feat: add auth

components/auth/auth-provider.tsx

@@ -0,0 +1,85 @@
+"use client";
+
+import {
+  createContext,
+  useCallback,
+  useContext,
+  useEffect,
+  useMemo,
+  useState,
+} from "react";
+import { auth, type User } from "@/lib/auth";
+
+/**
+ * AuthProvider holds the current-user state and exposes the auth actions
+ * to the rest of the app.
+ *
+ * On mount it calls /auth/me to hydrate. Until that completes, `loading`
+ * is true and consumers should render a placeholder rather than assuming
+ * the user is logged out.
+ *
+ * After a successful login/signup/logout the provider re-fetches /auth/me
+ * to keep state in sync with the cookie.
+ */
+type AuthContextValue = {
+  user: User | null;
+  loading: boolean;
+  signUp: (email: string, password: string, name: string) => Promise<User>;
+  logIn: (email: string, password: string) => Promise<User>;
+  logOut: () => Promise<void>;
+  refresh: () => Promise<void>;
+  /** Replace the user state without a network round-trip (after profile edit). */
+  setUser: (u: User | null) => void;
+};
+
+const AuthContext = createContext<AuthContextValue | null>(null);
+
+export function AuthProvider({ children }: { children: React.ReactNode }) {
+  const [user, setUser] = useState<User | null>(null);
+  const [loading, setLoading] = useState(true);
+
+  const refresh = useCallback(async () => {
+    try {
+      const me = await auth.me();
+      setUser(me);
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  useEffect(() => {
+    void refresh();
+  }, [refresh]);
+
+  const signUp = useCallback(async (email: string, password: string, name: string) => {
+    const u = await auth.signUp(email, password, name);
+    setUser(u);
+    return u;
+  }, []);
+
+  const logIn = useCallback(async (email: string, password: string) => {
+    const u = await auth.logIn(email, password);
+    setUser(u);
+    return u;
+  }, []);
+
+  const logOut = useCallback(async () => {
+    await auth.logOut();
+    setUser(null);
+  }, []);
+
+  const value = useMemo<AuthContextValue>(
+    () => ({ user, loading, signUp, logIn, logOut, refresh, setUser }),
+    [user, loading, signUp, logIn, logOut, refresh],
+  );
+
+  return <AuthContext.Provider value={value}>{children}</AuthContext.Provider>;
+}
+
+export function useAuth(): AuthContextValue {
+  const ctx = useContext(AuthContext);
+  if (!ctx) {
+    throw new Error("useAuth must be used inside <AuthProvider>");
+  }
+  return ctx;
+}