add backend auth

mobile/contexts/AuthContext.tsx

@@ -0,0 +1,90 @@
+import React, { createContext, useContext, useEffect, useState } from 'react';
+import { apiClient } from '../api/client';
+import { tokenStorage } from '../api/secureStorage';
+import { ENDPOINTS } from '../constants/api';
+import { AuthResponse, User } from '../types';
+
+interface AuthContextType {
+  user: User | null;
+  isLoading: boolean;
+  login: (username: string, password: string) => Promise<void>;
+  register: (username: string, password: string) => Promise<void>;
+  logout: () => Promise<void>;
+}
+
+const AuthContext = createContext<AuthContextType | undefined>(undefined);
+
+export function AuthProvider({ children }: { children: React.ReactNode }) {
+  const [user, setUser] = useState<User | null>(null);
+  const [isLoading, setIsLoading] = useState(true);
+
+  useEffect(() => {
+    loadUser();
+  }, []);
+
+  async function loadUser() {
+    try {
+      const stored = await tokenStorage.getUser();
+      if (stored) {
+        const userData = JSON.parse(stored) as User;
+        setUser(userData);
+      }
+    } catch {
+      await tokenStorage.deleteUser();
+    } finally {
+      setIsLoading(false);
+    }
+  }
+
+  async function login(username: string, password: string) {
+    const response = await apiClient.post<AuthResponse>(ENDPOINTS.AUTH_LOGIN, {
+      username,
+      password,
+    });
+
+    apiClient.setAccessToken(response.access_token);
+    await tokenStorage.setRefreshToken(response.refresh_token);
+    await tokenStorage.setUser(JSON.stringify(response.user));
+    setUser(response.user);
+  }
+
+  async function register(username: string, password: string) {
+    const response = await apiClient.post<AuthResponse>(ENDPOINTS.AUTH_REGISTER, {
+      username,
+      password,
+    });
+
+    apiClient.setAccessToken(response.access_token);
+    await tokenStorage.setRefreshToken(response.refresh_token);
+    await tokenStorage.setUser(JSON.stringify(response.user));
+    setUser(response.user);
+  }
+
+  async function logout() {
+    try {
+      const refreshToken = await tokenStorage.getRefreshToken();
+      if (refreshToken) {
+        await apiClient.post(ENDPOINTS.AUTH_LOGOUT, { refresh_token: refreshToken });
+      }
+    } catch {}
+
+    apiClient.setAccessToken(null);
+    await tokenStorage.deleteRefreshToken();
+    await tokenStorage.deleteUser();
+    setUser(null);
+  }
+
+  return (
+    <AuthContext.Provider value={{ user, isLoading, login, register, logout }}>
+      {children}
+    </AuthContext.Provider>
+  );
+}
+
+export function useAuth() {
+  const context = useContext(AuthContext);
+  if (!context) {
+    throw new Error('useAuth must be used within an AuthProvider');
+  }
+  return context;
+}