refactor: enhance invoice display logic and add empty state in BillingView

apps/mobile/packages/features/client/billing/lib/src/presentation/pages/billing_page.dart

@@ -10,7 +10,6 @@ import '../blocs/billing_state.dart';
 import '../widgets/invoice_history_section.dart';
 import '../widgets/payment_method_card.dart';
 import '../widgets/pending_invoices_section.dart';
-import '../widgets/savings_card.dart';
 import '../widgets/spending_breakdown_card.dart';
 
 /// The entry point page for the client billing feature.
@@ -199,7 +198,38 @@ class _BillingViewState extends State<BillingView> {
           ],
           const PaymentMethodCard(),
           const SpendingBreakdownCard(),
-          InvoiceHistorySection(invoices: state.invoiceHistory),
+          if (state.invoiceHistory.isEmpty) _buildEmptyState(context)
+          else InvoiceHistorySection(invoices: state.invoiceHistory),
+        ],
+      ),
+    );
+  }
+
+  Widget _buildEmptyState(BuildContext context) {
+    return Center(
+      child: Column(
+        mainAxisAlignment: MainAxisAlignment.center,
+        children: <Widget>[
+          const SizedBox(height: UiConstants.space12),
+          Container(
+            padding: const EdgeInsets.all(UiConstants.space6),
+            decoration: BoxDecoration(
+              color: UiColors.bgPopup,
+              shape: BoxShape.circle,
+              border: Border.all(color: UiColors.border),
+            ),
+            child: const Icon(
+              UiIcons.file,
+              size: 48,
+              color: UiColors.textSecondary,
+            ),
+          ),
+          const SizedBox(height: UiConstants.space4),
+          Text(
+            'No Invoices for the selected period',
+            style: UiTypography.body1m.textSecondary,
+            textAlign: TextAlign.center,
+          ),
         ],
       ),
     );

apps/mobile/packages/features/client/billing/lib/src/presentation/widgets/payment_method_card.dart

@@ -24,9 +24,11 @@ class _PaymentMethodCardState extends State<PaymentMethodCard> {
       return null;
     }
 
-    final fdc.QueryResult<dc.GetAccountsByOwnerIdData,
+    final fdc.QueryResult<
-            dc.GetAccountsByOwnerIdVariables> result =
+      dc.GetAccountsByOwnerIdData,
-        await dc.ExampleConnector.instance
+      dc.GetAccountsByOwnerIdVariables
+    >
+    result = await dc.ExampleConnector.instance
         .getAccountsByOwnerId(ownerId: businessId)
         .execute();
     return result.data;
@@ -36,19 +38,29 @@ class _PaymentMethodCardState extends State<PaymentMethodCard> {
   Widget build(BuildContext context) {
     return FutureBuilder<dc.GetAccountsByOwnerIdData?>(
       future: _accountsFuture,
-      builder: (BuildContext context,
+      builder:
-          AsyncSnapshot<dc.GetAccountsByOwnerIdData?> snapshot) {
+          (
+            BuildContext context,
+            AsyncSnapshot<dc.GetAccountsByOwnerIdData?> snapshot,
+          ) {
             final List<dc.GetAccountsByOwnerIdAccounts> accounts =
-            snapshot.data?.accounts ??
+                snapshot.data?.accounts ?? <dc.GetAccountsByOwnerIdAccounts>[];
-                <dc.GetAccountsByOwnerIdAccounts>[];
+            final dc.GetAccountsByOwnerIdAccounts? account = accounts.isNotEmpty
-        final dc.GetAccountsByOwnerIdAccounts? account =
+                ? accounts.first
-            accounts.isNotEmpty ? accounts.first : null;
+                : null;
-        final String bankLabel =
+
-            account?.bank.isNotEmpty == true ? account!.bank : '----';
+            if (account == null) {
-        final String last4 =
+              return const SizedBox.shrink();
-            account?.last4.isNotEmpty == true ? account!.last4 : '----';
+            }
-        final bool isPrimary = account?.isPrimary ?? false;
+
-        final String expiryLabel = _formatExpiry(account?.expiryTime);
+            final String bankLabel = account.bank.isNotEmpty == true
+                ? account.bank
+                : '----';
+            final String last4 = account.last4.isNotEmpty == true
+                ? account.last4
+                : '----';
+            final bool isPrimary = account.isPrimary ?? false;
+            final String expiryLabel = _formatExpiry(account.expiryTime);
 
             return Container(
               padding: const EdgeInsets.all(UiConstants.space4),
@@ -76,7 +88,6 @@ class _PaymentMethodCardState extends State<PaymentMethodCard> {
                       const SizedBox.shrink(),
                     ],
                   ),
-              if (account != null) ...<Widget>[
                   const SizedBox(height: UiConstants.space3),
                   Container(
                     padding: const EdgeInsets.all(UiConstants.space3),
@@ -141,7 +152,6 @@ class _PaymentMethodCardState extends State<PaymentMethodCard> {
                     ),
                   ),
                 ],
-            ],
               ),
             );
           },