response.arrayBuffer();

src/api/types.ts

@@ -9,6 +9,10 @@ export interface JMAPSession {
   accounts: Record<string, JMAPAccountInfo>;
   capabilities: Record<string, unknown>;
   state: string;
+  // RFC 8620 §2 — authenticated user identifier. Optional because not all
+  // servers populate it; OAuth login uses it to derive the account label
+  // when there's no password username to fall back on.
+  username?: string;
 }
 
 export interface JMAPAccountInfo {

src/lib/oauth.ts

@@ -0,0 +1,157 @@
+import * as AuthSession from 'expo-auth-session';
+import * as WebBrowser from 'expo-web-browser';
+import { secureFetch } from './client-cert';
+
+// OAuth client ID registered (or accepted unregistered, when the server has
+// requireClientRegistration=false like Stalwart 0.16) for the mobile app.
+export const OAUTH_CLIENT_ID = 'bulwark-mobile';
+
+// offline_access is required for Stalwart to return a refresh_token; without
+// it the session dies as soon as the access token expires.
+export const OAUTH_SCOPES = ['openid', 'email', 'profile', 'offline_access'];
+
+export interface OAuthDiscovery {
+  authorization_endpoint: string;
+  token_endpoint: string;
+  revocation_endpoint?: string;
+}
+
+export interface OAuthTokens {
+  accessToken: string;
+  refreshToken?: string;
+  expiresAt?: number; // epoch ms
+  tokenEndpoint: string;
+  clientId: string;
+}
+
+export class OAuthError extends Error {}
+export class OAuthCancelledError extends OAuthError {
+  constructor() {
+    super('OAuth cancelled');
+  }
+}
+
+export async function discoverOAuth(serverUrl: string): Promise<OAuthDiscovery> {
+  const baseUrl = serverUrl.replace(/\/+$/, '');
+  const urls = [
+    `${baseUrl}/.well-known/oauth-authorization-server`,
+    `${baseUrl}/.well-known/openid-configuration`,
+  ];
+  const errors: string[] = [];
+  for (const url of urls) {
+    try {
+      const res = await secureFetch(url, { headers: { Accept: 'application/json' } });
+      if (!res.ok) {
+        errors.push(`${url} → HTTP ${res.status}`);
+        continue;
+      }
+      const data = await res.json();
+      if (data.authorization_endpoint && data.token_endpoint) {
+        return {
+          authorization_endpoint: data.authorization_endpoint,
+          token_endpoint: data.token_endpoint,
+          revocation_endpoint: data.revocation_endpoint,
+        };
+      }
+      errors.push(`${url} missing endpoints`);
+    } catch (err) {
+      errors.push(`${url}: ${err instanceof Error ? err.message : String(err)}`);
+    }
+  }
+  throw new OAuthError(`OAuth discovery failed: ${errors.join('; ')}`);
+}
+
+// Returns the redirect URI the browser will land on after the user signs in.
+// For dev (Expo Go) this is the auth.expo.io proxy; for standalone/prebuild
+// builds this is the app's custom scheme (bulwarkmobile://auth/callback).
+function getRedirectUri(): string {
+  return AuthSession.makeRedirectUri({ scheme: 'bulwarkmobile', path: 'auth/callback' });
+}
+
+export async function runOAuthFlow(serverUrl: string): Promise<OAuthTokens> {
+  const discovery = await discoverOAuth(serverUrl);
+  const redirectUri = getRedirectUri();
+
+  const request = new AuthSession.AuthRequest({
+    clientId: OAUTH_CLIENT_ID,
+    scopes: OAUTH_SCOPES,
+    redirectUri,
+    responseType: AuthSession.ResponseType.Code,
+    usePKCE: true,
+  });
+
+  // promptAsync() opens the system browser tab and resolves when the OAuth
+  // server redirects back to the app via the custom scheme.
+  const result = await request.promptAsync({
+    authorizationEndpoint: discovery.authorization_endpoint,
+  });
+
+  if (result.type === 'cancel' || result.type === 'dismiss') {
+    throw new OAuthCancelledError();
+  }
+  if (result.type !== 'success') {
+    const msg =
+      result.type === 'error' && result.error
+        ? result.error.description || result.error.message || result.type
+        : result.type;
+    throw new OAuthError(`Authorization failed: ${msg}`);
+  }
+  const code = result.params.code;
+  if (!code) throw new OAuthError('Authorization response missing code');
+
+  // Exchange the authorization code for tokens. Stalwart returns a JSON body
+  // with access_token, refresh_token, expires_in.
+  const tokenResult = await AuthSession.exchangeCodeAsync(
+    {
+      clientId: OAUTH_CLIENT_ID,
+      code,
+      redirectUri,
+      extraParams: request.codeVerifier ? { code_verifier: request.codeVerifier } : undefined,
+    },
+    { tokenEndpoint: discovery.token_endpoint },
+  );
+
+  return {
+    accessToken: tokenResult.accessToken,
+    refreshToken: tokenResult.refreshToken,
+    expiresAt:
+      tokenResult.expiresIn != null
+        ? Date.now() + tokenResult.expiresIn * 1000
+        : undefined,
+    tokenEndpoint: discovery.token_endpoint,
+    clientId: OAUTH_CLIENT_ID,
+  };
+}
+
+export async function refreshAccessToken(
+  tokens: OAuthTokens,
+): Promise<OAuthTokens> {
+  if (!tokens.refreshToken) {
+    throw new OAuthError('No refresh token available');
+  }
+  const refreshed = await AuthSession.refreshAsync(
+    { clientId: tokens.clientId, refreshToken: tokens.refreshToken },
+    { tokenEndpoint: tokens.tokenEndpoint },
+  );
+  return {
+    accessToken: refreshed.accessToken,
+    // Rotated refresh tokens replace the previous one; some IdPs omit it and
+    // expect the client to reuse the original.
+    refreshToken: refreshed.refreshToken ?? tokens.refreshToken,
+    expiresAt:
+      refreshed.expiresIn != null
+        ? Date.now() + refreshed.expiresIn * 1000
+        : undefined,
+    tokenEndpoint: tokens.tokenEndpoint,
+    clientId: tokens.clientId,
+  };
+}
+
+// Required to dismiss the in-app browser tab once the OAuth redirect fires.
+// Safe to call once at module load; expo-web-browser exposes it via a method
+// that no-ops on platforms where it isn't needed.
+export function warmUpAuthBrowser(): void {
+  void WebBrowser.warmUpAsync().catch(() => undefined);
+}
+
+WebBrowser.maybeCompleteAuthSession();

