Improve the frontend 2

frontend/src/contexts/SubscriptionEventsContext.tsx

@@ -0,0 +1,64 @@
+import React, { createContext, useContext, useState, useCallback, useEffect } from 'react';
+
+interface SubscriptionEventsContextType {
+  subscriptionVersion: number;
+  notifySubscriptionChanged: () => void;
+  subscribeToChanges: (callback: () => void) => () => void;
+}
+
+const SubscriptionEventsContext = createContext<SubscriptionEventsContextType | undefined>(undefined);
+
+export const SubscriptionEventsProvider: React.FC<{ children: React.ReactNode }> = ({ children }) => {
+  const [subscriptionVersion, setSubscriptionVersion] = useState(0);
+  const [subscribers, setSubscribers] = useState<Set<() => void>>(new Set());
+
+  const notifySubscriptionChanged = useCallback(() => {
+    setSubscriptionVersion(prev => prev + 1);
+    
+    // Notify all subscribers
+    subscribers.forEach(callback => {
+      try {
+        callback();
+      } catch (error) {
+        console.warn('Error notifying subscription change subscriber:', error);
+      }
+    });
+  }, [subscribers]);
+
+  const subscribeToChanges = useCallback((callback: () => void) => {
+    setSubscribers(prev => {
+      const newSubscribers = new Set(prev);
+      newSubscribers.add(callback);
+      return newSubscribers;
+    });
+
+    // Return unsubscribe function
+    return () => {
+      setSubscribers(prev => {
+        const newSubscribers = new Set(prev);
+        newSubscribers.delete(callback);
+        return newSubscribers;
+      });
+    };
+  }, []);
+
+  const value = {
+    subscriptionVersion,
+    notifySubscriptionChanged,
+    subscribeToChanges
+  };
+
+  return (
+    <SubscriptionEventsContext.Provider value={value}>
+      {children}
+    </SubscriptionEventsContext.Provider>
+  );
+};
+
+export const useSubscriptionEvents = () => {
+  const context = useContext(SubscriptionEventsContext);
+  if (context === undefined) {
+    throw new Error('useSubscriptionEvents must be used within a SubscriptionEventsProvider');
+  }
+  return context;
+};