Fix: DataSync listener bug preventing updates from client to server

components/DataSync.tsx

@@ -4,34 +4,52 @@ import { useEffect, useRef } from 'react';
 import { useFinanzasStore } from '@/lib/store';
 
 export function DataSync() {
-  // const isHydrated = useFinanzasStore(state => state._hasHydrated); 
-  const store = useFinanzasStore();
   const initialized = useRef(false);
 
   useEffect(() => {
     async function init() {
+      // Prevent double init in StrictMode
       if (initialized.current) return;
-      initialized.current = true;
-
+      
       try {
         const res = await fetch('/api/sync');
+        // If 401 (unauthorized), stop here. User needs to login.
+        if (res.status === 401) return;
         if (!res.ok) return;
+
         const serverData = await res.json();
         
-        // Simple logic: if server has data (debts or cards or something), trust server.
-        const hasServerData = serverData.fixedDebts?.length > 0 || serverData.creditCards?.length > 0;
+        // Comprehensive check if server has ANY data
+        const hasServerData = 
+            (serverData.fixedDebts?.length ?? 0) > 0 || 
+            (serverData.variableDebts?.length ?? 0) > 0 ||
+            (serverData.creditCards?.length ?? 0) > 0 ||
+            (serverData.incomes?.length ?? 0) > 0 ||
+            (serverData.serviceBills?.length ?? 0) > 0;
         
         if (hasServerData) {
           console.log("Sync: Hydrating from Server");
           useFinanzasStore.setState(serverData);
         } else {
-            // Server is empty, but we might have local data.
-            // Push local data to server to initialize it.
-            console.log("Sync: Initializing Server with Local Data");
-            syncToServer(useFinanzasStore.getState());
+            // Server is empty. If we have local data, push it.
+            // But verify we actually have local data worth pushing to avoid overwriting with empty defaults unnecessarily
+            const localState = useFinanzasStore.getState();
+            const hasLocalData = 
+                localState.fixedDebts.length > 0 || 
+                localState.variableDebts.length > 0 ||
+                localState.creditCards.length > 0 ||
+                localState.incomes.length > 0;
+
+            if (hasLocalData) {
+                console.log("Sync: Server empty, pushing Local Data");
+                syncToServer(localState);
+            }
         }
       } catch (e) {
         console.error("Sync init error", e);
+      } finally {
+        // Mark as initialized so subsequent changes trigger sync
+        initialized.current = true;
       }
     }
 
@@ -40,10 +58,11 @@ export function DataSync() {
 
   // Sync on change
   useEffect(() => {
-    if (!initialized.current) return;
-
     const unsub = useFinanzasStore.subscribe((state) => {
-       syncToServer(state);
+       // Only sync to server if we have finished initialization/hydration
+       if (initialized.current) {
+          syncToServer(state);
+       }
     });
     return () => unsub();
   }, []);

data/db_renato97.json

@@ -0,0 +1,12 @@
+{
+  "fixedDebts": [],
+  "variableDebts": [],
+  "creditCards": [],
+  "cardPayments": [],
+  "monthlyBudgets": [],
+  "currentMonth": 1,
+  "currentYear": 2026,
+  "alerts": [],
+  "serviceBills": [],
+  "incomes": []
+}