src/screens/LoginScreen.tsx

@@ -20,6 +20,7 @@ export default function LoginScreen({ onLogin, isAddMode, onCancel }: LoginScree
   const c = useColors();
   const styles = React.useMemo(() => makeStyles(c), [c]);
   const login = useAuthStore((state) => state.login);
+  const loginOAuth = useAuthStore((state) => state.loginOAuth);
   const isLoading = useAuthStore((state) => state.isLoading);
   const error = useAuthStore((state) => state.error);
   const clearError = useAuthStore((state) => state.clearError);
@@ -30,6 +31,7 @@ export default function LoginScreen({ onLogin, isAddMode, onCancel }: LoginScree
   const [showPassword, setShowPassword] = React.useState(false);
 
   const canSubmit = Boolean(serverUrl.trim() && email.trim() && password);
+  const canOAuth = Boolean(serverUrl.trim());
 
   const handleLogin = async () => {
     if (!canSubmit) {
@@ -44,6 +46,24 @@ export default function LoginScreen({ onLogin, isAddMode, onCancel }: LoginScree
     }
   };
 
+  const handleOAuth = async () => {
+    if (!canOAuth) return;
+    try {
+      const before = useAuthStore.getState().isAuthenticated;
+      await loginOAuth(serverUrl.trim(), { addAccount: isAddMode });
+      // loginOAuth swallows OAuthCancelledError silently — only fire the
+      // navigation hook when authentication actually completed.
+      const after = useAuthStore.getState().isAuthenticated;
+      if (after && !before) {
+        onLogin?.();
+      } else if (isAddMode && after) {
+        onLogin?.();
+      }
+    } catch {
+      // Store state already contains the user-facing error.
+    }
+  };
+
   const updateField = React.useCallback(
     (setter: React.Dispatch<React.SetStateAction<string>>) => (value: string) => {
       if (useAuthStore.getState().error) {
@@ -151,8 +171,15 @@ export default function LoginScreen({ onLogin, isAddMode, onCancel }: LoginScree
 
