another step

client/src/context/auth/AuthContext.tsx

@@ -0,0 +1,24 @@
+'use client';
+import { createContext, useContext, useReducer } from 'react';
+import type { Dispatch, FunctionComponent, PropsWithChildren } from 'react';
+import { authReducer } from './authReducer';
+import { INITIAL_AUTH_STATE } from './types';
+import type { AuthAction, AuthState } from './types';
+
+export type AuthContextValue = [AuthState, Dispatch<AuthAction>];
+
+const AuthContext = createContext<AuthContextValue>([INITIAL_AUTH_STATE, () => null]);
+
+interface AuthProviderProps extends PropsWithChildren {
+  // Auth state resolved on the server from the request's access-token cookie.
+  // Seeding the reducer with it means the first client render already reflects
+  // the real session — no logged-out flash, no post-mount cookie read.
+  initialState?: AuthState;
+}
+
+export const AuthProvider: FunctionComponent<AuthProviderProps> = ({ initialState, children }) => {
+  const value = useReducer(authReducer, initialState ?? INITIAL_AUTH_STATE);
+  return <AuthContext.Provider value={value}>{children}</AuthContext.Provider>;
+};
+
+export const useAuth = (): AuthContextValue => useContext(AuthContext);

client/src/context/auth/authReducer.ts

@@ -0,0 +1,13 @@
+import type { Reducer } from 'react';
+import type { AuthAction, AuthState } from './types';
+
+export const authReducer: Reducer<AuthState, AuthAction> = (state, action) => {
+  switch (action.type) {
+    case 'LOG_IN':
+      return { isAuthenticated: true, currentUser: action.user ?? state.currentUser };
+    case 'LOG_OUT':
+      return { isAuthenticated: false };
+    default:
+      return state;
+  }
+};

client/src/context/auth/index.ts

@@ -0,0 +1,4 @@
+export { AuthProvider, useAuth } from './AuthContext';
+export type { AuthContextValue } from './AuthContext';
+export { INITIAL_AUTH_STATE } from './types';
+export type { AuthAction, AuthState } from './types';

client/src/context/auth/types.ts

@@ -0,0 +1,12 @@
+import type { User } from '@/services/auth/types';
+
+export interface AuthState {
+  isAuthenticated: boolean;
+  currentUser?: User;
+}
+
+export type AuthAction = { type: 'LOG_IN'; user?: User } | { type: 'LOG_OUT' };
+
+export const INITIAL_AUTH_STATE: AuthState = {
+  isAuthenticated: false,
+};