feat(auth): implement user authentication and password change functionality

frontend/src/contexts/AuthContext.tsx

@@ -0,0 +1,159 @@
+import React, { createContext, useContext, useState, useEffect, ReactNode } from 'react';
+import { AuthState, IUser } from '../types';
+import * as authService from '../services/authService';
+
+// Initial auth state
+const initialState: AuthState = {
+  token: null,
+  isAuthenticated: false,
+  loading: true,
+  user: null,
+  error: null,
+};
+
+// Create auth context
+const AuthContext = createContext<{
+  auth: AuthState;
+  login: (username: string, password: string) => Promise<boolean>;
+  register: (username: string, password: string, isAdmin?: boolean) => Promise<boolean>;
+  logout: () => void;
+}>({
+  auth: initialState,
+  login: async () => false,
+  register: async () => false,
+  logout: () => {},
+});
+
+// Auth provider component
+export const AuthProvider: React.FC<{ children: ReactNode }> = ({ children }) => {
+  const [auth, setAuth] = useState<AuthState>(initialState);
+
+  // Load user if token exists
+  useEffect(() => {
+    const loadUser = async () => {
+      const token = authService.getToken();
+      
+      if (!token) {
+        setAuth({
+          ...initialState,
+          loading: false,
+        });
+        return;
+      }
+      
+      try {
+        const response = await authService.getCurrentUser();
+        
+        if (response.success && response.user) {
+          setAuth({
+            token,
+            isAuthenticated: true,
+            loading: false,
+            user: response.user,
+            error: null,
+          });
+        } else {
+          authService.removeToken();
+          setAuth({
+            ...initialState,
+            loading: false,
+          });
+        }
+      } catch (error) {
+        authService.removeToken();
+        setAuth({
+          ...initialState,
+          loading: false,
+        });
+      }
+    };
+    
+    loadUser();
+  }, []);
+
+  // Login function
+  const login = async (username: string, password: string): Promise<boolean> => {
+    try {
+      const response = await authService.login({ username, password });
+      
+      if (response.success && response.token && response.user) {
+        setAuth({
+          token: response.token,
+          isAuthenticated: true,
+          loading: false,
+          user: response.user,
+          error: null,
+        });
+        return true;
+      } else {
+        setAuth({
+          ...initialState,
+          loading: false,
+          error: response.message || 'Authentication failed',
+        });
+        return false;
+      }
+    } catch (error) {
+      setAuth({
+        ...initialState,
+        loading: false,
+        error: 'Authentication failed',
+      });
+      return false;
+    }
+  };
+
+  // Register function
+  const register = async (
+    username: string, 
+    password: string, 
+    isAdmin = false
+  ): Promise<boolean> => {
+    try {
+      const response = await authService.register({ username, password, isAdmin });
+      
+      if (response.success && response.token && response.user) {
+        setAuth({
+          token: response.token,
+          isAuthenticated: true,
+          loading: false,
+          user: response.user,
+          error: null,
+        });
+        return true;
+      } else {
+        setAuth({
+          ...initialState,
+          loading: false,
+          error: response.message || 'Registration failed',
+        });
+        return false;
+      }
+    } catch (error) {
+      setAuth({
+        ...initialState,
+        loading: false,
+        error: 'Registration failed',
+      });
+      return false;
+    }
+  };
+
+  // Logout function
+  const logout = (): void => {
+    authService.logout();
+    setAuth({
+      ...initialState,
+      loading: false,
+    });
+  };
+
+  return (
+    <AuthContext.Provider value={{ auth, login, register, logout }}>
+      {children}
+    </AuthContext.Provider>
+  );
+};
+
+// Custom hook to use auth context
+export const useAuth = () => useContext(AuthContext);