refactor(mobile): AuthProvider exposes userKeyState instead of device record

apps/mobile/lib/authContext.tsx

@@ -1,23 +1,31 @@
 import type { Session, User } from '@supabase/supabase-js';
-import { auth, crypto } from '@chat-app/shared';
-import type { DeviceRecord } from '@chat-app/shared/auth';
-import { createContext, useCallback, useContext, useEffect, useState } from 'react';
-import { Platform } from 'react-native';
+import { fetchUserKeyBlob } from '@chat-app/shared/auth';
+import {
+  type ReactNode,
+  createContext,
+  useCallback,
+  useContext,
+  useEffect,
+  useState,
+} from 'react';
 
-import { secretStore } from './secretStore';
 import { supabase } from './supabase';
+import { cachedUserKey, ensureLegacyMigrated } from './userIdentity';
 
-// Locally-stored secrets keyed by stable names. Mirrors the desktop
-// convention so the migration tests (later) can compare snapshots.
-const KEY_DEVICE_ID = 'device.id';
-const KEY_DEVICE_PRIVKEY = 'device.privateKey';
+export type UserKeyState =
+  | { status: 'loading' }
+  | { status: 'needs-setup' }
+  | { status: 'needs-unlock'; lockedUntil: string | null; hasRecovery: boolean }
+  | { status: 'unlocked' };
 
 interface AuthContextValue {
   session: Session | null;
   user: User | null;
-  device: DeviceRecord | null;
+  userId: string | null;
   ownPrivateKey: Uint8Array | null;
-  loading: boolean;
+  userKeyState: UserKeyState;
+  ready: boolean;
+  refreshUserKeyState: () => Promise<void>;
   signOut: () => Promise<void>;
 }
 
@@ -29,44 +37,48 @@ export function useAuth(): AuthContextValue {
   return v;
 }
 
-export function AuthProvider({ children }: { children: React.ReactNode }) {
+export function AuthProvider({ children }: { children: ReactNode }) {
   const [session, setSession] = useState<Session | null>(null);
-  const [device, setDevice] = useState<DeviceRecord | null>(null);
   const [ownPrivateKey, setOwnPrivateKey] = useState<Uint8Array | null>(null);
-  const [loading, setLoading] = useState(true);
+  const [userKeyState, setUserKeyState] = useState<UserKeyState>({ status: 'loading' });
+  const [ready, setReady] = useState(false);
 
-  // Resolve or create the device record for this install given an active
-  // session. Stores the private key in expo-secure-store on first run.
-  const ensureDevice = useCallback(async (_currentSession: Session): Promise<void> => {
-    const savedDeviceId = await secretStore.getSecret(KEY_DEVICE_ID);
-    const savedPrivKey = await secretStore.getSecret(KEY_DEVICE_PRIVKEY);
-
-    if (savedDeviceId && savedPrivKey) {
-      const devices = await auth.listOwnDevices(supabase);
-      const deviceIdStr = new TextDecoder().decode(savedDeviceId);
-      const match = devices.find((d) => d.id === deviceIdStr);
-      if (match) {
-        setDevice(match);
-        setOwnPrivateKey(savedPrivKey);
-        return;
-      }
-      // Stored id no longer matches any device on the server (revoked,
-      // wiped). Fall through to register a fresh one.
+  const refreshUserKeyState = useCallback(async () => {
+    const s = session;
+    if (!s) {
+      setUserKeyState({ status: 'loading' });
+      setOwnPrivateKey(null);
+      return;
     }
-
-    const backend = crypto.getCryptoBackend();
-    const kp = backend.generateKeyPair();
-    const platform = Platform.OS === 'ios' ? 'ios' : Platform.OS === 'android' ? 'android' : 'linux';
-    const record = await auth.registerDevice(supabase, {
-      name: `Netralax Mobile (${Platform.OS})`,
-      platform,
-      publicKey: kp.publicKey,
+    setUserKeyState({ status: 'loading' });
+    const cached = await cachedUserKey(s.user.id);
+    if (cached) {
+      setOwnPrivateKey(cached);
+      setUserKeyState({ status: 'unlocked' });
+      void ensureLegacyMigrated(s.user.id).catch((err) => {
+        console.warn('legacy migration on auth-resume failed', err);
+      });
+      return;
+    }
+    const blob = await fetchUserKeyBlob(supabase, s.user.id);
+    if (!blob || !blob.exists) {
+      setUserKeyState({ status: 'needs-setup' });
+      return;
+    }
+    if (blob.locked) {
+      setUserKeyState({
+        status: 'needs-unlock',
+        lockedUntil: blob.lockedUntil,
+        hasRecovery: false,
+      });
+      return;
+    }
+    setUserKeyState({
+      status: 'needs-unlock',
+      lockedUntil: null,
+      hasRecovery: blob.recoverySealedPrivateKey !== null,
     });
-    await secretStore.setSecret(KEY_DEVICE_ID, new TextEncoder().encode(record.id));
-    await secretStore.setSecret(KEY_DEVICE_PRIVKEY, kp.privateKey);
-    setDevice(record);
-    setOwnPrivateKey(kp.privateKey);
-  }, []);
+  }, [session]);
 
   useEffect(() => {
     let cancelled = false;
@@ -74,48 +86,43 @@ export function AuthProvider({ children }: { children: React.ReactNode }) {
       const { data } = await supabase.auth.getSession();
       if (cancelled) return;
       setSession(data.session);
-      if (data.session) {
-        try {
-          await ensureDevice(data.session);
-        } catch (err) {
-          console.warn('[auth] ensureDevice failed', err);
-        }
-      }
-      setLoading(false);
+      setReady(true);
     })();
-
     const { data: sub } = supabase.auth.onAuthStateChange((_event, nextSession) => {
       setSession(nextSession);
+      setReady(true);
       if (!nextSession) {
-        setDevice(null);
         setOwnPrivateKey(null);
-      } else {
-        void ensureDevice(nextSession).catch((err) =>
-          console.warn('[auth] ensureDevice (state change) failed', err),
-        );
+        setUserKeyState({ status: 'loading' });
       }
     });
-
     return () => {
       cancelled = true;
       sub.subscription.unsubscribe();
     };
-  }, [ensureDevice]);
+  }, []);
 
-  const signOut = useCallback(async (): Promise<void> => {
+  useEffect(() => {
+    void refreshUserKeyState().catch((err) => {
+      console.warn('refreshUserKeyState failed', err);
+      setUserKeyState({ status: 'needs-setup' });
+    });
+  }, [session, refreshUserKeyState]);
+
+  const signOut = useCallback(async () => {
     await supabase.auth.signOut();
-    await secretStore.removeSecret(KEY_DEVICE_ID);
-    await secretStore.removeSecret(KEY_DEVICE_PRIVKEY);
-    setDevice(null);
     setOwnPrivateKey(null);
+    setUserKeyState({ status: 'loading' });
   }, []);
 
   const value: AuthContextValue = {
     session,
     user: session?.user ?? null,
-    device,
+    userId: session?.user.id ?? null,
     ownPrivateKey,
-    loading,
+    userKeyState,
+    ready,
+    refreshUserKeyState,
     signOut,
   };
   return <Ctx.Provider value={value}>{children}</Ctx.Provider>;