feat(zustand): add zustand stores for exam, timer and auth

stores/authStore.ts

@@ -0,0 +1,90 @@
+"use client";
+
+import { create } from "zustand";
+import { UserData } from "@/types/auth";
+import { API_URL } from "@/lib/auth";
+
+// Cookie utilities
+const getCookie = (name: string): string | null => {
+  if (typeof document === "undefined") return null;
+
+  const value = `; ${document.cookie}`;
+  const parts = value.split(`; ${name}=`);
+  if (parts.length === 2) {
+    return parts.pop()?.split(";").shift() || null;
+  }
+  return null;
+};
+
+const setCookie = (
+  name: string,
+  value: string | null,
+  days: number = 7
+): void => {
+  if (typeof document === "undefined") return;
+
+  if (value === null) {
+    document.cookie = `${name}=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/; SameSite=Strict; Secure`;
+  } else {
+    const expires = new Date();
+    expires.setTime(expires.getTime() + days * 24 * 60 * 60 * 1000);
+    document.cookie = `${name}=${value}; expires=${expires.toUTCString()}; path=/; SameSite=Strict; Secure`;
+  }
+};
+
+interface AuthState {
+  token: string | null;
+  isLoading: boolean;
+  user: UserData | null;
+
+  setToken: (token: string | null) => void;
+  fetchUser: () => Promise<void>;
+  logout: () => void;
+  initializeAuth: () => Promise<void>;
+}
+
+export const useAuthStore = create<AuthState>((set, get) => ({
+  token: null,
+  isLoading: true,
+  user: null,
+
+  setToken: (newToken) => {
+    set({ token: newToken });
+    setCookie("authToken", newToken);
+  },
+
+  fetchUser: async () => {
+    const token = get().token;
+    if (!token) return;
+
+    try {
+      const res = await fetch(`${API_URL}/me/profile/`, {
+        headers: {
+          Authorization: `Bearer ${token}`,
+        },
+      });
+
+      if (!res.ok) throw new Error("Failed to fetch user info");
+
+      const data: UserData = await res.json();
+      set({ user: data });
+    } catch (err) {
+      console.error("Error fetching user:", err);
+      get().logout();
+    }
+  },
+
+  logout: () => {
+    set({ token: null, user: null });
+    setCookie("authToken", null);
+  },
+
+  initializeAuth: async () => {
+    const storedToken = getCookie("authToken");
+    if (storedToken) {
+      set({ token: storedToken });
+      await get().fetchUser();
+    }
+    set({ isLoading: false });
+  },
+}));