             {/* OAuth buttons */}
             <View style={styles.oauthRow}>
-              <Button variant="outline" size="md" disabled>
-                SSO Provider
+              <Button
+                variant="outline"
+                size="md"
+                onPress={() => {
+                  void handleOAuth();
+                }}
+                disabled={!canOAuth || isLoading}
+              >
+                Sign in with OAuth
               </Button>
             </View>
           </View>

src/stores/auth-store.ts

@@ -6,6 +6,7 @@ import { useEmailStore } from './email-store';
 import { useContactsStore } from './contacts-store';
 import { useCalendarStore } from './calendar-store';
 import { generateAccountId } from '../lib/account-utils';
+import { runOAuthFlow, OAuthCancelledError } from '../lib/oauth';
 import {
   teardownPushNotifications,
   teardownPushNotificationsForAccount,
@@ -38,6 +39,7 @@ export interface AuthState {
   client: typeof jmapClient | null;
 
   login: (serverUrl: string, username: string, password: string, opts?: { addAccount?: boolean }) => Promise<void>;
+  loginOAuth: (serverUrl: string, opts?: { addAccount?: boolean }) => Promise<void>;
   logout: () => Promise<void>;
   logoutAll: () => Promise<void>;
   switchAccount: (accountId: string) => Promise<void>;
@@ -167,6 +169,51 @@ export const useAuthStore = create<AuthState>((set, get) => ({
     }
   },
 
+  loginOAuth: async (serverUrl, opts) => {
+    set({ isLoading: true, error: null });
+    try {
+      if (opts?.addAccount && get().isAuthenticated) {
+        jmapClient.reset();
+        useContactsStore.getState().reset();
+        useCalendarStore.getState().reset();
+      }
+
+      const baseUrl = serverUrl.replace(/\/+$/, '');
+      const tokens = await runOAuthFlow(baseUrl);
+      const { session, username, accountId } = await jmapClient.connectWithOAuth(baseUrl, tokens);
+
+      const accountStore = useAccountStore.getState();
+      accountStore.addAccount({
+        serverUrl: baseUrl,
+        username,
+        displayName: username,
+        email: username,
+        lastLoginAt: Date.now(),
+        isConnected: true,
+        hasError: false,
+      });
+      accountStore.setActiveAccount(accountId);
+      useEmailStore.getState().setActiveAccount(accountId);
+
+      applyConnectedState(set, session, baseUrl, username, accountId);
+    } catch (err) {
+      if (err instanceof OAuthCancelledError) {
+        // User backed out of the browser tab — no error message, just stop
+        // the spinner. This matches the common "I changed my mind" path.
+        set({ isLoading: false, error: null });
+        return;
+      }
+      const message =
+        err instanceof AuthenticationError
+          ? 'Authentication rejected by server'
+          : err instanceof Error
+            ? err.message
+            : 'OAuth login failed';
+      set({ isLoading: false, error: message });
+      throw err;
+    }
+  },
+
   logout: async () => {
     const accountStore = useAccountStore.getState();
     const currentId = get().activeAccountId;

src/test-setup.ts

@@ -64,3 +64,33 @@ vi.mock('expo-secure-store', () => ({
   getItemAsync: vi.fn(async () => null),
   deleteItemAsync: vi.fn(async () => undefined),
 }));
+
+// expo-auth-session and expo-web-browser transitively pull in
+// expo-modules-core, which evaluates RN-only globals at module load. The unit
+// tests don't exercise the real OAuth flow, so stubbing the surface is
+// enough — individual tests that need the real shapes can override.
+vi.mock('expo-auth-session', () => ({
+  AuthRequest: class {
+    codeVerifier?: string;
+    async promptAsync() {
+      return { type: 'cancel' as const };
+    }
+  },
+  ResponseType: { Code: 'code' },
+  exchangeCodeAsync: vi.fn(async () => ({
+    accessToken: 'test-access',
+    refreshToken: 'test-refresh',
+    expiresIn: 3600,
+  })),
+  refreshAsync: vi.fn(async () => ({
+    accessToken: 'test-access-refreshed',
+    refreshToken: 'test-refresh-rotated',
+    expiresIn: 3600,
+  })),
+  makeRedirectUri: () => 'bulwarkmobile://auth/callback',
+}));
+
+vi.mock('expo-web-browser', () => ({
+  warmUpAsync: vi.fn(async () => undefined),
+  maybeCompleteAuthSession: vi.fn(),
+}));